SIEX: a correlated code for the prediction of Liquid Metal Fast Breeder Reactor (LMFBR) fuel thermal performance

Abstract

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Fuel Pin and Assembly Design

“…[7]) 3), lies below the columnar temperature by 58 K at 1 h, and extends to 78 K less at 10,000 h. Whereas the above formulation contains an explicit time dependence for the restructuring temperatures, other experience developed in the formulation of Ref. [8] suggests that in-pile mixed oxide fuel data can be fit quite adequately by using the following simplified forms, which are time-independent:…”

High Burnup Effects Program A State-of-the-Technology Assessment

“…The difference between the two fuel types increases with decreasing temperature and thereby indicates that caution should be exercised when comparing low temperature gas release from U0 2 and mixedoxide fuels. Dutt and Baker (1975) This paper presented a fission gas release correlation based on results obtained from release measurements made on 77 fuel pins irradiated in the EBR-II reactor. The mixed-oxide fuels had small diameters, approximately 5 mm, and were irradiated at high fission rates, 3 to 7 x 10 13 fissions/cm 3 -sec.…”

“…The NRC recently developed a correction factor to account for the apparent burnup enhancement and has required that this factor be included in calculations of fission gas release for burnups above 20 GWd/MTM. The correction factor is based on the Dutt and Baker ( 1975) correlation which, as discussed previously, indicates a strong burnup dependence.…”

“…The data of Zimmermann (1975,78) and the Dutt and Baker (1975) correlation provide the most graphic evidence for enhanced fission gas release at high burnup. However, as shown in Figure 1, there are large differences in the apparent burnup dependences which are most likely associated with the particular parameters chosen to develop the correlation.…”

“…For example, a higher release fraction is expected from a fuel rod whose temperature continuously decreased with burnup compared with one irradiated continuously at the same end-of-life temperature. The temperature or power histories were not given for any of the data reported by Zimmerman (1975Zimmerman ( , 1978 or Dutt and Baker (1975) and thereby precludes any evaluation of the effects of power histories or identification of other temperature related parameters that could provide a more meaningful correlation.…”