Boring nuclear companies are exciting
When you look at the space of nuclear companies, there is a huge rift; on one side, there are a lot of new and innovative designs, most of which haven never been proven commercially, some not even on a lab scale and on the other side are and huge light water reactors. But is there a middle ground?
There just might be! It’s “boring” nuclear.
At least from a regulatory perspective, light and heavy water reactors are a rather boring topic. They become even more so, when the mass of their nuclear inventory gets reduced. (Although the regulations are just as stringent!). There are some quite boring designs from a regulatory perspective:
Last Energy
The latest company I have happened to stumble upon in this regard is coincidentally named “Last Energy”. This company, which is a spin-off of the host of the podcast “Titans of Nuclear”[@NuclearTitans].
This company takes a rather extreme approach towards simplicity. They want to build 20MWe pressurized light water reactor running on <5% U235. Simplification is the main philosophy of their implementation. They plan to achieve scalability and rapid deployment by using a repeatable framework and off-the-shelf components, putting Wright’s law to the test for nuclear.
They want to:
reduce overall costs by simplifying plant operation and maintenance
minimize the potential for delays by eliminating custom configurations
accelerate implementation time by creating a cross-trained operational team
The design uses a fairly standard balance of plant design, which consists of a steam generator, piping to transport the steam to the turbine, an air-cooled condenser, a coolant pumps, as well as water conditioning equipment. The company seems to gamble on some kind of regulatory reform, as they want to use the same materials and design to the same codes as conventional, non-nuclear facilities, instead of the currently prescribed ones. It is my guess that the quoted “3000$/kW” of capex are conditional on that assumption holding true. In their promotional video, it does not look like the reactor “building” contains any kind of neutron shielding, refueling equipment or control rods. It’s highly unlikely that this will be their production design, so I’d speculate that they will have to add certain safety features and scale their design vertically, like other companies already did.
GEH BWRX-300
GEH is following the same philosophy, but with a slightly different approach. They have taken their most modern design, the ESBWR, which wasn’t built even once (presumably due to cost issues), scaled it down and eliminated certain components; they used one of their off-the-shelf turbines and sized the reactor appropriately. It is wholly dependent upon on natural circulation and does not have a reactor coolant pump. It can be cooled in station blackout scenarios for at least 7 days with the water held near the reactor.
Another innovation is their use of SteelBricks a new steel-concrete composite, which allows the building of the reactor containment without rebar and up to 50% less concrete per MW of reactor compared to the ESBWR. They are also eyeing to dig a “vertical” tunnel using tunneling machines, instead of excavating the whole site. I do not know if there are any patents or contracts preventing the adoption of these two technologies, otherwise it would seem advisable for nuclear projects to check the feasibility for new builds. GEH estimates that the BWRX-300 can be built for less than a billion dollar.
HOLTEC SMR-160
HOLTEC seems to be a quiet and quite effective company. It is in the decommissioning and spent fuel storage business. It develops a lot of equipment could also be used to build reactor components, like their robotic welding machines, its HI-TRAN transporter for spent fuel caskets or the Green Boiler (a thermal energy storage).
Their own reactor under development is the SMR-160: a pressurized light water reactor focused on safety, simplicity and reliability. The reactor core is located deep underground. It is designed to not rely on on-site or off-site power to shut down the reactor and get rid of the decay heat to the environment. There are no active components needed to run the reactor. All vital equipment is located in protected and inaccessible areas to make intrusion even harder. The containment is a steel structure that will dissipate heat to the environment using passive cooling for a design basis events, all safety-related systems are inside the containment. A basic design scenario, the large pipe break loss of coolant accident (LOCA), is rendered non-credible by design: there just is no large piping in the Reactor Coolant System (RCS) loop. All nuclear material is inside the containment – fuel in the reactor and the spent fuel in a special pool. There is enough water above the reactor core to ensure that the core is never uncovered and fuel temperatures never exceed normal operating temperatures. There is no boric acid in the reactor, which should increase the service life to an estimated 80+ years. The plant has a footprint of 4.5 acres, 6 for a two reactor installation. HOLTEC has designed the plant to make in-service inspections, as well as construction and maintenance as easy as possible. To facilitate shop manufacturing, all SMR-160 components are limited to 12 feet in diameter and practical maximum weights. Of course, cost will be a major issue for this reactor. At an estimated $1 billion for 160MWe spells $6250/kW, which is quite reminiscent of larger nuclear costs today. Maybe SteelBricks could bring construction costs down a little bit?
New fuel for CANDUs
Another really “boring” or “conventional” nuclear reactor is the CANDU reactor. It has been producing electricity for some 50 years. This type of reactor is interesting, because of its usage of pressure tubes instead of pressure vessels. The former are far easier to manufacture, which should remove on obstacle for a larger adoption of nuclear power. India has domestic versions of this reactor is now starting to build it in “fleet mode”. CleanCore has developed the ANEEL fuel for these reactors. Instead of natural uranium, it utilizes HALEU and thorium. This far more complex fuel - which is presumably far more costly than the usually used natural uranium fuel - enables higher burnup. And this translates to 7 times fewer refueling operations. At the end, there is 7 times less spent fuel on a volume basis. The nuclear physics of this fuel add a negative feedback loop that increases safety and should also help to make the CANDU easier to control, converting CANDUs to fairly advanced nuclear reactors.
Summary
The Ukrainian war put attention back on the topic of energy. There are quite a few ways that would offer us near-term relief. But the willingness to do it is still missing. The Malthusian dystopia of energy poverty and unilateral disempowerment is still holding sway over the population of the West. It looks like it will take some hardship to snap us out of that fantasy. I hope the industry will be ready to deliver when that happens.