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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

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

Nippon 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

Maintenance experiences at analytical laboratory at the Tokai Reprocessing Plant

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

Nippon 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

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

Nippon 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 Nippon 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; Hisashi, Ikeda,; Atsushi, Ishibashi,; Surugaya, Naoki

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

None

Oral presentation

Determination of neptunium in reprocessing process, 3; Determination of neptunium by $$gamma$$ spectrometry in nitric acid media

Kitao, Takahiko; Nemoto, Hirokazu*; Shoji, Kazuhiro; Yamada, Keiji; Kurakata, Koichiro; Sato, Soichi

no journal, , 

no abstracts in English

Oral presentation

Determination of neptunium of Tokai reprocessing plant; Determination of neptunium by $$gamma$$ spectrometry in nitric acid media

Kitao, Takahiko; Nemoto, Hirokazu*; Yamada, Keiji; Sakai, Toshio

no journal, , 

no abstracts in English

Oral presentation

Determination of neptunium in Tokai reprocessing plant; Determination of neptunium by $$gamma$$ spectrometry in nitric acid media

Kitao, Takahiko; Nemoto, Hirokazu*; Yamada, Keiji; Sakai, Toshio

no journal, , 

no abstracts in English

Oral presentation

MOX reprocessing at TRP, 6; Study of solvent degradation

Hoshi, Takahiro; Kawaguchi, Yoshihito; Kitao, Takahiko; Oyama, Koichi; Morimoto, Kazuyuki; Kanamori, Sadamu; Omori, Eiichi

no journal, , 

For reprocessing nuclear spent fuel, in future, used for plutonium-thermal and fast-breeding reactor, density of DBP in extraction solvent on reprocessing Fugen MOX Type B fuel was measured. And we formulated an equation for increased density of DBP to estimate density of DBP in extraction cycle.

Oral presentation

Determination of uranium by flow injection analysis (FIA) in reprocessing process

Yokosuka, Keisuke*; Suwa, Toshio; Kitao, Takahiko; Yamada, Keiji; Sakai, Toshio

no journal, , 

no abstracts in English

Oral presentation

MOX reprocessing at TRP, 4; Control test of Neptunium extraction

Kawakami, Yoshiyuki; Nagaoka, Shinichi; Kitao, Takahiko; Morimoto, Kazuyuki; Obu, Tomoyuki; Kanamori, Sadamu; Omori, Eiichi

no journal, , 

We are trying to research how acidity and temperature influences Np behavior at extraction process in Tokai Reprocessing Plant. So we varied acidity and warmed up solution within the limit of operating parameter for second extraction cycle, and measured Np extracted.

Oral presentation

Control test of neptunium extraction at Tokai reprocessing plant

Nagaoka, Shinichi; Morimoto, Kazuyuki; Kitao, Takahiko; Obu, Tomoyuki; Kanamori, Sadamu; Omori, Eiichi

no journal, , 

40$$sim$$50% of neptunium (Np) was distributed to product stream in Tokai Reprocessing Plant (TRP) at present. We tried to increase acidity of second extraction cycle within available operating parameter, and by measuring neptunium concentration at outlet stage in second extraction cycle, we verified that 60$$sim$$70% of neptunium was distributed to product stream. Also we warmed up solutions in contactors of second extraction cycle within available operating parameter to make sure oxidation of neptunium on actual process, and we verified that 70% of neptunium was distributed to product stream. We confirmed that increasing acidity and warming up solutions was effective for Pu-U-Np co-extraction on the engineering scale reprocessing facility.

Oral presentation

Simultaneous determination of U(IV) and U(VI) in uranium nitrate solutions by differential pulse voltammetry

Masui, Kenji; Kitao, Takahiko; Inada, Satoshi; Yamada, Keiji; Watahiki, Masaru

no journal, , 

no abstracts in English

27 (Records 1-20 displayed on this page)