Study on passive IVR strategy based on steam turbine

In some NPPs with reactor pressure vessel (RPV) arranged at upper elevation, the water overflowing the cavity and/or condensed in the containment cannot flow back to the cavity only relying on the gravity during the IVR process, and so these NPPs cannot realize passive IVR in long term. To solve this problem, a new passive IVR strategy is put forward. In this strategy, the steam produced in the IVR is used to drive a steam turbine, and a pump is driven by the steam turbine to pump the water in the bottom of containment to the cavity again, to establish the cycle of steam and water and to realize the long term IVR. Detailed thermal hydraulic computation is carried out and the feasibility of the system is proved in this paper. (authors)