Nuclear Power

[watercooled]

The reactors in Japan did very well in the natural disasters, The only lesson they could learn from that is to try and build new ones in areas less at risk of that kind of disaster.

It wasn't anything that wasn't already known though; a BWR which needs to be actively cooled to get rid of the decay heat had diesel generators near to the ground near the pacific ring of fire. Even something simple like moving the generators higher up could have made things far less significant. Instead, it's obviously considered not that important so the public see another 'nuclear explosion at power plant', further damaging its reputation. When public opinion is already as low as it is you need to be so sure even technically minor accidents (but possibly still frightening to the public) are considered and planned for; a steam explosion at a coal plant might make a small column in a newspaper, a secondary coolant steam explosion at a nuclear plant is pretty much guaranteed to make headline news a few times in a row with a nice 'nuclear plant explosion' title.

I'm not for one minute saying it's anyone's fault, but it's best to cover as many scenarios as possible, with redundancy. E.g. there were flood barriers at Fukushima, but the diesel generators could have still been placed higher up, just-in-case.

[Knoxville]

Simple question, forget wind turbines, forget solar power... Why can't we go tidal?

Especially as an island nation, why aren't places like Bridlington hot spots for a clean, extremely predictable source of power?

Its all well and good extolling the virtues of nuclear power but eventually we've got to bury all that spent fuel right? Unless I've not been paying attention for so long that words like Half Life don't matter. Even huge underground storage facilities like the one in Onkalo which was built as a very long term solution will be full in less than 100 years at the current rate at which waste is generated by Finlands nuclear plants, and currently they only account for around a quarter of the power produced in the country.

If one were to employ Daily Mail maths you're talking about a disposal site with maybe what? A 25 year life span if the whole country had to go nuclear? Of course it'd be nowhere near that short but it begs questions in my opinion. Especially when the cost for the disposal site spirals to close to double that of a brand new nuclear power station.

[Sputnik]

I'm surprised that the Japanese made such a mistake as they generally engineer things so well.

[watercooled]

Simple question, forget wind turbines, forget solar power... Why can't we go tidal?

It's not easy to get an awful lot of power from tidal, and it may be predictable but it's not constant.

Its all well and good extolling the virtues of nuclear power but eventually we've got to bury all that spent fuel right? Unless I've not been paying attention for so long that words like Half Life don't matter. Even huge underground storage facilities like the one in Onkalo which was built as a very long term solution will be full in less than 100 years at the current rate at which waste is generated by Finlands nuclear plants, and currently they only account for around a quarter of the power produced in the country.

If one were to employ Daily Mail maths you're talking about a disposal site with maybe what? A 25 year life span if the whole country had to go nuclear? Of course it'd be nowhere near that short but it begs questions in my opinion. Especially when the cost for the disposal site spirals to close to double that of a brand new nuclear power station.

It's been brushed upon earlier in this thread but firstly, there's essentially no nuclear waste from fusion. The main product is helium which is completely harmless and possibly even a bonus considering how much of the limited substance is being wasted in balloons and such. You also get a bit of tritium but it has a very short half life and when you consider how much radiation is released in to the air by coal-fired plants, it's little cause for concern. The main problem is the containment structure which would be radioactive after operation, but again it wouldn't be for long and it's not highly radioactive, much like some medical equipment.

As for fission, waste storage was covered earlier on. However, new reactor designs can use 'used', or reprocessed, fuel from other plants keeping it out of storage. But either way the amount of waste you get from nuclear is negligible compared to fossil fuels.

Cost is a problem, but it is factored into the cost of new plants - nuclear is already relatively very cheap and it would be cheaper again if waste wasn't a problem.

There are also some experimental systems (will post a link if I can find some info) which basically irradiate waste to 'burn off' the residual radiation.

[Knoxville]

It's not easy to split atoms either though is it.. But we managed that It might not be the solution to everyones problems but any natural force that's always going to be there and transports as much as two million tons of stone and earth from just a few miles of coastline per year strikes me as worth harvesting while we keep cracking at fusion power. We've been dragging it out and throwing a few quid at it and then putting it back in cupboard again so we can spend more on wars for fifty some odd years but we've never made it work for more than a second or so unless I'm mistaken?

Fusion's a fantastic solution to a global energy crisis. Relatively cheap, low waste, abundant fuel I get all of that, but it doesn't work and might not for another fifty years. We can't bet on a horse that isn't born yet, at least I'd rather not. If fossil fuels run out as predicted and fusion doesn't work by then the world has to go either the route of natural (unreliable) energy sources or for old school (dirty and costly) fission power neither of which is lacking in cons, why not attempt to harness a force of nature we have a pretty good grasp of that wipes a city off the map almost every year in the meantime?

I may be speaking out of turn but governments seem to throw a fair whack of cash at alternative power but there's never really as much brain power at work on that side of the fence as there are men in cardigans and clogs with composting toilets back at home, erecting windmills and making things out of hemp. Scientists say harnessing nature is too difficult, that it's too unreliable.. I'm sure there was a time when words like that, along with the word dangerous were thrown at the idea of nuclear power but we got some clever blokes together in a metaphorical shed and made it work. Why don't we ever seem to put that much brain power behind something that can't also be used to blow things up?

[BobF64]

I may be speaking out of turn but governments seem to throw a fair whack of cash at alternative power

Because the government made stupid promises it shouldnt have, but whats new there?

[Macman]

There is a version of risk called nuclear risk - where you get to nuke territories and they remain radioactive, depleting the strength of armies put on them. Perfect fodder for any budding Dr Evil's with world domination at heart.


ps any chance you can edit your post out of sensitivity for those of us who find blasphemy a bit offensive?

To be honest, if anyone was take offense then that's their choice. I was simply adding humour due to the amount of folk who have knowledge in the Nuclear aspect. My thread, take it with a pinch of salt.

No offence intended.

[TheAnimus]

Case in point. I don't even know what they were hoping to achieve. Hope you're enjoying your higher electricity bills from importing nuclear energy from France, retards.

Yes, the joys of protesters, they think they are 'right' even if they go against democratic principles, or what the experts say.

What amazes me is that they can be seen trying to destabalise the railway embankment, truely shocking!

[watercooled]

It's not easy to split atoms either though is it.. But we managed that It might not be the solution to everyones problems but any natural force that's always going to be there and transports as much as two million tons of stone and earth from just a few miles of coastline per year strikes me as worth harvesting while we keep cracking at fusion power. We've been dragging it out and throwing a few quid at it and then putting it back in cupboard again so we can spend more on wars for fifty some odd years but we've never made it work for more than a second or so unless I'm mistaken?

Good point, but unless you had a global power grid you couldn't get a constant electricity supply from tidal. It makes people feel better when you have a dial to turn up rather than just crossing fingers you'll get power when it's needed.

You mean we've never had tidal working for long? I'm assuming you mean fusion but the newer Tokamok reactors can sustain reactions for minutes and produce power, just they consume more than they produce at the moment. It's definitely improving though.

Fusion's a fantastic solution to a global energy crisis. Relatively cheap, low waste, abundant fuel I get all of that, but it doesn't work and might not for another fifty years. We can't bet on a horse that isn't born yet, at least I'd rather not. If fossil fuels run out as predicted and fusion doesn't work by then the world has to go either the route of natural (unreliable) energy sources or for old school (dirty and costly) fission power neither of which is lacking in cons, why not attempt to harness a force of nature we have a pretty good grasp of that wipes a city off the map almost every year in the meantime?

Renewable energy isn't all that 'green', it takes up lots of room due to the low generation density and a lot of it involves destroying a certain amount of land. Neither is fission dirty and costly, quite the opposite in fact; you get very little waste and it's far cheaper than wind power, for instance. Sure, the fuel is free for renewable energy but the cost of building, maintenance and the need for so much reserve due to its unreliable nature make it very expensive; the UK has something like 4000MW installed wind power capacity yet the yearly average seems to be less than 1000MW, at which point the normal plants have to pick up the slack anyway - so you're paying for the energy twice essentially. It kind of works to add to the grid but in reality you still need to have the capability to reach peak demand with existing plants. Bear in mind a single modern fission reactor can be expected to produce >1000MWe.

I may be speaking out of turn but governments seem to throw a fair whack of cash at alternative power but there's never really as much brain power at work on that side of the fence as there are men in cardigans and clogs with composting toilets back at home, erecting windmills and making things out of hemp. Scientists say harnessing nature is too difficult, that it's too unreliable.. I'm sure there was a time when words like that, along with the word dangerous were thrown at the idea of nuclear power but we got some clever blokes together in a metaphorical shed and made it work. Why don't we ever seem to put that much brain power behind something that can't also be used to blow things up?

As the saying goes, some of the best advancements in technology are made in times of war. However, fusion power has very little relation (expect for the core physics) to weapons, about the only useful thing for weapon design is tritium but since that's plentiful anyway there's no need to make fusion power work in order to make it.

[Fraz]

Don't know if it's been covered yet, but another possible (partial) solution to the nuclear waste issues from fission is to simply fire a reasonably decent particle beam at it. Basically, the idea is to turn all the long half-life stuff into shorter half-life stuff. You still end up with radioactive waste, but it becomes non-radioactive on timescales much easier to deal with.

This is an active area of research, as I understand it, and people are looking into the practicalities of actually processing large amounts of waste in this way.

[watercooled]

Don't know if it's been covered yet, but another possible (partial) solution to the nuclear waste issues from fission is to simply fire a reasonably decent particle beam at it. Basically, the idea is to turn all the long half-life stuff into shorter half-life stuff. You still end up with radioactive waste, but it becomes non-radioactive on timescales much easier to deal with.

This is an active area of research, as I understand it, and people are looking into the practicalities of actually processing large amounts of waste in this way.

Yeah that's what I was referring to earlier but I can't find the article I had in mind. Or was it a video on Youtube?

[Knoxville]

Good point, but unless you had a global power grid you couldn't get a constant electricity supply from tidal. It makes people feel better when you have a dial to turn up rather than just crossing fingers you'll get power when it's needed.

I know we've never had tidal working for long, it seems I was a little out of touch with some of the advancements that have obviously been made with fusion though.

So we've gone to reactions that can be stabilised for upwards of a minute instead of seconds and they still use more power than they produce. I know it sounds like I'm mocking it a bit, I'm not, that is progress but is it happening in the kind of time frame we need it to? As, well, as a species frankly because once fossil fuel reserves deplete everything that's made the huge increase in the earths population since the industrial revolution possible and sustainable pretty much dissapears..

Renewable energy isn't all that 'green', it takes up lots of room due to the low generation density and a lot of it involves destroying a certain amount of land. Neither is fission dirty and costly, quite the opposite in fact; you get very little waste and it's far cheaper than wind power, for instance. Sure, the fuel is free for renewable energy but the cost of building, maintenance and the need for so much reserve due to its unreliable nature make it very expensive; the UK has something like 4000MW installed wind power capacity yet the yearly average seems to be less than 1000MW, at which point the normal plants have to pick up the slack anyway - so you're paying for the energy twice essentially. It kind of works to add to the grid but in reality you still need to have the capability to reach peak demand with existing plants. Bear in mind a single modern fission reactor can be expected to produce >1000MWe.

In its current form I don't disagree. I remember reading about a bunch of guys out in the desert somewhere in the states trying to distill petrol from pretty much thin air and sunlight and it all sounds really impressive until you reach the "How many gallons do we get per square mile of huge reflector arrays?" question. I can't help but wonder how much better our ideas and solutions in the area of "renewable" energy would be though if the scientific community didn't turn its back and scoff at the idea and was actually forced to and funded well enough to knuckle down, instead of throwing a few token million at windmills to keep the Green Party happy every year.

Fission sounds ok once you get past the fear factor brought on by events like Chernobyl, Fukushima etc. that stain its reputation for the general public but I still see disposal of waste in the event fusion power doesn't come through in time as an issue. The Onkalo disposal site I mentioned earlier is nearly 6km long and 500 metres deep and that's enough to serve Finland (one of the countries with the highest number of nuclear plants in Europe if memory serves) for 100 hundred years with only 20 something percent of their grid reliant on nuclear power. Worst case scenario, fusion isn't viable when fossil fuels go bye bye, that's a lot of disposal sites and a huge cost not just in construction but maintenance and space occupied. These are structures we're expecting to last hundreds of thousands of years yet we as a species have never built anything older than the pyramids. I'm not a structural engineer but I know guesswork gets you into trouble more often than not and it costs too. The Russians poured millions of tons of concrete over reactor number four and twenty years later it's already not good enough and we've found repair work in such a hostile environment isn't easy or cheap.

Yes its a different scenario and we've learned a lot more since, we've probably learned more from Chernobyl itself but I think we're being optimistic at best with some of our projections when it comes to waste storage if the worst happens.

As the saying goes, some of the best advancements in technology are made in times of war. However, fusion power has very little relation (expect for the core physics) to weapons, about the only useful thing for weapon design is tritium but since that's plentiful anyway there's no need to make fusion power work in order to make it.

We do indeed, that that is unfortunately the case irks me but that's a different debate entirely My knowledge of the actual raw science of a commercial fusion reactor and its possible applications is basic at best. How happy are we going to be to let just any developing nation get their hands on that tech if and when we perfect it though? As common place as fission reactors are we're still pretty cagey about who can and can't have a nuclear research program.

In that case, diplomatically speaking at least it doesn't really matter how easy it would be to reverse engineer a fusion reactor into the basis for a weapons program, just how easy it would be to make the argument that you can.

[watercooled]

Fission sounds ok once you get past the fear factor brought on by events like Chernobyl, Fukushima etc. that stain its reputation for the general public but I still see disposal of waste in the event fusion power doesn't come through in time as an issue. The Onkalo disposal site I mentioned earlier is nearly 6km long and 500 metres deep and that's enough to serve Finland (one of the countries with the highest number of nuclear plants in Europe if memory serves) for 100 hundred years with only 20 something percent of their grid reliant on nuclear power. Worst case scenario, fusion isn't viable when fossil fuels go bye bye, that's a lot of disposal sites and a huge cost not just in construction but maintenance and space occupied. These are structures we're expecting to last hundreds of thousands of years yet we as a species have never built anything older than the pyramids. I'm not a structural engineer but I know guesswork gets you into trouble more often than not and it costs too. The Russians poured millions of tons of concrete over reactor number four and twenty years later it's already not good enough and we've found repair work in such a hostile environment isn't easy or cheap.

Yes its a different scenario and we've learned a lot more since, we've probably learned more from Chernobyl itself but I think we're being optimistic at best with some of our projections when it comes to waste storage if the worst happens.

We're not expecting them to last hundreds of thousands of years though; lots of work is being done on properly 'burning off' the excess radiation so you end up with something less radioactive than coal ash, like what Fraz mentioned above. The waste storage sites aren't these big concrete tombs sealed off for all eternity they're perceived to be.

Chernobyl was never designed for long-term storage of spent nuclear fuel, and the fact what's left has melted into a big chunk doesn't really make it easy to get to or clean up. Prevention is much easier than cure, especially when the cure involves building a complex, airtight structure in less than ideal working conditions.

We do indeed, that that is unfortunately the case irks me but that's a different debate entirely My knowledge of the actual raw science of a commercial fusion reactor and its possible applications is basic at best. How happy are we going to be to let just any developing nation get their hands on that tech if and when we perfect it though? As common place as fission reactors are we're still pretty cagey about who can and can't have a nuclear research program.

In that case, diplomatically speaking at least it doesn't really matter how easy it would be to reverse engineer a fusion reactor into the basis for a weapons program, just how easy it would be to make the argument that you can.

Two completely different scenarios.

With a uranium fuelled fission reactor, some of the products of the reaction are useful in weapon manufacture, plutonium for instance.

However, sustaining a fusion reaction is considerably harder than producing a weapon; any country capable of sustaining a fusion reaction would almost certainly be capable of making weapons. And as I said, the products from a fusion power plant wouldn't help a country make weapons anyway. Slamming atoms together to get a fusion reaction is relatively simple if you have the conditions produced by a fission bomb exploding - a H-bomb still needs a fission 'primary' to trigger the fusion 'secondary'.

[melon]

It's not easy to get an awful lot of power from tidal, and it may be predictable but it's not constant.



It's been brushed upon earlier in this thread but firstly, there's essentially no nuclear waste from fusion. The main product is helium which is completely harmless and possibly even a bonus considering how much of the limited substance is being wasted in balloons and such. You also get a bit of tritium but it has a very short half life and when you consider how much radiation is released in to the air by coal-fired plants, it's little cause for concern. The main problem is the containment structure which would be radioactive after operation, but again it wouldn't be for long and it's not highly radioactive, much like some medical equipment.

As for fission, waste storage was covered earlier on. However, new reactor designs can use 'used', or reprocessed, fuel from other plants keeping it out of storage. But either way the amount of waste you get from nuclear is negligible compared to fossil fuels.

Cost is a problem, but it is factored into the cost of new plants - nuclear is already relatively very cheap and it would be cheaper again if waste wasn't a problem.

There are also some experimental systems (will post a link if I can find some info) which basically irradiate waste to 'burn off' the residual radiation.

I agree with nuclear over fossil fuels any day, one reason being its not renewable , the other is where that depletion leads - namely wars.. global warming etc etc

m

[Lanky123]

So we've gone to reactions that can be stabilised for upwards of a minute instead of seconds and they still use more power than they produce. I know it sounds like I'm mocking it a bit, I'm not, that is progress but is it happening in the kind of time frame we need it to?

Whilst we haven't managed to achieve breakeven or sustain fusion for very long, that isn't actually the main problem as I understand it. We understand enough about how the plasma behaves under magnetic confinement at ~100 million Kelvin to know that it will work, we just need to scale up the design (ie - build ITER). The main problem is more of a materials science - 80% of the energy produced when deuterium and tritium fuse is carried by a neutron (the other 20% by a helium-4 nucleus). As neutrons have no charge they are not confined by the humungous magnetic fields and just whiz off out of the plasma chamber. This presents two problems:

1. We need to harvest that energy...and that is much harder with neutrons than it would be with charged particles. Surrounding the reactor in a lithium blanket (good at absorbing neutrons) is one possible solution. You can actually breed tritium in this way to feed back into the reactor as fuel (handy as tritium has a half life of about 12 years so doesn't occur naturally in abundance). However, try and efficiently extract the heat to produce power, cycle out the tritium produced (and preferably helium-4 which is also a by product here) and replenish the lithium used all at once.

Keep in mind that we are also quite fond of using lithium in batteries and have a limited supply, if reasonably abundant for the moment. As a back of the envelope calculation - if we used all known lithium reserves for fusion we could power the entire world (at current consumption levels) for about 200 years. Deuterium-deuterium fusion is also possible (We get the deuterium from seawater so no problems there) but is an order of magnitude or so harder to achieve in terms of confinement.

2. Neutrons that energetic are not good for the materials they go through - the nuclei they hit can scatter them (absorbing some of the energy in the process) or absorb the neutron itself, creating different, often unstable isotopes. This means materials surrounding the reactor will become radioactive over time and will also become brittle. These materials will therefore have to be chosen *very* carefully, with a balance of properties in mind. Ideally they should be very resilient to the degradation and any radioactive material produced from neutron activation should be low level. This process happens in fission reactors as well but the neutrons aren't as energetic.


As an upshot - don't bank of fusion reactors suddenly providing cheap energy when they do eventually arrive. Most likely the first wave will have teething problems, be very expensive to build, and probably require refurbishment and various bits replacing now and again. Fusion is the future and deserves a lot more funding than it gets...but we need fission reactors for now (preferably breeder reactors to increase fuel efficiency and reduce waste). Quite frankly even when fusion arrives fission will probably be cheaper for a while...money matters, and I don't see that changing any time soon.

[Knoxville]

I feel.. Well informed guys If not entirely convinced

The reason I'm not entirely convinced is because of a poxy little article in The Metro a long time ago that made me go read up on a few things. Posiva, the leading company that builds these tombs to house our waste (and are currently building the one I mentioned previously) go so deep into the research, design and construction of these places it fascinated me. They really do expect these places to last 200,000 years and beyond. If you go through the research they do for every site it is astounding, I'm talking ground water salinity projections thousands of years in advance, estimated sea levels post the next ice age and investigations into the plausiblilty of glaciers formed during that time causing earthquakes as they begin to thaw. Hand on heart, they talk about cosmic dust at one point in their literature.

They do quite literally build these things, fill them, rip up the buildings at ground level and move on. To the point where one of their biggest concerns now is how we mark them in case future (uninformed) generations stumble onto one of these sites and start digging themselves a well, which is also funnily enough a scenario they've researched in great depth and discuss in their documentation.

We might be developing ways to burn off the excess radiation from our waste and sanitise it as much as possible (for want of a better word) but we've still got stuff sat around in "cooling off" stages we can't process for another twenty years before we even start on the waste we're producing now. Couple that with the fact the longevity of the disposal sites we're building now is negotiable and based on the best guess work possible, but still guesswork... I just don't like it.

For everything we think we know, I think that in the grand scheme of things when it comes to harnessing the atom we're still only just about at the same stage as a kid that only barely understands his first chemistry set and that's the stage that usually costs the street most of its household pets. I hope it never happens and we live in a world where fusion does what it says on the tin - provides lovely clean power, gives nobody an extra nuclear arsenal and solves the impending global energy crisis before it starts but; I have my doubts and I'd still like to see more brain power put into "greener" solutions. After all when we put our minds to it we can do so much, why continue to put all our eggs in one basket when the clock is genuinely ticking?