Development of Procedures of Leak Before Break Assessment for Sodium Cooled Fast Reactor

Double-Ended-Guillotine-Break(DEGB) in pipes can be prevented by detecting a leakage that occurs at the through-wall stage of a crack opening under those conditions. A consideration of these LBB characteristics can enlarge the degree of design freedom with respect to the materials, piping layouts, and safety measures against a leakage, thus leading to improved plant reliability and economy. For the LBB assessment of SFR pipes, creep crack growth could be considered, because SFRs are operated above 500 .deg. C. But the LBB assessment procedure for high temperature has not been established yet. In this study, we analyze RCC-MR A16 and propose procedure for the LBB assessment based on RCC-MR A16. For verification of this procedure, we conduct an example of LBB assessment. And we found partial procedure, equation and constant that has not been provided in RCC-MR A16. In this study, LBB assessment procedure has been proposed for SFRs design based on RCC-MR A16. Also, proposed procedure was verified by conducting an example assessment. As a result of those draw two conclusions as follow: · The LBB assessment of SFRs can be conducted by proposed procedure based on RCC-MR A16. · However, it is needed to develop determination of critical crack length methodology