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; 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.
;
JNC TN9400 2000-020, 54 Pages, 1999/11
JNC-TN9400-2000-020.pdf:2.36MB
A Laser-induced breakdown spectroscopy Leak Detection technique (abbreviated LLD) of sodium is accomplished by plasmafying the sodium aerosol, and then selectively detecting the sodium specific optical spectrum. This method is potentially more reliable as a means of detecting of sodium small leakage. This report, describes test results of detection characteristics using sodium aerosol, carried out to verify the principle of LLD in addition to evaluating the response under various conditions. 0ur main objective is to examine the applicability of LLD for small sodium leakage. The main results are as follows; (1)We confirmed the principle of LLD, specifically detecting the sodium optical spectru.m. (2)The relation between LLD fluorescence intensity and sodium aerosol concentration is nearly proportional within a relatively Na concentration ranges 10
10
g/cm
. (3)The LLD signal appeared insensitive to the effect of sampling gas flow rate, oxygen concentration, and humidity in the examined range. ln fact, a high S/N ratio is obtained for small sodium leakage, and the reliability of the leakage detection is high, because LLD showed sensitive to sodium concentration. From these results and others discussed in this report, LLD appears to be an applicable technique in small leakage detection both in terms of response and reliabilily in the leakage phase.
Shimoyama, Kazuhito; Usami, Masayuki; Miyake, Osamu; ; ; Tanabe, Hiromi
PNC TN9450 97-007, 81 Pages, 1997/03
None
Kawabe, Ryuhei*; Himeno, Yoshiaki; Kawada, Koji*; Miyaguchi, Kimihide
PNC TN941 85-104, 17 Pages, 1985/06
Flow and combustion test of low temperature sodium (250C) on a simulated for liner has been conducted to give an answer to the possible flow blockage or flow plugging. The simulated floor liner used for this purpose was 2.4m in length and 1.2m in width having liner gradient of l/100. The bottom surface of the liner was well thermally insulated. In the test, 160kg of sodium was slowly spilled from a nozzle having a wide opening at flow rate of 1 
/sec for 200 sec. The nozzle was attached to the side of the liner. Flow pattern and combustion characteristics of sodium have been monitored during the test, and temperatures of the flowing sodium and a liner steel have also been measured. In the post-test examinations, distribution of residual sodium and sodium oxide on the floor liner as well as that in a drain pipe was determined. The results thus obtained were summarized as follows. (1)At beginning of the test, although the spilled sodium froze for a certain period of time due to its heat transfer to the liner, it remelted by taking heat from a successive flowing sodium at higher temperature. Therefore, on the liner sodium flowed continuously without being blocked its flow path. (2)Heat flux from sodium to the liner was less than 80kw/m
, while related heat transfer coefficient was 300 500w/mC. The latter value was almost the same to that obtained from the similar test with hot sodium (505C). (3)Post-test examination revealed that the distribution of residual sodium and sodium oxide on the floor liner was almost uniform with the average value of 1kg/m. No massive combustion products that may cause flow plugging was found in a sodium drain pipe.
Kawabe, Ryuhei*; Himeno, Yoshiaki; *; *; *
PNC TN941 84-124, 56 Pages, 1984/08
At Sodium Leak-Fire Basic Test Rig (SOFT-1), three tests were performed, which were : (1)Run-A1 : For the aim of understanding the sodium combustion phenomena, 180 sodium was burnt in an open pool, and temperature transients in sodium was measured and burning rate were determined. (2)Run-B1 : For the evaluation of efficiency of fire suppression board, burning sodium was covered by a slitted board and change in burning rate was observed and drain test was performed using 530 C sodium to confirm the function and integrity of draining pipe. (3)Run-B2 : In order to clarify the burning-hydraulic behavior of sodium on liner, 505C, 180 sodium was discharged onto 1.2m
2.4m steel plate with 1/100 gradient, and temperature transients and mass of residuum were measured. Following results were obtained. (i)When sodium was heated up to 400C and exposed to air, the sodium was ignited. (ii)The surface temperature reached 650 C, 7 min. after the ignition and the temperature was almost constant from that. (iii)Under a conservative condition where air flowed over the fire suppression board by forced convection, the sodium burning rate and the aerosol generating rate where pool surface were covered by fire suppression board (opening area 1%) was about 3 % and 5 % of those in open pool burning respectively. (iv)The maximum heat flux to the draining pipe wall reached 1.210
W/m. Any cracking, however, was not found on the draining pipe wall even by color check. (v)In the liner test Run-B2, on the liner there remained large amount of sodium oxide, which worked as wick, and the soaked sodium burned after sodium supplying finished, resulting liner temperature 643 C which was higher than the supplied sodium temperature. The amount of sodium oxide was 8.7kg/m on the liner after the test. (vi)The maximum temperature, flow velocity and burning rate of sodium on liner and maximum heat ...