Internal Fuel Motion in Annular Fuel for 50 Cents/S and 3 Cents/S Transient Overpower Accidents.

摘要

In this paper, the whole-core reactivity consequences of internal fuel motion in annular fuel during hypothetical 50 cents/s and 3 cents/s transient overpower (TOP) accidents are compared using results calculated by the MELT-IIIB/FUMO-E code to determine the range of effectiveness of this inherent safety shutdown mechanism. It has been postulated that the use of annular fuel provides an inherent safety shutdown mechanism during hypothetical LMFBR accidents by providing a pathway for molten fuel to be ejected from the active core region to the fission gas plenum. To verify this concept, the PINEX-2 and PINEX-3 experiments were performed in the TREAT reactor using annular fuel pins irradiated in the General Electric Test Reactor (GETR). The FUMO-E computer code was developed to predict the hydrodynamic two-phase (molten fuel and fission gas/fuel vapor) motion in annular fuel during hypothetical LMFBR accidents, was validated against the PINEX-2 and PINEX-3 experiments, and has been incorporated into the MELT-IIIB whole-core accident analysis code. The results are presented for an intermediate ramp rate case (50 cents/s) and the 3 cents/s case, both with an improved fission gas release model. (ERA citation 08:014937)