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Ohno, Shuji; Matsuki, Takuo*
JNC TN9400 2000-106, 132 Pages, 2000/12
Sodium fire analyses were performed on 7 kinds of sodium leak tests using a computer code ASSCOPS which has been developed to evaluate thermal consequences of sodium leak accident in an FBR plant. By the comparison between the calculated and the test results of gas pressure, gas temperature, sodium catch pan temperature, wall temperature, and of oxygen concentration, it was confirmed that the ASSCOPS code and the parameters used in the analysis give valid or conservative results on thermal consequences of sodium leak and fire.
; Ohno, Shuji;
JNC TN2400 2000-006, 56 Pages, 2000/12
JNC-TN2400-2000-006.pdf:1.22MB
Sodium combustion analyses were performed using ASSCOPS version 2.1 in order to obtain background data for evaluating the validity of the mitigation system against secondary sodium leak of MONJU. The calculated results are summarized as follows. (1)Peak atmospheric pressure 
4.3 kPa[gage] (2)Peak floor liner temperature 870
C, Maximum thinning of liner 2.6mm (3)Peak hydrogen concentration <2% (4)Peak floor liner temperature in the spilt sodium storage eell 400C , Peak floor concrete temperature in the spilt sodium storage cell 140C.
; ; Ueno, Fumiyoshi; ; ; ;
JNC TN2400 2000-005, 103 Pages, 2000/12
JNC-TN2400-2000-005.pdf:3.98MB
Inelastic analyses of the floor liner subjected to thermal loading due to sodium leakage and combustion were carried out, considering thinning of the liner plate due to molten salt type corrosion. Because the inelastic strain obtained by the analyses stayed below the ductility limit of the material, mechanical integrity, i.e., there exist no through-wall crack on the floor liner, was confirmed. Partial structural model tests were conducted, with a band of local thinning of the liner plate. Displacements were controlled to give specimens much larger strains than those obtained by the inelastic analyses above. No through-wall crack was observed by these tests. Mechanical integrity of the floor liner was confirmed by these results of the inelastic analyses and the partial structural model tests.
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.
; Miyake, Osamu;
PNC TN9410 98-037, 81 Pages, 1998/04
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 (Na
O: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 ...
; ; Tanabe, Hiromi; Ohno, Shuji; Miyake, Osamu;
PNC TN9410 97-030, 93 Pages, 1997/04
A sodium fire analysis code, ASSCOPS(Analysis of Simultaneous Sodium Combustions in Pool and Spray) was developed coupling the computer codes of SPRAY-IIIM and SOFIRE-MIl to assess temperature-pressure transients resulting from sodium spray and pool combustions, simultaneously. The validation of ASSCOPS was conducted using the experimental results obtained from sodium spray fire experiments using 21 m
vessel and the accuracy of calculated results was discussed. The following results were obtained: (1)Study under inert gas atmosphere. The comparison between analysis and experiment with regard to the pressure and the temperature showed a good agreement. (2)Study under air atmosphere. The comparison between analysis and experiment with regard to the pressure and the temperature also showed a good agreement. (3)Effects of parameter used in evaluating the design of Monju. The peak pressure and temperature obtained by the analysis overestimates the experimental results. From these results, it was concluded that the development and validation of ASSCOPS indicate a improvement on the burning and the heat transfer models in SPRAY-IIIM.
; Matsuki, Takuo*; Hiroi, Hiroshi*; Himeno, Yoshiaki
PNC TN9410 88-092, 82 Pages, 1988/08
Post-test calculations of the large-scale sodium leak demonstration test, Run-D2, were performed using the ASSCOPS code in order to validate the applicability of the code to the evaluation of the fire suppression function of the PNC-type smothering tank. In the analysis, radiation coefficients between aerosols in the gas phase and structures and a pool surface in the smothering tank defined in the code were varied as parameter. The following three cases were calculated. (a)No aerosols suspending was assumed in the gas phase and thus, 1.0 was used as the coefficient between the structures and the pool surface. (b)The coefficient between the aerosols and the pool surface was 0.65, and that between structures and the aerosols was 0.73. (c)The coefficient between the aerosols and the pool surface was the same as case (b) and 0.5 was used as that between structures and the aerosols. The comparison between analysis and experiment with regard to the temperature of the various parts showed that the agreement was within +30% and -20%. From these results, it was concluded that the code was available for the evaluation of the fire suppression function of the smothering tank.
Miyake, Osamu; Yamazaki, Hiroshi*; *; Himeno, Yoshiaki; Miyaguchi, Kimihide
PNC TN941 85-131, 53 Pages, 1985/08
For the analysis of sodium pool fire accidents in the LMFBR safety design, the computer codes SOFIRE-MII and ASSCOPS (the latter evaluate the pool-spray combined fires) have been utilized. In regard to the combustion phenomena of pool fire, better understanding has been obtained by experiments since the time of development of above mentioned codes. On the other hand, for the purpose of rationalization of the present LMFBR plants, the detailed analysis code is supposed to be required which can evaluate the sodium fires and their thermal effects more accurately and can remove existing conservatism of the present codes. Therefore, considering the requirement of the current status and trends, a new sodium pool fire model (SPM) has been accomplished mainly aiming at the evaluation of sodium fires under the air-filled secondary system condition. To model the actual phenomena precisely as possible, SPM takes account of the combustion flame above the pool surface, and the combustion heat and the heat transports to ambient and to the surrounding structures are estimated. To verify SPM, the comparisons of calculated results with experimental data obtained by the U.S. HEDL's CSTF and the German KfK's FAUNA facilities are presented. The comparisons with SOFIRE-II and SOFIRE-II are also discussed. Results show that the SPM predictions give reasonable agreement or somewhat overestimation, though, the pool temperature predictions are greatly improved in comparison with those of SOFIREs.