New approach to handle neutron startup sources in a high temperature gas-cooled reactor

In a high temperature gas-cooled reactor, a neutron startup source (NS) cannot be handled simply. An appropriate transfer vessel, connected with a 241Am–Be source for startup core physics tests through an NS coupler and drive wire, was newly designed and installed in the high temperature engineering test reactor (HTTR). A result of tests using the HTTR revealed that the NS could be loaded simply and certainly into the reactor core through the transfer vessel below the allowable limit of effective dose equivalent for operators.