Nuclide inventory calculation based on modeled fuel assembly specifications and burnup histories for Fukushima Dai-ichi NPP Units 1–3

Yamamoto, Toru; Sakai, Tomohiro; Iwahashi, Daiki

doi:10.1080/00223131.2018.1527261

“…The fuel assemblies in the 1 F NPS unit 3 consisted of UO 2 and MOX fuel rods and had reached 40.50 GWd/t through a five-cycle operation [10]. In this study, a MOX fuel rod irradiated up to 43 GWd/t in the advanced thermal reactor Fugen was used.…”

Section: Preparation Of Leaching Samples From Irradiated Mox Fuel Rodsmentioning

confidence: 99%

Leaching behavior of radionuclides from samples prepared from spent fuel rod comparable to core debris in the 1F NPS

Onishi

¹

,

Maeda

²

,

Katsuyama

³

2020

Journal of Nuclear Science and Technology

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To investigate the leaching behavior of radioactive nuclides in leaching samples comparable to core debris (partially molten ZrO 2 /UO 2 between fuel rods) in the Fukushima Daiichi Nuclear Power Station (1 F NPS), the concentration of radionuclides in the leaching solution was measured. The leaching behaviors of actinides (U, Pu, and Np) and Cs from the samples were similar to those from spent fuel. As predicted from the current thermodynamic database, the leaching of U and Pu depends on the pH in the cooling water of the core debris. However, if Mo and Tc are surrounded by zircaloy in the core debris, their leaching amount may increase by one order of magnitude than those from spent fuel.

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“…Extensive information allowed assessing the quantities of released radioactivity including the exposures of the public. The total release to the atmosphere of 131 I was within the range of about 100 to about 500 PBq, and that of 137 Cs was generally in the range of 6 to 20 PBq [2]. While no discernable adverse health effects among Fukushima Prefecture residents have been documented by UNSCEAR (United Nations Scientific Committee on the Effects of Atomic Radiation) that are directly attributable to radiation exposure from the FDNPS accident, and although much effort has focused on the remediation of the radioactively-contaminated site in the prefecture of Fukushima, the roadmap for a societally acceptable cleanup strategy still contains many unknowns on how to reduce safely the environmental and health burdens at an affordable cost.…”

Section: Introductionmentioning

confidence: 89%

“…

Following the NPP accident, several hundred tons of heat-generating corium and fuel debris have been cooled permanently by millions of m 3 of flowing. Knowledge on the interaction with water is crucial for any decommissioning planning.Starting from knowledge on the evolutions of the accident in the three reactor cores and associated fuel debris formations and some additional isotopic and physio-chemical information on debris fragments collected in Fukushima soils, we review the temporal evolution of the chemistry and leached radionuclide contents of the cooling water, comparing measured concentration ratios of the actinides and fission products in the water to reported results of laboratory leaching studies with either spent nuclear fuel or simulated fuel debris.As for spent fuel leaching, the fractions of inventories of 134,137 Cs in the cooling water are orders of magnitude larger than that of the actinides. After more than 10 years of fuel debris/ water contact, 137 Cs release rates have decreased by about a factor of 100.

…”

mentioning

confidence: 99%

“…As for spent fuel leaching, the fractions of inventories of 134,137 Cs in the cooling water are orders of magnitude larger than that of the actinides. After more than 10 years of fuel debris/ water contact, 137 Cs release rates have decreased by about a factor of 100. The total release of actinides from the fuel debris is orders of magnitude lower than that of 134,137 Cs or of 90 Sr.…”

mentioning

confidence: 99%

“…After more than 10 years of fuel debris/ water contact, 137 Cs release rates have decreased by about a factor of 100. The total release of actinides from the fuel debris is orders of magnitude lower than that of 134,137 Cs or of 90 Sr. This high stability makes direct disposal of fuel debris in suitable containers after decommissioning a viable option.…”

mentioning

confidence: 99%

See 2 more Smart Citations

Ten years after the NPP accident at Fukushima : review on fuel debris behavior in contact with water

Grambow

¹

,

Nitta

²

,

Shibata

³

et al. 2021

Journal of Nuclear Science and Technology

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Following the NPP accident, several hundred tons of heat-generating corium and fuel debris have been cooled permanently by millions of m 3 of flowing. Knowledge on the interaction with water is crucial for any decommissioning planning.Starting from knowledge on the evolutions of the accident in the three reactor cores and associated fuel debris formations and some additional isotopic and physio-chemical information on debris fragments collected in Fukushima soils, we review the temporal evolution of the chemistry and leached radionuclide contents of the cooling water, comparing measured concentration ratios of the actinides and fission products in the water to reported results of laboratory leaching studies with either spent nuclear fuel or simulated fuel debris.As for spent fuel leaching, the fractions of inventories of 134,137 Cs in the cooling water are orders of magnitude larger than that of the actinides. After more than 10 years of fuel debris/ water contact, 137 Cs release rates have decreased by about a factor of 100. The total release of actinides from the fuel debris is orders of magnitude lower than that of 134,137 Cs or of 90 Sr. This high stability makes direct disposal of fuel debris in suitable containers after decommissioning a viable option.

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