If a serious accident occurs on a nuclear installation (PWR, experimental reactor, fuel cycle installation, etc.) in France, the IPSN activates its Technical Crisis Center (CTC) if requested to do so by the safety authority. The purpose of this document is to present the organization and means of the CTC used to deal with an accident situation affecting a fuel cycle installation. This document thus starts by describing the missions of the CTC, and then goes on to describe the methods of triggering the alert, the organization and defined skills, relations set up with the operator, the technical expertise procedure and evaluation means that have been developed.