Upgrade of the small-angle neutron scattering diffractometer SANS-J at JRR-3

Kumada, Takayuki; Motokawa, Ryuhei; Oba, Yojiro; Nakagawa, Hiroshi; Sekine, Yurina; Micheau, C.; Ueda, Yuki; Sugita, Tsuyoshi; Birumachi, Atsushi; Sasaki, Miki; et al.

Journal of Applied Crystallography, 56(6), p.1776 - 1783, 2023/12

https://doi.org/10.1107/S1600576723009731

The combination of the existing position-sensitive photomultiplier and the 3He main detector with focusing devices, and the newly installed front detectors in SANS-J at JRR-3 covers small-angle neutron scattering signals in the range of the magnitude of the scattering vector Q from 0.002 to 6 nm-1 gaplessly with three standard device layouts. The installation of the front detector and a graphical user interface system largely improved the usability of SANS-J.

Polarized neutrons observed nanometer-thick crystalline ice plates in frozen glucose solution

Kumada, Takayuki; Nakagawa, Hiroshi; Miura, Daisuke; Sekine, Yurina; Motokawa, Ryuhei; Hiroi, Kosuke; Inamura, Yasuhiro; Oku, Takayuki; Oishi, Kazuki*; Morikawa, Toshiaki*; et al.

Journal of Physical Chemistry Letters (Internet), 14(34), p.7638 - 7643, 2023/08

https://doi.org/10.1021/acs.jpclett.3c01448

The structure of nano-ice crystals in rapidly frozen glucose solution was elucidated by using spin-contrast-variation small-angle neutron scattering, which distinguishes the nano-ice crystal signal from the frozen amorphous solution signal by the polarization-dependent neutron scattering. The analysis revealed that the nano-ice crystals form a planar structure with a diameter exceeding tens of nanometers and a thickness of 1 nm, which is close to the critical nucleation size. This result suggests that the glucose molecules are preferentially bound to a specific face of nano-ice crystals, and then block the crystal growth perpendicular to that face.

Development of spin-contrast-variation neutron powder diffractometry for extracting the structure factor of hydrogen atoms

Miura, Daisuke*; Kumada, Takayuki; Sekine, Yurina; Motokawa, Ryuhei; Nakagawa, Hiroshi; Oba, Yojiro; Ohara, Takashi; Takata, Shinichi; Hiroi, Kosuke; Morikawa, Toshiaki*; et al.

Journal of Applied Crystallography, 54(2), p.454 - 460, 2021/04

AA2020-0724.pdf:2.05MB

https://doi.org/10.1107/S1600576721000303

We developed a spin-contrast-variation neutron powder diffractometry technique that extracts the structure factor of hydrogen atoms, namely, the contribution of hydrogen atoms to a crystal structure factor. Crystals of L-glutamic acid were dispersed in a dpolystyrene matrix containing 4-methacryloyloxy-2,2,6,6,-tetramethyl-1-piperidinyloxy (TEMPO methacrylate) to polarize their proton spins dynamically. The intensities of the diffraction peaks of the sample changed according to the proton polarization, and the structure factor of the hydrogen atoms was extracted from the proton-polarization dependent intensities. This technique is expected to enable analyses of the structures of hydrogen-containing materials that are difficult to determine with conventional powder diffractometry.

Structural investigation of sulfonated polyphenylene ionomers for the design of better performing proton-conductive membranes

Shiino, Keisuke*; Otomo, Toshiya; Yamada, Takeshi*; Arima, Hiroshi*; Hiroi, Kosuke; Takata, Shinichi; Miyake, Jumpei*; Miyatake, Kenji*

ACS Applied Polymer Materials (Internet), 2(12), p.5558 - 5565, 2020/11

https://doi.org/10.1021/acsapm.0c00895

Hydrogen absorption and desorption on Rh nanoparticles revealed by dispersive X-ray absorption fine structure spectroscopy

Song, C.*; Seo, O.*; Matsumura, Daiju; Hiroi, Satoshi*; Cui, Y.-T.*; Kim, J.*; Chen, Y.*; Tayal, A.*; Kusada, Kohei*; Kobayashi, Hirokazu*; et al.

RSC Advances (Internet), 10(34), p.19751 - 19758, 2020/05

https://doi.org/10.1039/D0RA03322G

The R&D goal of Monju

Hiroi, Hiroshi*; Arai, Masanobu; Kisohara, Naoyuki

Dai-21-Kai Doryoku, Enerugi Gijutsu Shimpojiumu Koen Rombunshu (USB Flash Drive), 3 Pages, 2016/06

The purpose of fast breeder reactors (FBR) and the role of Monju were discussed in Ministry of education, culture, sports science and technology-Japan (MEXT) after the Fukushima NNP accident. The discussion has concluded that FBRs contribute to energy security and reduction of high-level radioactive waste, and that Monju is to be utilized to demonstrate these usefulness and to implement international contributions. This paper addresses anticipated R&D results from Monju on the basis of the enforcement of new nuclear regulation, the energy situations in Japan and the international status of FBR development and collaborations.

The Development and Application of Overheating Failure Model of FBR Steam Generator Tubes (IV)

Miyake, Osamu; Hamada, Hirotsugu; Tanabe, Hiromi; Wada, Yusaku; Miyakawa, Akira; Okabe, Ayao; Nakai, Ryodai; Hiroi, Hiroshi

JNC TN2400 2003-003, 225 Pages, 2004/02

JNC-TN2400-2003-003.pdf:40.45MB

The model has been developed for the assessment of the overheating tube failure in an event of sodium-water reaction accident of fast breeder reactor's steam generators (SGs). The model has been applied to the Monju SG studies.

The development and application of overheating failure model of FBR steam generator tubes

Hamada, Hirotsugu; *; *; *; Hiroi, Hiroshi*

PNC TN9410 98-029, 122 Pages, 1998/05

PNC-TN9410-98-029.pdf:14.03MB

The following items have been studies to evaluate overheating failure of FBR generator heat transfer tubes: (1)To establish a structural integrity analysis method. The strength standard values for 2.25Cr-1Mo steel was established taking account of time dependent effect to overheating failure mechanism based on high temperature (700 - 1200C) creep data and was validated by tube rupture simulation test data. (2)To improve and validate blow down analytical method. The analytical result by use of BLOOPH, the FBR blow down code, was compared with that by use of RELAP-5, the general purpose thermo-hydraulic code, and a good agreement was obtained. (3)To quantitatively validate the entire overheating analysis model by sodium water reaction data Sodium-water reaction tests of SWAT-3 and LLTR were analyzed using above mentioned analytical method. The ductile fracture occurred earlier than the creep fracture in the analysis and the comparison of tube failure times with the experiments showed sufficient conservativeness. Based on the above studies, the analytical method was applied to PFR superheater leak event and the Monju steam generator accidental analysis. The followings were quantatitively shown through the analysis: (1)The most important cause that multi-tube failure occurred in the 1987 PFR superheater-2 leak is that the superheater did not equip a fast steam dump system at the time of the leak event. (2)Overheating failure will not occur under any operational conditions of Monju in both steady state and transient phases such as water/steam blow-down. (3)Although safety margin becomes small when the water/steam flow rate becomes small during the blow-down, the modification of the plant such as hastening blow-down by equipping more relief valves will drastically improve the safety margin.

Validation of ASSCOPS by results of large-scale demonstration test, Run-D2

; Matsuki, Takuo*; Hiroi, Hiroshi*; Himeno, Yoshiaki

PNC TN9410 88-092, 82 Pages, 1988/08

PNC-TN9410-88-092.pdf:4.29MB

Post-test calculations of the large-scale sodium leak demonstration test, Run-D2, were performed using the ASSCOPS code in order to validate the applicability of the code to the evaluation of the fire suppression function of the PNC-type smothering tank. In the analysis, radiation coefficients between aerosols in the gas phase and structures and a pool surface in the smothering tank defined in the code were varied as parameter. The following three cases were calculated. (a)No aerosols suspending was assumed in the gas phase and thus, 1.0 was used as the coefficient between the structures and the pool surface. (b)The coefficient between the aerosols and the pool surface was 0.65, and that between structures and the aerosols was 0.73. (c)The coefficient between the aerosols and the pool surface was the same as case (b) and 0.5 was used as that between structures and the aerosols. The comparison between analysis and experiment with regard to the temperature of the various parts showed that the agreement was within +30% and -20%. From these results, it was concluded that the code was available for the evaluation of the fire suppression function of the smothering tank.

Sodium fire test at broad ranges of temperatures and oxygen concentrations (1); Effect of leak patterns on ignition temperatures

Kawada, Koji*; ; Hiroi, Hiroshi*; Himeno, Yoshiaki

PNC TN9410 88-004, 44 Pages, 1988/01

PNC-TN9410-88-004.pdf:6.85MB

Since sodium leak and fire researches have been performed at high-temperatures simulating an accident during the rated reactor operation knowledge of sodium leak and fire at low-temperatures which may happen at Ex-vessel Storage Tank or during the partial power operation of the reactor was very li,ited. Therefore, the present test was carried out to clarify the ignition temperatures and the temperature at which aerosol starts to release during sodium spray, column, and pool fires. Sodium spray and column tests were conducted at Sodiu Fire Test Rig (SOFT-1), while sodium pool test was carried out at Sodium Leak Fire and Aerosol Test Rig (SOLFA-1). The following test results were obtained from these tests. (1)Sodium Spray Test. The ignition temperature was 160C depending upon the droplet diameter of sprayed sodium. (2)Sodium Column Test. (a)Sodium main flow did not ignite, while the scattered sodium droplets ignited. (b)The ignition temperature of the main flow rebounded on a pan was 180C. (c)The ignition temperature of deposits on a pan was 160 C. (3)Sodium Pool Test. (a)The ignition temperature of the static pool ranged from 280 to 315C. (b)Temperature at which aerosol starts to release was determined to be 140 to 160C by visual in spection. (c)After extinguished artificially by closing a lid, sodium reignited at temperatures higher than 80 C when the lid was reopend.