Instrumentation and in-service inspection in the ASTRID project: main objectives and considered solutions

摘要

On the basis of available feedback and the new safety requirements, the ISI&R for instrumentation, in service inspection and repair, has been identified as a major issue for next Sodium cooled Fast Reactor prototype ASTRID. Indeed, ISI&R is strongly involved in safety analysis, in economy reliability, and in investment protection. The safety objective for the ASTRID project is threefold: a) a level of safety that it is at least equivalent to the 3rd generation reactors, b) integration of the defence-in-depth principle and c) a better safety demonstration than previous SFR. For the instrumentation, the objectives are mainly the improvement of the in-operation continuous monitoring and the protection against accidents, for the whole plant. That means: 1. better diversification and redundancy to take into account events which were not considered in the past; 2. up to date technologies; 3. specific post-accidental instrumentation. For ISI&R, the main axes remain: 1. improvement of the primary system conceptual design, 2. development of measurement and inspection techniques 3. accessibility and associated robotics, 4. development and validation of repair processes. The ASTRID strategy is supported by the French R&D program for ISI&R improvement and industrial developments in the frame of specific ASTRID agreements based on several aspects: ensuring a strong connection between the reactor designers and inspection specialists, and developing tools and techniques which must be operated in a sodium environment (monitoring up to 550°C and inspection at 200°C). The aims of an ambitious R&D program are: 1. Validation for high temperature fission chambers manufacturing used in order to detect several incidents and monitor the reactor operation, 2. Validation of ultrasonic transducers (US telemetry and NDE sensors) under sodium conditions, 3. Definition of key components of the robotic equipment for operation in sodium, 4. Preliminary validation of repair processes and techniques (cleaning, machining and welding). Associated ISI&R needs are being defined through an iterative method between designers and instrumentation specialists: adaptation of the Design to ISI&R requirements, validation of the ultrasonic and chemical transducers, of ultrasonic non destructive simulation, of acoustic surveillance, of laser repair intervention processes, of connected robotic equipment. This paper summarizes the main orientations of the project and gives a few examples of the work carried out by CEA and its industrial partners.