Development of Tools, Instrumentation and Codes for Improving Periodic Examination and Repair of SFRs

Abstract

In the frame of the CEA, EDF, and AREVA coordinated research program launched in 2007 for the development of Generation IV sodium-cooled fast reactors (SFRs), the improvement of in-service inspection and repair (ISI&R) capabilities was identified as a major issue. Within the French-associated multiannual SFR research program, the periodic examination and repair are looked at through the following main R&D axes: (i) improvement of the primary system conceptual design in order to ease periodic examination and repair, (ii) development of inspection techniques (periodic inspection tools and associated simulation), (iii) accessibility and associated robotics, and (iv) development and validation of repair processes. Associated needs are being defined through an iterative method between designers and inspection specialists: adaptation of the SFR design to ISI&R requirements, validation of the ultrasonic transducers, of associated ultrasonic nondestructive examination techniques, of laser repair processes, of associated robotic equipment. International collaboration is also running for some specific items such as ultrasonic visualization under liquid sodium.

Multi-modal leaky Lamb waves in two parallel and immersed plates: Theoretical considerations, simulations, and measurements

“…Well adapted to this harsh environment, ultrasonic solutions are being studied for the inspection of the main vessel and different parts of ASTRID. The immersion of specific ultrasonic transducers in liquid sodium is currently being investigated (Baqu e et al, 2012). However, it appears that inspection operations performed with a transducer located outside the main vessel (in the inter-vessel gap filled with gas) have shown promising potential (Baqu e et al, 2011;Corneloup et al, 2011).…”

Temperature Resistant Fiber Bragg Gratings for On-Line and Structural Health Monitoring of the Next-Generation of Nuclear Reactors

“…The use of “hot” sodium as a coolant to control the temperature of the fission reaction within fast reactors and thus to prevent damage to the core, has triggered the development of innovative sensing solutions able to operate in such a severe and specific environment [ 6 ]. Considering that: (i) sodium coolant is opaque; (ii) sodium needs to be operated at a nominal temperature of 580 °C; (iii) this temperature may reach 700 °C in the case of a severe accident situation and not decrease below 97.72 °C (sodium’s melting temperature), any in situ sensing techniques have to be designed in order to withstand high temperatures over an extended period of time without any maintenance and to be sodium compatible.…”

“…Several innovative solutions have been considered in order to provide tools for on-line monitoring of fast reactor nuclear cores. These are not limited to acoustic and ultrasonic sensors, inspection robots, fission chambers, laser-based spectroscopy techniques for pile gas composition analysis, radiation-hardened thermocouples [ 6 ] but also encompass optical fiber sensors [ 7 , 8 , 9 , 10 ]. Sensors probing the nuclear core from outside the pool are ideal (ultrasonic sensors) but not always possible.…”

Study of Lamb Waves for Non-Destructive Testing Behind Screens

“…1 shows different inspection strategies with ultrasonic transducers inside and outside the main vessel. Immersion of specific ultrasonic transducers in liquid sodium is under study [3], [4] (1 st strategy in Fig. 1).…”