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JNC TN4400 99-002, 192 Pages, 1999/03
The tritium transport analysis code, TTT, has been validated using data from the low power test of Monju, and then its behaviour at along term full power operation of Monju in future has been estimated, when the estimated transport and distribution of tritium in the reactor system has been also compared with the result in Joyo and Phenix, which had been already experienced long term operations. The TTT code had been develpped using the tiritium and hydrogen transport model proposed by R. Kumar, ANL, and had been applied to the evaluation in Monju design work. After then, futhermore, the code has been improved using the data from long term operation of Joyo with MK-II core, and in this work the code has been validated for the first time for Monju data. The results from this work are as follows; (1)Comparison of the best fitted tritium source rates from cores in Joyo, Phenix and Monju makes an estimation of the major source from control rods, (2)The calculated tritium concentration in each medium for cooling and its change is a reasonable agreement to the measured, C/E=1.1, (3)The cover gas transport model cosidering isotopic exchange of H and H
can reproduce reasonably the measured concentration distirbution of tritium in sodium and cover gas, (4)The tritium concentration in secondary sodium of Monju was about l/50 times as much as the primary one, which shows the acceraration effect on cold tarapping of tritium due to coprecipitation with permeated hydrogen through Evaporater (EV) heat conduction tube walls. The tritium cold trapping efficiency was estimated to be 1 for coprecipitation with hydrogen and 0.3 for isotopic exchange, respectively, (5)Tritium transport and distribution for along term full power operation of Monju in future was estimated, which could involve a excess factor to 4 at the maximum. The tritium concentration in sodium and Steam Generator (SG) water will be substantially saturated after somthing like 10 years full power operation, ...
Seno, Muneaki*; Ito, Kenji*; Ambo, Noriaki*; Fukaya, Masaaki*
PNC TJ1561 96-002, 54 Pages, 1996/02
None
Shirai, Nobutoshi; Sudo, Toshiyuki
PNC TN8460 95-001, 92 Pages, 1995/09
no abstracts in English
PNC TN9410 94-182, 29 Pages, 1994/06
A three-dimensional temperature fluctuation analysis was carried out using a general-purpose multi-dimensional thermohydraulics direct numerical simulation code DINUS-3 for parallel impinging jet experiments in sodium and water simulating thermal striping phenomena. The code utilized a third-order upwind scheme and an adaptive control system based on the Fuzzy theory to control time step sizes. The calculated results in both the cases showed evident differences mainly attributed to fluid properties such as heat conductivity, molecular viscosity, etc.. From the analysis, the following conclusions were obtained. (1)The amount of the temperature fluctuation damping by fluid mixing in sodium flow shows approximately two times larger than in water flow. While the damping amounts due to the laminar sub-layer in sodium flow is approximately 1/3 of that in water flow, (2)The variance of the probabilily density function for the calculated sodium temperature fluctuations is two times of the calculated water temperature fluctuations, and (3)The histogram of the normalized amplitude for calculated water temperature fluctuations can be fitted by a Layleigh distribution. By contrast, in the sodium case, the profile is very much like a exponential distribution. The results obtained in this work are very encouraging; the DINUS-3 code is one of the efficient measures to evaluate thermal striping phenomena in sodium, a low Prandtl number fluid, when one wishes to perform thermal striping evaluation in Liquid Metal Fast Breeder Reactors.
Yanagisawa, Ichiro*; Fusaeda, Shigeki*; Uzawa, Masayuki*; Kasai, Masao*; Ishihara, Yoshinao*; Ikeda, Yasuhiro*; Ezaki, Masahiro*
PNC TJ1214 94-007, 92 Pages, 1994/03
no abstracts in English
Yanagisawa, Ichiro*; Fusaeda, Shigeki*; Uzawa, Masayuki*; Kasai, Masao*; Ishihara, Yoshinao*; Ikeda, Yasuhiro*; Ezaki, Masahiro*
PNC TJ1214 94-006, 542 Pages, 1994/03
None
; Yamaguchi, Akira
PNC TN9410 93-213, 28 Pages, 1993/10
Loop-version of Super System Code (SSC-L) has been applied to the analysis of the secondary loop natural circulation test (heated up by the pumps: 4.3MWt) in Monju. The purposes of this study are to validate the computer program and to point out the additional plant data necessary for the analysis of the proposed tests with better accuracy. From the test results, generated heat in the pumps is 4.3 MWt while the removed heat at ACS is 3.4 MWt in the initial steady state. The difference is caused by heat losses from the heat transport system and it is taken into account in the SSC model. The tansient thermohydraulic performance in the secondary heat tansport system simulated using SSC-L is in agreement with the test data. Hence, the pressure loss model in SSC-L is validated and the code is applicable to the natural circulation conditions. Validation of other component models in SSC-L is in progress using Monju data towards a whole plant natural circulation test.
PNC TN9410 92-105, 65 Pages, 1992/04
A thermal striping phenomenon characterized by a random temperature fluctuation occurs in the region immediately above the FBR core due to the temperature difference of the core outlet coolant between subassemblies. In this study, a direct numerical simulation code DINUS-3(Direct NUmerical Simulation using 3rd order upwind scheme) has been developed based on the third order upwind scheme and investigated applicability of the DINUS-3 code to temperature fluctuation analysis. From the analysis of von Karman vortex streak behind a rectangular obstacle, the following results have been obtained: (1)Change of the vortex frequency (the strouhal number St) with increase of the Reynolds number Re can be estimated by the DINUS-3 code. (2)A stationary random turbulence fluctuation including a buffer region between the transition and the turbulent regions can be predicted using the DINUS-3 code. And the followings became clear after the analysis of a nonisothermal parallel jet experiment using water. (1)A temperature fluctuation phenomenon including complicated frequency components can be simulated well using the DINUS-3 code. (2)Calculated dominant frequency has shown good agreement with the experiment. From the analysis, it is concluded that the DINUS-3 code based on the third order upwind sheme has a sufficiently high potential in providing good interpretation of experimental results related to the temperature fluctuation phenomena such as thermal striping.
*; *
PNC TN9410 87-115, 101 Pages, 1987/08
To enhance the degree of analytical accuracy of a large leak sodium-water reaction in an LMFBR steam generator, the Long-Term Sodium-Water Reaction Thermohydraulic Analysis Code, SWAC13E, was modified and validated using experimental results. In the present study, besides the refinement of the two-phase flow model utilized in the code, a relative velocity and a heat transfer equation corresponding to each flow regime were newly provided. Following the modification, the calculational results were compared with the data of SWAT-3 Runs4, 5, 6, and 7. As the results of the modification, over-conservatism of fluid temperatures existing in the conventional model was reduced to a proper degree and the calculational results of temperatures and pressures agreed well with the experimental data. The prediction of a sodium mass expelled to the reaction products tank was improved, but it has still a certain degree of conservatism. This validation study revealed that SWAC13E.REG2 could replace the quasi-static pressure calculation module of SWACS, which had been used for the large leak analysis since the Construction Permission of the Prototype FBR, Monju.
Hiroi, Hiroshi*; Miyake, Osamu; *
PNC TN941 82-37, 170 Pages, 1982/02
Blowdown tests of high temperature and pressure water from a long pipe were carried out to validate the computer code SWAC-11 which is used for the calculation of the water leak rate from a failed heat transfer tube in an LMFBR's SG. The steady leak rate, and transients of pressure and thrust force of the pipe were measured. Especially, the short term transient of thrust force can be obtained by a new measuring method using the spring-mass model. These data were compared with calculation results of SWAC-11. As for steady data, the Moody's model of the critical flow and the effect of the two-phase multiplier were studied. Major conclusions are as follows: (1)The calculation results of SWAC-11 almost agreed with the steady data. But in detail, SWAC-11 inclined to predict 10 
15% less than experimental data of water leak rate and thrust force in the case of high pressure saturated water. This discrepancy will be reduced by introducing the Thom's correlation as the two-phase multiplier. (2)The calculation results of SWAC-11 also agreed with the experimental data after 5 msec since the blowdown was initiated. (3)The flow model of SWAC-11 can be applied to the blowdown of the subcooled water. (4)The thrust force (F) immediately after the blowdown is the sum of the wave force and the blowdown force. The relation of F, the initial pressure P
, and cross section S can be given by the expression, F/S
P=1.36. (5)Compared with calculation results in detail, the profiles of experimental data were found to be more complicated. This tendency was observed markedly in the case of the subcooled water blowdown. (6)Test results of superheated steam blowdown agreed with SWAC-11 predictions as for unsteady data as well as steady data.
