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JAEA Reports

Activities of Working Group on Verification of PASCAL; Fiscal years 2016 and 2017

Li, Y.; Hirota, Takatoshi*; Itabashi, Yu*; Yamamoto, Masato*; Kanto, Yasuhiro*; Suzuki, Masahide*; Miyamoto, Yuhei*

JAEA-Review 2020-011, 130 Pages, 2020/09

JAEA-Review-2020-011.pdf:9.31MB

For the improvement of the structural integrity assessment methodology on reactor pressure vessels (RPVs), the probabilistic fracture mechanics (PFM) analysis code PASCAL has been developed and improved in Japan Atomic Energy Agency based on the latest knowledge. The PASCAL code evaluates the failure probabilities and frequencies of Japanese RPVs under transient events such as pressure thermal shock considering neutron irradiation embrittlement. In order to confirm the reliability of the PASCAL as a domestic standard code and to promote the application of PFM on the domestic structural integrity assessments of RPVs, it is important to perform verification activities, and summarize the verification processes and results as a document. On the basis of these backgrounds, we established a working group, composed of experts on this field besides the developers, on the verification of the PASCAL module and the source program of PASCAL was released to the members of working group. This report summarizes the activities of the working group on the verification of PASCAL in FY2016 and FY2017.

Journal Articles

A Chemiluminescence sensor with signal amplification based on a self-immolative reaction for the detection of fluoride ion at low concentrations

Hisamatsu, Shugo; Suzuki, Shinichi; Komoto, Shigeo*; Kishikawa, Keiki*; Yamamoto, Yusuke*; Motokawa, Ryuhei; Yaita, Tsuyoshi

Tetrahedron, 73(27-28), p.3993 - 3998, 2017/07

 Times Cited Count:11 Percentile:59.46(Chemistry, Organic)

Journal Articles

Mesoporous silica particles as topologically crosslinking fillers for poly($$N$$-isopropylacrylamide) hydrogels

Miyamoto, Nobuyoshi*; Shimasaki, Kotaro*; Yamamoto, Kosuke*; Shintate, Morio*; Kamachi, Yuichiro*; Bastakoti, B. P.*; Suzuki, Norihiro*; Motokawa, Ryuhei; Yamauchi, Yusuke*

Chemistry; A European Journal, 20(46), p.14955 - 14958, 2014/11

 Times Cited Count:16 Percentile:51.93(Chemistry, Multidisciplinary)

Journal Articles

Size and composition analyses of colloids in deep granitic groundwater using microfiltration/ultrafiltration while maintaining in situ hydrochemical conditions

Aosai, Daisuke*; Yamamoto, Yuhei*; Mizuno, Takashi; Ishigami, Toru*; Matsuyama, Hideto*

Colloids and Surfaces A; Physicochemical and Engineering Aspects, 461, p.279 - 286, 2014/11

AA2014-0448.pdf:0.9MB

 Times Cited Count:9 Percentile:27.22(Chemistry, Physical)

In studies of colloids in deep groundwater, a serious problem exists because the properties of the colloids are influenced by changes in the chemistry of groundwater upon exposure to the atmosphere and pressure release during sampling. Then, ultrafiltration technique, while maintaining in situ hydrochemical conditions was developed. As the result of the investigation using the method at the Mizunami underground Research Laboratory (MIU), different types of colloids consisting of inorganic and organic substances were observed and complex formation between the colloids and REEs was suggested. Furthermore, characteristic partitioning of REEs depending on colloids size was observed in complex natural environments without chemical disturbance. The current findings are useful for understanding migration of radionuclides.

Journal Articles

Increment of the machine protection system in J-PARC rapid cycling synchrotron

Yamamoto, Kazami; Kawase, Masato; Iwama, Yuhei; Fukuta, Shimpei; Kato, Yuko; Ouchi, Nobuo; Meigo, Shinichiro; Oi, Motoki; Kamikubota, Norihiko*

Proceedings of 11th Annual Meeting of Particle Accelerator Society of Japan (Internet), p.771 - 774, 2014/10

The radiation leak accident happened in the hadron experimental hall of J-PARC on May 23, 2013. The accident was caused by a target sublimation due to an unanticipated beam from the 50 GeV main ring (MR). To detect and prevent the radiation leakage in all facilities of J-PARC, we improve the machine protection system (MPS). In the J-PARC 3GeV synchrotron (Rapid Cycling Synchrotron, RCS), a monitoring system of an abnormal state of the extraction beam to the mercury target of material life science experiment facility (MLF) were prepared. The radiation level of the gas in the tunnel were able to always observed by connecting radiation safety system and accelerator control system. The dump temperature was included in the MPS. We also developed new interlock system that can stop the beam immediately when the beam current exceed the limit.

Journal Articles

Beam loss monitor system of the Rapid Cycling Synchrotron of Japan Proton Accelerator Research Complex

Yamamoto, Kazami; Hayashi, Naoki; Hatakeyama, Shuichiro; Saeki, Riuji; Iwama, Yuhei

Proceedings of 10th Annual Meeting of Particle Accelerator Society of Japan (Internet), p.1060 - 1064, 2014/06

The 3 GeV Rapid Cycling Synchrotron (RCS) of the Japan Proton AcceleratoR Complex (J-PARC) provides more than 300 kW beam to the Material and Life Science Facility (MLF) and the Main Ring (MR). In such high intensity hadron accelerator, the lost protons that are a fraction of the beam less than 0.1% cause many problems. Those particles bring about a serious radioactivation and a malfunction of the accelerator components. Therefore, the beam loss monitor (BLM) is one of the most important equipment to observe the state of the beam during operation, and to keep a steady operation. Moreover, if we set operation parameters of BLM adequately, it can detect the beam loss that is 10$$^{-6}$$ fraction of the beam. Thus it enables fine-tuning of the accelerator. In the J-PARC RCS, a proportional counter and a plastic scintillation counter are used for the beam commission and the stable operation as BLM. We report present status of the BLM system in J-PARC RCS.

Journal Articles

Sorption of Eu(III) on granite; EPMA, LA-ICP-MS, batch and modeling studies

Fukushi, Keisuke*; Hasegawa, Yusuke*; Maeda, Koshi*; Aoi, Yusuke*; Tamura, Akihiro*; Arai, Shoji*; Yamamoto, Yuhei*; Aosai, Daisuke*; Mizuno, Takashi

Environmental Science & Technology, 47(22), p.12811 - 12818, 2013/11

 Times Cited Count:19 Percentile:55.01(Engineering, Environmental)

Eu(III) sorption on granite was examined by the combined microscopic and macroscopic approaches. Polished thin sections of the granite were reacted with solutions containing 10 $$mu$$M of Eu(III) and analyzed using EPMA and LA-ICP-MS. The Eu enrichment up to 6 wt.% was observed on most of the biotite grains. The Eu-enriched parts commonly lose K, which is the interlayer cation of biotite, indicating that the sorption mode is cation exchange in the interlayer. Batch Eu(III) sorption experiments on granite and biotite powders were conducted. The macroscopic sorption behavior of biotite was consistent with that of granite. The obtained sorption edges can be reproduced reasonably by the modeling considering single-site cation exchange reactions. Granite is complex mineral assemblages. However, the combined microscopic and macroscopic approaches revealed that elementary reactions by single phase can be representative for the bulk sorption reaction in complex mineral assemblages.

Journal Articles

Hydrochemical changes associated with construction of Mizunami Underground Research Laboratory

Mizuno, Takashi; Aosai, Daisuke; Shingu, Shinya; Hagiwara, Hiroki; Yamamoto, Yuhei; Fukuda, Akari

Nihon Genshiryoku Gakkai Wabun Rombunshi, 12(1), p.89 - 102, 2013/03

no abstracts in English

Journal Articles

Abundances of rare earth elements in crude oils and their partitions in water

Nakada, Ryoichi*; Takahashi, Yoshio*; Zheng, G.*; Yamamoto, Yuhei; Shimizu, Hiroshi*

Geochemical Journal, 44(5), p.411 - 418, 2010/10

 Times Cited Count:24 Percentile:59.73(Geochemistry & Geophysics)

Patterns of the entire range of REE in crude oils and coexisting water, collected from mud volcanoes in Xinjiang Province of China, are reported here for the first time. Crude oils show light REE enriched patterns with flat or depleted patterns in heavy REE, when normalized to chondrite. The REE concentrations in crude oils are larger than those in coexisting water by a factor of more than one hundred. Considering the hydrophobicity of oil and the high ionic characteristics of REE, it is strongly suggested that REE form complexes with ligands present in the crude oils. Based on the $$^{13}$$C NMR spectroscopy, it is found that small amounts of phenol and carboxyl groups are contained in the crude oil samples, which could possibly provide complexing sites for REE. REE patterns of crude oils are similar to those of coexisting mud samples collected from the same mud volcanoes, which suggests that the REE in crude oils are derived from rocks and sediments where crude oils were generated.

Journal Articles

EXAFS study on the cause of enrichment of heavy REEs on bacterial cell surfaces

Takahashi, Yoshio*; Yamamoto, Mika*; Yamamoto, Yuhei; Tanaka, Kazuya

Geochimica et Cosmochimica Acta, 74(19), p.5443 - 5462, 2010/10

 Times Cited Count:64 Percentile:87.08(Geochemistry & Geophysics)

Among various natural samples, rare earth element (REE) pattern of bacteria exhibits anomalous enrichment at heavy REE (HREE) part, which can be a signature of bacteria-related materials. In this study, REE binding site on the cell surface of a Gram-positive bacterium (Bacillus subtilis) responsible for the HREE enrichment has been identified by extended X-ray absorption fine structure (EXAFS) coupled with the variation of REE distribution pattern. EXAFS showed that (1) HREE is bound to multiple phosphate site at lower REE-bacteria ratio (=[REE]/[bac]), but the fraction coordinated to carboxylate increased as the increase in the ratio and (2) the binding sites of light and middle REE change from phosphate with lesser coordination number to carboxylate site as the [REE]/[bac] ratio increases. On the other hand, the enrichment of HREE in the REE distribution patterns of bacteria was less marked as the increase in the [REE]/[bac] ratio. This result is consistent with the EXAFS results, since REE pattern of multiple phosphate site exhibits monotonous increase for HREE, while phosphate with lesser coordination number and carboxylate site have maxima around Sm. Based on these results, it was clear that phosphate site is more stable than carboxylate site as the binding site for REE. The average bond lengths between REE and oxygen were compared among various REE sorbed on bacteria, showing that the bond length was much shorter for HREE than those extrapolated from the trend between La and Dy due to the selective binding of HREE to the multiple phosphate site. Based on the results, it is thought that materials having such phosphate site can induce anomalous HREE enrichment in natural systems. Compared with other possible host phases of REE such as metal oxides and humic substances, the multiple phosphate site is unique to bacteria and bacteria-related materials such as biofilm and microbial mats, which leads to the potential of REE pattern as a biomarker in natural samples.

Journal Articles

Evaluation of behavior of rare earth elements based on determination of chemical state in groundwater in granite

Yamamoto, Yuhei; Aosai, Daisuke; Mizuno, Takashi

Proceedings of 13th International Conference on Environmental Remediation and Radioactive Waste Management (ICEM 2010) (CD-ROM), p.203 - 212, 2010/10

Journal Articles

Development of new ultrafiltration techniques maintaining in-situ hydrochemical conditions for colloidal study

Aosai, Daisuke; Yamamoto, Yuhei; Mizuno, Takashi

Proceedings of 13th International Conference on Environmental Remediation and Radioactive Waste Management (ICEM 2010) (CD-ROM), p.213 - 220, 2010/10

Size distribution of elements in groundwater is one of the most important information for understanding behavior of elements in deep underground environment. Size distribution is controlled mainly by groundwater physico-chemical parameters. Because the alteration of their physico-chemical states in groundwater cause changes of size distribution, systematic methodologies of ultrafiltration maintaining in-situ pressurized and anaerobic conditions is required. In this study, instrument for ultrafiltration maintaining in-situ pressurized/anaerobic conditions was developed and size distribution analysis was also conducted. The instrument developed in this study for consisted of passivated SUS materials is designed as to keep inner groundwater sample under a pressurized/anaerobic condition. Ultrafiltration was conducted at a borehole drilled from sub-stage at a depth of 200 m at the Mizunami Underground Research Laboratory site. The results obtained here indicate that ultrafiltration method is available for collection of filtered groundwater and passivation is an essential treatment before ultrafiltration.

Oral presentation

Size distribution of trace metal elements in groundwater in granite

Yamamoto, Yuhei; Aosai, Daisuke; Mizuno, Takashi

no journal, , 

no abstracts in English

Oral presentation

Hydrochemical investigations at Mizunami Underground Research Laboratory; Consideration for validation of the result of 1st phase investigations

Mizuno, Takashi; Sai, Masataka; Hagiwara, Hiroki; Aosai, Daisuke; Yamamoto, Yuhei

no journal, , 

no abstracts in English

Oral presentation

Mizunami Underground Research Project; Investigation of groundwater chemistry

Hagiwara, Hiroki; Mizuno, Takashi; Sai, Masataka; Aosai, Daisuke; Yamamoto, Yuhei

no journal, , 

no abstracts in English

Oral presentation

Development of sample collection and chemical analysis techniques for colloid in groundwater

Yamamoto, Yuhei; Aosai, Daisuke; Mizuno, Takashi

no journal, , 

no abstracts in English

Oral presentation

A Study of colloids in deep groundwater using spectroscopic analysis

Yamamoto, Yuhei; Aosai, Daisuke; Mizuno, Takashi; Watanabe, Katsuaki*; Kogure, Toshihiro*; Suzuki, Yohei*

no journal, , 

no abstracts in English

Oral presentation

JAEA/AIST collaborative research project; Development and evaluation of investigation methodology to quantify microbial influences on the deep hydrogeochemical properties

Fukuda, Akari; Mizuno, Takashi; Aosai, Daisuke; Hagiwara, Hiroki; Yamamoto, Yuhei; Shingu, Shinya; Ito, Kazumasa*; Suzuki, Yohei*; Kozuka, Mariko*; Konno, Yuta*

no journal, , 

no abstracts in English

Oral presentation

Mizunami Underground Research Laboratory project; Hydrochemical study

Mizuno, Takashi; Hagiwara, Hiroki; Aosai, Daisuke; Shingu, Shinya; Yamamoto, Yuhei; Fukuda, Akari

no journal, , 

no abstracts in English

Oral presentation

Development of the method for collection and analysis of colloids in groundwater

Yamamoto, Yuhei; Aosai, Daisuke; Mizuno, Takashi

no journal, , 

no abstracts in English

43 (Records 1-20 displayed on this page)