Multi-Application Small Light Water Reactor (MASLWR). Annex I

The Multi-Application Small Light Water Reactor (MASLWR) design was developed through a collaborative effort sponsored by the nuclear energy research initiative (NERI) programme of the U.S. Department of Energy (DOE). The design and testing team was comprised of staff from the Idaho National Engineering and Environmental Laboratory (INEEL), Oregon State University (OSU), and NEXANT-Bechtel. The primary objectives of the project were to develop the conceptual design for a safe and economic small, natural circulation light water reactor, to address the economic and safety attributes of the concept, and to demonstrate its technical feasibility by conducting testing in a scaled integral test facility. The design has evolved from an initial concept that employed a primary system layout similar to a traditional pressurized water reactor (PWR), with U-tube steam generators external to the reactor vessel, with the thermal centers of the steam generators elevated to enhance natural circulation. The preliminary estimates for the early design indicated that the busbar cost would be about 5.7 cents/kWh, which is far above the goal of 4 cents/kWh. It was concluded that cost reductions could be achieved by using smaller, simpler, factory-assembled units. Therefore, the focus of the project was redirected to a self-contained modular reactor design consisting of an integrated reactor vessel, steam generator, and high-pressure containment vessel. The entire reactor module would be shop fabricated and transportable to a site on most railways or roads. This sealed modular design eliminates the need for on-site refuelling. The MASLWR concept relies on available nuclear technologies. The nuclear core and turbine generators designs were based on configurations used in a typical PWR. This allows the use of current industry expertise and manufacturing capabilities. The novelty of the system comes from the integration of the entire primary side into a single modular unit with an independent steel containment, and in the completely passive safety systems. The technical feasibility of the MASLWR concept has been confirmed by the integral system tests conducted at Oregon State University (OSU)