Izvestiya vuzov. Yadernaya Energetika

The peer-reviewed scientific and technology journal. ISSN: 0204-3327

Analysis of the defectiveness of the welds of №111 PGV 1000 and proposal on their elimination

4/04/2015 2015 - #01 Global safety, reliability and diagnostics of nuclear power installations

Povarov V.P.

DOI: https://doi.org/10.26583/npe.2015.1.03

UDC: 621.039

Reliability of planned and exploiting complex technical objects, such as AES – main condition of safety for the man and the environment. The basic factors, which influence reliability are: – absence of errors in design and calculation of constructions, the correctness of the selection of materials and technology of production; – quality of the materials used; – quality of assembly and welding works; – operating condition and operational control.

Despite the fact that with the design and the operation AES, clout is given to the guarantee of reliability, operating experience showed that in the welded joint of №111 PGV-1000M is possible crack formation. The mechanism of origin and increase in the cracks, until now, is not unambiguously determined.

In the article are represented the results of investigating the reasons for the damage of metal in the zone of the welded joint of № of 111 weldings of hot collector to the branch pipe Of du1200 of housing. The first case of the splitting of metal in the region of the connection of collector with the housing PG occurred in 1998 on 5 block Novovoronezh atomic station. Subsequently are discovered uniform damages even on several PG, which made it necessary to consider the cases of damage as the system problem, which has the general reasons.

To identify factors that lead to cracking, conducted a significant amount of R & d: analysis of the manufacture and properties of the metal; a detailed computational study of the stress state from operational factors; assessment of residual stresses from manufacturing techniques; experimental study of the stress state of the node models and the NPP; measurements and the analysis of the displacements of equipment RU with the thermal expansion; the determination of the critical dimension of cracks; the correction working of the working medium of secondary circuit; the exception of the thermo-shocks, connected with the work of the system of scavenging.

References

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discontinuity steam generator welded joint experimental studies