I toured South Texas Project nuclear plant years ago and remember being shocked that their turbine deck was open-air. "We don't really get inclement weather here", I was told. Unfortunately, unit 1 is down bc a feedwater pressure sensing line failed due to cold. Unit 2 at 100% Image
They gave me a nice hat though, which is by far the best swag I've gotten for just going on a plant tour Image
Even at 19, I had the sense that having an open-air turbine deck = wider potential for failures, even if bad weather is rare. After pushing the engineer, I was again told "these aren't safety-critical systems"... ok but if it fails, the reactor stops producing power (see: now)
Yeah, a sensor failure of a feedwater system is not a reactor safety issue. The reactor is fine. The issue is, we rely on reactors to produce electrical power, even (especially) in bad weather. Secondary systems are still critical in that regard
Here's an overhead view, you can see the turbine and generator on the roof. The one thing I have to admit, their turbines are a really pretty blue color, which you can sort of tell even here. Image
Not hating too much on the muted pastel yellows and greens that I've seen in many other plants (images not mine).... but I admit I like the bold blue better ImageImage
Importantly, Comanche Peak, the only other nuclear power station in Texas (which I have never been to) also appears to have an open-air turbine deck. Hopefully STP unit 2 and Comanche Peak (2 units) are both taking steps to prevent any more reactors tripping (going offline) Image
I don't want to give the sense that STP and other reactors with open turbine decks have never considered that equipment could freeze. Cold weather conditions are part of the severe weather conditions that nuclear plants must plan and prepare for. Image
I don't have access to STP procedures, but in a document submitted to the NRC, training guidelines say that personnel should be trained to conduct system walkdowns during freezing conditions, where sensing lines are specifically noted as a system to be monitored Image
Reiterating that I don't know the whole story here, besides what has been reported by the NRC and in media statements such as this one reported by @Atomicrod
atomicinsights.com/south-texas-pr… [slightly shortened] On Feb...
Given what has been reported, it's reasonable to think that more systems should be freeze protected going forward, and/or systems with the potential to fail due to cold should be identified & temporarily insulated faster in emergency conditions. But this was not an unknown risk
Well this is an interesting and entirely-different cold weather failure mode!
Hearing from a former senior reactor operator at STP that they're beginning the process of coming back online
Slight clarification of language: the system walkdowns I referred to here are required to be conducted annually by October 31st to identify and prepare systems for any freezing during the upcoming winter, not during a freezing weather event

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More from @nuclearkatie

18 Feb
Down to 1 km per second! Bonkers deceleration!
550 m/s...
Read 4 tweets
18 Feb
As we near closer to the touchdown of the #Mars2020 rover Perseverance, I want to note the key role that nuclear science plays here: Perseverance is powered by the radioactive decay of plutonium-238
The power source of Perseverance is not a nuclear reactor, and in fact Pu-238 isn't be a good choice for nuclear reactors because it doesn't readily fission. But its rate of radioactive decay is great for space exploration: it takes 87.7 yrs for half of the material to decay
#Mars2020 is powered by a Pu-238 radioisotope thermoelectric generator. The 87.7 year half life of Pu-238 means that RTG's can operate for a long time, for example Voyager 1, launched in 1977, is still sending signals back from its RTG. What % of the Pu mass at launch remains?
Read 6 tweets
17 Feb
Maybe it's just me, but I think many nuclear plants should do more to handle crisis comms on social media. This STP-1 trip is not a nuclear safety crisis, but misinformation is spreading that makes like it seems like it is. Plus the loss of power is especially poorly-timed
I've only seen a handful of quotes from STP comms, most notably the one shared in full by @Atomicrod
atomicinsights.com/south-texas-pr… Image
The website that Google previously linked when you search "South Texas Project" to is a broken Wix site. The other site I found (and recommended google change to) has a date of 2019 at the bottom and hasn't had a press release since October 2019
Read 6 tweets
18 Dec 20
This story is like falling into a dark hole. Every time you think you've hit the bottom, you take a step and fall further down

Literally everyone this story failed to protect workers. Cleanup of all kinds of hazardous waste is so, so fucked
Here's just a sampling of how fucked this story is
It looks like I'm sharing the whole article but I promise this is only a small sample!
Read 5 tweets
17 Dec 20
Laughing but... considering
Not really, but maybe someday when throwing around $250 isn't such a big deal
Only rated to 35 degrees which kinda sucks (I've camped in places that dropped below 35F in the month of August, for example), but I would absolutely put it on my future purchases list if it was rated at 0F
Read 5 tweets
1 Jul 20
🚨🚨Time for another @ANS_org webinar hosted by @ans_ymg🚨🚨

Let's learn about @PNNLab for the fifth "Spotlight on the National Labs" webinar!! You can register to attend here (starts at 13:00 EDT) or follow my thread below for the tl;dr 🧵👇us02web.zoom.us/webinar/regist…
We're hearing from EIGHT different @PNNLab employees, including lab director Steven Ashby! Ever wondered what kind of nuclear science and engineering work is going on at Pacific Northwest National Lab? Recording will be available to those who register us02web.zoom.us/webinar/regist…
PNNL is located in Richland, WA and is one of several laboratories that traces its roots back to the Manhattan Project. The lab has about 4700 staff, with about a quarter of the budget each going to Energy & Environment, National Security, and Science
Read 19 tweets

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