Results of irradiation tests of KU-1 and KS-4V silica glasses as ITER candidate window materials

摘要

Previous irradiation tests have shown that KU-1 silica glass may be used for ITER diagnostic windows in the spectral region of 0.35-2.5 μm. To help clarify the possibility of increasing this spectral range to the UV region irradiation tests of KS-4V high purity silica in Co~(60) gamma source and nuclear reactor were undertaken. KS-4V has an order of magnitude lower induced absorption in UV range compared with KU-1 after gamma irradiation up to 3 MGy, but there is no marked difference in transparency of KU-1 and KS-4V silica glasses after reactor irradiation up to F_(>0.1) ≈ 3 x 10~(16) n/cm~2 (D_γ ≈ 1 MGy) although induced absorption of KS-4V is slightly lower. In situ tests of transparency degradation under neutron and gamma irradiation of KU-1 and KS-4V silica glasses in UV range will be necessary for final clarification and ITER database preparing.