Alex Mercer

@scaryjellomj @KairosPower Cost certainty = we’re highly certain that it’s costly

@KairosPower Build test learn repeat but your architecture relies on extremely expensive fuel, weapons quality lithium halide corrosive bath, and doesn't seem remotely competitive.

How do you drive greater cost certainty for new reactors? Build. Test. Learn. Repeat.

@yasir_fission This is not a commercial nuclear reactor or anything resembling one. It’s yet another zero power criticality experiment to join the hundreds of others at national labs and universities. The only reason you were able to build it so fast is because it’s not a real power reactor.

We just built our first nuclear reactor, at an impossible speed - 14 days: completed PDSA - 36 days: finished construction - 28 days: built the reactor - 10 days: assembled on site Core goes in after final DOE approval. Speed without sacrificing safety.

@MattLoszak This is nothing more than a science experiment

Today, we unveiled our completed Critical Test Reactor facility. We will be turning this reactor on (a “zero power criticality”) well before July 4th! This is a commercial-scale system with enough fuel to produce 10 MW of electricity, and will someday soon power a co-located data center from one of our partners. Here’s what people saw today at our ribbon cutting: ✅ Reactor vessel ✅ Graphite as moderator ✅ Instrumentation and control ✅ Concrete shielding ✅ Building with crane ✅ Control room All designed and built by Aalo. And the nuclear fuel will be arriving any day now. One last step remains: the final DOE approval to turn the reactor on, which we expect to receive soon. DOE has been an incredible partner in this 2.5 year journey, working hard to support a number of companies pushing to advance US nuclear energy. Follow us to be the first to know when we turn this reactor on!

@BumfOnline @bigthink Source: icrp.org/consultation_v…

@AlexMercer8005 @bigthink Yes. For political reasons.

The likelihood of a catastrophe caused by a terrorist at a U.S. nuclear power plant is as close to zero as humanly possible. bit.ly/3JKtHij

@BumfOnline @bigthink Actually, for political reasons, Japan made the exclusion zone *smaller* than scientists recommended, because they knew that being unable to return home was traumatic and very unpopular. The ICRP recommended dose limits of 1 mSv/yr. Japanese officials decided to allow 20 mSv/yr.

@BumfOnline @bigthink You realize a sizable portion of that exclusion zone is still in place to this day, right?

@AlexMercer8005 @bigthink We all know more than they did now. They overreacted. The displacement was political, not risk-informed.

@BumfOnline @bigthink As for the Fukushima question, I’m amazed that you think you know more than the thousands of health physics experts, regulators, and policymakers who decided the size of the exclusion zone. You may be right about the initial evacuation, but not about the permanent displacements.

@AlexMercer8005 @bigthink For one thing, soent-fuel casks aren’t pressurized within a reactor. For another, the displacements at Fukushima were precautionary and very likely resulted in far more harm than any dose exposure they could have received.

@BumfOnline @bigthink I’m talking about the spent fuel *pools* for wet fuel storage during the ~5-10 year cooldown period between being unloaded from the reactor and being placed in a dry cask. Needs to be constantly cooled and represents a source term an order of magnitude larger than a reactor core.

@BumfOnline @bigthink Yeah, right. 130,000 initially evacuated from Fukushima and 30,000-40,000 remain permanently displaced 15 years later. All of this with dose regulations significantly less strict than the NRC. But sure, tell me more about how radioactivity releases aren’t a concern for the public

@AlexMercer8005 @bigthink If this was released, it would cause local contamination, nothing more. A concern for the plant but no concern for the public.

@DNgenuity48883 @bigthink I’m not sure what point you’re trying to make here. Spent fuel is very, very dangerous if not continuously cooled. Fresh fuel is largely benign and doesn’t need to be cooled. It’s the radioactive fission products that make fuel dangerous.

@AlexMercer8005 @bigthink As if spent fuel is a safety concern. It is SPENT after all… the misleading NCIS episode and the completely scientifically baseless movie that was made about a “nuclear train” withstanding.

@johnrhanger @EnergyLawJeff @mattyglesias Interesting that people used to pay so much for electricity. Sooner or later we may need to hit those prices again. We’re not building much firm generation these days - coasting off nuclear plants built in the 1970s with very low operating costs. Those plants can’t last forever.

@EnergyLawJeff @mattyglesias Here is the table comparing PA monopoly prices in 1996 to both competitive utility default prices and electricity supplier prices (shopping):

With all due respect to @mattyglesias, anyone reaching even the tentative conclusion that fully returning to integrated monopolies is the answer to our present circumstances hasn't spent enough time learning the history of the electricity industry. 1/

@bigthink (2/2) These changes suggest that traditional containment building designs with reinforced concrete may not in fact be sufficient to withstand all credible impacts from a large modern jet airplane, which calls into question the resiliency of existing plants.

@bigthink (1/2) If it’s true that all existing plants are impervious to aircraft impacts as you claim in the article, then why was the Aircraft Impact Assessment rule instated by the NRC in 2009? And why did it result in containment building design changes for the AP1000 and ABWR designs?

@JosephSomsel @scaryjellomj Very interesting. Yeah with all of those redundancies it sounds like it would be a pretty vanishingly small frequency branch in the PRA even before considering physical conditions that would minimize consequences.

Let me expand on item 3 - "(3) Is it practically workable to prevent turbine spinup just by inspections?" I didn't answer completely by essentially skipping ahead. We've triple redundant and diverse systems to prevent overspeed. There is a separate digital overspeed trip for main steam, a standard governor overspeed trip, and a passive mechanical overspeed trip. (This is from memory.) I had originally answered about mechanical failure of the turbine rotors which had been the historical problem. Turbines had big steel discs with slots to attach the individual blades. There had been stress corrosion cracking in the discs here the blades slipped into slots in the disc. These stress concentration points were redesigned and better steel was used in the discs.

Help me create a pinned thread where we log ideas about what NRC requirements could be rolled back by the Trump administration to reduce nuke plant operator expenses. Not vague ideas like 'End ALARA' but real things like 'reduce security to the size of a small town PD'.

@JosephSomsel @scaryjellomj Interesting stuff, thanks! It would be nice to be able to arrange turbines in a parallel with reactor buildings again like we used to - clearly a slightly more economic configuration given that coal plants and old nuclear plants generally chose that arrangement. What’s NDTP?

1) The PRAs I've seen put the core damage frequency risk very very low from ATWS. 2) we've identified the drivers of NDTP in the original RPV steel and in the beltline welds (sulfur.) 3) EPRI did good work on the blade-to-disc vulnerability and turbine manufacturers have implemented.

@JosephSomsel @scaryjellomj Questions: (1) Why? This has been a real concern at plants like Browns Ferry, LaSalle and others. (2) Aren’t the RPV coupons strictly beneficial for long-term SLRs? (3) Is it practically workable to prevent turbine spinup just by inspections? (4-6) Don’t know much about these.

Off the top of my head. 1) Never thought much of ATWS. 2) Relax the RPV vessel coupons program. 3) Allow island plant arrangements so peninsula arrangements no longer mandated if you have regular turbine inspections. 4) no spent fuel rack sprays. 5) loosen the Possible Max Precipitation (PMP) flooding analysis. 6) don't need ACRS review for each application.

@PattyDurandGA 35 MW thermal, no less! After thermodynamic efficiency losses it’ll be <= 15 MW of electricity.

35 MWs? Hahaha that’s really gonna do something….

@Nuklearia @MattLoszak Decarbonization is a very complex optimization problem with many technology options available, and it’s not exactly crystal clear that new nuclear makes sense in most countries, although it does make sense in some. See this study for the U.S. case: docs.nrel.gov/docs/fy22osti/….

@AlexMercer8005 @MattLoszak You shouldn't have to pay market prices for the capital costs of foundational infrastructure that is also decarbonising full time, when your goal is to decarbonise. This makes no sense at all when you on the other hand pay heavy annual subsidies for the part time decarbonizers.

Can nuclear get below 2 - 3 c/kWh? Most people think it's impossible, so we built an interactive cost model to debate on a more granular level. Here's what must be true, line by line, for < 3 c/kWh nuclear. In my view it's surprisingly feasible... 👇🧵

@Nuklearia @MattLoszak Show me a credible capacity expansion model for deep decarbonization that says we should build new nuclear at anywhere close to the cost of Vogtle in the U.S. or Flamanville in France. Or hell, even a factor of 2-3x cheaper than those plants.