Initialising ...
Initialising ...
Initialising ...
Initialising ...
Initialising ...
Initialising ...
Initialising ...
March, 2000); Shinohara, Kunihiko; ; ; ; Isozaki, Tokuju; ; *
JNC TN8440 2000-003, 93 Pages, 2000/08
The investigation on the radioactivity concentration for gross beta, 
H and 
Cs in seawater collected around the discharge point had been performed in order to grasp the change of the activity level of the coastal seawater offshore the JNC Tokai Works from the low level liquid effluent of the reprocessing plant. After the investigation on the radioactivity in seawater during the hot examination, the detailed investigation on the environmental effects from the liquid effluent of JNC reprocessing plant has been performed since July 1978 on the basis of the request from Ibaraki prefecture as the full-scale operation of the reprocessing plant. Consequently, no increase of the radioactive concentration due to the discharged effluent has been observed. And also, as the result of the consideration to the investigation on the environmental effect from the liquid effluent throughout 22 years since 1978, no change of the radioactive concentration level in seawater was recognized.
Omori, Eiichi; ; ; ; Maki, Akira; Yamanouchi, Takamichi
JNC TN8410 2000-003, 93 Pages, 1999/10
JNC-TN8410-2000-003.pdf:4.92MB
Radioactive materials in aqueous solution at a nuclear fuel reprocessing plant causes radiolytic generalion of several gases including hydrogen. Hydrogen accumulating in equipment can be an explosion hazard. In such plants, though the consideration in the design has been fundamentally made in order to remove the ignition source from the equipment, the hydrogen concentration in the equipment should not exceed the explosion threshold. It is, therefore, desired to keep the hydrogen concentration lower than the explosion threshold by diluting with the air introduced into equipment, from the viewpoint which previously prevents the explosion. This report describes the calculation of hydrogen generation, evaluation of hydrogen concentration under abnormal operation and consideration of possible improvement at Tokai Reprocessing Plant. The amount of hydrogen generation was calculated for each equipment from available data on radiolysis induced by radioactive materials. Taking into consideration for abnormal condition that is single failure of air supply and loss of power supply, the investigation was made on the method for controlling so that the hydrogen concentration may not exceed the explosion threshold. Possible means which can control the concentration of hydrogen gas under the explosion threshold have been also investigated. As the result, it was found that hydrogen concentration of most equipment was kept under the explosion threshold. It was also shown that improvement of the facility was necessary on the equipment in which the concentration of the hydrogen may exceed the explosion threshold. Proposals based on the above results are also given in this report. The above content has been described in "Examination of the hydrogen produced by the radiolysis" which is a part of "Review of Design Data for Safety Assessment of Tokai Reprocessing Plant" (JNC TN8410 99-002) published in February 1999. This report incorporates the detail evaluation so that operation ...
Togawa, Orihiko; Homma, Toshimitsu
Proc. of the 3rd Int. Conf. on Nuclear Fuel Reprocessing and Waste Management: RECOD91,Vol. 1, p.253 - 258, 1991/00
no abstracts in English
Togawa, Orihiko; Homma, Toshimitsu
Proc. of the CSNI Specialist Meeting on Safety and Risk Assessment in Fuel Cycle Facilities, p.351 - 360, 1991/00
no abstracts in English