Yoshinaka, Kazuyuki; Shimizu, Kazuyuki; Sugiyama, Takayuki
JAEA-Review 2021-008, 112 Pages, 2021/07
We had drastically been improving quality assurance system for Tokai Reprocessing Plant (TRP), through applying new regulatory requirements, giving up ISO certification from FY2012 to 2019. In revising QA system, it is obviously necessary to satisfy the regulatory requirements, but it is important to continuously improve the QA system considering effectiveness to safety performance based on earlier experiences. In this report, the background of QA system revision, interpretation and thinking way of conformation and application to new regulation and "Application Guide to Quality Assurance Code for Safety in Nuclear Power Plants (JEAC 4111)" to TRP, issues considered. And matters that require attention for future QA activities are described. Key points are "in work processes planning, relationship with other sections and responsibility boundaries should be clearly defined with such as flow chart", "to manage decision-making processes is important, including input information, judgment criteria and so on", "concerning process monitoring and measurement, not only focusing on scheduling but also viewpoints toward conditions of facilities/systems, conformance to regulatory requirements and process improvement are necessary", and "in documentation, matching for existing system, clear relation to other fundamental documents are necessary".
Taguchi, Shigeo; Taguchi, Katsuya; Makino, Risa; Yamanaka, Atsushi; Suzuki, Kazuyuki; Takano, Masato; Koshino, Katsuhiko; Ishida, Michihiko; Nakano, Takafumi; Yamaguchi, Toshiya
Nihon Hozen Gakkai Dai-17-Kai Gakujutsu Koenkai Yoshishu, p.499 - 502, 2021/07
In 2018, Tokai Reprocessing Plan (TRP) shifted to the decommissioning stage. In order to proceed with steady decommissioning work, TRP effort to enhance project management function. This paper describes the establishment and role of the Decommissioning Project Management Office, effectiveness of applying the project management tool and its utilization concept, and the method of materialize the equipment dismantling plan.
Goto, Sho; Aoki, Kenji; Morimoto, Kenji; Tsuboi, Masatoshi; Isozaki, Naohiko; Furukawa, Ryuichi; Kitagawa, Osamu; Fukaya, Yasuhiro*
Nihon Hozen Gakkai Dai-17-Kai Gakujutsu Koenkai Yoshishu, p.517 - 520, 2021/07
no abstracts in English
Hoken Butsuri (Internet), 56(1), p.17 - 25, 2021/03
The Tokai Reprocessing Plant is the first reprocessing plant in Japan which started hot test in 1977, and had reprocessed 1140 tons of spent nuclear fuel by May 2007. The gaseous and liquid radioactive wastes has been discharged to the environment. Since iodine-129 (I) is one of the most important nuclides for environmental impact assessment. Therefore, I in the exhaust and effluent has been controlled, and a precise analysis method of I in the environmental samples was developed, and the concentration of 129I in the environment was investigated. This report presents an overview of these activities. Not limited to I on reprocessing facilities, it is essential for nuclear operators to reduce the amount released to the environment in the spirit of ALARA, and to continuously develop the further upgrading environmental monitoring methods and evaluation methods in order to foster a sense of safety and security among residents living in the vicinity of the facilities.
Yamamoto, Masahiko; Do, V. K.; Taguchi, Shigeo; Kuno, Takehiko; Takamura, Yuzuru*
Journal of Radioanalytical and Nuclear Chemistry, 327(1), p.433 - 444, 2021/01
A simple, practical, and reliable analytical method for determination of Na, K, Ca, Sr, and Ba by liquid electrode plasma optical emission spectrometry is developed. Appropriate emission lines for quantification, interferences from co-existing elements, and effect of measurement conditions with cell damage have been investigated. The spike and recovery tests using actual sample have been performed for method validation, and negligible sample matrix effect has been observed. Consequently, the method is successfully applied to several radioactive wastes. The obtained data have been agreed well with data from computer calculation and inductively coupled plasma optical emission spectrometry within 10% difference.
Yamamoto, Masahiko; Karo, Yoshinori*; Kodaka, Noriyasu; Kuno, Takehiko
JAEA-Technology 2019-014, 68 Pages, 2019/10
Analytical devices like syringe pump, electric burette, fraction collector, and electric valve have been controlled by the program written with Visual Basic for Applications (VBA Macro) to automate the column separation of radioactive sample measurement. It is found that VBA Macro can control each device. Therefore, automatic conditioning and separation equipment were made by combining each device and sequentially controlling with the program. The automation conditioning equipment can repeatedly perform conditioning operation with maximum of 8 columns. The automation separation equipment can separate and recover Sr in simulated highly active liquid waste by using Eichrom Technologies Sr resin. It is found that the developed automation method, using commercially available VBA Macro, is effective to reduce labor work, operator's radiation exposure, and to prevent operational error of analysis, together with reducing the cost of automation.
Yamamoto, Masahiko; Taguchi, Shigeo; Do, V. K.; Kuno, Takehiko; Surugaya, Naoki
Applied Radiation and Isotopes, 152, p.37 - 44, 2019/10
An online measurement system using an alpha liquid scintillation counter (-LSC) coupled to microchip solvent extraction has been developed. A flow-through cell of -LSC has been prepared by packing PTFE tube into glass tube to combine microchip. Two-phase flow in microchannel has been stabilized by using coiled tube. The Pu in organic phase has been mixed with scintillation cocktail by T-junction connectors. The system separates and detects Pu by online with detection limit of 6.5 Bq/mL, generating only L-level wastes.
Goto, Yuichi; Inada, Satoshi; Kuno, Takehiko; Mori, Eito*
Nihon Hozen Gakkai Dai-16-Kai Gakujutsu Koenkai Yoshishu, p.221 - 224, 2019/07
Test equipment, containers, and analytical wastes, generated by experiments using spent fuel pieces in hot cell of Operation Testing Laboratory and by analysis of highly active liquid wastes in hot analytical cell line of Tokai Reprocessing Plant, are treated as highly radioactive solid wastes. These wastes are stored in specific shielded containers called waste cask and then transport to the storage facility. The treatment of these highly radioactive solid wastes have been carried out for 40 years with upgrading waste taking out system and transportation device. As a results, automation of several procedures have been achieved utilizing conventional equipment, and work efficiency and safety have been improved.
Isozaki, Naohiko; Morimoto, Kenji; Furukawa, Ryuichi; Tsuboi, Masatoshi; Yada, Yuji; Miyoshi, Ryuta; Uchida, Toyomi; Ikezawa, Kazumi*; Kurosawa, Kenji*
Nihon Hozen Gakkai Dai-16-Kai Gakujutsu Koenkai Yoshishu, p.225 - 228, 2019/07
Highly active liquid waste, which is generated by the reprocessing of spent nuclear fuel, is stored in storage tank of Tokai Reprocessing Plant until it is vitrified. The waste solution in the tank is periodically agitated to avoid the precipitation of insoluble residues during the storage. Three way valves and ball valves have been located at the tank for agitation. Radiation dose rate at the valve location is high and operator's radiation exposure become a problem. Therefore, measures to reduce radiation exposure are performed and reported in this presentation.
Yamamoto, Masahiko; Do, V. K.; Taguchi, Shigeo; Kuno, Takehiko; Takamura, Yuzuru*
Spectrochimica Acta, Part B, 155, p.134 - 140, 2019/05
The emission spectra of technetium (Tc) by liquid electrode plasma optical emission spectrometry have been investigated in this study. From the spectra, 52 emission peaks of Tc were observed in the 250-500 nm wavelength range. All peaks were assigned to the neutral state or singly ionized state. The relative intensities of these peaks were similar to those excited by an electric spark. The strongest intensity peaks were found at 254.3 nm, 261.0 nm, and 264.7 nm. Spectral interferences of coexisting elements in highly active liquid waste of reprocessing stream on those three strongest peaks were investigated using simulated sample. No spectral interferences were observed around the 264.7 nm Tc peak. Therefore, analytical performance using 264.7 nm peak was evaluated. The detection limit, estimated on standard and blank samples in 0.4 M nitric acid, was 1.9 mg/L. The relative standard deviation of Tc standard sample (12.0 mg/L) was 3.8% (N = 5, 1).
Sato, Fuminori; Matsushima, Ryotatsu; Ito, Yoshiyuki
QST-M-16; QST Takasaki Annual Report 2017, P. 60, 2019/03
Hydrogen gas generation by -radiation from cement solidified products loading low-level radioactive liquid waste generated at LWTF in Tokai Reprocessing Facility was studied.
Taguchi, Shigeo; Miyauchi, Hironari*; Horigome, Kazushi; Yamamoto, Masahiko; Kuno, Takehiko
Bunseki Kagaku, 67(11), p.681 - 686, 2018/11
In thermal ionization mass spectrometry, de-gassing is one of the important treatments to release impurities of filaments and to minimize the influence of background. In this work, the effect of the surface change in the tungsten filament induced by the conductively heating treatment on uranium isotopic (U/U) measurement has been investigated. It was found that the conductively heating treatment of the filament has the effect of smoothing the surface of the filament and also has the effect of improving the deposition of the sample on the filament surface. As a result of either these effects, the precision of uranium isotopic (U/U) measurement was improved.
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
Yamamoto, Masahiko; Taguchi, Shigeo; Horigome, Kazushi; Kuno, Takehiko
Proceedings of IAEA Symposium on International Safeguards; Building Future Safeguards Capabilities (Internet), 8 Pages, 2018/11
In this study, the single-column extraction chromatographic separation has been developed for analysis of U and Pu in highly active liquid waste by isotope dilution mass spectrometry (IDMS). The commercially available TEVA resin is selected as an extraction chromatography resin. The U is chromatographically separated from fission products (FP) elements by nitric acid while Pu(IV) is adsorbed on the resin. After that, Pu is eluted by reducing to Pu(III). The method has been successfully achieved the separation with yielding the enough recovery and sufficient decontamination factors for subsequent IDMS analysis. The column dose rate after the FP removal is decreased to the background. The analytical results obtained by the developed method are in a good agreement with those of the conventional method. It provides simple and rapid separation and expected that the method can be applied to join IAEA/Japan on-site analytical laboratory.
Matsushima, Ryotatsu; Sato, Fuminori; Saito, Yasuo; Atarashi, Daiki*
Proceedings of 3rd International Symposium on Cement-based Materials for Nuclear Wastes (NUWCEM 2018) (USB Flash Drive), 4 Pages, 2018/10
At TRP, LWTF was constructed as a facility for processing low radioactive liquid waste and solid waste generated at TRP, and a cold test is been carrying out. In this facility, initially, nitrate waste liquid after separation of nuclides generated with treatment of low radioactive liquid waste was to be solidified by using borate. However, at present, it is necessary to decompose the nitrate in the liquid waste to reduce the environmental burden. For the reason, as a plan to replace the nitrate with the carbonate and to make it as a cement based encapsulation, we are studying for the introduction of the facility. Currently, as a cement solidification technology development for this liquid waste, we are studying the application of cement material based on blast furnace slag (BFS) as a main component. In this report, we show the results of the test conducted on the actual scale (200 L drum can scale).
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.
Goto, Yuichi; Yamamoto, Masahiko; Kuno, Takehiko; Inada, Satoshi
Nihon Hozen Gakkai Dai-15-Kai Gakujutsu Koenkai Yoshishu, p.489 - 492, 2018/07
Radioactive liquid waste from the Tokai Reprocessing Facility Analytical Laboratory is temporarily stored in intermediate waste storage tank by using receiving valves. Then, the liquid waste is transferred to liquid treatment facility by using liquid feed valves. The deterioration of the gasket part of these valves (leakage of waste liquid) was confirmed in 2004. Since then, the material of gaskets was changed from polyethylene to Teflon. In 2016, the gaskets were replaced by periodical update. Therefore, physical properties of used gaskets were investigated, and the relevance between radioactive level and degradation degree was evaluated.
Nakamura, Hironobu; Kitao, Takahiko; Yamada, Hiroyuki; Kono, Soma; Kimura, Takashi; Tasaki, Takashi
Proceedings of INMM 59th Annual Meeting (Internet), 9 Pages, 2018/07
Taguchi, Shigeo; Yamamoto, Masahiko; Furuse, Takahiro*; Masaki, Yuji*; Kuno, Takehiko
JAEA-Technology 2018-005, 14 Pages, 2018/06
The method to remove Pu, Am and Np from plutonium nitrate solution recovered from spent nuclear fuel prior to ICP-OES measurement has been developed for the determination of 18 impurity metal elements (Fe, Cr, Ni, Mn, Al, Cd, V, Cu, Si, Zn, Mo, Sn, Ca, Mg, Na, Ag, Pb, B). In this method, two TRU resin packed columns were used for separation. In the first column, Pu and Am were mainly removed by adsorption. The recovered solution from the fist column was added to the second column after reduction of Np, and Am(III) and Np(IV) were removed by adsorption. The Pu nitrate solution (22g/L) of 2mL were treated by proposed method. The alpha emission nuclide was decreased to 5.8 Bq/mL in a solution diluted to 100mL. As a result of ICP-OES measurement, the recoveries of impurity metals separated by proposed method were almost 100%. This separation scheme can apply to the metal impurity elemental analysis in Pu nitrate solution recovered from spent nuclear fuel.
Do, V. K.; Yamamoto, Masahiko; Taguchi, Shigeo; Takamura, Yuzuru*; Surugaya, Naoki; Kuno, Takehiko
Talanta, 183, p.283 - 289, 2018/06
We develop a novel analytical method employing liquid electrode plasma optical emission spectrometry for measurement of total cesium in highly active liquid wastes. Limit of detection and limit of quantification are 0.005 mg/L and 0.02 mg/L, respectively. The method is validated and applied to the real samples.