Small Nuclear Reactors: Background, Potential Applications, and Challenges

Serena Harber
February 19, 2017

Submitted as coursework for PH241, Stanford University, Winter 2017


Fig. 1: This is an illustration of a light water small modular nuclear reactor. [4] (Courtesy of the U.S. Government Accountability Office. Source: Wikimedia Commons)

According to the Princeton Andlinger Center for Energy and the Environment, "a reactor is called 'small' if its capacity is less than 300 megawatts." This is "roughly three times smaller than the 1,000-megawatt reactors" that are commonly seen and referred to. [1] SMR's are also often designed in such a way that they can be assembled in a factory and moved to the designated location to be installed. This is possible because of the more compact size. SMR's are not a new technology or concept, however the plausibility of using SMR's in everyday life and potentially replacing other sources of energy is a fairly recent concept. While research on this topic has been performed for quite a few years now, SMR technology is closer than ever to being integrated into society by governments and larger entities. Furthermore, there is significant argumentation for replacing large nuclear plants with small nuclear plants for financial reasons. This could potentially "postpone the need for 'decommissioning,' which is expensive". [1]

Due to the relatively small and mobile nature of the SMR's, they are of great interest to governments and private groups alike. Large nuclear reactors are fraught with complications such as finding space for installment, financing, and timely construction. SMR's are a viable solution and governments such as Russia and France have already begun construction and utilization of this technology. [2] Furthermore, SMR's are of great interest due to their potential to curb CO2 emissions as an alternative source of power. [1] This report seeks to evaluate the potential benefits and applications for SMR's in the upcoming decade as well as consider the potential downsides of utilizing SMR's moving forward.

Potential Benefits and Applications

SMR's are already being utilized by multiple parties, including "on nuclear submarines and in some developing countries such as India and Pakistan". [2] Some major upsides of SMR's compared to larger nuclear reactors is that they are more transportable, require less uranium fuel (which could potentially lead to fewer meltdowns), and are more affordable at initial market prices. One of the major advantages to SMR technology is the initial economic benefit. While large nuclear reactor sites are extremely costly and difficult to finance, SMR's are more feasible and thus open up the opportunity of harnessing nuclear energy for more parties globally. To illustrate this matter, consider France for a moment. A French energy company, EDF, had plans to build new large reactor sites in France and Finland. However, due to potential safety concerns, "the plans went billions of euros over budget". [2] The problem lies in the fact that large nuclear reactors take more time to build and check safety features. Thus, SMR's could help overcome this barrier of financial and time pressures. Evidently, SMR's have already begun to infiltrate our world in tangible ways. However, SMR's are not as widespread as one might predict considering their many advantages. As governments and private entities begin to adopt SMR's and harness the capability of SMR's to produce "cleaner energy," it is also important to consider the potential downsides and dangers associated with SMR's.


One challenge to small nuclear reactors is the cost effectiveness of utilizing them on a large scale. Although SMR's are cheaper initially due to a lower cost per unit, the most obvious drawback is the increased running costs. [3] Since these reactors are smaller and produce less energy per unit, due to economies of scale, power output decreases while other costs stay constant. [1] This is probably the most substantial reason for why SMR's have not yet emerged in a widespread context.

Other challenges include dealing with the waste products of SMR's, however this is the same for full scale nuclear reactors as well. Additionally, people have mentioned the existence of SMR's could be dangerous for terrorist activity, however I do not foresee this being as significant of a problem as some people have predicted, considering even SMR sites have security and are managed closely. [3]

Moving Forward

Although long-term costs remain a barrier to SMR's becoming a new standard in the energy sector, this may change within the next few years. In terms of cost structures, the Andlinger Center review finds that "If the number of small plants constructed becomes large enough, if 'learning' is strong enough, and if the diseconomies of small scale are weak enough, five 200-megawatt reactors could become cheaper than one 1,000-megawatt plant". [1] This is encouraging speculation to suggest that SMR's do have a bright future for progress in the energy sector. Moreover, there are two highly compelling potential applications for SMR's. The first situation that may be ideal for SMR's is "in groups, where several small reactors are an alternative to one large one". Secondly, SMR's may be applicable when used "individually, in remote, isolated locations where a large reactor is unsuitable". [1]

Considering this is a technology that is constantly being innovated and improved, I believe we will see increased use of SMR's within the next decade. In a similar vein, an article considering US and UK motivations to implement SMR technology predicts, "2025 is a realistic start date for the first small modular reactor in the west, which will be in one of these two countries". [1] Looking forward, SMR's are likely to proliferate in an increasingly energy dependent global climate.

© Serena Harber. 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] "Small Modular Reactors: A Window on Nuclear Energy," Andlinger Center, Princeton University, June 2015.

[2] K. Stacey, "Small Modular Reactors Are Nuclear Energy's Future," Financial Times, 25 July 16.

[3] C. Yu, "Small Nuclear Reactors," Physics 241, Stanford University, Winter 2011.

[4] "Nuclear Reactors: Status and Challenges in Development of New Commercial Concepts," U.S. Government Accountability Office, GAO-15-652, July 2015.