Radioactive materials in nuclear plants are confined in the facility at a negative pressure less than atmospheric pressure, which is maintained by the ventilation system. Therefore, it is important for nuclear safety to keep the negative pressure an d to monitor the condition of the ventilation system. Also, immediate maintenance is essential when the ventilation system fails. In the Tokai Reprocessing Plant, monitoring the negative pressure in the facilities and the condition of the ventilatio n system is...
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Negative Pressure Monitoring and Maintenance Management of theVentilation System in the Tokai Reprocessing Plant

In the ventilation facilities of the Tokai reprocessing plant, particle filters are generally installed both in air-intake nd exhaust systems. In the air-intake system, atmospheric dust is filtered and the cleaned air is supplied into adiation control led areas, whereas in the exhaust system, radioactive materials are filtered and it is discharged to thevironment. Because the filter of the exhaust system serves to prevent radiological release to the environment, a igh-efficiency particle air (HEPA) filter ...
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Optimization of the exchange period of high efficiency particulate air filter in Tokai Reprocessing Plant

The two dissolvers installed in the Tokai Reprocessing Plant had failed occurred successively in 1982 and 1983. Then, remote-controlled equipment for repair and inspectio n has been developed because the dissolvers were installed under the high radiation condition and cannot access easily. After repair of the dissolvers, the periodic inspe ction by remoteness is periodically carried out once per year for soundness confirmation of the vessels. Moreover, the remote inspection equipment for periodic inspectio...
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Development of the Remote Inspection Equipment for the Enriched Uranium Dissolvers

The nitric acid solution dissolving nuclear fuel material is transferred with the three way valve called VCV (VCV: vide-casse- vide in Fr.) using vacuum in the Tokai Reprocessing Plant. The initial VCV was not reliable because it had broken with in 1 or 2years. The cause of failure was damage of the plastic diaphragms in the moving parts. Then, the new VCV valve with stainless- steel bellows was developed. There is no failure in moving parts in 20years, therefore reliability is significantly improved....
英字タイトル:
Development of new three way valve using vacuum for liquid transfer