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nuclear

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  • Registered Users Posts: 5,533 ✭✭✭Jester252


    Macha wrote: »
    Basically, nuclear has very slow ramp up and ramp down rates, meaning the plants are slow to start up and slow to turn off relative to other generation technologies. Because of this nuclear works well as baseline load, ie you keep the plants running as long as possible without shutting the plants down.

    Wind, and a lot of other renewables, on the other hand have very fast ramp up and ramp down rates, which means they can be turned on and off very quickly (sometimes when you don't necessarily want them to..).

    If you have nuclear plants running all the time, it's inefficient because demand curves vary throughout the day (peak is normally 5-7pm and bottom is 3-5am). At the same time, wind generation can fluctuate wildly during the day, regardless of the demand.

    Put the two together and you easily get a situation where wind generators are forced to stop generating (curtailment), which makes wind uneconomical. At the same time, if nuclear were asked to be as flexible as wind, it simply wouldn't be technologically possible.

    They work together on a limited scale at the moment across Europe but you're starting to have situations where, for example, Germany is exporting power into Europe at times of high winds/strong sunshine and this is messing with France's steady-state power system based on nuclear.

    But that is the major problem with having renewable as the major power source. Its okay as a minor source. Power grids are based off a stable base load which a lot of controls will be needed to achieve this. As you said with wind peak during the night and drops during the day the opposite to our power usage. If renewable are the major power source we will have to import power from the UK (Nuclear power) during the day and sell it at night when we don't need it which is when they don't need it so more or less it will go to waste.

    This problem has be tried to be fixed with a water pump storage. As it pump water up to a man made lake at night with the excess power and run it down through a hydro power plant during the day. This has its own problem from a development point of view.


  • Registered Users Posts: 5,533 ✭✭✭Jester252


    djpbarry wrote: »
    The point is people are forever coming on these threads promoting nuclear for all, but when it is pointed out to them that there may not be enough (easily extractable) uranium to go 'round, they all shout "Hey, look! Thorium!". Which is all well and good, except that, as I said, it's not actually in use anywhere.

    This thread was set up by the op to explore the nuclear option. As in see what can be done. You are will to throw thorium out as there is not a reactor open for commercial use.


  • Moderators, Science, Health & Environment Moderators Posts: 6,376 Mod ✭✭✭✭Macha


    Jester252 wrote: »
    But that is the major problem with having renewable as the major power source. Its okay as a minor source. Power grids are based off a stable base load which a lot of controls will be needed to achieve this. As you said with wind peak during the night and drops during the day the opposite to our power usage. If renewable are the major power source we will have to import power from the UK (Nuclear power) during the day and sell it at night when we don't need it which is when they don't need it so more or less it will go to waste.

    This problem has be tried to be fixed with a water pump storage. As it pump water up to a man made lake at night with the excess power and run it down through a hydro power plant during the day. This has its own problem from a development point of view.

    Or you could flip it and say the major problem is having all these inflexible base-load hogging technologies as our major power source. Nuclear is very inflexible and can't ramp up or down to match demand.

    Yes our existing power grids have been designed to accommodate baseload plants but our grids are old and need to be replaced and renewed. We can either do it in a way that apes the old way, or we can build dynamic grids that can facilitate flexible sources like renewables and build out on storage.

    As I mentioned in an earlier post, Europe's hydro potential has been largely exhausted but linking in existing hydro with RES is a different story altogether.


  • Registered Users Posts: 804 ✭✭✭Chloe Pink


    Macha wrote: »
    Well, demand side management is something else but I know what you mean.

    In theory, the answer is yes but:
    a) sufficient nuclear capacity won't get built in time to help our emissions peak before 2020;
    b) we have other options.

    Like lots of fossil fuels, a little substituted with tidal and biomass; and some additional capacity from wind and solar?

    Or like lots of (nuclear and fossil fuels), a little substituted with tidal and biomass; and some additional capacity from wind and solar?

    Are there other options?


  • Moderators, Science, Health & Environment Moderators Posts: 6,376 Mod ✭✭✭✭Macha


    Chloe Pink wrote: »
    Like lots of fossil fuels, a little substituted with tidal and biomass; and some additional capacity from wind and solar?

    Or like lots of (nuclear and fossil fuels), a little substituted with tidal and biomass; and some additional capacity from wind and solar?

    Are there other options?
    This is why I don't want to debate this issue with you.

    You fail to acknowledge the potential of renewables energy sources, ignore the massive subsidies (existing and historical) and imbalances in the current power grid and market design in favour of large incumbents like FF & nuclear and don't see any of the issue with nuclear technology, such as ever-increasing project costs and delays, an upward-spiralling technology cost-curve (I've never seen a nuclear learning curve that goes down), the need for massive state investment in what is effectively a mature technology and the fact that it just won't be built without state aid. Plus the fact that only the state can insure against the risks of nuclear. You tell me who is bailing out Tepco to the tune of €13 billion. Hint: not a private insurance company.

    And then came the bats. So I'm done.


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  • Registered Users Posts: 5,533 ✭✭✭Jester252


    Macha wrote: »
    Or you could flip it and say the major problem is having all these inflexible base-load hogging technologies as our major power source. Nuclear is very inflexible and can't ramp up or down to match demand.

    Yes our existing power grids have been designed to accommodate baseload plants but our grids are old and need to be replaced and renewed. We can either do it in a way that apes the old way, or we can build dynamic grids that can facilitate flexible sources like renewables and build out on storage.

    As I mentioned in an earlier post, Europe's hydro potential has been largely exhausted but linking in existing hydro with RES is a different story altogether.
    What you are saying is been done and is currently in place but a base load is needed.
    one of the biggest threats to the gird is half-time in the all-Ireland. Why because the kettle goes on in every house and the base load needs to be increased so the grid doesn't crash.
    As for Watts/M2 Wind or renewable is currently too low.
    Also even of we had a flexible grid the problem that more wind during less demand is still there. Not to mention that if the wind is too fast or too slow the wind turbines are turned off to protect them or not turn into a motor.
    The HVDC line from Dublin to the UK will be used for Ireland to import energy from the UK.
    Granted that is the first step on the ladder for a smart grid where the north of Europe supply's most of the wind and the south supply's most of the solar.
    Solar energy during the day. Wind at night.
    But renewable are very unstable in terms of power supply. We will need a stable source of energy one that can give power 24/7 without fail


  • Registered Users Posts: 126 ✭✭CajunPenguin


    GarIT wrote: »
    After what happened in Chernobyl and then what nearly could have happened in Japan there is no way I would support it. I'm all for advancements but not something that can cause as much damage as nuclear fission. If someday fusion became a workable idea I would consider it as I've read its not as dangerous.
    That's the typical response from people who don't understand it. Thorium is basically as risky as coal or oil, well maybe not coal but the benefits of thorium definitely outweigh the risks
    1. Thorium is cheap and readily available even here in Ireland
    2. It isn't very explosive (The reason Chernobyl and Fukushima were dangerous was because they use Uranium, which is used because the leftovers can be used to make plutonium and weaponize the materials, and the habit stuck)
    The only disadvantages are the waste (which in my opinion isn't worth it) which is minimal and the smoke and everything that already comes with fossil fuels


  • Registered Users Posts: 12,775 ✭✭✭✭Gbear


    That's the typical response from people who don't understand it. Thorium is basically as risky as coal or oil, well maybe not coal but the benefits of thorium definitely outweigh the risks
    1. Thorium is cheap and readily available even here in Ireland
    2. It isn't very explosive (The reason Chernobyl and Fukushima were dangerous was because they use Uranium, which is used because the leftovers can be used to make plutonium and weaponize the materials, and the habit stuck)
    The only disadvantages are the waste (which in my opinion isn't worth it) which is minimal and the smoke and everything that already comes with fossil fuels

    I'm pretty sure that the explosiveness of uranium has nothing to do with it.
    Chernobyl "exploded" due to, I think, superheated steam expanding very rapidly.
    The uranium in nuclear reactors is not the same stuff as in bombs - less U235. Otherwise a runaway reaction would result in an explosion wheras at a reactor it involves the uranium getting really really hot.

    And no smoke is released from nuclear power plants. They release steam.

    I think I saw a TED talk mentioning that Bill Gates' futuristic technology investment company was working on thorium reactors. I shall have a look after my Spanish exam. :)


  • Moderators, Science, Health & Environment Moderators Posts: 6,376 Mod ✭✭✭✭Macha


    Jester252 wrote: »
    What you are saying is been done and is currently in place but a base load is needed.
    one of the biggest threats to the gird is half-time in the all-Ireland. Why because the kettle goes on in every house and the base load needs to be increased so the grid doesn't crash.
    As for Watts/M2 Wind or renewable is currently too low.
    Also even of we had a flexible grid the problem that more wind during less demand is still there. Not to mention that if the wind is too fast or too slow the wind turbines are turned off to protect them or not turn into a motor.
    The HVDC line from Dublin to the UK will be used for Ireland to import energy from the UK.
    Granted that is the first step on the ladder for a smart grid where the north of Europe supply's most of the wind and the south supply's most of the solar.
    Solar energy during the day. Wind at night.
    But renewable are very unstable in terms of power supply. We will need a stable source of energy one that can give power 24/7 without fail

    Not hardly. Europe has barely scratched the surface of its renewables potential. I appreciate the issues with demand vs generation but as I've mentioned, these also exist with baseload as it is not flexible enough to follow demand curves, and definitely not to deal with the half-time issue you seem very worried about.

    The flexible grid would not only factilitate the connection of more renewables but more interconnection and storage, plus demand-side management. Interconnectors are rarely only used one-way. The British government is very interested in supporting Ireland's renewables industry with a few to importing.

    Renewables are not unstable, or no more so than any other source. There is no energy source that can't fail.


  • Registered Users Posts: 13,104 ✭✭✭✭djpbarry


    Jester252 wrote: »
    This thread was set up by the op to explore the nuclear option. As in see what can be done. You are will to throw thorium out as there is not a reactor open for commercial use.
    I’m not dismissing thorium-based reactors, I’m just pointing out that it’s still a highly experimental technology. People often fail to acknowledge this while simultaneously dismissing wind power (look at the OP) on the basis of, for example, variable output – but there are a whole bunch of experimental energy storage technologies that could potentially alleviate this. Take this remarkably simple approach, for example:
    http://www.newscientist.com/blogs/onepercent/2012/04/green-machine-undersea-air-bag.html

    All I’m looking for here is a little consistency.


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  • Registered Users Posts: 804 ✭✭✭Chloe Pink


    Macha wrote: »
    You fail to acknowledge the potential of renewables energy sources, ignore the massive subsidies (existing and historical) and imbalances in the current power grid and market design in favour of large incumbents like FF & nuclear and don't see any of the issue with nuclear technology, such as ever-increasing project costs and delays, an upward-spiralling technology cost-curve (I've never seen a nuclear learning curve that goes down), the need for massive state investment in what is effectively a mature technology and the fact that it just won't be built without state aid. Plus the fact that only the state can insure against the risks of nuclear. You tell me who is bailing out Tepco to the tune of €13 billion. Hint: not a private insurance company.
    I asked a straight forward question paving the way for you to explain how renewables could be used - it's up to you as to whether or not you respond but please don't claim knowledge of me that I haven't expressed; it is not only presumptious but you attribute me with views I do not hold.


  • Moderators, Science, Health & Environment Moderators Posts: 6,376 Mod ✭✭✭✭Macha


    [mod]This thread isn't about renewables. Please get back on topic.[/mod]


  • Registered Users Posts: 5,533 ✭✭✭Jester252


    Macha wrote: »
    Not hardly. Europe has barely scratched the surface of its renewables potential. I appreciate the issues with demand vs generation but as I've mentioned, these also exist with baseload as it is not flexible enough to follow demand curves, and definitely not to deal with the half-time issue you seem very worried about.

    The flexible grid would not only factilitate the connection of more renewables but more interconnection and storage, plus demand-side management. Interconnectors are rarely only used one-way. The British government is very interested in supporting Ireland's renewables industry with a few to importing.

    Renewables are not unstable, or no more so than any other source. There is no energy source that can't fail.

    The grid is very flexible at the moment. Turbines can be added and removed from the grid with little effort. But the base load is a constant supply of energy to use. It is needed. I have no problems with renewable the tech is there and anybody can build and understand it. But it is very low 1 wind turbine = 1MW = 650homes a year. As I said before wind is very intermittent so for a grid like this to be built would require other sources like hydro, wave, tidal,solar and biomass. Biomass and hydro are the only ones that are stable currently and Ireland has kinda taped into its only source of hydro the Shannon. So it this grid will need a lot of little power station ran by private people and different companies all over the country. Doing this will involve a lot of planing permission and red tape. Most will be stopped due to NIMBY syndrome (lot of BS when to a hydro and a wind farm on a college trip no noise at all). So plant will be pushed out into rural areas increasing the cost.
    I would love to see Ireland and the rest of the world to be 100% renewable but that not going to happen so I will like a look into nuclear power. I only posted in this thread due to the straight NO response of some posters when the op was looking for a debate and some of the answer contained end of the world stuff. Nuclear and renewable should be an option but not the answer or any improve in power generation will stop


  • Registered Users Posts: 5,533 ✭✭✭Jester252


    djpbarry wrote: »
    I’m not dismissing thorium-based reactors, I’m just pointing out that it’s still a highly experimental technology. People often fail to acknowledge this while simultaneously dismissing wind power (look at the OP) on the basis of, for example, variable output – but there are a whole bunch of experimental energy storage technologies that could potentially alleviate this. Take this remarkably simple approach, for example:
    http://www.newscientist.com/blogs/onepercent/2012/04/green-machine-undersea-air-bag.html

    All I’m looking for here is a little consistency.
    I like it its a bit like how wave power works

    http://www.sustainability.ie/pumpedstoragemyth.html
    Have you heard about this


  • Registered Users Posts: 8,410 ✭✭✭Markcheese


    Macha wrote: »
    Jester252 wrote: »
    why wont they work together?

    Basically, nuclear has very slow ramp up and ramp down rates, meaning the plants are slow to start up and slow to turn off relative to other generation technologies. Because of this nuclear works well as baseline load, ie you keep the plants running as long as possible without shutting the plants down.

    Wind, and a lot of other renewables, on the other hand have very fast ramp up and ramp down rates, which means they can be turned on and off very quickly (sometimes when you don't necessarily want them to..).

    If you have nuclear plants running all the time, it's inefficient because demand curves vary throughout the day (peak is normally 5-7pm and bottom is 3-5am). At the same time, wind generation can fluctuate wildly during the day, regardless of the demand.

    Put the two together and you easily get a situation where wind generators are forced to stop generating (curtailment), which makes wind uneconomical. At the same time, if nuclear were asked to be as flexible as wind, it simply wouldn't be technologically possible.

    They work together on a limited scale at the moment across Europe but you're starting to have situations where, for example, Germany is exporting power into Europe at times of high winds/strong sunshine and this is messing with France's steady-state power system based on nuclear.


    Which goes to show that nuclear would work brilliantly with pumped hydro storage( spirit of Ireland scale) . Letting nuclear work more efficiently by absorbing peaks in supply and providing power for demand spikes....
    I know this would mean Ireland would be part of a nuclear industry, if we went down this route, but without any reactors .... And providing industry in the west....

    Slava ukraini 🇺🇦



  • Moderators, Science, Health & Environment Moderators Posts: 6,376 Mod ✭✭✭✭Macha


    Markcheese wrote: »
    Which goes to show that nuclear would work brilliantly with pumped hydro storage( spirit of Ireland scale) . Letting nuclear work more efficiently by absorbing peaks in supply and providing power for demand spikes....
    I know this would mean Ireland would be part of a nuclear industry, if we went down this route, but without any reactors .... And providing industry in the west....
    Eirgrid has already said that SoI is not a runner. We have no more hydro potential and have exploited what little we have.


  • Closed Accounts Posts: 256 ✭✭Statistician


    djpbarry wrote: »
    But nothing really happened in Japan? The reactor was hit by a massive earthquake and tsunami and it still remained relatively intact – how is that anything other than an advert for the safety of nuclear power?
    So it’s ok to import non-“green” energy, but not to produce it in Ireland?

    'Nothing really happened in Japan'?

    Um, yes it did! - and it's on going. They are unable to locate the corium in three reactors and spent pool fuel four is looking pretty precarious. If that collapses then it's bye bye Japan.

    (all this as well as contaminating land and sea)


  • Registered Users Posts: 8,410 ✭✭✭Markcheese


    Eirgrid have said spirit of Ireland (PHES powered by wind) is a non runner. I'm talking about similar scale powered by nuclears excess capacity(mainly at night) and not just in ireland, more likely in scotland and wales...... Also we've more or less used up conventional large scale hydro sites. But haven't really investigated pumped hydro storage sites fresh or salt water. we might use one in Ireland to balance another moneypoint scale coal plant (clean tech ??)

    Slava ukraini 🇺🇦



  • Moderators, Recreation & Hobbies Moderators, Science, Health & Environment Moderators, Technology & Internet Moderators Posts: 90,508 Mod ✭✭✭✭Capt'n Midnight


    the_syco wrote: »
    I wonder how much of Dublin will be powered by Sellafield...? Of the irony... :P


    You mean the earthquake and tsunami?
    We got hit by Tsunami's in 1755 (Lisbon Earthquake) and 1761

    http://www.politics.ie/forum/history/65636-1755-1761-tsunamis-ireland.html

    We are also at risk from Norway https://en.wikipedia.org/wiki/Storegga_Slide
    And La Palma in the Canaries https://en.wikipedia.org/wiki/Cumbre_Vieja#Future_threats


    No 6's but a couple of 5.8's next door in the past
    https://en.wikipedia.org/wiki/List_of_earthquakes_in_the_British_Isles

    Thing to remember about UK nuclear power is that it is being subsidised by a levy on other electricity so no real advantage in exporting it , even if they had some to spare. The interconnectors to Ireland mean the UK needs one less reactor, it's that simple.


  • Moderators, Recreation & Hobbies Moderators, Science, Health & Environment Moderators, Technology & Internet Moderators Posts: 90,508 Mod ✭✭✭✭Capt'n Midnight


    http://www.sciencespin.com/magazine/archive/2009/09/threatening-western-waves-/
    FACTFILE

    Historical records indicate that major storm waves or tsunamis have hit Ireland in 1640, 1755, 1839, 1852, 1854, 1941 and 1953.
    The evidence suggests that the events of 1755 and 1854 were tsunamis, and the 1852 event might have been a tsunami.
    Eyewitnesses reported of the 1839 event that "cod and conger were left squirming on the tops of sand dunes".
    During the 1852 storm/tsunami, 15 fishermen were swept off a cliff on Inishmore.
    The 1953 event killed 1,800 people in Holland, and 120 people died in the Irish Sea when a ferry sank.
    The Atlantic is prone to 'freak waves' which can reach up to 30 metres. These are more frequent than previously thought and are due to merging of waves during storms.


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  • Registered Users Posts: 8,410 ✭✭✭Markcheese


    the_syco wrote: »
    I wonder how much of Dublin will be powered by Sellafield...? Of the irony... :P


    You mean the earthquake and tsunami?
    We got hit by Tsunami's in 1755 (Lisbon Earthquake) and 1761

    http://www.politics.ie/forum/history/65636-1755-1761-tsunamis-ireland.html

    We are also at risk from Norway https://en.wikipedia.org/wiki/Storegga_Slide
    And La Palma in the Canaries https://en.wikipedia.org/wiki/Cumbre_Vieja#Future_threats


    No 6's but a couple of 5.8's next door in the past
    https://en.wikipedia.org/wiki/List_of_earthquakes_in_the_British_Isles

    Thing to remember about UK nuclear power is that it is being subsidised by a levy on other electricity so no real advantage in exporting it , even if they had some to spare. The interconnectors to Ireland mean the UK needs one less reactor, it's that simple.


    I agree with u about seismic activity,and I suppose if even a bad earthquake hit a rural, lightly populated not montainey area, then not much would happen..fatallaty wise.so not much would be recorded...

    On the uk nuclear power point. I suppose their reactors are providing their baseline power.so very little excess nuclear generated power, but in a situation where the uk has a net power shortage at peak times they'd happily export" off peak" power regardless of it's source, to provide a peak time boost.... Probably semantics anyway....

    Slava ukraini 🇺🇦



  • Registered Users Posts: 13,104 ✭✭✭✭djpbarry


    'Nothing really happened in Japan'?
    Once again, I meant relative to Chernobyl.


  • Moderators, Recreation & Hobbies Moderators, Science, Health & Environment Moderators, Technology & Internet Moderators Posts: 90,508 Mod ✭✭✭✭Capt'n Midnight


    Gbear wrote: »
    Spotted the thread.

    On the amount of Uranium left:
    from Scientific American article here: http://www.scientificamerican.com/article.cfm?id=how-long-will-global-uranium-deposits-last

    So at current rates that's 200+ years without taking into account technological advances and the use of thorium reactors. I'm not sure do those numbers include nuclear weapons stockpiles - they're another source that could be pushed for.
    Plenty of time to develop fusion.

    I think India are using thorium because they have large thorium deposits - probably the largest in the world.
    Nail, Head.

    You are saying Nuclear power is a temporary stop gap at best.



    at present rate of consumption nuclear power provides 13.5% or whatever of global electricity ,so to provide 100% of global electricity would be to burn it all up in 27 years.

    which is barely breakeven time to cover capital costs of the new reactors

    and in 27 years time you've a huge problem


    oh yeah that doesn't include increased demand from China , India , Brazil, Africa , or price increases, or changes in laws, costs of waste disposal not being spread over future generations of plant

    Weapons are usually counted , though the energy in reprocessing them may outweigh the benefits (not 100% sure on this , to do with making the plutonium so dilute that it's can't be weaponised )

    At present it's impossible to recover uranium from seawater, the petrochemicals / energy costs don't break even , you could use wind power but that's kinda missing the point


  • Registered Users Posts: 12,775 ✭✭✭✭Gbear


    Nail, Head.

    You are saying Nuclear power is a temporary stop gap at best.
    Until we achieve commercial fusion reactors (or some as of yet unknown technology) everything is a stop gap at best in my view.

    I think nuclear fusion is the closest thing ever discovered to magic. Getting massive quantities of cheap electricity using water and producing nothing harmful would blow everything else out of the water. I'm eagerly awaiting the end of the decade when ITER hopefully comes online.

    at present rate of consumption nuclear power provides 13.5% or whatever of global electricity ,so to provide 100% of global electricity would be to burn it all up in 27 years.
    That's taking some rather large leaps of logic.
    If we could instantaneously build the thousands of necessary reactors and their average efficiency was the same as that of all the current reactors then yes - it would burn up in 27 years.

    That fails to take into account the incremental improvements that happens with all technologies - 40 year old designs are not as good as new designs.

    It ignores the use of fast breeder reactors.

    It also ignores the possibility of the Thorium reactors - I think a huge reason the US didn't follow that path was due to them wanting nuclear proliferation. They can use the waste generated from traditional reactors.


    At present it's impossible to recover uranium from seawater, the petrochemicals / energy costs don't break even , you could use wind power but that's kinda missing the point

    I don't think it's impossible but it's certainly currently uneconomical.

    Much the same as the tar sands in Alberta over time, so too will seawater uranium extraction become more viable.


  • Registered Users Posts: 776 ✭✭✭Tomk1


    'Nothing really happened in Japan'?

    Um, yes it did! - and it's on going. They are unable to locate the corium in three reactors and spent pool fuel four is looking pretty precarious. If that collapses then it's bye bye Japan.

    (all this as well as contaminating land and sea)
    Actually it proves how safe N-reactors are, that aren't even up to the same safety specifications as the earthquake prone LA N-reactors.

    The Earthquake did no damage, The tsunami did no structual damage. What did do damage was the ineffective safety standards with an emergancy shutdown, like hitting the brakes on a 1000 m/hr train. I will be the 1st to admit that I might be going out on a limb, but if the reactors were not shut down nothing at all would have of happened and they would be working away aok today.

    What happened was, the Earthquake hit, out of safety the reactors were wound down, so no longer producing enough power to keep the cooling pumps running, the diesel generators to keep the pumps running got flooded after the huge wave breached the protection wall and then the backup batteries only had enough power to keep the pumps running for I think 8 hrs, after that the cooling of the reactors stopped. Like any power station if you turn off the cooling pumps it will blow the heat exchange side.

    With Fukushima, the reactors stayed intact after an earthquake, a tsunami stike, over heating and a fire. The real danger was spent fuel being stored on site.

    If you ask me it just shows what a battering a not the best built reactor can take. A real success story apart from the idiots running it. What annoys me is many thousands of people died due to the diasater and instead some people focus on a nuclear plant in which no one died as a case to turn people against Nuclear Energy, if only beds were built as safe as N-plants more people would be alive today. (statistically dieing from falling out of bed makes dieing due to nuclear energy a joke)-source Bang goes the Theory


  • Closed Accounts Posts: 7,230 ✭✭✭Solair


    Tomk1 wrote: »
    A Like any power station if you turn off the cooling pumps it will blow the heat exchange side.

    That is not really a very accurate statement.

    (I apologise for the length of this post, but I think some facts need to be set straight when it comes to what happened at Fukushima.)

    In other types of thermal power station i.e. heated with burning fuel (fossil fuel / biomass) once the flames are extinguished / burners switched off, there would be almost zero risk of anything other than damage to the boilers should the heat exchangers fail. There is no risk of environmental damage.

    The explosions at Fukushima Daiitchi were caused by STORED FUEL, not the reactors, they merely melted down and slowly burnt through the bottom of the reactor vessel. The contamination coming from cooling them by flushing sea-water through them and venting gasses up the stack.

    Even in other safer design of nuclear power station, e.g. the UK's Advanced Gas-cooled Reactors (AGR) and Magnox, there would be no problems in the event of a coolant loss as the core can cool passively.

    The major explosions at Fukushima were caused by a very fundamental design flaw.
    The particular type of fuel used in those reactors is clad in tubes of "zircaloy", an alloy that contains zirconium.

    The problem is that when heated beyond normal operating temperatures (and not by much) zircaloy oxydises in the presence of water or air! It's an exothermic reaction i.e. produces even more heat, so it can literally burn.

    To make it even worse, the when hot, it oxidizes in the presence of water, stripping oxygen from water molecules and producing explosive hydrogen

    So, basically if the fuel pools are allowed to warm up, they can catch fire and not only that but produce highly explosive hydrogen. This is what caused the serious damage to the plant and put the reactors into even worse situation than they had been in.

    Incidentally, the British AGR plants use stainless steel cladding which has none of these problems.

    The hydrogen explosions at Fukushima did immense damage to the control systems, the electrical systems, the pipework / ductwork and the structure of the building which made controlling the reactors even more difficult. They also possibly scattered fuel and radioactive debris all over the place.

    What is proves is that this is an absolutely lousy design of reactor, yet it is commonly used all over the US and elsewhere in Japan.

    I have a huge issue with the fact that it looks to me like these designs were kept top-secret back in the day so were never subjected to proper peer review or scrutiny. This was because at the time of construction, they were probably classified for cold-war reasons and because they did not want a situation where likes of North Korea (or Russia / China etc) could copy them and potentially use them to produce plutonium.

    So, because of all of that, some pretty awful designs seem to have been put into service!

    If that plant had been designed differently, even without the earthquake proofing, it would not have been a massive environmental disaster.

    Sadly, due to arrogant engineering and a total lack of transparency, the design was declared absolutely safe a bit like the way the Titanic was absolutely unsinkable.

    ALL existing reactors need to be examined for these kinds of fundamental design flaw.

    This is why, I don't like the whole concept of nuclear power, certainly with the existing designs of reactors anyway - if they go wrong, they go HORRIBLY wrong.

    Also, with other technologies, you have the possibility of having a learning curve i.e. you can have the odd disaster in the early days. People get killed / injured but the long-term consequences don't exist.

    Things improve bit by bit.

    This has been the case in industries like aviation where aircraft design errors have resulted in crashes, but the industry learns from those and irons out the bugs and planes have become incrementally safer and safer to the point that air travel is probably safer than walking down a street!

    With nuclear power, you have a situation where there are very few of these plants (hundreds), they are incredibly expensive, have long life spans and you have to build them from the point of view that mistakes cannot happen and every conceivable thing that could possibly go wrong has been thought of.

    Sadly, that's now how reality functions. We can't predict everything, even with the best computer modelling and best forecasting, things will go wrong.

    The consequences of an error are just too big, certainly with existing technology anyway, for me to see nuclear power as a reasonable option.

    Yet, according to some people posting on this forum, somehow that is an irrational or religious/dogmatic point of view?!
    Personally, I think I'm basing it on a lot of hard science and engineering.


  • Moderators, Recreation & Hobbies Moderators, Science, Health & Environment Moderators, Technology & Internet Moderators Posts: 90,508 Mod ✭✭✭✭Capt'n Midnight


    Gbear wrote: »
    Until we achieve commercial fusion reactors (or some as of yet unknown technology) everything is a stop gap at best in my view.
    Solar power in the Deserts / Oceans
    Cost of panels is €1/watt and dropping in a Moore's law way

    That's taking some rather large leaps of logic.
    If we could instantaneously build the thousands of necessary reactors and their average efficiency was the same as that of all the current reactors then yes - it would burn up in 27 years.

    That fails to take into account the incremental improvements that happens with all technologies - 40 year old designs are not as good as new designs.

    It ignores the use of fast breeder reactors.

    It also ignores the possibility of the Thorium reactors - I think a huge reason the US didn't follow that path was due to them wanting nuclear proliferation. They can use the waste generated from traditional reactors.
    You are ignoring that if there isn't a massive increase in the usage of nuclear it will become a niche power source.

    The improvements in nuclear aren't all that great. It's a Carnot engine and efficiency is related to the temperature of the steam. Meanwhile CCGT is hitting 59% in Aghada, which is a pipe dream with nuclear.

    Thorium / Fast breeder, come back when they are economic. Fast breeder is basically a means to produce plutonium for the military, French , US, USSR can't get them working economically so ...

    Thorium may be possible. And it's three times as abundant as uranium, still stop gap in the long run.


    Uranium extraction from seawater would have to become orders of magnitude more efficient, sponges and ion exchange and stuff. For the same sort of investment you could probably build tidal / wave powered stations extracting the same energy.


  • Registered Users Posts: 8,588 ✭✭✭SeanW


    Macha wrote: »
    Or you could flip it and say the major problem is having all these inflexible base-load hogging technologies as our major power source. Nuclear is very inflexible and can't ramp up or down to match demand.
    Some of the 'small nuclear' designs on the drawing board can ramp up and down. And no doubt with large amounts of unstable weather dependent renewables to "depend" on, this will be necessary. It would also make power cheaper (reduced transmission losses) if you had local "nuclear battery" type installations as opposed to large central fossil fuel fired power stations.
    As I mentioned in an earlier post, Europe's hydro potential has been largely exhausted but linking in existing hydro with RES is a different story altogether.
    RES? I've not heard of that before, care to explain?
    djpbarry wrote: »
    And yet you're convinced by the economic case for nuclear? That's a double-standard.
    Yes, because nuclear provides certain benefits, no CO2 from the plants, fuel trivially easy to store, large scale baseload and highly reliable. In some senses the opposite of fossil fuels (filthy, and with fuel (e.g. gas) that has to be imported day-by-day) and in every other sense the opposite of renewables (unreliable and uncontrollable).

    So if (and if is the key word) the government has to pay for the deep burial of waste or whatever, it's money well spent as far as I am concerned.
    Solair wrote: »
    What is proves is that this is an absolutely lousy design of reactor, yet it is commonly used all over the US and elsewhere in Japan.

    I have a huge issue with the fact that it looks to me like these designs were kept top-secret back in the day so were never subjected to proper peer review or scrutiny. This was because at the time of construction, they were probably classified for cold-war reasons and because they did not want a situation where likes of North Korea (or Russia / China etc) could copy them and potentially use them to produce plutonium.

    So, because of all of that, some pretty awful designs seem to have been put into service!

    If that plant had been designed differently, even without the earthquake proofing, it would not have been a massive environmental disaster.

    Sadly, due to arrogant engineering and a total lack of transparency, the design was declared absolutely safe a bit like the way the Titanic was absolutely unsinkable.

    ALL existing reactors need to be examined for these kinds of fundamental design flaw.
    I agree, almost totally! Ever since I became a pro-nuke, I've been railing against bad reactor design, the biggest example being the RBMK that lead (along with Communist (mal)practice) to the Chernobyl disaster.
    Also, with other technologies, you have the possibility of having a learning curve i.e. you can have the odd disaster in the early days. People get killed / injured but the long-term consequences don't exist.

    Things improve bit by bit.
    And yes, despite being a young technology, nuclear energy has already improved massively in the ~60 odd years its been in large use - there were foul ups with bad early technology (pollution of beaches in the U.K. the Windscale fire) but that tends to happen less now.
    This has been the case in industries like aviation where aircraft design errors have resulted in crashes, but the industry learns from those and irons out the bugs and planes have become incrementally safer and safer to the point that air travel is probably safer than walking down a street!
    Yet we still have plane crashes.
    The consequences of an error are just too big, certainly with existing technology anyway, for me to see nuclear power as a reasonable option.

    Yet, according to some people posting on this forum, somehow that is an irrational or religious/dogmatic point of view?!
    Personally, I think I'm basing it on a lot of hard science and engineering.
    How so? Fossil fuel power does more harm in one year than nuclear power has done in its entire time in use on Earth - and I include the Chernobyl disaster in that.

    There are a large array of facts (Carbon Dioxide emissions, human deaths per TW/h) to show that a nuclear programme can be run safely, far safer for the environment and the general public's health than fossil fuels. We could be assured of our energy security by (easily) building a stockpile of nuclear fuel.

    You even admitted that Fukushima was caused by specific, known plant flaws and practices inherited from the Cold War (which ended 20 years ago).


  • Moderators, Recreation & Hobbies Moderators, Science, Health & Environment Moderators, Technology & Internet Moderators Posts: 90,508 Mod ✭✭✭✭Capt'n Midnight


    SeanW wrote: »
    Some of the 'small nuclear' designs on the drawing board can ramp up and down.
    6 hours ? 18 hours ?
    what about the Xenon poisoning ?

    And lets not forget that snafu with the pebbles getting stuck in the German test.

    There is a reason they are still on the drawing board.

    Yes, because nuclear provides certain benefits, no CO2 from the plants, fuel trivially easy to store, large scale baseload and highly reliable. In some senses the opposite of fossil fuels (filthy, and with fuel (e.g. gas) that has to be imported day-by-day) and in every other sense the opposite of renewables (unreliable and uncontrollable).
    you've never heard of gas storage ? :eek:
    So if (and if is the key word) the government has to pay for the deep burial of waste or whatever, it's money well spent as far as I am concerned.
    It's €3 Bn
    If we get half our power from nuclear that's €1 per installed Watt.
    That's the sort of price the UK are paying for offshore wind.

    I agree, almost totally! Ever since I became a pro-nuke, I've been railing against bad reactor design, the biggest example being the RBMK that lead (along with Communist (mal)practice) to the Chernobyl disaster.
    What about the Japanese reactors ?
    Or the Californian one with the earthquake shield build backwards ?
    Or the Indian one with the radioactive control room ?
    Or the UK ones ?
    Or the German pebble bed one ?
    Or the cost overruns and cheapo labour on the Finnish one ?
    Can't remember if it was French but there was a reactor where the construction lads used to take a leak in the rebar sockets 'cos it was a long way down. Can't be good for corrosion in years to come.

    Point is most countries have had major issues with reactors, and multiple safeguards only go so far because we are building better idiots all the time. Sellafield Fire ?


    And yes, despite being a young technology, nuclear energy has already improved massively in the ~60 odd years its been in large use - there were foul ups with bad early technology (pollution of beaches in the U.K. the Windscale fire) but that tends to happen less now.
    How has it improved relative to what could have been done in the 1950's if they had to follow today's emission standards. (apart of course from having hotter steam because of better steel)


    How so? Fossil fuel power does more harm in one year than nuclear power has done in its entire time in use on Earth - and I include the Chernobyl disaster in that.
    Citation needed for that
    also citation needed to show that nuclear power has produced more than 1/60th of the amount of power than the amount of fossil fuel used to day.


    Few if any of the failings of nuclear plants were unknown in the 1950's.


    Do you have any stats on early deaths of mine workers in Africa ?


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  • Moderators, Recreation & Hobbies Moderators, Science, Health & Environment Moderators, Technology & Internet Moderators Posts: 90,508 Mod ✭✭✭✭Capt'n Midnight


    http://www.psr.org/news-events/news-archive/psr-cost-of-wind-power-far-lower-than-coal.html
    Dr. Thomasson in her testimony compared the costs to the public’s health from coal combustion against the generation costs of offshore wind. Health costs from coal contaminants far outweigh the additional costs of wind.
    ...
    Even looking at only those three pollutants, analysis shows that the generation of 310 megawatts from offshore wind – the amount being proposed for the Maryland wind farm – would save $100 million in public health, thanks to the avoidance of premature deaths attributed to coal combustion.


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