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Journal Articles

A Modelling study on water radiolysis for primary coolant in PWR

Mukai, Satoru*; Umehara, Ryuji*; Hanawa, Satoshi; Kasahara, Shigeki; Nishiyama, Yutaka

Proceedings of 20th International Conference on Water Chemistry of Nuclear Reactor Systems (NPC 2016) (USB Flash Drive), 9 Pages, 2016/10

In Japanese PWR, the concentration of dissolved hydrogen in the primary coolant is controlled in the range from 25 cc/kg-H $_{2}$ O to 35 cc/kg-H $_{2}$ O for suppression of water decomposition. However this concentration is desired to reduce for the purpose of radiation source reduction in Japan. So, the concentration due to water radiolysis in primary coolant was evaluated at lower hydrogen concentration by the water radiolysis model in consideration of ray, fast neutron and alpha ray due to the reaction $^{10}$ B(n,) $^{7}$ Li. The results of evaluation showed that the water radiolysis was suppressed even if the hydrogen concentration was decreased to 5 cc/kg-H $_{2}$ O. The effects of the different G-value and the rate constants of major reaction on the concentration of H $_{2}$ O $_{2}$ and O $_{2}$ were studied under hydrogen addition. We also focused on the effect of the alpha radiolysis in boron acid water.

JAEA Reports

Data report of ROSA/LSTF experiment TR-LF-07; Loss-of-feedwater transient with primary feed-and-bleed operation

Takeda, Takeshi

JAEA-Data/Code 2016-004, 59 Pages, 2016/07

JAEA-Data-Code-2016-004.pdf:3.34MB

The TR-LF-07 test simulated a loss-of-feedwater transient in a PWR. A SI signal was generated when steam generator (SG) secondary-side collapsed liquid level decreased to 3 m. Primary depressurization was initiated by fully opening a power-operated relief valve (PORV) of pressurizer (PZR) 30 min after the SI signal. High pressure injection (HPI) system was started in loop with PZR 12 s after the SI signal, while it was initiated in loop without PZR when the primary pressure decreased to 10.7 MPa. The primary and SG secondary pressures were kept almost constant because of cycle opening of the PZR PORV and SG relief valves. The PZR liquid level began to drop steeply following the PORV full opening, which caused liquid level formation at the hot leg. The primary pressure became lower than the SG secondary pressure, which resulted in the actuation of accumulator (ACC) system in both loops. The primary feed-and-bleed operation was effective to core cooling because of no core uncovery.

Journal Articles

Study of radiation-induced primary process by ion pulse radiolysis

Yoshida, Yoichi*; Yang, J.*; Kondo, Takafumi*; Seki, Shuhei*; Kozawa, Takahiro*; Tagawa, Seiichi*; Shibata, Hiromi*; Taguchi, Mitsumasa; Kojima, Takuji; Namba, Hideki

JAEA-Review 2005-001, TIARA Annual Report 2004, p.183 - 185, 2006/01

https://jopss.jaea.go.jp/pdfdata/JAEA-Review-2005-001-p0127-p0267.pdf

A heavy-ion-pulse radiolysis technology was developed using a single-photon-counting system. In the system, the ion beam was injected a thin scintillator before irradiating the sample. The light emitted from the scintillator by the ion irradiation was used as analyzing source to detect the absorption of primary species in water. Measurement of time-dependent absorption of hydrated electrons in water was achieved using the system, which demonstrates the usefulness of this technique.

Journal Articles

Present status of energy in Japan and HTTR project

Ogawa, Masuro; Nishihara, Tetsuo

Nuclear Engineering and Design, 233(1-3), p.5 - 10, 2004/10

https://doi.org/10.1016/j.nucengdes.2004.07.018

Times Cited Count：27 Percentile：83.68(Nuclear Science & Technology)

An amount of primary energy supply in Japan is increasing year by year. Much energy such as oil, coal and natural gas is imported so that the self-sufficiency ratio in Japan is only 20 % even if including nuclear energy. An amount of energy consumption is also increasing especially in commercial and resident sector and transport sector. As a result, a large amount of greenhouse gas was emitted into the environment. Nuclear energy plays the important role in energy supply in Japan. Japan Atomic Energy Research Institute (JAERI) has been carried out research and development of a hydrogen production system using a high temperature gas cooled reactor (HTGR). The HTTR project aims at the establishment of the HTGR hydrogen production system. Reactor technology of the HTGR, hydrogen production technology with thermochemical water splitting process and system integration technology between the HTGR and a hydrogen production plant are developed in the HTTR project.

JAEA Reports

Report on investigation of cause of crack at instrumentation pipe in JMTR; Results of vibration and stress analysis

Hanawa, Satoshi; Tachibana, Yukio; Iyoku, Tatsuo; Ishihara, Masahiro; Ito, Haruhiko

JAERI-Tech 2003-064, 25 Pages, 2003/07

JAERI-Tech-2003-064.pdf:2.84MB

On the 147cycle operation, the water leakage was found at the pressure instrumentation pipe which is attached to the exit pipe of No.1 charge pump of the purification system of primary cooling system at JMTR in the Oarai establishment, JAERI. Then JMTR was shutted down manually on December 10th. It was predicted that the crack on the pressure instrumentation pipe was initiated and propagated by the cyclic load which was caused by the charge pump. Therefore, vibration and stress analyses of pressure instrumentation pipe were performed. From the vibration analysis, the natural frequency of the pressure instrumentation pipe of No.1 charge pump is between 5358Hz, which is close to the resonance frequency of 50Hz. From the stress analysis results, total stress generated on the pressure instrumentation pipe is 112.2MPa at the natural frequency of 53Hz and 74.2Mpa at 58Hz. It was found that the stress of 112.2MPa is close to the fatigue limit of used materials.

JAEA Reports

Report on investigation of cause of crack at instrumentation pipe in JMTR; Data book on examination of pressure instrumentation pipe at JMTR hot laboratory

Working Group for Investigation of Cause of Crack Initiation

JAERI-Tech 2003-060, 183 Pages, 2003/07

JAERI-Tech-2003-060.pdf:55.37MB

On December 10, 2002, the water leakage was found at the pressure instrumentation pipe attached to the exit pipe of No.1 charging pump of the purification system of a primary cooling system at JMTR, and the cracks were detected on the pressure instrumentation pipe by the visual observation. The Investigation Committee for Water Leakage from Instrumentation Pipe in JMTR was established and organized by specialists from inside and outside JAERI on December 16. In order to investigate the cause of crack initiation at the pressure instrumentation pipe, the Working Group was organized in the Department of JMTR. Visual inspection, fractgraphy test, metallographic observation and hardness test for the pressure instrumentation pipe and its weldment were carried out in the JMTR Hot Laboratory. This report summarized above data obtained by investigation on the cause of the crack initiation.

JAEA Reports