With the dawn of the nuclear age, there was an effort to explore nuclear power in a wide variety of applications, including nuclear-powered ships, locomotives, spacecraft, and even nuclear-powered airplanes, in addition to reactors to produce electricity. The push for peaceful uses of the atom gained steam after President Dwight Eisenhower’s Atoms for Peace speech in December 1953. As James Mahaffey discusses in his book, Atomic Adventures, nuclear-powered jet engines were tested at the Georgia Nuclear Aircraft Laboratory in the Dawson Forest U.S. government complex in Dawson County, Georgia.
Although the technology was demonstrated, nuclear-powered jet engines proved impractical because of their weight and the problems in shielding radiation from the occupants of the plane. However, that is not the end of the story. In recent years, there has been a push for smaller reactors to produce electricity with the goal of being more economical and better able to fit into an electric utility’s grid system. This push has led to the development of so-called very Small Modular Reactors (vSMRs), also known as microreactors, with an output of 1-10 MWe. Features of these reactors include their mobility and the fact they can be transported to where they are needed, including remote sites used by the military. Importantly, these reactors can be built in a factory, unlike larger reactors which must be built on site. With climate change, the need for these reactors could be considered greater than ever, as nuclear power does not emit greenhouse gases or other airborne pollutants.
A key developer of microreactors is HolosGen which employs “HOLOS,” a technology based on a closed-loop turbo jet engine (www.holosgen/technology). In simple terms, the HolosGen reactor is a nuclear-powered turbo-jet engine which sits on the ground and uses the turbine power to convert the core thermal energy to generate electricity. Because they are not airborne, these reactors are not subject to the same weight and shielding considerations as would be the case for a plane; in fact, additional shielding can be and is employed. Conventional jet engines are quite compact and produce impressive power given the thrust they need to provide to get and keep a plane airborne. HolosGen powers its turbo-jet driven generators not with conventional jet fuel, but with safe, melt-tolerant and proliferation-resistant nuclear fuel that remains at safe temperatures even under total loss of coolant.
The HOLOS reactor design has attracted a lot of attention. In 2018 it received a $2.3 million grant from the Department of Energy’s ARPA-E MEITNER program for approximately two years to demonstrate design feasibility and safe operation. In 2016, the Defense Science Board cited HOLOS as a potential solution to provide electricity to remote military installations. The HOLOS design has received the highest marks in peer review panels which evaluate advanced nuclear reactor concepts and has been featured in a series of publications summarizing high-resolution analyses conducted by the Argonne National Laboratory.
Paradigm Shift for Nuclear Power
HolosGen is a revolutionary concept for nuclear-generated electricity. It makes use of much of the current manufacturing infrastructure, employing airplane and other mass-produced parts. Thus, not only is the finished product transportable, but it can be built in a factory using many standard parts. Recently, the Oak Ridge National Laboratory announced that it planned to build key components of a microreactor using a 3-D printer in its Manufacturing Demonstration Facility.
While HOLOS and similar microreactors are not exactly plug and play and you may never be able to order one from Amazon or Carvana, the installation and purchasing process would be much closer to this paradigm than that for Georgia Power’s Vogtle large-capacity reactors, which are being built on site and which have experienced billions of dollars in cost overruns. Even more severe construction problems befell Scana’s Summer reactors in South Carolina, where the cost overruns were so great that the project had to be abandoned after an expenditure of $4 billion.
Looking to the future, there are a variety of applications for microreactors. They can be configured in different sizes with multiple units linked together to provide power to produce differing levels of output distributed through microgrids. For example, the HOLOS Quad, formed by four transportable power modules comprised within a single shipping container, can produce 10-13 MWe and run for 8-12 years without refueling. It can be scaled up further, with a HOLOS Titan composed of four larger modules shipped in four independent shipping containers, coupled at the deployment site to form a power station producing 61-81 MWe – enough electricity to power 66,000 homes. The HOLOS design includes protective features to eliminate or mitigate the consequences of terroristic attacks, sabotage or accident during transport, and segregates the fuel in sealed cartridges.
Microreactors can be configured to maximize power production from renewable technologies to produce diversified, carbon-free energy. In this regard, they can be employed in conjunction with windmills and solar installations to produce electricity in a dedicated “energy farm.” They can also be used as charging stations for electric vehicles and to power seagoing vessels, thereby assisting in reducing pollution and carbon emissions associated with transportation.
The fact that microreactors are transportable means that they can be used for power in remote locations and then removed when no longer needed. This feature has a great appeal to the military, which must often power remote outposts where the transport of fuel is extremely expensive. Also, the transportability of microreactors makes decommissioning more straightforward as the entire reactor, along with the contained fuel, can be moved to a disposal site.
Because of their mobility, microreactors can also provide a key source of emergency back-up power. When the electrical grid of Puerto Rico was devasted by Hurricane Maria in 2017, U.S. Secretary of Energy Rick Perry remembered the past work that was done on transportable nuclear reactors and noted how such reactors could be of great benefit in addressing Puerto Rico’s electricity problems. A transportable reactor would have proved invaluable during the Fukushima Daiichi accident which was caused when a tsunami flooded the emergency diesel generators that supplied back-up power to the reactors and cooling systems. Without this backup power, the reactors could not be cooled, causing their fuel to melt, destroying the reactors.
“Wouldn’t it make abundant good sense if we had small modular reactors that you literally put in the back of a C-17 aircraft, transport to an area like Puerto Rico, push it out the back end, crank it up, plug it in that could serve tens of thousands if not hundreds of thousands of people very quickly. That’s the type of innovation that going on in our national labs.” – DOE Secretary Rick Perry
Work that was undertaken in Dawson Forest approximately sixty years ago may have significant applications to meeting future energy and environmental challenges. New materials and techniques, including 3D printers, make the construction and implementation of micro-reactors more feasible today. A successful introduction of microreactors as proposed by HolosGen may enable the United States to retake the lead in nuclear reactor development. It may also go a long way to fulfilling Eisenhower’s hope of bringing nuclear-generated electricity to the “power-starved regions of the world.”