SLIMM-Scalable Liquid Metal Cooled Small Modular Reactor

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Background: Ensuring access to energy is one of the major challenges the world faces today. The United Nations estimates that nearly one billion people have unreliable access to electricity. A continuous supply of electricity is critical in the urbanization of an economy facilitating industrial growth and rising standards of living. One of the ways to secure an electricity supply is through small modular nuclear reactors (SMRs). SMRs offer specific attributes that make them attractive for remote and isolated communities with limited/seasonable access to fossil fuel supply and to countries and island nations with small electric installed capacity and no or limited access to an electric grid. SMRs are an attractive option to electric utilities operating in regions with modest growth in electricity demand and/or modest financial resources. While SMRs could be financially attractive inherently safe and provide for up to 300 MWe of electricity compared to a typical large nuclear plant they present many challenges including the design of a central control room operators’ training for coordinating many units on a single site used fuel handling (storage and processing) and economic competitiveness. Furthermore the majority of SMRs have thermal neutron spectra which are relatively large and have a limited operation cycle length between refueling of 1.5-7 years. There is a present market need for further technologies to be developed to run more efficient small modular reactors. Technology Description: University of New Mexico researcher has developed a scalable liquid metal cooled small modular reactor (SLIMM). This all passive operation reactor except for the control drives is capable of generating 100 MWth continuously for more than 5 years and a little as 10 MWth for > 50 years without refueling. The SLIMM reactor is cooled by circulation of liquid sodium with the aid of in-vessel coiled tubes heat exchanger during nominal operation and also after shutdown. For long operation life the liquid sodium exits the reactor core < 820 K at which corrosion of the core metal structure is negligible while operating at plant efficiency for electricity generation of as high as 40%. In addition the SLIMM reactor plant could provide not only electricity but also high-temperature process heat for industrial uses such as in oil refinery chemical plants generation of hydrogen fuel food processing etc. and low-grade heat for district/space heating and/or seawater desalination. The SLIMM reactor is to be factory fabricated and assembled and shipped by truck rail or barge to the construction site. The total construction time to online generation of electricity is expected to be as little as 12 – 18 months. A cluster of 10-20 SLIMM reactor-plant modules could be incrementally constructed on the same site to meet growth in base-load electricity or for generating superheated steam for oil-shale recovery in the western of the United States particularly in New Mexico Colorado Oklahoma Texas Montana Wyoming and Utah. The footprint area of a single module is quite small. Single or multiple unites could provide uninterrupted supply of electricity process and low grade heat for space heating in military basses in urban and remote sites with no access to an electrical grid or limited access to fossil fuel year around. The SLIMM reactor power modules could generate 3.5 to 40 MWe. In case of a malfunction of the in-vessel heat exchanges a backup system removes the decay heat generated in the SLIMM reactor after shutdown using natural circulation of ambient air. This walk-away same SMR operates below atmospheric thus does not require a reactor pressure vessel but just a containment vessel. The double wall reactor vessel with argon gas gap provide for redundant and safe containment of the SLIMM reactor.


1) 10 – 100 MWth of thermal power generation or 3.5 – 40 MWe of electricity generation per reactor-plant module. 2) Long operation life of > 5 to 50 year without refueling depending on the nominal reactor nominal thermal power. 3) Generated electric power continue 24/7. 4) Provides passive auxiliary electrical power even after a routine or emergency reactor shut down thus eliminating plant vulnerability to a loss of off-site or on-site power. 5) All passive operation except the reactor control drives. 6) Has two independent reactor control and emergency shutdown systems each is capable of safely shutting down the reactor during a routine or emergency shutdown. 7) Enhanced quality assurance and reliability. 8) Factory fabricated and assembled for construction time of 6 – 18 months. 9) The fully sealed reactor units are replaceable at the end of operation life. 10) Eliminated nuclear proliferation concerns. 11) Highly reliable electric and thermal energy supply for urban areas and industrial uses such oil...

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