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The Grid

Small Reactors, Mighty Potential

Advanced nuclear reactors could be a powerful new tool in achieving a clean-energy future.

​Every minute of every day, U.S. nuclear power plants generate about 20 percent of the nation’s electricity, reliably and without carbon emissions.  Nuclear is, by far, the largest, most reliable source of emission-free energy in the country

That’s today.  But what about tomorrow and in the decades ahead?  What does the long-term future of nuclear power look like?  

It might very well be smaller, modular and underground.  

Small Modular Reactors (SMRs) have been around for decades in the form of nuclear powered submarines and other small-scale applications.  But the wide commercialization of SMRs have faced technical and regulatory challenges for years.  

But things are looking up.  In March, the U.S. Senate passed a bill that could accelerate the development of advanced nuclear reactors (including SMRs), providing a boost to technologies that promise to make advanced reactors cheaper, safer, and easier to build.  In June, the Department of Energy awarded $64 million for next generation nuclear projects and R&D. And in September, a bipartisan group of U.S. senators introduced the Nuclear Energy Leadership Act (NELA), a bill that includes a proposal to fund research, development and deployment of advanced nuclear technologies and jobs to support them.

So, the development of new nuclear technologies has some new momentum.  

What are SMRs exactly? 
The term “modular” refers to the ability to construct major reactor components in a factory setting and ship them to the point of use. Additional modules also can be added incrementally as demand for energy increases. To be considered “small,” the output must be less than 300 MWe.  

There are several SMR designs being developed in the U.S., representing a variety of sizes, technology options, and deployment scenarios. These reactors could produce just a couple megawatts up to hundreds of megawatts. Most SMRs would be built below grade for safety and security enhancements, addressing vulnerabilities to both sabotage and natural disaster scenarios.



SMRs take the benefits of nuclear energy and diversify its application, bringing it to new customers for more targeted purposes.  For example, SMRs could bring dependable, carbon-free power to sparsely-populated areas or regions unattached to a grid. They could serve industrial sites like a desalination plant or other large facilities that need a constant supply of clean power. There is even the potential for SMRs to work side-by-side with renewable resources to provide zero-carbon backup energy when the wind isn’t blowing or the sun isn’t shining.    

Best of all, SMRs could potentially overcome some of the obstacles that have inhibited the development of new large-scale nuclear plants, such as lower initial capital investment, shorter construction timelines, and more cost-effective safety controls.  

Exelon: Active on Multiple Fronts
Exelon sees promise for advanced nuclear technologies and is active on multiple fronts to help influence future SMR designs and shape public policy.   

The company, along with Bechtel and MIT, is supporting GE Hitachi on a potentially game-changing SMR design called GEH BWRX-300.  Exelon Generation will be providing its world-renowned operational expertise to help the team simplify the reactor design and reduce construction and maintenance costs. In July, the project was selected to receive funding by the U.S. Department of Energy. Negotiation of the award is underway.

Members of Exelon Generation’s leadership team also sit on the advisory boards of Holtec and NuScale. Each is developing a light water SMR.  Exelon’s leadership within key industry groups, like the Nuclear Energy Institute (NEI) and the Electric Power Research Institute (EPRI), supports their efforts to tackle both the policy and technology imperatives for SMR commercialization. 
 
Challenges 
Even as technology hurdles are crossed, a question remains: Can SMRs compete in the energy market? Next-generation nuclear faces many of the same challenges as existing or new large-scale nuclear plants. However, funding for research and development, and growing support from our elected leaders are helping provide a feasible path forward for this important, carbon-free technology. As the world’s largest source of zero-emission electricity, nuclear energy is necessary to achieve a clean-energy future.