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JAEA Reports

Development of "MOX weighing and Ball-mill blending" based on experience in operation and maintenance of MOX fuel manufacturing equipment

Kawasaki, Kohei; Ono, Takanori; Shibanuma, Kimikazu; Goto, Kenta; Aita, Takahiro; Okamoto, Naritoshi; Shinada, Kenta; Ichige, Hidekazu; Takase, Tatsuya; Osaka, Yuki; et al.

JAEA-Technology 2022-031, 91 Pages, 2023/02

JAEA-Technology-2022-031.pdf:6.57MB

The document for back-end policy opened to the public in 2018 by Japan Atomic Energy Agency (hereafter, JAEA) states the decommissioning of facilities of Nuclear Fuel Cycle Engineering Laboratories and JAEA have started gathering up nuclear fuel material of the facilities into Plutonium Fuel Production Facilities (hereafter, PFPF) in order to put it long-term, stable and safe storage. Because we planned to manufacture scrap assemblies almost same with Monju fuel assembly using unsealed plutonium-uranium mixed-oxide (hereafter, MOX) powder held in PFPF and transfer them to storage facilities as part of this "concentration" task of nuclear fuel material, we obtained permission to change the use of nuclear fuel material in response to the new regulatory Requirements in Japan for that. The amount of plutonium (which is neither sintered pellets nor in a lidded powder-transport container) that could be handled in the pellet-manufacturing process was limited to 50 kg Pu or less in order to decrease the facility risk in this manufacture. Therefore, we developed and installed the "MOX weighing and blending equipment" corresponding with small batch sizes that functioned in a starting process and the equipment would decrease handling amounts of plutonium on its downstream processes. The failure data based on our operation and maintenance experiences of MOX fuel production facilities was reflected in the design of the equipment to further improve reliability and maintainability in this development. The completed equipment started its operation using MOX powder in February 2022 and the design has been validated through this half-a-year operation. This report organizes the knowledge obtained through the development of the equipment, the evaluation of the design based on the half-a-year operation results and the issues in future equipment development.

JAEA Reports

A Study on modeling and numerical simulation of extraction in the CMPO-TBP system

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JNC TN8400 2001-022, 60 Pages, 2001/03

JNC-TN8400-2001-022.pdf:1.31MB

A numerical simulation code for the TRUEX (Transuranium Extraction) process was developed. Concentration profiles of americium and europium were calculated for some experiments of the counter current extraction system those were carried out in CPF (Chemical Processing Facility) by using the code. Calculation profiles were in agreement with the experimental results. Operational conditions were also examinted for the americium recovery experiment by the TRUEX process carried out in the Plutonium Fuel Center. It was shown that lowering the concentration of nitric acid in the scrub solution and decreasing the flow rate of solvent and strip solution was effective for improving the performance of the stripping step and reducing the volume of the waste solution. In order to find the optimum conditions for various experiments, this simulation code was modified to calculate the concentration profiles of other metal elements such as zirconium and iron and the effect of oxalic acid on the extraction behavior of the metal elements. The calculated concentration profiles of americium and europium were varied by this modification. In the experiment at CPF, the calculations were carried out to obtain recovery ratio of americium in the product stream with the amount of oxalic acid added to the process. This calculation result showed that it was possible to improve the performance of decontamination of fission products by increasing oxalic acid concentration added to the process. The calculation was also carried out for finding the optimum conditions of oxalic acid concentration added to the europium recovery process.

JAEA Reports

Evaluation of the analytical errors jn plutonium and uranium isotopic composition analysis based on routine control measurement data (1998/92000/12)

Kobayashi, Hideo; ; ; ; ; *; *

JNC TN8440 2001-005, 33 Pages, 2001/02

JNC-TN8440-2001-005.pdf:1.24MB

Four mass spectrometers are used for plutonium and uranium isotopic composition analysis in the Plutonium Fuel Center. Analytical errors of the analysis was evaluated based on routine control data obtained with measurement of reference materials. It was confirmed that the errors satisfied the International Target Values for safeguard analysis, and the random error of the analysis was improved by changing conventional method to total evaporation method.

JAEA Reports

Inspection procedure of MONJU fuel pellet

Kajiyama, Tadashi;

JNC TN8410 2000-015, 7 Pages, 2000/10

JNC-TN8410-2000-015.pdf:0.09MB

Some falsification has been detected in the results of quality control data relating to the diameter of samples of pellets produced in the BNFL's MOX Demonstration Facility (MDF) on September 1999. This document is the outlines of inspection procedure for the MONJU fuel pellet in plutonium fuel center of JNC.

JAEA Reports

Study on reducing the generation of general waste

Aoki, Isao; ; Haga, Tetsuya; ; Sudo, Katsuo; Tsunashima, Yasumichi;

JNC TN8420 2000-005, 42 Pages, 2000/04

JNC-TN8420-2000-005.pdf:2.09MB

On August 1999, the Director of Tokai Work proposed an activity regarding recycling and reuse of general waste generated from Tokai Works. The activity was initiated by the Waste Management and Fuel Cycle Research Center, and is now being in progress through out the Tokai Works. In the course of this activity, Plutonium Fuel Center had settled the Working Group and the issues related to the waste reduction have been examined. This report collects the problems that became obvious through the survey of existing segregation method, treatment process, and the amount of the waste generation, and accounts for the concrete methodology for the recycling and reuse of general waste. In order to reduce waste, it is necessary to aware of the facing issues and adopt the countermeasures proposed in this report whenever possible. The activity will then leads us to reduce waste generation, which in turn will enable us to make 100 % waste recycling possible.

JAEA Reports

Report of lower endplug welding, and testing and inspecting result for MONJU 1 $^{st}$ reload core fuel assembly

Kajiyama, Tadashi; Numata, Kazuaki; Otani, Seiji; *; *; Goto, Tatsuro*; Takahashi, Hideki*

JNC TN8440 2000-008, 34 Pages, 2000/02

JNC-TN8440-2000-008.pdf:2.13MB

The procedure and result of lower endplug welding, Test and Inspection and Shipment of the 1 $^{st}$ reload core fuel assembly (80 Fuel Assemblies) for the fast breeder reactor MONJU should be report, which had examined and inspected in Tamatsukuri Branch, Material Insurance office, Quality Assurance Section, Technical Administration Division, Plutonium Fuel Center (before: Inspection Section, Plutonium Fuel Division), from June 1994 to January 1996. The number of cladding tubes welded to the endplug were total to 13,804, 7,418 for Core - Inside of 43 fuel Assemblies and 6,386 for Core-Outside of 37 fuel Assemblies. 13,794 of them, 7,414 Core-Inside and 6,379 Core-Outside were approved by the test and sent to Plutonium Fuel Center. 10 of them weren't approved mainly because of default welding. Disapproval rating is 0.07%.

JAEA Reports