Results of shielding performance test in rise-to-power test of the HTTR

Ueta, Shohei   ; Takada, Eiji*; Sumita, Junya ; Shimizu, Atsushi ; Ashikagaya, Yoshinobu; Umeda, Masayuki; Sawa, Kazuhiro

In the radiation shielding design of the High Temperature Engineering Test Reactor (HTTR), strong attention is needed to avoid especially upward neutron streaming. Shielding performance test have been carried out in the Rise-to-power test up to full power operation of 30MW. The measured dose equivalent rates in unrestricted area were lower than the detection limit for neutron-ray, and background level for -ray. The neutron dose equivalent rate measured in the stand pipes room was about 120Sv/h at full power operation, which was much lower than the shielding design (330 mSv/h) and the prediction (10 mSv/h).