I wish I knew why some nuclear advocates feel that it’s worth their time to spread as much negative information as they can find about the potential utility and value of advanced nuclear power technologies.
IMO, modern water cooled reactors qualify as advanced in the same way as a modern BMW engine qualifies as advanced even if it is still using the same Otto Cycle (4-stroke spark plug internal combustion) that was first patented in 1861.
There are very innovative water-cooled reactor designs. Reactors that don’t use any coolant pumps or nuclear power plants that can be assembled almost as easily as Lego sculptures offer new, valuable capabilities.
I like large, water-cooled reactors when they can fit customer needs as long as they can be properly managed and completed. (Large grids do not necessarily have room for large reactors because they likely have sufficient generators to supply their current loads.)
Even though experiments have been conducted with other coolants over the years, there were a number of reasons, some having to do with the state of material science or controls technology at the time, those systems were not deployed commercially. (Does anyone remember the “success” of the Lisa or the Next? Did those experiences mean that the Macintosh wasn’t advanced and shouldn’t be developed? Did the failure of the Newton prevent the development of the iPad?)
It’s not often talked about, but the adoption of water cooled reactors had a purposeful geopolitical aspect. The US built excess enrichment capacity for a large scale weapons buildout during the Truman and Eisenhower administrations.
When we finally chose to allow selected private companies to participate in developing power reactors, we had strong political and economic motives to ensure that our standard became the world’s standard. We thus offered low enriched uranium at prices below cost to better compete against natural uranium reactors. US vendors also built large order books by over promising and under delivering on price and schedule. By the time the customers realized they were paying more and getting less, it was too late for customers to change their technology selection.
The fact that alternative nuclear concepts were not deployed and water cooled reactors (both heavy and light) WERE deployed does not mean that the water cooled reactors have inherent superiority.
The fact that we have built and operated a substantial number of water cooled reactors gives that technology a leg up. But it’s incorrect to say that we know how to build them well or affordably. Our parents might have done a reasonably good job, but their skills are not inheritable. There are some teams that have done pretty well, but they are mostly inaccessible to us.
Smaller reactors offer the opportunity for smaller capital expenditures, less complex financial arrangements, smaller partnerships and less overall risk. They also offer the opportunity for significantly shorter construction periods and faster learning.
By definition, we need to build more units of smaller reactors to produce the same amount of power as fewer units of large reactors, but building more units enables us to move further down a Wright’s Law learning curve.
Some design alternatives address some of the characteristics of water cooled reactors that are inherent to the technology.
Example: Helium and nitrogen are inert gases that do not corrode tanks, pipes and heat exchangers. They do not change phase within the potential operating temperature and pressure conditions of a reactor. They can be heated to very high temperatures. (There is a currently operating helium cooled reactor [Japan’s HTTR] that has been operating with a coolant outlet temperature of 950 ℃ for years using 1990s material technologies. With modern materials, higher temperatures are possible.)
The best reason for higher operating temperatures is the dramatically improved efficiency those temperatures enable. Moving from 30% to 40% is a 33% increase. That doesn’t just affect fuel costs; it means that the same equipment might be able to produce 33% more units of output that can be sold into the market.
Higher temperatures might also allow designers to use Brayton cycle machines or even combined cycle machines borrowed from the highly successful natural gas power plant industry.
Molten salts will contain and isolate radioactive materials if the salt leaks. There is no driving force that would distribute materials outside of the plant boundaries.
Reactors cooled by sodium or lead can enable fertile material to be converted to fissile material at a rate that exceeds the consumption of fissile material. Breeding economics change when uranium prices increase. (The current price of uranium is about 3 times as high as it was a year ago.)
These POTENTIAL advantages of advanced reactors are not a given, but they can be powerful if achieved.
I don’t understand why some advocates think that we have an either-or choice to make. The nuclear sector is a tiny fraction of the size that it needs to be in order to make the kind of contributions it is capable of. Having a wide variety of projects to work on and technologies to refine helps attract some of the best and brightest engineers, technicians, financiers and marketers to the sector.
Start up ventures often attract talent that big, established companies would stifle. Some of that talent comes in the form of mid to late career professionals with refined skills in similar or contributing industries. It would seem nearly impossible for an establishment nuclear company to attract a SpaceEx engineer or the founder of a successful drone company.
Building more of what we already know might offer more immediate returns, but it isn’t necessarily the best recipe for long term success.
I’m a fission fan. I invite others to join me and to stop investing time in bashing new nuclear.
I should also disclose that I’m a venture capitalist with a significant focus on the advanced nuclear sector, so I am professionally biased towards that sector.