Fast Reactors and Accelerator Driven Systems Knowledge Base

Conference Article: Improvement of the performances of the ''poisoned'' CAPRA core by use of 11B4C

Gastaldo, G. (FRAMATOME Direction NOVATOME, Lyon (France)); Vambenepe, G. (Electricite de France SEPTEM, Cedex (France)); Garnier, J.C. (CEA Centre d'Etudes de Cadarache, 13 - Saint-Paul-lez-Durance (France))

Abstract

Two approaches have been considered in France by the CAPRA team to optimise a fast reactor for plutonium (or minor actinide) burning : the “dilution” and “poisoning” options /l/. At present, “dilution” is the preferred design as it allows better core safety parameters (mainly the Doppler constant). This paper shows a route, based on the use of a moderator material, 11B4C, to improve the core safety parameters (Doppler constant and sodium void reactivity worth) of the CAPRA B4C poisoned core. The aim is to obtain a convincing alternative to the “dilution” option. The introduction of the moderator inside the fuel bundle of the CAPRA B& poisoned core allows to strongly increase the Doppler constant (+ 62 %) and to reduce the sodium void reactivity worth (- 23 %). The “poisoned” CAPRA core with “B4C has similar plutonium burning performances and better core safety parameters than the “dilution” option. Its main advantages are linked to the larger diameter fuel pins: increased fuel lifetime and “standard” fuel bundle (397 pins instead of 469).

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key words: actinide burner reactors; fast reactors; lifetime; moderators; optimization; plutonium; poisoning; reactor cores; safety
Reference:
Technical committee meeting on absorber materials, control rods and designs of backup reactivity shutdown systems for breakeven cores and burner cores for reducing plutonium stockpiles. Obninsk (Russian Federation). 3-7 Jul 1995
International Atomic Energy Agency, Vienna (Austria)
IAEA-TECDOC--884, pp:185-190