“In the field of nuclear power safety, experts have established a million kilowatt level PWR nuclear power unit model based on the MAAP4.0.3 program, studied the serious accident process of heat pipe rupture accident combined with safety injection failure, and explored effective mitigation measures. The research results indicate that the larger the rupture area, the earlier the pressure vessel fails, and the greater the hydrogen production during MCCI process; Early deployment of the safety injection system can effectively alleviate the process of accidents and prevent pressure vessel failure.”