2001 Fiscal Year Final Research Report Summary
EDUCATION OF ANALYTICAL METHOD FOR THE MIGRATION STUDY OF ENVIRONMENTAL PLUTONIUM
| Project/Area Number |
11450198
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| Research Category |
Grant-in-Aid for Scientific Research (B)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
Civil and environmental engineering
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| Research Institution | KYOTO UNIVERSITY |
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Principal Investigator |
KUDO Akira KYOTO UNIVERSITY, RESEARCH REACTOR INSTITUTE, PROFESSOR, 原子炉実験所, 教授 (00281113)
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| Co-Investigator(Kenkyū-buntansha) |
SASAKI Takayuki KYOTO UNIVERSITY, RESEARCH REACTOR INSTITUTE, RESEACH ASSOCIATE, 原子炉実験所, 助手 (60314291)
MATSUI Saburo KYOTO UNIVERSITY, FACULTY OF ENGINEERING, PROFESSOR, 工学研究科, 教授 (90092808)
SUGAWARA Masataka OSAKA SANGYO UNIVERSITY, PROFESSOR, 工学部, 教授 (60026119)
KUBOTA Takumi KYOTO UNIVERSITY, RESEARCH REACTOR INSTITUTE, RESEACH ASSOCIATE, 原子炉実験所, 助手 (90335240)
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| Project Period (FY) |
1999 – 2001
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| Keywords | PLUTONIUM / ENVIRONMENT / ANALYSIS / EDUCATION / PLUTHERMAL / TRAINING |
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| Research Abstract |
An artificial single dose contaminant was released at Nagasaki, Japan on August 9,1945 detonating Plutonium (10-15kg) atomic bomb. A portion, 1.2 kg of 239Pu was fissioned releasing 21 kt TNT energy along with various fission products. The rest of the unexpended fissile material, 239+240Pu, 13.8 kg (3.49 x 10^<13> Bq), was dispersed into the atmosphere along with a fission product, 137Cs, 23.4 g (7.44 x 10^<13>Bq). The fate of 239+240Pu and 137Cs was investigated by analysing both local and global fallout. The highest concentration of 239+240Pu was 64.5 mBq/g (181 mBq/cm2) while it was 188 mBq/g (526 mBq/cm2) for 137Cs both at 2.8 km east from the hypocentre. The total amount of deposition in the local fallout region of 264 km2 was 37.5 g (9.48 x 10^<10>Bq) for 239+240Pu and 3.14 mg (5.88 x 10^<10>Bq) for 137Cs. The ratio of the local fallout against the total amount of the radionuclides released was 0.27% for 239+240Pu and 0.134% for 137Cs. Recent advancements in analytical technology made it possible for artificial radionuclides released from the Nagasaki explosion to be detected in the Arctic ice core layer of 1945. The 239+240Pu and the 137Cs, were measured by collecting 10 ice cores on the Agassiz ice cap, Ellesmere Island, Canada. The deposition was 0.16 μBq/cm2 for 239+240Pu and 20 μBq/cm2 for 137Cs. During the atmospheric testing, the deposition of 239+240Pu and 137Cs varied more than 100 times with the highest peaks of over 50 μBq/cm2 for 239+240Pu and over 800 μBq/cm2 for 137Cs both occurred in 1962. Analyzing Arctic data, there are many new information for long global transport, the history of nuclear weapons development etc.
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