Talk:DEMO
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DEMO is the name of a proposed fusion reactor, so i chose to create a page here. This unfortunalty ment removing a redirevt page to Demo (comics). I hope no one is bovvered. mastodon 23:50, 1 February 2006 (UTC)
[edit] Notability
Is the project famous enough to deserve its own article? There are no references of any kind. --Elonka 16:19, 29 October 2006 (UTC)
- Hopefully I have corrected this problem and the notability tag can be removed. I will not remove it myself, however. --Ben Best 07:46, 11 November 2006 (UTC)
[edit] 400, 480 or 500 seconds?
The ITER article says that ITER is designed to run for 500 seconds (and in another place: 'for 8 minutes' - or 480 seconds). This article says 400 seconds. I'm going to assume the ITER article is correct and change it to 500 here. If anyone has knowledge that 400 is indeed the right number then they need to fix the ITER article as well as this one. SteveBaker 18:45, 22 November 2006 (UTC)
From iter.org: ITER will produce about 500 MW of fusion power in nominal operation, for pulses of 400 seconds and longer.--83.38.193.187 17:03, 28 September 2007 (UTC)
[edit] Radioactive waste
Article currently reads As a prototype commercial fusion reactor DEMO could make fusion energy (which does not produce the global warming or pollution of fossil fuel, nor the long-lived radioactive waste of fission energy) available within 20 years. The ITER article quotes a Greenpeace activist as saying Nuclear fusion has all the problems of nuclear power, including producing nuclear waste and the risks of a nuclear accident.
They can't both be right, and I actually think Greenpeace has it right here on the waste issue. According to the current article (and AFAIK), DEMO will use the D + T reaction. But the current article also states It is hoped that careful material choice will mean that the wastes produced in this way will have much shorter half lives than the waste from fission reactors, with wastes remaining harmful for less than one century. These are weasel words. Yes, many would like to think this will happen, because unless it does happen, fusion won't be able to compete with fission on environmental grounds, as many would like to think it will. But there is no evidence as yet to support this hope, and there are many reasons to doubt it.
But whoever is right, the claim that DEMO could make fusion energy (which does not produce... the long-lived radioactive waste of fission energy) available within 20 years is clearly POV. And even the most optimistic material from the ITER participants themselves doesn't support it. Rather, testing of these materials won't even start until IFMIF comes online about 2017, having taken ten years to build. If DEMO then takes another ten years to build, the testing program for its lining materials would need to be completed in zero years in order to meet the twenty year deadline.
This is obviously not going to happen, but it's only half the story. It's also interesting to note that IFMIF will only subject the materials to real-time testing. The possibility of accelerating the testing program, as was done for fission reactor cladding materials in particular, by using an even higher neutron flux does not exist, because higher fluxes are just not available. They are pulling out all stops to even achieve that predicted neutron flux of DEMO, without trying to exceed it. So, even if you only want to keep the lining material for two years between changes, which is probably too short an interval for any commercial reactor, each test of each new formulation will take two years... and that's also assuming 100% availability of IFMIF for those two years. Andrewa 02:00, 24 June 2007 (UTC)
- The material testing is already in progress, albeit with less suitable neutron sources. The new facilities are being built to accelerate the process, and provide more reliable data to ensure it will indeed be successful. Also, even if normal steel was to be used, the longevity of the waste would still be orders of magnitudes shorter than existing nuclear reactors. The potential for a serious accident which would end up causing harm to humans is almost nil, as outlined in the article on fusion power. Also, when it comes to materials, my understanding is that the plan is to use Vanadium based alloys for the structural materials, and possibly carbon for the plasma-facing compounds. Vanadium produces no long-lived isotopes upon neutron irradiation, and while carbon would result in some radioactive waste, it would be dramatically less troublesome than the fission products, let alone the actinides. In light of this, I would argue that the greenpeace statement is extremely misleading at best, outright false at worst. It is clear that even if the materials project is not successful, the waste generated would still be orders of magnitude lower in quantity and longevity than that from nuclear reactors, and the risk of accidents causing harm to the public is similarly much less. 85.230.195.192 03:26, 23 October 2007 (UTC)
