The French Atomic and Alternative Energy Commissariat has been tasked with the design of a fourth generation fast neutron reactor. The neutron flux measurement instrumentation for this future reactor will be based on fission chambers placed in the reactor housing. These “high temperature” fission chambers should be able to function at full power at temperatures between 400 and 600°C. In collaboration with the chamber manufacturer, Photonis, a recent review of the present-day chamber technology has revealed that there are certain issues to be addressed in order to assure reliability for operation at these higher temperatures. In particular, it shall be necessary to have a better comprehension of partial discharges which can occur in the chambers. These discharges lead to current impulsions which are not discernable from those caused by fission, giving false positive detection of neutrons. In addition, they can lead to accelerated aging of the chamber’s ceramic insulators. Work in progress at Supélec on electrical discharges along insulator surfaces in argon at atmospheric pressure has shown behavior remarkably different from that predicted by the well-known empirical “Paschen Law”. Using both theoretical and experimental approaches, the objective of this thesis is to find an explanation for this phenomenon. The thesis will be managed jointly by CEA, Supélec, and Photonis.

This position is open until it is filled.

Département: DM2I (LIST)
Laboratory: Laboratoire Capteurs et Architectures Electroniques
Start Date: 01-10-2015
ECA Code: SL-DRT-15-0821
Contact: hassen.hamrita<στο>cea.fr