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Takata, Takashi; Yamaguchi, Akira
JNC TN9400 2000-065, 152 Pages, 2000/06
JNC-TN9400-2000-065.pdf:6.26MBJNC-TN9400-2000-065(errata).pdf:0.12MB
ln the liquid metal fast reactor (LMFR) using liquid sodium as a coolant, it is important to evaluate the effect of the sodium combustion on the structure, etc. Most of the previous analytical works are based on a zone model, in which the principal variables are treated as volume-average quantities. Therefore spatial distribution of gas and structure temperatures, chemical species concentration are neglected. Therefore, a multi-dimensional sodium combustion analysis code AQUA-SF (Advanced simulation using Quadratic Upstream differencing Algorithm - Sodium Fire version) has been developed for the purpose of analyzing the sodium combustion phenomenon considering the multi-dimensional effect. This code is based on a multi-dimensional thermal hydraulics code AQUA that employs SIMPLEST-ANL method. Sodium combustion models are coupled with AQUA; one is a liquid droplet model for spray combustion, and the other is a flame sheet model for pool combustion. A gas radiation model is added for radiation heat transfer. Some other models necessary for the sodium combustion analysis, such as a chemical species transfer, a compressibility, are also added. ln AQUA-SF code, bounded QUICK method in space scheme and bounded three-point implicit method in time scheme are implemented. Verification analyses of sodium combustion tests shown in the following have been carried out. (1)pool combustion test (RUN-D1) (2)spray combustion test (RUN-E1) (3)sodium leakage combustion test (Sodium Fire Test-II) (4)smaII-scale leakage combustion test (RUN,F7-1) ln each verification analysis, good agreements are obtained and the validity of AQUA-SF code is confirmed.
Ohno, Shuji; Matsuki, Takuo*; ; Miyake, Osamu
JNC TN9520 2000-001, 196 Pages, 2000/01
JNC-TN9520-2000-001.pdf:5.13MB
ASSCOPS (Analysis of Simultaneous Sodium Combustion in Pool and Spray) has been developed for analyses of thermal consequences of sodium leak and fire accidents in LMFBRs. This report presents a description of the computational models, input and output data as the user's manual of ASSCOPS version 2.1. ASSCOPS is an integrated computational code based on the sodium pool fire code SOFIRE II developed by the Atomics International Division of Rockwell International, and on the sodium spray fire code SPRAY developed by the Hanford Engineering Development Laboratory in the U.S. The users of ASSCOPS need to specify the sodium leak conditions (leak flow rate and temperature, etc.), the cell geometries (cell volume, surface area and thickness of structures, etc.), and the atmospheric initial conditions such as gas temperature, pressure, and composition. ASSCOPS calculates the time histories of atmospheric temperature, pressure and of structural temperature.
Morii, Tadashi*; Himeno, Yoshiaki
PNC TN9410 86-066, 27 Pages, 1986/06
Sodium fire analysis has been performed for a large FBR to evaluate pressure and temperature transients and mass of burned sodium in case of a primary sodium leak accident. The major analytical conditions are as follows: [Position of sodium leak : Hot leg of primary coolant system] [Cross-sectional area of a leak hole : 1 cm
] [Concrete cooling system : operated (just before failure), shut down (after sodium leak)] The most representative results gained through the present study are as follows: [Maximum Gas Pressure : 0.029 kg/cm2 -g (0.5 hr after a leak)] [Total Mass of Burned Sodium : 1.5 ton (3% of total leak sodium)] [Maximum Concrete Temperature (beneath sodium pool) : 140
C (100 hr after a leak) These results indicate that a concrete cooling system to present abnormal temperature rise that may occure due to heat transfer from the hot primary coolant system was shown to be effective even in the accident conditions. However, further study will be needed to evaluate water release rate from the heated concrete.