America's forgotten nuclear accident
April 3, 2006 4:44 AM   Subscribe

The SL-1 Reactor, part of the short-lived Army nuclear power program, became America's only fatal nuclear accident when it exploded in its warehouse, killing three technicians.
posted by Ridx (20 comments total) 1 user marked this as a favorite
my first post, hope ya'll like it
posted by Ridx at 4:45 AM on April 3, 2006

Other than one comment, good post. Two to wikipeida is sort of weak, but you've got another.

We've had many more fatal nuclear accidents, esp. in the early days. Louis Slotin and Harry Daghlian leap to mind -- both dying in supercriticality accidents1.

You could argue that the Japanese fishing boat crewman who died after being exposed to the fallot from Castle Bravo is an accidental radiation casualty, as well -- Castle Bravo ended up yielding about three times more energy than expect, and the fast neutron pulse caused the U238 tamper to fission, dramatically increasing the yeild and the fallout.

[1] Supercritical, but not prompt supercritical. You would have noticed that. ;)
posted by eriko at 5:15 AM on April 3, 2006

I've heard about this before. The interesting part of the story, hidden somewhere in that Wikipedia article, is that one of the technicians completely removed the control rod - probably with full knowledge of what would happen - and no one knows why.
posted by cillit bang at 5:37 AM on April 3, 2006

What eriko said: good post, weak links.

Crane mounted sling used to retreive the body of the SL-1 operator from the ceiling of the building. The body was located in a radiation field measuring 1000 R/hr

Our new RS-500 nuclear radiation detector and meter measures radioactivity from the lowest background radiation levels up to 999 mR/hr (10,000.00 ┬ÁSv/h) (a radiation level that can be reached only in a major nucelar accident or after a nuclear terrorism attack or the explosion of a nuclear weapon). This is 20 times more than ordinary radiation detection devices...

and 1000 times less than what these men were exposed to.
posted by three blind mice at 5:47 AM on April 3, 2006

It may not have been full knowledge, it could have been carelssness and complacency. A technician needed to withdraw the main control rod manually to get it attached to the autmated controls. If that sucker bound a bit, it'd be simple enough to get up on top, tug, tug, tug at the rod with a good bit of force, and have just enough time to think "Oh, sh..." when the rod suddenly slipped free and came out a lot more than expected.

Bad design, compacent operators, a feeling of "Hey, it's safe enough, otherwise they wouldn't have us doing this manually" - it's a recipe for accidents.
posted by JB71 at 5:54 AM on April 3, 2006

More on the SL-1 is here, here, and here. Reading detailed reports on accidents like this is really interesting. It is good to have some insight into how accidents happen.
posted by TedW at 6:26 AM on April 3, 2006

the control rod was manually withdrawn by about 50 centimeters (40 centimeters would have been enough to make the reactor critical), largely increasing the reactivity. The resulting power surge caused the reactor power to reach 20,000MW in about .01 seconds

.01 second from stable to explosive. . . Ouch.
posted by mk1gti at 7:12 AM on April 3, 2006

The freakiest part of this accident is that the responders found the body of one of the technicians impaled on a control rod on the ceiling of the reactor room.
posted by Skorgu at 7:25 AM on April 3, 2006

eriko- Ah, I'm embarassed. I guess I meant "nuclear accidents involving the explosion of a reactor vessel".

JB71- I agree, the "stuck rod" idea seems to be the most plausible cause. I can think of better ways to commit suicide.

After SL-1 it became a standard criterion of reactor design that it could not go prompt critical from one fully withdrawn rod.
posted by Ridx at 8:11 AM on April 3, 2006

If you've ever tried to fix your car at 2AM, you know things get a little fuzzier around that time of the night...

Another lesson learned: Don't work on nuclear reactors when your body and brain are falling asleep, unless you absolutely have to.
posted by anthill at 8:45 AM on April 3, 2006

There was a documentary on this on discovery or something last year. Really interesting.

Yeah, he was trying to free a stuck rod, and it came free too far, too fast. The heat turned all the water to steam sending the entire reactor into the ceiling (that's how he was impaled.)
posted by rubin at 8:45 AM on April 3, 2006

eh, sorta- the reactor's pressure vessel blew apart (this is a steam explosion, the same thing happened to the chernobyl reactor before the graphite melted) and the control rod was shot through the cieling because it was the only penetration into the vessel.

anthill- apparently you've never served on a submarine ;)
posted by Ridx at 8:56 AM on April 3, 2006

Ah, SL-1. Every Navy Nuke's favorite story about why we can't let the Army have nice things. Just kidding though, as one of the operators was Navy.

eriko - I think the difference in fatal accidents is that this one was operational, not a test or experiment. It does bring to mind how either brave/stupid/unlucky those early guys like Slotin were.

anthill - a nuclear plant is something most people are comfortable with just turning the lights off and locking the door when you go home (even a little 3MW like SL-1), therefore there's usually a shiftwork rotation so someone's always around. The mid watch is actually a good time to get some stuff done, as not as busy.

And Ridx - Welcome aboard...hehe.
posted by jawbreaker at 10:31 AM on April 3, 2006

Ridix -

The guys doing this were 22 and 25, according to the article.

There's three general classes of advisories in military tech manuals. (I'm simplifying greatly here, of course...)

There's "Note:" which means be careful about something - like "Note: Don't use a breaker bar to remove a frozen bolt, you might snap it off and the bolt will need to be drilled out."

There's "Caution:" which means potential for serious damage to equipment - like "Caution: do not attempt to replace ANW-344 module without removing power to entire ANW-43 system and locking out all circuit breakers, or the magic smoke will leak out rendering the entire system unusable."

And then there's "Warning:" which tries to keep people from doing things which can get them hurt or killed as in "Warning: Do not attempt to pass within 5 feet of jet intake while engine is idling, or 15 feet when engine is at full power to avoid being ingested, minced, cooked and spat out the back end as bits of BBQ'd long pork - and incidentally damaging the engine but we guarantee you won't be worried about it."

Usually warnings come from feedback from the military to the manufacturer when some airman or grunt or squid does something noteworthy, messy and somewhat unforseen. The manufacturer issues an update, the military gets it and prints off a few thousand copies, and it's sent out to central tech order libraries and units who use that particular piece of equipment to remove and replace the appropriate pages in their manuals. If it's a really hot problem it'll be spread out via email until a safety supplement can be issued, which will be in effect until the next manual revision.

In this case, I think that there were three contributing factors to the whole event.

First - this was essentially a prototype, and not all the mistakes had been made yet that would normally generate the safety warnings in the manuals.

Second - the reaction time from 'lnert lump o' stuff' to critical is/was much shorter than ANYTHING the human nervous system could possibly deal with.

Third - 22/25 years old, and you're left in charge of a nuclear reactor. This means you're hot shit, you've likely memorized the manual and you know what you're doing (or else they wouldn't leave you with it) and if it's not in the manual, it's not important.

So - Hand connect the control rod? Sure! Why not?

And that the rod impaled one of the guys - well, you ever try to pull a piece of pipe or rebar out of the ground? You straddle it, grab it, then lift with your legs instead of your back...

And the thing came free a foot or so. (What was probably the last thing that went through that guy's mind? The control rod...)

Re better ways to commit suicide - less messy, certainly. Less expensive to clean up, definitely. But on the other hand, this IS a singularly unique way of offing yourself.
posted by JB71 at 10:36 AM on April 3, 2006 [1 favorite]

I hate it when they do this..
posted by JB71 at 11:35 AM on April 3, 2006

Um... disregard.... (terribly embarrased...)
posted by JB71 at 11:38 AM on April 3, 2006

A few months later, one of the guys reconstituted himself from the air, and was heneforth known as 'Dr. Manhattan.'
posted by bingo at 2:20 PM on April 3, 2006

Tickling the dragon's tail: the first radiation death in the United States occurred in August 1945 in Los Alamos, New Mexico during the Manhattan Project.

During a criticality test accident, Canadian physicist Louis Slotin (Wikipedia) moved a plutonium hemisphere with his bare hands and received a fatal dose of more than 2000 rem (2,000,000 millirem.)
posted by cenoxo at 11:23 PM on April 3, 2006

From TedW's first link -- whoa. New Year's Eve party. Guy goes back to his experiment, causes accident, dies. Guy walking past gets severely burned. Memories of Doc Manhattan.
posted by dhartung at 1:01 AM on April 4, 2006

Great links, thank you for shedding light on the subject. The level of detail in these accidents are... amazing. I personally thought the link by cenoxo regarding Louis Slotin to be especially cutting:

"On May 21, the screwdriver slipped, the two hemispheres touched and created a burst of hard radiation. The "blue glow" of air ionization was observed and a "heat wave" was felt by the scientists in the room. Slotin's instant reaction was to separate the masses by hand, by flipping the upper one to the floor. While he succeeded in ending the critical reaction and shielding seven other observers in the room, he exposed himself to a lethal dose (around 2100 rems, or 21 sv) of neutron and gamma radiation, in history's second criticality accident. In addition to the blue glow and heat, Slotin experienced a sour taste in his mouth and an intense burning sensation in his left hand."
posted by Dean Keaton at 3:18 AM on April 4, 2006

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