Design of Reverse Flow Blockage Device for Reactor Coolant Pumps

摘要

Future Sodium cooled Fast Reactors (SFR) in India, are being designed with 3 Reactor Coolant Pumps (RCP). Reactor Coolant Pumps (RCP) are used in pumping the coolant fluid through the reactor core. As the RCPs are operating in parallel, failure of one pump will result in a significant portion of the pumped coolant to bypass the core via tripped RCP. Thus, the reactor has to be shut down and the tripped RCP has to be replaced, which results in down time. Operation of reactor with only two RCP (2/3 mode) will supplement the power generation. Henceforth, if the flow path through the tripped RCP is made highly resistant as compared to the core, then eventually, flow from the two operating RCPs will go through reactor core. Such a flow blocking/resisting arrangement can also provide the flexibility during reactor startup. A cylindrical shell is designed for closing the suction passage of the pump and the shell is raised or lowered from above the roof slab with the help of tie-rods. The cylindrical shell (sleeve shell) is designed to withstand water hammer shock due to inadvertent sudden closure of the suction passage. To determine the shell thickness, pump performance curves are developed based on reactor operating conditions. The sleeve shell will not be able to perfectly close the suction passage as space is required for movement of sleeve shell over the pump shell, thus a study is performed on incorporating a labyrinth to minimize the leakage.