RADIOACTIVITY MEASUREMENTS OF ITER MATERIALS USING THE TFTR D-T NEUTRON FIELD

The availability of high D-T fusion neutron yields at TFTR has provide d a useful opportunity to measure directly D-T neutron-induced radioac tivity in a realistic tokamak fusion reactor environment for materials of vital interest to ITER. These measurements are valuable for charac terizing radioactivity in various ITER candidate materials, for valida ting complex neutron transport calculations, and for meeting fusion re actor licensing requirements. The radioactivity measurements at TFTR i nvolve potential ITER materials including stainless steel 316, vanadiu m, titanium, chromium, silicon, iron, cobalt, nickel, molybdenum, alum inum, copper, zinc, zirconium, niobium, and tungsten. Small samples of these materials were irradiated close to the plasma and just outside the vacuum vessel wall of TFTR, locations of different neutron energy spectra. Saturation activities for both threshold and capture reaction s were measured. Data from dosimetric reactions have been used to obta in preliminary neutron energy spectra. Spectra from the first wall wer e compared with calculations from ITER and with measurements from acce lerator-based tests.