Posted on 03/15/2012 1:16:25 PM PDT by Mad Dawgg
I am working on a story and in the story people don't show up for work anywhere including the power plants (electrical generation).
So what happens? For instance will a Nuke plant shut down safely if no one shows up ever again or will the plant become unstable after a time with no human supervision and it would go into meltdown and/or releases some form of nuclear exhaust? If so what are we talking here? China Syndrome or something like the what happened in Japan after the quake?
A coal fired plant or a gas fired plant I would surmise would just cease to function once the fuel ran out. Of course I understand once you get a couple of plants offline then the grid would start reacting and I guess it would cause a blackout like we had a few years back.
But what would happen at the plants themselves with no one there to react to a demand for more power? Would such cause the plants still running to try and take up the slack? If so when they tried to keep up could it cause them to work too hard and cause explosions?
I figure Hydro plants would just keep on going till the turbines burnt up unless there are automatic relays that shuts them down if the load becomes to heavy...
How long could the grid stay active without human supervision? Are we talking hours or days or weeks?
This is research for a story so any help is greatly appreciated, first hand knowledge or links on the web or good books and movies are all appreciated!
Coal fired plants pulverize the coal to a powder about as fine as talcum powder. The powdered coal is injected into the boiler with an air blast which if you could see inside looks very much like the flame from either oil or gas. The point being there is no serious amount of unburned fuel stored in the boiler. The plant has large piles of coal on site which require someone driving a crawler tractor to move coal from the storage pile to a conveyor which loads a silo. The silo holds a supply of coal to feed the grinding mills. When the silo empties the plant shuts down.
I would guess that the working storage would be enough for an hour or two at full load. Oil fired plants might last a bit longer because the fuel comes in ready to use. Gas fired plants store no fuel at all on site and would shut down as soon as pressure dropped in the pipeline.
Last year the Discovery channel did a series on the world without people. They predicted that hydroelectric plants would continue running for (hundreds of??) years. (the power grid protects itself by isolating areas that have lost power so plants still running will not experience an overload) The failure mode was brought about by clogging of small intake pipes which bring in river water to cool the oil used to lubricate the turbine bearings. As the oil heats it trips a shut down of that unit. Eventually all the turbine generators go off line, the water level behind the dam rises to the overflow and the river continues on it's merry way. Earth dams would not last much longer but the big concrete dams may last for thousands of years before an earthquake finally destroys them.
Regards,
GtG
I was just telling my daughter about this kind of stuff in telling her that one doesn’t prepare because of Zombies. I asked her how long do you think the electrical generation plants, water plants, sewage plants, etc. will keep running if most of the people don’t show up for work.
And all it would take is a deadly flu strain to do it. Between sick folks not showing up, folks staying home to tend to their sick loved ones, and healthy folks staying home so as not to get infected - it is a likely event at some point (again) in our future. Oh - and add in the mistakes that would be made by running the thing short-handed, or the upper-level management trying to do the operator’s jobs.
This is essentially the rapture scenario if you assume all workers are saved. This is written for pressurized water reactors. boiling water reactors fail quicker. I was going to wait till Fellow Traveler had a longer reply, but here goes:
Time Zero - People Disappear.
Loads begin to drop (manually controlled electrical equipment shuts down.
Hour One -
Loading continues to diminish somewhat, then spike as coal powered plants shut down (to the extent than automatic network switching is in place) for those areas requiring manual switching, they go dark, load drops
Hour Two - Rapid changes in system load take some units offline due to turbine overspeed trips. Some plants shut down when loss of all offsite power is detected. Diesel generators on site startup to power emergency core cooling systems. Some plants have gravity-asssited natural circulation ECCS and will shutdown but stay metallurgically intact for days to weeks.
Hours 3-6 Load cycling continues somewhat , load stabilizes below 50% as infrastructure damaged by vehicle collisions burns pit and is isolated. Plants with running functional diesel generators to make up for single lost external supplies may continue to operate. Most plants shut down when loss of all offsite power is detected. Others (e.g. Fukushima) shutdown when the supported subsystems fail. Low level releases of radioactivity are possible.
Hours 6-12 Many plants stay online. Those with offsite power available having functioning automatic feedwater and cooling water systems stay up, but loss of offsite power for ECCS and failures in water subsystems result in many more shutdowns.
Hours 12-24 Out of more than 100 nuclear power plants in US, perhaps a dozen are still on line. Those online and offline with functional offsite power and/or diesel generators have good cooling for reactor and spent fuel storage (SFS).
Day Two
All units are offline, from either loss of offsite power, or various cooling water sensor trips that would have been prevented by human activity (switch intakes, pumps, etc). Units without good offsite power are depending on the diesel generators to keep SFS and core cool.
Day Three on...
When diesel fuel runs out, they join unpowered sites in core temperature increases, fuel pool temperature increases. At about 2012 degrees Fahrenheit, zirconium in the fuel cladding & rods changes from monoclinic to tetragonal(becoming Cubic Zirconia!)and fuel rods can crack. Rods that melt tend to fall away from each other (core slump) not toward a more concentrated grouping (sorry, no China Syndrome)a result of inadvertently good design feature by engineers pointing error in the conservative direction) discovered by analyzing the TMI core. Slight releases of radioactivity to the environment, most is contained.
First Decade -
The sites heat up for a few years, perhaps the first decade, then begin to cooldown over time. Site radiation levels are stable.
First Century -
Sites are essentially overgrown and buried by blowing sand dirt and debris. Sute radiation levels are dropping slowly. The snow always melts first here each year though...
Please excuse some typos. new computer, weird keyboard.
Last one to leave, please turn off the lights.
Combined cycle(Gas turbine with the exhaust being fed to a boiler to generate steam which is then used in another turbine), Coal and Nuclear all share the same problems. Balance of plant which includes everything not related to the Boiler/reactor and turbine generator equipment is not automated very well. From what I have seen this is the most common area requiring operator intervention in the day to day operation of a power plant. This can be everything from water treatment plants , Evaporative coolers, fuel handling(Several people mentioned that coal plants are fairly operator intensive and they are right about that) and other systems. Any and all of these can have problems or need human intervention to operate correctly on a day to day basis.
Nuclear presents it's own special problems. Like all units they are designed to react automatically to dangerous situation where the response time needs to be in seconds or fractions of a second. The problme comes later the units will require some sort of operator intervention to complete safe shut down. Motors need to be started and valves operated, that sort of thing.
Trying to restart units that have been improperly shut down could be very difficult in most cases. First off station batteries would have to be recharged. Power plants use 125V DC power to run their internal relays, meters, control systems and switch gear. Without that power nothing works. If a turbine rotor is stopped in one position while it is still hot you can get a situation called rotor bow. The residual heat in the turbine collects in the top of the casing and the rotor will grow towards this heat. This causes the rotor to become unbalanced. It takes a good long while to spin out a rotor bow. A host of other issues could plauge any startup attempt. Contaminated boiler water. Plugged injectors in boilers. Tube breaks in boilers due to water slugging. I could go on and on.
One other issue exists and that is the varying system load throughout the day. Generators are all run in synch with each other. System load is balanced by dispatchers calling up the plants and asking them to raise or lower power and voltage( Really Var) output. This system is not automated to the best of my knowledge. Unbalanced systems will cause the frequency of the system to speed up or slow down. All generators have a protective relay called Volts per Hertz. Essentially this realy looks at the voltage output of the genertor and divides that by the frequency. This matters because electrical insultion has the ability to work better at higher frequency than lower frequency. For instance GE sells generators rated at 13.8kv and 60 Hz. They sell the same generator over seas and it is rated at 12.5kV and 50 Hz. Any system underfrequency will start tripping out units at about 58.5 Hz. That is a little less than 3% variance from the current load point of the system. Likewise the all generators are equipped with overspeed devices. Usually anywhere between 108 to 111 percent of rated frequncy will cause them to trip. Feel free to emial me if you have any other questions.
There is a documentary on cable a few years ago, I think it was called After People, or something like that. The premise was that suddenly the earth was not populated by humans.
Anyway, I think the generators would be fine and the electricity would be running for months.
This special may be available online, or at your library. Check it out.
Sre
There is a documentary on cable a few years ago, I think it was called After People, or something like that. The premise was that suddenly the earth was not populated by humans.
Anyway, I think the generators would be fine and the electricity would be running for months.
This special may be available online, or at your library. Check it out.
Sre
I work at a wastewater plant and can guarantee you that $h*t will hit the fan(spinning or not) if people don’t show up. Manhole covers will be popping off downtown as remnants from the bowels of civilization flow through the streets.
In answer to my question about what happens if the power plant employees just decide that entitlements pay more than work:
http://www.freerepublic.com/focus/f-news/2860231/posts
Obama signed a new EO to fix that. Simple answer is we become Nation Defense Resources. Slaves.
Oh my, that is just spooky. I been thinking about this story for a while and working out the details thinking the Gub'ment would be in chaos because no prior planning and no way legally to force folks to do these needed things and this crap magically appears.
Wow, this makes me reassess my story plot line and more importantly my SHTF preparations.
Directive 10-289. The worst criticism you can make of Atlas Shrugged is that the left would use it as an instruction manual.
Yes, but - when the grid goes whiggy, they shut down, and are not coming back.
Good timeline, BTW.
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