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JAEA Reports

Analysis work report on removal of spent fuel sheared powder for decommissioning of main plant

Aoya, Juri; Mori, Amami; Sato, Hinata; Kono, Soma; Morokado, Shiori; Horigome, Kazushi; Goto, Yuichi; Yamamoto, Masahiko; Taguchi, Shigeo

JAEA-Technology 2023-008, 34 Pages, 2023/06

JAEA-Technology-2023-008.pdf:1.92MB

Flush-out, by which nuclear materials in the Tokai Reprocessing Plant process are recovered, has been started in June 2022 as the first step of decommissioning. Flush-out consists of removal of spent fuel sheared powder, plutonium solution, uranium solution, and the other nuclear materials. Removal of spent fuel sheared powder has been completed in September 2022. During removal of spent fuel sheared powder, uranium concentration, plutonium concentration, acid concentration, radioactivity concentration, and solution density have been analyzed for process control. For nuclear material accountancy, uranium concentration, plutonium concentration, isotope ratio, and solution density have been analyzed. Analysis work including sample pretreatment before transportation to IAEA analytical facility for safeguards, and the other operations related to Flush-out such as calibration of analytical instruments, education, and training of operators are reported.

Journal Articles

Accurate and precise measurement of uranium content in uranium trioxide by gravimetry; Comparison with isotope dilution mass spectrometry and its uncertainty estimation

Yamamoto, Masahiko; Horigome, Kazushi; Kuno, Takehiko

Applied Radiation and Isotopes, 190, p.110460_1 - 110460_7, 2022/12

 Times Cited Count:1 Percentile:33.72(Chemistry, Inorganic & Nuclear)

Gravimetric measurement of U content in UO$$_{3}$$ with ignition in the air has been investigated. The ignition temperature, ignition time and aliquot sample mass are optimized as 900$$^{circ}$$C, 60 minutes, and 1 g, respectively. The method is validated by IDMS with uncertainty estimation. The obtained result by gravimetry is 0.78236$$pm$$0.00051 g/g (k=2) and agreed with IDMS value within its uncertainty. It has been found that U in UO$$_{3}$$ can be measured accurately and precisely by gravimetry.

JAEA Reports

Completion of waste removal work from the hot cell of Operation Testing Laboratory in Tokai Reprocessing Plant

Goto, Yuichi; Suzuki, Yoshimasa; Horigome, Kazushi; Miyamoto, Toshihiko*; Usui, Masato*; Mori, Eito*; Kuno, Takehiko

JAEA-Technology 2022-005, 42 Pages, 2022/07

JAEA-Technology-2022-005.pdf:4.48MB

Radioactive wastes were generated and stored in the hot cell of Operation Testing Laboratory of Tokai Reprocessing Plant due to the experiments related to the reprocessing technology development from 1974 to 2014. Waste removal work was strengthened by the shift work in the past, however another wastes were generated by the equipment dismantling. From 2006, an improved waste removal method was established by using bag-out technique and wastes were taken from the glove-box connected to the hot cell. The removal period, estimated from the conventional method using Cask No. 10, was reduced from 14 to 5 years. From 2016, upgrade of worker's awareness including related departments was performed by various software and hardware improvements. Also, the worker's skills were improved and equipment in Cask No.10 was checked for preventive maintenance. The prevention measures for past troubles were discussed with Radiation Control Department. In addition, transportation schedule including safety operation with Transportation Department and Waste Receiving Department was optimized to maintain the waste removal cycle. The removal period was reduced from 5 to 3 years by the above efforts. Finally, the work was completed in March 2020.

Journal Articles

Effect of surface conditions of the filament used in thermal ionization mass spectrometry on an uranium isotopic measurement

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 ($$^{235}$$U/$$^{238}$$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 ($$^{235}$$U/$$^{238}$$U) measurement was improved.

Journal Articles

Separation technique using column chromatography for safeguards verification analysis of uranium and plutonium in highly-active liquid waste by isotope dilution mass spectrometry

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$$^{textregistered}$$ 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.

Journal Articles

Replacement of the glove port equipped with glove box in Nuclear Fuel Reprocessing Facility

Horigome, Kazushi; Taguchi, Shigeo; Nishida, Naoki; Goto, Yuichi; Inada, Satoshi; Kuno, Takehiko

Nihon Hozen Gakkai Dai-14-Kai Gakujutsu Koenkai Yoshishu, p.381 - 384, 2017/08

no abstracts in English

JAEA Reports

Preparation of uranium and plutonium mixed spike optimized for MOX analysis by isotope dilution mass spectrometry

Horigome, Kazushi; Taguchi, Shigeo; Yamamoto, Masahiko; Kuno, Takehiko; Surugaya, Naoki

JAEA-Technology 2017-016, 20 Pages, 2017/07

JAEA-Technology-2017-016.pdf:1.68MB

Mixed spikes of uranium and plutonium have been prepared for the determination of uranium and plutonium in dissolved MOX solution by isotope dilution mass spectrometry. Enriched uranium metal NBL CRM116 and plutonium metal NBL CRM126 were accurately weighed and then dissolved in nitric acid, respectively. Their dissolved solutions were mixed in a mass ratio of 1 to 2. The preparation values of uranium and plutonium were 1.0530 $$pm$$ 0.0008 mg/g (k=2) of uranium with a $$^{235}$$U relative mass fraction of 93.114 wt% and 2.0046 $$pm$$ 0.0019 mg/g (k=2) of plutonium with a $$^{239}$$Pu relative mass fraction of 97.934 wt%, respectively. The concentrations of uranium and plutonium in spike were confirmed by reverse isotope dilution mass spectrometry using tracer of $$^{233}$$U and $$^{242}$$Pu. Finally, the prepared spike was validated by parallel analysis of simulated sample of dissolved MOX solution. This spike was applied to measure the uranium and plutonium amount content of dissolved MOX solutions using isotope dilution mass spectrometry.

JAEA Reports

Report on analytical activities in potentially hazardous materials mitigation measures at the Plutonium Conversion Development Facility; 2015.12 $$sim$$ 2016.10

Horigome, Kazushi; Taguchi, Shigeo; Ishibashi, Atsushi; Inada, Satoshi; Kuno, Takehiko; Surugaya, Naoki

JAEA-Technology 2017-008, 14 Pages, 2017/05

JAEA-Technology-2017-008.pdf:1.15MB

The plutonium solution had been converted into MOX powder to mitigate the potential hazards of storage plutonium solution such as hydrogen generation at the Plutonium Conversion Development Facility. The plutonium conversion operations had been started in April, 2014, and had been finished in July, 2016. With respect to the samples taken from the conversion process, about 2,200 items of plutonium/uranium solutions and MOX powders had been analyzed for the operation control in the related analytical laboratories at the Tokai Reprocessing Plant. This paper describes the reports on analytical activities and related maintenance works in the analytical laboratories conducted from December, 2015 to October, 2016.

JAEA Reports

Report on analytical activities in potentially hazardous materials mitigation measures at the Plutonium Conversion Development Facility; 2014.4 $$sim$$ 2015.12

Horigome, Kazushi; Suzuki, Hisanori; Suzuki, Yoshimasa; Ishibashi, Atsushi; Taguchi, Shigeo; Inada, Satoshi; Kuno, Takehiko; Surugaya, Naoki

JAEA-Technology 2016-026, 21 Pages, 2016/12

JAEA-Technology-2016-026.pdf:1.14MB

In order to mitigate potential hazards of storage plutonium in solution such as hydrogen generation, conversion of plutonium solution into MOX powder has been carried out since 2014 in the Plutonium Conversion Development Facility. With respect to the samples taken from the conversion process, about 3500 items of plutonium/uranium solutions and MOX powders have been analyzed for the operation control in the related analytical laboratories at the Tokai Reprocessing Plant. This paper describes the reports on analytical activities and related maintenance works in the analytical laboratories conducted from April 2014 to December 2015.

Journal Articles

Feasibility study of technology for Pu solution monitoring including FP; Composition research of high active liquid waste and radiation measurement results on the surface of cell

Matsuki, Takuya; Masui, Kenji; Sekine, Megumi; Tanigawa, Masafumi; Yasuda, Takeshi; Tsutagi, Koichi; Ishiyama, Koichi; Nishida, Naoki; Horigome, Kazushi; Mukai, Yasunobu; et al.

Proceedings of INMM 57th Annual Meeting (Internet), 9 Pages, 2016/07

The International Atomic Energy Agency (IAEA) has proposed in its long-term research and development (R&D) plan, development of a real-time measurement technology to monitor and verify nuclear material movement continuously as part of an advanced approach to effectively and efficiently conduct safeguards for reprocessing facilities. Since the Tokai Reprocessing Plant (TRP) has solutions containing both Pu and fission products (FP), a new detector development project to monitor Pu with FP is being carried out from 2015 to 2017. This project is mainly conducted in the High Active Liquid Waste Storage (HALWS) in the TRP. For the first step of this project, as the confirmation of composition of high active liquid waste (HALW) to evaluate neutron/$$gamma$$-ray emitted from solution in the selected HALW tank which has the most amount of Pu in HALW tanks at the TRP, we took HALW sample and conducted $$gamma$$-ray spectrum measurement for HALW. As a study of detector setting location, to survey the available neutron/$$gamma$$-ray (i.e. intensity) at the outside surface of the cell where HALW tank is located, we implemented continuous measurement by neutron/$$gamma$$-ray detector. In this paper, we report three $$gamma$$-ray peaks related with $$^{238}$$Pu and $$^{239}$$Pu measured in the composition research of HALW, which is needed to identify Pu amount by the new detector that we are developing and the result of radiation measurement on the surface of the cell.

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.

Oral presentation

Measurement technology for safeguards analysis at the Tokai reprocessing plant

Yamamoto, Masahiko; Surugaya, Naoki; Taguchi, Shigeo; Ishibashi, Atsushi; Horigome, Kazushi; Yamazaki, Hitoshi; Ogura, Hiroshi; Watahiki, Hiromi; Watanabe, Masahisa; Kurosawa, Akira; et al.

no journal, , 

no abstracts in English

Oral presentation

Development of flow analysis system for determination of trace amounts of uranium and metallic elements in nitric acid solutions

Horigome, Kazushi; Taguchi, Shigeo; Yamamoto, Masahiko; Surugaya, Naoki; Kurosawa, Akira

no journal, , 

no abstracts in English

Oral presentation

Preparation of the spike for isotope dilution mass spectrometry-optimization of mixing ratio of U and Pu for the measurement of U-Pu MOX powder

Horigome, Kazushi; Suzuki, Yoshimasa; Yamamoto, Masahiko; Taguchi, Shigeo; Kuno, Takehiko; Surugaya, Naoki

no journal, , 

no abstracts in English

Oral presentation

Training of chemical analysis technique of radioactive materials in actual field

Masaki, Yuji*; Miyauchi, Hironari*; Taguchi, Shigeo; Horigome, Kazushi; Ishibashi, Atsushi; Yamamoto, Masahiko; Masui, Kenji; Nishida, Naoki; Kuno, Takehiko; Surugaya, Naoki

no journal, , 

Reprocess the technology development center has longtime experience for the handling of the radiation and perform support aiming at the acquisition of the spot analysis technique about the radioactive nuclear material handling in response to a demand out of the mechanism.

Oral presentation

Feasibility study of technology for Pu solution monitoring including FP, 4; Comparison between dose rate measurement result and simulation result

Matsuki, Takuya; Nishida, Naoki; Horigome, Kazushi; Sekine, Megumi; Kitao, Takahiko; Nakamura, Hironobu

no journal, , 

To inquest the measurement point of the detector which can conduct the Pu monitoring in the high active liquid waste at Tokai reprocessing plant, we have made the simulation model which can calculate the radiation distribution in the cell storing HALW. Comparing the dose rate distribution between calculation result and actual measurement result, we evaluated the validity of the current simulation model.

Oral presentation

Preparation of mixed spike with $$^{239}$$Pu and $$^{235}$$U for MOX analysis by isotope dilution mass spectrometry and application to actual sample

Horigome, Kazushi; Taguchi, Shigeo; Yamamoto, Masahiko; Inada, Satoshi; Kuno, Takehiko

no journal, , 

no abstracts in English

Oral presentation

Development of analytical methods for iodine-129 in sample from reprocessing plant by inductively coupled plasma mass spectrometry with collision reaction cell technique

Saegusa, Yu; Kodaka, Noriyasu; Yamamoto, Masahiko; Horigome, Kazushi; Inada, Satoshi; Kuno, Takehiko

no journal, , 

Iodine-129 ($$^{129}$$I), which is a long-lived radionuclide, has high analytical needs for trace concentrations in gaseous and liquid radioactive waste to evaluate the environmental impact of treatment and disposal. However, conventional analytical methods such as gamma ray spectrometry, liquid scintillation counter, and inductively coupled plasma mass spectrometry (ICP-MS) are difficult to apply due to measurement sensitivity and isobaric interference. In this study, we have been developed analytical method for $$^{129}$$I by ICP-MS with collision reaction cell technique. Reaction gas has been introduced into the collision reaction cell and isobaric ion has been eliminated. In this presentation, the measurement results of $$^{129}$$I in the iodine adsorption filter collected from the liquid waste treatment facility of Tokai Reprocessing Plant is reported.

Oral presentation

Development of analytical method for selenium-79 and iodine-129 in sample from reprocessing process by inductively coupled plasma mass spectrometry with collision reaction cell technique, 2

Saegusa, Yu; Kodaka, Noriyasu; Yamamoto, Masahiko; Horigome, Kazushi; Inada, Satoshi; Kuno, Takehiko

no journal, , 

Determination of iodine-129, in sample of reprocessing process has high priority to evaluate the environmental impact at treatment and disposal of radioactive solid wastes. In this study, we have been developed analytical method for iodine-129 by ICP-MS with collision reaction cell technique. Oxygen gas has been introduced into the collision reaction cell and isobaric ion, xenon-129, has been eliminated. In this presentation, optimized oxygen gas flow rate, analytical performance, and the measurement results of iodine-129 in the iodine adsorption filter collected from the liquid waste treatment facility in Tokai Reprocessing Plant are reported.

Oral presentation

Applicability evaluation of uranium and plutonium analysis by a handheld X-ray fluorescence analyzer

Kono, Soma; Horigome, Kazushi; Yamamoto, Masahiko; Taguchi, Shigeo

no journal, , 

no abstracts in English

25 (Records 1-20 displayed on this page)