The pool-type reactor, as a low-pressure small modular reactor, has broad application prospects in regional heating and industrial heat supply due to its high inherent safety features and modular design characteristics. To ensure that reactors located near residential areas have adequate safety margins, the design and verification of their passive safety systems are particularly critical. This study, based on a system analysis program, constructs a thermal–hydraulic calculation model for the pool-type reactor, focusing on the system response characteristics under Loss of Flow Accident (LOFA) conditions and the operating mechanisms of Passive residual heat removal systems (PRHRS). The results show that under accident conditions, safety devices such as the passive residual heat removal system and natural circulation cooling system functions as intended under design conditions, fully validating the pool-type reactor's ability to achieve safe shutdown and long-term residual heat removal even after the loss of active cooling. This research provides important theoretical support for the safety design optimization and operational evaluation of pool-type reactors.