1 00:00:00,129 --> 00:00:03,228 Have you ever been in an argument about nuclear power? 2 00:00:03,579 --> 00:00:06,544 We have, and we found it frustrating and confusing, 3 00:00:06,544 --> 00:00:09,127 so let’s try and get to grips with this topic. 4 00:00:16,014 --> 00:00:18,122 It all started in the 1940s. 5 00:00:18,249 --> 00:00:21,242 After the shock and horror of the war and the use of the atomic bomb, 6 00:00:21,242 --> 00:00:24,914 nuclear energy promised to be a peaceful spin-off of the new technology, 7 00:00:24,914 --> 00:00:26,996 helping the world get back on its feet. 8 00:00:27,326 --> 00:00:29,831 Everyone’s imagination was running wild. 9 00:00:30,021 --> 00:00:31,816 Would electricity become free? 10 00:00:32,046 --> 00:00:34,503 Could nuclear power help settle the Antarctic? 11 00:00:34,743 --> 00:00:38,310 Would there be nuclear-powered cars, planes, or houses? 12 00:00:38,840 --> 00:00:41,893 It seemed that this was just a few years of hard work away. 13 00:00:42,333 --> 00:00:45,739 One thing was certain: the future was atomic. 14 00:00:46,319 --> 00:00:49,787 Just a few years later, there was a sort of atomic age hangover; 15 00:00:49,787 --> 00:00:54,877 as it turned out, nuclear power was very complicated and very expensive. 16 00:00:55,237 --> 00:00:58,239 Turning physics into engineering was easy on paper, 17 00:00:58,239 --> 00:01:00,059 but hard in real life. 18 00:01:00,139 --> 00:01:03,795 Also, private companies thought that nuclear power was much too risky 19 00:01:03,795 --> 00:01:08,198 as an investment; most of them would much rather stick with gas, coal, and oil. 20 00:01:08,628 --> 00:01:10,923 But there were many people who didn’t just want to abandon 21 00:01:10,923 --> 00:01:14,122 the promise of the atomic age; an exciting new technology, 22 00:01:14,122 --> 00:01:16,566 the prospect of enormously cheap electricity, 23 00:01:16,566 --> 00:01:20,070 the prospect of being independent of oil and gas imports, 24 00:01:20,070 --> 00:01:24,237 and, in some cases, a secret desire to possess atomic weapons 25 00:01:24,237 --> 00:01:27,133 provided a strong motivation to keep going. 26 00:01:27,633 --> 00:01:32,285 Nuclear power’s finest hour finally came in the early 1970s, when 27 00:01:32,285 --> 00:01:36,305 war in the Middle East caused oil prices to skyrocket worldwide. 28 00:01:36,435 --> 00:01:40,656 Now, commercial interest and investment picked up at a dazzling pace. 29 00:01:40,906 --> 00:01:43,961 More than half of all the nuclear reactors in the world were built 30 00:01:43,961 --> 00:01:46,315 between 1970 and 1985. 31 00:01:46,570 --> 00:01:49,821 But which type of reactor to build, given how many different types 32 00:01:49,821 --> 00:01:50,985 there were to choose from? 33 00:01:51,445 --> 00:01:53,966 A surprising underdog candidate won the day: 34 00:01:53,966 --> 00:01:55,607 the light water reactor. 35 00:01:55,997 --> 00:01:59,698 It wasn’t very innovative, and it wasn’t too popular with scientists, 36 00:01:59,698 --> 00:02:01,933 but it had some decisive advantages: 37 00:02:01,933 --> 00:02:06,013 it was there, it worked, and it wasn’t terribly expensive. 38 00:02:06,413 --> 00:02:08,645 So, what does a light water reactor do? 39 00:02:09,155 --> 00:02:11,565 Well, the basic principle is shockingly simple: 40 00:02:11,565 --> 00:02:14,924 it heats up water using an artificial chain reaction. 41 00:02:15,534 --> 00:02:18,657 Nuclear fission releases several million times more energy 42 00:02:18,657 --> 00:02:20,274 than any chemical reaction could. 43 00:02:20,754 --> 00:02:24,413 Really heavy elements on the brink of stability, like uranium-235, 44 00:02:24,413 --> 00:02:26,251 get bombarded with neutrons. 45 00:02:26,721 --> 00:02:29,968 The neutron is absorbed, but the result is unstable. 46 00:02:30,328 --> 00:02:34,107 Most of the time, it immediately splits into fast-moving lighter elements, 47 00:02:34,107 --> 00:02:38,606 some additional free neutrons, and energy in the form of radiation. 48 00:02:38,606 --> 00:02:42,426 The radiation heats the surrounding water, while the neutrons repeat the process 49 00:02:42,426 --> 00:02:45,574 with other atoms, releasing more neutrons and radiation 50 00:02:45,574 --> 00:02:50,242 in a closely controlled chain reaction, very different from the fast, destructive 51 00:02:50,242 --> 00:02:52,759 runaway reaction in an atomic bomb. 52 00:02:53,039 --> 00:02:57,893 In our light water reactor, a moderator is needed to control the neutrons’ energy. 53 00:02:58,123 --> 00:03:02,445 Simple, ordinary water does the job, which is very practical, since water’s used 54 00:03:02,445 --> 00:03:04,213 to drive the turbines anyway. 55 00:03:04,333 --> 00:03:07,804 The light water reactor became prevalent because it’s simple and cheap. 56 00:03:08,194 --> 00:03:12,184 However, it’s neither the safest, most efficient, nor technically elegant 57 00:03:12,184 --> 00:03:13,296 nuclear reactor. 58 00:03:13,616 --> 00:03:16,848 The renewed nuclear hype lasted barely a decade, though; 59 00:03:16,848 --> 00:03:21,002 in 1979, the Three Mile Island nuclear plant in Pennsylvania 60 00:03:21,002 --> 00:03:24,100 barely escaped a catastrophe when its core melted. 61 00:03:24,310 --> 00:03:28,557 In 1986, the Chernobyl catastrophe directly threatened Central Europe 62 00:03:28,557 --> 00:03:32,907 with a radioactive cloud, and in 2011 the drawn-out Fukushima disaster 63 00:03:32,907 --> 00:03:35,244 sparked new discussions and concerns. 64 00:03:35,647 --> 00:03:40,621 While in the 1980s 218 new nuclear power reactors went live, 65 00:03:40,621 --> 00:03:45,663 their number and nuclear’s global share of electricity production has stagnated 66 00:03:45,663 --> 00:03:47,447 since the end of the ’80s. 67 00:03:47,807 --> 00:03:49,544 So what’s the situation today? 68 00:03:49,904 --> 00:03:54,359 Today, nuclear energy meets around 10% of the world’s energy demand. 69 00:03:54,619 --> 00:03:58,860 There are about 439 nuclear reactors in 31 countries. 70 00:03:59,180 --> 00:04:02,408 About 70 new reactors are under construction in 2015, 71 00:04:02,408 --> 00:04:05,089 most of them in countries which are growing quickly. 72 00:04:05,259 --> 00:04:09,403 All in all, 116 new reactors are planned worldwide. 73 00:04:09,773 --> 00:04:14,377 Most nuclear reactors were built more than 25 years ago with pretty old technology. 74 00:04:14,727 --> 00:04:18,468 More than 80% are various types of light water reactor. 75 00:04:18,828 --> 00:04:23,226 Today, many countries are faced with a choice: the expensive replacement of 76 00:04:23,226 --> 00:04:27,368 the aging reactors, possibly with more efficient, but less tested models, 77 00:04:27,368 --> 00:04:31,475 or a move away from nuclear power towards newer or older technology 78 00:04:31,475 --> 00:04:34,177 with different cost and environmental impacts. 79 00:04:34,427 --> 00:04:36,963 So, should we use nuclear energy? 80 00:04:37,433 --> 00:04:40,933 The pro and contra arguments will be presented here next week. 81 00:04:41,173 --> 00:04:43,140 Subscribe, and then you won’t miss it! 82 00:04:44,530 --> 00:04:47,265 Our channel has a new sponsor: Audible.com. 83 00:04:47,475 --> 00:04:50,563 If you use the URL , 84 00:04:50,563 --> 00:04:53,916 you can get a free audiobook and support our channel. 85 00:04:54,106 --> 00:04:58,927 Producing our videos takes a lot of time, and we fill a lot of it by listening 86 00:04:58,927 --> 00:05:00,216 to audiobooks. 87 00:05:00,216 --> 00:05:02,234 For a really entertaining book, we recommend 88 00:05:02,234 --> 00:05:04,321 “Into Thin Air” by Jon Krakauer. 89 00:05:04,321 --> 00:05:07,924 He’s a great writer, and the story is really absorbing and true. 90 00:05:08,224 --> 00:05:11,690 Go to to get the book for free. 91 00:05:12,020 --> 00:05:15,817 Thanks a lot to Audible for supporting our channel and to you for watching!