Thinking Small, Nuclear Power Enters Distributed Era

The nuclear power industry’s drive to deploy small, modular reactors (SMRs) took a significant step forward this month.  Nuclear technology vendor Babcock & Wilcox formalized its funding agreement with the U.S. Department of Energy (DOE) for the mPower reactor project.  With $79 million of federal funds for this year (and a total of $150 million over the five-year program), B&W plans to build a prototype SMR at the Clinch River site in Tennessee, owned by the Tennessee Valley Authority.

SMRs have gleamed in the eyes of nuclear power providers for a decade now, as the industry seeks a new model for economical, carbon-free power generation for the 21^st century.  The Fukushima nuclear accident, in March 2011, seemed to squelch the so-called “nuclear renaissance,” but many countries – including the U.S., South Korea, Russia, China, and even Japan – are moving ahead with plans for small reactors that can be factory-crafted (thus “modular”) and assembled on-site.  Economies of scale have dominated the nuclear power industry for most of its life, with a reactors expanding to 1000 megawatts (MW) or even 1,500 MW.

Now, many believe that the future of nuclear lies in SMRs, of under 300 MW, that can be arrayed in multiple configurations, giving power generators more flexibility and, in theory, lower capital costs.

There are more than a dozen designs currently under development for SMRs.  Most of them are simply miniaturized versions of existing, light-water reactors; the mPower is a 180-MW “advanced integral pressurized water reactor” that could be deployed not only for supplying power to the grid but in more specialized applications, such as powering remote oilfield operations or desalinating water.

Arctic Nukes

“SMRs offer TVA an important new option for achieving clean, base-load electricity generation and we are ready to begin the work to understand the value of that option,” said TVA senior vice president of policy and oversight, Joe Hoagland, in a statement.

Increased safety is also a feature of SMRs, at least potentially; NuScale Power, a startup principally backed by Fluor Corporation, said at an SMR conference earlier this month that it has developed an inherently safe system that, in case of a full power shutdown such as happened after the Japanese earthquake and tsunami, will self-cool the reactor without the need for external power or water.  Essentially, the NuScale design uses a simplified set of water valves that flip open automatically in case of a power disruption.

“Because of the simplicity of the NuScale design, only a handful of safety valves need to be opened in the event of an accident to ensure actuation of the [emergency cooling system],” said Jose Reyes, the co-founder and CTO of NuScale, speaking at the Nuclear Energy Insider SMR Conference in Columbia, S.C.  “These safety valves have been mechanically pre-set to align to their safe condition without the use of batteries following a loss of all station power.”

The earliest applications for SMRs are likely to be distributed generation in remote places, including military forward operating bases.  A Russian consortium is constructing a barge-mounted SMR, based on the nuclear engines that power icebreaker ships, that can be deployed in some of the least hospitable places on Earth.  The idea of nuclear reactors powering oil and gas production in the Arctic is hardly a reassuring thought for environmentalists and diplomats.  But it’s likely to become a reality in less than a decade.

The mPower prototype is scheduled to be up and running by 2022.