Activity of Fusion Neutronics Sub-task from October 2000 to September 2001

1. Activity ofFusion Neutronics Sub-task from October 2000 to September 2001 Presented by Takeo Nishitani Leader of the Fusion Neutronics Sub-task ExCo of IEA Fusion Reactor Nucl. Technology Baden-Baden, Germany, 19th October, 2001

2. Major contribute in this sub-task • European Community • FZK, TU Dresden, UP Madrid, ENEA frascati • Japan • JAERI and Osaka University • USA • UCLA, et al. • Russia • Kurchatov, et al.

3. Fusion Neutronics Activity at JAERI from October 2000 to September 2001 • Breeding Blanket Experiments • Shielding benchmark experiments • Shutdown dose measurements • Double bent duct streaming experiment • Decay heat measurements • Activation Experiments for Sequential Charged Particle Reactions • Development of Neutron Measurement Technique • Development of Artificial Diamond Detector • Development of Micro Fission Chamber for ITER

4. Breeding Blanket ExperimentsTo verify the nuclear performances of resent designed thermal blankets. Detectors (NE213) FNS 80deg. D-T target A blanket assembly Shielding (Li2CO3) A schematic view of FNS blanket experiments

5. Preliminary Result We have obtained the profile of reaction rates of the iron, chromium and tungsten in F82H and tritium production in 95-% Li2TiO3. C/E of the 95-% Li2TiO3 tritium production is closed to 1 with the error of plus and minas 10%. However, since experimental result of activities of Au foil in Be is significantly underestimated, The investigation of the cause is in progress. The profiles of reaction rates at the assembly

6. 9.0 3.5 Reflector (SS316) Source Reflector (SS316) Shield (SS316/H20) 8.0 3.0 7.0 6.0 2.5 5.0 Shutdown dose rate（mSv/hr） 2.0 300 #a #b #c 800φ 4.0 1200φ 200 3.0 1.5 #A #B #C 356 2.0 1.0 1.0 0.0 0.5 1.0 3.0 5.0 7.0 9.0 11.0 13.0 15.0 D-T source Test region Cooling time (x 105sec) Shutdown dose measurements • Shutdown dose rates can be evaluated by the new one step method within experimental error (~10%) FENDL/2A FENDL/2 #A #a Cross sectional view of the assembly Comparison of shutdown dose rates

7. Auxiliary Shield 550 750 1200 Streaming Assembly #6 DT Source #1 #2 #3 Duct Opening (300 x 300) 1700 900 1000 #4 #5 800 150 565 765 Auxiliary Shield Iron Rack 335 1800 200 Double bent duct streaming experiment • Typical streaming effects can be reproduced by MCNP & FENDL/2 (~30%) Calculation #3 Experiment #4 #6 Neutron flux (n/cm2/source/lethargy) #5 Energy (MeV) Cross sectional view of the assembly Comparison of neutron spectrum

8. Development of Artificial Diamond Detector • Recently, we tried to use a chemical vapor deposition (CVD) diamond with single crystal. • The detector has an energy resolution of 0.4 % for 5.486 MeV  particles, which gives us a good prospect to the 14 MeV neutron spectrometer using a single crystalline CVD diamond. CVD diamond 5.486 MeV particles 0.4 % Polycrystalline Single crystalline

9. Future Plan in Fusion Neutronic at FNS/JAERI • Extend of Breeding Blanket Experiments • Breeder and Beryllium pebbles • Activation Experiments for Sequential Charged Particle Reactions • Development of Neutron Measurement Technique • Development of Neutron Detector using Optical Fiber • Development of Artificial Diamond Detector

10. Fusion Neutronics Activity at Osaka Universityin 1999-2000 • Differential experiments: • Charged particle emission DDX • Gamma-ray production cross section • (n,2n) reaction cross section with a beam source • Integral experiments: • Leakage gamma-ray spectra from slabs • Secondary gamma-ray skyshine

11. Measurements of double differential cross sections for charged particle emission reactions by 14 MeV neutrons. • Samples:natSi and 19F • Facility:OKTAVIAN, pulsed neutrons • Method:2-dimensional analysis of energy and time-of-flight (E-TOF) • Compound samples were successfully employed for light element measurements • Agreement is not good with the evaluated nuclear data for both elements. The DDX and EDX data for 19F(n,xp) reaction

12. Measurements of secondary gamma-ray production cross sections with Hp-Ge detector induced by 14 MeV Neutrons. • Samples:natSn • Facility: OKTAVIAN, pulsed neutrons • Method: TOF-gated PHS analysis • Discrete and continuum components were successfully extracted from the measured pulse height spectrum (PHS) with Hp-Ge (the results were still preliminary). • The present data are the first measured discrete gamma-ray production cross sections for natSn.

13. (n,2n) reaction cross section measurement with a beam DT neutron source • For 55Mn, the measured (n,2n) cross section was in good agreement with the experimental value obtained by the activation method. • Samples:55Mn (to check the system) • Facility:FNS, pencil beam neutrons • The method to directly measure the spectra of two neutrons emitted from (n,2n) reaction has been established.

14. Fusion neutronics benchmark experiment - leakage gamma-ray spectrum measurement - • Samples:LiAlO2, Li2TiO3, Li2ZrO312C, 51V, natFe, natCu, natPb, natW, • Facility:FNS, pulsed neutrons • Result: natV: Underestimation of all the nuclear data files. natFe: Overestimation of JENDL -3.2. natPb: Reproduction is not good for JENDLs 16O: 6 MeV peak is not reproduced by JENDLs.

15. Secondary gamma-ray skyshine from 14 MeV neutron source facility • Facility: FNS, DC neutrons (～1x1011) • Detector: NaI(5”x5”,8”x8”), Hp-Ge(40%) • Clean skyshine benchmark data can be obtained up to 1000 m from the neutron source. • Preliminary experiment has been done under the plug-in condition (the plug is just above the source and on the ceiling) at 140 m from the facility.