I thought the extremely compelling rationale for Fusion was (assuming it can be done) not just orders of magnitude more energy, but also extremely little safety risk and on top of that, your "waste" is pure helium. Am I misinformed? This seems like of course we'd be willing to put the effort into that.
No. The cladding of fusion chamber is bombarded with neutrons and has to be replaced frequently, producing radioactive waste. This a drawback of all experimental designs today, AFAIK.
JET could run above break-even in neutronic fuel cycle.
The MSR designs in work today are at a very early stage of development. We cannot and will not know their economics until we have a fleet operating and see what regulations show up as a result of operating history. Just like LWRs experienced in the 1970s. 1965s Oyster Creek was extremely cheap. 1980s reactors, not so much.
Molten Salt Fuel has a number of advantages over solid fuel pellets. I specially like the solution of the SSR where they copy the same assembly type setup and the whole process works very similarly to a PWR or Sodium reactor, but at the same time they retain the inherent advantage of liquid fuel.
> The MSR designs in work today are at a very early stage of development.
They are in advanced talks with the Canadian regulator and are planning deployment this decade.
> We cannot and will not know their economics until we have a fleet operating and see what regulations show up as a result of operating history. Just like LWRs experienced in the 1970s. 1965s Oyster Creek was extremely cheap. 1980s reactors, not so much.
We know now that building the nuclear station and financing of that build is the absolute cost killer for new nuclear, so having designs that are smaller by at least an order of magnitude for the same power output is gone be the huge advantage.
I don't really see how the situation now compares to 1965 where over the next 15 years the regulatory environment changed 100%.
The companies going threw regulatory approval are building to a known set of regulation for the design and the operation of their plants. The are building passively save systems with advanced operations that are designed for much fewer human operation (as any new design reactor design would).
If they get licensed, it is hart to see what possible change in operation could impact the cost to such a huge degree.
Primary loop of a MSR is equivalent to a cladding of a solid fuel assembly. You get a REACTOR at the same cost/MWe of solid fuel assembly. Ni alloys are cheaper than Zr alloy. So, early MSR designers will not opt for maintenance of the primary loop.
Here's link to Weinberg's PIUS-LWR https://www.annualreviews.org/doi/pdf/10.1146/annurev.eg.10....
The nuclear industry abandoned such turnkey contracts, and for good reason. They made a desperate return recently, with even sadder result: the bankruptcy of Westinghouse.
However, while PWR SMR can help you with modular construction and factory mass production, you lose the economics of scale of a larger reactor. I wish NuScale success, but I do not think the technology is very promising to actually reduce cost by the required amount. You need to be competitive with cheap gas prices.
PWR in general are a technological deadend that should never made it past the 70s. Even the inventor of PWR said so in the 60s and that is why he worked on Molten Salt Reactors.
However if you want to know about the future of nuclear, the only place where we see serious development in the Western world, look at Canada. They had a strong program of CANDU reactors and a globally respected regulatory agency. CANDU has now been privatized and the Canadians started to look more into Generation IV reactors (even while I totally dislike this terminology).
This has lead to Canada becoming a hub for nuclear innovation, as the Canadian regulatory system 'only' requires you to prove a safety case that is technology independent. In the US they just say 'show us the secondary pump for the steam', 'my reactor does not have any steam inside of it', 'PLEASE SHOW US THE SECONDARY STEAM PUMP'. facepalm
The company that is most advanced in the regulatory process is Terrestrial Energy (www.terrestrialenergy.com) and another one that is a couple years behind is Moltex Enery (www.moltexenergy.com) an originally British company who moved to Canada because the British regulatory agency is possibly even more disfunctional then the US one.
Both of these reactors are based on the Molten Salt reactors and really nice designs. The are both Fast Burners in their first iteration, while Moltex initially focuses more using Canadian CANDU Waste as fuel, Terrestrial Energy has opted to take the most commercially available fuel, 5% enriched Uranium.
However, both hope to eventually develop a Molten Salt Thorium Breeder design, long consider the holy grail among nuclear fans.
Terrestrial Energy is already working on a project to deploy their first US reactor in Idaho. The hope is that the US Regulatory Agency (who have realized how nonsensical their regulation are) are ready with a improved framework and that much of the work done for Canada will be accepted in the US.
The Moltex Ractor is special because it combines Molten Salt with a more traditional fuel assembly design (reusing well tested materials from Sodium Reactors). Listen here if you are interested: https://www.youtube.com/watch?v=TvXcoSdXYlk
Terrestrial Energy is building a more traditional Molten Salt reactor but instead of switching out fuel assemblies, they just replace the whole core. See here for more on their design: https://www.youtube.com/watch?v=OgTgV3Kq49U
For a more economic focus analysis on their design: https://www.youtube.com/watch?v=zsAfUBzRp3M
One thing that is often missed with this discussion is how irrelevant fusion really is in some ways. Fission has an energy density of 10^12 over chemical, Fusion is much better at 10^15, but really if we are not willing to switch to Fission, a technology we already have, why would be do it for Fusion.