Present status and future plan of HTTR project

The HTTR project aims at demonstrating inherent safety features of High temperature gas-cooled reactors (HTGRs) by safety demonstration tests, and establishing nuclear heat utilisation technology by a hydrogen production demonstration test. The safety demonstration tests are divided to the first phase and second phase tests. In the first phase tests, simulation tests of anticipated operational occurrences and anticipated transients without scram are conducted. The second phase tests will simulate accidents such as a depressurisation accident (loss of coolant accident). The first phase safety demonstration tests have been carried out during FY 2002-2005, and the second phase tests are planned to start in FY 2006. A hydrogen production facility will be connected to the HTTR for the hydrogen production demonstration test to establish the coupling technology such as well as the procedure on safety design and evaluation. The coupling technology consists of safety-related one such as countermeasures against explosion of combustible gas and tritium permeation from helium gas to process gas and so on, and control ones for preventing thermal mismatch between reactor and hydrogen production facility. This report describes the present status and the future plan of the HTTR project.