The Holtec HI-SMUR 140 light water reactor was presented in 2011. (26 pages) It will be factory mass produced.
Holtec, through its subsidiary, SMR L.L.C., is one of four finalists in the running for a $452 million grant from the U.S. Department of Energy. The plan is for the U.S. to fund two small modular nuclear reactor designs that will become available for licensing and production by 2022. Holtec estimates it can build its new (140 MWe) plant for about $800 million. The company’s more likely future market is probably outside the U.S. The plant will need to sell 1,000 units to make the small nuclear reactors a financial winner.
The new reactor is named HI-SMUR 140, derived from Holtec Inherently Safe Modular Underground Reactor. As the above words in HI-SMUR’s name indicate, its core is located completely underground, it is operated by gravity induced flow (no reactor coolant pump), it does not rely on off-site power for shutdown (Inherently Safe), and it can be installed as a single unit or a cluster at a site (Modular). Passive in every aspect of its operation, HI-SMUR’s principal technical mission is “safety and security first.” HI-SMUR’s principal safety credentials derive from locating the core underground in a reactor vessel that has no penetrations to provide a drain-down path for the reactor coolant. Eliminating the reactor coolant pump and the need for emergency or off-site power to cool the reactor core in the event of a forced shutdown, are among the distinguishing design features of HI-SMUR that define its mission of utmost safety and security. Other major features of HI-SMUR are its small footprint, minuscule site boundary dose, large inventory of coolant in the reactor vessel and its modularity, i.e., the freedom to build the number of units at a site to best suit the owner’s projected power needs. The expected duration of the construction life cycle is 24 months.