WEBVTT - How Does Plutonium Work? 0:00:01.800 --> 0:00:04.320 Welcome to brain Stuff, a production of I Heart Radio, 0:00:06.600 --> 0:00:13.360 Hey brain Stuff Lauren Bogbaum. Here. On August, about eleven 0:00:13.440 --> 0:00:17.160 billion miles away from the Sun, the NASA probe Voyager 0:00:17.280 --> 0:00:21.479 one left the heliosphere, boldly going where no man made 0:00:21.520 --> 0:00:25.759 object had gone before. By crossing that boundary, Voyager one 0:00:25.840 --> 0:00:29.520 traveled beyond the Solar System and entered interstellar space, a 0:00:29.720 --> 0:00:34.280 historic first. If you look at the bottom row of 0:00:34.320 --> 0:00:37.640 a traditional periodic table, you'll find the element that made 0:00:37.680 --> 0:00:43.760 this cosmic adventure possible. Plutonium. First identified in the nineteen forties, 0:00:43.800 --> 0:00:47.840 Plutonium has been used for both creative and destructive purposes. 0:00:48.520 --> 0:00:52.240 The late physicist John Goffman once called plutonium the element 0:00:52.360 --> 0:00:56.639 of the Lord of Hell. Every atom of plutonium contains 0:00:56.760 --> 0:01:00.400 ninety four protons on the periodic table. This places it 0:01:00.440 --> 0:01:04.040 after uranium with its ninety two protons, and neptunium with 0:01:04.200 --> 0:01:08.560 ninety three. Uranium was first identified and named after the planet, 0:01:08.640 --> 0:01:11.600 which was named after the ancient god Yuranus, back in 0:01:11.920 --> 0:01:16.840 seventy nine. The researchers who identified neptunium in nineteen forty 0:01:16.920 --> 0:01:20.480 followed suit, and later that year so did Glenn Seaborg 0:01:20.560 --> 0:01:25.000 and his co workers at Berkeley Laboratory when they discovered plutonium. 0:01:25.200 --> 0:01:28.200 Just ten years earlier, astronomers had observed a new dwarf 0:01:28.240 --> 0:01:31.800 planet near Neptune to honor the Roman god of the underworld. 0:01:31.959 --> 0:01:35.759 It was dubbed Pluto, and plutonium derives its name from 0:01:35.800 --> 0:01:41.080 that heavenly body. Originally, Seaborgan Company were able to produce 0:01:41.160 --> 0:01:45.560 plutonium by using a particle accelerator at Berkeley. With this device, 0:01:45.720 --> 0:01:49.640 particles called deuterons were fired at a uranium sample. The 0:01:49.720 --> 0:01:53.680 experiment created a small amount of neptunium, which then became 0:01:53.720 --> 0:02:00.000 plutonium through a decaying process. But the first waveable plutoniums 0:02:00.000 --> 0:02:04.400 sample was created at the University of Chicago on August two. 0:02:05.280 --> 0:02:11.680 By that point, some parties had recognized the elements military potential. Okay, 0:02:11.840 --> 0:02:15.440 let's talk about isotopes. So atoms of any given element 0:02:15.520 --> 0:02:18.560 will always have the same number of protons in their nucleus, 0:02:18.760 --> 0:02:22.600 but the number of neutrons can vary. These variations are 0:02:22.639 --> 0:02:27.000 called isotopes of an element. After one of uranium's isotopes, 0:02:27.360 --> 0:02:30.680 uranium two thirty five, was identified as a potential fuel 0:02:30.680 --> 0:02:36.359 source for nuclear weapons, plutonium entered the conversation too. Plutonium 0:02:36.440 --> 0:02:39.360 was the key ingredient in the first atomic bomb explosion 0:02:39.480 --> 0:02:43.880 on Earth, which took place July sixty five. It was 0:02:43.880 --> 0:02:45.840 in New Mexico, and it was strong enough to be 0:02:45.880 --> 0:02:48.000 felt a hundred miles or more than a hundred and 0:02:48.040 --> 0:02:51.680 fifty kilometers away. It was part of the Manhattan Project's 0:02:51.760 --> 0:02:56.240 top secret Trinity nuclear test, and no uranium based weapons 0:02:56.280 --> 0:03:01.079 were deployed for the experiment. However, uranium two thirty five 0:03:01.320 --> 0:03:03.480 was the fuel in the weapon that the United States 0:03:03.600 --> 0:03:06.560 used to destroy Hiroshima, Japan on August six of nine. 0:03:08.080 --> 0:03:10.799 Plutonium was the fuel in the bomb that destroyed Nagasaki 0:03:10.840 --> 0:03:14.720 three days later, killing tens of thousands of civilians fatally, 0:03:14.760 --> 0:03:18.480 injuring many more, and effectively ending World War Two and 0:03:18.639 --> 0:03:23.639 kicking off the Cold War. But beyond its use in weapons, 0:03:24.040 --> 0:03:28.079 is plutonium dangerous. It is both chemically toxic and emits 0:03:28.120 --> 0:03:31.760 ionizing radiation, but you'll likely never be exposed to it. 0:03:31.760 --> 0:03:34.720 It only occurs in trace amounts in nature when certain 0:03:34.760 --> 0:03:38.600 types of uranium decay. It could possibly be released into 0:03:38.600 --> 0:03:41.400 the environment via an industrial plant, but there are many 0:03:41.400 --> 0:03:44.680 safeguards against this. If you did encounter some, it could 0:03:44.720 --> 0:03:46.960 burn your skin if you touched it, but the main 0:03:47.080 --> 0:03:49.640 danger would be from inhaling small particles of it that 0:03:49.680 --> 0:03:52.120 could get taken up by your system and transferred to 0:03:52.200 --> 0:03:55.320 your liver and bones, where it might eventually cause cancer. 0:03:56.400 --> 0:03:58.880 Even though it's a dangerous element, plutonium is far from 0:03:58.960 --> 0:04:02.000 being the most toxic substance known to man, as activist 0:04:02.040 --> 0:04:06.320 Ralph Nader once proclaimed, and today more than one third 0:04:06.360 --> 0:04:09.920 of the energy produced at nuclear power plants comes from plutonium. 0:04:10.080 --> 0:04:13.120 The United States, however, doesn't have any facilities that rely 0:04:13.240 --> 0:04:17.760 on plutonium for energy. The most common plutonium isotope formed 0:04:17.760 --> 0:04:20.880 in a nuclear reactor is plutonium two thirty nine, which 0:04:20.920 --> 0:04:24.440 is created by neutron capture from depleted uranium two thirty eight. 0:04:25.120 --> 0:04:27.640 When used for fission, plutonium two thirty nine can have 0:04:27.680 --> 0:04:30.599 as much energy as enriched uranium two thirty five, which 0:04:30.680 --> 0:04:35.960 is also used in nuclear weapons. Historically, another plutonium isotope, 0:04:36.000 --> 0:04:39.000 plutonium two thirty eight, was used to power the batteries 0:04:39.040 --> 0:04:42.800 in some commercial pacemakers. Those medical devices went out of 0:04:42.839 --> 0:04:47.560 style as lithium powered alternatives hit the market, but in 0:04:47.600 --> 0:04:52.560 the final frontier, plutonium remains a valuable commodity. For the 0:04:52.640 --> 0:04:54.960 article this episode is based on, has to Work Spook 0:04:55.040 --> 0:04:57.479 via email with Peter C. Burns, a chemist at the 0:04:57.520 --> 0:05:01.800 University of Notre Dame. He said the most significant, lesser 0:05:01.839 --> 0:05:05.920 known use of plutonium is for power generation during space exploration. 0:05:06.440 --> 0:05:08.960 Plutonium two thirty eight emits a lot of heat when 0:05:08.960 --> 0:05:12.440 it undergoes radioactive decay, and this heat can be used 0:05:12.440 --> 0:05:17.360 in a thermoelectric generator to produce electricity. That's just one 0:05:17.440 --> 0:05:20.760 quality that makes this isotope very attractive to engineers working 0:05:20.800 --> 0:05:24.159 for space agencies. There's also its half life, which is 0:05:24.160 --> 0:05:26.000 how long it takes for half of the atoms in 0:05:26.000 --> 0:05:29.279 a given sample to decay and transform into something else. 0:05:30.040 --> 0:05:33.080 With a respectable half life of eighty eight years, plutonium 0:05:33.120 --> 0:05:35.760 two thirty eight can keep rovers and space probes running 0:05:35.760 --> 0:05:39.560 for decades on end far away from the Sun in 0:05:39.640 --> 0:05:42.560 places where the stars raise are weak and dim, the 0:05:42.600 --> 0:05:46.240 solar powered satellites aren't going to perform that well, and 0:05:46.520 --> 0:05:49.800 Mars rovers that depend on sunlight, like the now defunct 0:05:49.800 --> 0:05:52.720 Opportunity Rover, have had to contend with the dust from 0:05:52.760 --> 0:05:56.760 passing storms that can smother their panels and impede battery function. 0:05:58.000 --> 0:06:00.640 For these reasons, plutonium two thirty eight is a great 0:06:00.640 --> 0:06:04.760 fit for both Martian and deep space exploration. So far, 0:06:05.000 --> 0:06:07.839 plutonium two thirty eight has powered at least thirty U 0:06:07.920 --> 0:06:11.479 S space vehicles. The Perseverance Rover, the touchdown on the 0:06:11.480 --> 0:06:15.600 Red Planet in February, has a generator fueled by plutonium 0:06:15.640 --> 0:06:19.000 two thirty eight. This so do far flung spacecrafts like 0:06:19.200 --> 0:06:21.960 Voyager one and Voyager two, which have been touring the 0:06:22.000 --> 0:06:31.280 Solar System and beyond since nine Today's episode is based 0:06:31.320 --> 0:06:34.680 on the article radioactive, a profile of the element plutonium 0:06:34.720 --> 0:06:37.000 on how stuff works dot com, written by Mark Vancini. 0:06:37.480 --> 0:06:39.719 Brain Stuff is production of Our Heart Radio in partnership 0:06:39.720 --> 0:06:41.520 with how stuff works dot com, and it's produced by 0:06:41.520 --> 0:06:44.840 Tyler Klang. 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