Thermal group fuel temperature feedback in high-burnup fuel

Journal Article · Tue Dec 31 04:00:00 EST 1996 · Transactions of the American Nuclear Society

OSTI ID:426525

Kallfelz, J M; Paratte, J M ^[1]; Sengstag, T ^[2]

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1. Paul Scherrer Inst., Villigen (Switzerland)
2. Swiss Federal Inst. of Technology, Zuerich (Switzerland)

For certain reactivity insertion accidents, the fuel-temperature coefficient (FTC) determines the major component of the feedback reactivity, which limits the peak fuel enthalpy during the transient. In addition to the Doppler component from the resonance range, the FTC has a component due to the temperature dependence of the oxygen scattering in the fuel. Changes in the fuel temperature T{sub f} cause shifts in the thermal neutron spectrum and associated changes in the thermal-group cross sections. However, this and other sources of a thermal-group contribution to the FTC (TFTC) are sometimes ignored in transient-code cross-section libraries. While for fresh fuel this component is negative, with burnup, the TFTC becomes less negative and eventually has a positive value. The purpose of this paper is to discuss some aspects of the TFTC for high-burnup fuel, focusing on the influence of the scattering kernel for oxygen in UO{sub 2} used in the calculations.

• OSTI ID: 426525
• Report Number(s): CONF-961103--
• Journal Information: Transactions of the American Nuclear Society, Journal Name: Transactions of the American Nuclear Society Vol. 75; ISSN TANSAO; ISSN 0003-018X
• Country of Publication: United States
• Language: English

Related Subjects

22 GENERAL STUDIES OF NUCLEAR REACTORS
BURNUP
FEEDBACK
NUCLEAR FUELS
OXYGEN
REACTIVITY INSERTIONS
SCATTERING
TEMPERATURE COEFFICIENT