Next in Talking Points series showcases USC takedown of non-light-water reactor delusions

By Linda Pentz Gunter

In the second in the Beyond Nuclear Talking Points series, we bring you Dr. Edwin Lyman’s definitive examination of so-called advanced reactors, or non-light-water reactors (NLWRs).

In a groundbreaking report, Lyman who is Director of Nuclear Power Safety at the Union of Concerned Scientists, debunks almost all of the industry claims for NLWRs, predominantly on the grounds of safety and security risks, but also touching on costs, time, regulations and waste.

The report — “Advanced” Isn’t Always Better. Assessing the Safety, Security, and Environmental Impacts of Non-Light-Water Nuclear Reactors — can be found in full here on the UCS website. We appreciated the opportunity to condense it into our second Talking Points, all of which are free to download, print and distribute widely.

As Lyman writes in the executive summary of the report, nuclear power in general is replete with flaws: “. . . the technology has fundamental safety and security disadvantages compared with other low-carbon sources. Nuclear reactors and their associated facilities for fuel production and waste handling are vulnerable to catastrophic accidents and sabotage, and they can be misused to produce materials for nuclear weapons.”

The study’s conclusion is that pursuing “advanced” nuclear reactors is too slow, too resource-intensive and too dangerous and won’t result in improvements over light-water reactors.

The report, and our Talking Points, lay out a number of the key arguments.

The current designs, still on paper, all present considerable safety risks. Sodium-cooled reactors could explode like a small nuclear bomb under severe accident conditions. High-temperature gas-cooled reactors use fuel that, contrary to claims, is not “meltdown proof”. Molten-salt-fueled reactors are also not meltdown-proof and, under some circumstances, the hot liquid fuel they use could heat up and destroy the reactor in minutes.

The costs of these “advanced” reactors are too high to justify their flimsy promises of improvement over traditional light-water reactors, especially given that the time needed urgently to address climate change is extremely short. Building the expensive new facilities and infrastructure NLWRs would need to manufacture, manage and eventually store their different kinds of fuels consumes resources better used elsewhere.

As with any new nuclear construction projects, the time and quantity needed to bring these to fruition in order to have any meaningful impact on carbon emissions reductions is unrealistic. At least 25,000 MWe of NLWR capacity would have to come on line globally each year between now and 2050 to reach such goals — five times the recent global rate of LWR construction — a target in which there is no basis to have any confidence whatsoever.

Given the risks and uncertainties of the NLWR designs, a strong regulator is essential. The US Nuclear Regulatory Commission is a weak one. Where extra levels of safety would be needed for NLWRs, for which there is little or no operating experience, the NRC is instead showing signs of leaning toward licensing designs chosen by the U.S. Department of Energy without requiring prototype testing first, running the risk of unanticipated reliability problems and serious accidents.

“Nuclear reactors are vulnerable to catastrophic accidents and sabotage, and they can be misused to produce materials for nuclear weapons”

Promoters of NLWRs have made claims that these could “consume” or “burn” nuclear waste. Lyman’s paper calls this “misleading.” Such reactors, he writes, can only use a fraction of irradiated fuel as new fuel, and separating that fraction — through the necessary prior process of reprocessing — increases proliferation and terrorism risks.

Indeed, it is this necessity for reprocessing that is central to a major downside of NLWRs. Fast reactors such as the sodium-fueled reactor, typically require plutonium or highly enriched uranium-based fuels that are readily nuclear weapon-usable and therefore entail unacceptable proliferation and terrorism risks. 

High-temperature gas-cooled reactors, using high-assay low enriched uranium fuel, are more proliferation-prone than light-water reactors due, in part, to the additional monitoring challenges presented by their fuel fabrication system. 

Some molten salt reactor designs require on-site, continuously operating fuel reprocessing plants — pathways for diverting or stealing nuclear weapons-usable material. 

The position of UCS, unlike that of Beyond Nuclear, is not openly to oppose nuclear power in principal but to ensure its safety. This is a tall order. Lyman concludes his report by saying: “. . . the bulk of nuclear energy-related research and development funding, both public and private, should be focused on improving the overall safety, security, efficiency, and cost-effectiveness of LWRs and the once-through fuel cycle.”

While we support efforts to guarantee better public safety protections for the public from the current fleet of light-water reactors, the position of Beyond Nuclear is that no further development of LWRs should happen, but rather that the country must expeditiously move to a 100% nuclear power phaseout. 

Nevertheless, the specter of “advanced” reactors continues to loom, and many governments remain intent on squandering precious resources on attempts to develop these under the misleading guise of climate mitigation. Therefore, we believe that this comprehensive takedown of the futility of such endeavors is a valuable addition to our Talking Points series.

The full UCS report can be read here. And watch for new installments in our Talking Points series in the coming weeks.

Linda Pentz Gunter is the international specialist at Beyond Nuclear and writes for and edits Beyond Nuclear International.