Validation of sodium combustion computer code ASSCOPS version 2.0; Pool combustion

not registered ; Miyake, Osamu; not registered

The sodium combustion computer code ASSCOPS has been developed for analyses of thermal consequences (i.e.pressure and temperature time histories) of sodium leak accidents in FBR plants. Version 2.0 of ASSCOPS, that is used in the study of this report, includes improvements and additional models over the previous versions. This report describes the validation of ASSCOPS (version 2.0) by using sodium pool combustion tests data obtained from FAUNA (F5, F6) at KfK, Germany, and SOLFA-1 (Run-D1) at PNC. The validation includes comparisons of calculation results of ASSCOPS (Version 2.0) with experimental data, and with calculation results of the previous version of ASSCOPS (Version 1.1). Furthermore, the effects of reaction products ratio (NaO:NaO), initial humidity in the atomsphere, and radiation coefficient from the sodium pool to the gas were studied. The following results have been obtained from the study. (1)The calculation results agree well with the experimental data of the gas, sodium, and structure temperatures, and gas pressures. (2)The reaction products ratio (NaO:NaO) is one of the most important parameters for sodium combustion evaluation. It affects the pressure and temperature due to the difference of the reaction heat. Selection of proper value for this parameter results in the best estimate of the pressure, temperature and oxygen concentration. The ratio of NaO: NaO = 60: 40 is adequate for the purpose of conservative evaluation. (The analysis under the oxygen concentration below 10 % assumes NaO: NaO = 100: 0) (3)Initial humidity concentration in the air has been more little affect to the pressure and temperature than the reaction products ratio or the radiation coefficient of pool surface affect. (4)The radiation coefficient of pool surface was surveyed around the value obtained by conventional evaluation. The results shows that suppression of radiative heat transfer ...