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JAEA Reports

Calculation of appropriate oxygen concentration for corrosion inhibition of 9Cr-1Mo steel in molten lead bismuth eutectic

Komatsu, Atsushi

JAEA-Research 2021-019, 24 Pages, 2022/05

JAEA-Research-2021-019.pdf:1.53MB

In order to reduce the corrosion rate of materials in molten lead bismuth eutectic (LBE), it is important to adjust the oxygen concentration, and past reports show that the oxygen concentration is often adjusted to about 10$$^{-7}$$ to 10$$^{-5}$$wt%. However, it is not clearly stated what concentration is optimal, and there are some reports of severe corrosion even within this concentration range. In this study, a corrosion model considering diffusion in oxide and LBE was developed for 9Cr-1Mo steel, and the corrosion control method estimated from the corrosion model were investigated. We also tried to calculate the optimum oxygen concentration to prevent the flow blockage at the low temperature of loop environment while reducing the corrosion of 9Cr-1Mo steel in molten LBE. As a result, it was expected that the corrosion mode of 9Cr-1Mo steel in LBE could be classified into three types, dense film formation, precipitation film formation, and film dissolution, depending on the ratio of oxide film thickness to diffusion layer thickness, iron concentration in LBE, and temperature. In order to inhibit corrosion, it is important to adjust the oxygen concentration so that the conditions for dense film formation can be maintained. For this purpose, it was expected that a pre-oxidized film of more than 10$$^{-7}$$m should be applied before immersion in LBE. The oxygen concentration of about 10$$^{-7}$$ to 10$$^{-5}$$wt% is the appropriate oxygen concentration when the oxide film has grown to some extent, and a higher oxygen concentration was expected to be required when the film is thin.

JAEA Reports

Investigation of environment induced property change and cracking behavior in fuel debris (Contract research); FY2020 Nuclear Energy Science & Technology and Human Resource Development Project

Collaborative Laboratories for Advanced Decommissioning Science; The University of Tokyo*

JAEA-Review 2021-058, 75 Pages, 2022/02

JAEA-Review-2021-058.pdf:4.82MB

The Collaborative Laboratories for Advanced Decommissioning Science (CLADS), Japan Atomic Energy Agency (JAEA), had been conducting the Nuclear Energy Science & Technology and Human Resource Development Project (hereafter referred to "the Project") in FY2020. The Project aims to contribute to solving problems in the nuclear energy field represented by the decommissioning of the Fukushima Daiichi Nuclear Power Station, Tokyo Electric Power Company Holdings, Inc. (TEPCO). For this purpose, intelligence was collected from all over the world, and basic research and human resource development were promoted by closely integrating/collaborating knowledge and experiences in various fields beyond the barrier of conventional organizations and research fields. The sponsor of the Project was moved from the Ministry of Education, Culture, Sports, Science and Technology to JAEA since the newly adopted proposals in FY2018. On this occasion, JAEA constructed a new research system where JAEA-academia collaboration is reinforced and medium-to-long term research/development and human resource development contributing to the decommissioning are stably and consecutively implemented. Among the adopted proposals in FY2020, this report summarizes the research results of the "Investigation of environment induced property change and cracking behavior in fuel debris" conducted in FY2020. The present study aims to investigate the environment induced property change and cracking behavior in fuel debris from the viewpoints of materials science. The research objective is cracking behavior in fuel debris which is presumed to be influenced by environment during long-term fuel debris processing period. The degradation models will be established to simulate the oxidation and hydrogenation processes possibly occurred at fuel debris. The evolution of phase constitution and the corresponding property change in the simulated fuel debris under various environmental conditions will be systematically

Journal Articles

Oxidative decomposition of ammonium ion with ozone in the presence of cobalt and chloride ions for the treatment of radioactive liquid waste

Aihara, Haruka; Watanabe, So; Shibata, Atsuhiro; Mahardiani, L.*; Otomo, Ryoichi*; Kamiya, Yuichi*

Progress in Nuclear Energy, 139, p.103872_1 - 103872_9, 2021/09

Journal Articles

Journal Articles

The Kinetics and mechanism of H$$_{2}$$O$$_{2}$$ decomposition at the U$$_{3}$$O$$_{8}$$ surface in bicarbonate solution

McGrady, J.; Kumagai, Yuta; Watanabe, Masayuki; Kirishima, Akira*; Akiyama, Daisuke*; Kitamura, Akira; Kimuro, Shingo

RSC Advances (Internet), 11(46), p.28940 - 28948, 2021/08

 Times Cited Count:0

JAEA Reports

Technical basis of ECCS acceptance criteria for light-water reactors and applicability to high burnup fuel

Nagase, Fumihisa; Narukawa, Takafumi; Amaya, Masaki

JAEA-Review 2020-076, 129 Pages, 2021/03

JAEA-Review-2020-076.pdf:3.9MB

Each light-water reactor (LWR) is equipped with the Emergency Core Cooling System (ECCS) to maintain the coolability of the reactor core and to suppress the release of radioactive fission products to the environment even in a loss-of-coolant accident (LOCA) caused by breaks in the reactor coolant pressure boundary. The acceptance criteria for ECCS have been established in order to evaluate the ECCS performance and confirm the sufficient safety margin in the evaluation. The limits defined in the criteria were determined in 1975 and reviewed based on state-of-the-art knowledge in 1981. Though the fuel burnup extension and necessary improvements of cladding materials and fuel design have been conducted, the criteria have not been reviewed since then. Meanwhile, much technical knowledge has been accumulated regarding the behavior of high-burnup fuel during LOCAs and the applicability of the criteria to the high-burnup fuel. This report provides a comprehensive review of the history and technical bases of the current criteria and summarizes state-of-the-art technical findings regarding the fuel behavior during LOCAs. The applicability of the current criteria to the high-burnup fuel is also discussed.

Journal Articles

Corrosion property of container using hybrid material for thermal decomposition process of sulfuric acid

Ioka, Ikuo; Kuriki, Yoshiro*; Iwatsuki, Jin; Kawai, Daisuke*; Yokota, Hiroki*; Inagaki, Yoshiyuki; Kubo, Shinji

Proceedings of 2020 International Conference on Nuclear Engineering (ICONE 2020) (Internet), 5 Pages, 2020/08

A thermochemical water-splitting iodine-sulfur processes (IS process) is one of candidates for the large-scale production of hydrogen using heat from solar power. Severe corrosive environment which is thermal decomposition of sulfuric acid exists in the IS process. A hybrid material with the corrosion-resistance and the ductility was made by a plasma spraying and laser treatment. The specimen had excellent corrosion resistance in the condition of 95 mass% boiling sulfuric acid. This was attributed to the formation of SiO$$_{2}$$ on the surface. The container using the hybrid material was experimentally made. The pre-oxidized container using hybrid technique was prepared for the corrosion test in boiling sulfuric acid to evaluate the corrosion characteristics of the container. There was no detaching of the surface with the weld part and the R processing. We proposed the calculation method of corrosion rate from the ions dissolved in the sulfuric acid solution after the corrosion test.

Journal Articles

Oxidation kinetics of silicon carbide in steam at temperature range of 1400 to 1800$$^{circ}$$C studied by laser heating

Pham, V. H.; Nagae, Yuji; Kurata, Masaki; Bottomley, D.; Furumoto, Kenichiro*

Journal of Nuclear Materials, 529, p.151939_1 - 151939_8, 2020/02

AA2019-0197.pdf:1.61MB

 Times Cited Count:2 Percentile:62.87(Materials Science, Multidisciplinary)

Journal Articles

Fracture limit of high-burnup advanced fuel cladding tubes under loss-of-coolant accident conditions

Narukawa, Takafumi; Amaya, Masaki

Journal of Nuclear Science and Technology, 57(1), p.68 - 78, 2020/01

 Times Cited Count:1 Percentile:23.13(Nuclear Science & Technology)

Journal Articles

Behavior of high-burnup advanced LWR fuel cladding tubes under LOCA conditions

Narukawa, Takafumi; Amaya, Masaki

Proceedings of International Nuclear Fuel Cycle Conference / Light Water Reactor Fuel Performance Conference (Global/Top Fuel 2019) (USB Flash Drive), p.912 - 921, 2019/09

Journal Articles

Oxidation of silicon carbide in steam studied by laser heating

Pham, V. H.; Nagae, Yuji; Kurata, Masaki; Furumoto, Kenichiro*; Sato, Hisaki*; Ishibashi, Ryo*; Yamashita, Shinichiro

Proceedings of International Nuclear Fuel Cycle Conference / Light Water Reactor Fuel Performance Conference (Global/Top Fuel 2019) (USB Flash Drive), p.670 - 674, 2019/09

Journal Articles

Oxidation behavior of high-burnup advanced fuel cladding tubes in high-temperature steam

Narukawa, Takafumi; Amaya, Masaki

Journal of Nuclear Science and Technology, 56(7), p.650 - 660, 2019/07

 Times Cited Count:6 Percentile:81.33(Nuclear Science & Technology)

Journal Articles

Experimental determination of the photooxidation of aqueous I$$^{-}$$ as a source of atmospheric I$$_{2}$$

Watanabe, Kosuke*; Matsuda, Shohei; Cuevas, C. A.*; Saiz-Lopez, A.*; Yabushita, Akihiro*; Nakano, Yukio*

ACS Earth and Space Chemistry (Internet), 3(4), p.669 - 679, 2019/04

 Times Cited Count:2 Percentile:26.9(Chemistry, Multidisciplinary)

The photooxidation of aqueous iodide ions (I$$^{-}$$$$_{(aq)}$$) at sea surface results in the emission of gaseous iodine molecules (I$$_{2}$$$$_{(g)}$$) into the atmosphere. It plays a certain role in the transport of iodine from ocean to the atmosphere in the natural cycle of iodine. In this study, we determined the photooxidation parameters, the molar absorption coefficient ($$varepsilon$$$$_{iodide}$$($$lambda$$)) and the photooxidative quantum yields ($$Phi$$$$_{iodide}$$($$lambda$$)) of I$$^{-}$$$$_{(aq)}$$, in the range of 290-500 nm. Through the investigation of the influence of pH and dissolved oxygen (DO) on $$Phi$$$$_{iodide}$$($$lambda$$), the subsequent emission rates of I$$_{2}$$$$_{(g)}$$ following the photooxidation of I$$^{-}$$$$_{(aq)}$$ in deionized water solution (pH 5.6, DO 7.8 mg L$$^{-1}$$) and artificial seawater solution (pH 8.0, DO 7.0 mg L$$^{-1}$$) were estimated. A global chemistry-climate model employed herein to assess the I$$_{2}$$$$_{(g)}$$ ocean emission on a global scale indicated that the photooxidation of I$$^{-}$$$$_{(aq)}$$ by solar light can enhance the atmospheric iodine budget by up to $$sim$$8% over some oceanic regions.

Journal Articles

Effect of re-oxidation rate of additive cations on corrosion rate of stainless steel in boiling nitric acid solution

Irisawa, Eriko; Yamamoto, Masahiro; Kato, Chiaki; Motooka, Takafumi; Ban, Yasutoshi

Journal of Nuclear Science and Technology, 56(4), p.337 - 344, 2019/04

 Times Cited Count:0 Percentile:0.01(Nuclear Science & Technology)

Journal Articles

Effects of ballooning and rupture on the fracture resistance of Zircaloy-4 fuel cladding tube after LOCA-simulated experiments

Yumura, Takanori; Amaya, Masaki

Annals of Nuclear Energy, 120, p.798 - 804, 2018/10

 Times Cited Count:3 Percentile:45.99(Nuclear Science & Technology)

Journal Articles

Improvements in drill-core headspace gas analysis for samples from microbially active depths

Miyakawa, Kazuya; Okumura, Fumiaki*

Geofluids, 2018, p.2436814_1 - 2436814_11, 2018/10

 Times Cited Count:1 Percentile:15.51(Geochemistry & Geophysics)

no abstracts in English

Journal Articles

Oxidation kinetics of Zry-4 fuel cladding in mixed steam-air atmospheres at temperatures of 1273 - 1473 K

Negyesi, M.; Amaya, Masaki

Journal of Nuclear Science and Technology, 54(10), p.1143 - 1155, 2017/10

 Times Cited Count:5 Percentile:58.67(Nuclear Science & Technology)

Journal Articles

Behavior of high-burnup advanced LWR fuels under design-basis accident conditions

Amaya, Masaki; Udagawa, Yutaka; Narukawa, Takafumi; Mihara, Takeshi; Taniguchi, Yoshinori

Proceedings of 2017 Water Reactor Fuel Performance Meeting (WRFPM 2017) (USB Flash Drive), 10 Pages, 2017/09

Journal Articles

Oxidation and reduction behaviors of a prototypic MgO-PuO$$_{2-x}$$ inert matrix fuel

Miwa, Shuhei; Osaka, Masahiko

Journal of Nuclear Materials, 487, p.1 - 4, 2017/04

 Times Cited Count:4 Percentile:50.55(Materials Science, Multidisciplinary)

Oxidation and reduction behaviors of prototypic MgO-based inert matrix fuels (IMFs) containing PuO$$_{2-x}$$ were experimentally investigated by means of thermogravimetry. The oxidation and reduction kinetics of the MgO-PuO$$_{2-x}$$ specimen were determined. The oxidation and reduction rates of the MgO-PuO$$_{2-x}$$ were found to be low compared with those of PuO$$_{2-x}$$. It is note that the changes in O/Pu ratios of MgO-PuO$$_{2-x}$$ from stoichiometry were smaller than those of PuO$$_{2-x}$$ at high oxygen partial pressure. From these results, it can be said that MgO matrix lower the oxygen supply and release of PuO$$_{2-x}$$, which is preferable as the minor actinides incineration devices, since the high oxygen potentials of minor actinide oxides can cause certain problems in terms of thermochemical aspects such as enlarged cladding inner-surface corrosion.

Journal Articles

Corrosion test of HTGR graphite with SiC coating

Chikhray, Y.*; Kulsartov, T.*; Shestakov, V.*; Kenzhina, I.*; Askerbekov, S.*; Sumita, Junya; Ueta, Shohei; Shibata, Taiju; Sakaba, Nariaki; Abdullin, Kh.*; et al.

Proceedings of 8th International Topical Meeting on High Temperature Reactor Technology (HTR 2016) (CD-ROM), p.572 - 577, 2016/11

Application of SiC as corrosion-resistive coating over graphite remains important task for HTGR. This study presents the results of chemical interaction of the SiC gradient coating over the high-density IG-110 graphite with water vapor in the temperature up to 1673 K. The experiments at 100 Pa of water vapor showed that the passive reaction caused to form SiO$$_{2}$$ film on the surface of SiC coating. Active corrosion of SiC in 1Pa of water vapor leads to deposits of various carbon composites on its surface.

239 (Records 1-20 displayed on this page)