In the undergrounding pipe-space, there are many pipes for utility (electronic cable, water, gas, steam, etc.). These pipes are kept to safe by daily inspect ion. But hot environment of the pipe-space affects badly the device and a labor er's health.The investigation of the heat distribution was carried on, therefor e it was found that the radiant heat around the valve was very much. The method of thermal insulation was examined from the view point of the shape, cost, and effect. Then some of valves were ...
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The activities for improvement of hot environment in undergrounding pipe-space(trench)(1)The decrease of the radiant heat from steam pipe

There are 4-boiler in nuclear fuel cycle engineering laboratories( NCL). These boilers have been operated in the long term over 20 years. One of them, the leakage of boiler water was found at one of the generating tubes, and 2 adjoining generating tubes were corroded in Dec, 2011. These generating tubes were investigated by immersion ultrasonic testing (UT) for measure thickness of the tube. As a result, thinner tube was found in a part of a bend and near the water drum. These parts are covered with s...
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Maintenance of immersion ultrasonic testing on the water tube boiler

By evaluating the phenomena that hydrogen concentration of outlet gas in the off-gas treatment system at Hamaoka Unit 4 and 5 had increased, it was con cluded that the causes of the phenomena were transformation of support alumina by alteration of manufacturing process of catalysts and the deactivation by catalyst poisoning material. Therefore, the manufacturing process was modified and the poisoning material was identified and removed. Moreover, dev elopments such as catalyzer performance monitoring techn...
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Study of Degradation of Off-Gas H2/02 Recombination Catalyst at Hamaoka Unit 4 and 5 Hiroyasu OOSUMI

In the experimental fast reactor “Joyo”, it was confirmed that the top of the irradiation test sub-assembly of “MARICO-2” (material testing rig with temperature control) had been broken and bent onto the in-vessel storage rack as an obstacle and had damaged the upper core structure (UCS). This incident necessitated the replacement of the UCS and the retrieval of the MARICO-2 sub-assembly for “Joyo” restoration. This paper describes the in-vessel repair techniques for UCS replacement, which are develope...
英字タイトル:
Development of repair techniques in the reactor vessel of the experiment fast reactor “Joyo” - Replacement of Upper Core Structure -