| Project/Area Number |
13680624
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| Research Category |
Grant-in-Aid for Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
環境影響評価(含放射線生物学)
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| Research Institution | KYOTO UNIVERSITY |
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Principal Investigator |
FUJIKAWA Yoko Kyoto University Research Reactor Institute, Associate Professor, 原子炉実験所, 助教授 (90178145)
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| Co-Investigator(Kenkyū-buntansha) |
FUKUI Masami Kyoto University Research Reactor Institute, Associate Professor, 原子炉実験所, 助教授 (40027462)
SHIZUMA Kiyoshi Hiroshima University Graduate School of Engineering, Professor, 大学院・工学研究科, 教授 (10127657)
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| Project Period (FY) |
2001 – 2002
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| Project Status |
Completed (Fiscal Year 2002)
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| Budget Amount *help |
¥3,200,000 (Direct Cost: ¥3,200,000)
Fiscal Year 2002: ¥1,200,000 (Direct Cost: ¥1,200,000)
Fiscal Year 2001: ¥2,000,000 (Direct Cost: ¥2,000,000)
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| Keywords | URANIUM / HIROSHIMA A-BOMB / ISOTOPE RATIO / LOCAL FALOUT |
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| Research Abstract |
Contents of black rain from the A-bomb are important to clarify the health and environmental hazard caused by nuclear warfare. We analyzed the only existing physical remains of the black rain from Hiroshima A-bomb (Little Boy), a plastered wall with black streaks. Excess ^<137>Cs and anomalous ^<235>U/^<238>U ratios detected in the black residues on the wall confirmed that the black streaks on the wall originated from Little Boy. The results also showed that excess ^<235>U could be used as a fingerprint to clarify the distribution of materials discharged from Little Boy into the environment. High concentrations of Pb and Zn, which may have caused a degree of heavy metal pollution in the area where the rain fell, were also detected in the black rain sample..
Deviation in U-235/U-238 isotope ratio from natural ratio, on the other hand, was not found in soil collected three days after A-bomb detonation in Hiroshima, where approximately 50 kg of U-235 should have been discharged. U-234/U-238 ratio variation in soil that was dependent on the soil particle size and soil digestion procedure was found.
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