{"id":3005,"date":"2012-05-06T17:36:08","date_gmt":"2012-05-06T22:36:08","guid":{"rendered":"http:\/\/helian.net\/blog\/?p=3005"},"modified":"2012-05-06T17:37:55","modified_gmt":"2012-05-06T22:37:55","slug":"nuclear-power-thorium-and-the-role-of-government","status":"publish","type":"post","link":"https:\/\/helian.net\/blog\/2012\/05\/06\/us-politics\/nuclear-power-thorium-and-the-role-of-government\/","title":{"rendered":"Nuclear Power, Thorium, and the Role of Government"},"content":{"rendered":"

Nuclear power is an attractive candidate for meeting our future energy needs.\u00a0 Nuclear plants do not release greenhouse gases.\u00a0 They release significantly less radiation into the environment than coal plants, because coal contains several parts per million of radioactive thorium and uranium<\/a>.\u00a0 They require far less space and are far more reliable\u00a0than alternative energy sources such as wind and solar.\u00a0 In spite of some of the worst accidents imaginable due to human error and natural disasters, we have not lost any cities or\u00a0suffered any mass casualties,\u00a0and the horrific “China Syndrome” scenarios invented by the self-appointed saviors of mankind have proven to be\u00a0fantasies.\u00a0\u00a0That is not to say nuclear power is benign.\u00a0 It is just more benign than any of the currently available alternatives.\u00a0 The main problem with nuclear is not that it is unsafe, but that it is being ill-used.\u00a0 In this case, government could actually be helpful.\u00a0 Leadership and political will could put nuclear on a better track.<\/p>\n

To understand why, it is necessary to know a few things about nuclear fuel, and how it “burns.”\u00a0 Bear with me while I present a brief\u00a0tutorial in nuclear engineering.\u00a0 Nuclear energy is released by nuclear fission, or the splitting of heavy elements into two or more lighter ones.\u00a0 This doesn’t usually happen spontaneously.\u00a0\u00a0Before a heavy element can undergo fission,\u00a0an amount of energy above a certain threshold must first be delivered to\u00a0its nucleus.\u00a0 How does this\u00a0happen?\u00a0 Imagine a deep well.\u00a0 If you drop a\u00a0bowling ball into the well,\u00a0it will cause a large splash when it hits the water.\u00a0 It does so because it has been accelerated by the force of gravity.\u00a0 A heavy nucleus is something like a well,\u00a0but things don’t fall into it because of gravity.\u00a0 Instead, it relies on the strong force, which is very short range, but vastly more powerful than gravity.\u00a0 The role of “bowling ball” can be played by a neutron.\u00a0 If one happens along and gets close enough to fall into the strong force\u00a0“well,” it will also cause a “splash,” releasing energy as it is bound to the heavy element’s nucleus, just as the real bowling ball is “bound” in the\u00a0water well\u00a0until someone fishes it out.\u00a0 This “splash,” or release of energy, causes the\u00a0heavy nucleus to “jiggle,” much like an unstable drop of water.\u00a0\u00a0In one naturally occurring isotope – uranium with an atomic weight of 235 – this “jiggle” is so violent that it can cause the “drop of water” to split apart, or fission.<\/p>\n

There are other isotopes of uranium.\u00a0 All of them have 92 protons in their nucleus, but can have varying numbers of neutrons.\u00a0\u00a0The nucleus of\u00a0uranium 235, or U235, has 92 protons and 143 protons, adding up to a total of 235.\u00a0 Unfortunately, U235 is only 0.7% of natural uranium.\u00a0 Almost all the rest is U238, which has 92 protons and 146 neutrons.\u00a0 When a neutron falls into the U238 “well,” the “splash” isn’t big enough to cause fission, or at least not unless the neutron had a lot of energy to begin with, as if the “bowling ball” had been shot from a cannon.\u00a0 As a result, U238 can’t act as the fuel in a nuclear reactor.\u00a0 Almost all the nuclear reactors in operation today simply burn that 0.7% of\u00a0U235\u00a0and store what’s left over as radioactive waste.\u00a0 Unfortunately, that’s an extremely inefficient and wasteful use of the available fuel resources.<\/p>\n

To understand why, it’s necessary to understand something about what happens to the neutrons in a reactor that keep the nuclear chain reaction going.\u00a0 First of all, where do they come from?\u00a0 Well, each fission releases more neutrons.\u00a0 The exact number depends on how fast the neutron that caused the fission was going, and what isotope underwent fission.\u00a0 If enough are released to cause, on average, one more fission, then the resulting chain reaction will continue until the fuel is used up.\u00a0 Actually, two neutrons, give or take, are released in each fission.\u00a0 However, not all of them cause another fission.\u00a0 Some escape the fuel region and are lost.\u00a0 Others are absorbed in the fuel material.\u00a0 That’s where things get interesting.<\/p>\n

Recall that, normally, most of the fuel in a reactor isn’t U235, but the more common isotope, U238.\u00a0 When U238 absorbs a neutron, it forms U239, which quickly decays to neptunium 239 and then plutonium 239.\u00a0 Now it just so happens that plutonium 239, or Pu239, will also fission if a neutron “falls into its well,” just like U235.\u00a0 In other words, if enough neutrons were available, the reactor could actually produce more fuel, in the form of Pu239, than it consumes, potentially burning up most of the U238 as well as the U235.\u00a0 This is referred to as the “breeding” of nuclear fuel.\u00a0 Instead of just lighting the U235 “match” and letting it burn out, it would be used to light and burn the entire U238 “log.”\u00a0 Unfortunately, there are not enough neutrons in normal nuclear reactors to breed more fuel than is consumed.\u00a0 Such reactors have, however, been built, both in the United States and other countries, and have been safely operated for periods of many years.<\/p>\n

Plutonium breeders aren’t the only feasible type.\u00a0 In addition to U235 and\u00a0Pu239, another isotope will also fission if a neutron falls into its “well” –\u00a0uranium 233.\u00a0 Like Pu239, U233\u00a0doesn’t occur in nature.\u00a0 However, it can be “bred,” just like Pu239, from another element that does occur in nature, and is actually more common than uranium – thorium.\u00a0 I’ve had a few critical things to say about some of the popular science articles I’ve seen on thorium lately, but my criticisms were directed at inaccuracies in the articles, not at thorium technology itself.\u00a0 Thorium breeders actually have some important advantages over\u00a0plutonium.\u00a0 When U233 fissions, it produces more neutrons than Pu239, and it does so in a “cooler” neutron spectrum, where the average neutron energy is much lower, making the reactor significantly easier to control.\u00a0 These extra neutrons could not only breed more fuel.\u00a0 They could also be used to burn up the\u00a0transuranic elements – those beyond uranium on the table of the elements – that\u00a0are produced in conventional nuclear reactors, and account for the lion’s share of the long-lived radioactive waste.\u00a0 This would be a huge advantage.\u00a0 Destroy the transuranics, and the residual radioactivity from a reactor would be less than that of the original ore, potentially in a few hundred years, rather than many thousands.<\/p>\n

Thorium breeders have other potentially important advantages.\u00a0 The fuel material could be circulated through the core in the form of a liquid, suspended in a special “salt” material<\/a>.\u00a0 Of course, this would eliminate the danger of a fuel meltdown.\u00a0 In the event of an accident like the one at Fukushima, the fuel would simply be allowed to run into a holding basin, where it would be sub-critical and cool quickly.\u00a0 Perhaps more importantly, the United States has the biggest proven reserves of thorium on the planet.<\/p>\n

Breeders aren’t the only reactor types that hold great promise for meeting our future energy needs.\u00a0 High temperature gas cooled reactors would produce gas heated to high temperature in addition to electricity.\u00a0 This could be used to produce hydrogen gas via electrolysis, which is much more efficient at such high temperatures.\u00a0 When hydrogen burns, it produces only water.\u00a0 Such reactors could also be built over the massive oil shale deposits in the western United States.\u00a0 The hot gas could then be used to efficiently extract oil from the shale “in situ” without the need to mine it.\u00a0 It is estimated that the amount of oil that could be economically recovered in this way from the Green River Basin deposits<\/a> in Utah, Wyoming and Colorado alone is three times greater than the oil reserves of Saudi Arabia.<\/p>\n

Will any of this happen without government support and leadership?\u00a0 Not any time soon.\u00a0 The people who build nuclear reactors expect to make a profit, and the easiest way to make a profit is to build more conventional reactors of the type we already have.\u00a0 Raise the points I’ve mentioned above, and they’ll simply tell you that there’s plenty of cheap\u00a0uranium around and therefore no need to breed more fuel, the radioactive danger of transuranics has been much exaggerated, etc., etc.\u00a0 All these meretricious arguments make sense if your goal is to make a profit in the short run.\u00a0 They make no sense at all if you have any concern for the energy security and welfare\u00a0of future generations.<\/p>\n

Unless the proponents of controlled fusion\u00a0or solar and other forms of alternative energy manage to pull a rabbit out of their collective hats,\u00a0I suspect we will eventually adopt breeder technology.\u00a0 The question is when.\u00a0 After we have finally burnt\u00a0our last\u00a0reserves of fossil fuel?\u00a0 After we have used up all our precious reserves of U238 by scattering it hither and yon in the form of “depleted uranium” munitions?\u00a0 The longer we wait, the harder and more expensive it will become to develop a breeder economy.\u00a0 It would be well if, in this unusual case, government stepped in and did what it is theoretically supposed to do; lead.<\/p>\n

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Nuclear power is an attractive candidate for meeting our future energy needs.\u00a0 Nuclear plants do not release greenhouse gases.\u00a0 They release significantly less radiation into the environment than coal plants, because coal contains several parts per million of radioactive thorium and uranium.\u00a0 They require far less space and are far more reliable\u00a0than alternative energy sources … Continue reading “Nuclear Power, Thorium, and the Role of Government”<\/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":false,"jetpack_social_options":{"image_generator_settings":{"template":"highway","default_image_id":0,"font":"","enabled":false},"version":2},"jetpack_post_was_ever_published":false},"categories":[72,37,43,52,23,100,13],"tags":[],"class_list":["post-3005","post","type-post","status-publish","format-standard","hentry","category-depleted-uranium","category-energy","category-environment","category-global-warming","category-nuclear-energy","category-thorium","category-us-politics"],"jetpack_publicize_connections":[],"jetpack_shortlink":"https:\/\/wp.me\/pwEq0-Mt","jetpack_sharing_enabled":true,"jetpack_featured_media_url":"","_links":{"self":[{"href":"https:\/\/helian.net\/blog\/wp-json\/wp\/v2\/posts\/3005","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=3005"}],"version-history":[{"count":6,"href":"https:\/\/helian.net\/blog\/wp-json\/wp\/v2\/posts\/3005\/revisions"}],"predecessor-version":[{"id":3011,"href":"https:\/\/helian.net\/blog\/wp-json\/wp\/v2\/posts\/3005\/revisions\/3011"}],"wp:attachment":[{"href":"https:\/\/helian.net\/blog\/wp-json\/wp\/v2\/media?parent=3005"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/helian.net\/blog\/wp-json\/wp\/v2\/categories?post=3005"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/helian.net\/blog\/wp-json\/wp\/v2\/tags?post=3005"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}