1. Study on recycling of fusion activated materials: Identify activation levels, characteristics and decay time requirements of irradiated material (deliverable 3) R Pampin, R Bestwick EURATOM/UKAEA Fusion Association AMEC-NNC Ltd TW5-TSW-001 monitoring meeting CEN-SCK Mol, June 2006

2. TW5-TSW-001 monitoring meeting, CEN-SCK Mol, Belgium, June 2006 2/13Background European Fusion Programme strategy for fusion irradiated waste:  Release from regulatory control of 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the rest PPCS radioactive waste results: all material cleared/recycled within 100 years, but:  Release criteria: out-of-date IAEA clearance levels (1996)  Lack of detail in the models (e.g. outer components)  Inadequate modelling of particular materials (e.g. LiPb)  Recycling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 monitoring meeting, CEN-SCK Mol, Belgium, June 2006 3/13Background PPCS recycling criteria: some sensible for certain waste streams following certain routes (e.g. re-melting of steels); “complex recycling” limit is crucial but: (a) noticeably over-conservative and (b) 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

4. TW5-TSW-001 monitoring meeting, CEN-SCK Mol, Belgium, June 2006 4/13Background IAEA 1996/2004 clearance levels: many changes affect fusion- relevant radionuclides (e.g. 30-fold decrease in Ni-63 level).

5. TW5-TSW-001 monitoring meeting, CEN-SCK Mol, Belgium, June 2006 5/13 Scope and objectives To review and update PPCS work using:  Up-to-date international clearance regulations: IAEA 2004  Up-to-date nuclear data: EAF 2005.  Practical recycling criteria: findings of this task.  More accurate modelling methodology (e.g. LiPb flow) and increased level of detail (e.g. TFC materials). With the aim of:  Determining more realistic amounts and description of waste according to actual processing routes.  Identifying interim decay times required before recycling.  Identifying potential for (a) reduction of waste, and (b) simplification of recycling processes.

6. TW5-TSW-001 monitoring meeting, CEN-SCK Mol, Belgium, June 2006 6/13 Computational tools and models HERCULES code automates 2D geometry + material modelling of tokamak power plants, coupling:  MCNP neutron transport  FISPACT transmutation + EAF libraries W armour vessel TF coil breeder zone manifold LT shield HT shield PPCS-AB HERCULES model.

7. TW5-TSW-001 monitoring meeting, CEN-SCK Mol, Belgium, June 2006 7/13 Computational tools and models vessel TF coil (a)(b)(c) (d) (e) (f) (a)VV front casing  316ss (b)VV radial plates  316ss (c)VV rear casing  316ss (d)TFC front casing  316ss (e)TFC winding pack  316ss, SC cable, incoloy, epoxy (f)TFC rear casing  316ss a b c d e f PPCS

8. TW5-TSW-001 monitoring meeting, CEN-SCK Mol, Belgium, June 2006 8/13 Preliminary results New IAEA levels  increased amounts of material to be recycled: OB VV and IB TFC. Segregation alleviates this.

9. TW5-TSW-001 monitoring meeting, CEN-SCK Mol, Belgium, June 2006 9/13 Preliminary results Cooling times of PPCS-AB and PPCS-B individual constituents and materials and average components; in preparation. PPCS-AB IB TFC2 mSv/h0.01 mSv/h rear case< 1y rad plates< 1y25y front case1y45y SC strand< 1y10y incoloy<1y35y epoxy-glass< 1y average< 1y30y

10. TW5-TSW-001 monitoring meeting, CEN-SCK Mol, Belgium, June 2006 10/13 Preliminary results PPCS-AB results (general):  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 seems imperative  reuse in fusion plant?

11. TW5-TSW-001 monitoring meeting, CEN-SCK Mol, Belgium, June 2006 11/13 Preliminary results PPCS-AB results: 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

12. TW5-TSW-001 monitoring meeting, CEN-SCK Mol, Belgium, June 2006 12/13 Preliminary results PPCS-B results (general):  In-vessel: again, 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: control of these would meet target Co, Ni, Nb, Mo, Eu, Sm, Gd, Tb, Pt, Ir, Pb, U, Th, Bi, Ag, Cd, Ba, Tl, Co, Nb

13. TW5-TSW-001 monitoring meeting, CEN-SCK Mol, Belgium, June 2006 13/13Summary 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/recycling potential and interim decay times. Results:  new IAEA levels increase amount of material to recycle.  PPCS analyses over-conservative: most material suitable for “simple-recycling” after < 75y cooling time.  control of impurities crucial, not only in steels but also for e.g. Be and Li 4 SiO 4 : requirements being developed. Further input: definition of “non-simple” recycling routes and radiological criteria. Draft report & radiological data available shortly raul.pampin@ukaea.org.uk