Physics and safety aspects of the minimum attention plant

The Minimum Attention Plant design is based on a self-pressured, indirect-cycle light water reactor with multiple once-through steam generators located within the reactor vessel. Primary coolant flow is initiated and maintained solely by natural circulation. The design of the reactor system provides major operational and safety advantages compared to conventional designs rated at 500 MWe or less, as well as major simplifications and plant equipment reduction, without requiring significant departure from existing LWR technology. Reactor power changes throughout lifetime are accommodated through primary system pressure and temperature changes without requirement for soluble boron or control rod motion. The absence of external coolant loops and large pipe connections to the reactor vessel eliminates or limits major classes of potential accidents, including loss of flow, loss of coolant, and steam line break