Just how long does it take to cool a reactor?

[MarillionFan]

It's not - even before this disaster which would undoubtedly push up insurance rates, reduce scale of builds (and thus increase cost of building less reactors) was not much lower than gas/reasonably clean coal, I mean like 15-20% difference - **** nuclear for such a small saving especially given that you'd need to have 100% of all power made by nuclear to get 15-20% cheaper energy, I repeat it **** it.

Price of uranium ain't cheap either, though it might be now since there will be less buyers. Frankly this whole "peaceful" nuclear tulip appeared because of desire to build nuclear weapons and having "peaceful" element was a way to shift costs to taxpayer without directly calling it military spending, clever trick that worked nicely some decades ago, but right now nuclear chickens are coming home to roost.

Right.

So the idea of using Nuclear is, that you are reducing the amount of fossil fuels(a source that is becoming more expensive and is diminishing in size) available.

Nuclear offers you a 'cleaner' form of energy. Basically meaning you're not digging up the entire planet.

What is interesting is, that the whole process is still based around turbines moved by steam. It's a sad indictment of human technology that we are still limited by that concept. Newcomen must be turning in his grave.

It is the over population of the planet that requires more and more resources to feed it. We are like a plague of locusts devouring the crops of a field are a limited by our abilities.

The question is, when will the discovery and leap in 'free energy' occur?

For now. It's Nuclear.

[MarillionFan]

My mate Tim (of the Cheshire mansion fame) could not sleep after stopping drinking. He could not sleep unless he had a few beers. The outcome was that he had a mild alchohol dependancy. He had to go through many sleepless nights and sweats to overcome the addiction.

Given the stress he has been under it was always on the cards.

Perhaps you have the same thing?

No bad thing to admit it, just good to recognise it and deal with it.

Grumble, grumble. Just knocked back a bottle of wine to take the edge off, so you may be right.

[Churchill]

Grumble, grumble. Just knocked back a bottle of wine to take the edge off, so you may be right.

Go and see a Doctor.

[centurian]

I mean perlease I can understand there are chain reactions after withdrawing the rods from the core

Actually "chain" reactions stop almost instantly - as soon as the control rods are inserted - a chain reaction being where a splitting uranium atom causes other atoms to split.

The problem is the "normal" radioactive decay of the isotopes produced when uranium atoms are split, typically iodine and caesium. These decay on their own without any stimulus - in fact little can be done to stop them radio-acting (i.e. decaying), so it's down to the normal rules of radioactive half-life. The half life of iodine is about 8 days

[VectraMan]

Actually "chain" reactions stop almost instantly - as soon as the control rods are inserted - a chain reaction being where a splitting uranium atom causes other atoms to split.

The problem is the "normal" radioactive decay of the isotopes produced when uranium atoms are split, typically iodine and caesium. These decay on their own without any stimulus - in fact little can be done to stop them radio-acting (i.e. decaying), so it's down to the normal rules of radioactive half-life. The half life of iodine is about 8 days

From what they were saying on the telly, this secondary process produces about 10% of the normal heat, which means with the rods inserted, the cooling system needs to get rid of 10% of the heat it deals with normally - doesn't sound too hard. And with the main reaction stopped, this process dies away rapidly (i.e. over days). So nearly a week later they ought to producing a fraction of the heat that they would be at normal operation.

I guess the irony is that if they hadn't shutdown the main reaction, the reactor probably would have continued producing power and there would be no crisis.

Dropping water from helicopters sounds like a last desperate solution and makes you wonder if Homer Simpson is in charge (I was trying to find a video of Homer saving the power plant from meltdown by going eeny-meeny-miney-moe and pressing a button at random).

[rhubarb]

Is this dragging on too long?

I believe they are jolly hot! Takes a while.

[NotAllThere]

Instead of water, they should drop liquid Xenon. That should cool things down.

[doodab]

From what they were saying on the telly, this secondary process produces about 10% of the normal heat, which means with the rods inserted, the cooling system needs to get rid of 10% of the heat it deals with normally - doesn't sound too hard. And with the main reaction stopped, this process dies away rapidly (i.e. over days). So nearly a week later they ought to producing a fraction of the heat that they would be at normal operation.

I guess the irony is that if they hadn't shutdown the main reaction, the reactor probably would have continued producing power and there would be no crisis.

Dropping water from helicopters sounds like a last desperate solution and makes you wonder if Homer Simpson is in charge (I was trying to find a video of Homer saving the power plant from meltdown by going eeny-meeny-miney-moe and pressing a button at random).

You're a project manager aren't you?

Fukushima I Nuclear Power Plant - Wikipedia, the free encyclopedia

Fukushima I – 1 460 MW
Fukushima I – 2 784 MW
Fukushima I – 3 784 MW
Fukushima I – 4 784 MW
Fukushima I – 5 784 MW
Fukushima I – 6 1100 MW

10% of 1GW (units 1 and 2) is 100MW. Allowing for inefficiencies in the power generation process that's probably 200MW of heat output that needs shifting.

A quick calculation based on specific heat capacity and latent heat of vaporisation of water, 1L @ 10 degrees C will require about 2650 kJ to boil, we have 200,000 kJ / s to get rid of, so we need about 80L of water a second to replenish the stuff that is turning to steam.

If you wish to avoid it turning to steam you have a much bigger problem, as most of the energy (2270 kJ) is absorbed by the vaporisation rather than the raising of temperature.

[MarillionFan]

You're a project manager aren't you?

Fukushima I Nuclear Power Plant - Wikipedia, the free encyclopedia

Fukushima I – 1 460 MW
Fukushima I – 2 784 MW
Fukushima I – 3 784 MW
Fukushima I – 4 784 MW
Fukushima I – 5 784 MW
Fukushima I – 6 1100 MW

10% of 1GW (units 1 and 2) is 100MW. Allowing for inefficiencies in the power generation process that's probably 200MW of heat output that needs shifting.

A quick calculation based on specific heat capacity and latent heat of vaporisation of water, 1L @ 10 degrees C will require about 2650 kJ to boil, we have 200,000 kJ / s to get rid of, so we need about 80L of water a second to replenish the stuff that is turning to steam.

If you wish to avoid it turning to steam you have a much bigger problem, as most of the energy (2270 kJ) is absorbed by the vaporisation rather than the raising of temperature.

I don't need to know the details. I want you to fix it.

Bloody techies.

[PAH]

Dropping water from helichopters does look a bit homer simpson but I guess the water cannon boats are now further inland than the reactors.

Isn't the whole area going to be somewhat polluted by dirty water now they've been pumping in seawater (that has to go somewhere) and now splashing it around?

If only they'd built a great big wall around the reactor in the first place.