Analytical evaluation of the rim effect in LWR (U,Gd)O[sub 2] fuel

Conference · Wed Jan 01 04:00:00 EST 1992 · Transactions of the American Nuclear Society; (United States)

OSTI ID:6672956

Kameyama, T; Matsumura, T; Kinoshita, M ^[1]

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1. Central Research Institute of the Electric Power Industry, Tokyo (Japan)

It has been reported that the peripheral region of high-burnup fuel has a different microstructure of subdivided grains (called rim structure) from the as-fabricated one. More plutonium is produced in the peripheral fuel region than in the central region due to [sup 238]U neutronic self-shielding; therefore, burnup is 2 to 3 times higher in the peripheral region than in the central region. This is the mechanism of neutronic rim effect. The rim effect accelerates the rim structure formation, which could contribute to increased fission gas release and thermal conductivity degradation. Gadolinia will be mixed in pressurized water reactor (PWR) fuel as well as boiling water reactor fuel to reduce initial power peaking in an extended burnup core. Gadolinia has a large neutron capture cross section and accordingly enhances the rim effect in (U,Gd)O[sub 2] fuel. This paper describes the results of rim effect analysis in (U,Gd)O[sub 2] fuel using a calculation code verified with postirradiation examination (PIE) data.

• OSTI ID: 6672956
• Report Number(s): CONF-921102--
• Conference Information: Journal Name: Transactions of the American Nuclear Society; (United States) Journal Volume: 66
• Country of Publication: United States
• Language: English

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