Inspection and repair techniques in the reactor vessel of the experimental fast reactor Joyo; Development of cover gas recycling system with precise pressure control

Ushiki, Hiroshi*; Okuda, Eiji; Suzuki, Nobuhiro; Takamatsu, Misao; Nagai, Akinori

JAEA-Technology 2015-042, 37 Pages, 2016/02

JAEA-Technology-2015-042.pdf:16.51MB

The reactor vessel of a sodium-cooled fast reactor (SFR) is filled with sodium coolant and cover gas (argon gas). In case of a cover gas boundary open (ie., in-vessel repair), installation of a temporary cover gas boundary and controlling the cover gas pressure slightly positive are required to prevent the cover gas release and the contamination of impurities, and during upper core structure (UCS) replacement in the experimental SFR Joyo from March to December 2014, a vinyl bag was installed as a part of the temporary cover gas boundary. However, because it has inferior thermal resistance, supply a cooling gas too much was required to maintain proper temperature for two months. On the basis of this requirement, a cover gas recycling system with precise pressure control was developed and adopted for UCS replacement. The system has a good pressure controllability and recyclability. The successful results of this system contributed to the certain promotion of UCS replacement. In addition, the insights and the experience gathered in this development are expected to improve the in-vessel repair techniques in sodium-cooled fast reactors.

Inspection and repair techniques in reactor vessel of sodium cooled fast reactor, 9-1; Program summary of Joyo restoration work

Ito, Hideaki; Maeda, Yukimoto; Yoshida, Akihiro; Takamatsu, Misao; Sekine, Takashi

no journal, , 

no abstracts in English