Neutron irradiation tests on diagnostic components at JAERI

As a part of the R&D program of the ITER Engineering Design Activities (EDA), we have carried out irradiation tests on a number of diagnostic components. In this paper the recent results of neutron irradiation tests on diagnostic windows, bolometer substrates and magnetic coils at JAERI are described. UV range transmission losses of a KU-1 quartz glass were measured during 14 MeV neutron irradiation at the Fusion Neutronics Source (FNS) with neutron fluences of up to 7.4×1019 n/m2. Significant transmission losses were observed in the wavelength of 200–300 nm. Mica substrates of bolometers were irradiated at the Japan Material Testing Reactor (JMTR) with neutron fluence between 1×1022 and 2.2×1023 n/m2. The size expansion was found to be only 0.13% at 2.2×1023 n/m2 and 150 °C, which gives us the good prospect of the bolometer in the ITER-FEAT application. Magnetic coils made with four kinds of Mineral Insulated (MI) cables have been irradiated in JMTR up to a fast neutron fluence of 1.1×1024 n/m2. Radiation Induced Electrical Motive Force (RIEMF) of several volts was observed between core inductor and sheath of the MI cable.