Improvement construction for ground around High Active liquid Waste facility in Tokai Reprocessing Plant

Omori, Kazuki; Yamauchi, Sho; Yanagibashi, Futoshi; Sasaki, Shunichi; Wada, Takuya; Suzuki, Hisanori; Domura, Kazuyuki; Takeuchi, Kenji

Nihon Hozen Gakkai Dai-18-Kai Gakujutsu Koenkai Yoshishu, p.245 - 248, 2022/07

Tokai Reprocessing Plant (TRP), which is shifted to decommissioning stage, stores large amount of high-level radioactive liquid waste (HLLW). Although TRP is implementing vitrification of HLLW to reduce the risks related to HLLW storage, additional 20 years are required to complete vitrification of HLLW. Therefore, TRP is implementing safety countermeasure related to seismic resistance of HLLW storage facility as one of the top priorities. The results of the seismic evaluation indicate that although the facility itself is seismically resistant, there is a risk of insufficient binding force acting between the facility and the surrounding ground. Thus, replacement of the surrounding ground with concrete is performed. Since the countermeasures, to protect existing buries structure and coordinate with the other construction projects around the site, are required, the dedicated team was setup to handle the process and safety management of the concrete replacement construction.

Manufacturability estimation on burnable poison mixed fuel for improving criticality safety of HTGR fuel fabrication

Hasegawa, Toshinari; Fukaya, Yuji; Ueta, Shohei; Goto, Minoru

Proceedings of 28th International Conference on Nuclear Engineering (ICONE 28) (Internet), 5 Pages, 2021/08

https://doi.org/10.1115/ICONE28-61763

Burnable poison (BP) credit concept has been proposed as a criticality safety measure for commercial high temperature gas-cooled reactor (HTGR) fuel fabrication, so we estimated manufacturability of the BP-mixed UO kernel for the practical use of the concept. As a BP, boron, gadolinium, erbium, and hafnium are investigated. Boron mixed fuel kernels are fabricated by mixing boric acid powder with UO powder. In the case of the other BPs, BP nitrate powder is mixed with UO powder. In order to confirm that BP remain in the kernels after the heat treatment processes, thermodynamic equilibrium analysis was performed. Above 450C, boron would melt and vaporize during the heat treatment processes, so it was found that the boron mixed fuel kernel fabrication is difficult. On the other hand, it was found that gadolinium, erbium, and hafnium would change to solid oxides that do not melt and vaporize even at 2000C, and there was no problem with manufacturability of the BP-mixed fuel kernel.

Safety measures in the melting facilities of The Advanced Volume Reduction Facilities; Document collection of discussion meetings related to melting facilities

Iketani, Shotaro; Yokobori, Tomohiko; Ishikawa, Joji; Yasuhara, Toshiyuki*; Kozawa, Toshiyuki*; Takaizumi, Hirohide*; Momma, Takeshi*; Kurosawa, Shingo*; Iseda, Hirokatsu; Kishimoto, Katsumi; et al.

JAEA-Review 2018-016, 46 Pages, 2018/12

JAEA-Review-2018-016.pdf:12.79MB

Japan Atomic Energy Agency (JAEA) adopts melting process for the waste processing and packaging method of radioactive miscellaneous solid waste in NSRI because melting process is effective in radioactivity evaluation, volume reduction, and stabilization treatment. Metal melting processing facilities, Incinerator, and Nonmetal melting processing facilities (hereinafter referred to as melting process facilities) have taken lots of safety measures, including measures for preventing the recurrence of the fire accidents. To exchange opinions and discuss the validity of these measures and so on with internal personnel and external experts, "Discussions on Melting Process Facilities" was held. As a document collection, this paper summarizes presentation materials of discussion meetings. Presentation materials describe "Outline of AVRF", "Safety measures in the melting facilities in WVRF", "Operation management of the melting facilities in WVRF", "Comparison of the past accident cases between facilities in and outside Japan and WVRF", and "Introduction of past accident cases and safety measures in other facilities from each committee".

Pressure rise analysis when hydrogen leak from a cracked pipe in the cryogenic hydrogen system in J-PARC

Tatsumoto, Hideki; Aso, Tomokazu; Hasegawa, Shoichi; Ushijima, Isamu*; Kato, Takashi; Otsu, Kiichi*; Ikeda, Yujiro

AIP Conference Proceedings 823, p.753 - 760, 2006/05

https://doi.org/10.1063/1.2202483

As one of the main experimental facilities in J-PARC, an intense spallation neutron source (JSNS) driven by proton beam power of 1 MW is constructed. In JSNS, cryogenic hydrogen at supercritical pressure is selected as a moderator. The total nuclear heating at the moderators is estimated to be 3.7 kW. A cryogenic hydrogen system to cool the moderators has been designed. As the most severe off-normal event for cryogenic hydrogen system, it is considered that the cryogenic hydrogen leaks when the pipe is cracked. In such a case, the hydrogen must be discharged safely as soon as possible. An analytical code that simulated the pressure change during hydrogen leak was developed. The pressure rise analysis for various sized cracks was performed, and then the required size of safety equipment was determined. It was found from the analysis that a safety valve of -42.7 mm and a rupture disk with the diameter of 37.1 mm can discharge hydrogen safely.

Safety admimstration division business report; The second quarter of 2001

Kanamori, Masashi

JNC TN8440 2001-023, 110 Pages, 2001/12

JNC-TN8440-2001-023.pdf:3.91MB

The business of the Safety administration Division became a wide range such as the management of a labor safety health, the crisis management, the security and the management of an entrance, and the business of the following concerning the Tokai Works, the protection of nuclear materials, the business of the sanction, the nuclear material safeguards, the transport of nuclear materials and the business of a quality assurance. For the purpose of summarizing these businesses and utilizing the data concerning the businesses, the report about the businesses achievement has been periodically drawn up as quarter news since 2001, when the Safety Administration Division was established. This report describes about the business achievement of the second quarter news from July to September in 2001.

Safety considerations for continuous hydrogen production test apparatus wtih capacity of 50 N-litter hydrogen per hour

Onuki, Kaoru; Akino, Norio; Shimizu, Saburo; Nakajima, Hayato; Higashi, Shunichi; Kubo, Shinji

JAERI-Tech 2001-032, 63 Pages, 2001/03

JAERI-Tech-2001-032.pdf:4.63MB

no abstracts in English

Conceptual design of the handling and storage system of the spent target vessel for a MW-class neutron scattering facility

Adachi, Junichi*; Kaminaga, Masanori; Sasaki, Shinobu; Hino, Ryutaro

JAERI-Tech 2000-068, 86 Pages, 2000/11

JAERI-Tech-2000-068.pdf:4.39MB

no abstracts in English

Report of radiation exposure control on the 12th periodic inspection at experimental fast reactor JOYO

; Kano, Yutaka; ; Shindo, Katsutoshi

JNC TN9410 2000-001, 20 Pages, 1999/12

JNC-TN9410-2000-001.pdf:1.84MB

The 12th periodic inspection had been executed at the experimental fast reactor JOYO from February 24,1998 to June 28,1999. This inspection had been extended about three months because it was addtion to the work for the safety countermeasure. The result of collective dose equivalent was 263.92 man*mSv, whereas, the expected collective dose equivalent was about 407 man*mSv in the whole period of this inspection. It was confirmed that this inspection was carried out with the suitable radiation protection programmes. In this report, provided in 12th periodic inspection, were described with taking the results of the past periodic inspections into consideration.

None

JNC TN1400 99-017, 439 Pages, 1999/08

JNC-TN1400-99-017.pdf:14.06MB

no abstracts in English

None

; ;

PNC TN8440 94-013, 72 Pages, 1994/03

PNC-TN8440-94-013.pdf:2.94MB

None