The steam generator tubes in a PWR (Pressurized Water Reactor) are constituents of
the containment barrier of the reactor coolant system, and the
requirement for their integrity corresponds to a fundamental nuclear
Thanks to the international Tube Integrity Program (TIP-5) led by the US NRC and carried out at the experimental level by Argonne National Laboratory (ANL), IRSN will further develop its expertise in the mechanical strength of these tubes, the processes involved in their degradation and specific monitoring techniques.
Steam generator tubes serve to transfer heat from the reactor coolant in the primary system, which is heated by the nuclear fuel to temperatures of over 300° C, to the secondary system to produce the steam required to generate electricity. To achieve optimum heat transfer between the two systems, the walls of the nickel-based metal alloy tubes are relatively thin, about 1 mm. It is important to ensure that the mechanical strength of these tubes is maintained to prevent any ruptures that may lead to leakage of radioactive water from the reactor coolant system.
In response to this objective, a large part of the TIP-5 program is devoted to non-destructive testing applications, in particular to evaluate the performance of the probes used throughout the world to detect defects inside the tubes.
Based on the results of these investigations, IRSN will be able to position itself as regards the probes used in France and, if appropriate, recommend avenues for improving both the equipment and the operating procedures.
The experimental data on corrosion cracking phenomena in steam generator tubes developed by ANL and supplied to IRSN will enable the Institute to improve its assessment of the results of monitoring carried out by EDF. It will also help validate a digital model of the simulation platform that IRSN uses for its assessments.
In addition to NRC, ANL and IRSN, five other agencies participating in the program : CNSC (Canadian Nuclear Safety Commission) , US EPRI (Electric Power Research Institute) , Canadian AECL (Atomic Energy of Canada Limited) , KAERI (Korea Atomic Energy Research Institute) , KINS (Korea Institute of Nuclear Safety).