Analytical-Experimental Substantiation of the Operability of Localizing Safety System Element Seals of WWER Power Units

Abstract

The relevance of this work is determined by the need to predict the operation of seal assemblies for localizing safety system (LSS) elements of  WWER power units, which include penetrations, hatches, airlocks, doors, and other elements of the sealed enclosure (SE) in operating modes. Operating modes are understood as normal operation modes, abnormal conditions, and emergency situations. During the manufacture and operation of LSS elements, the problem arises of uneven protrusion of a two-row rubber gasket from the grooves in the LSS element web, which leads to the need to clarify the integral compression force of the seal as a whole for this element. The problem is caused by the imperfection of the technology for manufacturing large webs for LSS elements (doors, hatches, and airlocks: the perimeter of the seals can reach 10–20 m, the web diameter is 2–6 m) and the need to maintain strict technological requirements for flatness, parallelism, and tolerance extremes in linear and angular dimensions. The manufacture of large structures is complicated by the presence of welded joints, heat treatment, and the complexity of metalworking. The compression force of the PNAE-7-002-86 rubber gasket is not regulated; therefore, for the reliable design of seal compression mechanisms, the magnitude of this force is determined. Based on the results of rubber gasket tests for tightness and cyclic loading, an assessment of the tightness of the used rubber gaskets has been performed and calculations of the rubber gasket deformations have been performed using the FEM software package. Recommendations have been developed to increase the reliability of seal assemblies for LSS elements of WWER power units in operating modes and to select the compression for the required force to provide tightness at the commencement of operation and after 5000 open/close cycles.