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Title: Radiation-induced degassing of cryopumps

Conference ·
OSTI ID:6848940

The pressure-gauge response of the system to the TRIGA pulses is shown. With an unloaded cryopump, an apparent pressure pulse is produced which is only slightly longer than the reactor pulse itself. In separate experiments, it was found that a similarly appearing pulse is produced by a completely sealed-off vacuum gauge. With a deuterium-loaded cryopump, a very much larger pressure pulse was produced, which had a long exponential tail, characteristic of a re-pumpdown of the system. The pumping speed, as computed from the exponential, is about half that observed previously when the cryopump was subjected to D/sub 2/-gas pulses, in the absense of radiation. Additional experiments were run with the core of the reactor retracted somewhat into the pool, in order to change the mix of gamma rays, thermal neutrons, and fast neutrons so as to preferentially depress the latter.

Research Organization:
California Univ., Berkeley (USA). Lawrence Berkeley Lab.
DOE Contract Number:
W-7405-ENG-48
OSTI ID:
6848940
Report Number(s):
LBL-7941; CONF-781105-18; TRN: 79-001690
Resource Relation:
Conference: ANS meeting, Washington, DC, USA, 12 Nov 1978
Country of Publication:
United States
Language:
English