Experimental study on transient running characteristics of passive containment cooling system under heave conditions

With the vigorous progress of nuclear industry under marine environment, nuclear safety remains a top priority. Floating nuclear power plants rely more on the passive containment cooling system (PCCS) due to the lack of external energy support. The marine environment will impact the operational efficiency of PCCS. Therefore, this study experimentally investigates the impact of heave motion on transient running characteristics. Parameter analysis is carried out to reveal the influences of various parameters on the transient running characteristics. The experimental results show that the heavy condition promotes faster heat dissipation within the containment simulation vessel. The average pressure drop rate increases as the amplitude of the additional acceleration. The maximum pressure drop rate is essentially unaffected by heavy motion. Meanwhile, the effect of cooling water temperature on the transient characteristics can be ignored. In addition, a non-dimensional empirical correlation for response time is developed to reveal the relationship between the heat transfer capability under heavy condition and stationary condition, while the deviation mostly within ±20 %. Studies on the relevant physical processes or phenomena are valuable for safety analysis or accident study related to PCCS under heavy conditions.