1. IEA collaboration in fusion neutronics Contributions of TU Dresden Workshop, Baden-Baden, 18 October, 2001 K. Seidel, TUD 1. Experimental validation of shut-down dose rates H. Freiesleben, D. Richter, K. Seidel, S. Unholzer Technische Universität Dresden, Institut für Kern- und Teilchenphysik, Mommsenstr. 13, D-01062 Dresden, Germany Y. Chen 1, U. Fischer Association FZK-Euratom, Forschungszentrum Karlsruhe, Institut für Reaktorsicherheit, P.O. Box 3640, D- 76021 Karlruhe, Germany 1 Institute of Plasma Physics of Chinese Academy of Sciences, Hefei, Anhui, 230031 P. R. China M. Angelone, P. Batistoni, M. Pillon Associazione Euratom-ENEA, Centro Ricerche Energie Frascati, Settore Fusione, Via E. Fermi 27, I-00044 Frascati (Roma), Italy ITER Task T-426

2. IEA collaboration in fusion neutronics Contributions of TU Dresden Workshop, Baden-Baden, 18 October, 2001 K. Seidel, TUD Motivation

3. IEA collaboration in fusion neutronics Contributions of TU Dresden Workshop, Baden-Baden, 18 October, 2001 K. Seidel, TUD Vertical and horizontal cut of the assembly

4. IEA collaboration in fusion neutronics Contributions of TU Dresden Workshop, Baden-Baden, 18 October, 2001 K. Seidel, TUD Irradiation: 1.95·10 15 14-MeV neutrons during 2 days at FNG Time profile of the neutron source strength as recorded during the irradiation (thin line) and as described in the calculations (thick line) for the complete campaign (left hand) and for the last three hours (right hand).

5. IEA collaboration in fusion neutronics Contribution of TU Dresden Detector: tissue-equivalent scintillator(NE 105), 4.6 cm * 4.6 cm ø. Calibration: air-kerma reference value (W/e = 33.97 V) in standard photon fields (19.9 keV... 6.7 MeV) at PTB. Measurement: quasi-continuously with integration intervals from 5 min to 3 h. Dose rate measurement Workshop, Baden-Baden, 18 October, 2001 K. Seidel, TUD

6. IEA collaboration in fusion neutronics Contribution of TU Dresden Workshop, Baden-Baden, 18 October, 2001 K. Seidel, TUD Experimental and calculated dose rate at several decay times Calculation: Rigorous two-step formalism (U. Fischer), MCNP+FENDL/MC-2.0, FISPACT+FENDL/A-2.0 Uncertainties: total experimental 3.9%; statistical uncertainty of about 1% for the calculated values

7. IEA collaboration in fusion neutronics Contribution of TU Dresden Workshop, Baden-Baden, 18 October, 2001 K. Seidel, TUD Flux spectra of decay  -rays Detector: liquid scintillator (NE 213), 3.8 cm * 3.8 cm ø Response: matrix of pulse-height distributions on absolute scale; unfolding with DIFBAS code (PTB) Structure of the spectra: flux in the cavity at t= 4380 s per one  -ray started in SS316, calculated with the FISPACT energy groups (blue) and with  E = 0.01 MeV

8. IEA collaboration in fusion neutronics Contribution of TU Dresden Workshop, Baden-Baden, 18 October, 2001 K. Seidel, TUD

9. IEA collaboration in fusion neutronics Contribution of TU Dresden Workshop, Baden-Baden, 18 October, 2001 K. Seidel, TUD

10. IEA collaboration in fusion neutronics Contribution of TU Dresden Workshop, Baden-Baden, 18 October, 2001 K. Seidel, TUD

11. IEA collaboration in fusion neutronics Contribution of TU Dresden Workshop, Baden-Baden, 18 October, 2001 K. Seidel, TUD Measured flux of the  -rays with E > 0.4 MeV in comparison to the calculations Calculation: rigorous two-step method (U. Fischer), MCNP+FENDL/MC-2.0, FISPACT+FENDL/A-2.0. Uncertainties: total experimental, statistical only of the calculation

12. IEA collaboration in fusion neutronics Contribution of TU Dresden Workshop, Baden-Baden, 18 October, 2001 K. Seidel, TUD Neutron flux spectrum Vertical cut of the assembly with NE 213 detector Fluence per one source neutron for E > 13.7 MeV, Experiment: (5.91  0.35)·10 -5 Calculation: (5.96  0.32)·10 -5 ———————————————— C/E = 1.01  0.07

13. IEA collaboration in fusion neutronics Contribution of TU Dresden Workshop, Baden-Baden, 18 October, 2001 K. Seidel, TUD Results Gamma dose rates measured in a materials mock-up of the ITER shielding system with an uncertainty of about 4% over a period of three weeks after irradiation of the assembly with 14-MeV neutrons are consistent with the flux spectra of the decay  -rays measured in that period. Rigorous two-step calculations with the MCNP code, using FENDL/MC-2.0 data, and with the FISPACT code, using FENDL/A-2.0 data, result in ratios of calculated-to-experimental values of C/E = 0.80... 1.08 for both dose rates and  -flux, if material composition and irradiation scenario are described in detail. Underestimation of experimental values of 10... 20% is observed for the first week of decay, whereas overestimation up to 8% is obtained at the end of the campaign. ITER design calculations for similar assemblies and decay times with the codes and the data libraries, used in this task, have been validated within that uncertainties. Experimental data and calculated results may be used for investigating other (faster, simpler, approximate) calculation schemes.

14. IEA collaboration in fusion neutronics Contribution of TU Dresden Workshop, Baden-Baden, 18 October, 2001 K. Seidel, TUD 2. Experimental investigation of radioactivity induced in the fusion power plant structural material EUROFER and in other steels by D-T neutrons K. Seidel a, R. A. Forrest b, H. Freiesleben a, V. D. Kovalchuk c, D. V. Markovskij d, D. V. Maximovich c, and S. Unholzer a a Technische Universität Dresden, Institut für Kern- und Teilchenphysik, 01062 Dresden, Germany b EURATOM/UKAEA Fusion Association, Culham Science Centre, Abingdon OX143DB, United Kingdom c Coordination Centre ”Atomsafety”, 141300 Sergiev Posad, Moscow Region, Russia d Russian Research Centre ”Kurchatov Institute”, 123182 Moscow, Russia Contribution to 10 th International Conference on Fusion Reactor Materials, Baden-Baden

15. IEA collaboration in fusion neutronics Contribution of TU Dresden Workshop, Baden-Baden, 18 October, 2001 K. Seidel, TUD 3. SiC benchmark experiment SiC assembly shipped from JAERI/FNS to Frascati TUD measurements in September 2001: Neutron flux spectra with NE213 spectrometer and hydrogen-filled proportional counter at 4 positions for E = 50 keV.... 15 MeV Gamma flux spectra with NE213 spectrometer at 4 positions for E = 20 keV.... 12 MeV