返回Google圖書搜尋

Relocation of molten zircaloy in diluted steam

出版	Atomic Energy Of Canada Limited, 1997
URL	http://books.google.com.hk/books?id=oRRo0AEACAAJ&hl=&source=gbs_api

註釋In-core flux detectors (icfds), also known as self-powered neutron detectors, are key elements in candu reactor control and safety. at present, no firm criteria are in place to determine when an icfd should be replaced. detector performance is assessed in a qualitative way by an engineer using the combined results of insulation resistance measurements, rundown tests, operator observations and, recently, noise analysis. there is concern that life-limiting mechanisms in icfds could lead to multiple failures in a short timespan, thereby forcing a unit out of service because of an inadequate number of spare icfds. also, avoiding premature replacement of icfds and timing their replacement to coincide with planned outages has definite operations, maintenance, and administration (om&a) cost-reduction advantages. thus methods of predicting when the end-of-life of an icfd is likely to occur and deciding in a quantitative way when a suspect icfd should be replaced will facilitate om&a cost reduction. one of the end-of-life mechanisms is burnout of the current-producting materials in the detector. burnout affects both the sensitivity and the dynamic response of a detector. thirteen prototype straight individually replaceable (sir) icfds have been irradited in the nru core since 1981. measurements of the sensitivity and dynamic response of these detectors were done in 1990 may and 1995 january. these measurements are combined with earlier reported measurements to compare the long-term changes in sensitivity and dynamic response with the predicted changes. the results indicate that sir detectors should not suffer any burnout-related failures for a period of at least the 14 years of the detectors in the study.