Beginners guide to nuclear power stations ?

More problems at nuclear plants.
http://www.bbc.co.uk/news/world-asia-pacific-12729138

gonefishin – Member

Given that the total death toll from Chernobyl is estimated at about 60 it’s not actually that big a claim. Plus all the cancer caused by the radiation and of course lots of other ill health.
http://www.who.int/mediacentre/news/releases/2005/pr38/en/index.html

Another vented hydrogen ignition. But the vicinity seems safe thanks to the designers for building such good filtering and strong containment. More injures to plant operators though 🙁

Despite how it looks, it seems better managed that 3 mile island where the core boiled-dry. They at least have a means to manage the decay-heat of the cores. I guess the IAEA will be looking at more redundancy in pump-driven cooling systems and also at pressure venting. I wonder if the designers realised that these venting scenarios would be so dangerous to perform.

Anyone got any idea how many times any other sort of power station has had to have a 30 mile radius evacuated?

Seems to me the penalty for failure is pretty severe, so probably worth taking into account in the decsion making process on how much to invest into alternative energies.

Seems to me the penalty for failure is pretty severe, so probably worth taking into account in the decsion making process on how much to invest into alternative energies.

http://manhaz.cyf.gov.pl/manhaz/strona_konferencja_EAE-2001/15%20-%20Polenp~1.pdf

http://nextbigfuture.com/2008/03/deaths-per-twh-for-all-energy-sources.html

had to do it…..

I doesn’t seem like core breach would happen with this design – it’s not Chernobyl. The local evac is to completely prevent any risk from radioactive Iodine and Cesium, very small amounts of which have been released by the steam venting.

How many people have died from hydro power stations exploding?

Not exploding, but dams ocasionaly burst, which is bad especialy when historicaly people live near rivers, on which dams tend to be built upstream in the mountains. Theres a film you might have seen, it’s called Dambusters, it involves a lot of people dying.

Nuclear power tends to be in the arse end of nowhere.

Add into that the greater day to day danger of accidents arround hydro plants which are more often in less developed countries with lower HSE standards and youve got a gentle drip drip drip of fatalities, compared the once a decade nuclear problem.

There were a lot of deaths involved in the building of UK hydro schemes back in the day when H&S didn’t exist, there was quite an interesting program about it on telly not too long ago. It is very different these days though someone did die in a construction incident a year or two ago iirc. I think its fair to say there is a lot more disruption from nuclear power going pete tong.

Olly – Member

a so called “melt down” should be impossible, if it isnt, someone is going to have to answer some questions with some damn good answers.

In Chernobyl, the rods were lowered into the reactor, in order to make the heat. when the control systems failed, the weight of the rods, held them in the reactor under gravity, and they could be pulled out.

since chernobyl, its been flipped.

the rods default position (due to gravity mainly) is OUT, not IN.
the rods have to be actively held into the core, and if anything goes wiggy, they should fall out due to gravity.

a high tech dead mans handle arrangement.

if they pump that moves the water around the reactor has failed, no one is getting power ANYWAY, so they will just shut it down and it will begin to cool.

surely?!

Yes, the main reaction was stopped, it is the (significant amount of!) residual heat which is causing problems.

Have a read of this:
http://bravenewclimate.com/2011/03/13/fukushima-simple-explanation/

1. Likely timeline of incident is:

a. Reactors 1, 2 and 3 were in operation at Fukushima Daiichi nuclear power plant when the earthquake struck.

b. all three reactors were shut down and control rods were inserted when earthquake struck.

c. Cooling was maintained to remove decay heat

d. decay heat drops rapidly on reactor shut down (e.g a 3GW reactor will reduce to 200MW decay heat after 1s and 50MW after 1 hour… But takes long time (3-6months!) to reduce to negligible levels)

e. sometime (?1hr) later tsunami struck and mains power was lost to coolant circuit on Unit 1

f. Diesel generators also failed when tsunami hit so cooling was run by backup batteries for 7-8 hours

g. Other emergency diesel generators brought in but insufficient to run pumps

h. loss of coolant leads to fuel rods no longer being cooled by two phase flow (it is a Boiing water Reactor) and eventually get hot enough to recat with steam to produce Hydrogen.

I think its fair to say there is a lot more disruption from nuclear power going pete tong.

Assuming the absolute worst case scenario statistics, how many deaths from Chernoble? I seem to remember 10,000 being banded about? And we’re unlikely to repeat that.

How many people live downstream of the Hoover dam? 10x that? 100x that?

My point is that nuclear has a very good safety record, and if it goes wrong it’s not quite as horrific as you might be lead to believe and the consequences of other forms of generation going wrong are just as bad.

By default the current reactors are all unsafe-by-default. If left to their own devices without active-cooling they go super-critical.

A better way would be safe-by-defualt, where being left alone cause the reaction to slow to a stop without external input of power or otherwise.

LFTR does this, well worth watching some of the videos (mostly the same talks, various different lengths with associated brevity) on YT. http://www.youtube.com/results?search_query=liquid+thorium&aq=f

Unfortunately current regulation is not setup for either these or travelling wave reactors, so even starting development again has been a no-no since the late 70s.

I read that India was developing Thorium. And Thorium is more abundant than Uranium. Why not Thorium then?

The google tec talk was very interesting. I liked:

As the grid demands more from the fluid it goes back colder. The colder the fluid gets, the denser it is, the more energetic the reaction. So the reaction is to an extent, demand lead.

The solid “plug” of reactive material at the bottom of the core is maintained by fan cooling. If the core overheats, or if external electrical supply fails, the plug melts and the fluid pours into a separator catch tray, where it is non-reactive. You then re-heat the fluid in the tray and re-start the pump to put it back in the core to resume. At the Oakridge experimental plant, they did this over every weekend so they could have the weekends off.

That is very operationally flexible and safe. The barriers would seem to be setting up the infrastructure. The Uranium-based infrastructure we have today was largely paid for by the weapons programme.

My point is that nuclear has a very good safety record, and if it goes wrong it’s not quite as horrific as you might be lead to believe and the consequences of other forms of generation going wrong are just as bad.

Very good? not as horrific? What happens when a coal one breaks down how many people get cancer and for how long can you not live in the vacinity with conventional power? etc
As for the hoover dam at 600 ft thick at its base and 45 foot at its top it is hard to think what could be done to break it.Yes it could happen [ i suppose a meteor could hit it] but nuclear ones have occured numerous times. I am not certain that it is wise to compare hypothetical scenarios with ones that have occured when assessing risk

i wonder what would happen?

There are other unstable landmasses around, i wonder if any coastal nuclear plants have anything in the emergency manual just in case?

Some of the comments on the first page are starting to look very silly. Laughable even were it a laughing matter. Forums are great in the way posts stick around and some people demonsrate how easily duped they are.

Keep up the good work. What I know about this stuff could be written on the back of an envelope, however, I’ve been listening for the word “boron”, haven’t heard it and can’t help wondering why not.

Every single system designed by human beings, thus far, has, at some point, failed.
Humans make mistakes – it’s in our nature.

Sounds much cooler if you imagine it in Darth Vaders voice.

I reckon that if an older generation nuclear reactor can take a hit from one of the largest earthquakes in history, it is a remarkable success and my best wishes are with them all.

I reckon that if an older generation nuclear reactor can take a hit from one of the largest earthquakes in history, it is a remarkable success…….

Yeah well I think it is now pretty well established that an older generation nuclear reactor cannot take a hit from one of the largest earthquakes in history – or at least the consequences of one of the largest earthquakes in history. Otherwise there wouldn’t any problems today with three nuclear power plants in Japan.

I’ve been listening for the word “boron”, haven’t heard it and can’t help wondering why not

Is boron still used as control rods? It’s been a long time since I studied Nuclear reactors, and even then it was AGRs which I’m guessing isn’t the type of reactor that’s causing the problems in Japan.

What happens when a coal one breaks down how many people get cancer and for how long can you not live in the vacinity with conventional power?

Well there are plenty of other nasties that get given off by conventional power stations, and I’m going to go out on limb and say that quite a few of them are carcinogens. Apparently about 20-30 years is how long you have to stay out the area. There are people who live in that area now. Granted not everything there is sweetness and light but there is life doing rather well there. Bear in mind that it is very difficult to get a proper idea of just how many people have died as a direct result of the disaster. What can be said however is that that, the worst nuclear disaster in history doesn’t even come close to the worst industrial disaster.

And the other side[/url] A good read

Otherwise there wouldn’t any problems today with three nuclear power plants in Japan.

To be fair they are taking all the right precautions and the story comes out sounding like they might pull it off. If they can keep the damage to a minimum I am sure it will more than justify it’s service to the people of Japan.

Not saying it is a foregone conclusion, and I wish them all the luck, but it could turn out to be a bit of cracking PR for the nuclear industry.

the story comes out sounding like they might pull it off.

Yep, let’s hope they do. And let’s also hope that lessons are learnt. Although by their very nature, unforeseen circumstances are very difficult to plan for.

So the Japanese are efficiently working through problems caused by a once in 200year or more earthquake and the tsunami. Meanwhile, the media and people who didn’t go to school are running round in a flap.

We shut down the nukes and we have to burn more coal.

A coal power station emits 100x more radioactive material than a nuclear station that generates the same energy.

Coal contains uranium and thorium, both radioactive elements. They occur in trace amounts in natural coal, and so are not a problem whilst the coal is in the ground. However, when coal is burned into fly ash, uranium and thorium are concentrated at up to 10 times their original levels.

This fly ash spreads further and blankets a wider area than the radiation produced by a nuclear plant.

Nice to be a hippy sitting in a warm house whinging about the environment, dude. But you want your house warm, and the internet working to chat to the other dudes online.

Nuclear fuel is the most environmentally friendly choice we have at the moment. As others have said, in 30 years time renewables might be a go-er, but not yet.

The operators must have been horrified when they saw the primary coolant levels dropping away and no means to pump around fresh coolant. There’s a certain amount of improv going on e.g. using fire pumps to put sea water into the core. I bet that isn’t in the manual. I read that they are going to “ventilate” i.e. drill holds in the outer building before steam venting again, to prevent explosive build up of hydrogen.

I hope they get medals.

Meanwhile, the media and people who didn’t go to school are running round in a flap.

I bet I’m a darn sight more relaxed and sleeping better than the nuclear bods in Japan.

The answer isn’t producing ever more electricity, it’s cutting demand, particularly peak demand. I bought a 30s house which already had double glazing and roof insulation,and reduced gas consumption from 600m3/year to 220m3/year just by futher insulating and adding a solar hot water heater. I could have cut it to about 150m3/year by changing to a condensing boiler but cut the gas off and fitted a wood burner instead. Wood consumption is curently 4m3/year but with yet more insulation that will go down.

Now if everyoen does the same then renewables become viable now.

Assuming the absolute worst case scenario statistics, how many deaths from Chernoble? I seem to remember 10,000 being banded about? And we’re unlikely to repeat that.

Something like that, in theory, but it was all crap. 10,000 people will die 20 minutes early. Actual deaths are so negligible that they can’t spot them in the population.

who are you who is so wise in the ways of science 🙄
Cancer is negligible amd makes you die 10 mins early?

The digest, based on a three-volume, 600-page report and incorporating the work of hundreds of scientists, economists and health experts, assesses the 20-year impact of the largest nuclear accident in history

what did these folk think? 6,850-9,000 deaths mainly cancer. roughly 1 million had dangerously high levels of radiation and other scientific , and published research from various locations [ you can google I assume] have estimates ranging up to 1 million. there is also an increase in genetic sisorders/mutations and child mortality rates which are statistically signifcant but difficult to prove direct causality.
Basically you are talking nonesense but you could show your faith and relocate to near the disaster site…if you were allowed because it is still not safe.

I’ve just been reading about Chernobyl. It was a dreadful disaster because the reactor design was poorly behaved so that operator errors could and did lead to overheat. And the design lacked a vessel strong enough to contain an overheated core. Very shonky design.

What happens when a coal one breaks down how many people get cancer

some estimates suggest 12000 people die EVERY year worldwide from coal mining; the fact that you can’t see those deaths and they rarely make the press doesn’t make our reliance on coal (from countries with relatively poor safety standards) morally ok.

How many people suffer short term or long term effects of pollution from coal fired power stations every day? How many more may be affected or displaced by the long term effects of climate change if the predictions are true.

and for how long can you not live in the vacinity with conventional power? etc

I don’t think there is any talk of long term evacuation in Japan? Conventional fuels also cause short term localised evacuations during accidents (Bruncefield, being a recent example on our own shores) as well as long term loss of housing (Aberfan again being an example close to home).

As for the hoover dam at 600 ft thick at its base and 45 foot at its top it is hard to think what could be done to break it.

well I’m no geologists but I’d guess that one of the world’s biggest ever earthquakes on the doorstep might cause the engineers to be at least checking their calculations!

In fact, although not as sexy a story as the nuclear issue, just along the road a dam (don’t know if it was for hydro or water) broke in the quake and washed away thousands of houses.

And that problem is not unique to Japan. Indeed you may remember the quake in China last year damaged a dam which threatended the homes and lives of at least 100,000 people.

Yes it could happen [ i suppose a meteor could hit it] but nuclear ones have occured numerous times.

actually there have been very few nuclear accidents which have caused significant casualties (and even fewer members of the public have been killed). You are simply remembering the nuclear incidents over the others.

I am not certain that it is wise to compare hypothetical scenarios with ones that have occured when assessing risk

only focussing on things that have already happened is a bad idea in managing risk – its usually much easier to avoid repeating the same **** up – the hard bit is guessing the unkown!

dmjb4 – Member

So the Japanese are efficiently working through problems caused by a once in 200year or more earthquake and the tsunami. Meanwhile, the media and people who didn’t go to school are running round in a flap.

We have had nuclear power for what 50 years? How many serious accidents and releases of radioactivity? How many more “nearly” until one blows properly?

A coal power station emits 100x more radioactive material than a nuclear station that generates the same energy.

Only so long as you ignore the issue of waste – low medium and high level.

There remain too issues that mean nukes are not the answer. Waste and decommissioning.

coal is intresting as the mining is dangerous for sure but not sure this is rlevant pr se as we are discusssing the actual power genration stations not the method you get the fuel. You would need to give deaths for coal fired fuels stations to compare them to nucleur or we are not really comparing the same thing.
climate change is not a debate for here but oil is far more critical than coal as is is eating meat.
how many nucleur reactors would survive an earthquake? I suspect a dam is more likely to survive but I dont actually know. Nor do I expect google to answer it for either of us. i assume they dont build them anywhere near know fault areas.

there have been very few nuclear accidents which have caused significant casualties (and even fewer members of the public have been killed). You are simply remembering the nuclear incidents over the others.

A fair point but you may be doing the opposite. I assume if we blow up all the dams and all the nucleur power stations more of us would die from the later than the former. I am less sure that this proves my point or has any bearing but I it seems like a nice piece of hyperbole so it can stay 😉

In many ways they are like planes we all know they are safe if nothing goes wrong but when they go wrong the effects are fairly catastrophic.
i accept this one has not gone wrong and is still contained and highly likely to remain so.

Junkyard – Member

coal is intresting as the mining is dangerous for sure but not sure this is rlevant pr se as we are discusssing the actual power genration stations not the method you get the fuel. You would need to give deaths for coal fired fuels stations to compare them to nucleur or we are not really comparing the same thing.

I ain’t buying that. Surely theh only faior comparision is total deaths per kilowatt hr of leccy we get out. Mining ( some folk die urainium mining as well I guess) transporting, generating, emmssions deaths.

that what i was [trying to] saying TJ
perhaps we both spell so badly no one can understand us?

TJ – We have had nuclear power for what 50 years? How many serious accidents and releases of radioactivity? How many more “nearly” until one blows properly?

Wikipedia suggests about 20, most of which had no fatalities! I think the problem is the way this is presented in the media – we assume melt down = chernobyl. It doesn’t, melt down means a dead reactor and a very localised (and extremely expensive) mess to clear up. In fact most people I talked to in the last few days seem to think a nuclear reactor going bad is like a nuclear bomb going off – its not (its much more like the sort of dirty bomb Al Quaedia may be trying to build than a real nuke that Iran may be working on).

But I agree with you it is waste (and decomissioning) which are the barriers to nuclear rather than safety per se.

junkyard – A fair point but you may be doing the opposite. I assume if we blow up all the dams and all the nucleur power stations more of us would die from the later than the former. I am less sure that this proves my point or has any baring but I it seems like a noc epice of hyprbole so it can stay

I don’t think I am – I’m not ardently in favour of nuclear (but I do get annoyed when its dismissed as part of the solution because of a bad rep). I’m not sure which would cause more casualties, but I’m fairly sure if you did both then more people would die from not having access to power and all that goes with it than from the disasters themselves!

Do you also refuse to travel by plane? I mean, it must be way more dangerous than driving, wasn’t there a plane crash on TV last year?

A few sensational nuclear disasters get the news, but the tonnes of carbon and radiation emitted over the same period from burning coal have caused more harm.

I’d prefer nuclear waste buried several miles below my house to a slag heap next to it? Wouldn’t you?

some estimates suggest 12000 people die EVERY year worldwide from coal mining

That is a shocking figure. On the plus side, that’s probably not that far from the maximum possible figure. You might get a 10% or 20% increase in any given year, but you would not get 100% or 200% increase in any one year. Well, not without some sort of pre warning that fatalities were stacking up. So that’s fairly reassuring.

Another shocking figure is that, a large meteorite killed off 90% of all species and it took life on Earth 30 million years to recover. The good news is, that almost no one has died as the result of a meteorite for 250 million years.

Which all goes to prove, that I have absolutely no idea whatsoever what my chances are, of dying from a coal, nuclear, or meteorite, related death. I am surprisingly unbothered though……maybe I should be?

Whatever the merits (or not – and I’m still inclined to view the industry as a massive white elephant) of nuclear…. hats off to the bravery of the engineering & other personnel on the ground.