Improvement of the sodium-water chemical reaction analysis code SIMMER-SW(2) (report under the contract between JNC and Toshiba Corporation)

It is necessary for the evaluation of the design base flow rate of water leakage out of the steam generator heat transfer tubes to evaluate the possibility of a tube-failure propagation quantitatively, which needs development of the followings, (1) Blow down model of the steam generator heat transfer tube, (2) Rupture model at high temperature of the steam generator heat transfer tube, and (3) Sodium-water chemical reaction model to analyze the temperature distribution around a leakage point. In this study, development effort is focused on the item (3) that is most important to the evaluation of failure propagation. The FBR safety analysis code SIMMER-III is used as a reference to realize the analysis and is named SIMMER-SW. The followings were done in this work: Coding of the chemical reaction model, and verification of the model functions, Coding of the rod bundle pressure drop model, and verification of the model functions, Coding of the preprocessor to prepare the input for a rod bundle, Data production of the EOS (Equation-of-State) and TPP Thermophysical Properties), Investigation of the interaction between sodium and jet out of a leak hole, Modeling of the thermocouple, SWAT1/P06 test analysis, and SWAT3/Run19 test analysis. The following knowledge was obtained: The results of the SWAT1/P06 test analysis which can be done in two-dimension agree well with that of the experiment at least qualitatively, Thermocouple model is very useful in the analysis such that various kinds of components contact a thermocouple, The constant K in chemical reaction model is likely to be 0.01 < K < 0.1, and The results of the AWAT3/Run19 test analysis which should be done in three-dimensional do not agree with that of the experiment. (author)