Development of plutonium fuel facility decommissioning technology to accelerate glovebox dismantling and reduce air-fed suits based operations

Yoshida, Masato; Iguchi, Satoshi; Hirano, Hiroshi*; Kitamura, Akihiro

Nuclear Engineering and Design, 431, p.113691_1 - 113691_16, 2025/01

https://doi.org/10.1016/j.nucengdes.2024.113691

The Plutonium Fuel Fabrication Facility is currently in the decommissioning phase, with glovebox dismantling operations ongoing since 2010. During conventional glovebox dismantling operations, the glovebox to be dismantled is enclosed within plastic tents to contain contamination. The glovebox is then dismantled by workers wearing air-fed suits with thermal or mechanical cutting tools, which typically generate dross or sparks in the form of radioactive aerosols during cutting. Despite the longevity and meticulous organization of this manual method, the workload remains considerable, while the allowable working time is limited. In addition, the potential for inhalation exposure to plutonium is elevated in the event of an accident given the contamination of the work area. To overcome disadvantages associated with conventional glovebox dismantling methods, new methods are currently being developed. The primary objective is to reduce the reliance on operation based on air-fed suits and enhance worker safety by introducing remote equipment and a new floor-reinforcing panel. Another objective is to suppress waste generation by reusing all equipment on multiple occasions which is achieved by developing a containment system that have a large open port with a pallet for the storage and reuse of equipment for successive operations. Furthermore, a glove operation compartment is designed and tested for the manual handling of dismantled materials as an additional strategy to reduce work based on air-fed suits and mitigate secondary waste generation.

Cleaning of the inner surface for Separated-type Drift Tube Linac with Dilute Hydrochloric Acid

Arai, Sora; Kosaka, Satoshi*; Nemoto, Yasuo*; Kitamura, Ryo

JAEA-Technology 2023-009, 18 Pages, 2023/05

JAEA-Technology-2023-009.pdf:1.89MB

The linac located at the head of the J-PARC accelerators and required to provide the stable and high-quality beam. One of the accelerating cavities in the linac is the Separated-type Drift Tube Linac (SDTL). It is important to appropriately apply the RF power into the cavity for the stable operation. However, after the recovery from the Great East Japan Earthquake, the RF power could not be applied into the cavities for several SDTL cavities because the voltage standing wave ratio increased around the designed operating power. The investigation revealed that the inner surface of the cavity was exposed to high humidity and the backflow of oil from the rotary pump for a long period of time after the earthquake. It was suggested that the residue on the inner surface caused the multipactor resulted in the failure when the power was applied. The residue was wiped out with organic solvents and acids, resulted in solving the failure. This report describes the method and results of the cleaning for the cavity in 2021.

Measurement of the longitudinal bunch-shape distribution for a high-intensity negative hydrogen ion beam in the low-energy region

Kitamura, Ryo; Futatsukawa, Kenta*; Hayashi, Naoki; Hirano, Koichiro; Kondo, Yasuhiro; Kosaka, Satoshi*; Miyao, Tomoaki*; Morishita, Takatoshi; Nemoto, Yasuo*; Oguri, Hidetomo

Physical Review Accelerators and Beams (Internet), 26(3), p.032802_1 - 032802_12, 2023/03

https://doi.org/10.1103/PhysRevAccelBeams.26.032802

A bunch-shape monitor (BSM) is a useful device for performing longitudinal beam tuning using the pointwise longitudinal phase distribution measured at selected points in the beam transportation. To measure the longitudinal phase distribution of a low-energy negative hydrogen (H) ion beam, highly oriented pyrolytic graphite (HOPG) was adopted for the secondary-electron-emission target to mitigate the thermal damage due to the high-intensity beam loading. The HOPG target enabled the measurement of the longitudinal phase distribution at the center of a 3-MeV H ion beam with a high peak current of about 50 mA. The longitudinal bunch width was measured using HOPG-BSM at the test stand, which was consistent with the beam simulation. The correlation measurement between the beam transverse and longitudinal planes was demonstrated using HOPG-BSM. The longitudinal Twiss and emittance measurement with the longitudinal Q-scan method was conducted using HOPG-BSM.

The Muon linac project at J-PARC

Kondo, Yasuhiro; Kitamura, Ryo; Fuwa, Yasuhiro; Morishita, Takatoshi; Moriya, Katsuhiro; Takayanagi, Tomohiro; Otani, Masashi*; Cicek, E.*; Ego, Hiroyasu*; Fukao, Yoshinori*; et al.

Proceedings of 31st International Linear Accelerator Conference (LINAC 2022) (Internet), p.636 - 641, 2022/09

https://doi.org/10.18429/JACoW-LINAC2022-WE1AA05

The muon linac project for the precise measurement of the muon anomalous magnetic and electric dipole moments, which is currently one of the hottest issues of the elementary particle physics, is in progress at J-PARC. The muons from the J-PARC muon facility are once cooled to room temperature, then accelerated up to 212 MeV with a normalized emittance of 1.5 mm mrad and a momentum spread of 0.1%. Four types of accelerating structures are adopted to obtain the efficient acceleration with a wide beta range from 0.01 to 0.94. The project is moving into the construction phase. We already demonstrated the re-acceleration scheme of the decelerated muons using a 324-MHz RFQ in 2017. The high-power test of the 324-MHz Interdigital H-mode (IH) DTL using a prototype cavity was performed in 2021. The fabrication of the first module of 14 modules of the 1296-MHz Disk and Washer (DAW) CCL will be done to confirm the production process. Moreover, the final design of the travelling wave accelerating structure for the high beta region is also proceeding. In this paper, the recent progress toward the realization of the world first muon linac will be presented.

Bunch-size measurement of the high-intensity H beam with 3 MeV by the bunch-shape monitor

Kitamura, Ryo; Futatsukawa, Kenta*; Hayashi, Naoki; Hirano, Koichiro; Kondo, Yasuhiro; Kosaka, Satoshi*; Miyao, Tomoaki*; Nemoto, Yasuo*; Morishita, Takatoshi; Oguri, Hidetomo

JPS Conference Proceedings (Internet), 33, p.011012_1 - 011012_6, 2021/03

https://doi.org/10.7566/JPSCP.33.011012

The new bunch shape monitor (BSM) is required to measure the bunch size of the high-intensity H beam with 3 MeV at the front-end section in the J-PARC linac. The carbon-nano tube wire and the graphene stick are good candidates for the target wire of the BSM, because these materials have the enough strength to detect the high-intensity beam. However, since the negative high voltage of more than a few kV should be applied to the wire in the BSM, the suppression of the discharge is the challenge to realize the new BSM. After the high-voltage test to investigate the effect of the discharge from the wire, the detection of the signal from the BSM was successful at the beam core with the peak current of 55 mA using the graphene stick. The preliminary result of the bunch-size measurement is reported in this presentation.

Consideration of relationship between decommissioning with digital-twin and knowledge management

Taruta, Yasuyoshi; Yanagihara, Satoshi*; Hashimoto, Takashi*; Kobayashi, Shigeto*; Iguchi, Yukihiro; Kitamura, Koichi; Koda, Yuya; Tomoda, Koichi

Proceedings of 2020 International Conference on Nuclear Engineering (ICONE 2020) (Internet), 8 Pages, 2020/08

https://doi.org/10.1115/ICONE2020-16457

Decommissioning is a long-term project during which generations are expected to change. Therefore, it is necessary to appropriately transfer knowledge and technology to the next generation. In recent years, in the world of decommissioning, attempts have been made to apply advanced technologies such as utilization of knowledge management and virtual reality. This study describes adaptation in decommissioning from the viewpoint of utilizing IT technology called digital twin from the viewpoint of knowledge management.

Development of the bunch shape monitor using the carbon-nano tube wire

Kitamura, Ryo; Hayashi, Naoki; Hirano, Koichiro; Kondo, Yasuhiro; Moriya, Katsuhiro; Oguri, Hidetomo; Futatsukawa, Kenta*; Miyao, Tomoaki*; Otani, Masashi*; Kosaka, Satoshi*; et al.

Proceedings of 10th International Particle Accelerator Conference (IPAC '19) (Internet), p.2543 - 2546, 2019/06

https://doi.org/10.18429/JACoW-IPAC2019-WEPGW033

A bunch shape monitor (BSM) is one of the important instruments to measure the longitudinal phase space distribution. For example in the J-PARC linac, three BSMs using the tungsten wire are installed at the ACS section to measure the bunch shapes between the accelerating cavities. However, this conventional BSM is hard to measure the bunch shape of H beam with 3 MeV at the beam transport between the RFQ and DTL sections, because the wire is broken around the center region of the beam. The new BSM using the carbon-nano-tube (CNT) wire is being developed to be able to measure the bunch shape of the H beam with 3 MeV. The careful attention should be paid to apply the high voltage of 10 kV to the CNT wire. The several measures are taken to suppress the discharge from the wire and operate the CNT-BSM. This presentation reports the current status of the development and future prospective for the CNT-BSM.

Research concept of decommissioning knowledge management for the Fugen NPP

Taruta, Yasuyoshi; Yanagihara, Satoshi*; Iguchi, Yukihiro; Kitamura, Koichi; Tezuka, Masashi; Koda, Yuya

Proceedings of 26th International Conference on Nuclear Engineering (ICONE-26) (Internet), 6 Pages, 2018/07

https://doi.org/10.1115/ICONE26-81228

The IAEA are developed the discussion for those situations and pointed out the importance of nuclear knowledge management. The nuclear knowledge management is developing a database as nuclear knowledge management. In recent years, the IAEA has also advanced knowledge taxonomies on nuclear accidents. These studies are attempts to appropriately arrange and utilize huge amounts of information. Even in nuclear facilities in Japan, it is pointed out that veteran staff aging and loss of knowledge and skill caused by retirement. Therefore, we created a prototype database system to utilize past knowledge and information for ATR Fugen. Now, there are few cases of past decommissioning that can be utilized. This study of pilot model concept revealed that it is not sufficient to just prepare a past data and information. This is what information other than the construction report requires the decommissioning and what kind of information should be gathered.

, a mutant with reduced anthocyanins in immature seeds from , harbors a mutation in the MATE transporter

Kitamura, Satoshi; Ono, Yutaka; Narumi, Issey*

Plant Molecular Biology, 90(1-2), p.7 - 18, 2016/01

https://doi.org/10.1007/s11103-015-0389-8

Here, we used the Arabidopsis banyuls (ban) mutant, which accumulates anthocyanins, instead of colorless proanthocyanidin precursors, in immature seeds. We mutagenized ban plants and screened for mutants showing differences in pigmentation of immature seeds. The pale banyuls1 (pab1) mutation caused reduced anthocyanin pigmentation in immature seeds compared with ban, but showed normal expression of anthocyanin biosynthetic genes. Map-based cloning showed that two independent pab1 alleles disrupted the MATE-type transporter gene FFT/DTX35. Complementation of pab1 with FFT confirmed that mutation in FFT causes the pab1 phenotype. During development, FFT promoter activity was detected in the seed-coat layers that accumulate flavonoids. Anthocyanins accumulate in the vacuole and FFT fused to GFP mainly localized in the vacuolar membrane.

Isolation of carbon ions-induced mutants in exhibiting different anthocyanin accumulation patterns

Kitamura, Satoshi; Ono, Yutaka; Narumi, Issey*

JAEA-Review 2014-050, JAEA Takasaki Annual Report 2013, P. 72, 2015/03

https://doi.org/10.11484/jaea-review-2014-050

Ion beams have been used for isolation of novel mutants in a number of plant species in our laboratory. Re-mutagenesis by secondary irradiation of ion beams to already-established ion beam-induced mutants would be effective to modify plant characters step-by-step, because ion beams are likely to induce mutations at the limited regions of the genome. Here, we try to adapt the re-mutagenesis by secondary ion beam irradiation in model plant , for obtaining flavonoid mutants that have not been found so far by standard mutagenesis and screening methods.