Fast Reactors and Accelerator Driven Systems Knowledge Base

Conference Article: A simple analytical method to evaluate transient behaviours of metal fueled fast reactors

Ninokata, H.; Hizume, Y.; Sawada, T.; Endo, H. (Research Laboratory for Nuclear Reactors, Tokyo Institute of Technology, Tokyo (Japan))

Abstract

Through our experiences in transient calculations using a general purpose transient system analysis code, the thermal hydraulic and nuclear responses of a typical metal fueled fast reactor core against UTOP and ULOF are found to be approximated by quasi-steady state representation. With these observations transient fuel and coolant temperature distributions in the core are given by simple algebraic expressions. The influences of temperature dependence of material properties are discussed. With these temperature predictions under typical ATWS conditions, effective reactivity changes due to sodium coolant and fuel temperature changes are found to have a unique linear relationship under the extreme conditions of sodium boiIing as well as fuel failures. On the basis of these limiting relations, passive shutdown or power stabilization capabilities of metal fueled large fast reactors in case of accidents are discussed.

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key words: calculation methods; fast reactors; loss of flow; plutonium; reactor safety; risk assessment; sodium cooled reactors; temperature dependence; transient overpower accidents
Reference:
Technical committee meeting on methods and codes for calculations of thermohydraulic parameters for fuel, absorber pins and assemblies of LMFR's with traditional and burner cores. Obninsk (Russian Federation) 27-31 Jul 1998
International Atomic Energy Agency, Vienna (Austria)
IAEA-TECDOC--1157, pp:150-162