Analysis of a BWR turbine trip experiment by entire plant simulation with spatial kinetics

Asahi, Yoshiro; Suzudo, Tomoaki; Ishikawa, Nobuyuki; Nakatsuka, Toru

Nuclear Science and Engineering, 152(2), p.219 - 235, 2006/02

https://doi.org/10.13182/NSE06-A2577

An analysis of a BWR turbine trip experiment was performed with the THYDE-NEU code. The plant was treated as a closed coolant system whose pressure ranges to the atmospheric pressure. To simulate an entire plant, it was found necessary to have the moisture separator model and to account for reversible pressure drops at a junction with an area change. A spatial kinetics model without a notion of reactivity was applied. It was confirmed that THYDE-NEU can perform a coupled neutronic and thermal-hydraulic null transient at the hot full power. Among factors influencing spatial kinetics in the turbine trip were the temporal behavior of the bypass valve opening, the thermal non-equilibrium model and the manner in which to express the coolant density used in the table look-up of cross sections. By adjusting these factors, it was found possible to generate the scram signal when the core averaged LPRM output reached the prescribed value. The other calculated results also were found satisfactorily in agreement with the experimental results.