Slow deployment, safety hazards make SMRs a poor climate solution

Editor’s note: The first part of this feature (“SMRs riddled with high costs, among other ‘unresolved problems”) was published by the NB Media Co-op on July 31, 2022. This article previously appeared on the website of Peace Magazine on July 1, 2022.

Timelines

The other promise made by SMR developers is how fast they can be deployed. GE-Hitachi, for example, claims that an SMR could be “complete as early as 2028” at the Darlington site. ARC-100 described an operational date of 2029 as an “aggressive but achievable target”.

Again, the historical record suggests otherwise. Consider NuScale. In 2008, the company projected that “a NuScale plant could be producing electricity by 2015-16.” As of 2022, the company projects 2029-30 as the date for start of generation. Russia’s KLT-40S, a reactor deployed on a barge, offers another example. When construction started in 2007, the reactor was projected to start operations in October 2010. It was actually commissioned a whole decade later, in May 2020.

The SMR designs being considered in Canada are even further off. In December 2021, Ontario Power Generation chose the BWRX-300 for the Darlington site. That design is based on GE-Hitachi’s Economical Simplified Boiling Water Reactor (ESBWR) design, which was submitted for licensing to the U.S. Nuclear Regulatory Commission in 2005. That ESBWR design was changed nine times; the NRC finally approved revision 10 from 2014. If the Canadian Nuclear Safety Commission does its due diligence, it might be 2030 or later before the BWRX-300 is even licensed for construction. That assumes that the BWRX-300 design remains unchanged. And, then, of course, there will be the inevitable delays (and cost escalations) during construction.

The concern about these long timelines is that the Intergovernmental Panel on Climate Change and other international bodies have warned that to stop irreversible damage from climate change, emissions have to be reduced drastically by 2030. Nuclear power from the BWRX-300 or any of the other SMRs will not even begin to contribute within that time frame.

Waste, Proliferation and Safety

Small reactors also cause all of the usual problems: the risk of severe accidents, the production of radioactive waste, and the potential for nuclear weapons proliferation.

By their very nature, reactors have fundamental properties that render them hazardous. As a result, all nuclear plants, including SMRs, can undergo accidents that could result in widespread radioactive contamination. This possibility was on full display in 2011 when three reactors at Japan’s Fukushima Daiichi nuclear plant melted down. The smallest of these, Fukushima Daiichi-1, had an output of 460 megawatts, only slightly larger than the maximum output of 300 megawatts that characterizes a SMR.

All else being equal, making reactors smaller reduces the risk and impact of accidents. Smaller reactors have a lower inventory of radioactive material and less energy available for release during an accident. But even a very small reactor (say, one that generates under 10 megawatts of electricity) can undergo accidents that result in significant radiation doses to members of the public.

Further, small modular reactor proposals often envision building multiple reactors at a site. The aim is to lower costs by taking advantage of common infrastructure elements. The configuration offered by NuScale, for example, has twelve reactor modules at each site, although it also offers four- and six-unit versions. With multiple reactors, the combined radioactive inventories might be comparable to that of a large reactor. Multiple reactors at a site increase the risk that an accident at one unit might either induce accidents at other reactors or make it harder to take preventive actions at others. This is especially the case if the underlying reason for the accident is a common one that affects all of the reactors, such as an earthquake. In the case of the accidents at Japan’s Fukushima Daiichi plant, explosions at one reactor damaged the spent fuel pool in a co-located reactor. Radiation leaks from one unit made it difficult for emergency workers to approach the other units.

The other undesirable result of any SMR being constructed is increased production of radioactive waste. The physical process underlying the operation of an SMR, i.e., nuclear fission, will always result in radioactive substances being produced. Thus, radioactive waste generation is inextricably linked to the production of nuclear energy, no matter what kind of reactor is used. Despite decades of well-funded research, there is no demonstrated way of safely managing these wastes because of a combination of social and technical problems.

Claims by SMR proponents about not producing waste are not credible, especially if waste is understood not as one kind of material but a number of different streams. A recent paper in the Proceedings of the National Academy of Sciences examined three specific SMR designs and calculates that “relative to a gigawatt-scale PWR” these three will produce up to 5.5 times more spent fuel, 30 times more long-lived low and intermediate level waste, and 35 times more short-lived low and intermediate level waste. In other words, in comparison with large light water reactors, SMRs produce more, not less, waste per unit of electricity generated. As Paul Dorfman from the University of Sussex commented, “compared with existing conventional reactors, SMRs would increase the volume and complexity of the nuclear waste problem”.

Further, some of the SMR designs involve the use of materials that are corrosive and/or pyrophoric. Dealing with these forms is more complicated. For example, the ARC-100 design will use sodium that cannot be disposed of in geological repositories without extensive processing. Such processing has never been carried out at scale. The difference in chemical properties mean that the methods developed for dealing with waste from CANDU reactors will not work as such for these wastes.

Many SMR designs also make the problem of proliferation worse. Unlike the CANDU reactor design that uses natural uranium, many SMR designs use fuel forms that require either enriched uranium or plutonium. Either plutonium or uranium that is highly enriched in the uranium-235 isotope can be used to make nuclear weapons. Because uranium enrichment facilities can be reconfigured to alter enrichment levels, it is possible for a uranium enrichment facility designed to produce fuel for a reactor to be reconfigured to produce fuel for a bomb. All else being equal, nuclear reactor designs that require fuel with higher levels of uranium enrichment pose a greater proliferation risk—this is the reason for the international effort to convert highly enriched uranium fueled research reactors to low enriched uranium fuel or shutting them down.

Plutonium is created in all nuclear power plants that use uranium fuel, but it is produced alongside intensely radioactive fission products. Practically any mixture of plutonium isotopes could be used for making weapons. Using the plutonium either to fabricate nuclear fuel or to make nuclear weapons, require the “reprocessing” of the spent fuel. Canada has not reprocessed its power reactor spent fuel, but some SMR designs, such as the Moltex design, propose to “recycle” CANDU spent fuel. Last year, nine US nonproliferation experts wrote to Prime Minister Justin Trudeau expressing serious concerns “about the technology Moltex proposes to use.”

The proliferation problem is made worse by SMRs in many ways. First, many designs require the use of fuel with higher levels of uranium-235 or plutonium. Second, many SMR designs will produce greater quantities of plutonium per unit of electricity relative to current reactors. Third, in the highly unlikely event that the global market for SMRs is as large as proponents claim, then countries that do not currently possess nuclear technology will acquire some of the technical means to make nuclear weapons.

Conclusion

The saga of Theranos should remind us to be skeptical of unfounded promises. Such promises are the fuel that drive the current interest in small modular nuclear reactors. But, as explained, there are good reasons to expect that small modular reactors will not solve the challenges confronting nuclear power. In particular, they are not economical and thus will fail commercially. Other claims are also often unfounded.

A good example of such flawed claims, with some parallels to Theranos, was Transatomic Power: a company that claimed to have a reactor design that would “consume about one ton of nuclear waste a year, leaving just four kilograms behind”. The company raised at least $4.5 million from investors, including Peter Thiel’s Founders Fund. Subsequently, after Kord Smith, a professor at MIT, reviewed the design and discovered serious flaws, the proponents backtracked on these promises. The causes, according to Smith, were the fact that the original claims did not undergo “any kind of peer review” and also “not listening carefully enough when people were questioning the conclusions they were coming to”.

Rather than seeing the writing on the wall, unfortunately, government agencies are wasting money on funding small modular reactor proposals. Worse, they seek to justify such funding by repeating the tall claims made by promoters of these technologies. It would be better for them to focus on proven low-carbon sources of energy such as wind and solar, and technologies that enable these to provide a much larger fraction of our energy needs.

The path to a world that is secure and ecologically sustainable leads away from nuclear power and small modular reactors.

M. V. Ramana is the Simons Chair in Disarmament, Global and Human Security at the School of Public Policy and Global Affairs, University of British Columbia and the author of The Power of Promise: Examining Nuclear Energy in India.