Iran's nuclear facilities have been destroyed, but many experts think that its been able to hold on to some of its enriched uranium.

Here's why that 400+ kilograms of highly enriched uranium is REALLY important….

A brief 🧵 (WITH POORLY MADE GRAPHICS!) I’d actually been meaning to do this thread anyway, because there’s been a lot of confusion about uranium enrichment, and I thought it’d be helpful. But in the current context of this ceasefire it seems especially important.

So let’s start with how enrichment works....

OK, after reporting this out, I've got a few final thoughts on the B-2 strike on Fordo and whether the MOPs got through.

I think there's some really interesting details that have emerged and clarified my thinking... 🧵

npr.org/2025/06/25/nx-… First, a question I must ask myself (and that you should ask too) is have I become "man on the Internet" who thinks he knows more than the Pentagon....

I am somewhat fearful that doing my own math makes it look like I do, but I assure you I do not.

https://x.com/gbrumfiel/status/1935098092572786929

If a U. S. 'bunker buster' hits a nuclear site, what might get released into the air?

Very good fact-checking here by my colleague Nell Greenfieldboyce. Iranian enrichment facilities will not "blow up" in a mushroom cloud when they're struck...

npr.org/2025/06/18/nx-… Because the enriched U-235 is stored as a gas, its at far too low a density to start a criticality event. A bomb will simply disperse it around the local environment.

ANALYSIS: There is a LOT of stuff in the media right now about the Massive Ordinance Penetrator--The American bunker buster that might get used on Iran's deeply buried site at Fordow.

Can it hit Fordow? I'm not sure.

Here's why (WITH MATH). 🧵 OK, so before we even start, a disclaimer-- I'm a journalist, not a weapons expert. But I have reported on a similar topic a long time ago.

More on that later, but first, let's talk about the MOP.

It's a 30,000 lb (13, 600 kg) bomb built by Boeing and designed to hit bunkers.

BREAKING: A tiny town in North Carolina that’s just been devastated by hurricane Helene could end up severely disrupting the global supply chain for microchips and solar panels.

(By myself, @camilareads and Scott Neuman)

Short 🧵

npr.org/2024/09/30/nx-… The community in question is called Spruce Pine. It is America's sole source of high-purity quartz, and one of the only places that can supply high purity quartz to the world.

Or it was, until Hurricane Helene dropped a whopping 24.12 " of rain on it.

The @iaeaorg is closely monitoring fighting between Ukrainian and Russian forces near Russia's Kursk NPP.

This has the potential to develop into a serious nuclear emergency.

Here's some early thoughts in a short 🧵

https://twitter.com/iaeaorg/status/1821969222047821908

First, let's talk about the Kursk nuclear plant (KNPP hereafter).

The plant is located inside of Russia, about 100 km from the border with Ukraine. It consists of four units, two of which are currently operational (Units 3 and 4).

Iron Dome could be in big trouble if Hezbollah and Israel go to war. This is something I’ve been thinking about since Oct. 7, but I finally reported on it.

Nerdy 🧵 (followed by even nerdier philosophical🧵 about missile defense)

Or just read the story:
npr.org/2024/06/27/g-s… First of all, what IS Iron Dome? It’s actually a network of radars, targeting computers and missile interceptors spread across Israel. It’s intercepted thousands of missiles over the years. According to the company that makes it Rafael, it’s got a more than 90% success rate.

One week into the ground war in Gaza, here's what experts told me based on OSINT:

✅ The encirclement of Gaza City is a precursor for operations inside the city itself.

✅ The IDF has prob. not committed enough troops for a full occupation of GC.

...🧵

npr.org/2023/11/03/121… 🟡 Israeli troops appear to be operating under rules of engagement that allow significant civilian casualties.

❌ Some believe the willingness of Israel to tolerate high civilian casualties will be the "Achilles heel" of the entire operation.

npr.org/2023/11/03/121…

The Mysterious Case of The Stuff on the Roof!

This claim of objects on the roof of Zaporizhzhia Unit 4 has been doing the rounds this morning, but I'd urge healthy dose of caution.

Here's why... 🧵

https://twitter.com/KyivPost/status/1676855870582292480

So first off, where did this came come from? As far as I can tell, it was Radio Svoboda (Radio Liberty's Russian Service, I think?). They posted it on their Telegram channel earlier today and did a brief write-up here:

https://t.co/uc2l8Z6O2Gsvoboda.org/a/na-snimkah-k…

NEW: @TBowmanNPR has confirmed with a "U.S. Official" that an American surveillance satellite saw an explosion at the Kakhovka dam.

The official said that the image did not indicate who was responsible or whether the blast occurred above or below water. Although the official did not confirm the exact system used, I think that a SBIRS sat is most likely.

SBIRS stands for the Space-Based Infrared System. It is a vital part of the U.S. early-warning network designed to watch for a ICBM missile launch anywhere on earth.

So U.S. satellites spotted a blast at the Kakhovka Dam on the morning it collapsed, according to NYT.

I guess this would be SBIRS, right? It's certainly capable and weather conditions were favorable that night.

nytimes.com/2023/06/09/wor… Yesterday I reported on a faint seismic signature picked up by seismic arrays in Romania and Ukraine.

Together with less well verified on-the-ground evidence (text and video), it feels like there is a strong growing consensus the dam was blown.

npr.org/2023/06/08/118…

The Kakhovka Dam appears to be gone. This is going to have far-reaching consequences for weeks and months to come.

Here are some very early thoughts. (video via Ukrhydroenergo Telegram)🧵 First, a little background on what had been going on. Water levels plummeted in February and then surged in May to record highs.

Starship lost five of 33 engines on ascent. Pretty sure I saw one or two fail shortly after liftoff. Using lots of engines is a challenging design… so a failure on the first launch is definitely a learning opportunity.

https://twitter.com/gbrumfiel/status/1647946520682004483

NEW: This brief video of the Kakhovka hydroelectric power station offers definitive evidence for the condition and position of sluice gates at the reservoir.

🧵

https://twitter.com/novakakhovka_ua/status/1634654270791249920

First we can now definitively say that the damaged sluice gate in this image that emerged last week is sluice gate 1.

NEW: I've successfully geolocated the photo released yesterday of the Chinese spy balloon.

It was taken as the balloon floated just south of Bellflower MO on February 3.

Approximate location: 38°58'07.7"N 91°20'57.6"W Bellflower is just visible in the lower left hand corner of the image.

It's clearly identifiable from its distinctive reservoir and a nearby agricultural supply business just north of town.

*Sees military balloon news absolutely everywhere.*

*Looks around squinting, trying to read the room….*

WOULD YOU LIKE TO KNOW ABOUT THE TIME A BALLOON NUKED A BLIMP!?!

(of course you would… leessgooo! 🧵) A lot of people probably don’t know this, but blimps (officially “airships” or LTAs, but come on, everybody loves a blimp) were a big part of the Navy’s aerial fleet in the WWII.

And there was one thing they were very good at:

Anti-submarine warfare (ASW).

BREAKING: Satellite images and data obtained by @NPR show that Russia is draining a massive reservoir in southern Ukraine.

At stake is drinking water for 100,000s of people, agricultural production, and safety at Europe's largest nuclear plant. 🧵

npr.org/2023/02/10/115… The data is pretty stark. Since late last year, water levels have been plummeting at Kakhovka. They're now at their lowest levels in 30 years.

For perspective, this is like watching the Great Salt Lake in Utah empty out in a matter of months.

DEFINITIVE CHINESE SPY BALLOON THREAD!!!🎈

Nobody asked for it.

I'm doing it.

Here's everything technical you might want to know.... 🧵 OK, first off, what are we looking at?

According to James Flaten, a researcher at the University of MN, this is probably a stratospheric balloon. These balloons typically operate at between 80,000-120,000 ft.

This one has solar panels, so it’s been rigged for long-duration.

Computers are great at rocketry. 🚀

But ChatGPT and other generative AI programs seem to be terrible at it. 😖

I tried to learn why... 🧵

npr.org/2023/02/02/115… First off, why rocket science? It's because it is a profession that needs LOTS of computing power.
Since the early days of the Apollo program, computers have been used in design, testing and flight. "Computers are key," says MIT rocket scientist Paulo Lozano.

BREAKING: For the first time ever in a laboratory, researchers have generated more energy from fusion reactions than they used to start the process.

The total gain was around 150%.*

*caveats below 🧵

npr.org/2022/12/13/114… The achievement took place on December 5 at the @lasers_llnl (the National Ignition Facility).

NIF is a massive, $3.5 billion laser complex that's designed to zap very tiny things with very ginormous lasers.

BREAKING: An intelligence briefing slide obtained by @NPR through the Freedom of Information Act proves that President Trump tweeted classified material in 2019.

🧵

npr.org/2022/11/18/113… @NPR Here's what happened.

On August 29, 2019, an Iranian rocket blew up on the pad. Commercial satellite imagery from
@planet
showed there had been a catastrophic failure.

The next day, the President tweeted out an image that left experts stunned...