Volatilization of B4C control rods in Fukushima Daiichi nuclear reactors during meltdown: B-Li isotopic signatures in cesium-rich microparticles.
J Hazard Mater
; 428: 128214, 2022 04 15.
Article
em En
| MEDLINE
| ID: mdl-35042164
ABSTRACT
Boron carbide control rods remain in the fuel debris of the damaged reactors in the Fukushima Daiichi Nuclear Power Plant, potentially preventing re-criticality; however, the state and stability of the control rods remain unknown. Sensitive high-resolution ion microprobe analyses have revealed B-Li isotopic signatures in radioactive Cs-rich microparticles (CsMPs) that formed by volatilization and condensation of Si-oxides during the meltdowns. The CsMPs contain 1518-6733 mg kg-1 of 10+11B and 11.99-1213 mg kg-1 of 7Li. The 11B/10B (4.15-4.21) and 7Li/6Li (213-406) isotopic ratios are greater than natural abundances (~4.05 and ~12.5, respectively), indicating that 10B(n,α)7Li reactions occurred in B4C prior to the meltdowns. The total amount of B released with CsMPs was estimated to be 0.024-62 g, suggesting that essentially all B remains in reactor Units 2 and/or 3 and is enough to prevent re-criticality; however, the heterogeneous distribution of B needs to be considered during decommissioning.
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1
Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Monitoramento de Radiação
/
Acidente Nuclear de Fukushima
País/Região como assunto:
Asia
Idioma:
En
Ano de publicação:
2022
Tipo de documento:
Article