Corrosion test of Fugen pressure tube (Zr-2.5wt%Nb alloy) under the sub-surface disposal environment, 2; Examination of long-term corrosion rate by 5 years keeping sample

Sugaya, Toshikatsu; Nakatani, Takayoshi; Sakai, Akihiro

JAEA-Technology 2017-032, 21 Pages, 2018/01

[The article has been found to have a problem about reliability of the corrosion data acquisition, and thus it is unavailable to download the full text in accordance with authors' intentions to retract the report.] For the purpose of the setting of the rate of nuclide elution necessary to safety assessment, we planned the gas-accumulating type corrosion test on Zr-2.5wt%Nb alloy in order to obtain long-term corrosion rate under low temperature, low oxygen and alkaline conditions assuming the disposal environment. A corrosion rate over a testing period of 5 years is acquired with the aim to grasp a long-term corrosion rate behavior in this report. This corrosion rate is compared with the same data that was previously acquired over a testing period of 2 years. As a result, it is confirmed that an evaluation method that is proportional to the minus cubic root of corrosion time squared can be applicable to the corrosion rate behavior acquired this time over a testing period of 5 years, which is the same result in evaluating the corrosion rate behavior acquired over a testing period of 2 years.

International Noble Gas joint measurement at Mutsu City, Aomori for CTBT verification

Kijima, Yuichi; Yamamoto, Yoichi; Oda, Tetsuzo

JAEA-Technology 2017-028, 33 Pages, 2018/01

JAEA-Technology-2017-028.pdf:38.85MB

The International Noble Gas Experiment related to monitoring network for radioactive noble gas (xenon) has been carried out all over the world, as part of the International Monitoring System (IMS) of CTBT. Thirty IMS radionuclide stations including the Takasaki station in Japan are monitoring radioxenon. The past measurement results show that several stations often detect radioxenon and the major emission source of these radioxenon is medical radioisotope production facilities. And nuclear power plants and medical institutions used radioxenon for nuclear medicine diagnosis, and so on are also considered as the possible sources of radioxenon, and it is therefore important to understand the background behavior of radioxenon originated from above facilities for enhancement of monitoring capability for nuclear tests. The international joint measurement was conducted in 2012 by the Preparatory Commission for the CTBT Organization, US Pacific Northwest National Laboratory, Japan Chemical Analysis Center and JAEA at the Ohminato site of JAEA Aomori Research and Development Center in Mutsu city, Aomori, as part of investigation on radioxenon background in East Asia region. In 2014, the additional measurement was carried out at the same place for further investigation. A high sensitive Transportable Xenon Laboratory developed by PNNL was used for this measurement. This paper describes the outline and the results of the joint measurement conducted in 2012 and 2014.

Annual report on the environmental radiation monitoring around the Tokai Reprocessing Plant FY2016

Nakano, Masanao; Fujita, Hiroki; Mizutani, Tomoko; Nemoto, Masashi; Tobita, Keiji; Hosomi, Kenji; Nagaoka, Mika; Hokama, Tomonori; Nishimura, Tomohiro; Koike, Yuko; et al.

JAEA-Review 2017-028, 177 Pages, 2018/01

JAEA-Review-2017-028.pdf:3.61MB

Environmental radiation monitoring around the Tokai Reprocessing Plant has been performed by the Nuclear Fuel Cycle Engineering Laboratories, based on "Safety Regulations for the Reprocessing Plant of Japan Atomic Energy Agency, Chapter IV - Environmental Monitoring". This annual report presents the results of the environmental monitoring and the dose estimation to the hypothetical inhabitant due to the radioactivity discharged from the plant to the atmosphere and the sea during April 2016 to March 2017. In this report, some data include the influence of the accidental release from the Fukushima Daiichi Nuclear Power Station of Electric Power Company Holdings, Inc. in March 2011. Appendices present comprehensive information, such as monitoring programs, monitoring methods, monitoring results and their trends, meteorological data and discharged radioactive wastes. In addition, the data which were influenced by the accidental release and were exceeded the normal range of fluctuation in the monitoring, were evaluated.

Development of correlation of gaseous ruthenium transfer rate to condensed water in accident of evaporation to dryness by boiling of reprocessed high level liquid waste in Fuel Reprocessing Facilities

Yoshida, Kazuo; Tamaki, Hitoshi; Yoshida, Naoki; Amano, Yuki; Abe, Hitoshi

JAEA-Research 2017-015, 18 Pages, 2018/01

JAEA-Research-2017-015.pdf:3.08MB

An accident of evaporation to dryness by boiling of high level liquid waste is postulated as one of the severe accidents at a fuel reprocessing facility. It was observed at the experiments that a large amount of ruthenium (Ru) is volatilized and transfer to the vapor phase in the tank. The nitric acid and water mixed vapor released from the tank is condensed. Volatilized Ru is expected to transfer into the condensed water at the compartments in the building. Quantitative estimation of the amount of Ru transferred condensed water is key issues to evaluate the reduction the amount of Ru through leak path in the facility building. This report presents that a correlation has been developed for Ru transfer rate to condensed water with vapor condensing rate based on the experimental results and additional thermal-hydraulic simulation of the experiments. Applicability of the correlation has been also demonstrated with the accident simulation of typical facilities in full-scale.

Proceedings of the 2016 Symposium on Nuclear Data; November 17-18, 2016, High Energy Accelerator Research Organization, Tsukuba, Ibaraki, Japan

Sanami, Toshiya*; Nishio, Katsuhisa; Hagiwara, Masayuki*; Iwase, Hiroshi*; Kunieda, Satoshi; Nakamura, Shoji

JAEA-Conf 2017-001, 222 Pages, 2018/01

JAEA-Conf-2017-001.pdf:30.89MB

The 2016 Symposium on Nuclear Data was held at Kobayashi Hall of High Energy Accelerator Research Organization, on November 17 and 18, 2016. The symposium was organized by the Nuclear Data Division of the Atomic Energy Society of Japan in cooperation with Radiation Science Center, High Energy Accelerator Research Organization, Nuclear Science and Engineering Center of Japan Atomic Energy Agency and North Kanto Branch of Atomic Energy Society of Japan. In the symposium, there were one tutorial, "Historical Evolution of Accelerators" and four oral sessions, "Overview of the ImPACT Program - Reduction and Resource Recycling of High Level Wastes through Nuclear Transmutation", "Facilities and experiments for nuclear data in Japan", "Nuclear data from measurement to application", and "Progress of neutron nuclear data measurement and research for its basics and application". In addition, recent research progress on experiments, evaluation, benchmark and application was presented in the poster session. Among 65 participants, all presentations and following discussions were very active and fruitful. This report consists of total 31 papers including 10 oral and 21 poster presentations.

Development plan of austenitic Fe and Ni based alloys with improved corrosion resistance to sulfuric acid and HI fluids of industrial processes

Hirota, Noriaki; Iwatsuki, Jin; Imai, Yoshiyuki; Yan, X.

JAEA-Technology 2017-027, 19 Pages, 2017/12

JAEA-Technology-2017-027.pdf:2.08MB

In this study, austenitic Fe-based alloys and Ni based alloys was developed as candidate structural materials for equipment operated in sulfuric acid and hydrogen iodide (HI) environment, which exists in various industrial processes including iodine-sulfur (IS) hydrogen production process and geothermal power generation process. The objectives of the study are to achieve the corrosion resistance performance sufficient under the working condition of these processes and to overcome the practical scale-up difficulty of the ceramic (SiC) material that is presently used in the processes due to the manufacturing size limitation of the ceramic. The chemical composition development plan for the austenitic Fe-based alloys is threefold: reinforcement of matrix by addition of Cu and Ta, strength compensation of the surface film by addition of Si and Ti, and prevention of peeling of surface oxide by addition of rare earth elements. Because addition of Cu and Si is known to reduce the ductility of the material and thus manufacturability of the component, it is important to determine the allowable amount of each element to be added. On the other hand, the chemical composition development plan for the Ni based alloys is reinforcement of matrix by addition of Mo, W and Ta, strength compensation of the surface film by addition of Ti, and prevention of peeling of surface oxide by addition of rare earth elements. In particular, the addition of Mo and W to the Ni based alloy is expected to be effective in preventing dimensional deviation of structures from increasing during heating and cooling of process equipment. Various material specimens will be fabricated based on the above chemical composition development plans and tests on these specimens will then be carried out to confirm the corrosion resistance performance under the fluid conditions simulating each industrial processes.