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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 TN9400 2000-092, 247 Pages, 2000/08
JNC-TN9400-2000-092.pdf:20.29MB
Small-scale sodium pool combustion tests Run-F7-3 and Run-F8-1 were performed to investigate the corrosion of floor liner under high moisture condition. ln the both tests, which were performed using the 3m
FRAT-1 vessel at the SAPFIRE facility, the sodium of 507deg-C was leaked on the carbon steel catch pan about for 25 minutes with the flow rate of around 25 kg/h. The air in the vessel was ventilated with the flow rate of 5m/min containing the moisture of 25000-28000 vol.ppm. The duration of combustion was different in two tests by changing the starting time of argon gas injection into the vessel. As the results of post-test analysis such as observation of catch pan surface and chemical analysis of the deposits, it was confirmed that 'Na-Fe double oxidization type corrosion' was dominant in the both tests and that the catch pan and deposits were not under the condition leading to the occurrence of 'molten salt type corrosion.'
; Takai, Toshihide; ; ; Miyake, Osamu; Tanabe, Hiromi
JNC TN9400 2000-090, 413 Pages, 2000/08
JNC-TN9400-2000-090.pdf:16.61MB
As a part of the work for investigating the sodium leak accident which occurred in the Monju reactor (hereinafter referred to as Monju), sodium fire test-II was carried out using, the SOLFA-1 (Sodium Leak, Fire and Aerosol) facility at OEC/PNC. ln the test, the piping, ventilation duct, grating and floor liner were all full-sized and arranged in a rectangular concrete cell in the same manner as in Monju. The main objectives of the test were to confirm the leak and burning behavior of sodium from the damaged thermometer, and the effects of the sodium fire on the integrity of the surrounding structure. The main conclusions obtajned from the test are shown below: (1)Burning Behavior of Leaked Sodium : lmages taken with a cameras in the test reveal that in the early stages of the sodium leak, the sodium dropped down out of the flexible tube in drips. (2)Damage to the ventilation Duct and Grating: The temperature of the ventilation duct's inner surface fluctuated between approximately 600
C and 700C. The temperature of the grating began rising at the outset of the test, then fluctuated betvveen roughly 600C and 900C. The maximum temperature was about 1000C. After the test, damage to the ventilation duct and the grating was found. Damage to the duct was greater than that at Monju. (3)Effects on the Floor Liner : The temperature of the floor liner under the leak point exceed l,000C at 3 hours and 20 minutes into the test. A post test inspection of the liner revealed five holes in an area about 1m 
1m square under the leak point. There was also a decrease of the liner thickness on the north and west side of the leak point. (4)Effects on Concrete: The post test inspection revealed no surface damage on either the concrete side walls or the ceiling. However, the floor concrete was eroded to a maximum depth 8 cm due to a sodium-concrete reaction. The compressive strength of the ...
Kawada, Koji; ; Ohno, Shuji; ; Miyake, Osamu; Tanabe, Hiromi
JNC TN9400 2000-089, 258 Pages, 2000/08
JNC-TN9400-2000-089.pdf:12.26MB
As a part of the work for investigating the sodium leak accident which occurred in the Monju reactor (hereinafter referred to as Monju) on December 8, 1995, threetests, (1)a sodium leaktest, (2)a sodium leak and fire test-I, and(3)a sodium leak and fire test-II, were carried out at OEC/PNC, The main objectives of these tests were to confirm the leak and burning behavior of sodium from the damaged thermometer, and the effects of the sodium fire on the integrity of the surrounding structure. This report describes the results of the sodium fire test-I carried out as a preliminary test. The test was performed usjng the SOLFA-2 (Sodium Leak, Fire and Aerosol) facility on April 8, 1996. In this test, sodium heated to 480C was leaked for approximately l.5 hours from a leak simulating apparatus and caused to drop onto a ventilation duct and a grating with the same dimensions and layout as those in Monju. The main conclusions obtained from the test are shown below: (1)Observation from video cameras in the test revealed that jn the early stages of the sodium leak, sodium dripped out of the flexible tube of the thermometer. This dripping and burning expanded in range as the sodium splashed on the duct. (2)No damage to the duct itself was detected. However, the aluminum louver frame of the ventilation duct's lower inlet was damaged. lts machine screws came off, leaving half of the grill (on the grating side) detached. (3)NO large hole, like the one seen at Monju, was found when the grating was removed from the testing system for inspection, although the area centered on the point were the sodium dripped was damaged in a way indicating the first stages of grating failure. The 5mm square lattice was corroded through in some parts, and numerous blades (originally 3.2 mm thick) had become sharpened like the blade of a knife. (4)The burning pan underside thermocouple near the leak point measured 700C in within approximately 10 minutes, and for the next ...
Hamada, Hirotsugu;
JNC TN9400 2000-091, 69 Pages, 2000/07
JNC-TN9400-2000-091.pdf:1.42MB
The Tube Rupture Evaluation Code (TRUE) was developed to analytically evaluate the overheating and the integrity of heat transfer tubes under an intermediate water leak in an FBR Steam Generator. TRUE was programed based on the structural and temperature calculation models. To validate the code performance, an experimental analysis was carried out by using the Tube Rupture Simulation Test (TRUST-2) data.TRUST-2 simulated overheating rupture of the tubes made of the 2.25Cr-1Mo steel by the nitrogen gas pressurization and the quick induction heating. The results of validation analysis are as follows: (1)lt was confirmed that the code conservatively evaluated the occurrence of overheating rupture and its failure time (10 - 50% earlier) in all test cases. (2)ln the test case of quick heating after the gas pressurization, the failure time with conservatism of 10% and the failure temperature with conservatism of 100C were obtained between the test and analysis. (3)ln the test case of creep rupture, it reveals that the time factor of 1.5
2 gives a good agreement and that of 3.0 gives an enough margin between the test and analysis.
Nakagiri, Toshio
JNC TN9400 2000-030, 93 Pages, 2000/02
JNC-TN9400-2000-030.pdf:2.21MB
Evaluation of water transport behavior in Sodium Fire -II (Run-D4) was performed. Results of other experiments performed in Oarai-Engineering Center were considered in the evaluation, and the results of the evaluation were compared with the calculated results of ASSCOPS code. The main conclusions are described below. (1)lt was estimated that aerosol hydrates were not formed in the test cell in the experiment, because of high gas temperatures (200C300C), but water vapor absorption by the formation of aerosol hydrates and water vapor condensation were occurred in humidity measure line, because of low gas temperature (20C 40C). Therefore, it was considered appropriate that measured water vapor concentration in the humidity measure line was different from the real concentration in the test cell. (2)Water vapor concentration in the test cell was assumed to be about 35,000 ppm during sodium leak, and reached to about 70,000 ppm because of water release from heated concrete (over 100C) walls after 190 min from sodium leak started. The assumed value of about 35,000 ppm during sodium leak almost agree with assumed value from the quantity of aerosol in the humidity measure line, but no support for the value of about 70,000 ppm after 190 min could be found. Therefore, water release rate from heated concrete wans can change with their temperature history.