Aircraft engine will only blow up if the oil pump fails or birdies fly into it (A380 Trent engine had an inherent design fault) , then we can shut it down and do an emergency landing... Not so simple with a Nuclear reactor. Jet engines use the fact they travel at 30,000 Feet to be a cooling system (it's very cold at that height) ... Reactors don't have that luxury.
Earthquake in Japan....9.0...ouch!
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Aircraft engine will only blow up if the oil pump fails or birdies fly into it (A380 Trent engine had an inherent design fault) , then we can shut it down and do an emergency landing... Not so simple with a Nuclear reactor. Jet engines use the fact they travel at 30,000 Feet to be a cooling system (it's very cold at that height) ... Reactors don't have that luxury.
Caporegime
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Well the really bad thing is, afaik theres essentially, in line with the top of a reactor, another level of concrete above which is the cooling pond, though theres an access hatch to the reactor obviously to get the rods in and out of the reactor. The real danger is the rods getting uncovered, heating up melting AND melting through the concrete(which in itself I believe creates radioactive concrete by products) and right into the reactors containment area.
So if the plant fails completely you have reactor fuel burning through reactor casing into the bottom of a sealed lower containment building, and potentially spent fuel rods heating up and burning through into the lower containment building making a nice big hole through which basically everything radioactive can get into the air from. Worse still, it goes through the bottom level of concrete aswell and into ground water, the ultra worse case scenarios really are pretty grim, and SHOULDN'T get there, but shouldn't and can't aren't the same thing.
AFAIK newer, better or less, cheap sites will have the spent fuel ponds in a different building, or completely offsite to the reactors.
I mean the problem is, at some level they have to offered not just improved green house gases and the like to be built over coal/oil plants, frankly, they need to be pretty profitable or they won't run them. Would it be safer if all the reactor buildings were another 200metres apart from each other, sure, would that mean 4 times as much land, harder to find sites and vastly more expensive building and sorting out power/access to water further apart, etc, etc, yes. I mean, lets say for example reactor 4 was savable but as today they had to cool reactor 3 by quite daft methods just to drop radiation enough to get to reactor 4, and by that time(it took over a day to get cooling operations started) reactor 4 has gone from in danger to nuclear chain reaction back online.
The radiation above the plants, 250milliSv right at 30m, 90mSv at 90m, 5 at circa 300metres. If they were much further apart simply dealing with the reactors individually would have been FAR easier than it was today.
Soldato
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What cooling medium would be sufficient underground compared to the sea?
Soldato
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Months I am afraid it will be not years.
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With regard to power supplies. I can only comment for the CEGB not Japan.
Typically you have station electrcity supply boards which are powered from the national grid. And Unit electricity supply boards which can be fed from the station board or from the unit generator transformer (which is the electricty the unit is making). Common systems like cooling water are powered from station boards. Other systems like feed pumps, water pumps or oil pumps generally have an A and a B the A might be from the unit board and the B from the station board. So both can be supplied from the grid but A can additionally be supplied from the unit's own generation when running. This allows you to use your own electricity which should be cheaper than buying it off the grid. Cooling water is not normally self supplied, the grid is considered a more secure supply than the unit which may trip at any moment.
I can go into more depth if necessary.
Typically you have station electrcity supply boards which are powered from the national grid. And Unit electricity supply boards which can be fed from the station board or from the unit generator transformer (which is the electricty the unit is making). Common systems like cooling water are powered from station boards. Other systems like feed pumps, water pumps or oil pumps generally have an A and a B the A might be from the unit board and the B from the station board. So both can be supplied from the grid but A can additionally be supplied from the unit's own generation when running. This allows you to use your own electricity which should be cheaper than buying it off the grid. Cooling water is not normally self supplied, the grid is considered a more secure supply than the unit which may trip at any moment.
I can go into more depth if necessary.
Depends entirely on the quantity of radiation they've recieved and what the real truth is about it all right now (seeing as we can't believe the media)
Soldato
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Yes I understand that, my fear is it will be months not years.
Pump the Seawater underground? Whatever methods they use to cool the Reactors.... put them deep underground in a bunker so they cannot fail. Im not sure. The Japanese engineers are going to be much smarter than me, but why didn't they do this if the cooling system is so important???? Their backup system was Diesel generators???
The reactors have to be shut down as the quake could damage them or their ancillary systems. The fact they failed due to power loss during cool down in no way means they survived the quake completely unscathed or would not have failed even more seriously. Other nuclear reactors hit by large earthquakes in Japan have been subjected to years of inspection before coming back online.
The Trent engine also sent chunks of turbine blade through the wing and could easily have brought the plane down.
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^^ the A380 that suffered that failure was EXTREMELY lucky. I mean ridiculously so!
The engine was designed to withstand a blowout including blade disintegration, yet still be able to land safely. The outer shell of the engine is designed to contain such a problem and prevent debris from damaging the wing (in particular the leading edge slats). What happened on the A380 flight could never have brought the plane down unless a fire broke out, which in any case can be controlled using standard extinguishers (deployed from the flight deck).
I know this because....
Although they have failed in this situation, I guess the great thing about using diesel generators is the simplicity of them. A complex backup system is more likely to fail and be harder to repair than something simple that would also do the job in most 'normal' situations when they would be needed.The Japanese engineers are going to be much smarter than me, but why didn't they do this if the cooling system is so important???? Their backup system was Diesel generators???
Until this disaster the backup systems were deemed adequate. With the new knowledge gleaned from this accident future designs will be improved and existing plants upgraded.Pump the Seawater underground? Whatever methods they use to cool the Reactors.... put them deep underground in a bunker so they cannot fail. Im not sure. The Japanese engineers are going to be much smarter than me, but why didn't they do this if the cooling system is so important???? Their backup system was Diesel generators???
Quite possibly over the last 40 years complacency set in and those in power ignored new research and findings but that is something that will come out in due course
What's wrong with diesel generators? Virtually all first line back up power generation from hospitals to server farms to nuclear bunkers are diesel. They are reliable, easy to maintain and cheap to run.
But how come they didn't have a fail safe system in place? If the cooling system is so important (which it is) why didn't they put said system under the ground and make sure it can't fail (if such a thing exists) ?? They could have have 2, maybe 3 cooling systems working under the ground which would be almost impossible to fail??
Caporegime
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The chopper pilots supposedly had a reading of around 60MilliSv's after landing, they were flying at around 300ft where the readings were just under 90milliSv, but keep in mind theres a pretty big chunk of metal between the radiation and them, and the reason one crew is only allowed to do 40minutes a day, and even the choppers, they won't put another crew in the same chopper, but a diff chopper because radioactivity of the chopper would increase and effect the crews more. 60millisv's isn't nothing but its not little either.
Remember the average dose is supposedly around 2.4millisv a year, a little more or less depending on where and how you live, flying all over the world or sick and having xrays all year. But also 2.4millisv's is spread over that entire year, damaged cells repair, 60milliSv in a year wouldn't be much, but 60millisv in 40 minutes is dramatically more damaging than spread over a year. Proper radiation sickness doesn't really hit its lowest levels till 1000milliSv's and that level is very rarely fatal.
So basically they aren't in any immediate danger, far from it, but an increased chance of cancer in their lives, probably, if they get cancer will it be immediately obvious this is the cause, not at all.
Remember the average dose is supposedly around 2.4millisv a year, a little more or less depending on where and how you live, flying all over the world or sick and having xrays all year. But also 2.4millisv's is spread over that entire year, damaged cells repair, 60milliSv in a year wouldn't be much, but 60millisv in 40 minutes is dramatically more damaging than spread over a year. Proper radiation sickness doesn't really hit its lowest levels till 1000milliSv's and that level is very rarely fatal.
So basically they aren't in any immediate danger, far from it, but an increased chance of cancer in their lives, probably, if they get cancer will it be immediately obvious this is the cause, not at all.
Look what happened to them !! Put them underground and power them from the reactor for starters !
Caporegime
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This has been answered, the diesel engines WERE UNDERGROUND. Thats not the best place for them when you have massive massive flooding in the area though, and flooding is the reason they failed. IE underground rather than on the 5th floor of a support building is the reason they failed. LIke I said, a future revision of a design close to this reactor would probably, from a perspective of this accident, have a sealed underground unit and a large chimney stack for air supply, so if there was flooding it wouldn't get into the underground area nor would it comprimise the airflow to the building.
For all we know the building is well sealed to flooding but the earthquake caused a crack that let it get flooded, every last piece of info isn't available and won't be available for some time. Chernobyl still has people going back, checking data and releasing new reports. As a race we've learnt more from our mistakes and accidents than from pretty much anything else.
I agree with all the above, just to correct you on the significance of the difference between the max force of the earthquake and the one that happened a few days ago - it's 100 times bigger, not 10 (which is mind boggling tbh knowing how powerful 7.5 earthquakes are).
What video did you have on mind?
That is retarded. I would laugh at people buying these now.
Anyone knows of any reliable sources that report on the nuclear plant workers' health condition? There's plenty of sensationalist articles and videos that talk rubbish and I am interested if their life is really in danger or are they exposed to minor health risk atm.
Why did they fail??? Surely the very cooling system could be powered from the Reactor on it's own, no????