1. Oct.18, 20011 Neutron Field and Induced Radioactivity in IFMIF Environment M. Sugimoto(JAERI) IEA International Work Shop on Fusion Neutronics The Kongreshous Baden-Baden, Germany

2. Oct.18, 20012 Contents 1.IFMIF Overview 2.Issues Related to Neutronics and Radiation Safety 3.Source Neutron Characteristics 4.Deuteron Induced Radioactivity 5.Requirements for Neutron Nuclear Data 6.Summary

3. Oct.18, 20013 Test specimen s Deuteron beam Li target D+ 7 Li → ｎ＋ ８ Be or ｎ＋ｐ＋ 7 Li etc. Ｄ - Ｌｉ neutron ~ 14MeV peak IFMIF Overview Neutron Irradiation Field for Fusion Materials Post Irradiation Examination Test Facilities Deuteron Accelerators Li-Target Loops Li-Target Assembly E d : 40 or 32MeV, I d : 250mA (=10MW max) Flux-volume: 500 cm 3 (@> 10 14 n/cm 2 /s)

4. Oct.18, 20014 Issues Related to Neutronics and Radiation Safety Li+d source neutron characteristics (not only TTY for 40 and 32 MeV, DDY is preferable) Materials+d source neutron characteristics (due to beam loss along accelerator and beam line) Deuteron induced radio-activities (Ed<40MeV) Neutron induced radio-activities (Ed<50~60MeV) Neutron shielding and streaming from Test Cell Handling of radioactive materials during operation (lithium, irradiation sample, target assembly, etc.)

5. Oct.18, 20015 Source Neutron Characteristics (1)

6. Oct.18, 20016 Source Neutron Characteristics (2) Extend to Lower Energy Part & at Higher Deuteron Energy up to 40 MeV Recent Measurement at CYRIC (Tohoku Univ., 2000)

7. Oct.18, 20017 Source Neutron Characteristics (3)

8. Oct.18, 20018 Source Neutron Characteristics (4)

9. Oct.18, 20019 Deuteron Induced Radioactivity (1) Recent Measurement at CYRIC (Tohoku Univ., 2000) D.L.Johnson et al.

10. Oct.18, 200110 Deuteron Induced Radioactivity (2)

11. Oct.18, 200111 Deuteron Induced Radioactivity (3) Relative Importance of D-induced radio-activities in Li

12. Oct.18, 200112 Requirements for Neutron Nuclear Data Spectrum Calculation Neutron DDX (especially at low energy and larger scattering angles) Nuclear Heating Calculation Photon production Charged particle production Activation Calculation Long-lived residual production Sequential multi-step reaction process UNIVERSAL REQUESTS IN USE FOR IFMIF NEUTRONICS PROBLEMS e.g. (n,2n), (n,3n) and (n,Xn) (where X=charged particle) processes are important in some calculations (Neutron cross sections up to 50~60 MeV)

13. Oct.18, 200113 Status of Neutron Nuclear Data (n,2n) : Generally good situation except for Be, candidate of multiplier material. (n,3n) : Generally worse. Heavily relied on model calculations. Experimental consistency check is recommended. (n,pn) : Situation is better. Systematic measurement to separate (n,d) process is lacked. (n,  n) : Comparatively worse. No systematic study is found. Partial DDX information for each channel is necessary to establish the clear systematic understanding about channel branching, though its measurement is extremely difficult. Theoretical support calculation which excludes the excessive model parameters is inevitable. Continued systematical measurements of the above reaction cross sections at JAERI/FNS and the other facilities (esp. at higher than 14 MeV) is strongly desired and the results are much useful.

14. Oct.18, 200114 Summary 1.Neutron source characteristics are relatively well-known. 2.Detailed analyses to deduce Double-Differential Yields for mono-energetic deuterons based on the correct theoretical interpretation are needed. 3.Deuteron induced activities might be measured at each laboratory, however, these data are not available in a systematical form. 4.Neutron induced activities are