EVALUATION OF THE REMAINING LIFE OF COLLECTORS AND STEAM GENERATORS OF UNITS NOS. 5 AND 6 OF THE KOZLODUI NUCLEAR POWER STATION IN BULGARIA WITH ALLOWANCE

摘要

The problem of the determination of the remaining life of steam generators has become especially important after the detection of defects in collectors fabricated from steel 10GN2MFA in some Russian nuclear power stations (NPS). An experimental and computational study has shown that the life of collectors is determined to a considerable extent by the level of residual process stresses after the explosive pressing of the pipes and by the plasticity of the material in the aqueous medium. Most NPS units in the CIS countries and Bulgaria have been produced with the use of explosive spreading of pipes into the collector wall.The aim of the present work is to evaluate the remaining life of the collector of steam generators of units Nos. 5 and 6 of the Kozlodui NPS in Bulgaria with allowance for the special features of their service.