Conclusions of the Leak Before Break analysis project for the V-2 NPP

The major results of the Leak Before Break (LBB) analysis for the Bohunice V-2 NPP are given. The structure of the report is as follows: (i) Static and dynamic calculations; (ii) Database of fracture mechanical properties; (iii) Database of corrosion properties; (iv) Evaluation of the fatigue damage and crack propagation; (v) Stability of heavy component supports; (vi) Water impact shock assessment; (vii) Steam generator and pressurizer integrity; (viii) Leak measurement and diagnosis; (ix) LBB Handbook; (x) Critical component evaluation by the finite element method; and (xi) Evaluation of experiments on actual scale models. The following recommendations follow from the conclusions: (1) The entire primary circuit pipeline 500 mm i.d. can be granted the LBB statute. (2) The two bottom branches of 200 mm i.d. from the primary circuit pipeline 500 mm i.d. to the pressurizer can be granted the LBB statute. (3) The seismic reinforcement of the primary pipeline 500 mm i.d. and of the following components: reactor pressure vessel, main circulation pump, steam generator, pressurizer, and the two pressurizer branches, can be qualified as sufficient for an earthquake of magnitude 8 on the MSK-64 scale. (4) Swing limiters against the dynamic effects of a chopping cut into the pipe and protection against the shooting-up medium need not be installed. (5) The probability of damage of the above safety-related pipeline systems is extremely low, in the order of 10-6/reactor.year. (6) No cut-out of the primary pipeline 500 mm i.d. as assumed by the inspection plan needs to be made in 100 000 hours of operation. (J.B.). 39 tabs., 43 figs., 92 refs