Validation analyses of IEAF-2001 data

1. Validation analyses of IEAF-2001 data S.P. Simakov, U. Fischer Association Euratom-FZK, Institut für Reaktorsicherheit, Forschungszentrum Karlsruhe GmbH, Germany P. Bém, V. Burjan, M. Götz, M. Honusek, V. Kroha, J. Novák, E. Šimečková Association Euratom-IPP/NPI.CR, Nuclear Physics Institute, Řež , Czech Republic IAEA Technical Meeting “Nuclear Data for the IFMIF”, Forschungszentrum Karlsruhe, 4-9 October 2005

2. Content Two activation experiments with white energy spectra exceeding 20 MeV were analyzed: • IRS/FZK (U. von Möllendorff et al.): d(40 MeV)-Li white neutron source extending up to 55 MeV, SS-316, F82H, V, V-alloys • NPI/Řež (P. Bem et al.): p(37 MeV)-D2O white neutron source extending up to 35 MeV, Eurofer-97, W, Ta (now under analyses) Objectives – validation activation cross sections libraries and inventory codes: • IEAF-2001 (up to 150 MeV) + ALARA inventory code • EAF-2005 (up to 55 MeV) + FISPACT inventory code IAEA IFMIF Data Meeting, Karlsruhe

3. Neutron Detector Activation Foils 37 MeV protons 2.3-2.7 mm ≈ 700 cm D2O Target (Ø30×26 mm2) Set-up and MCNPX simulation of NPI/Řež Activation Experiment Target and Foils Assembly (MCNPX model) p-beam profile in heavy water INP/Rez activation experiment can not be represented by a point-like-geometry: the neutron spectrum measured by NE-detector can’t be transformed to foils spot just by scaling IAEA IFMIF Data Meeting, Karlsruhe

4. p-D2O Neutron Source Simulation Energy-Angular Neutron Yield, Ep=37MeV DDX for D(p,xn) reaction • MCNPX/LA150h fails to predict p-D2O neutron spectrumsince LA-150h does not represent DDX for the D(p,xn) reaction IAEA IFMIF Data Meeting, Karlsruhe

5. Irradiation History and n-Flux vs. Target to Sample Distance Modelling Proton Beam Time Profile (W) 27Al(n,a)24Na Reaction Rate vs. Distance 3-pulses approximation was used for representation of irradiation history 27Al(n,x)24Na reaction rate is used for renormalization n-flux at diff. points IAEA IFMIF Data Meeting, Karlsruhe

6. Status of 27Al(n,x)24Na Reaction Cross Section above 20 MeV(a “standard” below 20 MeV) 27Al(n,x)24Na and (n,x)4He reactions cross sections Reactions thresholds • ENDF/B6.8 - discontinuity between XS from MT107 and MT5 at 20 MeV ! • IEAF-2001 - underestimation below 20 MeV • Disagreement of evaluat. and measured 24Na production XS above 20MeV(only one available Louvain’2000 experiment looks wrong ?) IAEA IFMIF Data Meeting, Karlsruhe

7. Neutron Spectrum Determination from Activity of Dosimetry Foils (method) Example of dosimetry XS. Unfolding Code: modified SAND-II 9 dosim. foils and 23 reactions: 27Al - (n,x)24Na 197Au - (n,g), (n,2n), (n,3n), (n,4n) 93Nb - (n,2n) 93Y – (n,g), (n,2n) 59Co – (n,p), (n,a), (n,2n), (n,3n) Ti – (n,x)46Sc, (n,x)47Sc, (n,x)48Sc Ni – (n,x)57Co, (n,x)58Co, (n,x)60Co Fe – (n,x)54Mn, (n,x)56Mn, (n,x)51Cr Lu – (n,x)173Lu, (n,x)174Lu XS data libraries: EAF-2005 (< 55 MeV), IRDF-2002 (< 20), ENDF-B6 (< 20-30) - dosimetry reactions cross sections need measurements above 20 MeV - uncertainties need to be estimated IAEA IFMIF Data Meeting, Karlsruhe

8. Neutron Spectrum Determination from Activity of Dosimetry Foils (results) Energy-Linear Scale Energy-Logarithmic Scale Additional dos. reactions are needed to cover the energies: above 25 MeV – 209Bi(n,2-6n); 1-10 MeV – 115In, 93Nb, 103Rh(n,n’); below 1MeV – X(n,g) ? IAEA IFMIF Data Meeting, Karlsruhe

9. C/E ratios for specific radionuclides generated in the Steels using IEAF-2001:NPI/Rez for EF-97 (p-D2O, < 35 MeV) vs. FZK for SS-316, F82H (d-Li, < 55MeV) - C/E ratios mainly concentrate around 1 except several large deviations; - both FZK and NPI show large deviation from 1 for: 47Sc, 48V, 52Mn, 184Ta IAEA IFMIF Data Meeting, Karlsruhe

10. C/E ratios for specific radionuclides generated in EF-97 steel (NPE/Rez):EAF-2005 vs. IEAF-2001 - Major C/E ratios improve using EAF-2005 instead of IEAF-2001 (46Sc,47Sc,52Mn,177Ta, 184Ta) - 56Co produced predominantly by SCPR mechanism (Fe(p,n), as FISPACT/EAF-2005 shows) IAEA IFMIF Data Meeting, Karlsruhe

11. Analyses of C/E and difference for 52Mn inventory in Steels 54Fe(n,x)52Mn Cross Sections C/E for 52Mn Activity: IEAF-2001: C/E = 3.60 (EF-97, Rez)C/E = 3.29 ± 0.41 (SS-316, FZK)C/E = 3.86 ± 0.21 (F82H, FZK EAF-2005: C/E = 1.05 (EF-97, Rez) EAF-2005 better represents 54Fe(n,x)52Mn activation cross sections than IEAF-2001 IAEA IFMIF Data Meeting, Karlsruhe

12. Analyses of C/E and difference for 52Fe inventory in Steels 54Fe(n,3n)52Fe Cross Sections C/E for 52Fe Activity: IEAF-2001: C/E = 0.35 (EF-97, Rez)C/E = 1.48 ± 0.74 (SS-316, FZK)C/E = 1.36 ± 0.27 (F82H, FZK EAF-2005: C/E = 3.97 (EF-97, Rez) Status of 54Fe(n,3n)52Fe activation cross section is not yet clear: Rez and FZK benchmarks demand decreasing of EAF-2005, whereas it agrees with Tohoku’ XS IAEA IFMIF Data Meeting, Karlsruhe

13. C/E ratios for radioactvities generated in Tungsten (NPI, E = 0 - 35 MeV):IEAF-2001 in comparison with EAF-2005 0.5 < C/E < 2: for 5 isotopes (IEAF-2001) and for 9 isotopes (EAF-2005) IAEA IFMIF Data Meeting, Karlsruhe

14. Analysis of the reasons for large C/E deviation from 1 for 182mHf (W Activation Experiment in NPI/Rez) 186W(n,nα)182mHf Cross Section C/E for 182mHf Activity IEAF-2001: C/E = 420 EAF-2005: C/E = 1.6 First benchmark for 182mHf ! NPI/Rez experiment indicates 400 times overestimation of 186W(n,nα+)182mHf cross section in IEAF-2001 and confirms EAF-2005. No measurements for this reaction cross sections are available ! IAEA IFMIF Data Meeting, Karlsruhe

15. Conclusions • D(p,xn) double differential cross section (presently available only in LA-150 library) needs re-evaluation • While evaluated activation reactions cross sections are relatively well represented in EAF-2005 and IEAF-2001 libraries up to 20MeV, above this energy they still need experimental validation by monoenergetic and white neutron sources. • Dosimetry reactions cross sections and its uncertainties need extension above 20 MeV IAEA IFMIF Data Meeting, Karlsruhe