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Edwin Lyman

@nucsafetyucs.bsky.social
621 followers 52 following 305 posts

Director of Nuclear Power Safety, Union of Concerned Scientists, Washington, DC.

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Edwin Lyman @nucsafetyucs.bsky.social · 23h
www.nytimes.com/2026/10/04/w...
nytimes.com
Superpowers Race to Put Nuclear Reactors on the Moon
The United States wants a reactor on the moon by 2030. A Russian-Chinese alliance is working on one for 2036. Some leading scientists say the danger is great.
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Edwin Lyman @nucsafetyucs.bsky.social · 25/09/2026
Another screwup at the troubled River Bend #nuclear plant in #Louisiana: NRC investigators found that a supervisor gave a key controlling critical digital assets to an uncleared contractor, along with his access badge: a major #cyber security breach. www.nrc.gov/docs/ML2623/...
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Edwin Lyman @nucsafetyucs.bsky.social · 25/09/2026
On Wednesday workers at the decommissioning San Onofre #nuclear plant in #California accidentally dumped 5000 gallons of wastewater with a tritium concentration about 3000 pCi/liter into the Pacific Ocean, which is within drinking water standards but still not a good thing to do.
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Edwin Lyman @nucsafetyucs.bsky.social · 22/09/2026
The NRC has cited the North Anna #nuclear plant in #Virginia for a Green security violation. Given that the agency has weakened its standards, such a finding has to be more serious than it used to be to reach this threshold. www.nrc.gov/docs/ML2626/...
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Edwin Lyman @nucsafetyucs.bsky.social · 21/09/2026
Well, that didn't take long ... Holtec has released a statement about the "pause" in fuel loading due to the dropped #nuclear fuel assembly. They say it didn't trigger @NRCgov safety reporting requirements, which is why they kept silent (for over two weeks).
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Edwin Lyman @nucsafetyucs.bsky.social · 21/09/2026
Kudos to appropriations committee ranking members Sen. Patty Murray and Rep. Marcy Kaptur for demanding information from the NRC on the impact of Trump-directed changes to #nuclear power regulation on public health, worker safety, and the environment. www.appropriations.senate.gov/imo/media/do...
appropriations.senate.gov
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Edwin Lyman @nucsafetyucs.bsky.social · 21/09/2026
On Friday an Unusual Event was declared for nearly two hours at the Palo Verde #nuclear plant in #Arizona due to what was determined to be a "security condition not involving hostile action." (Those darned kids again?). All three reactors were operating at full power.
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Edwin Lyman @nucsafetyucs.bsky.social · 20/09/2026
1/2: An eagle-eyed observer brought to my attention a post on Reddit alleging that Holtec dropped a partially burned #nuclear fuel assembly during its fueling of the Palisades reactor in #Michigan more than two weeks ago, yet nothing but silence from either the company or the NRC.
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Edwin Lyman @nucsafetyucs.bsky.social · 18/09/2026
Hah. Different picture on the NRC website today. Perspective is still skewed but there is only one cooling tower now and the gibberish insignia is gone. Was someone listening?
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Edwin Lyman @nucsafetyucs.bsky.social · 17/09/2026
More bad news for the nuclear scammers this week. I was wondering why there was no visible nuclear plant construction going on months after Terrapower got a construction permit. www.bizjournals.com/washington/n...
bizjournals.com
Bechtel warns of 200 layoffs at Reston HQ after split with Bill Gates-backed nuclear project - Washington Business Journal
Engineering and construction giant Bechtel Corp. is warning of up to 200 layoffs at its Reston headquarters after an apparent falling-out with the developer of a nuclear power project in Wyoming.
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Edwin Lyman @nucsafetyucs.bsky.social · 17/09/2026
The NRC just launched its new website design. Why am I not surprised that it has a cheesy AI-generated image at the top (why does the nuclear plant have two cooling towers but only one reactor? Why do the jacket insignias have gibberish on them?) LMAO.
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Edwin Lyman @nucsafetyucs.bsky.social · 17/09/2026
Not exactly a surprise. startupfortune.com/holtec-pulls...
startupfortune.com
Holtec Pulls Its $900 Million Nuclear IPO as AI Bubble Fears Spread - Startup Fortune
Holtec Nuclear suspended its $900M IPO as peers Standard Nuclear and X-Energy trade 21% and 37% below their listing prices amid AI bubble fears.
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Edwin Lyman @nucsafetyucs.bsky.social · 15/09/2026
At today's NRC Advisory Committee on Reactor Safeguards meeting on the Long Mott pebble-bed reactor application, member Dave Petti revealed that the similar Chinese HTR-PM experienced breakage of some of its non-fuel graphite pebbles because of manufacturing defects. Hadn't heard that one before.
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Edwin Lyman @nucsafetyucs.bsky.social · 13/09/2026
Thank you for inviting us to present our views on your podcast.
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Edwin Lyman @nucsafetyucs.bsky.social · 10/09/2026
Here's my new piece on the state of #nuclear reactor security on the 25th anniversary of 9/11. blog.ucs.org/edwin-lyman/...
blog.ucs.org
The NRC is Regulating Nuclear Security like it’s September 10, 2001—And We Should All Be Concerned
On the morning of September 11, 2001, I was preparing to leave my Washington, DC apartment for an appointment when the phone rang. It was just after 9 AM.   On the line was my boss at the time, Pau...
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Edwin Lyman @nucsafetyucs.bsky.social · 05/09/2026
Energoatom warns on its Telegram channel that the Russian occupiers of the Zaporizhzhia #nuclear plant are running the emergency diesel generators in non-standard modes during the current extended loss of offsite power, increasing the risk of common-cause equipment failures.
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Edwin Lyman @nucsafetyucs.bsky.social · 04/09/2026
Yesterday the Dresden-2 #nuclear reactor in #Illinois was manually scrammed at full power after an instrumentation failure caused control rod movement.
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Edwin Lyman @nucsafetyucs.bsky.social · 02/09/2026
Holtec is boasting about loading fuel into the Palisades #nuclear reactor in #Michigan, yet it just received 2 violations for failing to protect its workers from high airborne radiation levels. And we are supposed to trust them to keep the public safe ... www.nrc.gov/docs/ML2624/...
nrc.gov
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Edwin Lyman @nucsafetyucs.bsky.social · 02/09/2026
At the ACRS X-Energy meeting yesterday, NRC staff said that the Seadrift, #Texas Long Mott construction permit application safety analysis had improperly screened out 47 (!) accident sequences that should have been considered. Your tax dollars paid for this.
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Edwin Lyman @nucsafetyucs.bsky.social · 02/09/2026
Walt Kirchner of ACRS just confronted X-Energy about why the company is keeping the temperature of its TRISO fuel irradiation testing "proprietary" when it is critical for the public to understand the safety of its reactor with its lack of containment. They are hiding something.
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Edwin Lyman @nucsafetyucs.bsky.social · 31/08/2026
Is reality finally catching up with Oklo? www.utilitydive.com/news/pjm-okl...
utilitydive.com
PJM drops Oklo advanced nuclear project from interconnection study cycle
Oklo asked the Federal Energy Regulatory Commission to order the PJM Interconnection to reinstate its 750-MW, mixed-technology project. PJM reportedly told Oklo that it never showed the project could ...
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Edwin Lyman @nucsafetyucs.bsky.social · 28/08/2026
Add Sen. Patty Murray (D-WA), Vice Chair of Senate Appropriations, to the list of folks who have been rebuffed by the NRC when requesting an extension to the comment period for its proposal to allow more Americans to get cancer from nuclear facilities. www.nrc.gov/docs/ML2621/...
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Edwin Lyman @nucsafetyucs.bsky.social · 27/08/2026
So let's do the math here for the Army JANUS program. $2.2 billion of our money for 5 microreactors with a total power capacity of 32 MW-electric. That works out to a mere $68,750/kW. That makes the $15,000/kW Vogtle disaster look like pocket change. www.army.mil/article/2948...
army.mil
Army reaches agreement with private industry for nuclear micro-reactors
WASHINGTON — The Department of the Army is announcing today that the Janus Program has selected five nuclear energy vendors, and five initial locations.
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Edwin Lyman @nucsafetyucs.bsky.social · 26/08/2026
OMG!!! Financial support from Oklo, but "editorially independent"? LMAO
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Edwin Lyman @nucsafetyucs.bsky.social · 26/08/2026
Excellent article in @nature.com by Peter Fairley on the challenges to the NRC's status as an independent #nuclear safety regulator: www.nature.com/articles/d41...
nature.com
Are pro-nuclear politics a threat to public safety?
Oversight agencies suddenly face pressure to rapidly assess a range of relatively untested reactor designs.
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Edwin Lyman @nucsafetyucs.bsky.social · 14/08/2026
Yesterday operators manually scrammed the St. Lucie-1 #nuclear reactor in #Florida at full power after three (!) control rods accidentally dropped into the core. The reactor is still down today.
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Edwin Lyman @nucsafetyucs.bsky.social · 09/08/2026
www.usatoday.com/story/news/n...
usatoday.com
America's energy future? Gates, Buffett and a Wyoming town go nuclear
A Wyoming town is building a new nuclear plant backed by Bill Gates as coal jobs fade and residents remain split.
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Edwin Lyman @nucsafetyucs.bsky.social · 01/08/2026
www.nbcnews.com/world/europe...
nbcnews.com
Hungary braces for a full shutdown of nuclear plant as the Danube River hits record lows
The Paks nuclear plant, located around 50 miles south of the capital Budapest, could face a shutdown for the first time in its 44 years of service due to a lack of water for cooling.
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Edwin Lyman @nucsafetyucs.bsky.social · 01/08/2026
Some smart folks in #Delaware! www.delawarebusinessnow.com/news/technol...
delawarebusinessnow.com
Task force rules out  small nuclear power plants  as short-term solution
The final report of a task force studying small nuclear plants did not close the door on future use, but concluded that the technology wouldn’t address near-term power shortages.
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Edwin Lyman @nucsafetyucs.bsky.social · 31/07/2026
Bomb-usable uranium mystery solved: Now we know the identity of the irresponsible company seeking an NRC permit to build a highly enriched uranium-fueled reactor: Space Ocean Corporation in Brownsville, #TX. They want to build another KRUSTY. www.nrc.gov/docs/ML2621/...
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Edwin Lyman @nucsafetyucs.bsky.social · 31/07/2026
On July 19 a Troxler moisture density gauge containing 8 millicurie cesium-137 and 40 mCi americium-beryllium sources was stolen from a locked garage in Johnstown, #Ohio by someone in a ski mask using bolt cutters. Sure sounds like the gauge was targeted for theft -- but why?
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Edwin Lyman @nucsafetyucs.bsky.social · 30/07/2026
The NRC has denied requests to extend the 45-day comment period on its dreadful radiation rule by the Health Physics Society (over 2000 members); AFL-CIO (nearly 15 million members); and the state of Connecticut (population 3.7 million). It does not care about the what the public has to say.
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Edwin Lyman @nucsafetyucs.bsky.social · 22/07/2026
Not sure how I missed this, but here is the reason for the comment yesterday by Jennifer Wheeler of TRISO-X about inadequate contractor oversight. The company approved application of defective welds and then failed to inspect them. A rush to failure. www.nrc.gov/docs/ML2615/...
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Edwin Lyman @nucsafetyucs.bsky.social · 21/07/2026
BREAKING NEWS: Michelle Sampson of NRC just said they have heard from a potential advanced reactor applicant who wants to use bomb-usable HIGHLY ENRICHED URANIUM in their design. This is beyond the pale.
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Edwin Lyman @nucsafetyucs.bsky.social · 21/07/2026
Jennifer Wheeler with the TRISO-X #nuclear fuel facility being built in #Tennessee just said at the NRC briefing that the company "underestimated" the level of contractor oversight necessary to ensure requirements were being met. Hmm, wonder what the story is ...
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Edwin Lyman @nucsafetyucs.bsky.social · 21/07/2026
Rita Baranwal of Radiant #Nuclear just said at an NRC Commission briefing that her company plans to deploy its 1-MW, containment-free microreactors "adjacent to urban areas" and wants them to power building HVAC systems. Which city? Crazytown.
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Edwin Lyman @nucsafetyucs.bsky.social · 17/07/2026
I hear that the company has an innovative linear plasma design that should give @helionenergy.bsky.social a run for its money. wedc.org/realta-fusio...
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Edwin Lyman @nucsafetyucs.bsky.social · 17/07/2026
For anyone interested, I posted this paper on arXiv yesterday: arxiv.org/abs/2607.15250
arxiv.org
Equivalence of the Compton and Bethe-Feynman Yield Formulas
The Bethe-Feynman formula has proven useful for estimating the explosive yields of simple fission weapons. However, derivations of the Bethe-Feynman formula found in the open literature utilize approx...
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Edwin Lyman @nucsafetyucs.bsky.social · 09/07/2026
On June 29 the Curium radioisotope facility in #Indiana experienced another contamination event when a technician dropped a vial containing 6.53 curies of lutetium chloride. The count rate on the pants, shoes, and socks of the technician went off the instrument scale.
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Edwin Lyman @nucsafetyucs.bsky.social · 06/07/2026
On Friday the Fermi-2 #nuclear reactor in #Michigan automatically scrammed from 83 percent power after the loss of a transformer caused a loss of power to both reactor protection system electrical buses. The reactor is still down today.
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Edwin Lyman @nucsafetyucs.bsky.social · 04/07/2026
www.cbsnews.com/boston/news/...
cbsnews.com
"No danger" after fire on Seabrook, NH nuclear power plant property, police say
There was a transformer fire on the Seabrook, New Hampshire nuclear power plant property. The nuclear facility was not impacted.
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Edwin Lyman @nucsafetyucs.bsky.social · 02/07/2026
I just noticed that Plant Vogtle Units 1 and 3 in #Georgia both reduced their power level from full power to 55 percent yesterday. Heat-related, I assume.
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Edwin Lyman @nucsafetyucs.bsky.social · 02/07/2026
To "unleash" #nuclear energy, the Energy Department and the NRC are taking a wrecking ball to nuclear safety, security, and radiation protection standards that were carefully developed over the decades, often in response to painful lessons. So why do nuclear power stocks keep falling?
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Edwin Lyman @nucsafetyucs.bsky.social · 01/07/2026
NEWS FLASH: The NRC has released the prepub versions of two major proposed rules: one on "reforming and modernizing the radiation protection framework" and the other on "modernizing reactor licensing, oversight, and safety practices." www.nrc.gov/docs/ML2618/... www.nrc.gov/docs/ML2617/...
nrc.gov
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Edwin Lyman @nucsafetyucs.bsky.social · 01/07/2026
Of course, if you move the goal posts close enough, you can achieve anything! The E.O. clearly states the goal applies to reactors outside of the national laboratories. That's the part they like to leave out. Look it up. www.energy.gov/articles/us-...
energy.gov
U.S. Department of Energy Meets President Trump’s Goal, Delivers Third Advanced Reactor Criticality
Deployable Energy’s demonstration reactor, Unity, successfully achieved criticality, marking the fulfillment of President Trump’s executive order directing DOE to authorize three advanced reactors wit...
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Edwin Lyman @nucsafetyucs.bsky.social · 29/06/2026
The shameful Trump v. Slaughter decision ends the independent, expertise-driven regulation of #nuclear power that the US has benefited from for over 50 years. We are no longer in compliance with Article 8 of the Nuclear Safety Convention. Other nations should take heed.
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Edwin Lyman @nucsafetyucs.bsky.social · 29/06/2026
www.npr.org/2026/06/29/n...
npr.org
Red, white and glowing blue: Trump's push for new reactors reaches the finish line
A program initiated by the Trump administration has allowed small companies to rush their testing of several new nuclear reactor designs. Some worry that safety is being compromised.
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Edwin Lyman @nucsafetyucs.bsky.social · 28/06/2026
The fire danger in Orangeville, Utah, location of one of the Energy Department's misguided #nuclear reactor "pilots," is "extreme." I wonder how well-validated the wildfire safety plan is for this reactor, which a few days ago allegedly operated at 100 kilowatts for 24 hours.
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Edwin Lyman @nucsafetyucs.bsky.social · 25/06/2026
News flash: Nuclear Regulatory Commission staff are recommending a construction permit be issued for the Clinch River BWRX-300, even though they can't say the application methodology is suitable to demonstrate containment safety. Another can to be kicked down the road. www.nrc.gov/docs/ML2616/...
nrc.gov
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Edwin Lyman @nucsafetyucs.bsky.social · 25/06/2026
The Nuclear Regulatory Commission 2025 security report to Congress is out. Force-on-force inspections took place at 17 #nuclear plants. Out of 30 exercises, two were ineffective (meaning that the mock adversary force was able to simulate a meltdown), and one was marginal. www.nrc.gov/docs/ML2606/...
nrc.gov
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