Amazon-backed X-energy bags $700M more for itty-bitty nuke reactors that don't exist yet Months after Amazon joined a half-billion-dollar funding round for next-gen modular nuclear startup X-energy, the biz has announced a supplemental Series C-1 raise - despite its fission reactor design remaining unproven. X-energy today secured $700 million from new backers to support its small modular reactor (SMR) development …
There is an SMR currently under construction just east of Toronto, with 3 more planned to be built alongside. The first one will be on line and delivering power to the grid before X-Energy's most optimistic projections for their first one (which hasn't even got construction plans yet).
However, it uses conventional low fuel available from commercial suppliers, instead of the special medium enriched proprietary fuel such X-Energy is using. A single SMR of this type will also put out about as much power as 4 of X-Energy's. Or to put it another way, you would need 16 of X-Energy reactors to equal 4 of the ones being built in Canada. I doubt that X-Energy can deliver their reactor for a quarter of the capital investment, and I doubt that their proprietary fuel will prove to be cost competitive with conventional reactor fuel.
What is more, X-Energy claim their reactors don't need containment buildings. I would be surprised if they got approval to operate a reactor based just on their fuel needing no containment, especially as they only claim that their fuel pellets are only rated to contain 99.99% of fission products. I'm not sure that conventional fuel pellets are significantly worse.
The Germans built a pebble bed reactor (which is the generic name for these things) in the 1960s. It was tested with both BISO, and later TRISO (the type X-Energy intend to use) fuel, and also gas cooled with helium.
It was a failure to put it mildly. Temperature control was difficult, and the fuel pebbles emitted contamination and whole system was contaminated by fine radioactive dust from the fuel. Radioactive material leakages contaminated the site, and the whole thing ended up having to be filled with concrete to try to fixate the contamination in place. Decommissioning and dismantling are apparently expected to take until the end of the present century.
Not deterred by this, the Germans built a second, larger version. This suffered from even more problems. Dust and debris from the pebbles (they circulate through the system) plugged cooling channels, and the pebbles themselves would get stuck. The Germans finally gave up on the idea at the end of the 1980s. Several other countries have built systems since, none has been especially successful.
All reactors of this type use graphite in their outer layers as a moderator. This graphite coated fuel is one of the designs weaknesses, not a strength as they like to put it. It was graphite moderator fires which caused the Windscale and Chernobyl accidents, not fuel melt downs.
The pebble bed reactor is one of those things which sounds simple when sketched on the back of an envelope. However, they have all been complex and difficult to operate in practice once the real world intrudes into theory.
My opinion is that they offer no real advantages in terms of safety, cost, or simplicity, and are a technological dead end.
The main attraction that these and other unconventional SMRs offer is to the companies that will supply the highly specialized proprietary fuel for them. It will be a license to print money for the company that holds the rights to the fuel.
The point of Small Modular Reactors is the "modular" bit. It applies the same sort of modular construction techniques used in the latest shipyards to build ships in blocks which are then assembled ready to go rather than building piecemeal on site. Conventional reactor technologies can be adapted to modular construction without having to use totally new reactor designs or exotic fuels. I expect that these are what will be commercially successful.
You are forgetting that there are very distinct flavors of High Temperature Gas cooled Reactors (HTGR). One is the pebble bed, and the other is General Atomics design where the fuel pellets are encased in pyrolitic graphite that placed in prisms of graphite that serve as the moderator. The prototype HTGR at Peach Bottom could survive a loss of coolant event by simply cooling the outside of the pressure vessel. The larger HTGR's would require some sort of back-up cooling system, but the thermal mass in the reactor allowed for several hours before the back up cooling needed to be activated.
One advantage of a water moderated reactor has over a graphite moderated reactor is that the water pretty much grabs all of the iodine given off by the fuel in a meltdown or partial fuel melting.
"... It was graphite moderator fires which caused the Windscale and Chernobyl accidents, not fuel melt downs. ..."
Nope.
Sure, the graphite caught fire at Windscale (which is now called Sellafield, but it's the same place). But that wasn't the cause of the accident, it was a symptom.
Rather than catching fire, much of the graphite at Chernobyl was propelled through the roof by the steam explosion - which again was a symptom, not a cause.
In both cases the cause was negligence. In the case of Chernobyl, the level of negligence was absolutely astounding.
At school I wrote an essay where I imagined a future where every home would have a fission powered micro fuel cell in their home, sitting in the place once occupied by the gas boiler.
Powered by replaceable cartridges that last five years and have to be rented.
Absolute fantasy of course. But back then, a tiny portable device that could be used to make video calls to virtually anywhere in the world in the hands of practically everyone was absolute fantasy.
Total rip-roaring BS! Lockheed Martin has had their 40 MEGAWATT small form factor reactor for almost TEN YEARS now! It's barely the size of four home refrigerators (8 cubic metres) and has been powering some secretive US Navy hardware and some specialized Fixed Base Installations for about the same 10 years now! Looks great! No radiation leaks and works JUST FINE for continuous output at said 40 Megawatts. Some eggheads in a certain secretive location (Utah) even put one on a plane!
They can be aggregated together for GIGAWATTS of city-grid-scale continuous output. The reactor, with the appropriate fueling cycle schedule will physically last around 50 years with almost no degradation to the vessel walls. Radiation-induced Hydrogen embrittlement is no longer a big issue! Even the previously problematic Plasma arcing/pitting issue is now mostly solved.
I know all this on a personal level .... SO THERE YOU HAVE IT!
Get that fancy pants golf-hound Donald J. Trump to declassify it all! It's Not That Hard.
He just needs to sign another Executive Order to declassify the Lockheed Martin Small Form Factor Reactor System and get is sold for public use!
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