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Journal Articles

Repeatability and reproducibility of measurements of low dissolved radiocesium concentrations in freshwater using different pre-concentration methods

Kurihara, Momo*; Yasutaka, Tetsuo*; Aono, Tatsuo*; Ashikawa, Nobuo*; Ebina, Hiroyuki*; Iijima, Takeshi*; Ishimaru, Kei*; Kanai, Ramon*; Karube, Jinichi*; Konnai, Yae*; et al.

Journal of Radioanalytical and Nuclear Chemistry, 322(2), p.477 - 485, 2019/11

We assessed the repeatability and reproducibility of methods for determining low dissolved radiocesium concentrations in freshwater in Fukushima. Twenty-one laboratories pre-concentrated three of 10 L samples by five different pre-concentration methods (prussian-blue-impregnated filter cartridges, coprecipitation with ammonium phosphomolybdate, evaporation, solid-phase extraction disks, and ion-exchange resin columns), and activity of radiocesium was measured. The z-scores for all of the $$^{137}$$Cs results were within $$pm$$2, indicating that the methods were accurate. The relative standard deviations (RSDs) indicating the variability in the results from different laboratories were larger than the RSDs indicating the variability in the results from each separate laboratory.

Journal Articles

Enhancing emergency response in the field based on analysis of workload distribution at Fukushima Daiichi Nuclear Power Station

Yoshizawa, Atsufumi*; Oba, Kyoko; Kitamura, Masaharu*

Nippon Genshiryoku Gakkai Wabun Rombunshi, 18(2), p.55 - 68, 2019/06

This study aims to improve the potential of an emergency response by analyzing the workload management during the accident at the Emergency Response Center (ERC) of TEPCO's Fukushima Daiichi Nuclear Power Plant. Specifically, the research focused on the response of the ERC during the time between the discontinuation of Unit 3 core water injection and its recovery. It identified the different types of workload at the ERC had and how they had been managed based on the record of a TV conference. It also deduced the casual factors of the responses, supplementing the interview record of the director of ERC at the time by applying workload management analysis. On the basis of these findings, lessons to enhance the potential of the on-site emergency response have been obtained for ERC and outside organizations.

Journal Articles

Improvement of plant reliability based on combining of prediction and inspection of crack growth due to intergranular stress corrosion cracking

Uchida, Shunsuke; Chimi, Yasuhiro; Kasahara, Shigeki; Hanawa, Satoshi; Okada, Hidetoshi*; Naito, Masanori*; Kojima, Masayoshi*; Kikura, Hiroshige*; Lister, D. H.*

Nuclear Engineering and Design, 341, p.112 - 123, 2019/01

 Percentile:100(Nuclear Science & Technology)

Improvement of plant reliability based on reliability-centered-maintenance (RCM) is going to be undertaken in NPPs. RCM is supported by risk-based maintenance (RBM). The combination of prediction and inspection is one of the key issues to promote RBM. Early prediction of IGSCC occurrence and its propagation should be confirmed throughout the entire plant systems which should be accomplished by inspections at the target locations followed by timely application of suitable countermeasures. From the inspections, accumulated data will be applied to confirm the accuracy of the code, to tune some uncertainties of the key data for prediction, and then, to increase their accuracy. The synergetic effects of prediction and inspection on application of effective and suitable countermeasures are expected. In the paper, the procedures for the combination of prediction and inspection are introduced.

Journal Articles

Application of nuclear data to the decommissioning of the Fukushima Daiichi Nuclear Power Station

Okumura, Keisuke; Riyana, E. S.

JAEA-Conf 2018-001, p.63 - 68, 2018/12

The decommissioning of the Fukushima Daiichi Nuclear Power Station (1F) is an unexplored field. Although the investigations for inside primary containment vessel (PCV) by robots have been underway by IRID, actual situation inside the PCV and the characteristics of fuel debris have not been sufficiently clarified yet. Under such circumstances, the computational simulation with reliable data is an effective means for solving many problems for the 1F decommissioning. Here, as application examples using nuclear data such as JENDL-4.0, we will introduce some researches and developments on (1) prediction of dose rate distribution in PCV, (2) remotely operated vehicle (ROV) system to explore submerged fuel debris in PCV, (3) non-destructive assay of nuclear fuel materials in a fuel debris canister.

JAEA Reports

Confirmation tests for Warm Pre-stress (WPS) effect in reactor pressure vessel steel (Contract research)

Chimi, Yasuhiro; Iwata, Keiko; Tobita, Toru; Otsu, Takuyo; Takamizawa, Hisashi; Yoshimoto, Kentaro*; Murakami, Takeshi*; Hanawa, Satoshi; Nishiyama, Yutaka

JAEA-Research 2017-018, 122 Pages, 2018/03

JAEA-Research-2017-018.pdf:44.03MB

Warm pre-stress (WPS) effect is a phenomenon that after applying a load at a high temperature fracture does not occur in unloading during cooling, and then the fracture toughness in reloading at a lower temperature increases effectively. Engineering evaluation models to predict an apparent fracture toughness in reloading are established using experimental data with linear elasticity. However, there is a lack of data on the WPS effect for the effects of specimen size and surface crack in elastic-plastic regime. In this study, fracture toughness tests were performed after applying load-temperature histories which simulate pressurized thermal shock transients to confirm the WPS effect. The experimental results of an apparent fracture toughness tend to be lower than the predictive results using the engineering evaluation models in the case of a high degree of plastic deformation in preloading. Considering the plastic component of preloading can refine the engineering evaluation models.

Journal Articles

Challenges for enhancing Fukushima environmental resilience, 10; Dose evaluation and risk communication

Saito, Kimiaki; Takahara, Shogo; Uezu, Yasuhiro

Nippon Genshiryoku Gakkai-Shi, 60(2), p.111 - 115, 2018/02

no abstracts in English

Journal Articles

CIELO collaboration summary results; International evaluations of neutron reactions on uranium, plutonium, iron, oxygen and hydrogen

Chadwick, M. B.*; Capote, R.*; Trkov, A.*; Herman, M. W.*; Brown, D. A.*; Hale, G. M.*; Kahler, A. C.*; Talou, P.*; Plompen, A. J.*; Schillebeeckx, P.*; et al.

Nuclear Data Sheets, 148, p.189 - 213, 2018/02

 Times Cited Count:8 Percentile:4(Physics, Nuclear)

The CIELO collaboration has studied neutron cross sections on nuclides that significantly impact criticality in nuclear facilities - $$^{235}$$U, $$^{238}$$U, $$^{239}$$Pu, $$^{56}$$Fe, $$^{16}$$O and $$^{1}$$H - with the aim of improving the accuracy of the data and resolving previous discrepancies in our understanding. This multi-laboratory pilot project, coordinated via the OECD/NEA Working Party on Evaluation Cooperation (WPEC) Subgroup 40 with support also from the IAEA, has motivated experimental and theoretical work and led to suites of new evaluated libraries that accurately reflect measured data and also perform well in integral simulations of criticality. This report summarizes our results and outlines plans for the next phase of this collaboration.

JAEA Reports

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.

Journal Articles

RELAP5 uncertainty evaluation using ROSA/LSTF test data on PWR 17% cold leg intermediate-break LOCA with single-failure ECCS

Takeda, Takeshi; Otsu, Iwao

Annals of Nuclear Energy, 109, p.9 - 21, 2017/11

 Times Cited Count:1 Percentile:64.68(Nuclear Science & Technology)

Journal Articles

Axial flow characteristics of bubbly flow in a vertical large-diameter square duct

Shen, X.*; Sun, Haomin; Deng, B.*; Hibiki, Takashi*; Nakamura, Hideo

Proceedings of 17th International Topical Meeting on Nuclear Reactor Thermal Hydraulics (NURETH-17) (USB Flash Drive), 14 Pages, 2017/09

An experimental study on the upward bubbly air-water flows in a vertical large-diameter square duct have been performed by using four-sensor probes. The four-sensor probe were applied in the local measurements at 3 axial positions along the flow direction to obtain interfacial area concentration, 3-D bubble velocity vector and bubble diameter. The obtained void fraction, interfacial area concentration, 3-D bubble velocity vector and bubble diameter provided valuable insight into the flow structure and will serve as a valuable database to develop the mechanistic models for interfacial area transport equation sources and sinks.

Journal Articles

Development of the severe accident evaluation method on second coolant leakages from the PHTS in a loop-type sodium-cooled fast reactor

Yamada, Fumiaki; Imaizumi, Yuya; Nishimura, Masahiro; Fukano, Yoshitaka; Arikawa, Mitsuhiro*

Proceedings of 25th International Conference on Nuclear Engineering (ICONE-25) (CD-ROM), 10 Pages, 2017/07

The loss-of-reactor-level (LORL) is one of the loss-of-heat-removal-system (LOHRS) of beyond-DBA (BDBA) severe accident. An evaluation method for the LORL which is caused by the coolant leakage in two positions of the primary heat transport system (PHTS) was developed for prototype JSFR which is loop-type sodium-cooled fast reactor. The secondary leakage in cold standby which occurred in different loop from that of the first leakage in rated power operation can lead LORL by excessive declining of the sodium level. Therefore, the sodium level behavior in RV was studied in a representative accident sequence by considering the sodium pumping up into RV, siphon-breaking to stop pumping out from RV and maintain the sodium level, and calculation programs for the transient sodium level in RV. The representative sequence with lowest sodium level was selected by considering combinations of possible leakage positions. As a result of the evaluation considering the countermeasures above, it was revealed that the LOHRS can be prevented by maintaining the sodium level for the operation of decay heat removal system, even in the leakages in two positions of PHTS which corresponds to BDBA.

Journal Articles

Methods and approaches to provide feedback from nuclear and covariance data adjustment for improvement of nuclear data files

Palmiotti, G.*; Salvatores, M.*; Yokoyama, Kenji; Ishikawa, Makoto

NEA/NSC/R(2016)6 (Internet), 42 Pages, 2017/05

Journal Articles

Determination of optimal vapor pressure data by the second and third law methods

Nakajima, Kunihisa

Mass Spectrometry (Internet), 5(2), p.S0055_1 - S0055_6, 2016/12

Though equilibrium vapor pressures are utilized to determine thermodynamic properties of not only gaseous species but also condensed phases, the obtained data often disagree by a factor of 100 and more. A new data analysis method is proposed using the so-called second and third law procedures to improve accuracy of vapor pressure measurements. It was found from examination of vapor pressures of cesium metaborate and silver that the analysis of the difference between the second and third law values can result in determination of an optimal data set. Since the new thermodynamic method does not require special techniques and or experiences in dealing with measured data, it is reliable and versatile to improve the accuracy of vapor pressure evaluation.

Journal Articles

Evaluation of globally- & locally-distributed erosion/cavitation damage by using laser ultrasonics

Wan, T.; Obayashi, Hironari; Sasa, Toshinobu

Kashika Joho Gakkai-Shi (USB Flash Drive), 36(Suppl.2), 8 Pages, 2016/10

JAEA Reports

Proceedings of the 2015 Symposium on Nuclear Data; November 19-20, 2015, Ibaraki Quantum Beam Research Center, Tokai-mura, Ibaraki, Japan

Iwamoto, Osamu; Sanami, Toshiya*; Kunieda, Satoshi; Koura, Hiroyuki; Nakamura, Shoji

JAEA-Conf 2016-004, 247 Pages, 2016/09

JAEA-Conf-2016-004.pdf:26.48MB

The 2015 Symposium on Nuclear Data was held at Ibaraki Quantum Beam Research Center, on November 19 and 20, 2015. The symposium was organized by the Nuclear Data Division of the Atomic Energy Society of Japan in cooperation with 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 two tutorials, "Theory of Few-Body Systems and Recent Topics" and "Use of Covariance Data 2015" and four oral sessions, "Recent Research Topics", "Progress of AIMAC Project", "Present Status of JENDL Evaluated Files", and "Nuclear Data Applications". In addition, recent research progress on experiments, evaluation, benchmark and application was presented in a poster session. Among 99 participants, all presentations and following discussions were very active and fruitful. This report consists of total 46 papers including 13 oral and 33 poster presentations.

Journal Articles

Validation of decay heat evaluation method based on FPGS cord for fast reactor spent MOX fuels

Usami, Shin; Kishimoto, Yasufumi; Taninaka, Hiroshi; Maeda, Shigetaka

Proceedings of International Conference on the Physics of Reactors; Unifying Theory and Experiments in the 21st Century (PHYSOR 2016) (USB Flash Drive), p.3263 - 3274, 2016/05

The present paper describes the validation of the new decay heat evaluation method using FPGS90 code with both the updated nuclear data library and the rational extent of uncertainty, by comparing the results of the decay heat measurement of the spent fuel subassemblies in Joyo MK-II core and by comparing with the calculation results of ORIGEN2.2 code. The calculated values of decay heat (C) by FPGS90 based on the JENDL-4.0 library were coincident with the measured ones (E) within the calculation uncertainties, and the C/E ranged from 1.01 to 0.93. FPGS90 evaluated the decay heat almost 3% larger than ORIGEN2.2, and it improved the C/E in comparison with the ORIGEN2.2 code. Furthermore, The C/E by FPGS90 based on the JENDL-4.0 library was improved than that based on the JENDL-3.2 library, and the contribution of the revision of reaction cross section library to the improvement was dominant rather than that of the decay data and fission yield data libraries.

Journal Articles

Gas-liquid bubbly flow structure in a vertical large-diameter square duct

Shen, X.*; Sun, Haomin; Deng, B.*; Hibiki, Takashi*; Nakamura, Hideo

Progress in Nuclear Energy, 89, p.140 - 158, 2016/05

 Times Cited Count:6 Percentile:17.95(Nuclear Science & Technology)

An experimental study was performed on the local structure of upward air-water two-phase flow in a vertical large diameter square duct by using a four-sensor probe. The four-sensor probe method classifying spherical and non-spherical bubbles was applied as a key measurement way to obtain local parameters such as 3-D bubble velocity vector, bubble diameter and interfacial area concentration. Both the local void fraction and interfacial area concentration indicated radial core-peak and wall-peak distributions at low and high liquid flow rates respectively. The 2 components of the bubble velocity vector in the cross-section revealed that there exists a rotating secondary flow in the octant symmetric triangular area and the magnitude of the rotating secondary flow increases with the liquid flow rate. Some of constitutive correlations of drift-flux model and interfacial area concentration are reviewed to study their predictabilities against the present data.

JAEA Reports

Proceedings of the 2014 Symposium on Nuclear Data; November 27-28, 2014, Conference hall, Hokkaido University, Sapporo Japan

Aikawa, Masayuki*; Iwamoto, Osamu; Ebata, Shuichiro*; Kunieda, Satoshi; Nakamura, Shoji; Koura, Hiroyuki

JAEA-Conf 2015-003, 332 Pages, 2016/03

JAEA-Conf-2015-003.pdf:30.22MB

The 2014 Symposium on Nuclear Data was held at Conference Hall, Hokkaido University, on November 27 and 28, 2014. The symposium was organized by the Nuclear Data Division of the Atomic Energy Society of Japan, Hokkaido Branch of the Atomic Energy Society of Japan, and Nuclear Reaction Data Centre, Faculty of Science, Hokkaido University in cooperation with Nuclear Science and Engineering Directorate of Japan Atomic Energy Agency. In the symposium, there were two tutorials, "Cross section measurement strategy for long lived fission product" and "Physics and Nuclear Data in Radiation Therapy" and four sessions, "A Neutron TOF Measurement Instrument desired by Nuclear Data Community", "Recent Topics", "Application of Nuclear Data", and "Nuclear Theory and Nuclear Data". In addition, recent research progress on experiments, evaluation, benchmark and application was presented in a poster session. Among 88 participants, all presentations and following discussions were very active and fruitful. This report consists of total 62 papers including 2 tutorials, 16 oral and 44 poster presentations.

Journal Articles

Medical application of radiohalogenated peptides; Synthesis and ${it in vitro}$ evaluation of F(${it p}$-$$^{131}$$I)KCCYSL for targeting HER2

Sasaki, Ichiro; Watanabe, Shigeki; Ohshima, Yasuhiro; Sugo, Yumi; Yamada, Keiichi*; Hanaoka, Hirofumi*; Ishioka, Noriko

Peptide Science 2015, p.243 - 246, 2016/03

Journal Articles

Measurements and evaluations of air dose rates around the Fukushima NPP site, 6; Status and issues on evaluation of individual doses due to external exposures

Saito, Kimiaki; Kurihara, Osamu*; Matsuda, Norihiro; Takahara, Shogo; Sato, Tetsuro*

Radioisotopes, 65(2), p.93 - 112, 2016/02

Late information is introduced on dose evaluation due to external exposures which employ an important role in the exposures due to the Fukushima accident. First, merits and demerits of the currently used two methods, that is the estimation based air dose rates and the measurements using personal dosimeters, are discussed indicating some basic data after a fundamental concept of external dose evaluation is provided. Next, main activities are summarized on external dose measurements and evaluations after the accident. Finally, a new trial on dose evaluation in introduced.

268 (Records 1-20 displayed on this page)