FIX-II/3061, BWR FIX-II Pump Trip Experiment 3061, Large Split Break

1 - Description of test facility: The FIX-II facility is a volume scaled 1:777 representation of a Swedish BWR with external pumps. The pressure vessel contains a 36 rod full length bundle and a spray condenser at the top to allow steady state operation. The downcomer, bypass channels and guide tube volumes are represented by external piping. The intact loop represents three of the four external reactor loops. The broken loop is constructed such that both guillotine breaks and split breaks may be simulated. The facility is equipped with ADS-simulation, but no ECCS injection are included. The FIX-II loop is also suited to investigate response of pump trips and MSIV closures in internal pump reactors. 2 - Description of test: Test No. 3061 is a simulated large split break. The break area was equal to the scaled down are of one of the four recirculation pipes in the reactor (100 %). The initial power should be equivalent to the average bundle power of the reactor and became here 2.51 MW, i.e. slightly higher