Posted on 03/11/2011 5:40:48 PM PST by winoneforthegipper
Attention is focused on the Fukushima Daiichi and Daini nuclear power plants as Japan struggles to cope in the aftermath of its worst earthquake in recorded history.
Three of Fukushima Daiichi's six reactors were in operation when yesterday's quake hit, at which point they shut down automatically and commenced removal of residual heat with the help of emergency diesel generators. However, these suddenly stopped about an hour later for reasons as yet unknown.
(Excerpt) Read more at world-nuclear-news.org ...
I Marquette Mich a few years back they had a dam break above a coal fired plant. The water took out sub stations, fuel tanks for EM Generator sets and heavy equipment, EVERYTHING. It shut that plant down for weeks. Last I knew, they still havent found a couple of those transformers. They went into Lake Superior and simply disappeared.
The Unit 3 reactor is using MOX fuel - it needs to get stabilized first.
“Sounds like bad maintenance on the genset”
Maybe tsunami salt water.
People really underestimate what can pick up and move when a wall of water comes a-callin’.
In Rexburg, ID, they had a earthen dam let loose back in 1976 (the Teton Dam).
When the dam operator saw that there were leaks, they tried to patch the leaks with two Cat D-8’s pushing fill into the gap.
They still have not found one of the D-8’s, despite looking for it down the riverbed, all these years later. The two D-8’s were rolled end-over-end according to eyewitnesses as the dam burst - like they were little toys.
That’s 40 tons of steel, just gone. And it isn’t as tho there’s a lake or other deep body of water downstream, either. The stream that filled the dam isn’t a huge flow. They found one of the D-8’s sticking out of the mud downstream, but the other one just disappeared.
I believe this is one of the older reactors, constructed circa 1971. Normally upon shit down, the electric pumps would operate off shore power, then an auxiliary power of Gensets are available, and then the battery standby power.
I suspect they may also have had a turbine in there somewhere, and the first news I heard was of fire in the turbine room.
I don’t know what seismic activity was experienced at the power station prior to the event, but it might have contributed to any or all of these systems having slight maladjustments. They probably were designed for a given seismic loading, but not necessarily every degree of freedom and harmonic which might be experienced. With earthquakes and Acts of God, there’s only so much one can practically design to accommodate.
I believe the batteries probably only have 4-12 hr life, so they are probably balancing critical cooling until power is restored from one of several sources.
Those Gen-sets are most likely 24MW or 6000KW sets..or similar.
So..I would guess they are about 3-4500HP and heavy fuel type engines. What make? I dont know, but I do know that the Japanese make some pretty good engines.
So to compare..it would be about like a train locomotive engine with a generator about the same size. About a 12 to 14 inch bore with top rated RPM at about 250 to 400 RPM, depending on the gearing on the business end.
I worked on these types of engines in my much younger days after I got out of diesel engineering school.
“They should have had planned for these contingencies.”
I actually have been involved in safety issues with nukes (mostly by doing IEEE-323 standards compliance and some FMEA and FMECA systems work).
Believe me, they try to think of every contingency and every combination.
All piping and containment and structure is designed to withstand the worst-case earthquake for the area, using verified finite-element computer structural models, but nothing says a beyond-design quake won’t happen eventually. It’s like living in a 99-year floodplain and getting flooded twice in 25 years. Note, though, that for the most part this plant held together for the quake itself. Looks like some other combination caused a problem with the emergency power plant.
One of the US plants I worked on considered a SCRAM, loss of offsite power, losing one genset, two valve failures, and an overturned chlorine truck delivering chlorine gas, all at once, plus instrumentation problems in a shorthanded control room. “So how do we design to mitigate that?”
Things go wrong, sometimes. You and I both wish that bad stuff wouldn’t happen, but this is reality.
These pumps probably pull 1.5 megawatts each and are half the size of a house. The emergency gens to run one pump would be a decent sized power plant.
I worked on an emergency pump power transfer switch that was 460 VAC, 750 Amps three-phase. It was tested severely, it was even exposed to more gamma than it would get in a Loss Of Coolant Accident (LOCA). But that does not mean that something else wouldn’t take it out. The switch was about eight feet high, six wide, four and a half deep, and had cables the size of your forearm running in and out. Inder IEEE-323 it was tested for everything anybody could think of, rad, seismic, cycling, humidity, fungus, and on and on.
The backup gensets for nuke plants are usually two or more MW, usually multi-megawatt class rigs.
They’re big. If they fit on a trailer, you’re talking of a Class 8 rig to pull them and then you’re going to need an over-weight (> 80K lbs) to pull them.
Here’s one of the more well known generator manufactures for stationary power backup for nuke plants, Fairbanks-Morse:
http://www.fairbanksmorse.com/file_system/stationarypowerbrochure.pdf
As you can see from the pictures, these puppies don’t get up and move that easily.
Yea, I was setting a lower possible size for these things at 2MW. I’ve seen some backup power systems spec’ed for nukes at multiples of 2MW, to add redundancy. The total portfolio had like eight of the suckers in parallel setups, with the possibility of two not online.
I love those monster, low-RPM diesels. Every time I get around one of those things, especially the compressed-air start engines, I giggle with glee like a little kid as they huff and puff to life.
My wife thinks it is most unseemly for a middle-aged man to carry on that way, especially around “just another stinky engine.”
Women just don’t get it.
There's nothing like the sound of an air starter, even on a small diesel, to scare the crap out of you if you don't know it's coming :^)
but wouldn’t the US military on Japanese bases or the Japanese military itself already have almost big-as-flatcar generators that could be tasked?
Could it be stale diesel fuel?
Maybe they do, but you can’t just pick them up and move them in a few hours, in a normal environment.
In an environment that’s been hit with a mammoth earthquake and tsunami, logistics problems are stupendous.
Even if you could fit one in a C5 Galaxy, where would you land it near the plant?
Nuclear problems are particularly troubling in Japan, which has 56 nuclear reactors, providing about 20% of the nation's electricity. Eleven reactors shut down as a result of the earthquake, as well as dozens of conventional fossil-fired or hydroelectric plants, leaving millions of people without electricity.
The solution is simple...fire up the windmills. Somebody should simply ask Obama how to do it.
The military has the capability to fly in those size sets. OR, they can simply hook two or three smaller ones together and bump up the capacity through a transformer..if they can find one.
To think of it now..since those plants on on the water...the navy can get them in there.
To be sure, the Japanese are most likely doing that very thing right now, I hope.
I just finished reading a book by Lyle Cummins about the early history (pre-1918) of the Diesel engine. Even back then, some of those MAN diesels were huge, a pair of them would barely fit in a WW1 U-boat.
The type air start I think he is talking about isnt what one would normally think about.
We had to put cherry blosum tourches into the air intake of the big FM and then open a special valve on each of the cylinders. So the chief would go...Number one, number two, number three etc until the thing took off. When he yelled for the next cylinder, the guy on the other would shut the valve on his. We had all the inspection plates off the side and the chief would watch which rod was going over center and was ready to prime.
That Fairbanks Morse (I think it was a FM if I remember right) had a 6-71 Detroit that ran the fuel transfer and water pumps for it.
That was way back in the day...early 70s.
Thanks for the info. Most people cannot comprehend how big the stuff you are describing. Unreal. My guess is no one expected a 9.1 earthquake. It was upped from 8.9. I hope they can get it under control. The poor people in Japan.
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