Decontamination And Volume Reduction Techniques For Nuclear Decommissioning

1. Decontamination And Volume Reduction Techniques For Nuclear Decommissioning Innovation in Nuclear Decommissioning: New Technologies and Research, SAFESPUR Forum, July 9, 2008 G.R. Elder Bradtec Decon Technologies Ltd

2. Agenda • Bradtec • Getting from the bright idea to full implementation • Innovative techniques for chemical decontamination: - EPRI DFD - EPRI DFDX • Examining the relationship between decontamination and metal recycling • Conclusions NB Other areas of Bradtec’s operation include graphite management and Magnox fuel element debris management, not included in this talk

3. Bradtec • Formerly CEGB radwaste R&D team • Specialist in developing nuclear decommissioning technology • Management owned UK company • Connection with UWE • In business for 18 years • Mainly overseas clients Quad Cities RWCU Heat Exchanger Tube Bundle , post EPRI DFD Treatment Stainless Steel Surface following EPRI DFDX process

4. Getting from Idea to Full Scale • Bradtec’s speciality • Needs a combination of skills and attributes: • Science & Technology • Business • Long term commitment (can be 10-20 years from idea to maturity) • Researchers need to get involved in real world applications • Only way to make the connection between the problem and the solution

5. Chemical DecontaminationEPRI DFD and DFDX

6. Chemical Decontamination Chemical decontamination is used routinely at operating plants to reduce radiation exposures More powerful processes were needed for retired plants and components less concern about corrosion more effective, less residual contamination

7. EPRI DFD Process DFD - Decontamination for Decommissioning Dilute recirculating chemical decontamination process – no liquid waste Uses the established techniques of operational chemical decontamination processes Decontamination of primary systems at US nuclear plants in late 1990’s, resulted in major dose savings

8. Process Chemistry • Dissolution by Fluoroboric Acid • Fe2O3 + 6 HBF4 - - > 2 Fe(BF4)3 + 3 H2O • Capture by Ion Exchange (R = IX Resin site) • 2 Fe(BF4)3 + 6 H+ - R - - > 6 HBF4 + 2 Fe 3+ - R3 • Removal of Chemical (at end) • HBF4 + R - OH- - - > R - BF4- + H2O

9. EPRI DFD Outline Controlled dissolution of oxide layers, micron by micron removal Removal of some base metal to achieve recycling levels Deposited oxide Indigenous oxide Base metal Spent Acid And Metals Refreshed Acid Treatment Skid Remove metals ions by absorption (IX) or plating (DFDX) Replace metals with protons (H+), regenerates acid Pump Mass transfer of metals and radioactive species from contaminated surfaces to a collection medium

10. Principle of Operation • Mobile equipment supplied by contractor (and taken away afterwards) • Water supplied by the site • Chemicals and radioactivity end up in the secondary waste • Clean water returned to the site • Secondary waste (resins or metal powder) stays with the site for disposal

12. EPRI DFDX Uses EPRI DFD process chemistry Replaces cation exchange column with in-line electrochemical ion exchange unit EPRI DFDX produces large particle metal powder waste small volume no organic material produced metal powder waste or porous carbon electrode cementation or dewatering of waste Chemicals returned to system for use in further decontamination

13. ENS DFDX Equipment

14. Decontamination and Metal Recycling

15. What can be recycled? • Decontamination is a useful precursor to recycling • A surprisingly large proportion of all radioactive wastes can be recycled • Lead and other non-ferrous metals • Steel (carbon and stainless) • Concrete • Graphite • Uranium/plutonium • Not neutron activated materials (in general)

16. How can you recycle? • No different from conventional recycling • Separate the useful constituents from the waste by processing • Manufacture new products from those separated constituents • Strong preference to recycle into new nuclear industry products, rather than releasing for unrestricted public use • Not so much a technical issue, more a stakeholder concern • Some examples follow

17. Recycling Lead • About 100,000 tonnes contaminated lead in UK • Can be used as shielding for transport, storage or disposal containers • Recycling performed by melting the contaminated lead and filling the inter-gap in a double-skinned steel container • Radioactive melting dross disposed of as secondary waste

18. Recycled Lead Products

19. Decontaminated Steel – (Part of a BWR Heat Exchanger)

20. Recycling the clean steel • Can be done by rigorous and careful monitoring, and then release for conventional treatment as steel scrap • Already being done • Preference in future to make nuclear industry products such as: • Simple high-volume products - reinforcing bar etc • Waste containers (HHISO’s, NIREX drums etc)

21. Conclusions • Decontamination and recycle/reuse could make a large impact on the UK decommissioning challenge • Decontamination reduces radiation and contamination in dismantling • Decontamination is often the key to recycling/reuse • Recycling and reuse could significantly reduce overall volumes of ILW and LLW • Key to achieving accelerated decommissioning