PURPOSE: To prevent occurrence of an abnormal situation by employing a double wall structure for a plurality of cooling channels having cooling boards, inserting a thermal conduction member composed of a braided mesh wire between the walls there of and secured in place, detecting the cooling water leaked between the walls and removing the heat, thereby preventing the cooling water from intruding directly into a vacuum vessel due to damage of the cooling channel.
CONSTITUTION: A plurality of cooling channels 8 having cooling boards 9 employs double wall structure having inner and outer walls 10a, 10b and a braided mesh wire 11 is inserted between the inner and outer walls 10a, 10b and secured in place. Even if the inner wall 10a is damaged due to aging or deterioration in the strength of material caused by conduction of heat from the armor tile 4, the cooling water leaks to the air gap of the braided mesh wire 11 between the inner and outer walls 10a, 10b and direct intrusion into a vacuum vessel 2 is blocked by the outer wall 10b. Furthermore, the damaged part can be specified by providing each cooling board 9 with a moisture gauge or a vacuum gauge for detecting the leakage of cooling water.
SEKI MASAHIRO
TADA EISUKE
KOIZUMI KOICHI
FUKUSHIMA HISASHI
ITO KOJI
SHIBUI MASANAO
TOSHIBA CORP