SAFETY SCENARIO AND INTEGRATED THERMOFLUID TEST

The largest mobilizable radioactive material inventory in the form of tritium and activated dust in a fusion reactor is estimated to be loca ted in the vacuum vessel. The accident scenarios of postulated thermof luid transients such as ingress of coolant inside the vacuum vessel an d the loss of vacuum boundary leading to the release of radioactive ma terial are introduced. The accuracy of the present analysis method and database for evaluating the radioactive material release in such acci dent scenarios is assessed. The areas where the data and methods seem to be most uncertain are identified, such as the condensation of steam under vacuum condition, the activated dust mobilization and transport in and out of the vacuum vessel in the event of the transients. An ap proach to experimentally reduce such uncertainties in the evaluation o f radioactive material release are presented. A combination of a numbe r of specific test devices to reduce uncertainties in such areas as du st mobilization and transport, and an integrated thermofluid test faci lity to establish the evaluation methodology are proposed. (C) 1998 El sevier Science S.A. All rights reserved.