1958 Y12 Oak Ridge nuclear criticality accident

[R_Bert]

The big one.

40 years later, I would work in the same area.


http://knoxblogs.com/atomiccity/2014/06/14/nuclear-survivor-bill-clark-recalls-1958-criticality-accident-life-since/#more-28584

[Guest Lester Weevils]

Thanks, never heard that story before.

 

The article says the criticality lasted 20 minutes or something. Do you know how they sqelched it? Something like pump part of the HEU out of the barrel?

 

Or did it just melt out of the barrel and then disperse on the floor or something?

[vontar]

very interesting read.

[leroy]

Interestin stuff... Thanks for posting it...

 

leroy

[R_Bert]

Thanks, never heard that story before.

The article says the criticality lasted 20 minutes or something. Do you know how they sqelched it? Something like pump part of the HEU out of the barrel?

Or did it just melt out of the barrel and then disperse on the floor or something?

It burped enough out on to the SS floor to go sub-critical. (In simple terms, fat cylinder is bad, shallow with high surface area good - allows neutrons to escape the solution, shutting off chain-reaction).

Safe geometry for HEU solution is nominally 5". That drum was never intended to cactch HEU, but rather rinse water from the tank (water based- uranyl nitrate).

As you might guess, safety processes and procedures tightened up after the event. Edited June 15, 2014 by R_Bert

[R_Bert]

As the storage tank continued to empty into the drum, it would again go critical, some 5 or 6 times I think.

It was not shut down. It went out on its own.

[R_Bert]

http://en.m.wikipedia.org/wiki/Tokaimura_nuclear_accident

Here is a very similar incident in Japan a few years ago . Killed two.

[analog_kidd]

http://en.wikipedia.org/wiki/1961_Goldsboro_B-52_crash

 

Here's a story I just heard about for the first time, about a nuke carrying bomber that crashed in North Carolina in 1961. The bomb was one safety measure away from turning that part of the state into a wasteland. All other arming mechanisms had activated.

[Guest Lester Weevils]

It burped enough out on to the SS floor to go sub-critical. (In simple terms, fat cylinder is bad, shallow with high surface area good - allows neutrons to escape the solution, shutting off chain-reaction).

Safe geometry for HEU solution is nominally 5". That drum was never intended to cactch HEU, but rather rinse water from the tank (water based- uranyl nitrate).

As you might guess, safety processes and procedures tightened up after the event.

 

Wow. I can't even imagine how nasty and dangerous the cleanup operation must have been!

[R_Bert]

It burped enough out on to the SS floor to go sub-critical. (In simple terms, fat cylinder is bad, shallow with high surface area good - allows neutrons to escape the solution, shutting off chain-reaction).

Safe geometry for HEU solution is nominally 5". That drum was never intended to cactch HEU, but rather rinse water from the tank (water based- uranyl nitrate).

As you might guess, safety processes and procedures tightened up after the event.

 

 

Wow. I can't even imagine how nasty and dangerous the cleanup operation must have been!

Well, it is serious, but the facilities are designed to facilitate recovery from contamination events. They are uranium processing facilities to begin with, and are not concerned too much with fixed/non-removable contamination.

 

The cleanup would have consisted of mops, towel-wipes, percoline, standard industrial cleaners.  The radiation hazards would not have been significantly different (this was a series of very short lived events as opposed to reactor operations and spent fuel rods for example - so miniscule fission products in the grand scheme of things).  The major exposure was instantaneous in the form of heat and neutrons, and prompt gammas (burns, internal and external from brief but VERY intense exposure). What it left behind was mostly uranyl nitrate solution in the floor (they dealt with spills all the time)

 

Uranium is not a external radiation hazard as much as a inhalation hazard; alpha emission deposits energy to cells in the lungs, and can cause cancer (think polonium from cigarettes). So as long as you do not breath in or eat loose uranium particulate, one is relatively safe.

 

There is of course significant anti-contamination protocols and procedures for conduct of operations, dress, materials storage, etc. including boundary control stations and dress-outs.

 

BTW, here is a 1961 report on the incident - https://www.osti.gov/opennet/servlets/purl/16291912-2PMGg0/16291912.pdf

 

Dad (who worked adjacent to C-1 wing and was there that day) says that the building (9212) was back in operation the same day, and that he seems to recall that the C-1 wing was back up and running in about a week.

 

Nowadays, if that happened, the place would be shut down for years.

Edited June 16, 2014 by R_Bert

[fourbyland]

Interesting. I remember my grandfather telling us about this. He worked there from the late 40's-70's.

[peejman]

Interesting stuff.  Thanks.