HTGR Knowledge Base

Conference Article: The application of release models to the interpretation of rare gas coolant activities

Abstract

Much research is carried out into the release of fission products from UO₂ fuel and from failed pins. A significant application of this data is to define models of release which can be used to interpret measured coolant activities of rare gas isotopes. Such interpretation is necessary to extract operationally relevant parameters, such as the number and size of failures in the core and the ¹³¹I that might be released during depressurization faults. The latter figure forms part of the safety case for all operating CAGRs. This paper describes and justifies the models which are used in the ANAGRAM program to interpret CAGR coolant activities, highlighting any remaining uncertainties. The various methods by which the program can extract relevant information from the measurements are outlined, and examples are given of the analysis of coolant data. These analyses point to a generally well understood picture of fission gas release from low temperature failures. Areas of higher temperature release are identified where further research would be beneficial to coolant activity analysis.

view the full text of this article (15 pages, format: PDF, size= 688kB)

Reference:

Specialists' meeting on fission product release and transport in gas-cooled reactors Berkeley (United Kingdom) 22-25 Oct 1985

International Atomic Energy Agency, International Working Group on Gas-Cooled Reactors, Vienna (Austria)

IWGGCR--13, pp:221-235