An Introduction to spent nuclear fuel decay heat for light water reactors; A Review from the NEA WPNCS

Rochman, D.*; Minato, Futoshi; Watanabe, Tomoaki; 52 of others*

EPJ Nuclear Sciences & Technologies (Internet), 10, p.9_1 - 9_83, 2024/10

https://doi.org/10.1051/epjn/2024010

Consideration on roles and relationship between observations/measurements and model predictions for environmental consequence assessments for nuclear facilities

Togawa, Orihiko; Okura, Takehisa; Kimura, Masanori

JAEA-Review 2022-049, 76 Pages, 2023/01

JAEA-Review-2022-049.pdf:3.74MB

Before construction and after operation of nuclear facilities, environmental consequence assessments are conducted for normal operation and an emergency. These assessments mainly aim at confirming safety for the public around the facilities and producing relief for them. Environmental consequence assessments are carried out using observations/ measurements by environmental monitoring and/or model predictions by calculation models, sometimes using either of which and at other times using both them, according to the situations and necessities. First, this report investigates methods, roles, merits/demerits and relationship between observations/measurements and model predictions which are used for environmental consequence assessments of nuclear facilities, especially holding up a spent nuclear fuel reprocessing plant at Rokkasho, Aomori as an example. Next, it explains representative examples of utilization of data on observations/measurements and results on model predictions, and considers points of attention at using them. Finally, the report describes future direction, for example, improvements of observations/measurements and model predictions, and fusion of both them.

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

Onishi, Takashi; Maeda, Koji; Katsuyama, Kozo

Journal of Nuclear Science and Technology, 58(4), p.383 - 398, 2021/04

https://doi.org/10.1080/00223131.2020.1822943

Determination of Pd in Pd purified by selective precipitation from spent nuclear fuel by laser ablation ICP-MS

Asai, Shiho; Ohata, Masaki*; Yomogida, Takumi; Saeki, Morihisa*; Oba, Hironori*; Hanzawa, Yukiko; Horita, Takuma; Kitatsuji, Yoshihiro

Analytical and Bioanalytical Chemistry, 411(5), p.973 - 983, 2019/02

https://doi.org/10.1007/s00216-018-1527-3

Determination of radiopalladium Pd is required for ensuring the radiation safety of Pd extracted from spent nuclear fuel for recycling or disposal. We employed laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) to simplify an analytical procedure of Pd. Pd was separated through selective Pd precipitation reaction from spent nuclear fuel. Laser ablation allows direct measurement of the Pd precipitates, skipping the dissolution and dilution procedure. In this study, Pd in natural Pd standard solution was used as an internal standard, taking advantage of its absence in spent nuclear fuel. The Pd precipitate was uniformly embedded on the surface of the centrifugal filter, forming a microscopically thin flat surface of Pd. The resulting homogeneous Pd layer is suitable for obtaining a stable signal ratio of Pd/Pd. The amount of Pd obtained by LA-ICP-MS corresponds to the values obtained by conventional solution nebulization measurement.

Effects of -radiation on a direct disposal system for spent nuclear fuel, 1 Review of research into the effects of -radiation on the spent nuclear fuel, canisters and outside canisters

Kitamura, Akira; Takase, Hiroyasu*

Journal of Nuclear Science and Technology, 53(1), p.1 - 18, 2016/01

https://doi.org/10.1080/00223131.2015.1018362

Not only geological disposal of vitrified waste generated by spent fuel (SF) reprocessing, but also the possibility of disposing of SF itself in deep geological strata (hereinafter "direct disposal of SF") may be considered in the Japanese geological disposal program. In the case of direct disposal of SF, the radioactivity of the waste is higher and the potential effects of the radiation are greater. Specific examples of the possible effects of radiation include: increased amounts of canister corrosion; generation of oxidizing chemical species in conjunction with radiation degradation of groundwater and accompanying oxidation of reducing groundwater; and increase in the dissolution rate and the solubility of SF. Focusing especially on the effects of -radiation in safety assessment, this study has reviewed research into the effects of -radiation on the spent nuclear fuel, canisters and outside canisters.

Influence of contaminants from spent fuel pools at the Fukushima Daiichi Nuclear Power Station on the reprocessing process

Aihara, Haruka; Kitawaki, Shinichi; Nomura, Kazunori; Taguchi, Katsuya

Proceedings of 21st International Conference & Exhibition; Nuclear Fuel Cycle for a Low-Carbon Future (GLOBAL 2015) (USB Flash Drive), p.1076 - 1083, 2015/09

On the requirement for remodelling the spent nuclear fuel transportation casks for research reactors; A Review of the drop impact analyses of JRC-80Y-20T

Review Group on the Structure of the Spent Nuclear Fuel Transportation Casks for

JAERI-Review 2005-023, 133 Pages, 2005/07

JAERI-Review-2005-023.pdf:18.88MB

The Japan Atomic Energy Research Institute (JAERI) constructed two stainless steel transportation casks, JRC-80Y-20T, for spent nuclear fuels of research reactors and had utilized them for transportation since 1981. A modification of the design was applied to the USA for transportation of silicide fuels. Additional analyses employing the impact analysis code LS-DYNA that was often used for safety analysis were submitted by the JAERI to the USA to show integrity of the packages; the casks were still not approved, because inelastic deformation was occurred on the surface of the lid touching to the body. To resolve this problem on design approval of transportation casks, a review group was formed at the end of this June. The group examined the impact analyses by reviewing the input data and performing the sensitivity analyses. As the drop impact analyses were found to be practically reasonable, it was concluded that the approval of the USA for the transportation casks could not be obtained just by revising the analyses; therefore, remodelling the casks is required.

ARTIST process; A Novel chemical process for treatment of spent nuclear fuel

Tachimori, Shoichi

JAERI-Research 2001-048, 23 Pages, 2001/10

JAERI-Research-2001-048.pdf:1.88MB

A new chemical process, ARTIST process, is proposed for the treatment of spent nuclear fuel. The main concept of the ARTIST process is to recover and stock all actinides (Ans) in two groups, uranium (U) and a mixture of transuranics (TRU), to preserve their resource value and to dispose solely fission products (FPs). The process composed of two main steps, an U exclusive isolation and a total recovery of TRU; which copes with the nuclear non-proliferation measures, and additionally Pu separation process and soft N-donor process if requested, and optionally processes for separation of long-lived FPs. These An products: U-product and TRU-product, are to be solidified by calcination and allowed to the interim stockpile for future utilization. These separations are achieved by use of amidic extractants in accord with the CHON principle. The technical feasibility of the ARTIST process was explained by the performance of both the branched-alkyl monoamides the diglycolic amide (TODGA) in thorough extraction of all TRU by tridentate fashon.

LIBS for "Fukushima"; Current results and challenge as a remote in-situ screening analysis

Wakaida, Ikuo; Oba, Hironori; Oba, Hironori*; Akaoka, Katsuaki; Karino, Takahiro; Nakanishi, Ryuzo*; Sakamoto, Kan*; Ikeda, Yuji*; Taira, Takunori*

no journal, , 

Challenging and development on radiation hardend laser remote analysis for in-situ screening of nuclear fuel debris in decommissioning of Fukushima Daiichi Nuclear Power Station

Wakaida, Ikuo; Oba, Hironori; Akaoka, Katsuaki; Karino, Takahiro; Nakanishi, Ryuzo*; Sakamoto, Kan*; Ikeda, Yuji*; Taira, Takunori*

no journal, ,