Pavlyshyn P. Improving the reliability of power valves

The valves on the NPP units occupy a special place, blocking the flows, regulating them, acting as safety equipment. The number of fittings on WWER-1000 units is large, about 9000 pcs. Failure of the valve can lead to very serious consequences, suffice it to mention the accident at the plant Three Mile Island. Thus, reliable trouble-free operation of armature guarantees reliable work of the main and auxiliary equipment. Given that the reliability of nuclear power plants is currently the most important task of power engineers around the world, this indicates the relevance of the chosen topic. Valves at power plants are very diverse, both in design and purpose, and in operating parameters. Working on large pressure drops on the surface of the valve seals is damaged by water erosion. To combat this phenomenon, try to design fittings that are resistant to erosion, but this is not always possible. The fittings are supplemented with stainless steel inserts, change the direction of flow, as well as change the material. And all the same at operation of difference more than 2,2 MPas there is an erosion wear. Thus, the development of erosion-resistant fittings is an urgent task for nuclear power plants. Another problem of NPP repair shops is the adjustment of the electric drive after repair. Improper adjustment will result in either the valve not being closed or the rod or bellows will break. In these cases, the fittings are also repaired. Solving these problems determines the relevance of this study.