The Accident That Proved Nuclear Energy Is Safe

[@lindsaydempsey5683]

The teaser at the front end definitely gets my vote. TMI and Fukushima Daichi are living proof that even on their very worst days, western nuclear power plants are very very safe. Really looking forward to absorbing the the rest of the episode.

[@pazsion]

the pacific continues tongo extinct navy and marines die from cancers along with civilians that enjoy tge beaches and swim in the pacific. fukushima accelerated the current 6th mass extinction event

[@lowstrife]

Holy shit. James. I've listened to Nicholas Means and his presentation about TMI (and all his other talks), which is a great topical level overview of the accident sequence. But this is a GREAT second dive into it at another level deeper of what happened here. Great storytelling to an audience who isn't a nuclear engineer.

[@mykhailobortnik-api]

James, your insights in this episode are spot-on! Your deep understanding of the technical and operational aspects, as well as the broader implications of Three Mile Island, is truly impressive. It’s amazing how you explain complex topics so clearly while hitting the nail on the head about industry challenges, safety, and public trust. I’ve learned so much from listening to you-your commentary really brings out lessons that feel essential for anyone in nuclear. Thank you for sharing your expertise

[@rebeccanobbs3747]

Awesome discussion. As an operational power engineer I really enjoyed how James broke down the sequence of events and explained the nuclear and mechanical engineering concepts in simple language.

[@microburn]

Wow the decouple team has really stepped up their game with this one.

[@chrisjohns38]

When I studied what happened at TMI-2, I concluded that we would not have ever heard about the incident if the operators would have gone to the local strip club and gotten drunk instead of taking ANY actions to deal with the stuck PORV. Prove me wrong!

[@tgmct]

As a former NPP supervisor, what transpired at TMI2 makes me sick. I’ve never had any experience with a B&W plant. But it is clear that there were a number of design flaws before the event even occurred. Additionally, the plant operator was not real keen with maintenance and would even allow defeating a key safety system while the plant was operating. I think that the best that can be said is that the system didn’t kill anyone in spite of itself. All that said, I need to address the restart proposal with TMI1. I suspect that this plant was defueled and kept in a cold wet layup state ever since. After the TMI incident, all of the other plants in the country have gone through extensive remediation programs. Billions of dollars have been expended and a number of these plants have even been decommissioned and completely disassembled. I don’t know if TMI upgrades were ever performed to unit 1, but I doubt it. I also don’t know if other B&W plants of this vintage have had life extension programs approved and applied. I’m not currently an advocate for continuing commercial light water PWR’s until a reasonable solution to high level waste storage and containment can be devised, agreed upon, and implemented. Otherwise, I’m a proponent for thorium breeder reactor technology which has far safer systems than PWR’s and dramatically reduced high level waste generation.

[@Hazmatt3446]

I'm hoping you can answer my question... Former nuke here that never operated commercial plants... how could the steam generator go dry if the turbine had tripped? At that point, hP drains. In a scrubber tank, if it exists, would be the only load on the mainsteam system. Did you explain what I am missing? Also, to my knowledge, no one has built. It's an add scale Thorium, reactor. What am I missing in that regard, please. Thanks,

[@GreezyWorks]

Containment buildings are definitely underrated.

[@thomasathorne828]

Comparing power density to the Sun is a bit misleading really---famously the Sun isn't very power dense at all (less so than a compost heap, if I recall correctly) but it makes up for that just by being very, very big. Maybe compare the power density to the combustion chamber in an ICE, jet engine or rocket engine? Or even the mitochondrial matrix in a muscle cell? Great episode though! Very interesting.

[@Mark-hd8io]

Didn't he say at the center of the sun?

[@mhirasuna]

Great episode. James has explained how TMI proves the effectiveness of the safety systems of a NPP. However, Fukushima showed that even when those safety systems failed, no one died. Bret Kuglemass has questioned the need for safety which make nuclear power unnecessarily expensive. Just how dangerous is a meltdown? Is it really worth all that cost to keep it contained?

[@Discoworx]

Knows his stuff and is a great communicator. Fascinating and educating!

[@jaypeltz2587]

fantastic episode, I learned so much and can't wait for the next one.

[@melhand3990]

Brilliant explanation. It was a pity at the time when the pressure valve had failed on several occasions that the design of the valve was not corrected. The fact that the auxiliary line valve on the blue line was not opened manually could have avoided the melt down. I know hindsight is 20 20. Decouple have done it again.

[@waywardgeologist2520]

Thank you for this code in depth look at the accident. Now I wish you would do a video on the safety systems for a molten salt reactor.

[@jeffheiner]

Thank you for an amazing explanation of what happened at TMI. 300,000 times higher energy density than the core of the sun!!!! OMG Thank you for explaining how the machine operates very incredible!

[@kiefershanks4172]

This was very interesting! Well explained! Thanks!

[@nealgray4071]

Best episode in a while, James has such passion for this stuff and is so good at explaining it all in accessible ways. This was the most interesting thing I've watched in months (says something about Netflix et al...) 😅

[@pascalbercker7487]

I was on the edge of my seat! Such drama - so well told! If he has kids I can imagine him telling them to tuck in - and get ready for a bedtime story!

[@davidpetzer5725]

Thank you , great explanation !!

[@happyhome41]

Fantastic ! I was alive, and captivated at the time - not realizing the sensational aspect at the time, so largely tuned it out. Great, now, finally, to understand.

[@tobyw9573]

Control of the components and materials of/in the reactor is key.

[@wewk584]

Excellent stuff !!

[@microburn]

Agree

[@Tgspartnership]

Fascinating explanation

[@youtux2]

49:08 Fascinating! Seems that one critical gap was the lack of actuator feedback: I show what the valve has been signalled to do, but not whether the actual state of the valve has changed accordingly; instead, a secondary effect of the status valve is used as a proxy for feedback signal. Adding to that, the proxy measurement is not suitably monitored by a simple threshold alert, leading to an "expected alarm" scenario where the state of the alarm (engaged/not engaged) requires additional context to be eventually evaluated as an actual alarm condition or not. Interestingly, this is exactly the type of problems that occur in software systems, where nfrastructure is designed and configured to automatically deal with transient problematic conditions and a real problem only occurs if the auto-remediation action doesn't complete within a "reasonable", time frame. The occurrence of false positives is the main issue.

[@johnstubbe3113]

Admiral Hyman, Rickover stated about the 3 mile island accident that if they had released the 3 mile island full report, nuclear power would have been killed forever

[@MackBrown27]

Currently a fairly standard method to ensure a critical valve is open or closed, is to use a valve position monitor or limit switches. This way it isn’t inferred from a command given to open or close the valve, but is measured and advised.

[@youtux2]

51:54 Woooow those question marks! The harm a well meaning assumption can do! In hindsight it would have been perhaps better for the computer to print the thermocouple measurements anyway, but with an added warning sign, such as a question mark, and leave it to the operator to trust the numbers or not

[@EricDMMiller]

Watching James swaying and rocking back and forth as he gets into the description gives me vertigo. 😵‍💫 It's kind of weird when he goes from sitting back to suddenly **FOREHEAD**

[@Modhuchosha]

Don't forget that Fukushima got hit by an earthquake+ tsunami.

[@kenvrinten3450]

Nowadays they have limit switces on critical valves to ensure that the valve is 100 %,open or closed. Also proximity switches will tell actual valve position.

[@tobyw9573]

Radioactive substances should not be under high pressure or subject to explosive chemical reactions in air or other reaction to avoid violent escape. Escape of radioactive material is the potential culprit..

[@tobyw9573]

A turbine is a rotating energy transfer device, a turban is a kind of mid-eastern hat. Why confuse us with one pronunciation with two different meanings?

[@chrisjohns38]

Are we forgetting about the status of the industry/owner RPV level indicator system safety status battle that was going on at that time?

[@RandoBox]

Any thoughts on San Onofre coming back online?

[@mykhailobortnik-api]

That's a good question!

[@microburn]

Mark Nelson has a lot of opinions on this one

[@RandoBox]

@@microburn Where?

[@paulwhelan8567]

It’s already half demolished.

[@ChaseNoStraighter]

Did you study anything that actually happened at TMI?

[@bryanwheat9101]

Proved that reactors with beefy secondary containment. The ge reactors are still pretty sketchy.

[@dodaexploda]

So a material that will heat up on it's own. Chris will know this. The little chemical "heater" packets that you put in your gloves in the winter. You gotta break something in the packet to get the two chemicals to mix. Then you get heat. It's like that, but instead of chemical exothermic heat, it's decay heat.

[@tgmct]

Decay heat is somewhat similar to coal burning in a boiler. Until the fuel is completely burned, it will produce heat.

[@doniehurley9396]

Seems like a realy close run thing if the pressure relief valve hadn't been closed at 2 1/2 hours would a half hour more have led to a total core melt and containment breach

[@kenvrinten3450]

I can imagine the HAZOP/HAZID for these plants would last weeks

[@FrankReif]

Boys. Just to let you know, most normal people would listen to this and not be reassured in the slightest. There's some real echo chamber vibes going on here. I'm generally pro nuclear btw. So I want you to do better.

[@andrewdonohue1853]

Chernobyl was something that never should have happened, and it is extremely unlikely to ever happen again. it was poorly built, the test was irresponsible and it had no real containment structure. people have had fear porn ever since, sadly. the RBMK had serious issues, and was also the product of communism.

[@pazsion]

🤣🤣🤣🤣 meanwhile people died fornthe next 3 years of horrible cancers in a 50 mile radius and 130 miles east more as the river and streams to the east were also contaminated. a majority of cancers were alongvthe water ways. the fish, some have never returned, they are gone now.

[@gomerromer7708]

Fifteen seconds in it seems pretty clear you do not know what the word "detonate" means. Bye Bye!

[@makotounagi434]

This event was done purposely