IEA International workshop on Fusion Neutronics 18 October 2001, Baden-Baden (Germany)

1. IEA International workshop on Fusion Neutronics • 18 October 2001, Baden-Baden (Germany) • ENEA Activity in 2001 • P. Batistoni • Shut Down Dose Rate Experiment for ITER (T-426) • Experimental Validation of EFF/EAF Nuclear Data Libraries (EU Technology Program TTMN-002) • Decay heat measurements on EUROFER and other materials • Benchmark experiment on SiC

2. ITER Task T426 – EU SHUT DOWN DOSE RATE EXP. for ITER Objective : verify shut down dose rate calculation for ITER out-vessel, in-cryostat for tcool1 month Mock-up irradiated at FNG (3 days) to have a detectable dose rate (ENEA, TUD, FZK)

3. ITER Task T426 – EU SHUT DOWN DOSE RATE EXP. for ITER – ANALYSIS R2S method D1S method

4. ITER Task T426 – EU SHUT DOWN DOSE RATE EXP. for ITER – RESULTS CONCLUSIONS The shut down dose rate outside the ITER vessel is calculated by 2-step method R2S (MCNP/FISPACT) and by 1-step method D1S (MCNP-modified), using and FENDL-2 data, within 15% from a few days up to 2 months of decay time

5. ITER Task T426 – EU SHUT DOWN DOSE RATE EXP. for ITER – RESULTS The Ni-58(n,p)Co-58 and Ni-58(n,2n)Ni-57 reaction rates were directly measured during irradiation, and calculated using both the R2S method and the D1S method • Ni-58(n,p): using FISPACT with FENDL/A–2 (R2S), C/E slightly higher than unity, while those obtained with direct MCNP calculation (D1S) using IRDF-90 and FENDL/MC–2 generally lower and in better agreement with the measurements. • Ni-58(n,2n): using the direct MCNP calculation (D1S) with IRDF-90 and FENDL/MC–2, C/E very close to unity. Using FISPACT with FENDL/A–2 (R2S), C/E about 1 - 3% lower than in the previous case.

6. 1.5 C/E 1.0 0.5 0.0 • Beta power • Gamma power Beta power Gamma power C/E EUROFER 1.5 Decay time (hours) Decay time (hours) 1.0 0.5 0.0 1 10 100 1000 EU Fusion Technology Program – Nuclear Data Experimental validation of EAF activation cross sections • Detecting system developed to measure simultaneously the total activity of a neutron irradiated material and the electron and photon decay heats • Activation/decay heat in EUROFER g- and b-decay heat measured up to tcool~ 20 days,g- activity measured up to several months of cooling time Deficencies in beta decay heat identified in the comparison with EAF predictions

7. EU Fusion Technology Program – Nuclear Data Experimental validation of EAF activation cross sections • Decay heat in 12 materials (Cu, Ag, Sn, Cd, Mg, Hf, Mo, Al, Ti, Ni, W, Re) g- and b-decay heat measured and compared with EAF predictions Some deficencies identified in EAF • Activation/decay heat in Cr and other materials is in progress (2001 activity)

8. EU Fusion Technology Program – Nuclear Data Validation of EFF cross sections for advanced materials . SiC EXPERIMENT at FNG (2000-2001) (ENEA, TUD,FZK, IJS) Objective Provide validation of EFF data for Silicon carbide which is a candidate low activation material for the fusion reactor, and is considered for development in the European Fusion Technology Program (SiC block on loan from JAERI within IEA collaboration)

9. EU Fusion Technology Program – Nuclear Data Validation of EFF cross sections – SiC experiment • Measurements (already completed) • neutron and gamma spectra (TUD) • Activation (ENEA) • Gamma heating (ENEA) • Analysis (in progress) • C/E for all measured quantities for EFF (and FENDL-2) libraries • Sensitivity /uncertainty analysis based on 3D MC and 2D deterministic approaches

10. EU Fusion Technology Program – Nuclear Data Validation of EFF cross sections – SiC experiment • Preliminary analysis on fast neutron flux measurements show a significant difference between EFF(2.4) and FENDL-2 • Analysis will be performed with new Si and C evaluation in EFF as soon as processed data will be available • Analysis could also be performed using JENDL-FF in the frame of IEA collaboration • Benchmark experiment on W planned in 2002