{"id":4676,"date":"2015-10-27T18:51:45","date_gmt":"2015-10-27T23:51:45","guid":{"rendered":"http:\/\/helian.net\/blog\/?p=4676"},"modified":"2015-10-27T18:51:45","modified_gmt":"2015-10-27T23:51:45","slug":"another-fusion-white-elephant-sighted-in-germany","status":"publish","type":"post","link":"https:\/\/helian.net\/blog\/2015\/10\/27\/nuclear-energy\/another-fusion-white-elephant-sighted-in-germany\/","title":{"rendered":"Another Fusion White Elephant Sighted in Germany"},"content":{"rendered":"

According to an article that just appeared in Science magazine<\/a>, scientists in Germany have completed building a stellarator by the name of Wendelstein 7-X (W7-X), and are seeking regulatory permission to turn the facility on in November.\u00a0 If you can’t get past the Science<\/em> paywall, here’s an article <\/a>in the popular media with\u00a0some links.\u00a0 Like the much bigger ITER facility<\/a> now under construction at Cadarache in France, W7-X is a magnetic fusion device.\u00a0 In other words, its goal is to confine a plasma of heavy hydrogen isotopes at temperatures much hotter than the center of the sun with powerful magnetic fields in order to get them to fuse, releasing energy in the process.\u00a0 There are significant differences between stellarators and the tokamak design used for ITER, but in both approaches the idea is to hold the plasma in place long enough to get significantly more fusion energy out than was necessary to confine and heat the plasma.\u00a0 Both approaches are probably scientifically feasible.\u00a0 Both are also white elephants, and a waste of scarce research dollars.<\/p>\n

The problem is that both designs have an Achilles heel.\u00a0 Its name is tritium.\u00a0 Tritium is a heavy isotope of hydrogen with a nucleus containing a proton and two neutrons instead of the usual lone proton.\u00a0 Fusion reactions between tritium and deuterium, another heavy isotope of hydrogen with a single neutron in addition to the usual proton, begin to occur fast enough to be attractive as an energy source at plasma temperatures and densities much less than would be necessary for any alternative reaction.\u00a0 The deuterium-tritium, or DT, reaction will remain the only feasible one for both stellarator and tokamak fusion reactors for the foreseeable future.\u00a0 Unfortunately, tritium occurs in nature in only tiny trace amounts.<\/p>\n

The question is, then, where do you get the tritium fuel to keep the fusion reactions going?\u00a0 Well, in addition to a helium nucleus, the DT fusion reaction produces a fast neutron.\u00a0 These can react with lithium to produce tritium.\u00a0 If a lithium-containing blanket could be built surrounding the reaction chamber in such a way as to avoid interfering with the magnetic fields, and yet thick enough and close enough to capture enough of the neutrons, then it should be possible to generate enough tritium to replace that burned up in the fusion process.\u00a0 It sounds complicated but, again, it appears to be at least scientifically feasible.\u00a0 However, it is by no means as certain that it is economically feasible.<\/p>\n

Consider what we\u2019re dealing with here.\u00a0 Tritium is an extremely slippery material that can pass right through walls of some types of metal.\u00a0 It is also highly radioactive, with a half-life of about 12.3 years.\u00a0 It will be necessary to find some way to efficiently extract it from the lithium blanket, allowing none of it to leak into the surrounding environment.\u00a0 If any of it gets away, it will be easily detectable.\u00a0 The neighbors are sure to complain and, probably, lawyer up.\u00a0 Again, all this might be doable.\u00a0 The problem is that it will never be doable at a low enough cost to make fusion reactor designs based on these approaches even remotely economically competitive with the non-fossil alternative sources of energy that will be available for, at the very least, the next several centuries.<\/p>\n

What\u2019s that?\u00a0 Reactor design studies by large and prestigious universities and corporations have all come to the conclusion that these magnetic fusion beasts will be able to produce electricity at least as cheaply as the competition?\u00a0 I don\u2019t think so.\u00a0 I\u2019ve participated in just such a government-funded study, conducted by a major corporation as prime contractor, with several other prominent universities and corporations participating as subcontractors.\u00a0 I\u2019m familiar with the methodology used in several others.\u00a0 In general, it\u2019s possible to make the cost electricity come out at whatever figure you choose, within reason, using the most approved methods and the most sound project management and financial software.\u00a0 If the government is funding the work, it can be safely assumed that they don\u2019t want to hear something like, \u201cFuggedaboudit, this thing will be way too expensive to build and run.\u201d\u00a0 That would make the office that funded the work look silly, and the fusion researchers involved in the design look like welfare queens in white coats.\u00a0 The \u201cright\u201d cost numbers will always come out of these studies in the end.<\/p>\n

I submit that a better way to come up with a cost estimate is to use a little common sense.\u00a0 Do you really think that a commercial power company will be able to master the intricacies of tritium production and extraction from the vicinity of a highly radioactive reaction chamber at anywhere near the cost of, say, wind and solar combined with next generation nuclear reactors for baseload power?\u00a0 If you do, you\u2019re a great deal more optimistic than me.\u00a0 W7-X cost a billion euros.\u00a0 ITER is slated to cost 13 billion, and will likely come in at well over that.\u00a0 With research money hard to come by in Europe for much worthier projects, throwing amounts like that down a rat hole doesn\u2019t seem like a good plan.<\/p>\n

All this may come as a disappointment to fusion enthusiasts.\u00a0 On the other hand, you may want to consider the fact that, if fusion had been easy, we would probably have managed to blow ourselves up with pure fusion weapons by now.\u00a0 Beyond that, you never know when some obscure genius might succeed in pulling a rabbit out of their hat in the form of some novel confinement scheme.\u00a0 Several companies claim they have sure-fire approaches that are so good they will be able to dispense with tritium entirely in favor of more plentiful, naturally occurring isotopes.\u00a0 See, for example, here<\/a>, here<\/a>, and here,<\/a> and the summary at the Next Big Future <\/a>website.\u00a0 I\u2019m not optimistic about any of them, either, but you never know.<\/p>\n

\"Stellarator\"<\/a><\/p>\n

\n\t\t\t\t\tTweet<\/a>\n\t\t\t\t<\/div><\/div>","protected":false},"excerpt":{"rendered":"

According to an article that just appeared in Science magazine, scientists in Germany have completed building a stellarator by the name of Wendelstein 7-X (W7-X), and are seeking regulatory permission to turn the facility on in November.\u00a0 If you can’t get past the Science paywall, here’s an article in the popular media with\u00a0some links.\u00a0 Like … Continue reading “Another Fusion White Elephant Sighted in Germany”<\/span><\/a><\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"_jetpack_newsletter_access":"","_jetpack_dont_email_post_to_subs":false,"_jetpack_newsletter_tier_id":0,"_jetpack_memberships_contains_paywalled_content":false,"_jetpack_feature_clip_id":0,"_jetpack_memberships_contains_paid_content":false,"footnotes":"","jetpack_publicize_message":"","jetpack_publicize_feature_enabled":true,"jetpack_social_post_already_shared":true,"jetpack_social_options":{"image_generator_settings":{"template":"highway","default_image_id":0,"font":"","enabled":false},"version":2},"jetpack_post_was_ever_published":false},"categories":[37,78,23,33],"tags":[121,342],"class_list":["post-4676","post","type-post","status-publish","format-standard","hentry","category-energy","category-fusion-energy","category-nuclear-energy","category-technology","tag-fusion-energy-2","tag-magnetic-fusion"],"jetpack_publicize_connections":[],"jetpack_shortlink":"https:\/\/wp.me\/pwEq0-1dq","jetpack_sharing_enabled":true,"jetpack_featured_media_url":"","_links":{"self":[{"href":"https:\/\/helian.net\/blog\/wp-json\/wp\/v2\/posts\/4676","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/helian.net\/blog\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/helian.net\/blog\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/helian.net\/blog\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/helian.net\/blog\/wp-json\/wp\/v2\/comments?post=4676"}],"version-history":[{"count":2,"href":"https:\/\/helian.net\/blog\/wp-json\/wp\/v2\/posts\/4676\/revisions"}],"predecessor-version":[{"id":4679,"href":"https:\/\/helian.net\/blog\/wp-json\/wp\/v2\/posts\/4676\/revisions\/4679"}],"wp:attachment":[{"href":"https:\/\/helian.net\/blog\/wp-json\/wp\/v2\/media?parent=4676"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/helian.net\/blog\/wp-json\/wp\/v2\/categories?post=4676"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/helian.net\/blog\/wp-json\/wp\/v2\/tags?post=4676"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}