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Watanabe, Tomoo; Ueda, Masashi; ; ; Terunuma, Seiichi

Saikuru Kiko Giho, (9), p.17 - 28, 2000/12

https://rdreview.jaea.go.jp/gihou/pdf2/5912.pdf

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Development of laser decontamination; Research and fundamental experiment

Fukui, Yasutaka; ; Tanimoto, Kenichi; Terunuma, Seiichi

PNC TN9410 95-041, 171 Pages, 1994/12

PNC-TN9410-95-041.pdf:11.32MB

As the material is irradiated by laser beam, its surface is instataneously heated and ablation. the contaminant in surface layer of radioactive wastes will be decontaminated, provided that such the physical phenomenon is used of decontamination technique. The applicability with decommissioning of laser decontamination technique are investigated by the research of the associated laser techniques and the removing test with metal surface. The results of the research and the test is as follows. (1)The research of laser decontamination. On the YAG and the eximer laser beam, there were some study reports of the decontamination, with the metal and the concrete. The structural material. the biological shield, and the waste strage vessel, these objects were regarded as the objects of the laser decontamination. (2)The removing test of the metal surfacc by lascr beam. The removing performance was examined by irradiating line forcused YAG laser beam with the stainless steel surface. The average removal depth rose, in proportion the product of the energy beam density and the number of beam pulse in He atomosphere. The removal depth was obtained more than 1m, in condition of the laser beam energy was 400mJ and the moving velocity of the test piece was 0.25mm/sec. About 65% of the ablation products were collected, by the simple absorbing system of the open type. (3)Future plan. It is necessary, Examining the removing performance and the variable property of the removal surface, investigating the decontamination technique of the large area and the collecting technique of the ablation products, and so. Thereafter the application to the decontamination will be studied.

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; Miyazaki, Hitoshi; ; Tanimoto, Kenichi; Terunuma, Seiichi

PNC TN9420 94-010, 103 Pages, 1994/04

PNC-TN9420-94-010.pdf:2.89MB

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Development of high-pressure ice brasting method (II) (Confirmation of most auitable condition for decontamination)

Fukui, Yasutaka; ; Tanimoto, Kenichi; Terunuma, Seiichi

PNC TN9410 94-033, 86 Pages, 1994/01

PNC-TN9410-94-033.pdf:33.14MB

It is must deceasse the pool risk for the radio active wastes. So it is necessary to decontaminate the wastes low level (500Sv/h) during control the secendry wastes. Exfoliation velocity (aria of exfoliated paint per unit time) was measured on various cndition changed parameter brasting pressure, feed rate, stand off distance between nozzle and waste surface, angle of nozzle, therefore most suitable condition for decontamination was decide on high-pressure ice brasting method, results are as follows. (1)Feeding dry-ice pellets of most suitable condition was decided on that brasting pressure is 15Kgf/cm, feed rate is 30%. Same exfolation ability was gained on condition that brasting pressure is 15Kgf/cm, feed rate is 50%. (2)Brasting dry-ice flow of most suitable condition was dicided on that stand off distance is between 50㎜ and 100㎜ angle of nozzle is 30 with vertical. (3)In case of a pipe form, exfolation ability was gained on condition that angle of nozzle is 60 with vertical after the waste was settled on the turn-table and turning. In case of angle iron form, on condition that angle of nozzle was 0 or 60 with vertical. In case of inner can on condition that angle of nozzle was 45 with axis. When these were such small parts as bolts in the barrel basket which leand 30 with vertical and turned 120rpm, exfolation ability was gained on condition that angle of nozzle was vertical. (4)In decontamination hood designing, negative pressure was maintaind in the cell, and freeze preventing heat capacity of ventilation filter (-78C) was calculated at 73kw.

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; Sumino, Kozo; Yasu, Tetsunori; ; ; ; Terunuma, Seiichi

PNC TN9410 91-376, 79 Pages, 1991/11

PNC-TN9410-91-376.pdf:1.9MB

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Terano, Toshihiro; ; Terunuma, Seiichi

PNC TN9410 91-325, 71 Pages, 1991/10

PNC-TN9410-91-325.pdf:1.74MB

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Operation experience report of experimental fast reactor JOYO; A special level monitoring for reactor vessel in the occurrance of the abnormal 1evel incident

; ; ; ; Ozawa, Kenji; ; Terunuma, Seiichi

PNC TN9410 91-187, 41 Pages, 1991/07

PNC-TN9410-91-187.pdf:1.0MB

A reactor vessel in JOYO provides three induction type level meters which is defined in the safety protection system. They have two kinds of measuring range and display the sodium level below to the discharge nozzle of the primary cooling system. One is from 350mm about the normal sodium level to 1,600mm below it and other two sets are from 350mm above to 350mm below it. This report describes a special monitoring method of sodium level in the occurrence of the abnormal sodium level incident which reaches it more than 1600㎜ below the normal sodium level in the reactor vessel. The special monitoring method uses the discharge sodium pressure of the primary auxiliary cooling pump. A discharge sodium pipe from the primary auxiliary cooling pump is located in the bottom of the reactor vessel and it's discharge pressure is correlated with the reactor vessel sodium level which works back pressure to the pump. Therefore, it was assumed that abnormal sodium level which reaches it more than 1600mm below the normal sodium level can be monitored using this discharge sodium pressure. A verification test was conducted to measure the correlation of the discharge sodium pressure and the reactor vessel sodium level. Main results obtained from this test were as follows. (1)Validity of this special level monitoring method was confirmed in the sodium level range from normal to 3,390㎜ below it and in case of sodium level changing which is decreased at the rate of 47.5m/h by this test during the system sodium drain work. (2)A correlation equation is obtained using parameters of discharge sodium pressure, flow and temperature of the primary auxiliary cooling system to gain sodium level of reactor vessel. (3)Parametor chart of the reactor vessel sodium level was made using multi regressive analysis.

The 7th annual inspection experience of experimental fast reactor JOYO; Operational management experience during the 7th annual inspection

*; *; *; Usui, Masahiro*; *; *; Terunuma, Seiichi*

PNC TN9410 89-099, 95 Pages, 1989/05

PNC-TN9410-89-099.pdf:3.28MB

This report described plant operational management during the 7th annual inspection of Experimental Fast Reactor JOYO from September 1988 to January 1989. One of the important purposes of this inspection is to find a rationality inspection method for LMFBR plants. Therefore, almost inspection items with various modifications and preparation for irradiation were completed for about 3.5 months. This is the shortest record on JOYO. The inspection schedule was very tight and complicated, but it was successfully finished in cooperation with members of operation and maintenance section, by adequate operational management and advanced preparation for inspection. Useful operational management techniques for rationality inspection were obtained, through the experience of 7th annual inspection.

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Terunuma, Seiichi

International Topical Meeting on the Safety,Statu, , 

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Abe, Sadayoshi; Terunuma, Seiichi; *

Proceedings of International Conference on Fast Reactors and Related Fuel Cycles, , 

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