Consignment of Waste to the Disposal of Hazardous Waste Service

Transcription

1 Radioactive Waste LR 31 Who should read this document This document should be read by the Head of Department, Departmental Radiation Protection Supervisors, users of radioactive materials and their supervisors. Background to the Control of Radioactive Waste The disposal of radioactive waste is heavily regulated by law and is a matter of great public concern, resulting in apparently cumbersome and time-consuming record keeping. The standards that apply to the disposal of radioactive waste increase frequently, and failure to comply with current UCL procedures not only exposes UCL to the risk of prosecution, but may also result in the withdrawal of the Permits issued under the Environmental Permitting Regulations 2010 (EPR10) i.e. preventing any work with radioactive substances by any department on the sites concerned. UCL is committed to using Best Available Technique for the use and disposal of radioactive materials, details can be obtained from the Radioactive Waste Advisor, Paul Monk. Detailed overleaf are a number of methods that may legally be used for the disposal of radioactive waste, however not all methods may apply to every UCL site. Each Departmental Radiation Protection Supervisor is issued with details of the disposal routes that apply to their department and the maximum amount of radiochemical that may disposed of via that route. It is the duty of the RPS to inform you of the limits that apply to your experiments you should not perform any work with radiochemical until you have obtained the limits from your RPS. Concern is often expressed over the environmental impact of the disposal process. All disposals are very strictly regulated by Permits under EPR10 and these are only granted after careful assessment of the impacts to health, safety and the environment. Means by which you can ensure that the environmental impact of your work is kept to a minimum are: only use radioactive materials if there is no safer alternative - and only order and use the minimum; see also LR - Risk Assessment comply with allocations given to you by your RPS, see also LR - Acquiring Radioactive Materials. practice with dummy runs choose techniques which minimise the amount of waste generated. Consignment of Waste to the Disposal of Hazardous Waste Service All waste to be disposed of by the UCL Disposal of Hazardous Waste Service (DHWS) must be consigned to the Service by prior appointment. This means that you make an appointment with the DHWS and hand the waste over to a member of the Service. You must sign a consignment note as part of that process. You must not leave any waste outside any of the waste stores. You must ensure that the exterior surfaces of all containers consigned to the DHWS have been monitored for contamination and decontaminated to below 0.4 Bq/sq cm. When you sign the consignment note you will also be signing a declaration to this effect.

2 Waste Disposal Routes Aqueous Waste Aqueous waste must only be discharged directly down an authorised disposal sink. The waste should be carefully poured down the sink, avoid any splashing, and flushed away with copious quantities of water. The discharge of aqueous waste is carefully regulated by EPR10 and the risks to health, safety and the environment are controlled by the massive dilution of the waste. To dispose of aqueous waste you must: Ensure your proposed disposal will not cause a breach of the departmental aqueous disposal allocation. You may only perform the experiment if you have sufficient allocation for the disposal of all of the waste prior to doing the experiment. Flush the waste away with a large volume of water; avoid any splashes by the disposal process. Ensure no organic solvent waste is poured down the sink. Record the disposal (isotope, activity in MBq, the date) in a disposal log by the sink. You must not: Store aqueous waste for decay purposes, UCL is not authorised to do this. Pour aqueous waste onto absorbing media, e.g. vermiculite, cat litter etc., in order to transform it into solid waste, (the disposal of which, incidentally, is likely to have a greater cost and environmental impact than the corresponding aqueous disposal). Dispose of scintillation cocktail down the sink, even if it is eco-friendly or biodegradable. Gaseous Waste To dispose of gaseous waste you must comply with the following: The disposal of gaseous radioactive waste is only authorised on one UCL site, therefore you must ensure, from your RPS or the UCL RPO that you have authorisation before performing an experiment that releases radioactive gas. If you have a gaseous release Authorisation, you must ensure that you comply with all of the limits imposed, e.g. a daily and an annual limit. The area where the radioactive gas is released, typically an authorised fume cupboard, must have a disposal log and you must complete this each time you cause a release (with isotope, activity in MBq, the date and your name). NB If your experiments release any gaseous products, ensure that there is no mechanism by which those products could lead to contamination (e.g. expiration of 14-Carbon). Organic Liquid Waste Organic liquid waste may arise from scintillation counting or from experiments that combine radiochemicals with organic solvents. Scintillant procedure 1. Scintillation waste must be accumulated in black medibins. The correct medibins are available from Facilities Services (FS), however it is intended that these containers should be made available through the UCL iprocurement system and that when this is the case the FS will cease to supply them. 2. It is no longer necessary to segregate scintillant waste by radionuclide (indeed it is now unhelpful to do so). 3. You must ensure that three criteria are met in order to dispose of your bins: 4. The surface contamination on the outside surfaces of each bin must be below 0.4Bq/sqm when monitored over 300 sq cm.

3 5. The surface doserate measured on the outside surfaces of each bin must be below 5 Sv.hr The activity in each drum must not exceed 10 MBq without prior agreement from the 7. Procedures must be in place to ensure that each medibin contains no more than 7 litres of scintillant cocktail or any other organic solvent. 8. For each disposal into the medibin, the radionuclide, activity, reference date for that activity, scintillant cocktail and contents of the vials must be recorded (this latter information is used by the disposal companies). 9. Don t undo vial flip-tops - this may create aerosols. Just dispose of the entire vial. 10. Solid scintillant products containing no liquid should go into the solid waste stream. 11. Dispose of the medibin within three months of starting to use it even if the bin is not full. 12. When you are ready to dispose of the medibin, contact the DHWS to make an appointment to consign the waste to them. Organic liquid waste procedure 1. Organic liquids contaminated with radiochemical should be decanted into UN approved plastic drums. The DHWS will be able to offer advice on the suitability of particular drums and whilst they may currently be able to provide suitable drums, it is intended that these should be made available through the UCL iprocurement system and that when this is the case the DHWS will cease to supply them. 2. There is no requirement to segregate by radionuclide. 3. You must ensure that three criteria are met in order to dispose of your bins: 4. The surface contamination on the outside surfaces of each bin must be below 0.4 Bq/sq cm when monitored over 300 sq cm. 5. The surface doserate measured on the outside surfaces of each bin must be below 5 Sv.hr The activity on each drum must not exceed 10 MBq without prior agreement from the 7. Record radionuclide(s) and activities, type and volume of solvent. 8. When the container is full, or after three months of starting to use it, contact the DHWS to arrange for its disposal. Solid Waste General General solid radioactive waste comprises gloves, tissues, solid experimental residues etc. Radioactive sharps and animal carcasses have different procedures (see below). To dispose of general solid radioactive waste you must: 13. Solid waste must be accumulated in red medibins. The correct medibins are available from the DHWS, however it is intended that these containers should be made available through the UCL iprocurement system and that when this is the case the DHWS will cease to supply them. 14. It is no longer necessary to segregate solid waste by radionuclide (indeed it is now unhelpful to do so). 15. You must ensure that three criteria are met in order to dispose of your bins: a) The surface contamination on the outside surfaces of each bin must be below 0.4Bq/sq cm when monitored over 300 sq cm. b) The surface doserate measured on the outside surfaces of each bin must be below 5 Sv.hr -1.

4 c) The activity in each drum must not exceed 10 MBq without prior agreement from the 16. Instructions for the use of the drums are available from the 17. Record the radionuclide(s) and activities. You must ensure that the activity of the waste is properly decay-corrected as appropriate to the radionuclide. See also LR - Record Keeping and Estimation Techniques. 18. When the bin is full, or after three months (whichever is the sooner), it should be delivered by a member of the department, by prior appointment, to the DHWS at the designated store for the site. An empty bin is issued in return for the full one by DHWS however it is intended that these containers should be made available through the UCL iprocurement system and that when this is the case the DHWS will cease to supply them. A record must accompany each bin detailing the radionuclides and their total activities on the date of disposal. The record should be signed by the RPS or the person responsible for generating the waste. 19. You must not put liquids into the solid waste stream. Sharps Sharps contaminated with radioactive material must be put into an appropriate sharps bin. When the bin is full, or after three months from starting to use the bin, contact the DHWS to arrange for disposal. You must record the radionuclide(s) and their total activities on the date of disposal. Carcasses All radioactive carcasses should be wrapped and labelled, (radionuclide, activity, Department, phone no., contact name) and deposited in a freezer. Contact the DHWS to inform them of the waste and the service will arrange for collection by specialist contractor. Sealed Sources The disposal of a sealed source, including high activity sealed sources (HASS), requires special arrangements and is subject to an individual contract with a specialist disposal contractor. Those wishing to dispose of a sealed source should contact FS. Very Low Level Waste ( Dustbin Waste ) UCL does not operate the system whereby radioactive waste of low activity may be disposed of through the normal laboratory waste system (i.e. as non-radioactive waste). All radioactive waste must be disposed of as either solid radioactive waste, radioactive scintillant waste, radioactive aqueous waste or radioactive gaseous waste and recorded as appropriate. Lab equipment and furniture The RPS or Local Manager must ensure that when refurbishment or decommissioning of radiation facilities takes place all areas, laboratory furniture and equipment must be monitored for radio-contamination, fully decontaminated where necessary and all trefoil warning signs removed from any items before disposal. A certificate of decontamination should be completed by the department and given to the Disposal Agent, or UCL Facilities Services as appropriate, see overleaf. Where items cannot be decontaminated, disposal should be arranged through FS. Lead Pots and Packaging See You must check lead pots and packaging for contamination prior to disposal. Provided that the packaging is free from radioactive contamination: 2. The cardboard box and metallic outer container (tin) must be recycled. You must obliterate all radiation warning markings before recycling the boxes by putting them into a bin lined with a clear bag.

5 3. Polystyrene and foam packaging inserts are not recyclable and so must be disposed of as non-recyclable office wastes by putting them into a bin lined with a black bag. 4. Plastic packaging may also be recycled (by placing into a bin lined with a clear bin liner) provided that any lead shielding has been removed and that all radiation warning markings are obliterated. 5. To dispose of lead pots/inserts: a) Contact FS and obtain a 10 litre metal pail. b) Put the lead pots into the pail and when it is half-full, contact FS to arrange collection. You will need to complete and sign a Lead Pot Contamination Certificate to declare that you have verified that the lead pots are free from contamination. If you are unfortunate enough to discover that a package is contaminated contact FS for advice. Techniques for Estimating Radioactive Waste See also LR - Record Keeping and Estimation Techniques. It is essential that the radionuclide activity is established prior to disposal; you must ensure that no disposal takes place without having established that you have an allocation for the disposal. To assist the estimation process try to break the experiment down into standard procedures (e.g. pipetting etc.) and estimate the waste from that procedure. Your estimates should be as precise as possible but certainly within 10%, this can be verified by liquid scintillation counting of samples of aqueous waste. The consequence of underestimating the activity levels for any waste stream is that this may exceed your departmental allocations for that waste stream which could lead to prosecution of UCL for breaches of the Radioactive Substances Act. Overestimation of the activity levels for any waste stream may indicate to the Environment Agency that there is no proper control of the use of radioactive materials, and hence invite enforcement action - you need also to remember that disposal costs for solid and liquid organic waste are high - about 30 per MBq. Records for Radioactive Waste Records of radioactive waste must be kept by the department for at least 2 years after disposal. A suitable record will include the following information: radionuclide activity in MBq date route of disposal Safety Services Reference(s): LR31 First Published January 1999 Reviewed November 2017