Distribution of actinide elements among various environmental factors (II)

Kudo, Akira*; Fujikawa, Yoko*

JNC TJ8400 2000-010, 67 Pages, 2000/02

JNC-TJ8400-2000-010.pdf:2.17MB

The first and second environmental releases of man-made Pu came from nuclear explosions at Alamagordo and Nagasaki in 1945. The release at Nagasaki was more serious than at Alamagordo, because it happened in an area with a high population density. Unfissioned Pu and various fission products have been interacting here with various environmental materials (soils, sediments, and plants) under wet and temperature conditions for more than 45 years. To assess the environmental mobility of Pu, the distributions of radionuclides from this release were investigated at Nishiyama where heavy black rain containing unfissioned plutonium and fission products fell 30 minutes after the nuclear explosion. The vertical distributions of Cs and Pu were determined in unsaturated soil cores up to 450cm deep. Most radionuclides were found in the soil column 30cm from the ground surface. However, Pu were detected in the groundwater as well below a depth of 200cm. No Cs was found below 40cm from the ground surface or in groundwater. These observations reveal that about 3% of the total Pu have been migrating in the soil at a faster rate than the remaining Pu. Sharp peak of Cs and Pu, indicating heavy deposition from the Nagasaki local fallout of 1945, were found in sediment cores collected from the Nishiyama reservoir. Pu peaks were unexpectedly discovered in pre-1945 sediment core sections. NO Cs was found. By contrast to the distribution in sediment cores, Cs in tree rings had spread by diffusion from the bark to the center of the tree without holding a fallout deposition record. Most of the Pu was distributed in the tree rings following a similar deposition record to that found in sediment cores. Furthermore, a very small amount of Pu (about 1%) was found unexpectedly in pre-1945 tree rings. The only reasonable ...

Tritium behavior in fusion reactor facilities and the environment, 7; Tritium behavior in bodies, 7.6, Cooles to estimate environmental tritium transfer and dose, 7.6.2, Environmental tritium transfer and dose estimation code using personal computer

Amano, Hikaru

Purazuma, Kaku Yugo Gakkai-Shi, 73(12), p.1360 - 1361, 1997/12

https://ci.nii.ac.jp/naid/110003826820

no abstracts in English

An Analysis of the secondary loop natural circulation test in Monju using SSC-L

; Yamaguchi, Akira

PNC TN9410 93-213, 28 Pages, 1993/10

PNC-TN9410-93-213.pdf:0.71MB

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.

Validation on a water leak calculation module of SWACS by high temperature and pressure water blowdown tests; Report No.2 : Study of water leak rate from a failed heat transfer tube in an LMFBR's SG

Hiroi, Hiroshi*; Miyake, Osamu; *

PNC TN941 82-37, 170 Pages, 1982/02

PNC-TN941-82-37.pdf:3.0MB

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/SP=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.