Small Modular Reactor Technology

Ashley Seni
March 14, 2011

Submitted as coursework for Physics 241, Stanford University, Winter 2011

The United States' transition to clean energy has been marked by many challenges, particularly the disparity between the country's baseload electricity and manufacturing energy needs and the technologies that are available to meet those needs. Nuclear power offers a potential solution to this problem as a low-emission, scalable source of electricity. In an op-ed published by the Wall Street Journal, U.S. Secretary of Energy, Steven Chu, argues that small modular reactor (SMR) technology is the future of nuclear power and offers an economical and scalable option for producing clean energy. SMRs benefit from their small size, ranging from 1/20th to 1/4th the size of large nuclear reactors, and compact design that allows for efficient production in factories and domestic shipping. [1] Chu claims that "would significantly expand the options for nuclear power and its applications." [1]

Developments in SMR technology

As companies work toward the commercialization of SMRs, research and development efforts are focused on the design of light water SMRs. Light water SMRs are flexible for utilities as the modular design allows for capacity to be added incrementally as needed. While large nuclear power plants provide baseload power, smaller modules may be more suitable for small electric grids. [2] Further advancements in reactor design can potentially lead to new capabilities, including SMRs that can supply heat and electricity directly to industrial users or convert nuclear waste into electricity. [2]

GE Hitachi Generation IV PRISM reactor

GE-Hitachi has been developing the Power Reactor Innovative Small Module (PRISM), a compact modular pool-type reactor with passive cooling for heat removal based on the light water reactor design. The reactor has a modular design with two reactor modules that have an electrical output of 311 MWe each. [3] The design utilizes a sodium coolant and operates at 930°F. [3] The metal fuel is obtained from used light water reactor fuel, then reprocessed to otain fresh fuel that has minor actinides with the plutonium. [3]


Energy security and the reduction of carbon pollution are two major national priorities that can be addressed by the development of SMR technologies. Despite the benefits and potential of SMRs, they are no more controversial than conventional reactors, as little is known about their safety level and their level of nuclear waste production. There is clearly a need for funding to develop safe designs that optimize the available resources and electricity production while minimizing nuclear waste and greenhouse gas emissions. The technology's flexibility and scalability is an attractive option for facilitating the U.S.' transition to clean energy.

© Ashley Seni. The author grants permission to copy, distribute and display this work in unaltered form, with attribution to the author, for noncommercial purposes only. All other rights, including commercial rights, are reserved to the author.


[1] S. Chu, "America's New Nuclear Option," Wall Street Journal, 23 Mar 2010.

[2] D.T. Ingersoll, "Deliberately Small Reactors and the Second Nuclear Era," Prog. Nucl. Energy 51, 589 (2009).

[3] A. MacFarlane, "Nuclear Power - A Panacea for Future Energy Needs?," Environment 52, No. 2, 34 (2010).