NuScale Power, LLC, announced today it has received US patent #8,437,446 for its Steam Generator Flow By-Pass System which relates to a system for removing decay heat from its reactor.
How it works – Integral reactor designs do not include external piping and flow paths that may be used in traditional PWR reactor systems for controlling or directing flow of coolant through the core under off-normal conditions. In particular, during scenarios which result in partially filled systems, current Pressurized Water Reactors (PWR) designs must prevent buildup and precipitation of boron crystals at the outlet of the core region by “back flushing” the system through special alignment of the piping from the steam generator to the reactor coolant pump and back to the reactor pressure vessel (called the “cold leg”) and piping between the reactor pressure vessel and the steam generator (called the “hot leg”). Since NuScale Power Modules incorporate integral systems and they do not have these external large reactor coolant piping systems, other methods of ensuring coolant circulation are needed. The patent granted to NuScale provides a patented method for providing this important coolant circulation in integral systems.
Last month, NuScale announced a major technological breakthrough whereby the NuScale Power Module does not require any operator action, electrical power—alternate current (AC) or direct current (DC)—,nor additional water beyond system inventory, to be able to achieve safe cooldown in a station blackout condition.