Determination of Probability of Failure of 20mnmoni55 Reactor Pressure Vessel Steel at Cryogenic Temperatures Using Beremin’s Model of Cleavage Fracture

Abstract

The Nuclear Energy is of much importance in current scenario of World energy requirements, and also it is cleaner energy source than its current competitive mass Energy Production Techniques. Most of the nuclear energy being produced for peaceful purposes is obtained from nuclear plants which operate on Nuclear Fission process. Reactor Pressure Vessel (RPV) is an important part of such Nuclear Plants. In most Indian Nuclear Reactors the Steel used for fabrication of RPVs is German Steel designated as 20MnMoNi55, which is also used in current study. A large number of specimens are tested on various cryogenic temperatures to simulate the embrittlement caused by radiation from reactor and also embrittlement caused by Loss of Coolant Accident (LOCA). Under such circumstances it is important to know the cleavage fracture characteristics of the material, thus for this purpose the cleavage fracture behavior of material is predicted using Beremin’s model of cleavage fracture, for this Weibull Stress (σu) and corresponding probabilities of failure (Pf) at different temperatures were determined in the current study.