1 00:00:00,520 --> 00:00:03,840 Speaker 1: Welcome to Brainstuff from house stuff works dot com, where 2 00:00:03,840 --> 00:00:15,760 Speaker 1: smart happens Him Marshall Brain with today's question, what is 3 00:00:16,000 --> 00:00:19,200 Speaker 1: high level nuclear waste and how are we dealing with 4 00:00:19,200 --> 00:00:23,520 Speaker 1: it today. Let's imagine that you own a nuclear power plant. 5 00:00:23,840 --> 00:00:26,920 Speaker 1: You're in a pretty good position these days because compared 6 00:00:26,920 --> 00:00:30,800 Speaker 1: to a coal fired power plant, your operation is very green. 7 00:00:31,440 --> 00:00:35,720 Speaker 1: You're producing lots of reliable electricity without releasing any carbon 8 00:00:35,760 --> 00:00:39,720 Speaker 1: dioxide into the atmosphere. You don't release any other pollutants 9 00:00:39,760 --> 00:00:43,400 Speaker 1: like sulfur or mercury into the atmosphere either, and you 10 00:00:43,520 --> 00:00:47,680 Speaker 1: also are not creating huge quantities of coal ash, which 11 00:00:47,680 --> 00:00:51,360 Speaker 1: at many power plants ends up being stored in immense lagoons. 12 00:00:51,880 --> 00:00:54,840 Speaker 1: These lagoons raise a lot of questions in terms of 13 00:00:54,880 --> 00:00:59,360 Speaker 1: long term stability, especially during floods. So as a nuclear 14 00:00:59,400 --> 00:01:03,560 Speaker 1: power plant operator, you are feeling pretty good. There is 15 00:01:03,680 --> 00:01:06,760 Speaker 1: in fact, only one fly in your ointment at the moment. 16 00:01:07,160 --> 00:01:10,240 Speaker 1: That fly is called high level nuclear waste, and it 17 00:01:10,280 --> 00:01:14,360 Speaker 1: appears every time you need to refuel your reactor. In fact, 18 00:01:14,440 --> 00:01:17,800 Speaker 1: the fly grows a little bigger with each refueling. Let's 19 00:01:17,840 --> 00:01:22,160 Speaker 1: take a look at how this high level nuclear waste works. First, 20 00:01:22,240 --> 00:01:25,319 Speaker 1: little background The goal of a nuclear reactor is to 21 00:01:25,400 --> 00:01:28,319 Speaker 1: create heat so that it can produce steam that drives 22 00:01:28,319 --> 00:01:31,760 Speaker 1: a generator. The nuclear fuel in the reactor creates the 23 00:01:31,800 --> 00:01:35,520 Speaker 1: heat through nuclear fission. The fuel consists of a mixture 24 00:01:35,560 --> 00:01:38,840 Speaker 1: of uranium two thirty five about four percent mixed with 25 00:01:38,959 --> 00:01:42,640 Speaker 1: uranium two thirty eight and other elements. The uranium two 26 00:01:42,680 --> 00:01:46,360 Speaker 1: thirty five is the actual fuel for the reactor. Each 27 00:01:46,400 --> 00:01:50,520 Speaker 1: fuel pellet containing the U two thirty five is very small, 28 00:01:50,560 --> 00:01:53,280 Speaker 1: about the size of your little toe, but it contains 29 00:01:53,360 --> 00:01:57,000 Speaker 1: the equivalent heat of perhaps a ton of coal. A 30 00:01:57,080 --> 00:02:00,960 Speaker 1: typical reactor contains several tons of these all it's arranged 31 00:02:00,960 --> 00:02:04,480 Speaker 1: in rods that fill the reactor core. The YouTube thirty 32 00:02:04,520 --> 00:02:08,360 Speaker 1: five sitting in the core undergoes a fission process. In 33 00:02:08,400 --> 00:02:12,080 Speaker 1: this process, it creates a tremendous amount of heat. In 34 00:02:12,120 --> 00:02:15,360 Speaker 1: a nuclear bomb, this heat is all released in less 35 00:02:15,400 --> 00:02:18,440 Speaker 1: than a second to create a gigantic explosion. In a 36 00:02:18,520 --> 00:02:21,840 Speaker 1: nuclear reactor, the heat is released gradually over the course 37 00:02:21,880 --> 00:02:24,240 Speaker 1: of a year or two to boil water that drives 38 00:02:24,280 --> 00:02:27,760 Speaker 1: the electric generators. At the end of that year or two, 39 00:02:27,919 --> 00:02:31,400 Speaker 1: the reactor shuts down for a month for refueling, and 40 00:02:31,600 --> 00:02:34,960 Speaker 1: the fly in the ointment appears, between one quarter and 41 00:02:35,080 --> 00:02:37,840 Speaker 1: one third of the fuel in the core is removed 42 00:02:37,880 --> 00:02:41,960 Speaker 1: and replaced with fresh fuel rods. Several tons of highly 43 00:02:42,080 --> 00:02:46,320 Speaker 1: radioactive material, also known as spent fuel or high level 44 00:02:46,400 --> 00:02:50,560 Speaker 1: nuclear waste, now has to be managed. The spent fuel 45 00:02:50,680 --> 00:02:53,520 Speaker 1: is still quite hot. It's so hot that it must 46 00:02:53,560 --> 00:02:57,000 Speaker 1: be stored in a spent fuel pool. It's like a 47 00:02:57,000 --> 00:03:00,800 Speaker 1: gigantic swimming pool fifty ft deep. The water is there 48 00:03:00,840 --> 00:03:04,079 Speaker 1: to absorb the heat. The depth of the water protects 49 00:03:04,080 --> 00:03:07,520 Speaker 1: people against the radioactivity of the fuel and also provides 50 00:03:07,560 --> 00:03:10,880 Speaker 1: a margin of safety. After several years in the pool, 51 00:03:11,160 --> 00:03:14,720 Speaker 1: the spent fuel has cooled enough to be manageable outside 52 00:03:14,760 --> 00:03:19,000 Speaker 1: of the spent fuel pool. However, it's still highly radioactive 53 00:03:19,000 --> 00:03:23,720 Speaker 1: and dangerous. In fact, it'll be highly radioactive and dangerous 54 00:03:23,760 --> 00:03:27,600 Speaker 1: for thousands and thousands of years. In the ideal case, 55 00:03:27,680 --> 00:03:30,280 Speaker 1: one of two things would happen at this point. One 56 00:03:30,360 --> 00:03:35,320 Speaker 1: possibility is recycling. A recycling facility could reprocess the spent 57 00:03:35,400 --> 00:03:38,760 Speaker 1: fuel to extract the usable uranium two thirty five and 58 00:03:38,880 --> 00:03:42,720 Speaker 1: the plutonium. It could then create a new fuel and 59 00:03:42,800 --> 00:03:46,800 Speaker 1: do so economically. However, in the United States, we do 60 00:03:46,840 --> 00:03:50,480 Speaker 1: not recycle nuclear fuel right now. The other option would 61 00:03:50,520 --> 00:03:54,920 Speaker 1: be to move the now cooled spent fuel into permanent storage. 62 00:03:55,120 --> 00:03:57,200 Speaker 1: The goal would be to keep it away from people 63 00:03:57,240 --> 00:04:00,760 Speaker 1: for thousands and thousands of years. The Yuck Amount Facility 64 00:04:00,760 --> 00:04:04,160 Speaker 1: in Nevada was the proposed site for such long term storage, 65 00:04:04,440 --> 00:04:07,840 Speaker 1: but that idea has been abandoned for now. So at 66 00:04:07,880 --> 00:04:11,760 Speaker 1: the moment, nuclear power plants store their cooled spent fuel 67 00:04:12,080 --> 00:04:16,760 Speaker 1: their high level nuclear waste in containers called dry casks. 68 00:04:16,800 --> 00:04:20,720 Speaker 1: These are typically strong steel cylinders that are then surrounded 69 00:04:20,720 --> 00:04:24,320 Speaker 1: in concrete. The combination of steel and concrete provides a 70 00:04:24,400 --> 00:04:28,039 Speaker 1: secure container and protection from the radioactivity of the spent 71 00:04:28,120 --> 00:04:32,400 Speaker 1: fuel inside the cask. These casks are stored on concrete 72 00:04:32,400 --> 00:04:36,120 Speaker 1: pads outside the reactor facility and will remain there until 73 00:04:36,160 --> 00:04:38,599 Speaker 1: the United States comes up with a better long term 74 00:04:38,640 --> 00:04:43,839 Speaker 1: solution for high level nuclear waste. Be sure to check 75 00:04:43,839 --> 00:04:46,960 Speaker 1: out our new video podcast, Stuff from the Future. Join 76 00:04:47,080 --> 00:04:49,560 Speaker 1: House to Work staff as we explore the most promising 77 00:04:49,640 --> 00:04:54,279 Speaker 1: and perplexing possibilities of tomorrow. The House to Worts I 78 00:04:54,360 --> 00:04:57,479 Speaker 1: find app has arrived. Download it today on iTunes.