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영어

The Cold Neutron Research Facility(CNRF) is being built to produce a cold neutron which has peculiar physical property. In-Pool Assembly(IPA) was manufactured in a domestic factory, which is composed of moderator cell, heat exchanger, vacuum chamber, joint flange assembly and bracket etc. We had difficulties with the mechanical fabrication process due to the thin moderator cell. The special flange for the double flexible piping was developed. The tests of moderator cell, heat exchanger, vacuum chamber, double flexible pipe and IPA include the pressure test, normal temperature leak test and low temperature leak test. The moderator cell and heat exchanger were tested in the severe environmental condition and the burst tests of moderator cell were carried out. Above all, the bursting point took place at the area of the 0.01mm thinner place. It shows that the severe environmental test affects the bursting strength. The
double flexible pipe welding at the IPA top plate was related with the arrangement of moderator cell in the vacuum chamber. Therefore the connecting welding of the double flexible pipe linked to sequent of the vacuum piping, helium piping and hydrogen piping. The fabrication, test and assembling of cryogenic in radiation zone were developed.