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.

Numerical evaluation of the light transport properties of alternative He-3 neutron detectors using ceramic scintillators

Ozu, Akira; Takase, Misao*; Haruyama, Mitsuo; Kurata, Noritaka*; Kobayashi, Nozomi*; Kureta, Masatoshi; Nakamura, Tatsuya; To, Kentaro; Sakasai, Kaoru; Suzuki, Hiroyuki; et al.

Nuclear Instruments and Methods in Physics Research A, 798, p.62 - 69, 2015/10

https://doi.org/10.1016/j.nima.2015.07.020

The light transport properties of scintillator light inside alternative He-3 neutron detector modules using scintillator sheets have been investigated by a ray-tracing simulation code. The detector module consists of a light-reflecting tube, a thin rectangular ceramic scintillator sheet laminated on a glass plate, and two photo-multiplier tubes (PMTs) mounted at both ends of the detector tube. The light induced on the surface of the scintillator sheet via nuclear interaction between the scintillator and neutrons are detected by the two PMTs. The light output of various detector modules in which the scintillator sheets are installed with several different arrangements were examined and evaluated in comparison with experimental results. The results derived from the simulation reveal that the light transport property is strongly dependent on the arrangement of the scintillator sheet inside the tube and the shape of the tube.

Evaluation of light transport property in alternative He-3 neutron detectors using ceramic scintillators by a ray-tracing simulation

Ozu, Akira; Takase, Misao*; Kurata, Noritaka*; Kobayashi, Nozomi*; Tobita, Hiroshi; Haruyama, Mitsuo; Kureta, Masatoshi; Nakamura, Tatsuya; Suzuki, Hiroyuki; To, Kentaro; et al.

Proceedings of 2014 IEEE Nuclear Science Symposium and Medical Imaging Conference; 21st International Symposium on Room-Temperature Semiconductor X-ray and -ray detectors (NSS/MIC 2014), 5 Pages, 2014/00

https://doi.org/10.1109/NSSMIC.2014.7431175

In Japan Atomic Energy Agency, the helium-3 alternative neutron detector using ceramic scintillators for nuclear safeguards is under development with the support of the government. The alternative detector module consists of four components: an aluminum regular square tube, a light reflecting foil put on the inner surface of the square tube, a rectangular scintillator sheet sintered on a glass plate, and two PMTs provided at both ends of the tube. The scintillator sheet is fit on the diagonal inside the square tube. The light transport property of scintillator lights inside the tube influences on the fundamental performance of the alternative detector. Therefore, the properties of the lights emitted on the surface of the scintillator sheet and scintillation lights passing through the glass plate to the PMTs in several arrangements of the scintillator in the tubes were investigated with a ray-tracing simulation. The results are described in comparison with the experimental results.

Development of a ZnS/BO ceramic scintillator neutron detector for safeguards NDA systems

Nakamura, Tatsuya; To, Kentaro; Sakasai, Kaoru; Suzuki, Hiroyuki; Soyama, Kazuhiko; Kureta, Masatoshi; Ozu, Akira; Takase, Misao; Nakamura, Hironobu; Seya, Michio

Proceedings of INMM 54th Annual Meeting (CD-ROM), 8 Pages, 2013/07

We have developed a neutron detector by using ZnS/BO ceramic scintillator for nuclear safeguards NDA systems. The detector has a simple structure where ZnS/BO ceramic scintillator is implemented in the light reflecting case and two PMTs are connected at either end of it. The ZnS/BO ceramic scintillator was originally developed for a two-dimensional neutron detector in the Japan Proton Accelerator Research Complex in Materials and Life Science Experimental Facility. No organic binder material is used in the scintillator, which makes it suitable to a detector operating under -ray irradiation over a long period of time. A neutron absorption probability can be increased by installing two scintillator strips in cross arrangement. In the presentation present status of detector development including detector design, detection system and experimental results measured with a prototype detector will be presented.

Optical guide property of alternative He-3 neutron detectors using solid scintillators for nuclear safeguards

Ozu, Akira; Nakamura, Tatsuya; Takase, Misao; Kurata, Noritaka; Haruyama, Mitsuo; Kureta, Masatoshi; Soyama, Kazuhiko; Seya, Michio

Proceedings of 2013 IEEE Nuclear Science Symposium and Medical Imaging Conference Record (NSS/MIC), 4 Pages, 2013/00

https://doi.org/10.1109/NSSMIC.2013.6829640

Alternative He-3 neutron detectors using inorganic solid (ZnS:Ag/10BO) scintillators for nuclear safeguards have been developed in Japan Atomic Energy Agency (JAEA). The detector module is made mainly of three components: an aluminum regular square tube (32 mm 32 mm 300 mm), a rectangular scintillator sheet (39 mm 250 mm) and two PMTs. The scintillator sheet is fit on the diagonal inside the square tube, while the two PMTs are installed at both ends of the tube. At present, the detection efficiency of around 50% of that of the He-3 gas detector has been already achieved. The ray sensitivity of 510 is also obtained. The fundamental performance of the alternative detector is strongly dependent on the optical guide property of scintillation lights inside of the tube. The transport properties of the scintillation lights detected with the PMTs was evaluated by a ray-tracing simulation. The results are discussed in comparison with the experimental results.

Development plan of Pu NDA system using ZnS ceramic scintillator

Kureta, Masatoshi; Soyama, Kazuhiko; Seya, Michio; Ozu, Akira; Haruyama, Mitsuo; Takase, Misao; Sakasai, Kaoru; Nakamura, Tatsuya; To, Kentaro

Proceedings of INMM 53rd Annual Meeting (CD-ROM), 8 Pages, 2012/07

Alternative techniques to neutron detection by helium-3 for nuclear security and safeguards systems are necessary to be developed since helium-3 shortage is serious. With support of Japanese government (the Ministry of Education, Culture, Sports, Science and Technology), we have started an R&D project of Pu NDA system using ZnS ceramic scintillator. Here we present development plan, production of a new type of ZnS ceramic scintillator experimentally and basic design of a PCAS alternative Pu NDA system. We are planning the demonstration tests using the alternative NDA system comparing with the current PCAS in which the helium-3 counters are installed.

Analytical study on optical guide property of solid scintillation neutron detectors

Ozu, Akira; Kureta, Masatoshi; Seya, Michio; Haruyama, Mitsuo; Takase, Misao; Kurata, Noritaka; Soyama, Kazuhiko; Nakamura, Tatsuya

no journal, , 

no abstracts in English

Alternative He-3 neutron detectors using solid scintillator for nuclear safeguard, 3; Multi-channel ADC / DSP board for scintillator modular detector

Ebine, Masumi; Birumachi, Atsushi; Nakamura, Tatsuya; Ozu, Akira; Takase, Misao; To, Kentaro; Sakasai, Kaoru; Soyama, Kazuhiko; Kureta, Masatoshi; Seya, Michio

no journal, , 

no abstracts in English

Alternative He-3 neutron detectors using solid scintillator for nuclear safeguard, 1

Nakamura, Tatsuya; Ozu, Akira; To, Kentaro; Ebine, Masumi; Birumachi, Atsushi; Suzuki, Hiroyuki; Honda, Katsunori; Takase, Misao; Kurata, Noritaka; Haruyama, Mitsuo; et al.

no journal, , 

no abstracts in English

Design and manufacture of alternative plutonium canister assay system using alternative He-3 neutron detectors

Ozu, Akira; Takase, Misao; Kurata, Noritaka; Kobayashi, Nozomi; Yoshino, Seiji; Kureta, Masatoshi; Nakamura, Tatsuya; Soyama, Kazuhiko; Nakamura, Hironobu; Seya, Michio; et al.

no journal, , 

no abstracts in English