An History of Mobile Solidification in the UK

1. An History of Mobile Solidification in the UK Presented by Michael Grave Mitsui Babcock Energy Ltd And co-author Arthur Willis British Nuclear Group for RWIN Meeting 19th July 2005

3. Historical Context Michael Grave Decommissioning Contactor 1982 to 2005 NEI Waste Technologies Ltd NEI International Research & Development Rolls-Royce Mitsui Babcock Energy Ltd Mobile Solidification Service operated out of Gateshead office. Arthur Willis Mostly owner operator Contractor since 01/04/05 1973 to 2005 CEGB Nuclear Electric BNFL Magnox British Nuclear Group Magnox and AGR

4. Background White Paper on Radioactive Waste Management July 1982 Created NIREX Push for Repository Design (LLW and long lived ILW) Need to consider upfront processes Conditioning processes Packaging NEI Waste Technologies 1982 To operate a repository and lead in services

5. Technology Transfer USA experience promising NEI Waste Technologies sought to influence CEGB Initiated technology transfer from US shareholder CEGB reviewed worldwide experience including German MOWA plant French PEC plant NEI Waste Technologies Ltd (Chem Nuclear Systems) plant CEGB Organisation involved Barnwood Berkeley Laboratories NE Region Lab at Wythenshaw near Manchester

6. Development of Processes Study of solidification science and technology UKAEA Winfrith Work subsequently played an important part in the process selection for the BNFL Sellafield Cement Solidification Plant UKAEA Windscale UKAEA Dounreay NEI Waste Technologies did some work for them on solidifying TBPOK, a solvent used in reprocessing BNFL Initially sought ideas widely for evaluation, which included NEI Waste Technologies

7. Fixed Solidification Plants A number of fixed plants have been built in UK e.g. Using Cement Trawsfynydd Hinkley Point A Dounreay Sizewell B Sellafield Winfrith Two types of cement PFA and BFS Using thermosetting polymer Trawsfynydd

8. Solidification Civil Nuclear Plant Some fixed plant from late 1970s Trawsfynydd and Hinkley A Fuel corrosion product sludges For Sea dumping with wastes from other sites Trawsfynydd plant built 1980 to 1983 Sea dump was abandoned Plant using thermosetting polymer Actively commissioned in 1985 First active campaign 65m3 in 500 shielded drums Mothballed re-commissioned after station closure 1993 3 further campaigns > 1500 drums of IX resin

12. World Activities - Processes Important to learn from others Solidification among others in: - W Europe USSR and satellites USA Japan Media used Urea Formaldehyde (abandoned in USA) Bitumen Resins as at Trawsfynydd and a mobile plant of EdF Cement Also synthetic rocks and glasses but mainly for HLW Many other panaceas including Sodium Silicate

13. USA process Partner of NEI Waste Technologies Cement with various additives to meet standards PWR and BWR wastes Lubricating Oil Boric Acid Filter Aids IX Resins etc Standard for Solidification 10CFR61 requirements: - Compressive strength Fire, Water and Biological tests Leach rate etc

14. World Activities - Plant Diverse approaches Twin screw mixers – pre mixed cement and waste outside waste drum Fixed plant – often drum moves from station to station Filling Mixing Curing Lidding Quality check etc Similar approaches in mobile plant ISO containers Bolt to floor in which case “modular”

15. USA - Large container solidification Container is key plant item All operations are taken to the container Standard one-size fits all fill-head placed on top of container 2000 litre to 9000 litre size of container (or liner) Liner fits in side range of transport flasks References in the paper to the advantages of larger containers Fill head can also be used on 200 litre drum Basis of Mitsui Babcock 200 litre drum – LLW plant

16. Some issues with large containers Disposable throw away process plant can be built into the container Paddle De-watering equipment Level monitoring processes (plant had 3 independent ways) Other processes linked to fill-head Paddle drive connection Remote CCTV Waste in and water out feed lines Less handling/transport/dose for unit waste quantity Weight and size impacts on transport/repository

17. Initial Developments: Magnox/AGR Review of 3 systems for use in UK The USA large liner system selected for further trials A constraint was the limited number of transport containers adopted by NIREX in UK Limited maximum size of liner to 2600 litres Two development issues undertaken by NEI Waste Technologies Demonstration of concept of a mobile service Demonstration on relevant waste streams

18. Oldbury Demonstration 200 litre demonstration plant Gas circulator oil Trials on oil in laboratory Demonstrate suitability of formulation Produce a tolerance box within which formulation was considered successful 6 drums solidified Plant delivered from and returned to Gateshead in a week Operated by contractor

19. Development of Formulations Undertaken by David Saul of NEI Waste Technologies No quality standard like 10CFR61 in UK Set of tests agreed with client Compressive strength Impact tests Water immersion An initial formulation developed for all ILW streams Magnox and AGR Pond Sludges IX resins (granular and bead) Filter Aids Silica gel

20. A typical USA large liner plant

21. Large Container Mixing Trials Successes Concept of solidifying in large containers Waste quality process control was simple to understand Paddle design and operating procedures well understood Fill head design and plant and control systems simple and had redundancy Full scale demonstrations on Silica gel Varivoid filter sand Magnesium Hydroxide Sludge Diatomaceous earth filter precoat Bead Ion Exchange Resin

22. Large Container Mixing Trials Difficulties Filter sand could not be suspended (process amended) Magnesium Hydroxide Sludge expected to and did block filters (settling alternative but was very slow) Multi-level redundant systems effective but too simple for UK tastes at the time Combination of management and engineering controls also outside UK experience for nuclear plant Some of the quality data of the mix was obtained by scientific deduction rather than direct measurement

23. Continuing developments and services The British Nuclear Group solidification development facility was set up at Chorley following a competitive tendering exercise after 1987 Mitsui Babcock (then NEI) undertook the first full LLW mobile solidification and waste disposal service on IX resins up to 12GBq/te activity in 1990 Learning curve for Drigg as well as the contractor Other contracts followed for diverse wastes such as IX resins Incinerator Ash Drain sludges etc

24. British Nuclear Group LLW Plant First mobile plant in 1990 for LLW sludges Hartlepool PS produced 500No. 200-litre drums Simple in drum mixing with lost paddle A number of manual operations included meant the activity levels were limited by need to control operator dose Continued use of the plant around various sites Magnox AGR Defence etc

26. British Nuclear Group Systems (2) Plant developed for ILW IX Resins Sludges Transportable Intermediate Level Waste Solidification Plant (TILWSP) Commissioned in 2003 at Trawsfynydd Uses 2600 litre drum (NIREX standard 3m3) Process plant in ISO containers Walls used for containment and shielding Fully remote operation using a sequenced controller Remote quality checking for hardness and free water

30. British Nuclear Group Systems (3) Plant Developed for Dewatering of Sludges Transportable Sludge Dewatering Unit (TRSDU) Fully mobile plant in ISO container (30 ft) Can be used as a pre-stage to TILWSP Has some benefits of final waste product volume by removing excess water in advance of solidification Is used to give control of water/cement ratios Shortly to be installed at Trawsfynydd PS Dewater large volumes of tank wash water

31. TILWSP and TRSDU goals To be used for ILW sludges ILW IX resins On the power station sites Magnox AGR To be transportable between sites Use IP2 transport packages to contain contaminated materials Confidence based on 15 years mobile experience with LLW plant

32. Mitsui Babcock Mobile Service Has operated since 1986 Nearly 20 years experience with 4 solidification plant and a grouting plant Has been described in poster paper at first RWIN conference and also BNES Cumbria seminar. Service has included in part or full Selection of formulation (library of Process Control Programmes) Plant configuration (variable) Obtaining of regulatory and disposal authorisations Transport and disposal to Drigg (road, rail and sea) Gateshead base with supporting active laboratory

33. Mitsui Babcock Plant version 2

34. Key Plant Features Variable configuration of plant Advantages Different waste forms Different activity levels Different site access conditions (often very difficult) Minimise capital investment in plant Keep as simple as possible Choice of fully manual or semi-remote operation Pump internal can be thrown away if necessary Fill head is very small and easily transported These are the only two contaminated items

35. Mitsui Babcock Plant version 3

36. Mitsui Babcock Grouting Plant

37. Future Developments Mitsui Babcock Energy Ltd inherited the business of Rolls-Royce Nuclear Engineering Services in 2002 Internally funded development from 2003 Up grade plant to modern standards Incorporate lessons learned by operating team from solidifying over a thousand drums of waste - nearly 10 different waste types Improve waste loading efficiency as delivered to Drigg Adapt to handle some ILW types Focus on fit for purpose design low capital cost, simple operation Waste Disposal Authority needs Focus on service and not plant

38. The Future Advent of NDA leading to contractor services Wide range of operational waste backlogs remain Additional decommissioning wastes arising One size will not fit all and flexibility in waste processing needs will be required Highly complex nuclear solutions are not the answer for lower activity wastes NDA will look for value for money Mobile plants avoid the need for capital investment including new buildings British Nuclear Group and Mitsui Babcock Energy Ltd have responded with mobile plant developments

39. Not a conclusion - A Post Script!

40. Acknowledgements