The passive containment cooling system (PCCS) is one main component of the various passive safety systems in the advanced 3rd generation pressurized water reactor. Several containment analysis codes are modified for the simulation and analysis on the PCCS by researchers. These codes for the PCCS were validated by comparison with transient test data from some separate effect tests and integral tests, and used to evaluate the heat-removed capability of the PCCS under the postulated events, such as a loss-of-coolant accident (LOCA) and a main steam line break (MSLB). The advanced 3rd generation pressurized water reactors of AP1000 project were build in China, and the future advanced PWR with higher power will be researched and designed. So it is very important to develop a new code with self-owned intellectual property rights, which is used for the simulation and analysis of the PCCS performance. In this paper, the main ideas of the code design, including the framework of the code, the important mechanism models and the code validation, etc., will be introduced. In addition, the computational fluid Dynamics (CFD) codes also had been applied to solve some thermal-hydraulic problems in Nuclear Reactor Safety (NRS) analysis.