Preliminary investigation on capsule for low-temperature irradiation tests

Inaba, Yoshitomo  ; Ishida, Takuya; Onuma, Yuichi; Saito, Takashi

In order to carry out low-temperature irradiation tests under the high neutron flux in the JMTR core, desirable capsules were investigated from a survey and evaluation of current heat removal techniques. As a result, it was found that the low-temperature irradiation tests can be realized by the development of the capsule with cooling fins or the capsule using a boiling medium. In the case of the irradiation tests at about 100C, the capsule with the fins can be used, and the reactor cooling water cools the capsule including specimens. This technique has few subjects to realize. In the case of the irradiation tests at below 0C, the capsule using the boiling medium can be used, and the cooling of specimens in the capsule by liquid nitrogen is needed. In the present status, it is difficult that the liquid nitrogen is supplied to the capsule, and this technique has to overcome various subjects to realize. The investigation to solve these subjects will be carried out in the near future.