Treated water of The Tokai Reprocessing Plant used for cooling water and fire fighting water, is supplied by the steel pipes. These pipes are laid down under the ground or in the trench. Treated water had leaked, because the part of the underground pipe flange corrosion. The cause of this breakage was presumed that the pipe flange has been loaded the stress continuously. The stress generated depend of that the underground pipes sank with the ground subsidence by influence of the 2011 earthquake of the ...
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Adaptation of the Treated Water Pipe Maintenance Technology useing Clamp

Corroded pore was found at stainless pipe for liquid waste solution fro m the analytical laboratory. In order to find out the cause of corrosio , analytical samples were prepared cutting from the pipe. Reagents con ined chloride, which had been used analytical laboratory more than te years before the date, were found to be the trigger of the localized c rosion. We checked up all the pipes, which have been wasted including chloride solutions, by phased array instrument. We report the investig ion of cause o...
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Investigation into corrosion cause of the reprocessing facilities analysis waste fluid plumbing.

The air purge method is applied to measure a liquid level and its density of a radioactive solution in a tank in the okai reprocessing pla nt. In this method, air purge tubes soaked in nitric acid solution are often blocked bypositing salt of nitrate. Dried air is usually use d for the air purge system and this can be one of the reasons for enerating salt on the tube point. Therefore, a series of experiment usin g a humidifier to humidify the air has been erformed to prevent the blocking with salt, and the...
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Preventive countermeasure of air purge tube blocking using a humidifierin the Tokai Reprocessing Plant

Many rotating equipments, such as blowers and pumps, are installed in the Tokai Reprocessing Plant. Blowers are important to keep containment ability of nuclear materials in the plant. This work focuses on the function of the blowers as an object of the evaluation. MTTF(Mean Time To Failure) and failure ratio distribution of the configuration parts in the blower were obtained from the maintenance data based on 30-year experiences. The reliability of every parts in the blower was evaluated by calculating M...
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Development of maintenance technology for rotation equipments in the Tokai Reprocessing Plant I?Failure analysis for configuration parts of rotating equipment-

Rotating equipments, such as blowers and pumps, play an important role for securing safety of the Tokai Reprocessing Plant. Bearings in the rotating equipments are one of the important machine components for stable operation. The most important control item for the bearings management is to mainta in lubrication system any time. Oil slick thickness in the bearings can be quantitatively confirmed by the shock pulse method, though it was difficu lt with conventional vibration method to confirm it. This meth...
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Development of maintenance technology for rotation equipments in the Tokai Reprocessing Plant IIEquipment diagnosis by using the shock pulse method

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

1. 緒言平成21年4月に確認された東海再処理施設の海中放 出設備の漏えい事象は、漏えい箇所が海底埋設の放出 管であった。漏えいの原因は、放出管の施工時に損傷 し、経年変化として損傷箇所に電気防食で発生した水 素が影響したことで水素脆性割れが起こり、き裂が発 生、さらには水素誘起割れによりき裂が進展し貫通し たことによるものと推定した。損傷箇所に水素脆性割れが生じる原因となった水素 は電気防食によるものであり、このときの防食電位と 水素発生の関係等の調査を行った。この結果、損傷が 素が影響したことで水素脆......
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Liquid leakage from the sea release pipe of the Tokai reprocessing plant estigation into the cause of the leak (3): Preventive measures against recurrences and the management metho - Investigation into the cause of the leak (3): Preventive measures against recurrences and the management method

At the Tokai reprocessing plant, release of the low radioactive waste liquid to the ocean is carried out using sea release facilities. It was found that there was a leak point on the sea release facilities. Therefore, surveillance and confirmation were performed and the leak point was identified. The leak part was cut and the part was then collected to investigate the cause of the leak. As a result, it was estimated that the leak oc curred after the pipe was mechanically damaged and a successive metallurg...
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Liquid leakage from the sea release pipe of the Tokai reprocessing plant -Summary of ocean-releasing facilities and the leak phenomenon -

The automatic fire alarm system installed in the Tokai Reprocessing Plant consists of more than 5,000 detectors in about 40 facilities for the moment. In this system, 51 non-fire cases have occurred for about 8 years from January 2 001 to May 2009. and about half of these cases was due to the condensation of water vapor generated on the sensor. Therefore, the prevention of condensation is necessary to reduce such false alarms, and the measure for prevention o f condensation has been taken by installing a m...
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Prevention of False Alarms from Automatic Fire Alarm System in the Tokai Reprocessing Plant

There are plural facilities having a radiation controlled area in the Tokai reprocessing plant, and an interruptible power supply system which considered a blac kout is necessary for the power supply to eachility from the viewpoint of radiological management and nuclear material containment. In addition, at the ne of th e power supplying abnormality, intelligence gathering is necessary for prompt measures and toration. In this report, the intensive monitoring system, which aime d for the unification of the...
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The construction of an intensive monitoring system for power supply stations in the Tokai reprocessing plant