In service inspection and repair developments for SFRs
Abstract
Within the framework of large R&D studies performed since 2010 for future sodiumcooled reactors, with a first prototype called ASTRID, in-service inspection and repair (ISI&R) has
been identified as a major issue to be taken into account in order to improve the reactor’s safety, to
consolidate its availability and to protect its related investment.
Development, improvement and qualification of the ISI&R tools and processes for structures
immersed in sodium at about 200°C have been performed since early pre-conceptual design phase
of ASTRID This work is based on a set of consolidated specifications and a qualification process
involving increasingly more realistic experiments and simulations mainly performed with the Non
Destructive Examination CIVA code platform.
ISI&R items (in sodium telemetry and vision, Non Destructive Examination, Laser repair, associated
Robotics) are being developed and qualified as part of a multi-year program which mainly deals
with the reactor block structures and primary components, and sodium circuit with the power
conversion system.
This program is ensuring the strong ties needed between the reactor designers and inspection
specialists since the aim is to optimize inspectability and repairability. This has already induced
specific rules for design in order to shorten and facilitate ISI&R operations. These new rules have
been merged into the RCC-MRx rules in its first 2012 edition.
Current R&D deals with the following ISI&R items:
• Under-sodium non-destructive examination (NDE) of Stainless Steel thick welded joints:
specific ultrasonic transducers are developed and used for sodium testing, and associated
simulations are being performed.
• NDE of in-sodium welded joints, from outside of the main vessel (through the main vessel wall):
modeling, water testing and simulation are being performed..
• Under-sodium telemetry and vision of immersed structures and components: improved
techniques of short distance (less than 200mm) and far distance (up to some meters) scanning
are being studied. Water and sodium testing, and simulations are being performed.
• Methods for in-situ repair: a single laser technique has been selected for sodium sweeping
before machining and welding
• Associated in-sodium robotics: a sodium-proof material and technology is being developed and
tested. In sodium tight bell is looked at for repair application.
This paper is an up-dated version of the paper presented in 2015 at the ICAPP international
conference [1] and provides the main testing and simulation results for telemetry, vision and NDE
applications.
R&D for inspection and repair of SFRs faces challenging requirements and is progressing towards
available technological solutions, associated with demonstrated performance levels: the basic
inspection techniques are expected to reach level 6 of ‘technological readiness’ by the end of detailed
design phase: proof of principle with Pilot-scale, similar (prototypical) subsystem validation in
relevant environment.
The ‘integrated readiness level’ is also discussed in this paper with respect to access within the
reactor block, fluids, positioning and maintenance aspects.
Origin : Files produced by the author(s)
Loading...