GRS develops a probabilistic analysis tool PROST (PRObabilistic STructure calculation) for the determination of structural reliability of piping and vessels. This program development allows the calculation of leakand break probabilities for various geometries, load assumptions, material properties and crack assumptions with consideration of uncertainties in form of distribution functions. With the developed prototype the leak- and break probabilities can be determined as function of the operating time taking into account the damage mechanism “fatigue” on the basis of a two-parametric fracture mechanics failure criterion.

Furthermore, a module was developed taking into consideration the damage mechanism “corrosion”, especially inter-granular stress crack corrosion with austenitic materials and strain-induced crack corrosion with ferritic materials. Additionally, an available method for leak rates calculations have been included into the program, because leak detection has a noteworthy influence on the break probability, since measures can be taken into consideration due to indications of leak monitoring systems installed in nuclear power stations. The application range of the code was extended to complex geometries in regards to loading and boundary conditions by additional code modules to include the results of finite element (FE) calculations.