TY - JOUR
T1 - Volatilization of B4C control rods in Fukushima Daiichi nuclear reactors during meltdown
T2 - B–Li isotopic signatures in cesium-rich microparticles
AU - Fueda, Kazuki
AU - Takami, Ryu
AU - Minomo, Kenta
AU - Morooka, Kazuya
AU - Horie, Kenji
AU - Takehara, Mami
AU - Yamasaki, Shinya
AU - Saito, Takumi
AU - Shiotsu, Hiroyuki
AU - Ohnuki, Toshihiko
AU - Law, Gareth T.W.
AU - Grambow, Bernd
AU - Ewing, Rodney C.
AU - Utsunomiya, Satoshi
N1 - Funding Information:
This work was partially supported by the Grant-in-Aid for Scientific Research (KAKENHI) from the Japan Society for the Promotion of Science ( 16K12585 , 16H04634 ).
Publisher Copyright:
© 2022 Elsevier B.V.
PY - 2022/4/15
Y1 - 2022/4/15
N2 - 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.
AB - 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.
UR - http://www.scopus.com/inward/record.url?scp=85122805035&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=85122805035&partnerID=8YFLogxK
U2 - 10.1016/j.jhazmat.2022.128214
DO - 10.1016/j.jhazmat.2022.128214
M3 - Article
C2 - 35042164
AN - SCOPUS:85122805035
SN - 0304-3894
VL - 428
JO - Journal of Hazardous Materials
JF - Journal of Hazardous Materials
M1 - 128214
ER -