The self-powered detector simulation 'MATiSSe' toolbox applied to SPND for severe accident monitoring in PWRs - 06163

In the framework of the ANR DISCOMS project, the feasibility of a remote corium migration monitoring in the unlikely event of a severe nuclear accident is considered and simulated. The corium progression is monitored by means of an instrumented pole equipped with self-powered neutron detectors (SPNDs) and a thermocouple. A rhodium and a platinum emitter SPNDs are encapsulated in this instrumented pole. Their performances have been calculated using the numerical tool called MATiSSe for different SPNDs locations. MATiSSe toolbox simulation results provide SPND currents that demonstrate the proposed instrumented pole capabilities. Its adequate positioning is on the reactor vessel side and on the reactor concrete basemat. These configurations would allow the monitoring of the corium progression towards the concrete basemat in case of a severe nuclear accident. The full monitoring equipment is planned to be tested during a joined CEA-THERMOCOAX experimental campaign in some realistic irradiation conditions in the Slovenian TRIGA Mark II reactor. (authors)