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| Fig. 1: SSTAR Reactor. [5] (Courtesy of the U.S. Department of Energy.) |
While most in the power industry are writing-off the future of nuclear energy, a group of companies are working on bringing to market a new kind of nuclear power plant. Micro nuclear reactors hold a lot of promise because they can easily be modularized and distributed across cities and countries, generating power for years without human intervention. While the power industry today is highly centralized, this decentralized paradigm is not as outlandish as it may seem.
In the late 1800s, when the electricity industry was still nascent, two pioneers, Thomas Edison and Nikola Tesla were locked in an intense competition to define and capture the electricity generation industry of the future. Edison, a strong patron of DC (Direct Current), preferred a model where every home, factory and office building had its own coal or oil fired generator. Tesla, however, saw the potential of AC (Alternating Currents) and envisioned a future in which electricity would be generated in large centralized facilities and transported hundreds of miles to their end users. After a long legal and commercial battle, Tesla was proven victorious. However, 200 years later, many within the power industry are starting to see the benefit of decentralized power generation. A big reason why this trend is playing out is that power-generation technologies have gotten cleaner and less intrusive. When Edison spoke about decentralized power generation, it usually referred to coal-fired generators that caused a lot of noise, emitted noxious fumes and had to be refueled and repaired frequently. Fortunately, today we have better options in the way of solar and wind power, and hopefully in the next couple of decades, nuclear! [1]
While nuclear technology has been well understood since the 1950s, it's extremely challenging to plan and setup nuclear power plants today. This is primarily because they are extremely capital intensive and complicated, and are at a constant risk of human accidents, and worse yet, intentional tampering. Many research centers and companies are trying to build safer and possibly risk-free reactors. One hears the mention of 'traveling-wave-reactors' and thorium based reactors, but these are still very large, complicated and expensive experiments that are struggling to see the light of day. Meanwhile, some companies are taking a slightly different approach: micro nuclear reactors, which are smaller, cheaper and simpler. Why is this better than conventional nuclear power? The fact that they are smaller and cheaper means that they can be manufactured and setup without billions of dollars of up-front capital costs and without the delays that are usually associated with large, complicated nuclear power projects. The companies that are making these reactors are also designing them for zero human interaction or operation. This means that they can be permanently sealed and buried under the ground and run for a several years without human intervention. [2]
Micro-nuclear reactors, if brought to the market at a reasonable price have countless applications. The advent of startups such as Solar City and Sun Run that setup rooftop solar power shows that distributing generation closer to demand center can be more economical than large centralized power plants. This is because they significantly lower transmission costs and losses. In a similar vein, distributed micro-nuclear reactors could be used in large cities, providing power 24 hours a day, which even solar cannot achieve. They can also be used in offices, factories, industrial facilities and data centers to reduce reliance on grid-based power, and to eliminate the need for a back-up diesel generator. The economics of this would work even better in the developing world where most factories and office buildings run expensive diesel generators when they face power-cuts, which are quite frequent in many countries. Finally, micro-reactors could also be used to power large ships, offshore oil rigs and any remote facilities beyond the access of the grid, eventually including space exploration vehicles. [3]
Not so surprisingly, seeing the large economic potential for such reactors, many companies, small and large are betting on them. Toshiba and the Japanese government are working on the Toshiba 4S (Super safe, small and simple) micro sodium reactor. The reactor would be sealed in a vault and buried 30 m underground. The rated capacity of this plant is starting at 10MW but is expected to soon increase to 50 MW. [4] Another similar product is the SSTAR (Small, sealed, transportable, autonomous reactor), a modular plug-and-play, fast-breeder reactor being designed by the US Lawrence Livermore National Laboratory. It is expected to produce a constant capacity of 10 to 100 MW for nearly 30 years. A solid capsule only 15 m high and 3 m wide, the reactor is designed to be tamper resistant and free from human interaction. The first prototype for this promising reactor is expected in 2015 but 3D renderings are already available today, as shown in Fig. 1. [5]
While this new breed of micro nuclear reactors promise to be tamper resistant and safe, the biggest risks remain to be the ones that are not yet known. Most nuclear reactors are designed to be accident and tamper proof but that just means that the engineers designed to avoid any risks or accidents that they could foresee. This does not account for the unforeseeable. Given the fact that these reactors are less guarded and monitored, while at the same time being in closer proximity to civilians, they may actually be riskier and more dangerous than conventional nuclear power plants! However, every power generational technology comes with its share of pros and cons and it's up to individual countries and their leaders to decide their energy mix. While developed countries like the US can do without nuclear based power, many of the world's fastest developing countries like India and China have to choose between nuclear and much more polluting sources of power like oil and coal to maintain their rapidly growing energy base-load, which can never be met by intermittent solar and wind. So in the case of many developing countries nuclear, with all its risks might still be a better option. Or maybe even the only option.
© Anirudh Tikkavarapu. 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] J. Jonnes, Empires of Light: Edison, Tesla, Westinghouse, and the Race to Electrify the World (Random House, 2004)
[2] B. Bradford, "Are Mini-Reactors The Future Of Nuclear Power?" National Public Radio, 4 Feb 13.
[3] "Thinking Small," The Economist, 14 Feb 14.
[4] "Under The Hood With Duncan Williams - Toshiba 4S," Nuclear Street - Nuclear Power Portal, 27 Jan 2010
[5] G. Rennie, "Nuclear Energy to Go: A Self-Contained, Portable Reactor," Lawrence Livermore National Laboratory, Science and Technology Review, July/August 2004, p. 20.
[6] E Adijanto, "Small Scale Nuclear Energy ," March 21, 2012
[7] A. Seni, "Small Modular Reactor Technology ," March 14, 2011
[8] C. Yu, "Small Nuclear Reactors ," March 7, 2011