Analysis of the defectiveness of the welds of №111 PGV 1000 and proposal on their elimination
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.
- Tehnicheskaya spravka TSAE AES OAO «VNIIAES» dlya soveschaniya-videokonferenсii konсerna Rosenergoatom 11.07.2013. Informaciya ob analogichnyh povtoryayuschihsya narusheniyah v rabote AES (k narusheniyu, proizoshedshemu 08.07.2013 na energobloke № 5 Novovoronezhskoj AES). Information similar repetitive NPP operational events -to a breach occurring July 08 2013 at power unit №5 Novovoronezh NPP).
- Tehnicheskij otchyot «Razrabotka, izgotovlenie, kalibrovka i otladka sistemy kompleksnogo monitoringa celostnosti metalla na osnovanii termodeformacionnoj nagruzhennosti zony karmana kollektora PG i momenta razvitiya defekta v zone SS №111 na polnomasshtabnom stende. Razrabotka tehnologii vypolneniya sbora dannyh sistemy kompleksnogo monitoringa termodeformacionnoj nagruzhennosti i momenta razvitiya treschiny (celostnosti) metalla korpusa PGV-1000 v zone svarnogo shva №111 privarki kollektora teplonositelya pervogo kontura k patrubku Du 1200» Technical report «Design, manufacture, calibration and debugging of complex monitoring system based on the integrity of the metal thermal loading of the deformation area pocket collector PG and since the development of a defect in the area of SS №111 on a full stand. Development of technology for performing data acquisition system integrated monitoring thermal deformation of loading and the date of the crack (integrity) of the metal body of PGV-1000 in the area of the weld welding №111 coolant reservoir 1-st loop to pipe DN 1200» ]. Moscow. OOO «NSUTS «TSMiR» Publ., 2011 (in Russian).
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