High-temperature oxidation failure in reactivity-initiated accidents; An Evaluation of failure criteria based on oxygen concentration from the previous NSRR experiments

Luu, V. N.; Taniguchi, Yoshinori; Udagawa, Yutaka; Katsuyama, Jinya

Nuclear Engineering and Design, 442, p.114222_1 - 114222_15, 2025/10

https://doi.org/10.1016/j.nucengdes.2025.114222

Development of analysis methods for SFR severe accidents in JAEA and assessment of applicability to safety analysis

Tobita, Yoshiharu; Tagami, Hirotaka; Ishida, Shinya; Onoda, Yuichi; Sogabe, Joji; Okano, Yasushi

IAEA-TECDOC-2079, p.72 - 84, 2025/01

https://doi.org/10.61092/iaea.xpz1-gu7q

Since the fast reactor core is not in the maximum reactivity configuration, a hypothetical core disruptive accident could lead to the prompt criticality due to a change in the core material configuration, and the resulting energy generation has been one of the issues in fast reactor safety, and therefore appropriate measures are needed to mitigate and contain the effect of energy generated in the accident. In order to assess the effectiveness of these mitigative measures, a set of computer codes to analyze the event progressions and energy generation behavior in the ATWS of fast reactors have been developed, maintained, and improved under international collaboration in JAEA. Since the important physical phenomena, which govern the event progression, vary along with the progression of the accident, the whole accident process is divided into several phases in the analysis of accident, and dedicated analysis methods for each phase are provided to analyze the event progression in each phase. The organization and overview of these analysis methods are described in this paper. As a representative example of the validation approaches in applying these analysis methods to the reactor safety assessment in licensing procedure in Japan, the validation studies to confirm the applicability to reactor analysis of the SIMMER code for analyzing core material movement and reactor power, which is important to analyze the energy generation in the accident, are presented in the paper. The validation studies of the SIMMER code confirmed the applicability of SIMMER to the reactor analysis, while the critical phenomena that the effect of their uncertainty in the reactor analysis should be checked were also recognized.

High-temperature rupture failure of high-burnup LWR-MOX fuel under a reactivity-initiated accident condition

Taniguchi, Yoshinori; Mihara, Takeshi; Kakiuchi, Kazuo; Udagawa, Yutaka

Annals of Nuclear Energy, 195, p.110144_1 - 110144_11, 2024/01

https://doi.org/10.1016/j.anucene.2023.110144

Analytical study of SPERT-CDC test 859 using fuel performance codes FEMAXI-8 and RANNS

Taniguchi, Yoshinori; Udagawa, Yutaka; Amaya, Masaki

Annals of Nuclear Energy, 139, p.107188_1 - 107188_7, 2020/05

https://doi.org/10.1016/j.anucene.2019.107188

Measurement of neutron spectra produced in the forward direction from thick graphite, Al, Fe and Pb targets bombarded by 350 MeV protons

Iwamoto, Yosuke; Taniguchi, Shingo*; Nakao, Noriaki*; Itoga, Toshio*; Nakamura, Takashi*; Nakane, Yoshihiro; Nakashima, Hiroshi; Satoh, Daiki; Yashima, Hiroshi*; Yamakawa, Hiroshi*; et al.

Nuclear Instruments and Methods in Physics Research A, 562(2), p.789 - 792, 2006/06

https://doi.org/10.1016/j.nima.2006.02.056

Neutron energy spectra produced from thick targets play an important role in validation of calculation codes that are employed in the design of spallation neutron sources and the shielding design of accelerator facilities. However, appropriate experimental data were scarce in the forward direction for the incident energy higher than 100 MeV. In this study, neutron spectra at 0 degree from thick targets bombarded with 350 MeV protons were measured by the time-of-flight technique using an NE213. The targets used were graphite, Al, Fe and Pb and their thicknesses were chosen to be a little thicker than the stopping lengths. The experiment was carried out at the TOF course of the RCNP (Research Center of Nuclear Physics) ring cyclotron, Osaka University. The flight path length between center of the target and of an NE213 were 11.4 m for the measurement of low energy neutrons and 95 m for high energy neutrons. The experimental data are compared with the calculated results by using the Monte Carlo transport codes, such as MCNPX and PHITS codes.

User's manual of a supporting system for treatment planning in boron neutron capture therapy; JAERI computational dosimetry system

Kumada, Hiroaki; Torii, Yoshiya

JAERI-Data/Code 2002-018, 158 Pages, 2002/09

JAERI-Data-Code-2002-018.pdf:30.28MB

A boron neutron capture therapy (BNCT) with epithermal neutron beam is expected to treat effectively for malignant tumor that is located deeply in the brain. It is indispensable to estimate preliminarily the irradiation dose in the brain of a patient in order to perform the epithermal neutron beam BNCT. Thus, the JAERI Computational Dosimetry System (JCDS), which can calculate the dose distributions in the brain, has been developed. JCDS is a software that creates a 3-dimentional head model of a patient by using CT and MRI images and that generates a input data file automaticly for calculation neutron flux and gamma-ray dose distribution in the brain by the Monte Carlo code: MCNP, and that displays the dose distribution on the head model for dosimetry by using the MCNP calculation results. JCDS has any advantages as follows; By treating CT data and MRI data which are medical images, a detail three-dimensional model of patinet's head is able to be made easily. The three-dimensional head image is editable to simulate the state of a head after its surgical processes such as skin flap opening and bone removal for the BNCT with craniotomy that are being performed in Japan. JCDS can provide information for the Patient Setting System to set the patient in an actual irradiation position swiftly and accurately. This report describes basic design and procedure of dosimetry, operation manual, data and library structure for JCDS (ver.1.0)

Vectorization, parallelization and porting of nuclear codes (vectorization and parallelization); Progress report fiscal 1999

Adachi, Masaaki*; Ishizuki, Shigeru*; Ogasawara, Shinobu*; Kume, Etsuo; Yatake, Yoichi*; Nemoto, Toshiyuki*; Kawasaki, Nobuo*; Kawai, Wataru*

JAERI-Data/Code 2000-043, 220 Pages, 2001/02

JAERI-Data-Code-2000-043.pdf:7.39MB

no abstracts in English

Vectorization, parallelization and porting of nuclear codes (Parallelization on scalar processors); Progress report fiscal 1999

Yatake, Yoichi*; Kume, Etsuo; Kawai, Wataru*; Nemoto, Toshiyuki*; Kawasaki, Nobuo*; Adachi, Masaaki*; Ishizuki, Shigeru*; Ogasawara, Shinobu*

JAERI-Data/Code 2000-038, 57 Pages, 2000/12

JAERI-Data-Code-2000-038.pdf:2.3MB

no abstracts in English

Vectorization, parallelization and porting of nuclear codes (Porting); Progress report fiscal 1998

Nemoto, Toshiyuki*; Kawasaki, Nobuo*; Kume, Etsuo; Kawai, Wataru*; Adachi, Masaaki*; Ishizuki, Shigeru*; Yatake, Yoichi*; Ogasawara, Shinobu*

JAERI-Data/Code 2000-017, p.99 - 0, 2000/03

JAERI-Data-Code-2000-017.pdf:3.31MB

no abstracts in English

Proceedings of the Workshop on Severe Accident Research held in Japan (SARJ-98); November 4-6, 1998, Tokyo, Japan

Sugimoto, Jun

JAERI-Conf 99-005, 523 Pages, 1999/07

JAERI-Conf-99-005.pdf:36.05MB

no abstracts in English