Fast Reactors and Accelerator Driven Systems Knowledge Base

Conference Article: The objectives of design stage hot-spot analysis

Gatley, J.A. (Nuclear Power Group Ltd., Risley (UK))

Abstract

The fundamental objective in designing a commercial fast reactor is to produce a power station which can generate a certain electrical output power without exceeding any of the defined operational limits. The limit of first interest for core design is the hotspot criterion. It is advantageous to increase the maximum fuel burn-up and, usually, the maximum fuel can temperatures: the extent to which these objectives can be achieved is limited by the incidence of failed fuel ins, and the calculational technique should therefore be capable of being related to failed pin frequencies. Two calculational approaches are discussed: the first extrapolates pin conditions to obtain a “representative temperature” at a national target burn-up, which is used for assessing the probability of certain numbers of pins failing before reaching that burn-ups; and the second concentrates on the degree of risk of having failed pins actually present in the reactor at any particular time of interest. This is referred to as the “instantaneous” approach. The form of hotspot limiting criterion used depends on the approach used. It is pointed out that any calculation should be relatable to early irradiation data and should be able to accommodate practical variations in fuel cycle and gagging policy.

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key words: fast reactors; fuel cans; heat transfer; hot spots
Reference:
Summary report of a panel meeting held in Karlsruhe, 22-24 November 1973 on the recommendation of the International Working Group on Fast Reactors. 1974. p. 133-142
International Atomic Energy Agency, Vienna (Austria)
IAEA-TECDOC--166, pp:110-113