Nuclear Power - debate / poll

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Originally Posted by JDNSW

The difference of course is that a nuclear power station has a daily consumption of uranium measured in kilograms, where the coal fired power station uses thousands of tonnes of coal a day. Coal fired power stations already clean up almost all their emissions except carbon dioxide and water. And the carbon dioxide is the problem. One of the things that annoys me is that every time there is a mention of air pollution from power stations on TV is there is the obligatory shot of steam rising from cooling towers - which, of course is not pollution. And carbon dioxide cannot be seen.

The mining damage caused by all the world's uranium mines since mining started is less than the damage caused by one open cut coal mine in a few days. A typical uranium mine produces a few tonnes of ore per day, a typical coal mine produces hundreds of tonnes of coal an hour plus thousands of tonnes of overburden shifted.

The scale of the materials (coal/uranium) is vastly different for the same amount of power, and the same applies to the energy used to transport and process it, even if the uranium needs more processing.

John

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John, the plant that I worked on at Mary Kathleen when it was recommissioned was capable of over 1000 tonnes of ore/day, I would imagine that it was probably actually processing less than that, it was a very Power intensive operation, Diesel for the explosives (Ammonia Sulphate and diesel), Diesel for the Loaders and 50 tonne Dump trucks and for the Cyclone which heated the yellow cake into Uranium Oxide, electricity for the crushing mills and sorters, conveyors and pumps.
if you look at Rum Jungle and Mary K you will see the devastation caused by the tailings dams, even after the Clean-ups, Regards Frank.

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Originally Posted by JDNSW

1. I am at a loss to understand how nuclear power produces far more heat or uses far more water than coal. Both provide a source of heat used to generate steam which is used in a heat engine to provide rotary power that is used to drive an alternator. Both are essentially identical apart from the heat source, and both require either cooling towers or large volumes of cool water to maintain the heat difference that the Carnot cycle requires. The only difference is that the coal burning station operates at a higher temperature, resulting in slightly greater efficiency, and hence slightly less heat dumped into the environment - but of course, 90% of the power generated ends up as heat dumped in the environment anyway, so the difference in amount of heat to the environment overall is negligible.
2. The problem with CO2 is not the life of it (and this is not well understood!) but the sheer volume of it! At least nuclear waste is very small in volume.
3. My point about mining was in response to Tank's comments about mining.

There are more people killed every year in China alone than all the deaths that can be attributed to Chernobyl. While the Russian figures of less than 100 are almost certainly understated, some of the other figures are vastly overstated, being calculated as an estimate of the number of deaths that will eventually result from the known spread of radiation. But these estimates assume there is no safe threshold for exposure, ignoring the fact that we are all exposed to radiation from natural sources and have evolved to cope with it. If you are going to include these sort of figures from Chernobyl you have to include the equivalent figures from emission of K40 from coal fired power stations, and again, while these emissions are relatively small as a proportion of emissions, the overwhelming number of coal fired power stations and the volume of emissions from each more than makes up.

4. I think that carbon sequestration of coal fired power station emissions will eventually become feasible, and this is one of the main reasons why I am unsure about nuclear. But if you think it is going to be significantly cheaper than nuclear, you are kidding yourself. This is an area where I have a pretty good idea what is involved, and I have a reasonable idea of the sort of costs that will result.

To continue to produce CO2 emissions at the present rate will leave our children with a legacy of flooded cities and changed environment. Unfortunately, as I have commented earlier in this thread, what Australia does is pretty much irrelevant - the only countries that really matter are the US, China and India, possibly Europe.

John

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John, we are at the moment living and surviving with all the CO2 released to the atmosphere, that will change in the future and the effects will be devastating if nothing is done to reduce or stop CO2 production, one of the largest sources of CO2 is Methane from Cattle Farts and Belches, Methane in the atmosphere eventually becomes CO2.
But back to the waste issue, whether Co2 or Nuclear waste, as I said above humankind is surviving and are taking steps to remedy the problem, BUT if you took all of the waste from Nuclear Power generation from, say, France and introduced it into the earth's atmosphere, that would be the END of all LIFE on this planet, not something that can be adapted to or remedied, I cant see why the proposed money to be spent on Nuclear power cant be used to improve CO2 levels through new technology, like clean coal, Wind, Wave, Solar power, It makes sense to me, Regards Frank.

One thing people have been forgetting is the ongoing cost of storage and shipping of the used uranium.
If uranium is stored,it looks like it will be in the NT some where deep under groung in a concrete vault.
How much will it cost to build this vault?
How long will it last ? no one is saying.
But lets take a look quick at it. Lets say a structure like that would cost say about 10mil. (on the conservative side) and Serurity for the site 24/7 with about 12 people at say $700 p/w would cost $436 800 p/a.
Now lets look at transporting the spent fuel say from Brisbane.
For a return trip its about (shortest distance) 5000km. Shipping out by truck would cost about $6000.00 in fuel alone just for one trip if the truck makes 1 trip a week thats $312 000p/a. On fuel alone not taking into account the ongoing maintainance of this one vehicle it's starting to add up. Now i know your gonna say thats just bull, but if your going to agree to nuclear power you really have to look at all the costs not just the running cost of the plant, and don;t forgat these costs have to keep going for over 10000 years which is the half life of nuclear fuel.

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Originally Posted by Tank

John, the plant that I worked on at Mary Kathleen when it was recommissioned was capable of over 1000 tonnes of ore/day, I would imagine that it was probably actually processing less than that, it was a very Power intensive operation, Diesel for the explosives (Ammonia Sulphate and diesel), Diesel for the Loaders and 50 tonne Dump trucks and for the Cyclone which heated the yellow cake into Uranium Oxide, electricity for the crushing mills and sorters, conveyors and pumps.
if you look at Rum Jungle and Mary K you will see the devastation caused by the tailings dams, even after the Clean-ups, Regards Frank.

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Yes, MKU is a large uranium mine, - but the fact remains that a typical coal mine produces of the order of thousand tonnes an hour - and ten to twenty times that of overburden. And you have to allow for the fuel (or power) used by the draglines, conveyors, trucks, trains, explosives etc for coal mining, and because the tonnages are 100 times greater than for nuclear, so are the transport costs. The devastation caused by tailings dams and so on exists regardless of what is being mined - and there is far more coal mined than uranium. And you get the same sort of thing from base metal mining, and there is far more of that than there is uranium mining.

But the devastation left by mining is negligible compared to that caused by cities!

John

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Originally Posted by shorty943

check this Aussie site, from Melbourne. http://www.uic.com.au/nip08.htm It will make a mockery of all the emotive rubbish on costs for Nuclear Power Generation.

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I think I have the answer to part of the mystery about cost of coal versus nuclear or at least the discrepancy between what this site says and what so many other sources say.
I just noticed what was missing from the figures on this site.
Even though it is an Australian site, it doesn't include the cost of coal fired power in Australia. It seems to have concentrated on countries where coal is obviously more expensive than in Aus.

In fact there is a clue in the intro where it says:

• Nuclear power is cost competitive with other forms of electricity generation, except where there is direct access to low-cost fossil fuels.

The relative costs of generating electricity from coal, gas and nuclear plants vary considerably depending on location. Coal is, and will probably remain, economically attractive in countries such as China, the USA and Australia with abundant and accessible domestic coal resources....

Bit easier to get the results you want if you select the right countries to include

Read a great sci-fi short story once where people in the future invented a time machine. They sent one person back to the 20th century who pretty quickly passed out, same with the second, and the third, until they worked out what was going on.

Our breathing response is triggered by build up of CO2 in the blood, not lack of oxygen. They had adapted to much higher levels of CO2 so when they arrived in the relatively clean air of the 20th century, they simply forgot to breathe.

Very clever I thought. (And this was written at least 20 yrs ago!)

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Originally Posted by vnx205

..........Bit easier to get the results you want if you select the right countries to include..........

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Unfortunately this is the problem with the nuclear debate (and a lot of other public discussions) - almost everyone picks the answer they want and then looks for the evidence/assumptions/published papers etc that gives the answer that they want -( apart from the ones who just invent their figures. )

In the Australian context this is made easier by the fact that there tend to be a lot more data available for countries with a larger population - but whether it applies here is often very doubtful, and even if it does, you rarely know that it does.

John

I have a purely innocent question re nuke power stations: I hear that Japan and France (and others) use nuke as the principal source of electricity generation, without apparent drama and have been doing so for many years...

I also read that many say that nuke is bad.

I understand the issue of spent nuke fuel and where to store it.

My question is: Given that several other countries have been using nuke fuel for maybe 30 years or more, where are they storing the spent nuke waste, how much stored waste exists and what is its actual and genuinely real danger?

I have no bias (short of an objection to paying lots more $$$ for my electricity) and have already stated my 'sitting on the fence' position.

I do not know this, what I've asked, and having read a bit about this form of power generation, the info is scant - apparently for 'security reasons'...

GQ

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Originally Posted by Quiggers

I have a purely innocent question re nuke power stations: I hear that Japan and France (and others) use nuke as the principal source of electricity generation, without apparent drama and have been doing so for many years...

I also read that many say that nuke is bad.

I understand the issue of spent nuke fuel and where to store it.

My question is: Given that several other countries have been using nuke fuel for maybe 30 years or more, where are they storing the spent nuke waste, how much stored waste exists and what is its actual and genuinely real danger?

I have no bias (short of an objection to paying lots more $$$ for my electricity) and have already stated my 'sitting on the fence' position.

I do not know this, what I've asked, and having read a bit about this form of power generation, the info is scant - apparently for 'security reasons'...

GQ

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Partly, as you say, for security, it will be hard to find out any great detail.
When spent fuel rods are removed from a reactor, they are highly radioactive and producing a good deal of heat as a result. They are stored on site, cooled by water for several years until the radioactivity decreases to the extent that the material can be concentrated without getting too hot. It is then packed, usually into shielded drums, and transported in containers to a reprocessing facility where the chemical makeup is sorted out chemically to remove useful components and convert the material into chemically stable forms which are then encapsulated in concrete for long term storage.
As far as I know there is no waste in permanent long term storage, and this is all in "temporary" storage.

How dangerous is it? The rods directly from the reactor have to be handled by remote control and direct contact or even getting within a metre or so of them will cause local radiation burns and be rapidly fatal. The "cooled" rods are slightly less dangerous but when packed for transport are safe in the short term anywhere outside the container, although you probably wouldn't want to camp for long term on top of the container. The processed and packed processed material is relatively low in external radiation and almost impossible to get the radioactive material out of the packaging.

The radioactive waste itself contains a very wide range of elements with widely varying degrees of danger. The ones that are dangerous are the ones that are easily taken in to the body and retained by the body. A good example is Iodine. Because of this it is necessary to make sure it is retained in the rods until processed and then chemically bound into a stable insoluble form. On a slightly different scale are isotopes that are acutely poisonous such as plutonium (which is carefully removed from the processed material because it is valuable).

It is very difficult to steal radioactive material for terrorist purposes - even if the thief knows exactly what they are doing, they are likely to incur fatal radiation poisoning while taking it. - and they will be very easy to trace (as was demonstrated in the recent case of poisoning of a Russian emigre).

There have been a number of cases of accidental injury and death from radioactive waste. In all the cases I know of they have been a result of the improper disposal or theft of medical or industrial equipment containing radioactive materials. In this regard, the biggest danger is probably smoke detectors.

John

Thank you John.

I saw Dr Karl on telly a while back saying the way to store waste was dig a big hole about a kilometre deep and at this depth have large chambers, and as each chamber was stocked with waste (these are 200 litre type drums?) encase the chamber with concrete.

Sounded simple but I wonder if the packages would eventually leach radiation....

Why not pack it on rockets and send it to the sun?

GQ