The University of Reading Safety Guide 18

Ionising Radiation Health & Safety

Acquisition and disposal of radioactive materials

The University of Reading

Safety Guide 18 The University of Reading Safety Guide 18 Acquisition and disposal of radioactive materials 1 INTRODUCTION...... 1 2 GENERAL POINTS...... 1 2.1 Definition of "radioactive substance"...... 1 2.2 Forbidden materials...... 1 2.3 Exemption Orders...... 2 2.4 Uranium inventories...... 2 2.5 Certificates of Authorisation...... 2 2.6 Best Practicable Means, BPM...... 2 2.7 School records...... 3 2.8 Security...... 3 2.9 Planning and paying for disposal...... 3 2.10 Transferring radioactive materials to other workplaces...... 3 2.11 Biological and chemical hazards...... 4 3 ACQUIRING CLOSED SOURCES...... 4 4 DISPOSING OF CLOSED SOURCES...... 4 5 ACQUIRING OPEN SOURCES...... 4 5.1 Commercial sources...... 5 5.2 Non-commercial sources...... 5 5.3 Nomenclature...... 5 5.4 Order validation and forwarding...... 5 5.5 University Source Numbers (USNs)...... 5 5.6 Delivery dates...... 5 5.7 Source identification and labelling...... 6 5.8 Miscellaneous ordering aspects...... 6 6 DISPOSAL OF OPEN SOURCES...... 7 6.1 BPM, Best Practicable Environmental Option [BPEO] and waste disposal...... 7 6.2 Disposal returns...... 7 6.3 Inter-School returns and collation...... 8 6.4 Disposal of radioactive solids...... 8  Additional statement on VLL Waste...... 9 6.5 Disposal of radioactive liquids...... 11 6.6 Disposal of radioactive gaseous waste...... 11 6.7 Storage of radioactive wastes...... 12 6.8 Summary of disposal procedures...... 13 7 OPEN SOURCE STOCK CONTROL...... 13 8 TRANSPORT...... 14 9 REFERENCES...... 14 10 ACRONYMS...... 15

UNIVERSITY OPEN SOURCE STOCK AND DISPOSAL LIMITS SG18 Appendix 1....1 1 MAXIMUM OPEN SOURCE STOCK PERMITTED AT WHITEKNIGHTS.1 2 SCHOOL OPEN SOURCE ALLOCATIONS...... 1 3 MAXIMUM DISPOSALS PER MONTH...... 1 3.1 Solid waste (BIN/SKIP)...... 1 3.2 Aqueous waste (SINK)...... 1 3.3 Organic scintillant (DRUM)...... 2 3.4 Gaseous waste (ATMOSPHERE)...... 2 3.5 Other solid waste...... 2 Acquisition and disposal of radioactive materials ______4 STORAGE FOR DECAY OR COLLECTION...... 2 4.1 Aqueous waste: up to 900 days (30 months)...... 2 4.2 Organic scintillant – up to 540 days (18 months)...... 2 4.3 Solid waste: up to 900 days (30 months)...... 2 5 USE AND DISPOSAL at other University premises...... 3

Malcolm Iosson University Radiation Safety Officer Extension 8887

Fifth Edition – as amended 12 April 2005 The University of Reading Safety Guide 18 Acquisition and disposal of radioactive materials

1 INTRODUCTION This Safety Guide has been prepared to assist School Radiation Protection Supervisors (SRPSs) and radiation workers to acquire and dispose of radioactive materials in a manner which is safe, complies with The Ionising Radiation Regulations 1999 (IRR) (References 1 and 2), and is within agreed limits authorised by the Environment Agency under the Radioactive Substances Act 1993 (see below).

If in any particular case the Guide appears to conflict with the Regulations the latter must be followed and the University Radiation Safety Officer (URSO) (extension 8887) informed of the apparent contradiction.

Authority to acquire and dispose of radioactive materials at workplaces is governed by The Radioactive Substances Act 1993 (RSA) (Reference 3). This Act is enforced by the Environment Agency (EA). The University has authorisations under the Act to keep and dispose of the quantities of radioactive materials listed in Appendix 1. Exemption Orders (Section 2.3) are listed in References 4 - 13.

Other aspects of using radioactive materials and radiation generators (including non-ionising radiation) are given in Safety Guides 16, 17, 19, 20, 21, and 22. Further advice can be obtained from the SRPS (see the SRPS Contact List), who will if necessary consult the URSO. Purchasing orders for radioactive materials can be placed and disposals arranged only with the consent of the SRPS. See also Section 5.

2 GENERAL POINTS Before proceeding to the acquisition and disposal of radioactive materials the following general points should be noted.

2.1 Definition of "radioactive substance" The term “radioactive substance” is defined in IRR as “any substance which contains one or more radionuclides whose activity cannot be disregarded for the purposes of radiation protection” – i.e., any substance that could pose a radiation risk. As theoretically, any radionuclide could pose a radiation risk to an individual, this could be interpreted as meaning that the Regulations apply to any work involving a substance containing a radionuclide. Similarly, no minimum activity exemption is granted under RSA with the exception of specified (naturally radioactive) elements, such as Uranium, Radium or Radon, where minimum activity levels do apply..

2.2 Forbidden materials The University's registration forbids the disposal of any waste open sources containing strontium- 90 or any radionuclide which emits alpha particles. Before work with any such substances can commence it is essential to inform the URSO, so that he can consult with the EA. Application fees to change the Authorisation must be paid by the School concerned at the time that an application is made. ______April 05 SG18(1) Acquisition and disposal of radioactive materials

2.3 Exemption Orders Several Exemption Orders have been made under RSA relating to phosphatic substances, rare earths, uranium and thorium, prepared uranium and thorium compounds, geological specimens, waste closed sources, electronic valves, smoke detectors, gaseous tritium light devices, luminous articles and testing instruments (References 4 - 13). Consequently it is not necessary to regard limited quantities of natural uranium (< 2 kg.) and thorium compounds as open sources that must be registered with Health & Services (Sections 5, 6 and 7). However, such substances must still be handled according to the requirements of IRR to protect against any associated radiation hazards. Note that the Exemption Order for Uranium and Thorium compounds specifies that such compounds are “natural”, i.e., composed of the different isotopes of the element in their natural abundance. Technically, therefore, any Uranium compound prepared from depleted Uranium [“DU”, i.e., depleted in 235U ] does not comply with the Exemption Order. The EA have been asked for guidance on the application of the Order to compounds prepared from DU, but have yet to respond. See also Safety Note 7 [New] – “The use of Uranyl Acetate in electron microscopy”.

2.4 Uranium inventories A Euratom directive (Reference 14) governs the keeping of uranium and similar fissile materials, such as thorium, etc. If The University begins keeping significant quantities of these materials (> 2kg.) it must account (to the nearest milligram) for all Uranium etc, at The University. This is not a safety requirement but a security feature to preclude the possibility of accumulating potential bomb materials. Consequently if any member of The University should acquire Uranium, etc, for a research programme, then he or she will have to carry out a survey of all such materials at The University, send details to a national stock-taking point, periodically update the material in the light of future acquisitions and disposals, etc. Due to the overwhelming administrative procedures any member of The University contemplating such work - who will have to personally arrange and carry out all the required procedures - must discuss the proposal with the URSO before work commences. See also Safety Note 7 (New) – the Use of Uranyl Acetate in Electron Microscopy.

2.5 Certificates of Authorisation Copies of the relevant Certificates of Authorisation issued by the Environment Agency (which remain valid until replaced) must be displayed on Health & Safety Noticeboards (Safety Guide 2) of departments using radioactive materials. Copies are available from the URSO. A key-point summary is given in Appendix 1.

2.6 Best Practicable Means, BPM One of the conditions now applied to the Certificate of Authorisation to dispose of radioactive waste is that “best practicable means” are used to manage the use of radioactive substances, and to minimise the disposal of radioactive substances into the environment.

BPM may be defined as “The level of management and engineering control that minimises, as far as practicable, the release of radioactivity to the environment”. There is an obligation to take into account cost-effectiveness, technological developments, operational safety, social and environmental factors, but the organisation is not expected to spend money, time or trouble that is disproportionate to the likely benefits.

EA Inspectors may request to see a BPM Policy Statement for the University, and examine evidence and /or inspect the University in respect of conformity with the Statement. The Policy

______SG18(2) April05 Acquisition and disposal of radioactive materials

Statement may be regarded as equivalent to the Health and Safety Policy Statement of the University, and, like that statement, the detailed policy is by reference to the University Safety Guides relating to the use of radioactive materials (Safety Guides 16 and 19, in addition to this Guide), and to any Local Rules or Systems of Work applicable to such use. See section 6 for details of the application of BPM to waste disposal.

2.7 School records Local School records of radioactive substances must be maintained, and monthly updates of disposals sent to the Radioactive Materials Stock Co-ordinator (School of Animal and Microbial Sciences, extension 7043). Copies of the monthly disposals and stock level records are kept by Health & Safety Services (Section 7).

2.8 Security Conditions of the University's EA registration certificates are:  competent persons must be made responsible for sources, wastes, etc;  all radioactive materials are either under immediate close supervision or locked away in a secure place;  radioactive materials must not be stored with or close to any readily flammable or explosive materials;  any loss of radioactive materials must be reported to Health & Safety Services and to the Police, and all reasonable steps taken to recover the missing materials; and  loan or hire of radioactive materials is not permitted. (But materials may be donated to other organisations which have the appropriate authority to hold them.)

2.9 Planning and paying for disposal The method(s) for disposal must be agreed before any radioactive waste can be produced. Some disposal methods are very expensive; users must ensure that they are adequately funded to pay the costs involved before acquisition. Advice on these aspects must be sought from the URSO (extension 8887) at the planning stage before work begins. A high charge is made by the EA for any change in the University's authorisations.

2.10 Transferring radioactive materials to other workplaces Radioactive materials can be transferred to other workplaces. If, for example, members of The University of Reading move to other universities and wish to take their sources with them, then providing the recipient workplace(s) has appropriate RSA registration certificates and formally indicates in writing to the SRPS of the donor School (who must copy the correspondence to the URSO) that they are willing to accept the materials concerned, the sources can be transferred. The University records (Section 7) will then be modified accordingly. It should be noted that transfers of this nature are not a method of disposal. There is no special EA Form to cover these circumstances. Transportation aspects are described in Safety Guide 16 (Section 12), and Safety Note 8 “Transport of radioactive materials by road.”

2.11 Biological and chemical hazards This Guide refers only to the radioactivity of materials; due consideration must be given to any associated biological, chemical and/or other hazards. Acquisition and disposal of radioactive materials

3 ACQUIRING CLOSED SOURCES A closed source may take the form of a radioactive substance encapsulated, for example, between sheets of plastic. Certain foil sources are also classified as "closed". The term "sealed source" is, speaking strictly, confined to sources sealed by welding inside a stainless steel case. A sealed source is, by definition, also "closed"; but a closed source need not be "sealed". Note that certain instruments may include closed radioactive sources for calibration or detection purposes – these must also be notified to the URSO before acquisition.

A “suitable and sufficient” risk assessment must be carried out before acquiring any new radioactive source, and a copy of the assessment supplied to the URSO with the request to acquire the source.

In compliance with the twin principles that exposure to ionising radiation should be “as low as reasonably practicable” (ALARP) and that holdings of radioactive materials be minimised, the holding of any radioactive source must be capable of being justified to an Inspector from the EA. Production of a copy of the required risk assessment should assist in the justification process, since the assessment should be used as a means of minimising the risks of using or storing any radioactive material

The proposed acquisition of a “new” closed source must be notified in writing to the URSO, and must include a copy of the risk assessment (see above).

A list of closed sources and associated University Source Numbers (USNs) is maintained by Health & Safety Services. Closed sources must not be mutilated in any way.

4 DISPOSING OF CLOSED SOURCES Members of The University wishing to dispose of closed sources must consult the URSO well in advance of the proposed disposal, as disposal of even low activity closed sources is a lengthy and costly process. When sufficient demand arises, or the number of redundant sources warrants it, a central collection may be made, and the sources transported to an authorised agency, eg Safeguard International. The costs involved will be apportioned according to the original owner Schools of the sources sent for disposal.

In some instances the suppliers of instruments containing closed sources, liquid scintillation counters for example, may take the source back for refurbishment. The charges involved are usually only a small fraction of those incurred for disposal.

5 ACQUIRING OPEN SOURCES The following points must be followed to acquire open (ie unsealed) sources.

5.1 Commercial sources All commercial open sources for Whiteknights must be ordered via the Radioactive Materials Purchasing and Stock Co-ordinator (RMPSC) in the School of AMS (extension 7043 or 7025). Orders must not be sent directly to the central University Purchasing Office: such orders will be rejected and returned to the originating Department or School, and will consequently be delayed.

5.2 Non-commercial sources Anyone proposing to acquire a "non-commercial source" (eg a specimen obtained from another research establishment) must discuss the proposal with the Radioactive Materials Stock Co- ordinator (extension 7043) to ensure that the activity of the source is within the authorised limits for the campus (Appendix 1) once current holdings are taken into account. If permissible, the RMPSC will issue a University Source Number (USN – see below) to the material on receipt.

5.3 Nomenclature Order forms should be completed using the nomenclature used in the "Amersham Research Products" catalogue where applicable.

5.4 Order validation and forwarding When an order has been entered satisfactorily into the AMS computer, which checks that the quantity ordered is within the authorised limit for The University (Appendix 1) with current holdings taken into account, the official order will be sent via the University Purchasing Office to the supplier nominated by the person requesting the source. Simultaneously an "Order Forwarded" form will be sent to both the person requesting the source and the SRPS. If the order exceeds the authorised limits it will be returned to the person ordering the source with suggestions regarding amendments.

Total activity limits for each radionuclide apply to the whole of Whiteknights. The division of the total activity between departments is the result of agreement between the SRPSs concerned - the URSO may be called on to arbitrate if problems arise. The division of the allotted activity within a School is the responsibility of the SRPS.

5.5 University Source Numbers (USNs) The "Order Forwarded" form bears a unique University Source Number (USN) that must be used in all future correspondence. This number must be permanently applied to the container of the material when it arrives, and also on the containers of any aliquots taken from the source. There must be a proper audit trail linking all of the material to records of use and disposal – see section 5.7.

5.6 Delivery dates Upon delivery of the source to the School the recipient must enter the date of delivery on the tear- off portion of the Order Forwarded form and send it to the Radioactive Materials Purchasing and Stock Co-ordinator (AMS). The SRPS or alternate should also be informed that the source has arrived.

The date of delivery of non-commercial sources (section 5.2) is assumed be the date given on the Request Form.

5.7 Source identification and labelling The USN is the only way that the computer can recognise a particular source. It is strongly recommended that source containers are labelled with the USN immediately upon receipt and that aliquots and sub-aliquots are numbered with respect to the parent USN. For example, USN 101 would be divided into aliquots 101/1, 101/2 ... 101/x and sub-aliquots of aliquot 101/2 would be labelled 101/2/1, 101/2/2 ... 101/2/y and so on.

The adoption of this standard system is unambiguous, easier than writing long chemical and/or isotope names on containers (many of which are small in size), and permits recognition of a Acquisition and disposal of radioactive materials

particular source by any member of The University with respect to the USN. Details of all open sources are stored as a permanent record in the computer. School record keeping systems, research notebooks, etc should also operate using the USN.

5.8 Miscellaneous ordering aspects  Telephone orders Orders can be made by telephone only when absolutely necessary, for example to synchronise maximum activity with experimental schedules. The procedure is not to be used as a matter of course.

The Radioactive Materials Purchasing and Stock Co-ordinator (RMPSC) in the School of AMS (extension 7043 or 7025) or in their absence the SRPS for the School of AMS (see the SRPS Contact List) must be contacted before telephoning the supplier, to ensure that authorised limits on activity are not exceeded. An Order Form must be completed and a USN allocated before the source is received.

 Bulk purchases and standing orders Persons wishing to place bulk purchases to take advantage of quantity discounts with periodic delivery of components items according to user(s) requirements must obtain approval beforehand. Advance USNs will be allocated. Dates of delivery must still be notified by the person responsible for each source when it is delivered according to demand (Section 5.6).

 Inter-School transfers A list of current holdings of open courses relating to isotope, compound, activity, person responsible for the source, etc is available from the Radioactive Materials Purchasing and Stock Co-ordinator (RMPSC) in the School of AMS (extension 7043 or 7025). However, before any material is transferred to another user in a different School, a new USN must be issued and a record made of the transfer by the donor.

6 DISPOSAL OF OPEN SOURCES

6.1 BPM, Best Practicable Environmental Option [BPEO] and waste disposal The fundamental requirement of BPM is that the release of radioactivity to the environment is minimised, as far as reasonably practicable. To achieve such a minimisation involves choosing the Best Practicable Environmental Option (BPEO). Given that the use of open sources of radioactive material has been justified, the BPEO should be chosen that minimises both the risks to the user(s), and the risks to “other persons “ who may be exposed to the activity once it has been “released to the environment” – i.e., disposed of.

 Identification of the BPEO is a risk-balancing exercise, and would be required at the point of either applying for a Certificate to discharge or dispose of radioactive waste, or applying for a Variation in such a Certificate. As such, it would include a Environmental Impact Assessment, and is not an exercise to be entered into lightly. The University’s current Certificate was issued in 2000, and is unlikely to be amended in the near future, so undertaking the procedures to identify the BPEO for waste disposal is not likely to be formally required for some time. However, it should be remembered that the use of BPM/ BPEO is a continuing obligation, and the routes of, and techniques adopted for waste disposal must be kept under review.

 Factors that need to be borne in mind when considering the BPEO include the possibility of “decay storage” for short-lived isotopes. Here, the risks of storage [to the individuals who may have to enter the store, and be exposed to the radiation from the stored waste] are balanced against the risks of disposal “to the environment” – for example, if liquid aqueous waste is disposed of to drain, the activity will be greatly diluted and removed from the premises. However, people such as sewage workers will then be exposed to the radiation (albeit doses will be extremely small) when storage on the premises would have prevented their exposure. If the activity is incorporated into organisms in the food chain, and ends up in fish, which are then eaten, those persons who eat the fish will be exposed to a dose of radiation that they would otherwise not have been exposed to. (Note that the University is already permitted to use decay storage for both solid and aqueous waste labelled with short-lived isotopes such as 32P and 125I.)

 A more detailed appraisal of BPM/ BPEO is available on request from the URSO.

6.2 Disposal returns As a statutory requirement a full statement of disposals from open sources by all routes must be compiled every month. The SRPS of each user School must make a monthly return to the Radioactive Materials Purchasing and Stock Co-ordinator (RMPSC) in the School of AMS (extension 7043 or 7025) on a standard form, listing the activity disposed of (in Becquerels and/or microCuries) from each USN. Each method of disposal, eg, "bin", "sink", and the activity deposited in the store, must be recorded separately. Correction for decay must not be made (see example below).

When the final aliquot of an open source has been disposed of the USN should be encircled on the monthly disposals form, so that it can be deleted from the inventory. Nil returns are required if no disposals have been made during the previous month.

Disposals do not need to be corrected for decay - the computer does this automatically - but must be quoted as a fraction of the original quantity (activity) of material. Acquisition and disposal of radioactive materials

 Example For example, if you received delivery of a 3.7 MBq/ 0.1 ml open source and used/ disposed of 10 l of the original amount during the accountancy month, all you need quote with regard to the parent USN is 0.37 MBq (370 kBq) and disposal route. In some cases, the disposal quantities by specific routes are arrived at by calculations based on assumptions made of the uptake or distribution of the material in an experiment. If this situation applies, a “best estimate” should be used to arrive at the figures.

Similarly, if you make a second disposal of 1/10th of the original source in two months time, you will still quote 1/10th even if the isotope has a short half-life and has decayed significantly.

 Cautionary notes When completing the Monthly Disposal forms:  enter the dates of disposal in a legible manner, with accuracy and care;  include only disposals made during the period requested;  quote Area/School as cited when the open source concerned was ordered and the USN allocated;  quote exact dates (DD/MM/YYYY) (not periods) for total daily disposal to the final disposal point (ie "bin/skip", "drum", "sink", "other", etc) for each USN;  encircle the USNs when the sources - including all aliquots - are completely exhausted;  quote quantities as "fractions" of the original quantity obtained (do not correct for decay - see above example) – note that for some routine processes the allocation of radioactive waste between the various routes is performed by the computer software; and  indicate the route of "authorised" disposal transfers outside The University.

6.3 Inter-School returns and collation "Monthly Disposals" forms must be signed by the SRPS or alternate. In areas where there are several research groups using open sources it is acceptable if a "Monthly Disposals" form from each group is checked and forwarded by the SRPS after all the sheets from the groups in his School are collated, numbered and the top sheet signed by the SRPS. This measure saves the SRPS having to copy the information from the group forms to one School form.

6.4 Disposal of radioactive solids Apart from articles or substances to which an Exemption applies (see below), the only route available for the disposal of solid waste is that of “Very Low Level (VLL)” waste (see below), i.e., waste to which specific activity limits apply. Higher activity waste cannot be disposed of by this route, although the University is permitted to accumulate and store such waste for up to 30 months, provided that: a) the half-life of the radionuclides concerned is less than 3 months; b) the total activity is less than 520 MBq [14 MCi], and c) the total volume of the accumulated waste is less than 6 m3 The effect of these limitations means that, apart from short-lived isotopes, the University has no authority to dispose of radioactive solid waste other than via the VLL route. The concession of storage for short-lived isotopes will permit approx. 10x half-life decay or more, depending on the half-life, allowing the initial activity to decay to below 1/1000 of the initial activity. In most cases, this will permit disposal via the VLL route (see below.)

Solid waste not complying with the requirements for the VLL route would require the University to apply for a Variation of its waste disposal certificate, and would require a new Environmental Impact Assessment; justification of the proposed practice, changes to the BPM statement and demonstration that this would be the best practicable environmental option. A fee – payable by the School or Department requesting this facility – would be charged by the Environment Agency. As previously indicated, changes to the Certificate are costly, and take several months to effect, so research supervisors are urged to examine their practices very carefully to avoid the need for disposal of “non-VLL” waste by an authorised collector. See additional statement on VLL waste disposal, below.

 Exemptions Exemption orders have been made regarding the disposal, under certain conditions, of limited quantities of uranium and thorium or their compounds (Reference 5 & 6 – see also Safety Note 7(New)), smoke detectors (Reference 10), particular types of closed sources (Reference 8) and geological specimens (Reference 7). The URSO (extension 8887) must be consulted before disposing of these items.

 “Very Low Level (VLL)” waste disposal – i.e., dustbin and skip disposal Small amounts of solid waste, excluding alpha emitters and strontium-90, are authorised for disposal with ordinary refuse. The limits for such dustbin disposals are:  400 kBq (~ 11 mCi) in any 0.1m3 (roughly equivalent to an ordinary dustbin); and  40 kBq (~ 1.1 mCi) per single article. Note that the limits are 10 times higher for 14C and 3H disposals. VLL waste must be disposed of within 14 days of production, and not accumulated within the laboratory. Note however that the University authorisation includes permission to store solid waste for up to 10 half-lives for isotopes with a half-life of 90 days or less. This facility would allow “decay-storage” for contaminated items that could not be disposed of by the VLL waste route at the time of production – for example, contaminated tissues that had been used to clean up a minor spill of a short-lived isotope.

 Additional statement on VLL Waste Note: Since the Fifth Edition of this Guide was completed, (November 2004) essential changes to the procedures for disposal of VLL waste have been implemented. These changes were required because it was discovered that Grundon (who operate the skip collection and disposal system used for general waste within the University) were operating a materials recovery and recycling process from the general waste; this included sorting discarded items by hand for recovery of items such as plastics, etc. The terms of the VLL waste authorisation require that “materials go directly to landfill”. To avoid contravention of this requirement, VLL waste should no longer be placed in the green skips.

At present, the solution to this problem is for all VLL waste to be collected and transported to the London Road site (see below for transport arrangements), where the waste collection is operated by Reading Borough Council (RBC). Currently, their waste goes directly to landfill, and complies with the authorisation. However, if RBC change their system to include a materials recovery process, this route will cease to be available. This would then require the University to apply for/ acquire an authorisation to dispose of solid waste by another route – probably by incineration. The costs of such a change would inevitably fall on the authorised users, and are likely to add significantly to the costs of using open sources within the University.

 Removal of identifying marks Acquisition and disposal of radioactive materials

All identifying marks or numbers and indications of radioactivity must be removed from items before disposal. Radioactive symbols must be removed or obliterated from all cans or packaging material before dustbin disposal to allay unnecessary fears from those who handle the refuse. See Section 6.6 for labelling requirements.

 Contaminated disposables Disposable articles, such as tissues, razor blades, syringes and glass or plastic laboratory vessels should not be accumulated. Once the overall activity level (Appendix 1) has been checked they can be disposed of in designated “VLL waste bags” for transport to the London Road site. Any items that could be possibly attractive as salvage should be destroyed before disposal. Note that any “sharps” that may be contaminated by microorganisms must be rendered safe (from both a microbiological and a radiological aspect) before disposal. They should be decontaminated by soaking in an appropriate disinfectant, and rinsed with water (with both used disinfectant and rinsings being discarded as radioactive liquid waste) before being sent for incineration as non-radioactive waste.

 VLL waste transport arrangements At the time of writing, bags of VLL waste are transported to the London Road site by University transport. Contact the RMPSC (ext. 7043) for details.

 Disposal by incineration The University does not have any incineration facilities, nor an authorisation to dispose of radioactive waste by such means. Individual workers therefore must not arrange to transport radioactive waste from The University for incineration elsewhere. Authorisation for incineration may be possible, but the procedure is lengthy, and attracts an expensive application fee, payable by the School generating the waste. Any proposals to initiate procedures that would require incineration (e.g., of radioactively contaminated animal carcasses) must be discussed with the URSO (in collaboration with the URPA) well in advance.

 Disposal by authorised agents This route presently only applies to accumulated organic liquid waste, i.e., liquid scintillant waste. The URSO must be consulted and the waste must be stored in a safe place whilst awaiting disposal (Section 6.6), in a labelled container of adequate strength. The RMPSC currently manages the collection and disposal system for liquid scintillant waste produced in AMS, and should be contacted by the SRPS of any other School liable to produce scintillant waste. The volume of waste must not exceed 1 m3 [1000 litres], and the storage period must not exceed 18 months.

 Carcass disposal by burial or maceration Neither of these routes is now permitted at the University. Disposal by burial is not permitted until special EA authorisation has been obtained. Changes by Thames Water mean that remains of small animals can no longer be disposed of by maceration and flushing down the drains.

6.5 Disposal of radioactive liquids  Aqueous solutions Radioactive aqueous solutions can be flushed down normal laboratory drains following dilution. An adequate quantity of water must be allowed to flow through the drain to minimise retention in U-traps. The maximum amount of activity that The University is authorised to dispose of via sinks in one month is given in Appendix 1. Only appropriately labelled stainless steel sinks may be used for disposals.

Aqueous waste containing short-lived isotopes may be accumulated for up to 30 months before disposal down the drain. (See Appendix 1)

Any person intending to start a programme involving the production of appreciable quantities of radioactive aqueous solutions must discuss the problems that may arise with the SRPS - who will, when necessary, seek advice from the URSO.

 Organic liquids The following points should be borne in mind regarding the disposal of organic liquids:  Thames Water forbid the disposal of "Ecoscint" and other biodegradable scintillator fluids by pouring down laboratory sinks;  dilution is not a permitted method of disposal; and  The University does not have direct access, or permission for access, to any incinerator approved for the disposal of organic liquids.

Radioactive scintillator fluid or organic solvent waste must be disposed of as radioactive waste by removal through an authorised agent. There are two named authorised agents on the Certificate - Shanks Chemical Services Ltd, and S. Grundon (Waste) Ltd. The waste collection contract is currently with Grundon. Initial correspondence (the invitation to tender) is carried out exclusively via Health & Safety Services, but subsequent contacts are via the Radioactive Materials Purchasing and Stock Co-ordinator (RMPSC) in the School of AMS (extension 7043 or 7025) in consultation with the University Health & Safety Services (extension 8887). The URSO must be supplied with copies of all relevant documents (including a copy of the waste transfer note) following completion of the contract.

6.6 Disposal of radioactive gaseous waste Only small amounts of β and γ-emitters can be discharged at Whiteknights. Note that the annual limit for Tritium and Carbon-14 (250 MBq) is only 31 times the daily limit (8 MBq). For other β and γ-emitting isotopes, the daily disposal limit is 1MBq, with an annual limit of 50MBq. Conditions apply, including the requirement that the final outlet of the disposal route [discharge stack of fume cupboard] is at least 3 metres above roof height, and that the manner of discharge should prevent the re-entry of airborne radioactivity into any building.

 Fume cupboards Special authorisation is not required to carry out experiments in fume cupboards, where a small amount of incidental vapour may be discharged. The SRPS must be consulted before any work begins that may generate larger quantities of waste vapour or fumes.

Adequate fume cupboards of an appropriate design, venting to the atmosphere, must be installed when there might be a significant hazard from airborne radioactive material. Filters are not advisable as they need to be disposed of at frequent intervals. Cupboard flow rates (minimum 0.5 m.sec-1, ideally 0.75 m.sec-1 at 500 mm opening for work with radioactive materials) must be checked at termly intervals, or whenever there is doubt about the flow rate, and the results displayed in a conspicuous position on the front facia of the cupboard (whilst not obscuring vision). Cupboards fitted with the Everwatch monitoring system should be checked for correct flow rates before, during and after use, to confirm safe operation.

 Vapour hazards from volatile liquids Acquisition and disposal of radioactive materials

Care must be taken when storing volatile liquids with a significant level of radioactivity. A build- up of pressure must not be allowed to develop inside a closed vessel which will subsequently be opened. Any vapour should be allowed to vent to the atmosphere at a point remote from air intakes.

Note: Tritium contamination of refrigerated stores is a common hazard, due to isotopic exchange with hydrogen atoms in water. Refrigerators should be regularly checked for contamination, and regularly defrosted. Note that automatic defrosting [“frost-free” system] could lead to contamination of the laboratory air and/ or surfaces, since defrost water is often evaporated via the refrigerator expansion coils, and may be deposited anywhere within the lab, or within the ductwork of an air-handling system. Regular monitoring is essential, especially when volatile tritium compounds are being used.

6.7 Storage of radioactive wastes  Period of storage Solid waste of low activity ("bin/skip") should be disposed of as quickly as possible, and in any event, within 14 days. Aqueous liquid waste should be disposed of immediately up to the permitted limit, unless the half-life is 90 days or less (see below).

Both aqueous liquid and solid wastes containing radionuclides with a half life not exceeding 90 days may be stored for up to 900 days [30 months] to permit the activity to decay (Appendix 1). Organic liquid waste containing radionuclides with a half life not exceeding 90 days may be stored for up to 540 days [18 months] to permit the activity to decay (Appendix 1).

 Waste stores

All stores used for active wastes should be suitable for the wastes to be stored in them, and must contain a log-book to accurately record the contents of the store. The store must be kept locked, and the key should be available only to authorised persons (Section 2.8).

The Health & Safety Services radioactive materials storeroom (situated at the rear of the School of Physics adjacent to Health & Safety Services) is available for long-term storage of active waste being stored to allow decay of short-lived isotopes. All enquiries regarding use of this waste store must be addressed to the URSO (ext. 8887).

All waste deposited in a designated store must be properly contained (see below) and clearly labelled so as to identify:  The name of the originating person/ School  The USN of the waste  The estimated activity in the waste  The date of deposition, and  The projected date for removal. In addition, an entry should be made in the log-book which is kept within the store. Once the waste is removed for disposal, the log-book entry should be completed to show the actual date of removal.

 Storage containers: general All wastes must be kept in suitable containers which prevent any dispersion of the contents, whether or not the waste is VLL waste in temporary storage or higher activity waste that is in

decay storage. All containers (other than dustbins for very low-level solid waste - see Section 6.4) should be clearly labelled as above.

 Storage containers for liquids A suitable receptacle for storing active liquids is a metal drum with a plastic liner or an approved plastic container. Glass vessels are unsuitable because of risk of breakage: plain metal cans may leak through a faulty seam. Double containment techniques must be employed.

6.8 Summary of disposal procedures

1. Dispose of low activity solid waste and aqueous liquid waste up to the monthly limit as soon as reasonably practicable (and within 14 days of production for solid waste). Checks on activity may be necessary to demonstrate compliance with the VLL limits.

2. Remove radioactive signs and any identification marks before dustbin/skip disposal via VLL waste route

3. Do not store radioactive wastes for more than the specified period (Appendix 1).

4. Keep waste awaiting disposal in an adequate labelled container in a suitable locked radioactive materials store.

5. If in doubt contact the SRPS (see the SRPS Contact List) or the URSO (extension 8887)

7 OPEN SOURCE STOCK CONTROL The open source monthly accounting period is the calendar month. Requests for disposal information will be sent to SRPSs 7 days before the end of the accounting period and returns must be received within 7 days after the period. If this information has not been received by the requested date a reminder will be sent to the Head of School with a copy to the SRPS requesting a return within 4 days. If this correspondence is ignored the Head of School the SRPS will be given notice that work involving open sources must stop forthwith throughout the School. If a return is still not made by a stipulated date all open sources must be surrendered to the URSO. The Head of the offending School will have to submit a satisfactory written case to the next meeting of the University Health & Safety Committee (UHSC) if he wishes his School to be considered for resumption of work involving open sources. Note that the UHSC may at their discretion refuse to approve such a request until changes are made to procedures, or the School can demonstrate compliance with any conditions the Committee may impose.

This policy has been approved by the Vice-Chancellor and the University Health &Safety Committee.

It is strongly advised that Schools appoint an alternate or Deputy to act in the absence of the SRPS.

Users of open sources may obtain information regarding their USN's holdings of active material, etc from the Radioactive Materials Purchasing and Stock Co-ordinator (RMPSC) in the School of AMS (extension 7043 or 7025). Should disposals of any isotope inadvertently exceed the authorised limits in any month the URSO must be informed as soon as possible. Procedures will then require modifying to prevent the mistake being repeated. Acquisition and disposal of radioactive materials

Help and general advice on the use and disposal of open radioactive sources is available from the SRPS and URSO. If the URSO is to be approached the enquiry should be made through SRPSs, so that they remain fully aware of what is happening within the School for which they are responsible.

To avoid the unnecessary holding of radioactive materials, the Radioactive Materials Purchasing and Stock Co-ordinator (RMPSC) in the School of AMS (extension 7043 or 7025) will contact the holders of open sources from which disposals have not been made for 12 months, at the end of each year, to check that they are really required and are not being unnecessarily stockpiled.

8 TRANSPORT The packaging and labelling requirements associated with the transportation of radioactive wastes are complex. Transportation of radioactive waste off campus is normally effected only by authorised “persons”, who normally ensure compliance with the relevant Regulations as part of the contract for waste removal. Transport on public highways of radioactive substances in general is described in Safety Note 8. It is recommended that the advice of the URSO (extension 8887) is sought before intended transportation.

Note that these requirements do NOT apply to VLL waste, as this is technically regarded as “non-radioactive”.

9 REFERENCES The following references are available for perusal or loan from Health & Safety Services (extension 8888) or the University Radiation Safety Officer (extension 8887). 1. The Ionising Radiation Regulations 1999, HMSO, SI 1999/3232, ISBN 0-11-0856-14-7 2. Work with ionising radiation, HSC, Approved Code of Practice, HMSO 1999, ISBN 0- 7176-1746-7 3. The Radioactive Substances Act 1993, HMSO, ISBN 0-11-541293-7 4. The Radioactive Substances (Phosphatic Substances, Rare Earths etc) Exemption Order SI 2710/1962, HMSO 5. The Radioactive Substances (Uranium and Thorium) Exemption Order SI 2711/1962, HMSO 6. The Radioactive Substances (Prepared Uranium and Thorium Compounds) Exemption Order SI 2711/1962 HMSO 7. The Radioactive Substances (Geological Specimens) Exemption Order SI 2712/1962, HMSO 8. The Radioactive Substances (Waste Closed Sources) Exemption Order SI 1831/1963, HMSO 9. The Radioactive Substances (Electronic Valves) Exemption Order SI 1797/1967, HMSO 10. The Radioactive Substances (Smoke Detectors) Exemption Order SI 953/1980, HMSO 11. The Radioactive Substances (Gaseous Tritium Light Devices) Exemption Order SI 1047/1985, HMSO 12. The Radioactive Substances (Luminous Articles) Exemption Order SI 1048/1985, HMSO 13. The Radioactive Substances (Testing Instruments) Exemption Order SI 1049/1985, HMSO

14. The Commission Regulation (EURATOM) 3227/76 19 October 1976, The European Communities

10 ACRONYMS AMS (School of) Animal and Microbial Sciences DEFRA Department of the Environment, Food and Rural Affairs SRPS School Radiation Protection Supervisor EA Environment Agency

EURATOM European Atomic Energy Community HMSO Her Majesty's Stationery Office IRR Ionising Radiations Regulations ISBN International Standard Book Number RMPSC Radioactive Materials Purchasing and Stock Co-ordinator RPA Radiation Protection Adviser RSA Radioactive Substances Act URSO University Radiation Safety Officer USN University Source Number The University of Reading Safety Information Sheet

UNIVERSITY OPEN SOURCE STOCK AND DISPOSAL LIMITS SG18 APPENDIX 1

The various authorisations for the University are summarised below; readers should refer to the original Certificates held by the University Radiation Safety Officer (URSO)(extension 8887), and displayed in user departments, for precise information.

1 MAXIMUM OPEN SOURCE STOCK PERMITTED AT WHITEKNIGHTS  CARBON-14 1 GBq (27 mCi)  IODINE-125 1 GBq (27 mCi)  PHOSPHORUS-32 600 MBq (16 mCi)  SULPHUR-35 500 MBq (13.5 mCi)  TRITIUM-3 5 GBq (135 mCi) {Note that this amount is a reduction in the 40 GBq previously permitted)  OTHER , 300 MBq (8 mCi)  Any alpha-emitting radionuclides 5 MBq (in total)

2 SCHOOL OPEN SOURCE ALLOCATIONS A formal allocation is no longer made as more than 90% of materials are purchased within the School of AMS. Should any difficulties arise the URSO will be the final arbiter.

3 MAXIMUM DISPOSALS PER MONTH 3.1 Solid waste (BIN/SKIP) – Very Low Level Waste ONLY – to London Road skips  Alpha emitters must not be disposed of via this route. [There is currently no authorised route for the disposal of alpha emitters, unless use can be made of one of the Exemption Orders.]  Limits depend on the size of the skip and the frequency of emptying.  Not more than 40 kBq (1.1 Ci) per item. (except CARBON-14 and TRITIUM-3, where the limit is 400 kBq in total.)  Not more than 400 kBq (11 Ci) per 0.1 m3. (except CARBON-14 and TRITIUM-3, where the limit is 4 MBq (0.11 MCi) in total.  Must be disposed of within 14 days of production. Note: The volume of a domestic dustbin is ~ 0.1 m3. A typical skip has a volume of 5 m3 and is emptied weekly - in such a case the monthly disposal limit is 80 MBq (2.2 mCi) per skip for “other” isotopes. The waste must not be identifiable as “radioactive”, and the individual limits must also be observed. Thus, for example, it would be permitted to dispose of up to 20 MBq of 35S, 150 MBq of 3H and 50 MBq of 14C in a 5m3 skip that was emptied weekly, provided that the “single item” limits were also observed.

3.2 Aqueous waste (SINK)  TRITIUM-3 + CARBON-14 500 MBq (13.5 mCi)  OTHER , 200 MBq (5.4 mCi)

______April 05 SG18 Appendix 1(1) University open source stock and disposal limits ______

3.3 Organic scintillant (DRUM) Removable by Shanks  TRITIUM-3 + CARBON-14 200 MBq (5.4 mCi)  OTHER , 40 MBq (1.08 mCi)

Removable by Grundons.  TRITIUM-3 + CARBON-14 200 MBq (5.4 mCi)  SULPHUR-35 40 MBq (1.08 mCi)  Note that Grundons would not be able to remove liquid scintillant containing isotopes such as Phosphorus -33 – this falls within the “other ,” classification, and would have to be removed by Shanks. Users of liquid scintillation fluids should inform the URSO and the RMPSC if they are likely to use any isotope other than 3H, 14C or 35S before commencing such work, since this would require the use of Shanks as the waste disposal contractor.

3.4 Gaseous waste (ATMOSPHERE)  TRITIUM-3 + CARBON-14 8 MBq per day (220 Ci per day) but not more than 250 MBq per year (6.5 mCi per year)

 Any other radionuclide (except  emitters) 1 MBq per day (27.5 Ci per day) but not more than 50 MBq per year (1.3 mCi per year)

3.5 Other solid waste Currently, the University does not have any other authorised routes for disposal of “other solid waste”. The former ability to send waste for incineration at Compton no longer applies.

4 STORAGE FOR DECAY OR COLLECTION The wastes described below can be stored up to the maximum periods indicated below in either the purpose built store belonging to Health & Safety Services at Whiteknights, or the equivalent store at AMS. Note that “Collection” only applies to organic liquid waste.

4.1 Aqueous waste: up to 900 days (30 months). Maximum activity 620 MBq (17 mCi). Applies only to  and  emitters with a half-life of less than 3 months. (Volume not to exceed 0.1 m3)

4.2 Organic scintillant – up to 540 days (18 months)  TRITIUM-3 and CARBON-14 200 MBq (5.4 mCi)  OTHERS – ANY / 40 MBq (1.08 mCi) (volume not to exceed 1.0 m3)

4.3 Solid waste: up to 900 days (30 months). Maximum activity 520 MBq (14 mCi). Applies only to  and  emitters with a half-life of less than 3 months. (Volume not to exceed 6 m3) Such waste MUST be disposed of via the VLL route after decay has taken place

______SG18 Appendix 1(2) April 05 University open source stock and disposal limits ______

5 USE AND DISPOSAL at other University premises Open radioactive sources must not be used, accumulated or disposed of at any University premises other than Whiteknights, with the exception of VLL waste at the London Road site. Licences previously issued for use/ storage at University farms and the London Road site have all been cancelled.

Note: Any University site, including Bulmershe Court is permitted to use a limited number of low activity closed sources for teaching purposes only (i.e., when acting as an educational establishment) without the need for registration under the Radioactive Substances Act, provided that the sources all comply with the relevant Exemption Order.

At the time of writing, all such closed sources had been disposed of, and no radioactive sources remain. Any proposals to acquire new closed sources must be thoroughly discussed with the URSO before being effected, and funds must be available to pay for the final disposal of the sources when no longer required. See Safety Guide 16 [“Working with Ionising Radiations”] – Section 8.2, “Closed Sources.”