Avtomaticheskaya Svarka (Automatic Welding), #3, 2021, pp. 10-16
Mathematical modeling of residual stresses in WWER-1000 elements after heat treatment
O.V. Makhnenko1, S.M. Kandala1, N.R. Basistyuk1, M.V. Cherkashin2
E.O. Paton Electric Welding Institute of the NAS of Ukraine.
11 Kazymyr Malevych Str., 03150, Kyiv, Ukraine. E-mail: firstname.lastname@example.org
«Ukrtsniitmash» Company, 7a Vasylenka Str., 03124, Kyiv, Ukraine. E-mail: email@example.com
Determination of residual life and extension of safe operating life of WWER-1000 internals for a term of up to 60 years
beyond the design period is an important scientific and engineering objective for nuclear power industry of Ukraine. During
long-term operation the internal elements: reflection shield and cavity are exposed to intensive impact of damaging radiation
dose that causes the processes of radiation embrittlement, swelling and creep in the material (austenitic steel 08Kh18N10T).
Technological residual stresses after welding and subsequent heat treatment should be taken into account at calculation-based
substantiation of the safe operating life of reactor internal elements. In the work mathematical modeling was used to derive
residual stress distributions in the volume of the reflection shield and internal cavity after electroslag welding and their
redistribution fields after post-weld heat treatment by autenitizing mode. It is determined that the residual welding stresses
are largely relaxed during austenitizing. In the reflection shield, however, which is of complex geometry with a variable wall
thickness and cooling channels, high residual stresses develop, due to occurrence of a significant temperature gradient at
cooling during austenitizing. These stresses should be taken into account at determination of the residual life of WWER-1000
internals. Ref. 8, Fig. 8.
WWER-1000, reactor internals, reflection shield, internal cavity, electroslag welding, heat treatment, austenitizing,
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