Development of irradiation rig in HTTR and dosimetry method; I-I type irradiation equipment

Shibata, Taiju ; Kikuchi, Takayuki; Miyamoto, Satoshi*; Ogura, Kazutomo*

The HTTR aims to establish and upgrade the technological basis for the HTGRs and to perform the innovative basic research on high temperature engineering. The HTTR is planned to be used to perform various tests such as, the safety demonstration test, high temperature test operation and irradiation test with large irradiation fields at high temperatures. This paper describes the design of the I-I type irradiation equipment, developed as the first rig for the HTTR, and does the planned dosimetry method at the first irradiation test. It was developed to perform in-pile creep test on a stainless steel with large standard size specimens. It can give great loads on the specimens stably and can control the irradiation temperature precisely. The in-core data are measured by differential transformers, thermocouples, SPNDs and neutron fluence monitors. The obtained data at the first test can be contributed to upgrade the technological basis for the HTGRs, since it is the first direct measurement of the in-core irradiation environments.