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Ishii, Takayuki; Isozaki, Kazunori; Ashida, Takashi; Minakawa, Satoru; Terakado, Tsuguo; Nogami, Hiroshi*; Kakurai, Katsuhiko*; Ueda, Soji*; Kawahara, Hirotaka; Ichige, Satoshi; et al.
JNC TN9410 2002-013, 86 Pages, 2002/11
JNC-TN9410-2002-013.pdf:68.29MB
The MK-III project has been proceeding to improve the irradiation capability of the experimental fast reactor JOY0. The MK-III project has three major purposes such as increase high neutron flux, improvement of plant availability factor and upgrading in irradiation techniques. Thermal output by core transformation for high neutron flux was increased from 100MWt to 140MWt. The main components in the cooling system such as IHX(Intermediate Heat Exchanger) and DHX(Dump Heat Exchanger) were replaced in MK-III modification in order to increase heat removal capability. Heat transfer capacity of IHX was increased from 50MWt/Unit to 70MWt/Unit and that of DHX was increased from 25MWt/Unit to 35MWt/Unit. These components replacement has been safety completed from october 30, 2000 through September 21, 2001. This report summarizes the way, results and safety measures about dismantling of no sodium adhered components and such as DHX blower and sodium cleaning of sodium components such as the DHX, the pipes connected with DHX and secondary side of IHX. Dismantling and sodium cleaning of secondary cooling system components were performed safely and efficiently as almost planned. The total amount of removed sodium was about 13.5kg.
; Ashida, Takashi; *; *; *; Isozaki, Kazunori;
JNC TN9450 2002-003, 52 Pages, 2002/05
JNC-TN9450-2002-003.pdf:6.24MB
The MK-III project has been proceeding to improve the irradiation capability of the experimental fast reactor JOYO since 1987. The MK-III project has three major purposes such as increasing high neutron flux, improvement of plant availability factor and upgrading in irradiation techniques. The increase of high neutron flux increased thermal output of core from 100MW to 140MW. The main components in the cooling system such as IHXs (Intermediate Heat Exchanger) and DHXs (Dump Heat Exchanger) were replaced in MK-III modification in order to increase heat removal capability. These components replacement has been safely carried out from october 30, 2000 to September 21, 2001. The radioactive corrosion products such as 
Co and 
Mn, and radioactive sodium were resided on the inner surface of old IHX which had been already removed from the system in the MK-III modification work. We may dismantle old IHX and remove the residual sodium only after enough decrease of their radioactivity. We have to store it safely over a fairly long Period. Therefore, we examined the safety storage way of old IHX. Based on the examination, we selected the free space inside the pump cleaning pit in the maintenance building as a radioactive waste storage facility. Before the modification work of pump cleaning pit, we needed the permission of design and the construction as well as the change of establishment for installation of radioactive waste storage facility. Modification work of the pump cleaning pit including removal of the interfering pipes were done for two months from April to May, 2000. Enlargement work of opening in pump cleaning pit and coating work of the wall surface were done from August, 2000 to January, 2001. Installation work of the metallic plate for shielding was done for two months from April to May of 2001 after installation of old IHXs in the pump cleaning pit. This report shows the records of installation of radioactive waste storage facility for ...