IRRADIATION CREEP OF CANDIDATE MATERIALS FOR THE FIRST WALL OF A FUSION REACTOR
An apparatus has been constructed to study the irradiation creep behaviour of candidate materials for the first wall of a fusion reactor under proton or deuteron irradiation from a cyclotron. A cylindrical specimen of 130-150 microns diameter is stressed in torsion. The strain is measured by an optically coupled system which has a resolution of 1/1000 degree corresponding to a nominal shear strain resolution of 10**-7 for a typical specimen configuration. The specimen is cooled by a high purity helium jet directed perpendicularly to the specimen axis. At helium velocities of ca 400 m/s cooling rates of 500 W/cm**2 were measured indicating that under irradiation displacement rates of 1.5 dpa/day are possible. In addition to the beam heating the specimen will be heated by a direct current regulated by a feed back system in order to compensate for beam fluctuations. The feed back system receives its signal from an infrared pyrometer. The specimen temperature is measured with a second pyrometer. The beam intensity is determined by two independent methods. The first one is the faraday cup measurement of the beam current which passes through a known area formed by four collimators. The second method involves the dc heating of the specimen. The beam intensity can be calculated by the drop in dc heating when the beam is turned on. Creep rate measurements of stainless steel type 316 L under 19 MeV deuteron irradiation as function of stress temperature and particle flux are currently in preparation. It is planned to measure the effect of cyclic stress, cyclic temperature and pulsed irradiation on the creep behaviour of this material. The microstructure which develops during irradiation will be investigated with TEM.
Bibliographic Reference: 13TH SYMPOSIUM ON FUSION TECHNOLOGY, VARESE (ITALY), SEPT. 24-28, 1984 WRITE TO CEC LUXEMBOURG, DG XIII/A2, POB 1907, MENTIONING PAPER E 31722 ORA
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Record Number: 1989123025200 / Last updated on: 1987-01-01
Available languages: en