| 2025 №11 (03) |
DOI of Article 10.37434/tpwj2025.11.04 |
2025 №11 (05) |
The Paton Welding Journal, 2025, #11, 28-34 pages
Features of the stressed state of welded absorber elements in the control and protection system of WWER-1000 during assembly and subsequent operation
O.S. Milenin, O.A. Velykoivanenko, H.P. Rozynka, O.O. Makhnenko
E.O. Paton Electric Welding Institute of the NASU. 11 Kazymyr Malevych Str., 03150, Kyiv, Ukraine. E-mail: asmilenin@ukr.netAbstract
The control and protection system (CPS) with absorber elements (AE) plays a key role in the stable and safe operation of WWER-1000 reactor, ensuring power regulation and emergency shutdown. The reliability of CPS AE directly depends on the integrity of the AE shell components, which are subjected to both welding stresses during assembly and to operational loads. A critical reliability factor for such structures is the stress-strain state at various stages of assembly and operation. This study focuses on the analysis of the SSS in the AE shell components caused by the technological phase of assembly welding and operational loading. Numerical modeling of thermodeformational processes shows that the geometric characteristics of the structure result in the fundamental difference in the stress distribution: a biaxial stressed state forms in the area where the cone is welded to the AE shell, and a triaxial stressed state develops in the zone where the tip is joined to AE shell. It is shown that during reactor emergency shutdown and cooling to room temperature, there is a significant drop in the external coolant pressure and a sharp increase in the maximum stresses within the AE shell wall, indicating an increased risk of integrity loss.
Keywords: nuclear reactor, WWER-1000, control and protection system, absorber elements, welded shells, stressed state, modeling
Received: Received: 10.06.2025
Received in revised form: 24.07.2025
Accepted: 19.11.202
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