Effect of magnesium silicate hydrate (M-S-H) formation on the local atomic arrangements and mechanical properties of calcium silicate hydrate (C-S-H); In situ X-ray scattering study

Kim, G.*; Im, S.*; Jee, H.*; Suh, H.*; Cho, S.*; Kanematsu, Manabu*; Morooka, Satoshi; Koyama, Taku*; Nishio, Yuhei*; Machida, Akihiko*; et al.

Cement and Concrete Research, 159, p.106869_1 - 106869_17, 2022/09

https://doi.org/10.1016/j.cemconres.2022.106869

Estimation of exchange time for neutron startup sources of HTTR

Ono, Masato; Kozawa, Takayuki; Fujimoto, Nozomu*

JAEA-Technology 2019-012, 15 Pages, 2019/09

JAEA-Technology-2019-012.pdf:2.83MB

The High Temperature Engineering Test Reactor has a neutron source of Cf to start up the reactor and to confirm count rates of wide range monitors. The half-life of Cf is short, about 2.6 years, so it is necessary to replace at an appropriate time. In order to estimate the period to replace, it is necessary to consider not only the half-life but also the fluctuation of the count rate of the wide range monitor to prevent alarm. For that reason, the method has been derived to predict a minimum count rate from relationship between the count rate and the standard deviation of the count rate of the wide range monitors. As a result of predicting the count rate using this method, it was found that the minimum count rate reaches to 3.0cps in 2022 and 1.5 cps in 2024. Therefore, it is necessary to exchange Cf by 2024.

The Measurements of neutron energy spectrum at 180 degrees with the mercury target at J-PARC

Matsuda, Hiroki; Meigo, Shinichiro; Iwamoto, Hiroki

Journal of Physics; Conference Series, 1021(1), p.012017_1 - 012017_4, 2018/06

https://doi.org/10.1088/1742-6596/1021/1/012017

Spallation neutron at 180 degrees is of important for an evaluation of radiation protection for ADS (Accelerator-Driven System) and the nuclear physics. It was, however, quite difficult to measure it. We measured the energy spectrum of spallation neutron at 180 degrees at the proton transport beam line (3NBT) to MLF (Materials and Life Science Experimental Facility) on J-PARC by the NE213 liquid scintillator. The irradiated proton energy was 3 GeV, and the intensity was 110 protons above. The neutron energy was determined by Time-Of-Flight method with n-gamma discrimination. We also simulated the energy spectrum by using PHITS code and compared with measured spectrum. In this paper, the overview of the experiment and the results are described.

Benchmark study on realized random packing model for coated fuel particles of HTTR using MCNP6

Ho, H. Q.; Morita, Keisuke*; Honda, Yuki; Fujimoto, Nozomu*; Takada, Shoji

Proceedings of 2017 International Congress on Advances in Nuclear Power Plants (ICAPP 2017) (CD-ROM), 8 Pages, 2017/04

Development of the prediction technology of cable disconnection of in-core neutron detector for the future high-temperature gas-cooled reactors

Shimazaki, Yosuke; Sawahata, Hiroaki; Kawamoto, Taiki; Suzuki, Hisashi; Shinohara, Masanori; Honda, Yuki; Katsuyama, Kozo; Takada, Shoji; Sawa, Kazuhiro

Journal of Nuclear Engineering and Radiation Science, 2(4), p.041008_1 - 041008_5, 2016/10

https://doi.org/10.1115/1.4032597

Maintenance technologies for the reactor system have been developed by using the high-temperature engineering test reactor (HTTR). One of the important purposes of development is to accumulate the experiences and data to satisfy the availability of operation up to 90% by shortening the duration of the periodical maintenance for the future HTGRs by shifting from the time-based maintenance to condition-based maintenance. The technical issue of the maintenance of in-core neutron detector, wide range monitor (WRM), is to predict the malfunction caused by cable disconnection to plan the replacement schedule. This is because that it is difficult to observe directly inside of the WRM in detail. The electrical inspection method was proposed to detect and predict the cable disconnection of the WRM by remote monitoring from outside of the reactor by using the time domain reflectometry and so on. The disconnection position, which was specified by the electrical method, was identified by non-destructive and destructive inspection. The accumulated data is expected to be contributed for advanced maintenance of future HTGRs.

Development of the prediction technology of cable disconnection of in-core neutron detector for the future high-temperature gas cooled reactors

Shimazaki, Yosuke; Sawahata, Hiroaki; Kawamoto, Taiki; Suzuki, Hisashi; Shinohara, Masanori; Honda, Yuki; Katsuyama, Kozo; Takada, Shoji; Sawa, Kazuhiro

Proceedings of 23rd International Conference on Nuclear Engineering (ICONE-23) (DVD-ROM), 7 Pages, 2015/05

Maintenance technologies for the reactor system have been developed by using the high-temperature engineering test reactor (HTTR). One of the important purposes of development is to accumulate the experiences and data to satisfy the availability of operation up to 90% by shortening the duration of the periodical maintenance for the future HTGRs by shifting from the time-based maintenance to condition-based maintenance. The technical issue of the maintenance of in-core neutron detector, wide range monitor (WRM), is to predict the malfunction caused by cable disconnection to plan the replacement schedule. This is because that it is difficult to observe directly inside of the WRM in detail. The electrical inspection method was proposed to detect and predict the cable disconnection of the WRM by remote monitoring from outside of the reactor by using the time domain reflectometry and so on. The disconnection position, which was specified by the electrical method, was identified by non-destructive and destructive inspection. The accumulated data is expected to be contributed for advanced maintenance of future HTGRs.

Nodal arrangements for boundary treatment in EFGM

Tian, R.; Nakajima, Norihiro; Yagawa, Genki

Keisan Kogaku Koenkai Rombunshu, 10(1), p.397 - 400, 2005/05

An attempt is made to treat boundary conditions in EFGM through only nodal arrangements. One of major merits of the proposed nodal arrangement scheme is its straightforwardness in implementation. The accuracy of this nodal arrangement boundary treatment and its influence on convergence are assessed by comparing with the Lagrange multiplier and penalty methods using one- and two- dimensional problems. The nodal arrangement scheme shows a same performance as the Lagrange multiplier and penalty methods in the one-dimensional tests, but it evidently outperforms the penalty method in the two-dimensional tests.

Development of PVB film for low-dose dosimetry in radiation processing

Solomon, H. M.*; Kojima, Takuji

Nucleus, 33, p.16 - 20, 2005/00

Low-dose dosimeters were developed based on the mixture films of polyvinyl butyral (PVB) and the acid-sensitive dye leucomalachite green (LMG). Chloral hydrate (RX) was added to the mixture for enhancement of the radiation sensitivity of the film dosimeters. Different film dosimeter materials were prepared using 9.07 10mole LMG per one gram PVB with various RX:LMG molar concentration ratio. The dosimeter response, which is expressed in terms of change in absorbance at 628 nm per unit thickness, increased linearly with dose and RX concentration. The PVB-LMG dosimeter system, in which the ratio of RX concentration to that of LMG is higher than 10, show measurable dose range of 1-100 Gy for Co -rays.

Electron-beam-induced fries rearrangement and oxidation reactions of sulfonic acid esters in crystalline state

Yuasa, Kanako; Enomoto, Kazuyuki*; Maekawa, Yasunari; Kato, Jun*; Yamashita, Takashi*; Yoshida, Masaru

Journal of Photopolymer Science and Technology, 17(1), p.21 - 28, 2004/07

https://doi.org/10.2494/photopolymer.17.21

The electron beam (EB)-induced reactions of arylsulfonic acid esters, phenyl p-toluenesulfonate (1a), phenyl benzenesulfonate (1b), and phenyl 1-naphthalenesulfonate (1c), were examined in the balk state. The EB irradiation of 1a afforded the Fries rearrangement products, o- and p-hydroxyphenyl p-tolylsulfones (2a and 3a), phenol (5), and the oxidation product of 2a, o,p-dihydroxyphenyl p-tolylsulfone (4a), which has not been observed in photolysis. The irradiation of 1b, which is liquid at room temperature, gave Fries products, 5, and the oxidation product, o,p-dihydroxyphenyl phenylsulfone. On the other hand, the EB-induced reaction of 1c proceeded with the lowest reactivity through crystal to crystal transformation to afford Fries products and 5, but not oxidation product. The mechanistic study reveals that oxidation product 4a generated by the oxidation reaction of ortho-Fries product 2a but not para-isomer 3a with an active oxidant, which should result from the decomposition of 1a.

A New approach for three-dimensional atomic-image reconstruction from a single-energy photoelectron hologram

Matsushita, Tomohiro*; Agui, Akane; Yoshigoe, Akitaka

Europhysics Letters, 65(2), p.207 - 213, 2004/01

https://doi.org/10.1209/epl/i2003-10074-6

A "scattering pattern matrix" method is proposed here to overcome the difculties presented by photoelectron holography, such as forward-scattering and multi-energyproblems. This method makes it possible to reconstruct a three-dimensional atomic arrangement from a single-energy hologram. We have utilized the "scattering pattern matrix" that includes the angular variation of the scattered object waves, and we have adopted a specialaverage process and the gradient projection method for minimizing the mean-squared error. The reconstruction of the Si bulk structure is demonstrated by using an experimental Si(111) 2s single-energy hologram.