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Study on recycling of fusion activated materials: Identify activation levels and decay time requirements of irradiated material (deliverable 3) R. Pampin.

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Presentation on theme: "Study on recycling of fusion activated materials: Identify activation levels and decay time requirements of irradiated material (deliverable 3) R. Pampin."— Presentation transcript:

1 Study on recycling of fusion activated materials: Identify activation levels and decay time requirements of irradiated material (deliverable 3) R. Pampin EURATOM/UKAEA Fusion Association TW5-TSW-001&002 final meeting Culham Science Centre, October 2006

2 TW5-TSW-001 final meeting, Culham Science Centre, October 2006 2/17Background European Fusion Programme strategy for fusion irradiated waste:  Release from regulatory control mildly activated material, usually lifetime, bulky, outer components: TFC, VV, LTS.  Recycle within the nuclear industry (fission/fusion) the rest. PPCS radioactive waste results: all material cleared/recycled within 100 years, but:  Release criteria: out-of-date IAEA clearance levels (1996).  Lack of detail in the models (e.g. outer components).  Inadequate modelling of particular materials (e.g. LiPb).  Recycling criteria based on radiological parameters only, which were imprecise and over-conservative.

3 TW5-TSW-001 final meeting, Culham Science Centre, October 2006 3/17Background IAEA 1996/2004 clearance levels: many changes affect fusion- relevant radionuclides (e.g. 30-fold decrease in Ni-63 level). TW5-TSW-002 D1 report on implications, TW5-TSW-001 D3 report on specific effects on PPCS-AB.

4 TW5-TSW-001 final meeting, Culham Science Centre, October 2006 4/17Background PPCS recycling criteria: some sensible for certain waste streams following certain routes (e.g. re-melting of steels); “complex recycling” limit is: (a) noticeably over-conservative and (b) uncertain: depends on route followed ! waste categorisation criteriacontact dose (mSv/h) decay heat (W/m 3 ) CI Permanent disposal (PDW)> 20> 10 Complex recycling (CRM)2 – 201 – 10 Simple recycling (SRM): remote hands-on < 2 < 10 -2 < 1 Clearance< 1

5 TW5-TSW-001 final meeting, Culham Science Centre, October 2006 5/17 Scope and objectives To review and update PPCS work using:  Up-to-date international clearance levels: IAEA 2004.  Up-to-date nuclear data: EAF 2005.  Practical feasibility criteria: findings of this task.  More accurate modelling methodology (e.g. LiPb flow) and increased level of detail (e.g. TFC and breeder materials). With the aim of:  Determining more realistic amounts and activation features of the material inventory.  Identifying interim decay times required during recycling.  Identifying potential for (a) reduction of waste, and (b) simplification of processes.

6 TW5-TSW-001 final meeting, Culham Science Centre, October 2006 6/17 Material inventory PPCS-AB based on the HCLL blanket concept, PPCS-B based on the HCPB blanket concept.

7 TW5-TSW-001 final meeting, Culham Science Centre, October 2006 7/17 Industry experience Distinction between recycling and refurbishment:  Refurbishment: little or no processing, on-site, immediate or early reuse in the fusion plant (e.g. LiPb, ceramics).  Recycling: greater processing, off-site, later reuse in the nuclear industry in general. Recycling strategies in the industry exist for:  Very low activity: fabrication of simple components.  Very high activity: de-activation and re-fabrication of internals. Recycling routes envisaged for all PPCS-AB and PPCS-B materials (TW5-TSW-001 B report).

8 TW5-TSW-001 final meeting, Culham Science Centre, October 2006 8/17 Radiological levels Use radiological levels to ascertain storage times needed for the activity to decay to levels facilitating recycling processes:  Clearance: C.I.  Lower RH needs: contact dose rate.  Lower cooling needs: decay heat rate.  Easier transport: ?

9 TW5-TSW-001 final meeting, Culham Science Centre, October 2006 9/17 Computational tools and models

10 TW5-TSW-001 final meeting, Culham Science Centre, October 2006 10/17 Results: clearance New IAEA levels  increased amounts of material to be recycled: OB VV and IB TFC. Time scales: few years OB, few decades IB. Segregation alleviates this.

11 TW5-TSW-001 final meeting, Culham Science Centre, October 2006 11/17 Results: refurbishment Refurbishment of LiPb is possible and reduces considerably the amount of operational waste (from 124000 to 97000 tonnes). PPCS-B ceramic breeder and other materials also possible, but much lower impact  strategic value?

12 TW5-TSW-001 final meeting, Culham Science Centre, October 2006 12/17 Results: recycling PPCS-AB results:  Ex-vessel: most materials, individually or as TFC, VV and LTS, show contact dose rates < 2 mSv/h (earlier OB than IB).  Ex-vessel: many of these show < 0.01 mSv/h after suitable decay time (few years OB, several decades IB).  In-vessel: poloidal variation is negligible.  In-vessel: all Eurofer and LTS neutron shield (WC) show contact dose rates < 2 mSv/h after ~75 years.  In-vessel: LiPb breeder and W armour still exceed 2 mSv/h after 100 years: Dominant nuclides arise from Pb and W isotopes, hence impurity control not very useful in this case!  isotopic separation needed.

13 TW5-TSW-001 final meeting, Culham Science Centre, October 2006 13/17 Results: recycling - impurities W and LiPb  PPCS specifications contain many impurities: (a) manufacturer limits, (b) detection limits. Co, Ni, Nb, Mo, Eu, Sm, Gd, Tb, Pt, Ir, Pb, U, Th, Bi, Ag, Cd, Ba, Tl, Co, Nb

14 TW5-TSW-001 final meeting, Culham Science Centre, October 2006 14/17 Results: recycling - impurities PPCS-B results:  In-vessel: again, (nearly) all Eurofer and LTS neutron shield (ZrH) show < 2 mSv/h in ~75 years.  In-vessel: Li 4 SiO 4, Be and W armour, however, do not meet this target  Li 4 SiO 4 and Be dose entirely due to impurities: Co, Ni, Nb, Mo, Eu, Sm, Gd, Tb, Pt, Ir, Pb, U, Th, Bi, Ag, Cd, Ba, Tl, Co, Nb

15 TW5-TSW-001 final meeting, Culham Science Centre, October 2006 15/17 Results: decay times component / constituent / material10 4 mSv/h100 mSv/h2 mSv/h0.01 mSv/hCI < 1 OB TFC / case rear / 316ss<1d OB TFC / radial plates / 316ss<1d OB TFC / case front / 316ss<1d 2y45y OB TFC / epoxy-glass / 316ss<1d OB TFC / conduits / incoloy<1d OB TFC / cable / SC strand<1d OB VV / rear wall / 316ss<1d 10y45y OB VV / radial plates / 316ss<1d 5y50y>1000y OB VV / front wall / 316ss<1d25y58y>1000y OB LTS / structure / eurofer180d25y50y>1000y OB LTS / neutron shield / WC10d15y55y>1000y blanket / manifold / eurofer15y45y80y>1000y blanket / BZ / eurofer10y35y70y>1000y blanket / BZ / LiPb (5 fpy)120d15y90y>1000y blanket / BZ / LiPb (30 fpy)120d25y>1000y blanket / FW / eurofer15y45y80y>1000y blanket / armour / W5y45y500y>1000y

16 TW5-TSW-001 final meeting, Culham Science Centre, October 2006 16/17Summary Upgrading PPCS work on PPCS-AB and PPCS-B radioactive waste analysis using recent regulations, new nuclear data, improved modelling and realistic recycling scenarios. Assess clearance/refurbishment/recycling potential and interim decay times. Results:  new IAEA levels increase amount of material to recycle;  clearance is achieved within few years (OB) or few decades (IB);  most recycling material below 2 mSv/h after ~75y of decay;  are these acceptable time scales?

17 TW5-TSW-001 final meeting, Culham Science Centre, October 2006 17/17Summary Three key issues to optimise fusion recycling strategy by reducing amount of material, secondary wastes and/or radiological levels:  Segregation of materials  Refurbishment  Impurity control Further work:  Shielding issues, particularly in PPCS-B  Transport requirements?  New categorisation?  Radioactivity build-up due to (a) impurities and (b) reuse. www.fourmilab.ch/earthscr/

18 TW5-TSW-001 final meeting, Culham Science Centre, October 2006 18/17 Fusion materials strategy – open

19 TW5-TSW-001 final meeting, Culham Science Centre, October 2006 19/17 Fusion materials strategy – closed

20 TW5-TSW-001 final meeting, Culham Science Centre, October 2006 20/17 Fusion materials strategy: radiological levels and classification criteria? – simple transport RHR – complex transport


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