Fukushima Daiichi fuel debris simulant materials for the development of cutting and collection technologies

Journeau, Christophe; Roulet, Damien; Porcheron, Emmanuel; Piluso, Pascal; Chagnot, Christophe

doi:10.1080/00223131.2018.1462267

Cited by 35 publications

(12 citation statements)

References 15 publications

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“…Then, melting of the fuel element leads to the formation of a (partially) oxidized corium melt that can dissolve some of the steel structures. The main constituents of in-vessel fuel debris are thus: fuel (uranium -and transuraniam -oxides, non-volatilized fission products); partly oxidized Zircaloy (mainly zirconium and tin), steel (+ activation products) and boron carbide decomposition products [19]. From inventory, it appears, assuming full oxidation of zirconium, the UO 2 :ZrO 2 ratio is around 1:0.44 [20].…”

Section: Estimated Range Of Compositionmentioning

confidence: 99%

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

Grambow

Nitta

Shibata

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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Section: Estimated Range Of Compositionmentioning

confidence: 99%

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

Grambow

Nitta

Shibata

et al. 2021

Journal of Nuclear Science and Technology

Self Cite

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“…However, in practical accidents, molten corium stratifies between fuel and structural components due to density differences [24,25]. If the material distribution in the fuel debris were not homogeneous, it would affect the selection of the cutting devices [26], aerosol removal management [26,27], and even re-criticality management for fuel debris retrieval [28].…”

Section: Unit 1 In 1f Nppsmentioning

confidence: 99%

Investigation of the Outflow and Spreading-Solidification Behaviour of Stratified Molten Metal

Yokoyama

Kondo

Suzuki

et al. 2021

JNE

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The spreading-solidification behaviour of the stratified molten metals was investigated. This is important in understanding the practical fuel debris distribution spread and solidified in the primary containment vessel (PCV) of Fukushima Daiichi Nuclear Power Plants (1F NPPs). In this study, the effect of outflow diameter on the material distribution before discharging was studied both experimentally and numerically. The two simulant metals were chosen so that the density ratio could be similar to the practical fuel and structure elements of the plant. They were arranged in a vessel and discharged on a receiving plate. The spreading experiments were performed using various outlet diameters with a density and reverse density stratification arrangement. After the experiment, X-ray analysis was performed to evaluate the material distribution in the solidified material. Moreover, a numerical analysis was performed to reveal the mechanisms that affect the material distribution after solidification. As a result, the low-density metal accumulated at the centre region regardless of the outlet diameters in the density stratification. In contrast, the outlet diameters affected the material distribution in the reverse density stratification because they affected the material outflow order. These findings may help increase our understanding of the fuel debris distribution in 1F NPPs.

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“…As for the FDNPP, the waste management of the fuel debris and low-level wastes including spent ion exchange media were studied [1][2][3]. The various types of materials (stainless steel, zircaloy, sintered ceramic, cast-fused zirconia, metal + ceramic, melted inactive simulants, prototypic fuel debris, and irradiated fuel debris simulant) were studied for developing cutting and collecting techniques for the fuel debris.…”

Section: Editorial Summarymentioning

confidence: 99%

“…The various types of materials (stainless steel, zircaloy, sintered ceramic, cast-fused zirconia, metal + ceramic, melted inactive simulants, prototypic fuel debris, and irradiated fuel debris simulant) were studied for developing cutting and collecting techniques for the fuel debris. Laser cutting technique for the various simulants of the debris showed good performance, however, confirmatory experiments are still necessary with prototypic fuel debris, in particular with respect to the generation of airborne dusts and fumes [1]. The calculation methodology of radioactivity inventories in wastes at the FDNPP was developed by considering the distribution of radionuclide material balance and constructing calculation flowcharts of the transportation of radionuclide into waste for the reasonable and sustainable waste management for the decommissioning of FDNPP [2].…”

Section: Editorial Summarymentioning

confidence: 99%

Recent activities in the field of nuclear waste management

Sakamoto

Saito

2019

Journal of Nuclear Science and Technology

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Fukushima Daiichi fuel debris simulant materials for the development of cutting and collection technologies

Cited by 35 publications

References 15 publications

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

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

Investigation of the Outflow and Spreading-Solidification Behaviour of Stratified Molten Metal

Recent activities in the field of nuclear waste management

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