Abstract: Leakage detection system is one of the most important parts of the steel liner for long-term radioactive storage pool. In order to confirm the key design parameters of the leakage detection system, the analysis work is performed by risk management analysis and hydrodynamics calculation methods. Based on the analytical conclusion, the detail design of the leakage system for the spent fuel storage pool liner of 3rd generation nuclear power plants is cited as an example. Moreover, it shows that, there is sufficient design margin for the spent fuel pool system design by comparing the water replenishment capacity and liquid level alarm design of PTR system with the obtained data.