The design basis accident of pressurised water reactor (PWR) nuclear power plant is the transient double-end fracture of reactor coolant system piping or the transient double-end fracture of two-loop system piping in the containment under the operation of dedicated safety facilities. This paper is based on ATHROC (Analysis of Thermal Hydraulic Response of Containment), an independently developed containment response analysis software developed by China Nuclear Power Engineering Corporation (CNPE), which is suitable for simulating the occurrence of a water loss accident, a main steam pipeline rupture accident, or a main feeder pipeline rupture accident in a nuclear power plant. The software is suitable for modelling the pressure and temperature increase in the compartments of a containment plant following a water loss accident, a main steam pipe rupture accident or a main feed pipe rupture accident, due to the release of mass energy from the rupture, as well as for modelling the mitigation effect of dedicated safety facilities. A classical pressurised water reactor (PWR) accident scenario is analysed and compared with the results of the same type of software: PAREO, GOTHIC, in order to validate the accuracy of the ATHROC software calculations and the reliability of the software when applied to advanced nuclear power plant projects.