Hot Helium Leak Test of ITER blanket shield block

Abstract

To ensure successful operation of the International Thermonuclear Experimental Reactor (ITER), the blanket shield block modules are required to demonstrate the vacuum performance by Hot Helium Leak Test (HHLT), which is performed at the relevant ITER operational conditions and is one of the Factory Acceptance Tests (FAT) of the product. A specific facility is developed in China to perform these demanding tests, which has a 10 m3 vacuum chamber to accommodate the large size of shield blocks and achieved an overall system leak detect sensitivity of 7.19 × 10−11Pa. m3/s at 235 °C. A full-scale proto-type of ITER shield block was tested in this facility, which showed maximum helium leak rate is less than 1.74 × 10-10Pa. m3/s under 4.2 MPa pure helium gas pressure at 235 °C. The HHLT was performed with cyclic pressure and temperature process and the results were given in this paper. The behavior of the background leak rate during these processes were also monitored and discussed.