Tritium Retention in Jet Cryopanel Samples

Abstract

This paper discusses the possibility that tritium might exchange with water trapped in aluminum anodize cryopanels in JET which prompted a test program at the Tritium systems Test Assembly, TSTA. Los Alamos, New Mexico. JET furnished two test pieces of cryopanel which were exposed to tritium at approximately liquid nitrogen temperature and 25 torr pressure for nearly two weeks. One specimen was removed and the retained tritium was measured. The second specimen was subjected to several increasing temperature vacuum bakeouts and the effectiveness of the bakeouts were inferred from the pressure history of the chamber. When the retained tritium in the second specimen was measured, it was found that nearly 96% of the tritium, as measured in the first specimen, had been removed during the vacuum bakeouts. If the tritium retained in the cryopanel without bakeout were scaled to JET conditions according to a linear pressure-time relationship, the tritium expected to become trapped in the JET cryopanels would be approximately 0.6 gram.