Ultimate strength assessment of penetrated nuclear reactor containment vessel subjected to external pressure and thermal loads

Abstract

For nuclear-power ships or submarines, the mechanical penetration assemblies (MPAs) installed on the nuclear reactor containment are designed to withstand extreme loadings caused by high pressures and temperatures. The ultimate strength of the MPAs should be adequately predicted for the safety of reactor containment. An analysis approach has been developed to assess the ultimate strength of MPAs under external pressure and thermal load. Based on the equivalent method, the analysis method is validated by the theoretical formula and experimental data of the cylindrical shells. Then, the influences of geometry, environmental temperature and thermal stress on the ultimate strength of the MPAs are discussed. An ultimate strength assessment relationship of the MPA subjected to external pressure and thermal loads is also proposed based on the analysis results. The proposed approach and suggested relationship can drastically facilitate future MPA design from the point of view of ultimate strength.