Phenomena identification ranking tables for accident tolerant fuel designs applicable to severe accident conditions

Khatib-Rahbar, M.*; Barrachin, M.*; Denning, R.*; Gabor, J.*; Gauntt, R.*; Herranz, L. E.*; Hobbins, R.*; Jacquemain, D.*; Maruyama, Yu; Metcalf, J.*; et al.

NUREG/CR-7282, ERI/NRC 21-204 (Internet), 160 Pages, 2021/04

Effects of -radiation on a direct disposal system for spent nuclear fuel, 2; Review of research into safety assessments of direct disposal of spent nuclear fuel in Europe and North America

Kitamura, Akira; Takase, Hiroyasu*; Metcalfe, R.*; Penfold, J.*

Journal of Nuclear Science and Technology, 53(1), p.19 - 33, 2016/01

https://doi.org/10.1080/00223131.2015.1014874

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. Therefore, the influences of radiation, which are not expected to be significant in the case of geological disposal of vitrified waste, must be considered in safety assessments for direct disposal of SF. Focusing especially on the effects of -radiation in safety assessment, this study has reviewed safety assessments in countries other than Japan that are planning direct disposal of SF. The review has identified issues relevant to safety assessment for the direct disposal of SF in Japan.

Long-term stability of fracture systems and their behaviour as flow paths in uplifting granitic rocks from the Japanese orogenic field

Yoshida, Hidekazu*; Metcalfe, R.*; Ishibashi, Masayuki; Minami, Masayo*

Geofluids, 13(1), p.45 - 55, 2013/02

https://doi.org/10.1111/gfl.12008

In granitic rocks fracture networks provide pathways for groundwater flow and solute transport that need to be understood to assess the long-term performance of deep underground environment. In order to clarify the long-term processes, Japanese plutons of different ages were studied. Detailed investigation of in-situ fracture fillings sampled from a depth of 300 meters was carried out to clarify the fracturing and mineral infilling processes. Different plutons show identical episodes, consisting of: brittle tensile fracturing (Stage I); relatively rapid uplifting accompanied by hydrothermal water circulation that produced fracture fillings (Stage II); and a period of low-temperature meteoric water circulation (Stage III). The paragenesis of carbon isotopic compositions of carbonate minerals show that there were distinct episodes of mineral precipitation. The evolution of fillings identified here enable development of a model of fracturing and persistence of fluid conducting systems.

Proposal for quality assessment method of groundwater chemistry for hydrochemical investigation

Mizuno, Takashi; Metcalfe, R.*; Iwatsuki, Teruki; Mie, Hideki*

Chikasui Gakkai-Shi, 49(2), p.139 - 152, 2007/05

https://doi.org/10.5917/jagh1987.49.139

Hydrochemical studies are generally conducted based on chemical data of groundwater samples. Various methodologies exist for obtaining samples and for assessing the quality of the collected sample. This study is aimed at establishing a methodology for quality assessment of chemical data obtained from groundwater samples using a method known as Evidence Support Logic. In this study, pH data of groundwater obtained from several boreholes were assessed using this method. The results showed that 23 out of 63 samples satisfied the applied quality criteria. When plotted, the data from the 23 samples show a constant value from top to bottom of investigation area when compared to a plot using data from all samples. These results indicate that the quality assessment method demonstrated by this study is applicable to groundwater studies and that by considering the sample quality it will be possible to develop a clearer interpretation of the deep underground geochemical environment.

An Overview of a natural analogue study of the Tono Uranium Deposit, central Japan

Sasao, Eiji; Ota, Kunio; Iwatsuki, Teruki; Niizato, Tadafumi; Arthur, R. C,*; Stenhouse, M. J.*; Zhou, W.*; Metcalfe, R.*; Takase, Hiroyasu; MacKenzie, A. B.*

Geochemistry; Exploration, Environment, Analysis, 6(1), p.5 - 12, 2006/02

The present natural analogue study of the Tono uranium deposit (Tono Natural Analogue Project) was started in 2001 with the main aim of studying a worst case scenario for safety assessment. The project has involved characterising the geology, hydrogeology, geochemistry and microbiology of the deposit and obtaining quantitative information about specific times in the past, as a means for developing, and building confidence in, conceptual and numerical models. Some recent results from site investigations, such as depositional age of the host sedimentary sequence and fault activity, are presented in this paper and in other papers in the series.

The Hydrogeochemistry of argillaceous rock formations at the Horonobe URL site, Japan

Hama, Katsuhiro; Kunimaru, Takanori; Metcalfe, R.*

Proceedings of 2nd International Meeting on Clays in Natural and Engineered Barriers for Radioactive Waste Confinement, p.399 - 400, 2005/03

The current status of the hydrogeochemical study has been presented.

Study on synthesis of geological environment at Horonobe area; A technical review, 2

Takase, Hiroyasu*; Metcalfe, R.*; Inagaki, Manabu*; Noguchi, Toshihide*; Aoyama, Yuji*; Takase, Kyoko*; Tabara, Michiko*

JNC TJ5400 2003-006, 264 Pages, 2004/02

JNC-TJ5400-2003-006(errata).pdf:0.08MB
JNC-TJ5400-2003-006-1.pdf:83.88MB
JNC-TJ5400-2003-006-2.pdf:15.97MB

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Project to develop a coupled geochemical/hydrogeological model of the Tono area

Sugita, Kenichiro*; Metcalfe, R.*

JNC TJ7400 2005-073, 181 Pages, 2003/03

JNC-TJ7400-2005-073.PDF:7.43MB

This document is the report of a project to develop a coupled geochemical/hydrogeological model of the groundwater system in the Tono area of Gifu ken, central Japan. a major outcome of the work has been identify alternative possible origins for the Na-(Ca)-Cl dominated groundwater salinity in the southern part of the study area.

Generic Implications for Engineered Barriers from a Study of the Tsukiyoshi Fault, Tono, Gifu-ken, Japan

Metcalf; Hama, Katsuhiro; ; Mizuno, Takashi; McCrank

General Meeting of the International Mineralogical Association, P. 296, 2002/11

At any future site for radioactive waste disposal by deep burial, geosphere characterisics will determine to a large extent the most appropriate engineered barrier design. Relevant characteristics include geotechnical properties, permeability, porosity, and geochemical buffering capacity. These characteristics will determine the most appropriate barrier materials, construction methods and barrier orientation. Barrier design must therefore consider the effects of any faulting, which must be determined during site characterisation. However, it is valuable to plan site-specific fault characterisation using a generic understanding of fault properties. The data obtained were interpreted together with hydrogeological and wireline data. The fault has a complex architecture, with a deformation zon

Isotopic and morphological features of fracture calcite from granitic rocks of the Tono area, Japan: a promising palaeohydrogeological tool

; ; Metcalf; Yoshida, Hidekazu;

Applied Geochemistry, 17(9), p.1241 - 1257, 2002/00

https://doi.org/10.1016/S0883-2927(01)00129-9

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