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Title: Mixing requirements for the limiting fuel-coolant interactions in liquid metal fast breeder reactors

Technical Report ·
DOI:https://doi.org/10.2172/7225054· OSTI ID:7225054

An estimation of the mixing requirements for the limiting fuel-coolant interactions in two specific liquid metal cooled fast reactors, the Fast Flux Test Facility (FFTF) and the Clinch River Breeder Reactor (CRBR), has been undertaken. The mixing requirements were represented in terms of the limiting mixing time constants. These constants were determined with the Argonne parametric FCI Computer Model for a range of core involvements. Specifically, fuel masses used ranged from as low as one-seventh of the core to a full core involvement. In general, conservative values for additional FCI input parameters were assumed such that the results would be conservative. With the results in hand, several mechanisms were investigated to determine what limiting effects they could have on the mixing rates of the fuel and coolant during an FCI. The energy requirements for mixing were investigated. The results, however, provided no limiting effects. A solidification limited fragmentation model was also investigated. Although this model provided no absolute limiting effects, it did show that fuel particle sizes of a certain size could indeed limit the fuel-coolant mixing rates. Additionally, the limiting effects were found to be much less significant for UC fuel. The third mechanism that was investigated concerned the limiting effects of the finite fuel release rates as a result of TOP accidents in the FFTF. Equivalent mixing time constants based on the fuel release rates were shown to be greater than the limiting values. Thus, this mechanism was shown to be limiting for the particular accident sequence investigated.

Research Organization:
Massachusetts Inst. of Tech., Cambridge (USA). Dept. of Nuclear Engineering
Sponsoring Organization:
US Energy Research and Development Administration (ERDA)
DOE Contract Number:
EY-76-S-02-2781
OSTI ID:
7225054
Report Number(s):
COO-2781-8TR; TRN: 77-009150
Country of Publication:
United States
Language:
English