New material exploration to enhance neutron intensity below cold neutrons; Nanosized graphene flower aggregation

Teshigawara, Makoto; Ikeda, Yujiro*; Yan, M.*; Muramatsu, Kazuo*; Sutani, Koichi*; Fukuzumi, Masafumi*; Noda, Yohei*; Koizumi, Satoshi*; Saruta, Koichi; Otake, Yoshie*

Nanomaterials (Internet), 13(1), p.76_1 - 76_9, 2023/01

https://doi.org/10.3390/nano13010076

To enhance neutron intensity below cold neutrons, it is proposed that nanosized graphene aggregation could facilitate neutron coherent scattering under particle size conditions similar to nanodiamond. It might also be possible to use it in high neutron radiation conditions due to graphene's strong sp2 bonds. Using the RIKEN accelerator-driven compact neutron source and iMATERIA at J-PARC, we performed neutron measurement experiments, total neutron cross-section, and small-angle neutron scattering on nanosized graphene aggregation. The measured data revealed, for the first time, that nanosized graphene aggregation increased the total cross-sections and small-angle scattering in the cold neutron energy region, most likely due to coherent scattering, resulting in higher neutron intensities, similar to nanodiamond.

Research on the state-of-the-art of accident consequence analysis method for non-reactor nuclear facilities, 1

Yoshida, Kazuo; Abe, Hitoshi; Yamane, Yuichi; Tashiro, Shinsuke; Muramatsu, Ken

JAEA-Research 2007-047, 70 Pages, 2007/06

JAEA-Research-2007-047.pdf:5.63MB

Japan Atomic Energy Agency (JAEA) entrusted with a research on the state-of-the-art of consequence analysis method for Probabilistic Safety Assessment (PSA) of non-reactor nuclear facilities (NRNF) such as fuel reprocessing and fuel fabrication facilities to the Atomic Energy Society of Japan (AESJ). The objectives of this research is to obtain the basic useful information related for establishing the quantitative performance requirement and for risk-informed regulation through qualifying issues needed to be resolved for applying PSA to NRNF. A special committee of "Research on the analysis methods for accident consequence in NFRF" was organized by the AESJ. The research activities of the committee were mainly focused on the analysis method for upper bounding consequences of accidents such as events of criticality, explosion, fire and boiling of radioactive solution postulated in NRNF resulting in release of radio active material to the environment. This report summarizes the results of research conducted by the committee in FY 2006.

Research on the state-of-the-art of probabilistic safety assessment for non-reactor nuclear facilities (I)

Yoshida, Kazuo; Abe, Hitoshi; Yamane, Yuichi; Tashiro, Shinsuke; Muramatsu, Ken

JAEA-Research 2006-085, 81 Pages, 2007/02

JAEA-Research-2006-085.pdf:5.42MB

Japan Atomic Energy Agency (JAEA) entrusted with research on the state-of-the-art of probabilistic safety assessment (PSA) for non-reactor nuclear facilities (NRNF) to the Atomic Energy Society of Japan (AESJ). The objectives of this research is to obtain the basic useful information related for establishing the quantitative performance requirement and for risk-informed regulation through qualifying issues needed to be resolved for applying PSA to NRNF. A special committee of "research on the analysis methods for accident consequence in NFRF" was organized in the AESJ. The research activities of the committee were mainly focused on the analysis method for upper bounding consequences of accidents such as events of criticality, explosion, fire and solvent boiling postulated in NRNF resulting in release of radio active material to the environment. This report summarizes the result of research conducted by the committee in FY 2004.

Polarizance of a synthetic mica crystal polarizer and the degree of linear polarization of an undulator beamline at 880eV evaluated by the rotating-analyzer method

Imazono, Takashi; Hirono, Toko*; Kimura, Hiroaki*; Saito, Yuji; Ishino, Masahiko; Muramatsu, Yasuji*; Koike, Masato; Sano, Kazuo*

Review of Scientific Instruments, 76(12), p.126106_1 - 126106_4, 2005/12

https://doi.org/10.1063/1.2140492

Polarizance of a reflection-type polarizer made with a synthetic mica (fluorophlogopite) single crystal was evaluated at the photon energy of 880 eV by means of the rotating-analyzer method in conjunction with the evaluation of the degree of linear polarization of the insertion beamline, SPring-8 BL23SU, featuring an APPLE-2 type variably polarizing undulator. When the undulator was tuned to the horizontal linear polarization mode, the maximum reflectances for s- and p-polarization for a symmetric Bragg reflection of synthetic mica(002) were 2.6% and 0.013%, respectively, at incident angles of near 45. Our analysis based on the rotating-analyzer method gave the polarizance of the polarizer of at least 0.997 0.002 and the degree of linear polarization of 0.993 0.004 in the linear polarization mode.

Hazard analysis approach with functional FMEA in PSA procedure for MOX fuel fabrication facility

Tamaki, Hitoshi; Yoshida, Kazuo; Watanabe, Norio; Muramatsu, Ken

Proceedings of International Topical Meeting on Probabilistic Safety Analysis (PSA '05) (CD-ROM), 11 Pages, 2005/00

A probabilistic safety assessment (PSA) procedure for Mixed Oxide (MOX) fuel fabrication facilities is being developed applicable to nuclear facilities at Japan Atomic Energy Research Institute (JAERI). As part of the PSA procedure, the approach to hazard analysis was established, which consists of two analysis steps: Functional Failure Modes and Effects Analysis (Functional FMEA) and Risk Matrix Analysis. In the Functional FMEA, a variety of functions of equipment composing the facility are analyzed to identify potential abnormal events exhaustively. In the second step, these potential events are screened to select abnormal events as candidate events to be analyzed for frequency and consequence by using two-dimensional matrix based on the rough estimation of likelihood and maximum unmitigated release of radioactive material. The applicability of the hazard analysis approach established was demonstrated through the trial application of the PSA procedure being developed to model plant of MOX fuel fabrication facility.

Polarization performances of mica crystal polarizers in 1-keV region

Imazono, Takashi; Hirono, Toko*; Kimura, Hiroaki*; Saito, Yuji; Muramatsu, Yasuji*; Sano, Kazuo*; Ishino, Masahiko; Koike, Masato

no journal, , 

An experimental evaluation for the state of polarization of soft X-ray in the 1-keV region between 0.7 and 1.9 keV has not been performed because there is no polarizing element suitable for this energy region. In order to evaluate the state of polarization of polarized soft X-ray in the 1-keV region, we have developed a reflection-type polarizer by use of fluorophlogopite mica crystal which has the lattice constant of approximately 1 nm and can be made large single-crystal in these days. The polarization performance of fluorophlogopite mica was evaluated by the rotating-analyzer method at the BL23SU beamline, which was tuned to horizontal linear polarization mode, of SPring-8. As the result, the reflectance for s- (p-) polarization and the polarizance of fluorophlogopite(002) was 2.6% (0.013%) and 0.998 at the incident angle of 45.02 at 0.88 keV, respectively. This indicates that fluorophlogopite mica works the high efficient reflection-type polarizer. Using it, the degree of linear polarization of the incident light at 0.88 keV was determined. The polarization performances of muscovite and phlogopite micas are also mentioned.

Preparation of equipment failure rate for a reprocessing facility, 3; Examination of applicability of existent equipment failure rate

Tamaki, Hitoshi; Yoshida, Kazuo; Ishida, Michihiko; Muramatsu, Ken; Ueda, Yoshinori*

no journal, , 

no abstracts in English

A New standard of systematic procedures for risk assessment of nuclear fuel

Yoshida, Kazuo; Takebe, Kazumi*; Manabe, Fumitoshi*; Takahashi, Yoshiyuki*; Muramatsu, Ken*

no journal, , 

Efforts of developing methodologies and basic data for risk assessment are undertaken actively for NFFs in Japan. However, a systematic procedure for conducting risk assessment to achieve appropriate quality and reasonable cost that are commensurate with the risk of each facility has not been developed. Therefore, the Subcommittee on Risk Assessment of Nuclear Fuel Facilities newly organized under the Standard Committee, developed a new standard for systematic procedures for risk assessment of NFF s, which allows the users to select appropriate optional methods depending on the risk levels of their facilities.