Gen 3 Nuclear Power Plants' Minimal Fuel Use
- Oct 26, 2011 9:19 pm GMT
- 792 views
In one of the entries on my series of posts on the Integral Fast Reactor, I pointed out that a next-generation nuclear-power-plus-full-fuel-recycling plant would require only 1 tonne of natural uranium fuel (or thorium, or nuclear waste, or depleted uranium) per year, for a 1,000 MWe plant. However, I recently got asked this related question:
Do you know of any sources where I can find what the fuel requirements would be for a typical 1 GW Gen 3 plant running for a year?
This is an interesting question. Two obviously modern plants to consider are the Westinghouse AP1000 (four are currently under construction in China) and the AREVA EPR (two are being built in Europe).
The AP1000 uses 4.25 % enriched fuel and achieves a burnup of 60 GWd/t (details here). The EPR uses 5% enriched fuel to get 62 GWd/t (details here). The following Excel table illustrates my calculations (blue = inputs, green = calculations, bold = results) — click on the table to download the .xlsx file and play around with it yourself.
This estimates a natural uranium metal use of 108 to 117 tonnes U per GWe per year, using an enriched fuel loading of 21 to 25 t for the two designs (1,115 and 1,650 MWe respectively, running at about 92% capacity factor). The EPR appears to be slightly more efficient than the AP1000 when levelised on a 1 GWe basis.
My calculations, based on the performance documentation, are similar to the generalised calculations provided by the WNA, as given below:
(There are small discrepancies — if anyone can work out the sources of these, please let me know in the comments)
These Gen III+ plants are quite efficient in their fuel use (see the briefing paper The Nuclear Fuel Cycle for a detailed description of the different inputs — from which the above table was extracted). Depending of the grade of ore, this metal fuel will typically require the processing of 20,000 to 400,000 tonnes of mined ore. As explained in this excellent comment by Luke Weston (reproduced at the foot of this post), in polymetallic mines, this ore may already be extracted for other purposes. For in situ leach mining, the extraction process is different.
The above are idealized calculations for the newest, fuel efficient designs. If you want a rough figure for older reactors (which actually aren’t that much worse), the estimate of fuel use is about 24 t of enriched U per year, or up to 200 tonnes of natural uranium per GWe: see http://www.world-nuclear.org/education/whyu.htm
Finally, an interesting video to look out for. Now uploaded in full on YouTube, this excellent BBC documentary (57 min) was first broadcast on 14 Sept 2011. It is hosted by Professor Jim Al-Khalili, and entitled “Is Nuclear Power Safe“.
Here is the blurb:
Six months after the explosions at the Fukushima nuclear plant and the release of radiation there, Professor Jim Al-Khalili sets out to discover whether nuclear power is safe.
He begins in Japan, where he meets some of the tens of thousands of people who have been evacuated from the exclusion zone. He travels to an abandoned village just outside the zone to witness a nuclear clean-up operation.
Jim draws on the latest scientific findings from Japan and from the previous explosion at Chernobyl to understand how dangerous the release of radiation is likely to be and what that means for our trust in nuclear power.
Appendix: Luke Weston on Gavin Mudd
In response to Gavin Mudd’s ridiculous article about the Olympic Dam expansion over on The Conversation, I wrote a lengthy comment in response. It’s posted over there but I will also copy it here for interested readers.
Contrary to the usual tendentious nonsense from anti-nuclear activists, Olympic Dam is not really a uranium mine. Olympic Dam is a copper mine. Following the expansion, the total copper production at Olympic Dam will be 730,000 tonnes per year, up from about 220,000 tonnes per year at the present. (Copper smelting is, incidentally, what requires most of the energy input to the Olympic Dam site, nothing to do with uranium.) After the ore is mined and milled, the copper minerals are separated and processed and we’re left with powdered mineral waste – the so-called tailings which seem to be a cause for great concern amongst environmentalists.
At Olympic Dam, however, those tailings contain a small amount of gold and uranium, and further processing of the ore (which you’ve already mined and milled anyway) to separate the gold and uranium into saleable products is economically attractive. (If those same relatively low concentrations of U and Au were present in an orebody that was not already being mined for the copper anyway, mining such a deposit would not be economically attractive.)
The gold and uranium are essentially “free” byproducts recovered from what would otherwise be tailings from the copper mine, with no additional mining – no additional hole in the ground – required to extract those resources. In this sense, it would appear that polymetallic Cu/Au/U extraction operations at Olympic Dam are actually a very environmentally friendly way to mine those metals, as opposed to the alternative of having additional, separate mines at other sites mining gold and uranium deposits. Getting the most value that you can practically get out of one single hole in the ground is an environmentally efficient, conscious approach to mining.
As Mudd points out, the Olympic Dam orebody contains rare earths, which are essential for wind turbines, LEDs, electric vehicles, fuel cells and the like, and for which demand is growing rapidly. I’m sure BHP Billiton is well aware of the chemistry of the Olympic Dam orebody, and as the price of rare earths continues to rise over the coming years, I’m sure they will pursue rare-earth extraction at the point when it becomes economically viable. As with gold and uranium, extracting these different elements from the polymetallic orebody is an environmentally friendly alternative to having multiple additional mines. (Incidentally, all other rare-earth mining prospects in Australia also seem to attract criticism from the predictable band of anti-nuclear “environmentalists”, who complain that horrible, radioactive, scary uranium and thorium will also be extracted from these polymetallic ores where it is present along with the lanthanide metals.)
What exactly does Mudd propose we should do with the uranium at Olympic Dam, if the status quo is not the way to go? If we are to mine the copper and gold (and perhaps rare earths too), then of course the ore that is mined contains the uranium as well. Should we simply cease the extraction of uranium from that ore? But that would simply leave all that uranium in the tailings – significantly increasing the amount of radioactivity present in that tailings waste, whilst of course it would not at all decrease the volume of that tailings waste or change its characteristics in any other way. Given the concern expressed by Mudd and other anti-nuclear activists about those scary radioactive tailings, leaving the uranium in the tailings does not seem to make sense at all.
Mudd calls the mine tailings “billions of tonnes of radioactive waste”, calling to mind nonsense fictional mental images of billions of rusty 44-gallon drums full of luminous green goo, but in fact those tailings really are just natural rock that comes out of the ground. The tailings contain natural uranium and the natural daughter-product radionuclides in the uranium series, all naturally created and naturally present in the ground. Mining the ore and extracting the uranium does not create, or add, or change the radioactivity of this natural material in any way – except for removing the uranium from it.
Removing the uranium (well, essentially all of it, not 100% of it) from the tailings removes most of the uranium daughter-product radionuclides (Ra, Rn, Po etc.) that will form in the tailings over the long term, into the future, and will therefore remove most of the radiation dose that workers or the public may be exposed to from exposure to said tailings (a long time in the future). Leaving the uranium in the tailings, as well as the uranium daughter radionuclides that the uranium will become over long timescales, will substantially increase the radioactivity and potential radiation dose from those tailings.
If you live in a part of the world where uranium (and uranium daughters) are naturally geologically abundant, then you’re exposed to natural background ionising radiation dose from that natural geology – from uranium, radium and the other uranium daughters in the soil, in dust, from gamma radiation directly from the ground, from radon in the air, and from uranium and uranium daughters in water. All these background dose pathways are completely natural – they’re a fact of life. If you’re afraid of that, move to a location where the natural geology contains minimal uranium or thorium.
Does the mining by humans of these natural rocks that contain uranium and its daughter products actually cause any real change to the background ionising radiation dose rate that people receive from that natural radioactivity, compared to the radiation doses received anyway when that radioactivity just sits in the ground naturally (and is subject to natural erosion, natural geological and hydrogeological transport) and does not get mined? Good question… perhaps Dr. Mudd could point us to some research or evidence on this subject.
It is a well-worn and predictable rhetoric sound-bite from the likes of Mudd, Ludlam, Diesendorf and Lowe that Australia’s uranium exports, in terms of revenue dollars, are less than Australia’s exports of cheese or lamb. But these people should know better than to simply think about everything in terms of the economist’s bottom line when it comes to science-based ecology and environmental best practice.
In the 2010 calendar year, Australia exported 301 million tonnes of coal, which corresponds to about 7.2 * 10^18 J of thermal energy content. The 7555 tonnes of natural uranium oxide exported in 2009-2010 contains a thermal energy content (ignoring the thermodynamic losses in a heat-engine power station, and assuming inefficient, once-through use of low-enriched uranium in LWRs) of about 3.4 * 10^18 J.
Australia’s three modest uranium mines provide a total energy output which is about 50% of all of Australia’s coal exports (a bit more than 50% of Australia’s total coal output including domestically-consumed coal). And yet this clean energy resource is supplied from three mines which have a total environmental footprint on the landscape which is far, far smaller than 50% of the environmental footprint of Australia’s numerous coal-mining holes in the ground. 15,000 tonnes of uranium oxide would give you the same energy output (in LWRs) as all that coal, and 15,000 tonnes of mineral production is a hell of a lot less environmentally intensive than 301 million tonnes.
Clearly Australia’s uranium exports are not essential for Australia’s economy. But such an enormous resource of clean energy, with such a high energy density, which is abundant in the earth and is available at such a low cost is obviously incredibly valuable and important for the global environment.
Following the expansion of mining operations at Olympic Dam, the mine will produce about 19,000 tonnes of uranium oxide per year, which will generate (in relatively inefficient once-through use in LWRs) about 800 TWh of electricity. Over the coming years, Australia’s clean energy exports (in the form of uranium) are likely to provide enough clean coal-replacement capacity to catch up with, and offset, the greenhouse gas emissions from all of Australia’s coal exports.
When natural uranium is used very efficiently, in the Integral Fast Reactor for example, one tonne of natural uranium oxide (U3O8) will yield about 8 * 10^16 J of thermal energy in the reactor. Therefore, if the 19,000 tonnes of uranium oxide from the Olympic Dam expansion was to be used in this way, the amount of energy produced would be about 1.5 * 10^21 J (thermal) – an amount of clean energy nearly 10 times greater than the energy content (about 1.7 * 10^20 J) of all the coal production on Earth. That’s basically all the energy for all the world. And for all the people that don’t yet have access to electricity. From just one mine!
Given that Australian-Obligated Nuclear Material is carefully safeguarded and watched and is not allowed to be diverted into nuclear weapons (and in fact most of this material, such as depleted uranium, highly radioactive used fuel which contains some reactor-grade plutonium in it, and reprocessed reactor-grade plutonium, is not physically useful as the fuel for nuclear weapons), would Mudd care to explain to us exactly how Australia’s uranium exports are “potentially increasing nuclear weapons risks”?
Depleted uranium, used LWR fuel and recycled reactor-grade plutonium are not a “burden” – they are enormous resources of fuels for clean energy which can be used throughout the world to provide energy, replacing the need to mine a hell of a lot of coal – and indeed, replacing the need to mine lots of new uranium which might otherwise be used.
Mudd lists “massive energy consumption” amongst the mine’s other supposedly negative effects. In fact, Olympic Dam has an enormous “energy gain” – the mine’s clean energy production (in the form of uranium) is far, far in excess of the mine’s total energy inputs. The highly efficient use of uranium, for example in the Integral Fast Reactor, as opposed to enrichment and inefficient once-through use of low-enriched uranium in light-water reactors, will increase that “energy gain” enormously.
Australia is, and will certainly continue to be, a major exporter of uranium, for civilian nuclear energy use under strict safeguards, to the world. This uranium has a very valuable role in providing clean, safe, abundant energy to replace coal and fossil fuel use throughout the world – today and into the future.