Beginners guide to nuclear power stations ?

I’ve been scouting for the most alarmist/innacturate press and this is the best I’ve come up with: The Mirror[/url]. Surely they should be reporting celeb gossip, not serious news?

“How many more “nearly” until one blows properly?”

Reactor fuel is not explosive. The burning reactor core exposed to the atmosphere at Chernobyl was almost the worst that can happen.

I am quite taken with this liquid fluoride thorium reactor mentioned earlier. Although the chemistry and reactions are more complex, it’s operations seem way simpler and safer.

The pebble bed reactor is another worthwhile self-moderating design. I think SA are building some of these.

A pebble-bed reactor thus can have all of its supporting machinery fail, and the reactor will not crack, melt, explode or spew hazardous wastes. It simply goes up to a designed “idle” temperature, and stays there. In that state, the reactor vessel radiates heat, but the vessel and fuel spheres remain intact and undamaged. The machinery can be repaired or the fuel can be removed. These safety features were tested (and filmed) with the German AVR reactor.[6]. All the control rods were removed, and the coolant flow was halted. Afterward, the fuel balls were sampled and examined for damage and there was none.

Why not Thorium then?

Answered by:

The Uranium-based infrastructure we have today was largely paid for by the weapons programme.

Exactly. Nuclear power was a nice side-product discovered while making weapons-grade materials. The legislation, especially in the US and Europe, is very much geared towards Uranium infrastructure, with other options being ignored as a result.

Bill Gates is a big investor in travelling-wave research, and had been hoping that Japan would give permission for some small-scale experimental reactors.

I’ve been scouting for the most alarmist/innacturate press and this is the best I’ve come up with

Well if alarmist is what you want, then this takes some beating :

U.S.S. Ronald Reagan hit by month’s radiation in just one hour

The U.S.S. Ronald Reagan was around 100 miles (160km) offshore when low-level radioactive contamination was detected from the stricken Fukushima plant.

Low radiation levels were detected on 17 members of the crew on three helicopters as they returned to the ship after delivering aid to the devastated city of Sendai.

Most of the radiation was found on the clothing of the 17-man crew, but also on one’s skin. The sailors were said to not have experienced ill-effects following the incident.

Contamination was found on the helicopters, which were scrubbed down on landing.

Lots of interesting thoughts in regard to nuclear power, most people forget the Windscale fire – the most probable source of the Cs-137 in the Cumbria / Lake District area rather than the fall out from Chernobyl.

What happens in Japan will depend on the ability of the people on the ground to maintain cooling to remove the residual decay heat from the core and prevent the loss of fuel pin geometry (the clad melts). If this happens there is the risk of fission product release to the environment through either bypass of the containment boundary (eg relief valve lift) or damage to the primary containment.

As an aside the Japanese nuclear industry has a history of misleading the public or attempting to cover up nuclear incidents, which is why the Japanese public seem a bit nervous.

The accidents at Windscale, Three Mile Island, Chernobyl and Tokaimura all had different root causes but none has covered the nuclear industry in glory. The near miss with the Davis Besse reactor head is another example of how things can go wrong.

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

So given there hasn’t been an accident with a current generation nuclear generator, that’s a purely hypothetical risk, and you can’t compare with more dangerous methods of energy production in which fatal accidents have occurred, like hydropower

Well if alarmist is what you want, then this takes some beating :

U.S.S. Ronald Reagan hit by month’s radiation in just one hour

Top quote from that in a picture caption – just in case you’d missed the connection between a nuclear reactor and nuclear bombs:

The towns destroyed by the tsunami look very similar to Hiroshima in 1945

Maybe a better picture caption would have been :

The towns destroyed by the tsunami look very similar to how Ronald Reagan would have liked North Korea to look

Well there has been an explosion at reactor 3, this is of greater concern than the others as it contains mixed oxide fuel – a mixture of uranium and plutonium oxides. With Tepco having admitted to having uncovered the fuel on 2 separate occasions it is likely that a zircaloy fuel element will have ruptured leading to fission product release within the primary containment. As they have been venting to the secondary and tertiary containment, it is likely that there will have been fission product release following the recent explosion.

Ps The accident progression is what would be expected for the loss of cooling scenario that has occurred.

So given there hasn’t been an accident with a current generation nuclear generator, that’s a purely hypothetical risk, and you can’t compare with more dangerous methods of energy production in which fatal accidents have occurred, like hydropower

Whether or not more modern reactors are safer isn’t really the point.

In the past I’ve heard plenty of people expounding about how wonderful nuclear power is in Japan, and how they have a flawless safety record. Everybody has a flawless safety record until the very moment that they haven’t.

If these old reactors were inherantly less safe than current reactors, then surely it would have been a good idea to either improve their saftey features or shut them down some time ago. But IMO that’s not how the nuclear industry works. Instead it relies on the support of a bunch of technophiles who think that everything can be managed, even when the evidence is right in front of them.

I don’t give a sh1t if the UK is unlikely to suffer from a 9.0 earthquake. I don’t want a new generation of Nuclear Power here, because it is usually not the foreseeable problems that go bad (except in this case!) but the unforseeable ones, and having a bunch of appologists for the nuclear industry telling me how they are going to make sure that ‘lessons are learned’ or that ‘technology is better now’ or ‘that shouldn’t have happened’ doesn’t comfort me very much.

I’m afraid that no amount of statistics about numbers of coal miners killed will ever convice me that nuclear is a good idea. Surely the correct response would be to call for coal mining to be made safer? Or better still to start to finally accept that our existing energy usage is unsustainable and try to at least start cutting back on consumption?

Anyway, I’m sure I’ll be kept warm enough basking in the flames of the forum, but I’m hoping that this latest wake up call will at least rouse a few more people from their technology induced stupors.

No flaming Rightplace. Just a request to pop out to the shops and buy a bagful of 3W LED light bulbs and a couple of 36W strip lights because those “economy bulbs” your government gave you use are energy greedy (as well as providing poor lighting and taking ages to warm up) and you can start reducing your personal consumption today. Sorry, but all those pretty halogen lights have to go to the recycling centre.

Buy some multi-socket blocks with a switch too so it’s easy to switch off the amp/TV/sat box/ cable box/DVD player and 3W LED table lamp in one go when you leave the room.

Buy some multi-socket blocks with a switch too so it’s easy to switch off the amp/TV/sat box/ cable box/DVD player and 3W LED table lamp in one go when you leave the room.

There we go, ready for a meltdown of my own now 8)

As accidents go, the one at Fukushima was predictable – earthquakes and tsunami tend to go together. The Windscale fire was a result of a drive to produce Plutonium for the nuclear weapons programme hence an air cooled graphite moderated reactor with only a few filters preventing release of radioactive material into the environment.

TMI was the result of a faulty meter reading and the failure of the regulator system in the US that assumes you are safe if you have met certain targets rather than challenging everything to ensure the plant is safe. Again see the Davis besse reactor head – corrosion due to dissimilar metals around the control rod penetrations in the RPV head.

Chernobyl was the product of political pressure and poor design. The reactor had a significant -ve temperature reactivity coefficient below 20% full power that in the operating rules stated that if you went below 20% full power you need to restart the reactor. Political pressure was placed to run a test at 4% full power (a turbine overrun test) and then continue operating at power. To do this the operators had to defeat all the safety systems and pull the control rods out to a position that only the then president of USSR could authorise. Leading to the prompt criticality accident, the explosion and fire.

The generation 4 reactor designs are very different in that previously a lot of safety was reliant on operator action or active control systems. The latest designs have numerous fail safes and are designed with walk away capability ie you put the control rods in and if you walk away and do nothing the plant will passively sit there.

The next evolution of the the Fukushima plant accident will be that as the cooling fails (no one adding water), the fuel will heat up and the steam atmosphere in the reactor will oxidise the zircaloy fuel clad (an exothermic reaction) at between 600 and 800 deg C producing more hydrogen. As the exothermic zircaloy steam reaction drives up the temperature of the clad along with the residual heat in the fuel, at some point there will be further clad failure leading to a loss of reactor core integrity. This is the expected and worst case scenario.

With the clad failure, the boron that has been added and the control rods (which will also mechanically fail) should prevent any criticality issues.

There is potential for fire in each reactor due to the temperatures involved (even concrete will burn if hot enough), and failure of the primary containment through another hydrogen explosion should this not be being vented.

I have never liked the BWR design as I always felt the design was fundamentally flawed from a safety point of view. Having to drive control rods in against gravity rather than having them drop in under gravity to shut down a reactor in an emergency always seemed to put an undue risk of failure on one system.

The issue with nuclear power always has been that political and commercial pressure to keep operating will always lead to a situation where requirement to keep operating the reactor to produce those MW will at some point clash with safety.

I’m afraid that no amount of statistics about numbers of coal miners killed will ever convice me that nuclear is a good idea. Surely the correct response would be to call for coal mining to be made safer?

Not necessarily world populations are rising unsustainably! 😉 Seriously though coal mining casualties aren’t an argument “for” nuclear, they are a way of putting some rational sense around claims that nuclear is “unsafe”. The reality is people die from all forms of industrial activity, to decide which is “safer” you need a way of measuring the total risk across the total supply chain.

Or better still to start to finally accept that our existing energy usage is unsustainable and try to at least start cutting back on consumption?

Whilst I accept there is some waste, you need to recognise that electricty brings a lot of benefits to the world and improvements not only to quality of life, but standards of living, health and economic growth. There simply isn’t any technology around which would let us turn off all the coal and nuclear power stations over say the next ten years and expect the gap filled – so it is a choice, coal, nuclear (a mix) or go back to some pre-victorian standard of living. Anyone using a computer to have this argument can’t be treated seriously for saying that we waste electricity!

I disagree Poly. Households could reduce consumption by 75% and renewables could meet that demand within ten years. You simply need the kind of commitment that went into producing weapons for WWII or the cold war.

As accidents go, the one at Fukushima was predictable

Really……everyone expected the safety backup systems in 3 out of the 8 reactors to fail ?

Well they need to get their PR act together then – the message I’m getting isn’t, “it’s alright everyone, this is suppose to be happening – we predicted it all”

Haven’t read all of this thread yet but read this article this morning, ”Why I am not worried about Japan’s nuclear reactors.”[/url]

renewables could meet that demand within ten years.

OK – educate me – which renewables are going to provide 25% of our current total consumption as baseload? (for the sake of argument I’ll ignore the fact that decreasing household consumption by 75% wouldn’t decrease total consumption by anywhere near that much)

. Anyone using a computer to have this argument can’t be treated seriously for saying that we waste electricity!

Rubbish. I use far less energy that the average in teh UK. I do still have computers tho

I have attended the enquiries into the building of the Sizewell reactors, and been asked to leave more than once. Simple questions with direct answers requested.

1) Given that after building the station, ongoing the highest cost in production is the tranportation of generated power to the point of use, why are these reactors being built 70 miles from the urban conurbation that they serve (London). The answer given at the time was the proximity to a large water source and that availablity of land. Countered by so the Thames and the Battersea site aren’t technically suitable then? ……… Please will you leave?

2) Is it correct that the technology doesn’t currently exist to decommission and make these sites safe? Answer: (after some prevarication) It is anticpated that in 120 years time the technology will be available to do so, until that time the site will be managed safely. Response: Given that the site cannot be made safe for that long could I enquire as to why it is being built on the fastest eroding coast line in Europe whose average loss is in the order of 1 metre per annum? ………. Please will you leave?

Safety is a relative term. Not one of these reactors would get past normal scrutiny for a risk assessment in the workplace. The penalty for failure is so unimaginably high that the risk is just not tenable. so the question then comes back to are we prepared to risk it for the benefits we gain? Personally, the answer is no I’d rather look elsewhere, and try to use less energy as a solution to my energy needs.

I wouldn’t say using a computer is wasting electricity. I’d say leaving lights on when no one is in the room, leaving the heating on when you are out, leaving everything on standby, that is wasting electricity.

Who keeps saying nothing will explode and no radiation will escape, there’s been another explosion and people being told to stay inside for 30km around the site because of a radiation leak

Current production 4A, consumption 1A (it’s cloudy); I don’t see why I shouldn’t use a computer.

How? It’s easy. A combination of wind and solar power with pump storage using existing hydro stations will cover it. A tarif system such as the Italians use would also be necesssary to reduce the peaks in demand. Other legislation could be introduced to cut peaks such as limiting the wattage of things like immersion heaters or more drastically: limiting domestic electricity meters to 9A + 2A per occupant.

In my case annual production is 3300kWh and we use 2200kWh. The worst month is December with production of only 120kWh and consumption of 250kWh. I reckon the 12 000e I’ve inested in a fund to provide capital for mainly wind projects should produce enough to more than cover the December deficit.

Idustry and the public sector could perhaps achieve even greater savings given the waste I’ve seen in every institution I’ve worked in.

How? It’s easy. A combination of wind and solar power with pump storage using existing hydro stations will cover it.

In my case annual production is 3300kWh and we use 2200kWh. The worst month is December with production of only 120kWh and consumption of 250kWh

So despite having 50% annual overcapacity, you have a 130kWh gap in December. Given a very conservative 10 million UK households, that’s a 1.3TWh gap for the whole of the UK, even if they’re all as frugal as you. With 140GW of hydro in the whole of the EU, even if that lot was all converted to pumped storage (ignoring the infeasibility of that – there’s only actually 38GW of pumped storage), you’d need 9 hours of running at maximum capacity to cover the gap in needs of just the UK. Shame they typically only manage about half that at full capacity.

Of course I’m being pretty generous here, by ignoring the needs of industry and allowing you the use of solar generation, which is horrendously uneconomic on a large scale basis in the UK (I can only believe it makes sense at any scale due to grants).

Try again.

I reckon the 12 000e I’ve inested in a fund to provide capital for mainly wind projects should produce enough to more than cover the December deficit

So when you weren’t generating in December, presumably due to lack of wind, somebody else is supposed to magically get wind from somewhere to cover you?

That’s a 130kWh gap for the whole month. Or 4.3 kWh per day and given there are 24h in the day about .18kW instant.

On the basis of that consumption (180w instant per household of three) there’s enough hydro in Europe for the whole of Europe and then some.

There’s a lack of sun in December hense the low production, easily compensated by the wind investment.

300 000 000 x 180/3 = 18 000 000 000 = 18 GW.

So if European households reduce to my level of consumption in Decemeber there is curently two and a half times the necessary pump storage capacity.

I don’t know what your “Europe” refers to so I’ve used a population of 300 million.

You simply need the kind of commitment that went into producing weapons for WWII or the cold war

Hehe. That didn’t cost the country much, did it? Lolz.

How? It’s easy.

Of course. Silly rest-of-world!

How much d’you reckon it would cost to get every household generating their own power?

A combination of wind and solar power with pump storage using existing hydro stations will cover it.

Numbers, or it’s bolx.

Households could reduce consumption by 75%

Yeah, they could, but most are not going to are they! And how exactly would you force people to do this? The answer is you can’t.

Plus household use accounts for only about one third of the energy used in the UK anyway.

Well maths quite clearly isn’t your strong point, given two and a half times 18 isn’t 38. Of course if you’re going to look at instant generation capacity requirement, then you don’t take total energy demand and divide by the hours in the day – I mean you’re using more than 180W right now – pumped storage being designed to cope with these short term changes in demand rather than longer term lack of wind or sun, which is what you seem to think it’s going to do.

There’s a lack of sun in December hense the low production, easily compensated by the wind investment.

Oh, so you don’t actually have any wind generation capacity? But what does happen when there’s no sun and no wind?

At some point you might also want to address the power demands of industry rather than just domestic.

You’ve got the numbers now Molgrips, produce some of your own or admit I’m right.

Household account for a third, quite right. Apply the same philosophy to industry, street lighting, public buildings and so and you’ll soon be within the realms of what can be produced from renewables.

I too was sceptical when I went to see an energy advisor back in 05. I thought the estimates I was given were over optimistic. Experience has shown me that the savings from insulating were underestimated and so was the production of the solar panels. The technology works, works well and is viable.

I have a 3kW solar instalation, a solar hot water heater and have invested 12000e in a fund that finances wind power. So I do have more than enough total production capacity even in December, aracer. I am reliant on EDF for managing variations in my output through pump storage. Personal storage using batteries would be more polluting than using existing hydro infrastructure.

Why did they build them on the east coast and not the west coast? West coast being a built more sheltered etc?

DH

Sorry to contradict you but…

As accidents go, the one at Fukushima was predictable – earthquakes and tsunami tend to go together.

But the magnitude was far higher than the design standard. Standards will now have to change so plant survives stronger quakes and tsunami.

The Windscale fire was a result of a drive to produce Plutonium for the nuclear weapons programme hence an air cooled graphite moderated reactor with only a few filters preventing release of radioactive material into the environment.

It worked OK for Plutonium but the thermal modelling was flawed. When they tried to make Tritium for hydrogen bombs they exceed the safe temperature limits, which caused a fire. “Cockroft’s folly” filters, inadequate as they were, saved us from a much more serious disaster.

TMI was the result of a faulty meter reading

The PORV solenoid lamp worked fine, but the operators misunderstood what it meant. The PORV position gauge also worked fine but was not with the lamp, and hidden from view. There was no direct indication of coolant level. Coolant boiled away and exposed the rods leading to partial meltdown.

TMI has parallels here. Preoccupied operators failed to notice dangerously low coolant levels. Since the coolant level is so critical, why isn’t it measuredly directly and alarmed to death? I guess it’s because these plant are as ancient as TMI.

The usual response to: “the equipment doesn’t do X” is “the operators will do it manually”. But operators forget things, especially under stress. I’m not knocking the operators. If they hadn’t had the bright idea of using the fire suppression system to pump seawater into the cores, they would all have suffered meltdown.

So I do have more than enough total production capacity even in December

What happens when the wind doesn’t blow?

The water they pumped up the hill using my surplus is used for generation. Overcast periods with no wind don’t last long. Taking Europe as a whole they are almost inexistant.

You’ve got the numbers now

I’ve obviously missed your figures for total national energy production due to renewables, total pumped storage capacity, the needs of industry, etc. Maybe you could repeat them.

Compulsory hour long turbo sessions for each capable adult every night.

Micro generators built into every mattress sold.

Compulsory dynamo use.

Ban airconditioning AND deodorant.

Hat wearing compulsory on Tuesdays.

Should buy us a year or two….

Deaths per TWh for different power sources. The results shouldn’t surprise anyone with a brain.

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

Overcast periods with no wind don’t last long.

3 or 4 days isn’t long?

Taking Europe as a whole they are almost inexistant

I’m sure it will be a great relief to people that the lights will be on almost all the time. Of course there isn’t actually the grid capacity for us to get all our energy from Southern Europe for a few days, but surely you know that as you have all the figures to hand?

I too was sceptical when I went to see an energy advisor back in 05. I thought the estimates I was given were over optimistic. Experience has shown me that the savings from insulating were underestimated and so was the production of the solar panels. The technology works, works well and is viable

I am fully aware the benefits of home generation. I would love a setup like yours, but the problem is money. I haven’t got 12k euro lying around, and I suspect most folk don’t.

To get any large scale adoption would require subsidies and grants, and that money would have to come from somewhere. The Govt could in theory but won’t be able to for a while yet.

Plus I am sceptial that pump storage would provide enough power storage for the whole country to cover gaps in wind coverage.