Reaktorszerkezeti anyagok hegesztett kötéseinek kisciklusú fárasztása

Szabó, Attila and Bereczki, Péter (2021) Reaktorszerkezeti anyagok hegesztett kötéseinek kisciklusú fárasztása. DUNAKAVICS, 9 (4). pp. 5-29. ISSN 2064-5007

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Abstract

The reactor vessel of Pressurized Water Reactors is a key equipment for the safe operation of a nuclear power plant. It operates at high pressure (12-15 MPa) and high temperature (250-325 °C) and includes the reactor core. Ensuring the structural integrity of the tank and associated pressure equipment and its welded joints is paramount throughout the life of the plant, as their integrity ensures that radioactive media do not escape uncontrolled outside the process and do not endanger plant workers, the public and the environment. Therefore, the reactor vessel must be able to withstand all loads resulting from the normal operating conditions of the reactor and possible malfunctions without damage. Although there are analyzes that demonstrate the technical feasibility of replacing the reactor vessel, it is considered a non-replaceable equipment from a management perspective. As mentioned above, the reactor vessel is the equipment of the nuclear power plant that designates the framework of the operating life. The equipment of a nuclear power plant includes a large number of welds and corrosion protection cladding made by welding, so in addition to understanding the properties of the base metal, it is at least as important to know the fatigue behavior of welded joints with significantly different structure than the base metal. In the energy industry, even the use of structures considered to be static varies greatly during start-up and shut-down, heating and cooling, and feeding hot or cold media. These additional mechanical stresses are often much higher than the design operating stress and often cause short-cycle fatigue. Most of the research in the literature has focused on fatigue at constant temperatures among nuclear power plant equipment. In these devices, not only stresses from internal pressure but also thermal stresses due to temperature gradients can reach significant intensities due to starts and stops and temperature fluctuations during operation, and the thermophysical properties of the structural material change significantly with temperature change. In a low-temperature fatigue test at constant temperature known from the literature, these effects were ignored. In our research, thermomechanical fatigue tests that better approximate real operating conditions make it possible to operate temperature cycles on the specimen in parallel with the mechanical cycles, so the actual load of the equipment can be more accurately modeled, thus the life expectancy of the reactor vessel and welded joints can be approximated more accurately

Item Type: Article
Uncontrolled Keywords: reaktortartály; hegesztési varrat; statikus üzem; fárasztóvizsgálat; reactor vessel; welding seam; static plant; fatigue test
Divisions: Műszaki Intézet
Depositing User: Gergely Beregi
Date Deposited: 04 May 2021 11:24
Last Modified: 04 May 2021 11:24
URI: http://publication.repo.uniduna.hu/id/eprint/754
MTMT: 31983500

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