Protection from Radiation (Code of Practice) Regulations, 1990

Government Notice 292 of 1990

Protection from Radiation (Code of Practice) Regulations, 1990

Citation: Government Notice 292 of 1990
Primary work: Protection from Radiation Act
Date: 31 July 2002
Language: English
Type: Government Notice

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Tanzania

Protection from Radiation Act

Protection from Radiation (Code of Practice) Regulations, 1990

Government Notice 292 of 1990

Published in Tanzania Government Gazette
Commenced on 1 January 1991
[This is the version of this document at 31 July 2002.]
[Note: This legislation was revised and consolidated as at 31 July 2002 and 30 November 2019 by the Attorney General's Office, in compliance with the Laws Revision Act No. 7 of 1994, the Revised Laws and Annual Revision Act (Chapter 356 (R.L.)), and the Interpretation of Laws and General Clauses Act No. 30 of 1972. All subsequent amendments have been researched and applied by Laws.Africa for TANZLII.]

[Section 40(1); G.N. No. 292 of 1990]

Part I – Preliminary provisions (regs 1-19)

1. Citation

These Regulations may be cited as the Protection from Radiation (Code of Practice) Regulations.

2. Application

(1)These Regulations shall apply to—

(a)all users of radiation sources in medicine, veterinary practices, industry, teaching, research, agriculture, hydrology, geology, and other fields of human activity whenever such uses are subject to licensing under the Act;

(b)manufacturers, storekeepers, transporters and disposers of radiation sources and radioactive materials whenever such activities are subjected to registration or licensing under this Act;

(c)all persons who may be exposed to ionising radiation arising from the use of radiation sources and radioactive materials.

(2)Nothing in these Regulations shall apply to any material or use of any material which contains radioactivity of less than 3.7kBq (0.1 microcurie) or if there is no portion on it which the concentration exceeds 74 Bq per gramme (0.002 microcurie per gramme) or material, and other exemptions provided for in section 21 of the Act.

3. Prohibitions relating to use of a building

No person shall put to use a building for the purpose of installation, use of radiation devices or storage of radioactive materials without a compliance certificate or an acceptance certificate in the form set out in the First Schedule.

4. Duty to ensure safety

When the Commission gives a licence, the Management of an establishment shall as part of its responsibility for ensuring protection against ionising radiation, establish an adequate system of radiation monitoring and provide for the services necessary to perform the monitoring operations.

5. Organisation of a radiation monitoring system

When the radiation monitoring system is put in operation details of the duties it entails shall be distributed throughout the organisation, from the Management down to the individual, to the extent appropriate at each level, as indicated under this regulation.

(1)The Management shall—

(a)

(i)designate a technically competent person as a Radiation Safety Officer to advise on the development of an appropriate radiation monitoring programme with the establishment, to supervise its performance and to report to the Management the doses received by individuals;

(ii)the Radiation Safety Officer shall also help to advise or seek advice on improvements to protection measures and on the action to be taken if exposure limits have been or are likely to be exceeded;

(b)ensure that there is local supervision of the personnel monitoring system;

(c)develop procedures for the prevention or reduction of exposures;

(d)identify any new factors or charges in processes or procedures that may affect the degree of radiological protection control necessary; and

(e)develop monitoring plans for normal and abnormal radiation situations.

(2)Each worker, after receiving appropriate instructions, shall be responsible for the correct wearing of a dosimeter and for adhering to the procedures established for internal dose determinations.

6. Radiation individuals

(1)Occupational exposure comprises of status of all dose equivalents and committed dose equivalents incurred at work.

(2)The type and extent of individual monitoring required shall depend on the radiation associated with the work.

(3)In order to avoid problems of radiation protection of workers, the Commission in collaboration with the Radiation Protection Officer has set the following system of classification of working conditions—

(a)working condition A which describes conditions where the annual dose equivalents might exceed three-tenths of the relevant annual limits;

(b)working condition B which describes conditions where it is most unlikely that the annual dose equivalents will exceed three-tenths of the relevant annual limits; and if these conditions relate to the eventual possibility or reaching this dose equivalent and not to the dose equivalent actually incurred in a particular year, the classification of working conditions shall be reviewed periodically and whenever changes of programmes are made.

7. Provisions relating to individual monitoring

(1)For any person whose work has been classified as falling under working condition A, individual monitoring is necessary to demonstrate compliance with dose equivalent limits and shall therefore be provided.

(2)For a person whose work falls under condition B, monitoring of the working place is normally sufficient.

(3)Individual monitoring in working condition B may sometimes be performed to confirm that conditions are satisfactory or for the compilation of statistical data on dose distributions.

8. Prohibitions relating to working condition A

(1)No person below the age of 18 and no pregnant woman shall work under radiation condition A.

(2)Workers under this category shall be subject to individual monitoring for external radiation, internal contamination or both.

(3)The radiation status of these workers shall be checked periodically from adequate records of all occupational exposures.

(4)Where a new employee has worked with unsealed radioactive materials in the past (for example in nuclear power plant maintenance) monitoring for internal contamination shall be considered before he commences his new assignment.

(5)Employees who have worked with unsealed sources shall undergo a final monitoring for internal contamination before they terminate employment at an establishment.

(6)When the annual dose equivalent of an individual is likely to approach the limit, additional measures shall be required to show that exposures are within permitted dose limits; and these measures shall include supplemental dosimeter and whole body counting, also it shall be effective to use direct reading devices with adjustable alarm levels, particularly in radiation fields of high dose rates.

9. Individuals in working condition B

(1)Workers in this category shall not normally be subjected to individual monitoring for external radiation and internal contamination.

(2)Monitoring under subsection (1) shall be appropriate for new or revised operations during an initial experimental period to establish that such operations are of a high standard and to confirm that working condition B applies.

(3)Individual monitoring shall also be performed from time to time to confirm that conditions remain satisfactory, or for the compilation of statistical data on dose distributions.

10. Medical surveillance

Every worker under radiation risk shall be made to undergo proper medical examinations as prescribed by the National Radiation Commission Inspector.

11. Provisions relating to radiation accidents

(1)The evaluation of radiation protection shall also include a review of foreseeable types of radiation accidents.

(2)This review shall be done by a Radiation Protection Officer and shall consider the nature and magnitude of foreseeable accidents, the probability of reoccurrence, the consequences and the appropriate preventive measures.

12. Radiation in working areas

Working areas where radiation sources are to be used, stored or disposed of shall be classified according to potential level of exposure as follows—

(a)Restricted radiation areaswhere in normal procedures with radiation sources leads to the contamination of surfaces or the air may be extremely hazardous, or where the average dose equivalent rate is known to exceed 0.25 mSv/h. Access to the restricted areas shall be under the strict control of the Radiation Protection Officer who shall define the entry conditions. The restricted area shall be clearly indicated by appropriate area and warning signs;

(b)Controlled radiation areaswhere in normal procedures with radiation sources the expected contamination and radiation levels do not exceed 0.25 mSv/h, access to the controlled radiation areas shall be limited to persons who are directly engaged with radiation work. Entry by other persons shall be subject to the consent of the person in-charge of that area. Controlled areas shall be clearly indicated by appropriate area and working signs;

(c)Uncontrolled areasthese are areas within the confines of a radiation facility where the external radiation levels are negligible and where radioactive contamination is also not present. In order to avoid uncertainties in the determination of the extent of restricted and controlled areas, the boundaries shall when possible be walls and doors. Inside controlled areas indication shall be made by appropriate signs of the sites where work with radiation sources is carried out.

13. Training of radiation workers

Workers shall be suitably informed of the radiation hazard entailed by their work and the precautions to be taken. This shall require training in safety procedures and effective methods of avoiding unnecessary exposure.

14. Protective equipment

Necessary protective equipment shall be provided and its appropriate use shall be enforced.

15. Provisions relating to working conditions and equipment

Working conditions and equipments shall be reviewed from time to time to ensure that they remain as intended.

16. Installations

Final plans for new installations or for modifications of the existing installations involving structural shielding or other features relevant to protection against external irradiation, shall be approved by the Chief Radiation Protection Officer before building commences. Copies of the plans including specifications relevant to Radiation Protection shall be retained and readily available at the site.

17. Operating conditions

Before any equipment and, or installation where radiation sources are to be used, stored or disposed of, surveys shall be carried out in order to establish that the approved plans have been followed and that the shielding and operating conditions are such that they provide adequate protection against external and internal irradiation for all persons in accordance with the provisions under the Act; and subsequent surveys shall be made after every change in the radiation sources, equipment installations or conditions for use, storage or disposal that may affect the protection and at such intervals as may be necessary to check that satisfactory working conditions are maintained.

18. Reduction of over-exposure

Protection may be achieved by distance, shielding, reduction of exposure time, choice of radiation sources, that is radionuclides, techniques, exposure of manipulating radiation source, establishment and obeyance of appropriate laboratory rules, site of the installations or operations, use of individual protective devices and control of the access to working areas.

19. Protection of person in adjacent occupancy

In calculating the shielding parameters or requirements, steps shall be taken ensure that other persons in the vicinity or adjoining areas are appropriately protected from radiation exposure.

Part II – Protection against ionising radiation from external sources (regs 20-29)

20. Protection against ionising radiation from external sources

(1)In the planning of a radiation installation, account shall be taken of the maximum practicable work load of the equipment.

(2)The shielding of the radiation source and site of the installation in which it is situated shall be such that work may be carried out in compliance with the recommended dose limits for workers and members of the public.

21. X-ray equipment and sealed sources

(1)The exposure outside any auxiliary equipment such as high tension generators shall not exceed 0.2mSv per hour at 5 centimetres from the surface nor 0.02mSv per hour at any readily accessible place within the controlled area. Where the transformer or valve enclosure is located outside the controlled area it shall be necessary to reduce these exposures.

(2)A reliable indication shall be provided at the control panel and when practicable, also readily visible near the radiation beam aperture in order to show whether or not radiation is being generated.

(3)Warning indications shall be so designed so as not to give rise to a false feeling of safety, for example, lights indicating when the tube is not energized may be provided in addition to lights indicating that radiation is being generated; alternatively, lights of the latter type shall be so designed that the equipment cannot be operated if there is a failure of the indicator.

(4)Where the primary beam strikes material, secondary radiation will be generated and attention shall be given to the choice of absorber material and the arrangement of absorbers to minimise the secondary radiation which will include X-rays when electrons or beta particles are absorbed.

(5)High energy accelerators may produce noxious gases and materials (including air and dust) irradiated by the accelerator particles or by the photon beam and may become activated. Expert advice on these problems may be obtained from the Chief Radiation Protection Officer and any necessary safety measures for example choice of material and the installation of forced ventilation, shall be incorporated in the design material that may become activated. Shielding material, machine components, conveyer systems, beam defining systems and sample holders shall be monitored and any appropriate precautions instituted.

22. Beam equipment with sealed radioactive sources

(1)In the design of source housing, consideration shall be given to means whereby the integrity of the source housing is preserved in the event of fire; and information on the location of major radioactive sources shall be readily available to the appropriate fire authorities.

(2)A reliable indication shall be provided at the control panel and, when practicable, also at the source housing, in order to show when the source is in the ON position. There shall also be an indication capable of showing when the source is in the OFF position. Appropriate signs shall be displayed outside the irradiation room.

(3)The surface of the housing of the source capsule, particularly the beam aperture, together with any other locations likely to be contaminated in the event of a leakage, shall be tested for leakage or radioactive material at least once a year.

23. Sealed sources used without beam collimation

(1)A sealed source is considered to be any radioactive substance sealed in an inactive container or capsule, or bonded wholly within an inactive material, so as to prevent dispersion of the radioactive substance during routine use. It shall be noted that many sealed sources are fragile and may easily be damaged with consequent release of radioactive material. A sealed source may normally be regarded as exempted from these recommendations if it consists not more that 3.7 x 10⁴ Bq of Group 1 radionuclides or 3.7 x 10⁶ Bq of other radionuclides and will not give rise to a dose equivalent rate of not more that 10mSv per hour near its surface.

(2)Sealed sources containing activities exceeding those specified in subregulation (1) of this regulation, will need to be recognisable. Hence, whenever practical, all such sources shall be readily recognisable as being radioactive and the source container, capsule or bonding shall be labelled in such a way that the source can be identified; and if practicable, the nature and activity or the radioactive material shall be marked directly on the label, which shall be fire resistant.

(3)Actual or suspected loss of, or damage to, a sealed source shall be reported immediately to the person responsible for radiation safety within the facility.

(4)Local rules for the users' area shall be prepared detailing the manner of use of sealed sources and the procedure to be adopted in the event of loss of, damage to, or accidents involving a sealed source. In preparing such rules, consideration shall be given as appropriate, to factors such as possible cause of loss, spread of contamination, effect of fire, identification and treatment of causalities. A copy of local rules shall be sent to the Chief Radiation Protection Officer.

(5)When not in use, sealed sources, shall be stored under conditions which provide adequate protection for those entering and in adjacent areas to the store, security against unauthorised removal and minimum risk due to fire and flood. Where sources are liable to release radioactive gases or vapours, the store shall, if necessary, be mechanically ventilated to the outside air. Such ventilation may need to be continuous for an appropriate period before and whilst the store is open depending upon the activity and of radiotoxicity of the radionuclide concerned.

(6)Sealed sources shall be tested for leakage at appropriate intervals and at least once every year.

(7)Wherever there are reasonable grounds for believing that a sealed source is, or is liable to be leaking, it shall be hermetically sealed in a suitable container pending repair by the manufacturer or by a competent establishment. In such circumstances the area in which the source has been used and any person having used it shall be checked for contamination.

(8)In order to ensure the minimum irradiation of personnel engaged in preparation or application of sources, appropriate handling tools or implant instruments shall be used at all times. These tools shall be constructed so as to provide the maximum handling distance compatible with effective manipulation. All operators shall have adequate training, for example, with dummy sources, in these manipulative procedures; and whenever practicable remote means of manipulation which ensure adequate protection of staff, shall be used.

(9)An encapsulated source intended for the utilisation of beta radiation requires a thin window. This window and its mounting shall be so constructed as to minimise the risk of leakage of radioactive material and when not in use shall be covered by a shield of sufficient thickness to absorb all the beta radiation. When the window is being cleaned, or the source tested for leakage, care shall be taken to avoid damaging the window.

(10)It is understood that all beta sources emit bremsstrahlung and may cause other types of penetrating radiation such as X-rays, annihilation radiation and characteristic X-rays. Possible exposure from such radiation shall be evaluated and the necessary precautions taken.

(11)In the case of work that is undertaken outside fixed installations (for example mobile site radiograph) temporary barriers and warning signs to restrict access to the controlled area shall be used when necessary. Further information with regard to shielding of radiation sources will be given by the Chief Radiation Protection Officer.

24. Unsealed sources

(1)The provisions of regulation 23 of this Code of Practice relating to sealed sources shall be applied also to unsealed sources wherever appropriate.

(2)In dealing with unsealed sources special attention shall be paid to internal radiation hazards, for example, contamination, skin penetrations, ingestion or inhalation which shall be considered in addition to the usual radiation hazard of sealed sources. The extent of the protective measures to be taken will depend upon total activity, the specific activity, the radiotoxicity, the chemical and physical properties of the radionuclides or radioactive compounds.

25. Choice of radioactive material

When a choice between several radionuclides of varying toxicities is possible, the one with relatively low toxicity shall be used, and for this the Chief Radiation Protection Officer shall be consulted.

26. Choice of working methods procedure

(1)Good working procedures are so important that techniques shall be well thought out and understood before work is undertaken; and and these procedures shall be tried out in practice runs with inactive material so that when radioactive material is used, operations are performed speedily and confidently with minimum exposure and risk of accident; the working procedures shall be reviewed by the Radiation Protection Officer.

(2)The working methods shall be studies and procedures adopted to avoid as far as possible the dispersal of radioactive material, in particular through the formation of aerosols, gases, vapours or dust; and in addition, wet operations shall be planned to limit the spread or dispersal of radioactive materials and all unnecessary movement of persons or materials shall be avoided.

27. Design of working places

(1)The design of work places where unsealed radioactive materials are to be used, shall be aimed at minimising the release of radioactive material and waste into the working environment and at controlling and minimising the spread of radioactive material and waste into the environment; and to achieve these objectives all working places and laboratories belonging to restricted and controlled areas shall be classified in accordance with the following table—

Table 1. Limitation of activities in various types of working places or laboratories.
Radiotoxicity of radionuclides	Minimum significant quantity (x10 Bq)	Type of working place Laboratory required
		Type C(x10⁵)	Type B(x10⁷)	Type A(x10⁸)
Very high	0.37	3.7 or less	0.037 - 37.0	3.7 or above
High	3.7	37.0 or less	0.37 - 370.0	3.7 or above
Moderate	37.0	370.0 or less	3.7 - 3700.0	370.00 or above
Low	370.0	3700.0 or less	37.0 - 37000.0	3700.0 or above

Modifying factors may be applied to the quantities indicated in the last three columns of the table according to the complexity of the procedures to be followed. The following factors are suggested, but due regard shall be paid to the circumstances affecting individual cases—

Procedure-Modifying factor
Storage (stock solutions)	x	100
Very simple wet operations		10
Normal chemical operations	x	1
Complex wet operations with (risk of spill)	x	0.1
Simple dry operations	x	0.1
Dry and dusty operations	x	0.01

(2)The type "C" laboratory is a slightly modified modern conventional chemical laboratory having floors covered with linoleum or similar non-porous material, work benches with non-absorbent top surfaces, at least one good fume hood with induced draught, working surfaces including fume hood strong enough to carry any necessary shielding, the exhaust-air carried outside the building but need not be filtered.The type "B" laboratory is a specialised radioisotope laboratory designed so as to minimise the incidence and spread of the contamination, as well as to enable rapid and easy decontamination.The type "A" laboratory is a highly specialised laboratory for handling large quantities of radioactive materials and shall be designed and constructed by a competent organisation or enterprise and approved by the Chief Radiation Protection Officer.

(3)Appropriate changing room facilities shall be provided, where necessary, at the entrance to the controlled radiation area for the workers to change into the required protective clothing. Such facilities shall provide separate lockers for personal protective clothing and adequate facilities for washing of hands, and appropriate personnel monitoring equipment. Emergency shower facilities shall also be provided where appropriate. The changing room shall have an appropriate demarcation barrier between radioactive and non-radioactive areas.

(4)When the contamination level cannot be maintained below the required level, individual protection shall be provided in the form of air-line hoods or positive pressure masks. In cases where the use of air-line protective equipment is not practicable, special filter type respirators shall be used. Such respirators shall be of the type approved by a recognised laboratory test for the class of service required, and the practical safe limits of use shall be known and observed. The respirators shall be capable of standing up to the conditions of use and shall be checked and tested periodically. They shall be individually fitted and tested for adequacy of fit. Users of respirators shall accustom themselves to the discipline necessary in their use, otherwise harm may be done by introducing contamination under the face piece.

28. Use of proper individual protective devices

(1)Protective clothing appropriate to the radioactive contamination and associated risks shall be worn by every person in a controlled area even if only small quantities of radioactive materials are to be used. The type of protective clothing required depends upon the amount of radioactivity. The handling of even trace amounts will require laboratory coats over normal attire. When large quantities of radioactivity are handled, overalls or other clothing that completely cover the body shall be worn. The use of such clothing shall be restricted to the operational areas only. In such operation the risk of contamination may also require the use of special shoe coverings or the provision of shoes for use only in controlled or restricted areas.

(2)In type "C" working places, workers shall wear simple protective clothing such as ordinary laboratory or surgical coats. In type "A" or "B" working places protective clothing and devices shall be provided according to the nature of the work. The protective clothing for use in controlled radiation areas shall be clearly identified, for example by different colours and shall not in any case be worn outside the controlled areas. In addition, protective clothes and personal clothes shall be kept in separate cubicles or change rooms. When changing protective clothing care shall be taken to avoid contamination risks.

(3)Rubber, polyvinyl chloride and gloves shall be worn when working with unsealed radioactive substances to protect against contamination of the skin.

29. Laboratory rules

The Radiation Protection Officer shall be responsible for providing a set of general laboratory rules which shall be observed when handling unsealed radioactive sources. The rules shall include the following—

(a)eating, drinking, smoking and the use of cosmetics are strictly prohibited in controlled and restricted radiation areas;

(b)each person, when in a controlled or restricted radiation area, shall make proper use of the individual protective devices that are provided for his protection;

(c)pipetting or the performance of similar operations by mouth suction is strictly prohibited, and glass blowing shall be done by special techniques which avoid blowing by mouth;

(d)all work with radioactive materials shall be performed over easily decontaminable trays, the bottom of which shall be covered with absorbent paper;

(e)all operations involving volatile materials heating or digestion shall be carried out under a properly designed fume hood with an air velocity at the hood face of not less than 0.5m per sec.

(f)any operation in which particulate activity or radioactive dust may arise shall be carried out in a closed and adequately sealed glove box; and

(g)any accident involving radioactive materials shall be immediately reported to the Radiation Protection Officer.

Part III – Symbols to indicate ionising radiation (regs 30-31)

30. Requirements for appropriate use of warning signs and signs of devices in radiation areas

The requirements for appropriate use of warning signs and signs of devices in radiation areas are given in the following Table 2—

Table 2. Requirements for appropriate use of warning signs and signs of devices in a radiation area.
Area of concern	Radiation caution symbol	Cautioning words	Additional Regulation
Radiation areas	Yes	(danger) Radiation area	None
High Radiation area	Yes	(danger) Radiation area	Direct reading devices with adjustable alarm levels to warn presence of radiation fields of high dose rates
Airborne radioactivity area	Yes	(danger) Airborne radioactivity area	Same as above if area is also of high radiation
Entrance to areas/rooms in which radioactive materials are used or stored in an amount exceeding ten times the amount of derived concentration limits.	Yes	(danger) Radioactive material(s) and where practical, describe the quantities and kind of radioactive materials involved.	None
Radiation devices	Yes	(danger) Radiation	Label placed on the control panel
In case of X-ray machine only	Yes	(danger) X-ray area

III.Symbols to indicate ionising radiations1The basic symbol is of the design shown in figure 1.The symbol should be supplemented with a text with information of the nature of the risk (e.g."radioactive materials").2The symbol shall be in black colour and shall be placed on yellow or white background.3This symbol shall be used on labels, warning signs, tags, etc. When such symbols are used to indicate the presence of radiation sources, appropriate inscriptions may be used with it.FIG. 2. Category I - WHITE label. The background colour of the label shall be white, the colour of the trefoil and the printing shall be black, and the colour of the category bar shall be red.FIG. 3. Category II - YELLOW Label. The background colour of the upper half of the label shall be yellow and of the lower half white, the colour of the trefoil and the printing shall be black, and the colour of the category bars shall be red.FIG. 4. Category III - YELLOW Label. The background colour of the upper half of the label shall be yellow and the lower half white, the colour of the trefoil and the printing shall be black, and the colour of the category bars shall be red.

31. Labels to be used when transporting radioactive materials

Labels to be used when transporting radiative materials in accordance with these rules are given in figures 2, 3, and 4 for packages containing radiation sources dependent upon the category of the radioactive materials and, in figure 1, for vehicles transporting radiation sources.

Part IV – Storage of radiation sources (regs 32-34)

32. Place of storage

(1)When not in use radiation sources shall be kept in a place of storage assigned for this purpose only, bearing the appropriate warning symbol.

(2)The place of storage shall be adequately shielded such that at the outside surface of its walls or containment the radiation dose shall not exceed 01 mSv per hour, and shall be chosen so as to minimise risks from fire or flood.

(3)The place of storage shall be adequately secured with a lock to guard against unauthorised access. The key or keys for the store shall be held and controlled by an appropriate responsible person nominated for this purpose.

(4)The place of storage shall be inspected regularly and checked for possible contamination.

(5)The place of storage shall be sited and designed so as to ensure that both during storage and in the course of transfer of radiation sources to and from the store, the sources do not give excessive exposure to any person.

(6)If the place of storage is to contain either sealed or unsealed radiation sources that are liable to release a radioactive gas or vapour the store shall be continuously vented to the open air, or provided with a mechanical venting system that can be operated from outside the store before the store is opened.

33. Conditions of storage

(1)All radiation sources shall be clearly labelled, giving information on their activity and nature.

(2)The containers for beta emitting radionuclides shall have adequate thickness to reduce the primary radiation to a safe level. Considerable bremsstrahlung may arise from high intensity sources and additional shielding shall be provided if necessary.

(3)Gamma emitting and neutron sources shall be stored in such a way as to limit the radiation exposure from the other sources when any one source is being handled.

(4)Appropriate equipment shall be provided for storing unsealed radiation sources to prevent only external irradiation hazards but also internal contamination hazards.

(5)In type "C" working places the sources shall be stored in special cupboards providing adequate protection and security against unauthorised access.

(6)In type "B" working places a special secure receptacle shall be used which provides adequate protection that can be ventilated if necessary, and also provides security against unauthorised access.

34. Storage operations

(1)Records shall be kept of all stored radiation sources. These records shall give clear information on the type of source activity, times of removal and return, and the name of the person responsible for the source during its absence from the store.

(2)Inventories shall be taken periodically.

(3)Thermally unstable solutions containing radioactive material in citric acid or other oxidizing solutions containing traces of organic material, alpha activity in excess of 9 x 10⁸ Bq or beta activity in excess of 1.9 x 10⁹ Bq shall be stored in vented vessels.

(4)Solutions having a high activity (in excess of 3.7 x 10⁷ Bq/m³) shall not be stored in thin walled glass bottles, since irradiation might weaken the glass. All glass vessels might be expected to fail without apparent cause.

(5)Bottles containing radioactive liquids shall be placed in non-fragile vessels large enough to hold the entire contents of the bottles in case of breakage.

Part V – Transport of radiation sources (regs 35-36)

35. Transport within licensed premises

(1)The competent person or Radiation Protection Officer identified at the establishment shall be responsible for the precautions to be taken in the movement of radioactive substance from one area to another within the establishment.

(2)Radioactive substances shall be transported within the licensed premises only in containers provided for the purpose and should properly be labelled. Such containers shall be designed—

(a)to provide adequate protection for all persons during loading, transport and unloading (type "A"); and

(b)to prevent loss of radioactive material and to minimise the risk of spilling unsealed radioactive sources (type "B");

(c)radioactive materials may be moved within the establishment in packing intended for transport outside the establishment.

36. Transport within and outside the country

(1)Transport may be by road, rail, and air or sea. Licence for the transportation outside shall be issued by the Commission.

(2)Packaging of radiation sources shall try be designed so as to provide the necessary shielding against ionising radiations and to adequately prevent loss and spillage of radioactive materials during transport operation in case of transport accidents.

(3)According to radiation levels, packages containing radiation sources are placed in one of the following three categories—

(a)Category I - WhiteThe radiation level originating from the package at any time during normal transport shall not exceed 5 mSv per hour at any location on the external surface of the package.

(b)Category II - YellowThe radiation level originating from the package at any time during transport shall not exceed 0.5 mSv per hour at any location on the surface of the package, and 0.10 mSv per hour measured at one metre from the external surface of the package.

(c)Category III - Yellow

The radiation level originating from the package at any time during transport shall not exceed 2 mSv per hour at any location on the external surface of the package and 0.1 mSv per hour measured at one metre from the external surface of the package.

(4)Depending on the quantity of radioactive materials contained in it, the package may be of type "A" or "B".

(5)The loose radioactive contamination on any external surface of the package shall be kept as low as practicable and shall not exceed the values given in table 3 below:

Table 3. Maximum Permissible Level (M.P.L¹1) of loose contamination on packages.
Contaminant	MPL²2 (Bq/Sq. cm)
U-nat, U-depleted and Th-nat	37.00
Beta and gamma emitters and low toxicity alpha emitters ³3	3.70
All other alpha emitters	0.37

¹Average over 300 sq. cm. of any part of the surface.²Average over 300 sq. cm. of any part of the surface.³Low toxicity alpha emitters: U-25; U-28; Th-22; Th-228 and Th-20, when diluted to a specified activity of the same order as that of U-nat radionuclides with a half life of less that 10 days. U-nat & Th-nat mean Natural Uranium and Natural Thorium respectively.

(6)When transporting radiation sources, care shall be taken that persons involved are not exposed to ionising radiation in excess of the limits given in the second Schedule.

(7)All packages containing radiation sources shall be separated from undeveloped photographic films or plates so that these are not exposed to more than 10 mSv.

(8)Packages of radioactive materials shall be stored in separate transit areas for as short a time as practicable and far from other hazardous materials.

Part VI – Radiation monitoring (regs 37-46)

37. Radiation monitoring defined

(1)Monitoring is the general term used for all measures related to the assessment of exposure to ionising radiation arising from external and internal radiation sources.

(2)Monitoring programmes shall be designed to meet clearly defined objectives and these shall be recorded. The design of monitoring programme must include the basis of interpretation in relation to the objectives. This basis shall be recorded. Finally, the design shall incorporate guidance on what records are necessary and on the associated record-keeping and record-destruction procedures.

38. Requirements monitoring programmes

The following monitoring programmes shall be designed—

(1)Monitoring of work places. It is convenient to subdivide the monitoring of work places into three distinct types:

(a)monitoring of working environment;

(b)operational monitoring;

(c)special monitoring.

(2)Personnel monitoring.

(3)Environment monitoring.

39. Monitoring of the working environment

(1)This is intended to show that the working environment is satisfactory for continued operations and that no change has taken place calling for a reassessment of operating procedures. It is largely of a confirmatory nature but may not include the use of fixed detectors to identify the on set of abnormal or emergency conditions. The inspections and licensing section of the National Radiation Commission shall carry out the measurement on request.

(2)The most important part of the programme of monitoring for external radiation in the work places is the conduct of a comprehensive survey when any new installation is put into service or when any substantial changes have been made, or may be made, in an existing installation.

(3)If the radiation situation in a work place is not liable to change, except as a result of substantial alteration to the protective equipment or the processes carried out in the work place (which shall be followed by comprehensive surveys), then routine monitoring of the working environment is not necessary. If, however, the radiation fields in the work place are liable to change, but the changes are not likely to be rapid or severe, then occasional checks, mainly at fixed points, shall be carried out and will usually give sufficient warning of deteriorating conditions. Alternatively, the results of personnel monitoring for external radiation may be used for this purpose. If the radiation fields are liable to increase rapidly to serious levels, then a system of warning instruments shall be installed at fixed points in the working area or be worn individually by the workers. It is particularly important to identify situations calling for this type of warning systems because if carried out effectively, it can prevent exposure to high doses of radiation and thus eliminate a dangerous situation.

(4)The control of contamination in operations with unsealed radioactive materials requires a succession of defensive barriers, that is, the principle of defence in depth. The material shall be confined so far as is practicable at the point of use by the adoption of appropriate working procedures but there may be some degree of spread away from this point and the working place itself is regarded as a subsidiary part of the overall containment.

(5)The principal objectives of a programme of monitoring for surface contamination can be summarised as follows—

(a)to detect failure of containment;

(b)to detect departures from good operating procedures;

(c)to limit surface contamination to levels at which the general standards of good house keeping are adequate to avoid exposures to radiation approaching the recommended standard and;

(d)to provide information for the planning of programmes for additional personnel monitoring and air monitoring, and for defining improved working procedures;

(e)monitoring of the working environment for air contamination will rarely be needed on a routine basis except in the following circumstances—

(i)where gaseous or volatile materials are handed in big quantities, for example, tritium and its compounds in large scale production processes, the oxide in heavy water reactors, and iodine isotopes at levels of a few hundred millicuries);

(ii)the handling of any radioactive material (including reactor fuel fabrication and reprocessing, and the machining of natural and enriched uranium) in conditions of frequent and substantial contamination of work places;

(iii)the processing of plutonium and other transuranium elements; and

(iv)uranium mining, milling and refining.

40. Operational monitoring

(1)Operational monitoring is intended to provide a check on a particular operation and give, if necessary, a basis for immediate decisions on the conduct of the operation. It is particularly appropriate in the control of short term procedures under conditions which will be unsatisfactory for continued long term use.

(2)The design of an operational monitoring programme depends greatly on whether the operations to be carried out influence the radiation fields or whether these will remain substantially constant throughout the operations. In the latter case a preliminary survey of the radiation dose rate in the region to be occupied by the workers shall be carried out and will usually be sufficient, though this may have to be repeated before each series of operations. If the operations themselves influence the dose rates then a continued series of measurements shall be made throughout the operation. The detailed design of such a survey must depend critically on the form of operation and on the conditions under which it takes place.

41. Special monitoring

Special monitoring shall be carried out in the working environment when insufficient information is available to achieve adequate control, or when an operation is being carried out either for the first time or in abnormal circumstances.Special monitoring is intended to provide more detailed information in order to determine the problems and to define future procedures. Any programme of special monitoring shall therefore have a limited duration and clear cut objectives and give way to appropriate monitoring of the working environment or operational monitoring once the objectives have been achieved.

42. Personnel monitoring

(1)Personnel monitoring is the making and interpreting of measurements made by equipment carried on an individual worker or measurements made of the activity in their bodies or excreta.The primary purpose of such monitoring is to obtain an estimate of the total dose or dose commitment to selected organs and tissues, and to discover accidental exposures. For routine monitoring, the period of interest extends over months or years.If the doses are well below the relevant dose limits, the upper limit rather than the actual value of the dose will be sufficient, for example by use of investigative levels. Where personnel monitoring is not practicable for some types of exposure for example intermediate energy neutrons from radon, thoron, thorium and their daughters, special programmes of monitoring the work places shall have to be instituted to provide estimates of doses or intakes concerned.

(2)The Personnel monitoring for external radiation is carried out by the Radiation Protection Services department of the National Radiation Commission, using Thermoluminescent Dosimeters. The dosimeters are used by radiation workers for one month on the upper left part of the chest and after this period are sent back for evaluation. The results of personnel dose measurements are sent to the appropriate Radiation Safety Officers. The licence for the use of radiation sources is conditional upon the introduction of personnel dosimetry for all workers who are under risk of irradiation.

(3)The results of personnel monitoring shall be used to give information about the conditions in the work place and, which methods of personnel monitoring are cheap and easy to interpret. This will often provide a simple way of establishing whether the general conditions in the work place are under satisfactory control.

(4)All radiation workers shall be under medical supervision. Where any person has received a radiation dose in excess of the recommended standards (Second Schedule) the Chief Radiation Protection Officer shall decide whether or not to carry out a medical examination of the person, or such other investigation as may be indicated, and arranged for appropriate medical treatment where necessary. The Chief Radiation Protection Officer shall also determine whether he may continue his work or shall be suspended from it, shall determine the period of any suspension.

43. Internal monitoring

Programmes of monitoring for internal contamination are usually costly in scientific and technical manpower, and it is therefore important that the selection of workers to be monitored shall be appropriate. Experience has shown that routine individual monitoring for internal contamination will rarely be needed. The National Radiation Commission inspector together with the Radiation Safety Officers shall decide whether or not such measurement is needed.

44. Area monitoring

The assessment of doses in minor accidents is usually adequately covered by means of regular dosimeters for individual monitoring. The likelihood and probable magnitude of these events can be noted on the dosimeters. In some circumstances, severe exposures are possible though very unlikely. Two typical situations are—

(a)operational errors or equipment failure may occur when large amounts of radioactivity are being transferred within or between shields;

(b)failure of interlocks may occur with high dose-rate equipment such as X-ray sets or accelerators. The Radiation Safety Officer shall be responsible for such measurements.

45. Environmental monitoring

Environmental monitoring means the measurement of radiation and radioactivity outside boundaries of installations handling radioactive materials or radiation sources, and shall include measurements made necessary by the operation of these installations. Monitoring of the process and of the release of waste are closely connected with any environmental monitoring programme and, for the great majority of installations, provide efficient information to make environmental monitoring unnecessary. The environmental monitoring programmes shall be carried out by the National Radiation Commission.

46. Emergency surveys

Emergency surveys may be needed around any installation handling sufficiently large amounts of radioactive materials to constitute a potential hazard to people outside the installation. Such surveys may also be required following accidents in the transportation of radioactive materials. The Chief Radiation Protection Officer will decide if such surveys will have to be done.

Part VII – Record keeping and relevant action (reg 47)

47. Radiation dose records

(1)The licensee shall arrange for the following records to be kept, where relevant—

(a)radiation dose records;

(b)cases of overexposure;

(c)transfer records;

(d)medical records;

(e)cases of contamination of skin, hair and clothing;

(f)area monitoring;

(g)calibration of monitoring instruments and dose rate meters;

(h)alteration of output or quality of radiation as a result of modification or maintenance of the source;

(i)tests of individual protection devices;

(j)leakage tests of sealed radioactive sources;

(k)administration of permanent implants;

(l)list of all sealed radiation sources in stock with dates of receipt;

(m)list of all sealed radiation sources issued from and returned to the store, with appropriate dates and signatures of users;

(n)stock of unsealed radioactive materials, with dates of receipt, issued and disposal;

(q)investigation of emergencies and accidents; and[Please note: numbering as in original.]

(r)disposal of radioactive wastes.

(2)The radiation dose records shall be established for every worker in accordance with Part V of this Code. The record shall show the doses, both from external and internal radiation sources, received as a result of previous work with ionising radiation, and doses received in any one year and last thirteen consecutive weeks. Emergency and accident doses shall also be noted on the record. These records shall be retained for a period of thirty years after the last record.

(3)The transfer record is the summary of the radiation dose record issued to worker terminating the employment. The worker shall produce this record when taking a new work involving exposure to ionising radiation. The transfer record shall be retained for thirty years after date of issue.

(4)The medical records shall contain results of all medical examinations (employment, routine and after emergency or accidental exposures) for the workers in the course of his employment. These records shall be retained for thirty years after the last entry.

(5)All contaminations of the skin, head and clothing which cannot be reduced by first aid measures to a level below the maximum permissible contamination levels given in the Radiation Protection Standard shall be recorded. This record shall be attached to the medical record and retained for two years. The records shall indicate the case of contamination, the action taken to deal with it and the length of time during which the excess contamination lasted.

(6)Area monitoring results shall be recorded for future reference.

(7)Calibration records shall contain the results or calibration, date when calibration was performed and data about any repair or maintenance work done on the instrument. These records shall be retained for two years after last entry.

(8)Any action that will permanently change the output or quality of radiation shall be recorded in detail.

(9)All individual protective devices whose characteristics or readiness for use may change with time shall be tested at intervals of six months and the results of tests recorded.

(10)All tests of sealed radiation sources for leakage shall be recorded, showing dates and results of the tests.

(11)All administration to patients of permanent implants shall be adequately recorded.

(12)Receipt of all sealed radiation sources shall be recorded, showing dates and also the date of disposal or transfer to another licensee.

(13)If there is a main store for sealed sources the issue and return of them to the store shall be recorded together with the place of use and the name of the users. If necessary a responsible person may be appointed in charge of the stock of sources.

(14)All administration to patients of unsealed radioactive materials shall be properly recorded.

(15)All treatment and diagnosis using ionising radiation shall be recorded and the records be readily available for transfer from one hospital to another.

(16)All unsealed radioactive materials in stock, their issuance; and eventual return to the store as well as the purpose of issuance and recipient, shall be recorded. If necessary a person may be nominated for dispensing the unsealed radioactive materials.

(17)Investigation of emergencies and accidents, and the corresponding conclusions shall be recorded in detail for future reference.

Part VIII – Decontamination (regs 48-52)

48. Human decontamination

Measures to be taken in case of internal contamination of personnel. Internal radioactive contamination of personnel can result from ingestion, inhalation, or penetration of the skin through a wound. If internal contamination is suspected as a result of an accident during work, it should be immediately reported to the person responsible for radiation protection. Internal contamination is essentially a medical problem, parallel in some ways to the absorption of chemical toxins. Any special corrective procedures needed should therefore the carried out in combination with normal medical attention and under medical advice and supervision, and shall be reported in writing to the Chief Radiation Protection Officer (CRPO).

49. Measures to be case of external taken in contamination of personnel

(1)External contamination of a person can be a hazard in three ways—

(a)it may cause injury from local exposure of skin;

(b)it may penetrate the intact skin (particularly in the presence of certain organic solvents);

(c)it may eventually be transferred into the body by ingestion or inhalation.

(2)The danger of loose activity being eventually carried into the body is often the most critical hazard, hence decontamination procedures are primarily concerned with loose contamination.

(3)As a rule except for decontamination of the hands or in cases of emergency as agreed upon by the person responsible for radiation protection, all mild decontamination procedures described in subregulations (4) and (5) of this regulation should be carried out under the supervision of the person responsible for radiation protection. Attempts to remove contamination which resists mild procedures should be made only under medical supervision.

(4)The immediate washing of contaminated areas with water and soap is the method of choice for removing loose contamination subject to the following elementary precautions—

(a)tepid water shall be used;

(b)the soap shall not be abrasive nor highly alkaline;

(c)washing can be helped by scrubbing with a soft brush, but only in such a way as not to ablaze the skin; and

(d)the skin shall be washed for a few minutes at a time, then dried and monitored. Washing can be repeated if necessary (as indicated by monitoring) provided that there is no indication of damage to the skin.

(5)If these procedures fail, mild detergent approved by persons responsible for radiation protection may be used, although repeated applications of detergent to the same area of the skin (for example hands) might injure it and make it penetrable. The use of organic solvents or acid or alkaline solutions shall be avoided.

(6)Special attention shall be paid to proper contamination of creases, folds, hair and such parts of the hands as finger nails, interfinger spaces and the outer of the hands.

(7)Care shall be taken to avoid as far as possible the spread of the contamination to uncontaminated parts of the body and to avoid internal contamination. If there is a risk of such spread, an attempt shall first be made to remove the contamination with absorbent material, if necessary, adequately covering at the same time the adjacent non-contaminated areas of the skin. In general an open wound shall be protected against any additional contamination by decontamination procedures applied to other areas.

(8)After each decontamination operation, the treated place shall be dried with fresh non-contaminated towels and swab, and monitored; and all towels and swabs so used shall be treated as contaminated materials.

(9)While decontaminating the face, special care shall be taken not to contaminate the eyes or lips.

(10)Decontamination of eyes shall be undertaken immediately. Not only is the radionuclide to be considered but also the chemical nature of the contaminant and possible complication due to the foreign bodies and mechanical or chemical irritants. Additional irradiation of the eyes by decontamination procedures shall be avoided. Immediate irrigation of the eyes with copies amount of water or with appropriate approved chemical solutions is recommended. These solutions and a suitable vessel for eye washing shall be provided as first-aid kit. After this first procedure every case of contamination of the eyes shall be submitted to medical control and further treatment.

(11)Attempt to remove contamination which resists washing shall only be made under medical supervision.

50. Decontamination of equipment

A decision to decontaminate equipment must take into account the continuing value of the equipment compared with the risks and cost of decontamination, and the cost of disposal or radioactive waste.

(1)Decontamination methods for equipment are of two kinds—

(a)removal of contamination without damage of the surface below;

(b)removal of the surface of the equipment together with the adhering contamination.

In all cases the first method shall be used initially and only if several attempts fail shall the second method be tried since damaged surfaces may be unsuitable for reuse because of the tendency to collect contamination easily.

(2)Where the half-life of the contaminating radionuclide is short, it may be desirable to store the equipment for decay of activity rather than to attempt decontamination.

(3)Decontamination of equipment shall generally be done as soon as possible after its use; and in many cases this will prevent the contaminant from becoming fixed and from being ultimately more difficult to deal with. It will often be found that surfaces that have been kept moist are easier to clean.

(4)The cleaning of contaminated glassware and other tools shall be done with great care by informed persons in a well ventilated hood set aside in the laboratory for that purpose, or special decontamination areas.

(5)If it is necessary to dismantle any equipment before decontamination procedures, careful monitoring shall be carried out during the operation.

51. Decontamination of working areas and benches

(1)As soon as possible after contamination of working areas, benches, tables, et cetera, has occurred or has been detected, decontamination shall be carried out by suitably equipped and informed personnel.

(2)All surfaces shall be cleaned by wet methods if possible as the use of dry methods may create a dust hazard.

52. Decontamination of clothing, hospital linen and similar items

(1)In any handling of contaminated clothing, appropriate precautions shall be taken to control external exposure and also to prevent or control contamination of the worker and of the surrounding areas by the formation of aerosols; and all contaminated clothing, hospital linen and similar items shall be placed in suitable plastic bags which shall then be sealed and labelled with the appropriate symbol and information as to its origin and type of contamination.

(2)Contaminated clothing or bedding must not be sent to public laundries unless the activities, averaged over an area not exceeding 100 sq. cm, are everywhere below the maximum permissible contamination levels.

(3)In the case of short-lived radioactive contamination, storage is normally recommended until the activity has reduced to safe levels.

(4)It will usually be desirable to wash contaminated clothing in specially designed laundry facilities and the area where decontamination is carried out be monitored. Personnel working in these facilities shall be provided with dosimetry badges.

(5)Rubber gloves and other rubber goods and plastics are usually decontaminated readily. Such items shall first be washed using ordinary laundry formula. If this does not prove effective, rubber items can be washed in dilute nitric acid or other detergents chosen according to the nature of the contamination. This shall be followed by washing using scouring powder in running tap water.

(6)If the clothing, linen, et cetera cannot be decontaminated to a safe level it shall be treated as radioactive waste.

Part IX – Radioactive waste (regs 53-57)

53. Waste collection

(1)Suitable receptacles for waste shall be available in all working places where radioactive waste may originate.

(2)Solid waste shall be deposited in refuse bins with foot-operated lids. The bins shall be lined with removable plastic or paper bags to facilitate removal of the waste without contamination.

(3)If no licensed facilities for liquid waste disposal exist liquid waste shall be collected in bottles, kept in pails or trays designed to retain all their contents in the event of a breakage. Special containers which are provided with a suitable absorbent material for safe storage or licensed disposal are made available for liquid waste.

(4)All receptacles for radioactive wastes shall be clearly identified. In general it will be desirable to classify radioactive waste according to methods of storage or disposal and to provide separate containers for the various classes of waste. Depending upon the need of the installation, one or more of the following categories for classifying waste may be found desirable—

(a)gamma radiation levels (high, low);

(b)total activity (high, medium, low);

(c)half-life (long, short);

(d)combustible, non-combustible.

For convenient and positive identification, it may be desirable to use both colour, coding and wording.

(5)Shielded containers for radioactive waste shall be used when necessary in order to keep the radiation dose outside the container below the recommended level.

(6)Under the licence granted for accumulation and disposal of radioactive waste it is required that records shall be maintained of all radioactive wastes released to drainage systems or sewers, or disposed of by incineration or to the centre determined by the National Radiation Commission. These records shall contain information on the radionuclides, estimated radioactivity, volume and date of disposal. For this purpose it will be necessary to maintain a record of estimated quantities of radioactivity and radioisotopes deposited in the various receptacles at the work places, and for the receptacles to be labelled appropriately with this information.

(7)Radioactive waste shall be removed from working places to a suitably designed storage area with adequate shielding and security by a designated personnel under competent supervision.

54. Release of radioactive wastes to the environment

Release of radioactive wastes to the environment shall be carried out in accordance with the conditions established in the licence for the accumulation and disposal of radioactive wastes issued by the Commission in Schedule I.

55. Release of liquid radioactive waste to drains and sewers

The release of radioactive effluent to drains and sewers shall be carried out only in accordance with the conditions established in the licence for the accumulation and disposal of radioactive waste issued by the Commission in Schedule II.

56. Incineration of radioactive wastes

The incineration of radioactive wastes shall be carried out in a suitably designed incinerator approved by the Chief Radiation Protection Officer and under the conditions established in the licence for the accumulation and disposal of radioactive wastes issued by the Commission in Schedule I.

57. Radioactive waste storage

(1)All radioactive waste which cannot be immediately disposed of in conformity with the licence issued by the Commission shall be placed in a suitable storage.

(2)Storage of radioactive waste may be necessary to allow decay of short lived radionuclides to an activity level below the standard laid down for disposal via the non-active waste disposal routes, or by the radioactive waste disposal routes granted in the licence for accumulation and disposal of radioactive waste. Any radioactive waste that cannot be disposed of locally under this licence due to the activity levels of long-lived isotopes shall be transferred as soon as practicable to the place of storage.

Part X – Radiation accidents and emergencies (reg 58)

58. Radiation accident

(1)A radiation accident is an unusual occurrence resulting from the loss of control over a radiation source which can indirectly involve hazards to life, health and property. A radiation accident may occur at any stage of an operation involving radiation sources.

(2)Radiation accidents will normally conform to one of the following broad general patterns—

(a)accidental external exposure to excessive amounts of radiation, for example when a person inadvertently remains close to a strong source or accidentally gets exposed to a beam of radiation;

(b)accidental spill or incident in a working place resulting in surface and air contamination of personnel; and in such cases the intake of radioactive materials into the body can be by inhalation, through open wounds resulting from the incident, or by direct absorption through the skin; and

(c)release of radioactive material into the environment as a result of an explosion, fire, mechanical shock or other incidents occurring on the licensed premises or in a public place when radioactive materials are being transported.

(3)The licensee has a responsibility to reduce as far as practicable any risks to his employees and other persons. He shall ensure that proper procedures are available so that if an accident shall occur, immediate steps are taken to protect the workers and other persons.

(4)In any incident, the first concern shall be protection of persons involved and the treatment of any serious injury. The second concern is to confine the contamination as far as possible to the area originally affected. Decontamination of personnel shall also take priority over any plan for decontamination of working areas, although immediate arrangements shall be made to restrict the spread of contamination.

(5)In every licensed premises for radiation sources local instructions shall be drawn up and made known to all workers and other persons within the establishment specifying—

(a)the person to be notified of an accident;

(b)immediate action to be taken; and

(c)the location of equipment for dealing with accidents.

(6)The designated Radiation Safety Officer shall provide instructions which shall be displayed at appropriate places in controlled radiation areas and other appropriate departments of the licensed premises for dealing with accidents or incidents involving radioactive materials.

(7)The following shall be kept in mind when drawing up instructions and plans for accident or incident situations—

(a)persons in the immediate vicinity shall be warned of the accident;

(b)all functioning laboratory apparatus shall be made safe and, normally, other laboratory services and ventilation except lighting, shall be switched off. All doors and windows shall be closed to restrict the spread of contamination by draughts. Access to the scene shall be restricted. However in those circumstances where radioactive gas or vapour, for example treated water vapour, is dispersed, the mechanical ventilation shall be left on and, according to discretion, the doors and windows shall be opened;

(c)access to and traffic through the affected areas shall be controlled and kept to the absolute minimum necessary for dealing with the incident;

(d)if it is necessary to evacuate all non-essential persons an attempt shall be made to ensure that contamination particularly on shoes or clothing, is not carried to other unaffected areas. If contaminated persons are evacuated they shall be monitored and measures to reduce surface contamination shall be taken as soon as possible;

(e)persons entering the affected area to carry out emergency procedure shall wear appropriate protective clothing;

(f)protective and, if possible, other outer clothing if contaminated with radioactive substances shall be removed and left in the affected area;

(g)decontamination of the contaminated persons shall be carried out as soon as possible; and

(h)appropriate radiation surveys shall be carried out.

(8)The following equipment shall be kept available for use in an emergency where appropriate—

(a)personnel protective equipment, including protective clothing, gloves, footwear and breathing apparatus;

(b)decontamination materials for the affected area including absorbent material for cleaning up spills;

(c)decontamination material for persons;

(d)cleaning equipment reserved for the purpose for cleaning in the active area;

(e)equipment for preventing entry into the affected area, including warning notices;

(f)equipment for the handling, temporary storage and disposal of contaminated articles;

(g)portable monitoring equipment including personnel monitoring devices;

(h)non-porous floor covering for example kraft paper (to be used only after any liquid spill has been cleared up);

(i)fire fighting equipment; and

(j)sundry items such as adhesive tape, labels, torch, notebook, pencils and simple first-aid equipment.

(9)After every accident the licensee and the person responsible for radiation safety shall carry out an investigation of the accident and a detailed written report shall be made on all findings, action taken, conclusions and recommendations for avoiding recurrence. This report shall be filed for future reference and a copy shall be sent to the Chief Radiation Protection Officer.

Part XI – Notification of accidents (regs 59-62)

59. Notification of accidents

The licensee shall be responsible for immediately notifying the Chief Radiation Protection Officer by telephone or telegraph of any incident involving any source of radiation possessed by him and which may have caused or threatens to cause—

(a)a dose to the whole body an individual of 0.25 g-rays (25 rads) or more of radiation, a dose to the skin of the whole body of any individual of 1.5 g-rays (150 rads) or more of radiation, or a dose to the feet, ankles, hands, or forearms of 0.75 g-rays (75 rads) or more of radiation; or

(b)release of radioactive materials in concentrations which, if averaged over a period of twenty-four hours will exceed 5,000 times the derived concentration limits specified for such materials; or

(c)a loss of one working week or more of the operation of any facilities affected.

60. Twenty-four hours notification

Each licensee shall within twenty-four hours notify the Chief Radiation Protection Officer by telephone or telegraph of an accident involving sources of radiation possessed by him and which have caused or threaten to cause—

(a)a dose to the whole body of an individual of 0.05 g-rays (5 rads) or more of radiation, a dose to the skin of the whole body of an individual of 0.3 g-rays (30 rads) or more of radiation, or a dose to the feet, ankles, hands, or forearms of 0.75 g-rays (75 rads) or more of radiation; or

(b)release of radioactive materials in concentrations which, if averaged over a period of twenty-four hours will exceed five hundred times the derived concentration limits specified for such materials.

61. Reporting of over exposures and excessive levels of concentration

(1)In addition to any notification required under regulations 59 and 60, each licensee shall make a report in writing within thirty days to the Commission of—

(a)each overexposure of an individual to radiation in excess of applicable limits provided for in the Schedule II;

(b)each overexposure of an individual to radioactive material in excess of the applicable maximum concentration limits given in Schedule II;

(c)levels of radiation or concentrations of radioactive material in excess of any applicable limit in the licence;

(d)any incident for which notification is required by regulations 59 and 60; and;

(e)level of radiation or concentrations of radioactive material (whether or not involving excessive exposure of any individual) in a restricted area in excess of ten times any applicable limit set forth in the part or in the licence. Each report required under this regulation shall describe the extent of each individual's exposure to radiation or to radioactive material including estimates of each individual's exposure as required by regulations 59 and 60, levels of radiation and concentrations of radioactive involved, the cause of exposure, levels of concentration, and corrective steps taken or planned to ensure against non-recurrence.

(2)Any report filed with the Commission pursuant to this regulation shall include for each individual overexposed, the identity card number, date of birth and an estimate of the individual's dose. The report shall be prepared so that this information is stated in a separate part of the report.

62. Notification and report to individuals

When a licensee is required pursuant to regulation 61 to report to the Chief Radiation Protection Officer about any exposure of an individual to radiation or radioactive materials, the licensee shall also notify the individual. Such notice shall be transmitted at a time not later than the transmittal time to the Chief Radiation Protection Officer.

Part XII – Vacating of the premises (reg 63)

63. Vacating of the premises

Each specific licensee shall, in not less than thirty days before vacating or relinquishing possession or control of premises which may have been contaminated with radioactive material as a result of these activities, notify the Chief Radiation Protection Officer in writing of intent to vacate. When deemed necessary by the Commission, the owner shall decontaminate the premises in such a manner as the Commission may specify.

Part XIII – Miscellaneous provisions (reg 64)

64. Compliance with regulations

(1)Each worker at risk of exposure to radiation must comply with all practices and regulations set out in this Code of Practice.

(2)The Radiation Safety Officer of each establishment using radiation shall be fully and solely responsible for the safe use of all radiation sources, isotopes and their safe disposal. He will also be responsible for instructing workers in the safe use of ionising radiation and must ensure that proper working techniques and safety precautions are observed.

(3)The Chief Radiation Protection Officer from the National Radiation Commission shall be authorised to inspect installations using radiation at any time and shall be given full facility and assistance by the head of the establishment where radiation is used and by the Radiation Protection Officer at that place.

(4)Radiation workers who will fail to use proper methods and to take adequate precautions shall be responsible for the consequences. The Commission's disciplinary Committee is authorised to make appropriate penalty to such persons.

(5)Conditions of employment and position of radiation workers shall be such as to attract and retain conscientious, responsible and well-trained staff. It is recommended to the employer that he gives incentives such as increased salary, special radiation allowance, reduced house rent, extra holidays and special diet, etc.

First Schedule

Forms

[Editorial note: The forms have not been reproduced.]

Second Schedule

The system of dose limitation

1.IntroductionThe detrimental effects against which protection is required are known as somatic and hereditary. Radiation effects are called "somatic" if they become manifest in the exposed individual himself, and "hereditary" if they affect his descendants."Stochastic" effects are those for which the probability of an effect occurring, rather than its severity, is regarded as a function of dose without threshold."Non-stochastic" effects are those for which the severity of the effect varies with the dose and for which a threshold may therefore occur. At the dose range involved in radiation protection, hereditary effects are regarded as being stochastic. Some somatic effects are stochastic; of these, carcinogenesis is considered to be the chief somatic risk of irradiation at low doses and therefore the main problem in radiation protection.The aim of radiation protection should be to prevent detrimental non-stochastic effects and to limit the probability of stochastic effects to levels deemed to be acceptable.The prevention of non-stochastic effects would be achieved by setting dose equivalent limits at sufficiently low values so that no threshold dose would be reached, even following exposure for the whole of a lifetime or for the total period of working life.The limitation of stochastic effects is achieved by keeping all justifiable exposure as low as is reasonably achievable, subject always to the boundary condition that the appropriate dose equivalent limits shall not be exceeded. For the above reasons, the International Commission on Radiological Protection (I.C.R.P.) recommended a system of dose limitation, the main features of which are as follows—

(a)no practice shall be adopted unless it introduction produces a positive net benefit;

(b)all exposure shall be kept as low as reasonably achievable economic and social factors being taken into account.

2.Radiological consideration and dose limitsThe relationship between the dose received by an individual and any particular biological effect induced by irradiation is a complex matter. I.C.R.P. recommended that regarding stochastic effects, there is within the range of exposure conditions usually encountered in radiation work, a linear relationship without threshold between dose and the probability of an effect.For the purposes of radiation protection it is necessary to specify a number of organs and tissues that have to be considered because of their susceptible to radiation damage. For protection purpose sufficient accuracy is obtained by using a single dose equivalent limit for each organ or tissue for all workers regardless of age or sex. These limits are based upon the average risk levels.The system of limitation includes justification of the practice, optimisation of radiation protection and recommendation of annual dose equivalent limits. The primary limit quantities are—The effective dose equivalent H(E)—For uniform as well as non-uniform irradiation of the whole body, in order to assess the risk of those effects of radiation exposure for all those organs for which proportionality between dose equivalent and probability of effect is assumed (stochastic effects); H(E) is defined as the sum of the risk weighted mean dose equivalents in relevant body tissues, i.e.Where H(E) is the sum of the weighted organ dose equivalent called the effective dose equivalent.W(T) is a weighting factor representing the fraction of risk resulting from tissue T when the whole body is irradiated uniformly, and H(T) is the annual dose equivalent in tissue T. The values of W(T) recommended by the I. C. R. P are—

Gonads	0.25
Breast	0.15
Red bone marrow	0.12
Lung	0.12
Thyroid	0.03
Bone surface	0.03
Remainder	0.30

Regarding the remainder, the I.C.R.P. recommends that a value of W(T) = 0.06 be applied to each of the five organs or tissues receiving the highest dose equivalent, and that the exposure of all the other remaining tissues may be neglected (stomach, small intestine, upper intestine and lower large intestine are to be treated as four different organs). The skin, lens of the eye, hands, forearms, feet and ankles are not considered in computing the effective dose equivalent.The dose equivalent H(T):In specific tissues or organs (T) i.e. the skin of the whole body, the lens of the eye and the extremities (including their skin) in order to assess the risk of those effects of radiation for which a threshold may exist (non-stochastic effects), H(T) is defined as the mean dose equivalent in the relevant tissue but in the case of skin, it is the average dose equivalent over a defined area.In order to specify acceptable limits for human exposures the I.C.R.P. introduced limits for primary dose quantities in specified tissues. The dose equivalent limits for workers are as follows—

(i)to prevent the occupance to non-stochastic effects a limit of 0.5Sv (50rem) in a year applies to all tissues except the lens of the eye, for which the recommended annual limit is 15Sv (15rem). These values apply irrespective of whether tissues are exposed singly or in combination with other tissues, and are intended to constrain exposure that fulfil the limitation for stochastic effects given below;

(ii)for stochastic effects, the quantity which is limited is the effective dose equivalent H(E) the annual limit being 50mSv (50rem).

The dose equivalent limits are not intended to be designing or planning objectives but are the lower boundary of a forbidden region of values. Values above the limits are specifically not permitted, but values below the limits are not automatically permitted. In this sense, the limits are the constraint for the optimisation procedures.The effective dose equivalent H(E) is essentially unmeasurable and, as a result is must be estimated on the basis of dose equivalents determined at appropriate locations in suitable receptors.The I.C.R.P. recommended two concepts for purposes of individual monitoring. The first of these concepts, the individual dose equivalent penetrating. Hp(d) is appropriate for deep organs which will be irradiated by strongly penetrating radiation. Hs(d) is suitable for shallow organs which will be irradiated by both weakly and strongly penetrating radiation. The recommended depth d for Hp is 10mm and Hp(d) may be written as Hp(10). The recommended depth d for Hs is 0.07mm and Hs(d) may be written as Hs(0.07); Hp(10) at a given location on the anterior portion of the trunk can be related to the H(E) received by the trunk for radiation incident from anteriorly to laterally on the body, (annual dose limit 50 mSv). Also, a dosimeter indicating Hs(07) will usually provide an adequate estimate of the dose equivalent to the exposed skin (the annual limit for any small area of skin is 500 mSv). In most exposure conditions, the dose equivalent limit for the lens of the eye will not be exceeded when the limits for the effective dose equivalent and the dose equivalent to the skin are not exceeded.Internal exposure resulting from the intake of radionuclides can be based on annual limits of intake (ALI) which, for some of the radionuclides are mentioned further.The dose equivalent for the prevention of non-stochastic effects is the sum of any dose equivalent in a particular organ or tissue from external exposure during a year and the committed dose equivalent from any intake of radionuclides to that organ or tissue during that year.The dose equivalent for the control of stochastic effects is the sum of any effective dose equivalent for external exposure during a year and the committed effective dose equivalent from any intake of radionuclides during that year.Summation of internal and external exposure is performed by reference of such exposure to the two secondary limits for external exposure, i.e. the annual limits for the 10mm and the 0.07mm dose equivalents and the secondary limit for the intake of radionuclides, i.e. The Annual Limit of Intake (ALI);

2.Where Hp(10) is the annual dose equivalent recorded for body exposure of deep lying organs, H(0.07) is the annual dose equivalent recorded for skin exposure, H(E,L) is the annual effective dose equivalent for workers (50mSv), H(sk,L) is the annual dose equivalent limit for the individual organs and tissues for workers (500 mSv), Ij is the annual intake of radionuclide j and Ij, L is the ALI for radionuclide j. Compliance with primary limits is achieved if neither of these expressions exceeds one unit.THE IAEA PUBLICATION SAFETY SERIES No. 9"Basic Safety Standards for radiation protection" 1982 Edition included in Annex III are the Annual Limits on Intake (ALIs) and derived air concentrations (DACs) of all radionuclides for occupational exposure. This publication is available in the National Radiation Commission Library and the Chief Radiation Protection Officer (CRPO) will use these recommendations before the licence is given for application of open radionuclide sources.

Third Schedule

Types of radiation and primary dose quantities

1.Alpha particlesAlpha particles are helium nuclei emitted mainly by heavy radionuclides such as polonium, radium, thorium, uranium, etc. They have well defined and characteristic energies and as they are doubly charged and move relatively slowly, they are densely ionising and thus, in spite of their high energies, their penetrative power or range is extremely limited. In fact, alpha particles of energies up to 7.5 MeV are incapable of penetrating the protective layer of skin on most parts of the body. Their range in air is only a few centimetres. Thus, shielding against this type of radiation presents no problem, but hazard from ingestion or inhalation into the body of alpha radioactive materials is great.

2.Beta particlesBeta particles are high-energy electrons created and emitted by certain radionuclides. Beta particles are emitted in a continuous energy spectrum and hence tables of beta energies always list the maximum energy of emission which is characteristic for each radionuclide. Beta particles loose energy mainly through ionisation, but may also loose energy by the production of bremsstrahlung (Braking radiation). For a given energy, beta particles have a much greater range than alpha particles. In addition because of their small mass, beta particles undergo frequent scattering with little loss of energy, a process analogous to reflection form surfaces, and referred to as backscattering.The extent of backscattering increases with the atomic number of the surface material from which it is reflected. Thus in the design of shielding for pure beta emitters particular attention should be paid to the possible production of bremsstrahlung.

3.ProtonsProtons are hydrogen nuclei and are therefore positively charged. Proton beams are produced in accelerators of different types and may have energies of several hundreds of MeV. Protons are also emitted in the interactions of fast neutrons with hydrogen atoms.

4.NeutronsThe neutron is an uncharged particle having a mass slightly higher than that of a proton. Neutrons are generally classified according to their energies under four broad categories.

(a)Thermal neutronsare those which are in thermal equilibrium with the surrounding matter. These neutrons will have most probable velocity of 2.3 x 10⁵cm/s corresponding to kinetic energy of 0.025 eV.

(b)Intermediate neutronsare those falling in the energy range of 0.5 cV to KeV. Neutrons having energies less that 100cV are also referred to as slow neutrons.

(c)Fast neutronshave energies between 10 KeV and 10 MeV.

(d)Relativistic neutronshave energies greater than 10 MeV. The interaction of neutrons with matter is quite different from that of either charged particles or gamma rays. Depending on their energy neutrons, interact with matter by various processes—

(a)Elastic scattering.

(b)Inelastic scattering.

(c)Capture.

(d)Particle emission.

(e)Fission.

Essentially the absorption of neutrons occurs in two stages: Fast neutrons are slowed down by elastic and inelastic scattering processes with nuclei, particularly light nuclei such as carbon and hydrogen. The slowed-down neutrons are then captured. The capture cross-section for low-energy neutrons is high for most elements.

5.X- and gamma raysX - and gamma rays are electro-magnetic radiation of very short wave lengths. There is no difference between them except in their origin. Gamma rays are emitted with discrete energies characteristic of the nuclei. X-ray emission is of two types: characteristic radiation (discrete energies) and bremsstrahlung (continuous spectrum energies).There are a number of ways in which electro-magnetic radiation may interact with matter producing electrons and protons with lower energies (photo-effect and co-emption effect).

Primary dose quantities and units:

1.Exposure (X)The exposure X, is the quotient of dQ divided by dm where the value of dQ is the absolute value of the total charge of the ions of one sign produced in air when all the electrons and/or positrons liberated by photons in air of mass dm are completely stopped in air:X = dQ/dmUnit: Coulomb per kilogram (C/kg)In practice, the former special unit roentgen (R) is still sometimes used.1 R = 2.58 x 10⁴ C/kg (exactly).

2.Absorbed dose (D)As defined by I.C.R.U., the absorbed dose (D) is the quotient of dE divided by dm, where dE = 0.01g-ray (Gy); 1Gy = 1J/kg. (The old unit of absorbed dose is the rad:1 - rad = 10^-2J/kg.)The absorbed dose (D) is the most important physical quantity employed to specify the irradiation of biological material. However, the relation between a given biological radiation effect and absorbed dose will change when the type of radiation or other conditions are varied.

3.Kerma (K)Kerma is an abbreviation for kinetic energy released in material and is defined by the quotient:K = dE(tr)/dmWhere dE(tr) is the sum of the initial kinetic energies of all the charged ionising particles liberated by the uncharged ionising particles in a material of mass dm. The quantity dE(tr) includes the kinetic energy expended by these charged particles in collisions and the energy radiated as bremsstrahlung and also the energies of any secondary charged particles such as the delta radiations produced within the volume element. In a situation where charged particle equilibrium exists at the point of interest and the bremstrahlung losses are neglible, kerma is approximately equal to the absorbed dose at the point. Kerma is slightly less than the absorbed dose when there is a transient charged particle equilibrium in beams of moderately high-energy X-rays or gamma radiation or neutrons.

4.Dose equivalent (H)All ionising radiations can produce the same kind of biological effect. However, certain radiations are more effective than others per unit absorbed dose. This means that a smaller absorbed dose of such radiations is required to produce a given degree of effect because the biological effect appears to depend upon the spatial distribution of the energy released along the track of the ionising particle. Generally the effect of radiation on a cell structure increases with increasing energy loss per unit path length (linear energy transfer LET), although certain single-hit effects such as the inactivation of bacterial and viruses, become less efficient per unit energy absorbed as the LET increases. The RBE (relative biological effectiveness) is defined as follows—RBE = Absorbed dose due to 250kV X-rays causing a specific effect, divided by the Absorbed dose due to other radiation causing the same effect, e.g. Dx-rays/DNeutrons = RBE. The use of the term RBE both in radiobiology and Radiation protection presented certain problems, so the International Commission of Radiation Units and measurements (ICRU), recommended that the term RBE be used in radiobiology only. For radiological protection purposes a separate term, the quality factor (Q), is used which depends on the linear energy transfer to charged particles. The relationship between the linear energy-transfer coefficient (L(oo)) and the quality factor (Q) is the following.

L(oo) in water	Quality factor
(keV. per micrometer)	Q
3.5 or less	1 X-and Gamma rays
7	2 Thermal neutrons
23	5 Epithermal neutrons
53	10 Neutrons and protons, etc.
175 and above	20 Alpha and other multiply charged particles.

The absorbed dose (D) can be weighted by a number of dimensionless factors (N) in such a way that the resultant quantity correlates with the magnitude or the probability of a biological effect. The dose equivalent (H) is defined by the equation:H = DQNAt present, N is taken to be equal to 1 for irradiation by external sources. The dose equivalent has the same dimensions as the absorbed dose but it is not the same quantity. The special unit of H is the sievert (Sv); 1Sv = 1J/kg. (the old unit of dose equivalent is the rem):1rem = 10²J/kg.The relationship between Q and L recommended for radiation protection is given in the above mentioned table.

5.Dose equivalent in specified tissues or organs (H(T))The dose equivalent H(T) in specified tissues or organs is the mean dose equivalent in the relevant tissue or organ. In the case of skin it is the average dose equivalent over a defined area.With respect to the I.C.R.P. system of dose limitation, the specified tissues are the skin, the lens, the eye and the extremities.

6.Effective dose equivalent (H(E))This unit is defined in Schedule II Part X.

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31 July 2002 this version

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01 January 1991

Commenced