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JAEA Reports

Physical property investigation of gloves for glove boxes in nuclear fuel reprocessing plants; Physical properties of used gloves and estimation of its life-time

Yamamoto, Masahiko; Nishida, Naoki; Kobayashi, Daisuke; Nemoto, Ryo*; Hayashi, Hiroyuki*; Kitao, Takahiko; Kuno, Takehiko

JAEA-Technology 2023-004, 30 Pages, 2023/06

JAEA-Technology-2023-004.pdf:1.94MB

Glove-box gloves, that are used for handling nuclear fuel materials at the Tokai Reprocessing Plant (TRP) of the Japan Atomic Energy Agency, have an expiration date by internal rules. All gloves are replaced at a maximum of every 4-year. However, degrees of glove deterioration varies depending on its usage environment such as frequency, chemicals, and radiation dose. Therefore, physical properties such as tensile strength, elongation, hardness of gloves are measured and technical evaluation method for the glove life-time is established. It was found that gloves without any defects in its appearance have enough physical properties and satisfies the acceptance criteria values of new gloves. Thus, it was considered that the expired gloves could be used for total of 8-year, by adding 4-year of new glove life-time. In addition, the results of extrapolation by plotting the glove's physical properties versus the used years showed that the physical properties at 8-year is on the safer side than the reported physical properties of broken glove. Also, the data are not significantly different from the physical properties of the long-term storage glove (8 and 23 years). Based on these results, life-time of gloves at TRP is set to be 8-year. The frequency of glove inspections are not changed, and if any defects is found, the glove is promptly replaced. Thus, the risk related to glove usage is not increased. The cost of purchasing gloves, labor for glove replacement, and the amount of generated waste can be reduced by approximately 40%, respectively, resulting in more efficient and rationalized glove management.

Journal Articles

Investigation of physical properties of glove for glove-box and estimation of its life-time

Kobayashi, Daisuke; Yamamoto, Masahiko; Nishida, Naoki; Miyoshi, Ryuta; Nemoto, Ryo*; Hayashi, Hiroyuki*; Kato, Keisuke; Nishino, Saki; Kuno, Takehiko; Kitao, Takahiko; et al.

Nihon Hozen Gakkai Dai-18-Kai Gakujutsu Koenkai Yoshishu, p.237 - 240, 2022/07

All gloves attached to glove-box in Tokai Reprocessing Plant have a fixed expiration date and have to be replaced every 4-year. However, degrees of glove deterioration are different depending on its usage environment (frequency, chemicals, radiation, etc.), because of rubber products. Therefore, physical properties such as tensile strength, elongation, hardness of gloves are measured, and the life-time of gloves are estimated. As a result, gloves without any defects in its appearance have enough physical property for acceptance criteria of new glove. The extrapolated physical property of glove is sufficiently larger than the reported values of damaged glove. No deterioration in physical properties of gloves, that are periodically replaced without any defects in its appearance, is observed and the usable life-time of the glove is estimated to be 8 years.

JAEA Reports

Final report on feasibility study of Pu monitoring and solution measurement of high active liquid waste containing fission product at Reprocessing Facility

Sekine, Megumi; Matsuki, Takuya; Suzuki, Satoshi*; Tsutagi, Koichi; Nishida, Naoki; Kitao, Takahiko; Tomikawa, Hirofumi; Nakamura, Hironobu; LaFleur, A.*; Browne, M.*

JAEA-Technology 2019-023, 160 Pages, 2020/03

JAEA-Technology-2019-023.pdf:9.43MB

The International Atomic Energy Agency (IAEA) has proposed in its Research and Development plan (STR-385), the development of technology to enable real-time flow measurement of nuclear material as a part of an advanced approach to effective and efficient safeguards for reprocessing facilities. To address this, Japan Atomic Energy Agency (JAEA) has been tackling development of a new detector to enable monitoring of Pu in solutions with numerous FPs as a joint research program with U.S. DOE to cover whole reprocessing process. In this study, High Active Liquid Waste (HALW) Storage Facility in Tokai Reprocessing Plant was used as the test field. At first, the design information of HALW storage tank and radiation (type and intensity) were investigated to develop a Monte Carlo N-Particle Transport Code (MCNP) model. And then, dose rate distribution outside/ inside of the concrete cell where the HALW tank is located was measured to design new detectors and check MCNP model applicability. Using the newly designed detectors, gamma rays and neutron were continuously measured at the outside/ inside of the concrete cell to assess the radiation characteristics and to optimize detector position. Finally, the applicability for Pu monitoring technology was evaluated based on the simulation results and gamma-ray/neutron measurement results. We have found that there is possibility to monitor the change of Pu amount in solution by combination both of gamma-ray and neutron measurement. The results of this study suggested the applicability and capability of the Pu motoring to enhance safeguards for entire reprocessing facility which handles Pu with FP as a feasibility study. This is final report of this project.

Journal Articles

Security measures at nuclear fuel facilities, 2; Internal threat countermeasure in cyber-security

Kono, Soma; Yamada, Hiroyuki; Goto, Atsushi*; Yamazaki, Katsuyuki; Nakamura, Hironobu; Kitao, Takahiko

Nihon Kaku Busshitsu Kanri Gakkai Dai-39-Kai Nenji Taikai Rombunshu (Internet), 2 Pages, 2018/11

no abstracts in English

Journal Articles

Introduction and implementation of physical protection measures including trustworthiness program at Tokai Reprocessing Facilities

Nakamura, Hironobu; Kimura, Takashi; Yamazaki, Katsuyuki; Kitao, Takahiko; Tasaki, Takashi; Iida, Toru

Proceedings of International Conference on Physical Protection of Nuclear Material and Nuclear Facilities (Internet), 9 Pages, 2018/09

After the accident of Fukushima Daiichi Nuclear Power Station, to develop effective security measures based on the lesson learned from such crisis and to meet the IAEA Nuclear Security Recommendations (INFCIRC/225/Rev.5), NRA in Japan made a partial amendment of the regulations concerning the reprocessing activity in 2012. The Tokai reprocessing facility implemented all of those security measures by the end of March 2014. Those new measures help us to keep high degree of security level and contributed to our planned operations to reduce the potential risk of the plant. On the other hand, the trustworthiness program was newly introduced in 2016, based on the trustworthiness policy determined by NRA. The implementing entity of the program is JAEA for the Tokai Reprocessing Facility and is required for both the persons afford unescorted access to Category I and II, CAS/SAS, and the persons afford access to the sensitive information. Those who are involved this program will be judged before engaging the work whether they might act as insider to cause or assist radiological sabotage or unauthorized removal of nuclear material, or leak sensitive information. The program is expected as a measure against insider at reprocessing facilities, and is expected to be enforced around the autumn of 2017. As well as the establishment of security measures, the promoting nuclear security culture for all employees was a big challenge. The Tokai reprocessing facility have introduced several security culture activities, such as case study education of security events done by a small group and putting up the security culture poster and so on. This paper presents introduction and implementation with effectiveness of security measures in the Tokai reprocessing facilities and the future security measures applied to the reprocessing facilities are discussed.

Journal Articles

Feasibility study of technology for Pu solution monitoring including FP; Development of gamma spectra detector for high active liquid waste

Sekine, Megumi; Matsuki, Takuya; Tokoro, Hayate; Tsutagi, Koichi; Kitao, Takahiko; Nakamura, Hironobu; Tomikawa, Hirofumi

Proceedings of INMM 59th Annual Meeting (Internet), 10 Pages, 2018/07

In a reprocessing facility, it is necessary to develop a detector which can measure plutonium (Pu) content in the Pu solutions containing fission products (FP) in order to expand the application of Pu monitoring. In order to establish this technology, JAEA has studied a system measure $$gamma$$-rays was utilized since it applicable for Pu monitoring. Ce:GAGG (Ce:Gd$$_{3}$$Al$$_{2}$$Ga$$_{3}$$O$$_{12}$$) scintillator detector can measure a wide energy range in a high-dose environment and has reasonable resolution. $$gamma$$-ray measurements were performed inside of the concrete cell containing the High Active Liquid Waste tank at the Tokai reprocessing plant. In the spectra, the two significant peaks were measured by the GAGG above 800 keV and were considered to be from Eu-154. There $$gamma$$-ray measurements will be combined with previous neutron measurements and both will be compared to MCNP models for future Pu monitoring technology. This presentation will describe the detector selection, the design system, the results of $$gamma$$-ray spectral measurements and the applicability for Pu monitoring. This project has been carried out under the support of the Ministry of Education, Culture, Sports, Science and Technology (MEXT) of the Japanese government.

Journal Articles

Discussion of effective insider threat mitigation method at reprocessing plant

Nakamura, Hironobu; Kitao, Takahiko; Yamada, Hiroyuki; Kono, Soma; Kimura, Takashi; Tasaki, Takashi

Proceedings of INMM 59th Annual Meeting (Internet), 9 Pages, 2018/07

Journal Articles

Report on activities related to fostering nuclear security culture in Tokai Reprocessing Facility

Kitao, Takahiko; Takeuchi, Yoshikatsu; Kimura, Takashi; Kojima, Junji; Shioya, Satoshi; Tasaki, Takashi; Nakamura, Hironobu

Nihon Kaku Busshitsu Kanri Gakkai Dai-38-Kai Nenji Taikai Rombunshu (Internet), 9 Pages, 2018/04

In order to ensure and strengthen nuclear security measures, an active cultivation of nuclear security culture implemented by both entire organization and individual persons is vitally essential. Tokai reprocessing facility has conducted various activities such as case study education and training, yearly posters and patrolling the site by upper-level management that all employees hold a deep rooted belief that there is a credible insider and outsider threat, and that nuclear security is important. These activities are conducted in order to establish the foundation of beliefs and attitudes of effective nuclear security culture based on the IAEA guideline. This report introduces our activities fostering nuclear security culture in Tokai reprocessing facility that the evaluation and the continuous improvement of bidirectional activities by both top-down from multiple management levels and bottom-up from individual employee, and our challenges need to be worked on for the future.

Journal Articles

Maintenance experiences at analytical laboratory at the Tokai Reprocessing Plant

Suzuki, Hisanori; Nagayama, Tetsuya; Horigome, Kazushi; Ishibashi, Atsushi; Kitao, Takahiko; Surugaya, Naoki

Nihon Hozen Gakkai Dai-11-Kai Gakujutsu Koenkai Yoshishu, p.214 - 219, 2014/07

The Tokai Reprocessing Plant (TRP) is developing the technology to recover uranium and plutonium from spent nuclear fuel. There is an analytical laboratory which was built in 1978, as one of the most important facilities for process and material control analyses at the TRP. Samples taken from each process are analyzed by various analytical methods using hot cells, glove boxes and hume-hoods. A large number of maintenance work have been so far done and different types of experience have been accumulated. This paper describes our achievements in the maintenance activities at the analytical laboratory at the TRP.

Journal Articles

The Cause of corrosion occurred in a glove box filter casing and its repair technique

Mori, Eito; Yamamoto, Masahiko; Taguchi, Shigeo; Sato, Soichi; Kitao, Takahiko; Surugaya, Naoki

Nihon Hozen Gakkai Dai-11-Kai Gakujutsu Koenkai Yoshishu, p.132 - 138, 2014/07

The contamination of the radioactive material was observed on the filter casing surface of the glove box installed at the analytical laboratory in Tokai Reprocessing Plant. The cause of the contamination was investigated with visual inspection, penetrant testing and ultrasonic thickness measurement. It was found that a micro through-hole due to the corrosion of stainless-steel was generated in the glove box filter casing. The repair work of the filter casing was performed keeping the glove box negative pressure. The corrosion part of filter casing was replaced and newly fabricated casing was connected to the glove box with Tungsten Inert Gas welding method.

Journal Articles

Study of solvent degradation in reprocessing MOX spent fuel; Solvent degradation and its effect on Pu purification cycle

Kawaguchi, Yoshihito; Morimoto, Kazuyuki; Kitao, Takahiko; Oyama, Koichi; Omori, Eiichi

Nihon Genshiryoku Gakkai Wabun Rombunshi, 8(3), p.221 - 229, 2009/09

30% Tributyl phosphate (TBP)/n-dodecane is used on PUREX process in Tokai Reprocessing Plant (TRP). TBP is degraded to di-butyl phosphate (DBP), mono-butyl phosphate (MBP) etc. mainly caused by radiation, extracted element and hydrolysis. In this study, we studied TBP degradation kinetic equation, Pu concentration in high DBP concentration solution after stripping Pu from the solution by diluted HNO$$_{3}$$, DBP concentration in mixer-settler and effect for process while MOX spent fuel was reprocessed and operation was stopped with Pu loaded on solution for 20 days. As a result of this study, we obtained the equation of TBP degradation. Moreover, the maximum DBP concentration in mixer-settler while reprocessing MOX spent fuel was 91 ppm, DBP concentration while stopping operation was 2000 ppm and we found out there was nothing out of the ordinary on the process after the process was restarted.

Journal Articles

Determination of Plutonium in High Active Liquid Waste by Spectrophotometry using Neodymium as an Internal Standard for Safeguards Analysis

Taguchi, Shigeo; Surugaya, Naoki; Sato, Soichi; Kitao, Takahiko; Hina, Tetsuro; Toshiaki, Hiyama,

Dai-25-Kai Kaku Busshitsu Kanri Gakkai Nihon Shibu Nenji Taikai Rombunshu, p.120 - 127, 2004/00

For the determination of Pu in the high active liquid waste (HALW), isotope dilution mass spectrometry (IDMS) has been applied to verification analysis at Tokai Reprocessing Plant. IDMS has been considered as the most reliable analytical technique for accountability measurement of Pu in spent fuel reprocessing plant. However, it takes quite long time for inspector to obtain an analytical result because inspection sample has to be transported to safeguards analytical laboratory for off-site analysis. In order to overcome this disadvantage, a rapid verification analysis of Pu in HALW by conventional spectrophotometer using Nd as an internal standard was proposed to achieve on-site verification measurements. In this method, Nd standard is intended to be provided by International Atomic Energy Agency (IAEA) so that an inspector can independently control it not only as an internal standard but also as an authentication purpose. The validation analysis was carried out by comparing with IDMS. It was found that the values of Pu concentration obtained by proposed method were in good agreement with those obtained by IDMS. Therefore the proposed method can be expected for the application to the verification analysis.

Journal Articles

Determination of Plutonium in High Active Liquid Waste of Reprocessing Plant by Spectrophotometry using Neodymium as an Internal Standard

Surugaya, Naoki; Taguchi, Shigeo; Sato, Soichi; Kitao, Takahiko; Hina, Tetsuro; Hiyama, Toshiaki,

Proceedings of 45th INMM Annual Meeting, (112), p.33 - 34, 2004/00

A technique of measuring rapidly and correctly the concentration of Pu contained in the high radioactive liquid waste in a reprocessing plant has been developed. This method is based on spectrophotometry using Nd as an internal standard, and can be expected the application as measurement technology for the safeguards which has been utilizing the conventional method of isotope dilution mass spectrometry. This report describes the measurement principle and the result of the examination which used a real sample.

Journal Articles

Determination of Plutonium in High Active Liquid Waste of Reprocessing Plant by Spectrophotometry using Neodymium as an Internal Standard

Surugaya, Naoki; Taguchi, Shigeo; Sato, Soichi; Hina, Tetsuro; Toshiaki, Hiyama,; Kitao, Takahiko

Proceedings of 45th INMM Annual Meeting, CD-ROM, 8p., 8 Pages, 2004/00

A rapid verification technique with conventional spectrophotometer has been developed to achieve on-site safeguards measurements in which neodymium as an internal standard was chosen to determine the plutonium concentration in high radioactive liquid waste.This method will provide the on-site analytical capabilities as it allows rapid and simple analyses at Tokai Reprocessing Plant.

JAEA Reports

Confirmation of the availability of an analytical technique, Pu(VI) spectrophotometry for HALW; Technical Support for the Joint IAEA/Japan On-site Analytical Laboratory at the Rokkasho Reprocessing Plant (JASPAS JU-01-01)

Kitao, Takahiko; Sato, Soichi; Kuno, Takehiko; Keiji, Yamada,; Watahiki, Masaru; Kamata, Masayuki

JNC TN8410 2003-014, 29 Pages, 2003/11

JNC-TN8410-2003-014.pdf:1.82MB

The Agency requested the Tokai Reprocessing Plant(TRP) to confirm the applicability of three kinds of analytical procedure for Pu(VI) spectrophotometry in On-Site Analytical Laboratory (OSL) at Rokkasho, in order to obtain accurate plutonium(Pu) concentration in High Active Liquid Waste (HALW). Three analytical procedures, (1) Calibration method, (2) Nd internal standard method and (3) Reduction method, were tested. The measurement sample was prepared by adding the known amount of plutonium in the actual HALW after removing original Pu by solid extraction. We measured the Pu concentration in the sample by three methods and calculated the accuracy and precision. The results of each method are summarized as follows:(1) Calibration method Plutonium concentration calculated by the calibration method agreed with that by adjusted concentration. (2) Nd internal standard method Accurate results were obtained by this method. The error of pretreatment, especially dilution, has not influenced on the Pu measurements. (3) Reduction method The measured Pu concentrations were higher than those by adjusted. From the comparison with these results, the calibration method is the most simple and rapid in the three methods. Analysis time was within 1 hour including sample preparation. The detection limit, with the calibration method, was 1.3 mgPu/L in the actual HALW measurements.

Journal Articles

Determination of Plutonium in High Active Liquid Waste by Spectrophotometry using Dysprosium as an Internal Standard

Kitao, Takahiko; Jitsukata, Shu*; Sato, Soichi; Ikeda, Hisashi ; Atsushi, Ishibashi,; Surugaya, Naoki

SYMPOSIUM ON SAFEGUARDS AND NUCLEAR MATERIAL MANAGEMENT, 0 Pages, 2001/00

None

Oral presentation

The Dose-reduction activity of the lens of the eye at Tokai Reprocessing Plant

Nishino, Saki; Nemoto, Ryo*; Hayashi, Hiroyuki*; Kobayashi, Daisuke; Isomae, Hidemi; Sakuma, Shuhei; Takimoto, Misaki; Okuyama, Shun; Unno, Motoyoshi; Kitao, Takahiko

no journal, , 

At the JAEA Tokai Reprocessing facility, especially workers engaged in Plutonium Conversion Development Facility (PCDF) are required strict radiation control due to working environment handling various nuclear material including plutonium (Pu) at short range. Because the equivalent dose limit of the lens of the eye stipulated by Japanese regulations has been revised downwards, we reassessed personal dose equivalent focusing on the lens of the worker's eye. The reassessment results indicate that wearing the appropriate radiation protection glasses is necessary for some workers who handle Pu including waste material in PCDF. Radiation management using protective glasses has started under revised radiation control plan.

Oral presentation

Japan - U.S. cooperation on design and development of the advanced hulls measurement and monitoring system for decommissioning of the Tokai Reprocessing Plant

Kitao, Takahiko; Shirafuji, Masaya; Sano, Kyohei; Watanabe, Kazuki; Horiuchi, Masakazu; Kato, Akane; Conner, J.*; LaFeur, A.*; Watson, M.*

no journal, , 

Oral presentation

NDA application in Reprocessing Facility waste drum assay

Kitao, Takahiko

no journal, , 

The explanation regarding the NDA application in reprocessing facility in NDA Follow up course.

Oral presentation

Lessons learned / best practices on determination of decommissioned status; Operator's point of view

Nakamura, Hironobu; Kitao, Takahiko; Shimizu, Yasuyuki; Takeda, Seiichi; Yamaguchi, Katsuhiro*

no journal, , 

In order to determine the decommissioned status in the IAEA safeguards, JAEA attends the expert meeting held in IAEA to share the lessons learned and/or best practices. In the domestic examples, we can share a few examples in the decommissioning of experimental reactors, unfortunately, since there is no example in the bulk handling facilities (the facility which amount of nuclear material is determined by the measurement) such as reprocessing, MOX fabrication and centrifuge enrichment, based on the situation of nuclear material and dismantling of important process equipment (i.e. no reprocessing capability) in the decommissioning plan, after the confirmations that remaining nuclear materials is recovered and transferred to other facilities, and no process capability is established, are completed, it is concluded that it is necessary to terminate safeguards and nuclear material accountancy. In this report, we summarized the proposals as subjects such as change of material balance area or implementation of material balance evaluation by the decommissioning. we hope that the proposals is helped to determine the decommissioned status in the IAEA safeguards.

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