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 ...

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*; *; *; *

PNC TJ1222 98-010, 15 Pages, 1998/02

PNC-TJ1222-98-010.pdf:0.38MB

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Imai, Hisashi*; Amemiya, Kiyoshi*; Nishida, Kaoru*; Lin, Weiren*; *; Senna, Shigeki*

PNC TJ1449 96-005, 76 Pages, 1996/03

PNC-TJ1449-96-005.pdf:2.36MB

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PNC TJ1449 95-005, 252 Pages, 1995/03

PNC-TJ1449-95-005.pdf:10.56MB

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