How to have fun with a nuclear reactor
Discussion
On todays theme of 'meddling scientists' (see LHC) I thought I'd share this excellent nuclear reactor related story someone emailed me a while back;
The setting is the Sequoyah Nuclear Plant in Chattanooga, TN. The date is about 1979 or 80 and we're starting that sucker up for the first time.
I was the shift test engineer, running the startup test program on the evening shift. Most testing is conducted from the control room. In order to get to the control room, a stroll across the turbine deck is necessary. This deck contains the huge (1200 MWe) turbines and a variety of support equipment. The floor is tiled and the 10 story tall walls are slightly tinted glass. A glorious sight when bathed in the afternoon sun.
As I was strolling toward the control room, I noticed an Aux. Operator standing near a device called a moisture separator/reheater. This device is a large heat exchanger, about 40 feet long and 20 feet in diameter. Its purpose is to reheat the steam exhausting from the high pressure turbine in order to dry it before being introducted into the low pressure turbines. On top of this device is a large safety relief valve with a tailpipe that extended almost 10 floors through the roof. When this valve opens, steam at about 900 psi exhausts to atmosphere through this ~36" tailpipe. The tailpipe is hung from spring hangers and simply floats on the exhaust flange of the safety valve which allows the pipe to move under thermal expansion.
Anyway, this operator was standing along side the reheater. In one hand was a walkie-talkie and in the other hand was a lanyard that ran to the manual trip lever on one of the safeties. This was not unusual, as the functionality of these critical valves is tested fairly often. Normally when the valve trips, there is some steam escaping around the valve, a loud shreik and a large steam cloud on the roof.
As I was almost to the control room, the operator got some activity on the handi-talkie and pulled the manual trip lanyard. The noise from the H-T had gotten my attention and I looked around just in time for the valve opening. FOOOMsssss!!!! The whole damn tailpipe jumped up about 6 inches in the air before settling back down.
Since this behavior was quite abnormal, I asked the operator what was going on. He pointed to the elevator and suggested I go to the roof to find out. I rode the elevator 5 floors and hoofed it up 5 flights of stairs and onto the roof. I noticed about 10 guys standing around near the tailpipe.
As I stepped out, I saw about 6 guys hoisting A 55 GALLON DRUM up and over the tailpipe. Whoosh. It hit bottom 10 floors below.
A message on the handi-talkie and BOOOMssss!!! That damn 55 gallon drum full of 600 pounds of water had been launched literally out of sight by 900 psi of steam.
It stayed out of sight a good 30 seconds before it came into view again, hurtling down over the Chickamauga lake. When it hit the lake, it looked like a depth charge going off.
I did a 180 degree twist and headed back down the stairs as fast as my little feet would carry me. As Shultz on Hogan's heros used to say, "I saw notsing.. I hear notsing.. I know notsing..". I did keep a piece of strip chart recording that showed the dip in steam pressure that documents the launch :-)
I heard a few days later that one of their ICBD (Inter County Ballistic Drums) had been caught by a gust of wind and had come down on a car in the parking lot, thus ending the era of the nuclear powered missile. The funny thing is, no one would ever admit to knowing how that drum ended up on the car, which ended up about 6 inches tall :-) So if anyone asks if America has ever launched a nuclear powered missile, you can answer truthful YES!
[BTW, I've waited 10 years to tell this story to ensure that my memory of the names of those involved has thoroughly faded just in case the nuke police were to get interested.]
The setting is the Sequoyah Nuclear Plant in Chattanooga, TN. The date is about 1979 or 80 and we're starting that sucker up for the first time.
I was the shift test engineer, running the startup test program on the evening shift. Most testing is conducted from the control room. In order to get to the control room, a stroll across the turbine deck is necessary. This deck contains the huge (1200 MWe) turbines and a variety of support equipment. The floor is tiled and the 10 story tall walls are slightly tinted glass. A glorious sight when bathed in the afternoon sun.
As I was strolling toward the control room, I noticed an Aux. Operator standing near a device called a moisture separator/reheater. This device is a large heat exchanger, about 40 feet long and 20 feet in diameter. Its purpose is to reheat the steam exhausting from the high pressure turbine in order to dry it before being introducted into the low pressure turbines. On top of this device is a large safety relief valve with a tailpipe that extended almost 10 floors through the roof. When this valve opens, steam at about 900 psi exhausts to atmosphere through this ~36" tailpipe. The tailpipe is hung from spring hangers and simply floats on the exhaust flange of the safety valve which allows the pipe to move under thermal expansion.
Anyway, this operator was standing along side the reheater. In one hand was a walkie-talkie and in the other hand was a lanyard that ran to the manual trip lever on one of the safeties. This was not unusual, as the functionality of these critical valves is tested fairly often. Normally when the valve trips, there is some steam escaping around the valve, a loud shreik and a large steam cloud on the roof.
As I was almost to the control room, the operator got some activity on the handi-talkie and pulled the manual trip lanyard. The noise from the H-T had gotten my attention and I looked around just in time for the valve opening. FOOOMsssss!!!! The whole damn tailpipe jumped up about 6 inches in the air before settling back down.
Since this behavior was quite abnormal, I asked the operator what was going on. He pointed to the elevator and suggested I go to the roof to find out. I rode the elevator 5 floors and hoofed it up 5 flights of stairs and onto the roof. I noticed about 10 guys standing around near the tailpipe.
As I stepped out, I saw about 6 guys hoisting A 55 GALLON DRUM up and over the tailpipe. Whoosh. It hit bottom 10 floors below.
A message on the handi-talkie and BOOOMssss!!! That damn 55 gallon drum full of 600 pounds of water had been launched literally out of sight by 900 psi of steam.
It stayed out of sight a good 30 seconds before it came into view again, hurtling down over the Chickamauga lake. When it hit the lake, it looked like a depth charge going off.
I did a 180 degree twist and headed back down the stairs as fast as my little feet would carry me. As Shultz on Hogan's heros used to say, "I saw notsing.. I hear notsing.. I know notsing..". I did keep a piece of strip chart recording that showed the dip in steam pressure that documents the launch :-)
I heard a few days later that one of their ICBD (Inter County Ballistic Drums) had been caught by a gust of wind and had come down on a car in the parking lot, thus ending the era of the nuclear powered missile. The funny thing is, no one would ever admit to knowing how that drum ended up on the car, which ended up about 6 inches tall :-) So if anyone asks if America has ever launched a nuclear powered missile, you can answer truthful YES!
[BTW, I've waited 10 years to tell this story to ensure that my memory of the names of those involved has thoroughly faded just in case the nuke police were to get interested.]
The scary part of this story is that I am not the slightest bit surprised. However things have changed sooo much over the last 30 odd years 
I remeber all sorts of great stuff we got up to at work in the 80s and early 90's that then were seen as high sprits and now woudl result in summary dismisal.
No fun at all now!
Thanks for the story tho'
Spunagain
I remeber all sorts of great stuff we got up to at work in the 80s and early 90's that then were seen as high sprits and now woudl result in summary dismisal.
No fun at all now!
Thanks for the story tho'
Spunagain
Good story.
Here's a darker one (WARNING it's bit gruesome), from the early days - the SL1 incident.
A small, 3MW experimental BWR called SL-1 (Stationary Low-Power Plant No. 1) in Idaho was destroyed on January 3, 1961, when a control rod was removed manually.
At 9:01pm, alarms sounded at the fire stations and security headquarters of the U.S. National Reactor Testing Station where the reactor was located. Investigation found two operators dead (third died later), and detected high radiation levels in the building.
A careful examination of the remains of the core and the vessel concluded that 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, causing the plate-type fuel to melt. The molten fuel interacted with the water in the vessel, producing an explosive formation of steam that caused the water above the core to rise with such force that when it hit the lid of the pressure vessel, the vessel itself rose 3 meters in the air before dropping back down.
The SL-1 accident was the first fatal nuclear accident in the United States. The men killed in the incident were two Army Specialists, John Byrnes, age 25 and Richard McKinley, age 22, and Richard Legg, a 25 year old Navy Electricians Mate. The three men were killed as they moved fuel rods in a "routine" preparation for the reactor start-up. One technician was blown to the ceiling of the containment dome and impaled on a control rod. His body remained there until it was taken down six days later. The men were so heavily exposed to radiation that their hands had to be buried separately with other radioactive waste, and their bodies were interred in lead coffins.
ETA http://en.wikipedia.org/wiki/Louis_Slotin For a Nuclear Darwin award.
Here's a darker one (WARNING it's bit gruesome), from the early days - the SL1 incident.
A small, 3MW experimental BWR called SL-1 (Stationary Low-Power Plant No. 1) in Idaho was destroyed on January 3, 1961, when a control rod was removed manually.
At 9:01pm, alarms sounded at the fire stations and security headquarters of the U.S. National Reactor Testing Station where the reactor was located. Investigation found two operators dead (third died later), and detected high radiation levels in the building.
A careful examination of the remains of the core and the vessel concluded that 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, causing the plate-type fuel to melt. The molten fuel interacted with the water in the vessel, producing an explosive formation of steam that caused the water above the core to rise with such force that when it hit the lid of the pressure vessel, the vessel itself rose 3 meters in the air before dropping back down.
The SL-1 accident was the first fatal nuclear accident in the United States. The men killed in the incident were two Army Specialists, John Byrnes, age 25 and Richard McKinley, age 22, and Richard Legg, a 25 year old Navy Electricians Mate. The three men were killed as they moved fuel rods in a "routine" preparation for the reactor start-up. One technician was blown to the ceiling of the containment dome and impaled on a control rod. His body remained there until it was taken down six days later. The men were so heavily exposed to radiation that their hands had to be buried separately with other radioactive waste, and their bodies were interred in lead coffins.
ETA http://en.wikipedia.org/wiki/Louis_Slotin For a Nuclear Darwin award.
Edited by rhinochopig on Wednesday 10th September 14:02
SL-1 wasn’t the first fatal nuclear accident –you link to Slotins wikipedia entry in the very same post, which has a reference to Harry Daghlian. He accidentally assembled a critical plutonium assembly in 1945. I always think that must have been a thoroughly unpleasant way to go; as soon as you see the flash and feel the heatwave you know you’re f
ked but it takes a few days at least before you’re actually dead. As you say, the way Slotin irradiated himself wasn’t exactly smart and may be a bit of a Darwin nomination. I’ve always had a bit of sympathy though – working in the lab on something interesting it’s always tempting to speed things up by cutting down on health and safety. Our safety officer nearly shat a brick when he saw the ‘30,000 volt rated cable’ I had improvised from a 3000V rated cable, a length of thick rubber hose and some gaffer tape. As people have said H+S would have your balls for trying the oil drum stunt these days. Even back in 1980 I would imagine that they would have frowned on it…
That SL-1 accident must have been scary. I’ve seen a video of an experimental reactor being deliberately forced to go super-prompt-critical (way out in the desert!) and the gallons of coolant flashes to steam basically instantly.
ked but it takes a few days at least before you’re actually dead. As you say, the way Slotin irradiated himself wasn’t exactly smart and may be a bit of a Darwin nomination. I’ve always had a bit of sympathy though – working in the lab on something interesting it’s always tempting to speed things up by cutting down on health and safety. Our safety officer nearly shat a brick when he saw the ‘30,000 volt rated cable’ I had improvised from a 3000V rated cable, a length of thick rubber hose and some gaffer tape. As people have said H+S would have your balls for trying the oil drum stunt these days. Even back in 1980 I would imagine that they would have frowned on it…That SL-1 accident must have been scary. I’ve seen a video of an experimental reactor being deliberately forced to go super-prompt-critical (way out in the desert!) and the gallons of coolant flashes to steam basically instantly.
Spunagain said:
The scary part of this story is that I am not the slightest bit surprised. However things have changed sooo much over the last 30 odd years
I remeber all sorts of great stuff we got up to at work in the 80s and early 90's that then were seen as high sprits and now woudl result in summary dismisal.
No fun at all now!
Thanks for the story tho'
Spunagain
We had some apprentices that got a little telling off, this was before my time so in the 70s.... they had a dartboard at one end of a long corridor just off the machine shop, the corridor had a number of offices off of it. They had the really bright idea of attaching some metal tubing to the airline and firing lengths of welding rod at the dartboard - can you imagine the paperwork explaining why the tealady ended up with a foot of welding rod in her jugs? I remeber all sorts of great stuff we got up to at work in the 80s and early 90's that then were seen as high sprits and now woudl result in summary dismisal.
No fun at all now!
Thanks for the story tho'
Spunagain
King Herald said:
And people wonder why things like Chernobyl happen with rocket scientists like this in the game.
Lighten up, it was a funny story and I thought people would like it. People playing around with the steam outlet from a turbine is not going to lead to a Chernobyl like accident. Chernobyl happened because it was a very poor reactor design and, due to the operators not really understanding it, it was being operated in a particularly dangerous manner. phumy said:
All of the reactors today are designed to have a negative reativity coefficient, so they shut their selves down automatically, or at least should, in theory.
Yep. They're all set up to have negative feedback so you don't get a run away reaction. You can still get a core meltdown because of decay heat but, unlike the RBMK, they have a containment building to keep all the nasty stuff from being spread around.
@ original story, that is fking brilliant.I do like the idea of totally mad nuclear powered stuff.
http://pigeonsnest.co.uk/stuff/nuclear-water-pump....
Nuclear Saftey Engineer: Now, relax, Homer. This is a simulation of your work station and we're going to simulate a power surge in Sector 8.
Homer: What the hell are you talking about?
(After Homer causes a nuclear meltdown in a simulator)
Nuclear Safety Engineer: I don't understand it! There wasn't any nuclear material in that van!
Homer: What the hell are you talking about?
(After Homer causes a nuclear meltdown in a simulator)
Nuclear Safety Engineer: I don't understand it! There wasn't any nuclear material in that van!
hairykrishna said:
King Herald said:
And people wonder why things like Chernobyl happen with rocket scientists like this in the game.
Lighten up, it was a funny story and I thought people would like it. People playing around with the steam outlet from a turbine is not going to lead to a Chernobyl like accident. Chernobyl happened because it was a very poor reactor design and, due to the operators not really understanding it, it was being operated in a particularly dangerous manner. 
I was 'mocking seriousness'. Never mind....
Mildly O/T, but does anyone know the story a Physics teacher once told me about an MRI scanner that was sited a little too close to a railway. It was powered up in the evening and the following day was conspicuous in its absence (along with a rather large hole in the wall). It was found quite a few miles away where it had finally detached itself from a freight train.
Similarly there was the tale of a power station turbine that had complete main shaft bearing failure, locked up and launch the whole turbine through the roof and a very, very long way away.
Similarly there was the tale of a power station turbine that had complete main shaft bearing failure, locked up and launch the whole turbine through the roof and a very, very long way away.
King Herald said:
hairykrishna said:
King Herald said:
And people wonder why things like Chernobyl happen with rocket scientists like this in the game.
Lighten up, it was a funny story and I thought people would like it. People playing around with the steam outlet from a turbine is not going to lead to a Chernobyl like accident. Chernobyl happened because it was a very poor reactor design and, due to the operators not really understanding it, it was being operated in a particularly dangerous manner. I was 'mocking seriousness'. Never mind....
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