Attached are our recent MELCOR results for the Fukushima Daiichi Unit 4 spent fuel pool. These results show that there are no core concrete interactions, because the low decay power of the spent fuel results in temperatures below the ablation temperature of concrete.
I just spoke with Naval Reactors (NR), KAPL, and Bettis via their bridge line. NR is requesting the following:
1) a written position from the NRC by morning whether we believe fuel debris is likely to eat through the concrete floor of the spent fuel pool and fall into the next lower floor of the reactor building
2) our MELCOR spent fuel pool input deck for Fukushima Daiichi Unit 4 and our results of calculations with this model
3) the reports we produced over the last several years on analysis of severe spent fuel pool accidents.
Pages From C143073-02B –13 Fuku-4 Fuel Pool – MELCOR Results