WEBVTT - SYMHC Classics: Demon Core 0:00:02.560 --> 0:00:03.680 Happy Saturday. 0:00:04.400 --> 0:00:07.160 Coming up, we have an episode that has some parallels 0:00:07.200 --> 0:00:11.320 to our previous episode on the Demon Core. Both of 0:00:11.360 --> 0:00:14.680 these involved a nuclear incident, and both of them also 0:00:14.800 --> 0:00:18.000 have discussions of the Cold War rush to develop nuclear 0:00:18.040 --> 0:00:22.439 technologies that led to some dangerous shortcuts. This episode came 0:00:22.480 --> 0:00:29.240 out on October twelfth, twenty twenty. Enjoy Welcome to Stuff 0:00:29.240 --> 0:00:35.560 You Missed in History Class, a production of iHeartRadio. 0:00:38.960 --> 0:00:41.479 Hello, and welcome to the podcast. I'm Tracy B. 0:00:41.600 --> 0:00:43.400 Wilson, and I'm Holly Frye. 0:00:43.680 --> 0:00:45.280 My friend Adrian, who. 0:00:45.159 --> 0:00:48.600 Is a science educator, asked me years ago at this 0:00:48.720 --> 0:00:51.559 point whether we had ever thought about doing an episode 0:00:51.560 --> 0:00:55.480 on the Demon Core, which sounds terrifying, and I kept 0:00:55.520 --> 0:00:59.520 thinking it might make a good October episode because nuclear 0:00:59.560 --> 0:01:04.840 critical accidents can be terrifying, like they expose people to 0:01:05.240 --> 0:01:08.880 possibly lethal doses of radiation and just a fraction of 0:01:08.920 --> 0:01:12.959 a second, usually completely by surprise and before anybody can react, 0:01:12.959 --> 0:01:15.880 and then that leads to just a horrifying and gruesome 0:01:15.920 --> 0:01:21.119 and sometimes prolonged death. So then every October I kept 0:01:21.200 --> 0:01:23.480 moving on in other directions and not getting to the 0:01:23.520 --> 0:01:24.080 demon Core. 0:01:25.000 --> 0:01:25.880 Here it finally is. 0:01:26.800 --> 0:01:31.600 The Demon Core was a sphere of plutonium gallium alloy 0:01:31.800 --> 0:01:34.640 that the United States made for an atomic bomb during 0:01:34.680 --> 0:01:38.200 World War Two, and then after the war, researchers at 0:01:38.200 --> 0:01:43.160 Los Alamos National Laboratory had two separate fatal criticality accidents 0:01:43.160 --> 0:01:46.680 while working with it. Those accidents are also part of 0:01:46.720 --> 0:01:50.440 a greater history of criticality accidents, most of which took 0:01:50.480 --> 0:01:52.600 place in the nineteen fifties and sixties. So we're going 0:01:52.680 --> 0:01:57.520 to talk about that progression today just to set some expectations. 0:01:58.080 --> 0:02:01.600 Nuclear reactor melt down like the disasters at Three Mile 0:02:01.680 --> 0:02:05.000 Island and Chernobyl and Fukushima, those are a slightly different 0:02:05.040 --> 0:02:08.440 thing from what we're talking about today. Some of them 0:02:08.600 --> 0:02:11.880 could technically be classified as criticality accidents, but they're also 0:02:12.000 --> 0:02:14.360 just a little bit bigger than the topics that were 0:02:14.400 --> 0:02:17.400 focused on. So to make sense of how these incidents 0:02:17.400 --> 0:02:19.440 play out, we need to walk through a little bit 0:02:19.440 --> 0:02:23.760 of science history. In nineteen thirty two, James Chadwick discovered 0:02:23.760 --> 0:02:27.720 the uncharged sub atomic particle known as the neutron, and 0:02:27.800 --> 0:02:32.160 soon physicists were using neutrons to study atoms, including bombarding 0:02:32.240 --> 0:02:36.320 atomic nuclei with neutrons to study the results. It was 0:02:36.400 --> 0:02:40.239 through this work that ottohon Lee's Meiitner and Fritz Strassmann 0:02:40.360 --> 0:02:44.600 discovered nuclear fission in nineteen thirty eight. Hahn had been 0:02:44.600 --> 0:02:48.120 working with uranium samples that had been bombarded with neutrons, 0:02:48.160 --> 0:02:52.520 and for reasons that he couldn't really explain, barium isotopes 0:02:52.600 --> 0:02:56.680 started appearing in his samples as well. Meiitner and Strasman 0:02:56.880 --> 0:03:00.000 made the connection that barium has about half the time 0:03:00.320 --> 0:03:03.880 mass of uranium, so the uranium atoms were splitting into 0:03:03.919 --> 0:03:07.880 two roughly equal parts. The idea that an atom could 0:03:07.919 --> 0:03:10.880 split in this way had been suggested before, but it 0:03:11.000 --> 0:03:13.640 was not really taken seriously at the time because it 0:03:13.680 --> 0:03:18.560 seemed absolutely contrary to how people understood nuclear physics at 0:03:18.560 --> 0:03:22.760 that point. This breakdown of uranium into barium didn't answer 0:03:22.800 --> 0:03:26.480 all the questions, though Meitner also calculated that the two 0:03:26.680 --> 0:03:29.800 new barium nuclei would be slightly less massive than the 0:03:29.840 --> 0:03:34.760 original uranium nucleus, with the difference converted into energy. Atto 0:03:34.840 --> 0:03:37.520 Haan was awarded the Nobel Prize in Chemistry for the 0:03:37.560 --> 0:03:41.880 discovery of nuclear fission in nineteen forty four. Although Meiitner 0:03:41.920 --> 0:03:44.560 and Strassman were mentioned in the speech, they were not 0:03:44.640 --> 0:03:49.640 included in that award. Nuclear fission can happen spontaneously in 0:03:49.760 --> 0:03:52.680 the natural world, and the details can play out a 0:03:52.680 --> 0:03:56.000 little bit differently in different elements and isotopes, but in 0:03:56.120 --> 0:03:58.800 terms of what we're talking about today, it typically starts 0:03:58.800 --> 0:04:02.720 with neutrons. Neutrons interact with the atom's nucleus, causing it 0:04:02.720 --> 0:04:07.160 to split. That split releases one or more other neutrons, 0:04:07.200 --> 0:04:10.040 and in the right conditions, those neutrons can reach the 0:04:10.120 --> 0:04:14.240 nuclei of other nearby atoms, causing them to split. That 0:04:14.320 --> 0:04:17.840 can continue on in a chain reaction. If there's enough 0:04:17.880 --> 0:04:22.000 material in one place to support a regular, ongoing, self 0:04:22.000 --> 0:04:26.120 sustaining chain reaction, that's known as critical mass. In a 0:04:26.279 --> 0:04:30.599 supercritical mass, this chain reaction unfolds at an escalating rate 0:04:30.680 --> 0:04:34.000 instead of a steady one. It's not just about how 0:04:34.080 --> 0:04:37.839 much physical material is in one place, though. The volume 0:04:37.880 --> 0:04:42.240 of the material, it's geometry, its concentration, its surroundings, and 0:04:42.320 --> 0:04:46.080 other factors all play a part. As a hypothetical example, 0:04:46.200 --> 0:04:49.080 if you have a very thin sheet of uranium two 0:04:49.120 --> 0:04:51.880 thirty five, a lot of the neutrons that are released 0:04:51.960 --> 0:04:54.520 during fission are going to fly off into the surrounding 0:04:54.560 --> 0:04:58.320 air without hitting any uranium atoms. But if you have 0:04:58.360 --> 0:05:01.559 the same amount of uranium two thirty five packed into 0:05:01.600 --> 0:05:05.159 a tight sphere, the neutrons from the interior are far 0:05:05.200 --> 0:05:08.400 more likely to interact with other nuclei as they travel, 0:05:08.720 --> 0:05:12.599 potentially starting a chain reaction. So the elements that break 0:05:12.640 --> 0:05:16.080 down and these interactions are radioactive, and the products of 0:05:16.160 --> 0:05:21.280 fission are generally radioactive as well. The energy that's released 0:05:21.480 --> 0:05:24.200 during nuclear fission, which there can be a lot of, 0:05:24.720 --> 0:05:29.359 also includes ionizing radiation, and while ionizing radiation has some 0:05:29.440 --> 0:05:34.400 beneficial uses, it can also be incredibly destructive to living cells. 0:05:35.000 --> 0:05:39.520 Criticality accidents can expose people and objects to just enormous 0:05:39.560 --> 0:05:43.120 amounts of radiation in an instant, so facilities that handle 0:05:43.160 --> 0:05:46.400 these types of materials have to take a lot of 0:05:46.480 --> 0:05:50.160 precautions to protect people from radiation and to prevent an 0:05:50.200 --> 0:05:54.280 accidental criticality, which is sometimes also called a power excursion. 0:05:54.880 --> 0:05:57.960 This includes restrictions on how much material can be in 0:05:58.000 --> 0:06:02.040 a particular place and how its to be handled. Containers 0:06:02.080 --> 0:06:04.080 to hold the material have to be shaped in a 0:06:04.080 --> 0:06:07.960 way that is unfavorable for criticality and made of materials 0:06:07.960 --> 0:06:11.160 that won't reflect too many sub atomic particles. Back into 0:06:11.200 --> 0:06:14.800 the material, and people handling the material have to be 0:06:14.880 --> 0:06:19.120 trained on how to prevent criticality accidents. Some of this 0:06:19.320 --> 0:06:24.320 can be a little counterintuitive to outside observers. For example, 0:06:24.400 --> 0:06:28.040 if you saw some plutonium rods placed near each other 0:06:28.240 --> 0:06:31.160 in a way that could potentially lead to a criticality, 0:06:31.279 --> 0:06:35.120 your first instinct might be to move them apart so 0:06:35.160 --> 0:06:37.440 that they would not do that. But a person's own 0:06:37.600 --> 0:06:41.120 body can also reflect neutrons back at the material, so 0:06:41.200 --> 0:06:44.440 that very act of trying to prevent a criticality accident 0:06:44.520 --> 0:06:48.480 could actually wind up causing one instead. This is a 0:06:48.480 --> 0:06:52.000 real example. It happened at Los Alamos National Laboratory in 0:06:52.120 --> 0:06:55.279 August of twenty eleven after somebody made an arrangement of 0:06:55.320 --> 0:07:00.080 plutonium rods for a photo op. Fortunately, while what what 0:07:00.279 --> 0:07:03.719 happened was outside the bounds of safety guidelines, it did 0:07:03.760 --> 0:07:08.719 not cause a criticality accident. Because nuclear fission releases energy, 0:07:08.839 --> 0:07:12.920 its discovery had immediate and obvious implications for both energy 0:07:12.960 --> 0:07:17.160 production and warfare, and multiple nations started trying to develop 0:07:17.280 --> 0:07:21.040 nuclear reactors and atomic bombs. In the United States, the 0:07:21.080 --> 0:07:23.440 effort to develop an atomic bomb was code named the 0:07:23.480 --> 0:07:27.920 Manhattan Project, which also involved the construction of nuclear reactors 0:07:27.960 --> 0:07:32.160 to produce the necessary radioactive materials for the bomb. For 0:07:32.200 --> 0:07:36.239 the most part, the reactors converted naturally occurring uranium into 0:07:36.440 --> 0:07:40.880 uranium and plutonium fuel. Most of the natural uranium that 0:07:41.040 --> 0:07:43.960 was used in American projects during World War II was 0:07:44.040 --> 0:07:46.960 mined in what was then the Belgian Congo, and then 0:07:47.000 --> 0:07:50.080 after the war that source shifted to the Navajo Nation 0:07:50.400 --> 0:07:55.680 and surrounding areas. The environmental, human rights, and health consequences 0:07:55.720 --> 0:07:59.240 of these uranium mining operations, some of which are extreme, 0:07:59.280 --> 0:08:02.559 are still on going today. For example, there are still 0:08:02.760 --> 0:08:07.200 hundreds of abandoned uranium mines on or near the lands 0:08:07.200 --> 0:08:11.000 of multiple indigenous nations in the US, and even though 0:08:11.000 --> 0:08:14.520 the EPA has entered into settlements totaling one point seven 0:08:14.680 --> 0:08:19.480 billion dollars, those settlements covered cleanup for fewer than half 0:08:19.600 --> 0:08:22.800 of these mines, and almost none of them have actually 0:08:22.880 --> 0:08:26.520 been addressed at this point. Although nuclear research took place 0:08:26.560 --> 0:08:30.440 at multiple facilities around the country, the primary lamb for 0:08:30.480 --> 0:08:33.520 atomic bomb development in the US was in Los Alamos, 0:08:33.559 --> 0:08:38.199 New Mexico. Simultaneously, researchers had to figure out the technology 0:08:38.280 --> 0:08:41.040 for the bomb, produced the nuclear material to power it, 0:08:41.480 --> 0:08:44.520 and figure out how to handle that material safely without 0:08:44.640 --> 0:08:48.880 accidentally allowing it to go critical or supercritical, all while 0:08:48.920 --> 0:08:52.040 trying to create a weapon that was supposed to go supercritical. 0:08:52.679 --> 0:08:55.240 One of the bombs that was created through the Manhattan 0:08:55.280 --> 0:08:58.079 Project was known as Little Boy. Then it was detonated 0:08:58.080 --> 0:09:02.320 over Hiroshima, Japan, on August six, nineteen forty five. This 0:09:02.400 --> 0:09:06.800 bomb contained a subcritical mass of enriched uranium along with 0:09:06.880 --> 0:09:12.559 a subcritical uranium projectile. A gun fired the projectile into 0:09:12.559 --> 0:09:16.360 the mass, and together the mass and the projectile were supercritical. 0:09:17.200 --> 0:09:22.040 This bomb was equivalent to about fifteen thousand tons of TNT. 0:09:22.360 --> 0:09:26.120 It killed an estimated one hundred and fifty thousand people 0:09:26.360 --> 0:09:29.800 and leveled much of the city. The Manhattan Project also 0:09:29.840 --> 0:09:33.600 produced three plutonium cores to be used in implosion style 0:09:33.640 --> 0:09:37.480 bombs during World War II. In this setup, the plutonium 0:09:37.520 --> 0:09:42.400 core is surrounded by conventional explosives. When those explosives detonate, 0:09:42.559 --> 0:09:45.640 they compress the core, causing it to go from subcritical 0:09:45.720 --> 0:09:49.760 to supercritical. One of these cores was detonated at a 0:09:49.800 --> 0:09:53.160 test at the Alamogordo Bombing and Gunnery Range also called 0:09:53.160 --> 0:09:57.840 the Trinity Site, on July sixteenth, nineteen forty five. Another 0:09:58.040 --> 0:10:00.240 was used in the bomb known as Fat Man, which 0:10:00.280 --> 0:10:04.480 was detonated over Nagasaki, Japan, on August ninth, nineteen forty five, 0:10:04.880 --> 0:10:09.360 killing an estimated seventy five thousand people. The third plutonium 0:10:09.440 --> 0:10:13.720 core was nearing completion when Japan announced its surrender on 0:10:13.760 --> 0:10:16.800 August fifteenth, nineteen forty five, meaning that it was no 0:10:16.880 --> 0:10:21.320 longer needed for World War two. Later, the US started 0:10:21.320 --> 0:10:25.600 planning Operation Crossroads, which was a test of nuclear weapons 0:10:25.640 --> 0:10:30.079 effects on warships at seed to take place off Bikini Atoll. 0:10:30.200 --> 0:10:32.360 This third core, the one. 0:10:32.160 --> 0:10:34.679 That would later be nicknamed the Demon Corps, was slated 0:10:34.720 --> 0:10:38.080 for use in these tests, but in the meantime it 0:10:38.080 --> 0:10:41.560 was used for criticality research. It was during that research 0:10:41.760 --> 0:10:44.840 that they nicknamed it the Demon cor even though to 0:10:44.880 --> 0:10:49.800 be clear, did not kill nearly as many people as 0:10:49.920 --> 0:10:53.760 the other two that were detonated over cities. And we're 0:10:53.800 --> 0:10:55.800 going to talk more about the Demon Corps after we 0:10:55.880 --> 0:11:08.760 first pause for a sponsor break. The plutonium core that 0:11:08.880 --> 0:11:14.040 was eventually nicknamed the Demon Core was originally nicknamed Rufus. 0:11:14.440 --> 0:11:17.520 I don't know why, but so many sources have said 0:11:17.559 --> 0:11:22.840 that that seems legitimate. It was a six point two 0:11:23.040 --> 0:11:28.160 kilogram or thirteen point seven pound sphere really two hemispheres 0:11:28.600 --> 0:11:33.240 made of refined plutonium and gallium. Under normal conditions, it 0:11:33.280 --> 0:11:36.200 was ninety five percent of a critical mass, so it's 0:11:36.240 --> 0:11:39.559 often described as having a hair trigger, although it had 0:11:39.600 --> 0:11:42.319 been created for use in a bomb. This hair trigger 0:11:42.400 --> 0:11:47.199 also made the core useful for criticality experiments. Physicists could 0:11:47.320 --> 0:11:50.800 intentionally reflect neutrons back at the core to push it 0:11:50.920 --> 0:11:54.600 close to criticality and gather data about what was happening. 0:11:55.320 --> 0:11:58.920 Physicist Richard Feynman, who's work with the Manhattan Project included 0:11:58.920 --> 0:12:03.200 helping to work out stand to prevent criticality accidents, reportedly 0:12:03.320 --> 0:12:08.360 nicknamed these types of experiments tickling the Dragon's Tail. On 0:12:08.480 --> 0:12:12.200 August twenty first, nineteen forty five, twenty four year old 0:12:12.240 --> 0:12:16.440 graduate student Harry Dallion Junior was working by himself in 0:12:16.520 --> 0:12:18.880 the lab. Because of the nature of the work that 0:12:19.000 --> 0:12:21.360 was being done at Los Alamos, like it was critical 0:12:21.400 --> 0:12:23.840 to the war effort, it involved part of the nation's 0:12:23.880 --> 0:12:28.120 nuclear material stockpile, it was standard for security guards to 0:12:28.200 --> 0:12:31.640 always be present, so even though Dallian was working alone 0:12:31.640 --> 0:12:34.320 on this experiment, there was one other person in the 0:12:34.400 --> 0:12:37.920 room that was twenty nine year old Private Robert Hemerley, 0:12:38.000 --> 0:12:40.720 who was sitting at a table about twelve feet away 0:12:40.720 --> 0:12:44.640 from the core. Dallian was using tungsten carbid bricks to 0:12:44.679 --> 0:12:48.199 build a reflective wall around the plutonium core by hand. 0:12:49.040 --> 0:12:52.200 The bricks reflected neutrons back at the core, inching it 0:12:52.280 --> 0:12:55.880 closer to criticality. The more bricks he added, the more 0:12:55.920 --> 0:12:58.920 neutrons were reflected, and the closer the core got to 0:12:58.960 --> 0:13:02.600 going critical. As Dallian was about to add the last 0:13:02.720 --> 0:13:06.880 brick in this structure, his instruments showed that doing so 0:13:07.360 --> 0:13:09.760 was going to cause the core to go critical, so 0:13:10.320 --> 0:13:13.520 he tried to pull that last brick away, but as 0:13:13.559 --> 0:13:16.520 he did, it slipped out of his hand and dropped 0:13:16.679 --> 0:13:20.480 directly onto the core. Dallian used his other hand to 0:13:20.600 --> 0:13:23.120 knock the dropped brick away, but it was too late. 0:13:23.679 --> 0:13:25.959 There was a wave of heat and a brief flash 0:13:26.000 --> 0:13:28.720 of blue light all around the exterior of the sphere. 0:13:29.360 --> 0:13:32.440 That light was probably Chirinkov radiation, which is the result 0:13:32.440 --> 0:13:35.280 of charged particles moving faster than the speed of light 0:13:35.640 --> 0:13:40.520 through a transparent medium like air. In that brief moment 0:13:40.840 --> 0:13:43.800 between when he dropped the brick and when he knocked 0:13:43.800 --> 0:13:47.480 it away, Dallian was hit with a blast of neutron radiation. 0:13:48.200 --> 0:13:51.480 He disassembled the reflector that he had built, and that 0:13:51.679 --> 0:13:55.320 continued to expose him to gamma radiation while he was 0:13:55.360 --> 0:13:59.760 doing so. Today, absorbed radiation is measured in gray, with 0:14:00.000 --> 0:14:03.720 its one gray being equivalent to one hundred rads. A 0:14:03.760 --> 0:14:07.080 sudden whole body dose of zero point seven gray is 0:14:07.200 --> 0:14:11.679 enough to cause acute radiation sickness. Sometimes symptoms can develop 0:14:11.800 --> 0:14:15.800 at as little as zero point three gray. Dallian's dose 0:14:15.920 --> 0:14:20.000 was estimated at five point one gray. He died twenty 0:14:20.000 --> 0:14:23.880 five days after the accident on September fifteenth, nineteen forty five. 0:14:24.760 --> 0:14:28.480 Private Hammerley's dose was estimated at zero point five gray. 0:14:29.160 --> 0:14:33.360 He survived this incident apparently without serious injury at the time. 0:14:33.440 --> 0:14:36.880 If you read older articles that were published before his 0:14:37.080 --> 0:14:40.560 death later on like they'll say that he wasn't seriously harmed, 0:14:41.080 --> 0:14:43.640 but he wound up dying of leukemia, which might have 0:14:43.680 --> 0:14:48.440 been related to this radiation exposure, when he was sixty two. Afterward, 0:14:48.600 --> 0:14:53.239 criticality experiments continued at Los Alamos in spite of this fatality. 0:14:53.320 --> 0:14:57.080 Although some new safety standards were put into play, the 0:14:57.200 --> 0:15:00.120 list of people allowed to do these kinds of experiments 0:15:00.200 --> 0:15:03.640 was shortened, with two sets of monitoring equipment required for 0:15:03.720 --> 0:15:08.000 each experiment. The new standards reiterated that at least two 0:15:08.120 --> 0:15:11.120 people in addition to the guard, had to be present 0:15:11.160 --> 0:15:14.880 for this kind of work. Researchers also started discussing whether 0:15:14.920 --> 0:15:17.840 it would be better to do these kinds of experiments remotely, 0:15:18.240 --> 0:15:20.640 so that if a criticality did happen, it would be 0:15:20.680 --> 0:15:24.680 too far away from people to hurt them. Operation Crossroads 0:15:24.760 --> 0:15:27.640 was scheduled to start in July of nineteen forty six, 0:15:28.280 --> 0:15:31.040 but before the core was sent to the Marshall Islands 0:15:31.040 --> 0:15:34.960 to be used there, physicists were doing one last set 0:15:35.000 --> 0:15:38.920 of criticality experiments with it. On May twenty first, nineteen 0:15:39.000 --> 0:15:43.280 forty six, Canadian physicist Lewis Slowten was using a hollow 0:15:43.360 --> 0:15:47.240 beryllium sphere to mostly cover up the core and reflect 0:15:47.360 --> 0:15:51.680 neutrons back into it. The sphere had two halves, The 0:15:51.720 --> 0:15:54.480 core was sort of resting in the bottom half, and 0:15:54.520 --> 0:15:57.360 he had his thumb threaded through a hole in the 0:15:57.400 --> 0:16:00.200 top half so that he could adjust the positioning this 0:16:00.280 --> 0:16:03.640 sort of dome with his hand. He knew that if 0:16:03.640 --> 0:16:07.720 the sphere closed completely it could cause a criticality, so 0:16:07.760 --> 0:16:11.200 he used the end of a screwdriver to keep the 0:16:11.240 --> 0:16:13.200 two halves slightly separate. 0:16:13.680 --> 0:16:14.400 This sounds like the. 0:16:14.400 --> 0:16:16.240 Kind of thing I would do at my house with 0:16:16.280 --> 0:16:18.680 something that is not dangerous, And even so my husband 0:16:18.720 --> 0:16:20.360 would go, are you sure that's how you want to 0:16:20.400 --> 0:16:20.640 do it? 0:16:21.080 --> 0:16:21.320 Yes? 0:16:21.640 --> 0:16:26.160 Yes, I have a story on this subject about myself 0:16:26.280 --> 0:16:28.600 that I will probably tell in our Friday behind the 0:16:28.640 --> 0:16:31.080 scenes fabulous. 0:16:30.720 --> 0:16:32.120 While I have. 0:16:33.560 --> 0:16:36.000 Some understanding of how a person might do a really 0:16:36.040 --> 0:16:39.280 foolish thing, knowing how foolish it is, I was not 0:16:39.560 --> 0:16:47.400 handling potentially critical nuclear weapons cores at the time. As 0:16:47.480 --> 0:16:51.360 he was doing this, the screwdriver slipped and the dome 0:16:51.680 --> 0:16:55.000 totally closed. There was a brief flash of blue light 0:16:55.080 --> 0:16:57.800 that was visible over the normal illumination of the room. 0:16:58.360 --> 0:17:01.000 This lasted only a moment as and flipped the dome 0:17:01.120 --> 0:17:05.480 off of the core. Slowden seems to have immediately understood 0:17:05.520 --> 0:17:09.159 that he was not going to survive this accident, saying, well, 0:17:09.640 --> 0:17:14.280 that does it. In general, a whole body radiation dose 0:17:14.320 --> 0:17:18.080 of more than ten gray is inevitably fatal, and his 0:17:18.280 --> 0:17:22.560 has been estimated at twenty one gray. At the same time, 0:17:22.680 --> 0:17:25.200 he had the presence of mind to try to document 0:17:25.240 --> 0:17:28.400 where the other seven observers in the room had been 0:17:28.480 --> 0:17:31.000 standing at the time, and then to try to calculate 0:17:31.080 --> 0:17:34.520 how large of a dose of radiation each of them received. 0:17:35.280 --> 0:17:38.840 Their doses have been estimated as ranging between zero point 0:17:38.920 --> 0:17:43.160 three seven and three point six gray. Slowden also tried 0:17:43.160 --> 0:17:46.879 to detect how much radiation was present in other objects 0:17:46.920 --> 0:17:49.840 that were in the room, but the detectors themselves had 0:17:49.880 --> 0:17:53.320 been contaminated in the accident. At the same time, he 0:17:53.560 --> 0:17:57.520 wasn't thinking entirely clearly. He asked a colleague to scatter 0:17:57.640 --> 0:18:01.760 film badges used to detect radiation exposure around the area, 0:18:02.040 --> 0:18:04.359 and that required the colleague to get close to the 0:18:04.440 --> 0:18:08.680 radioactive corps to do so. Slotin died nine days after 0:18:08.720 --> 0:18:11.760 this accident at the age of thirty five, and although 0:18:11.760 --> 0:18:14.359 he was the only person killed, three other people in 0:18:14.400 --> 0:18:18.600 the room had to be hospitalized for acute radiation exposure. 0:18:18.440 --> 0:18:20.040 And one of them was Alvin C. 0:18:20.359 --> 0:18:23.639 Graves, who was the closest to Slowtin physically. When this 0:18:23.760 --> 0:18:28.520 accident happened, Slowtin had actually been training Graves as his replacement. 0:18:29.280 --> 0:18:32.080 Graves was seriously injured and for a time it was 0:18:32.160 --> 0:18:34.760 not certain whether he was going to survive. He later 0:18:34.840 --> 0:18:38.600 developed cataracts and thyroid issues, and his death from a 0:18:38.600 --> 0:18:41.840 heart attack nineteen years later may also have been related. 0:18:42.400 --> 0:18:46.520 In general, people have viewed Harry Dallion Junior's accident with 0:18:46.560 --> 0:18:50.680 a bit more sympathy than Lewis Slotin's. Dallian was working alone, 0:18:50.680 --> 0:18:54.159 which was against protocol, but he was also a graduate student, 0:18:54.280 --> 0:18:58.440 so he was not as experienced as many of his colleagues. Slowtin, 0:18:58.520 --> 0:19:00.920 on the other hand, was not only as senior scientist, 0:19:01.080 --> 0:19:03.760 but had also co authored the official report on the 0:19:03.880 --> 0:19:07.960 accident that had killed Harry Dallion, so he definitely understood 0:19:08.000 --> 0:19:11.879 the risks and the potential for accident. His experiment was 0:19:11.960 --> 0:19:14.959 meant to be done with two one inch spacers between 0:19:15.000 --> 0:19:18.400 the two halves of the beryllium sphere, but Slotin had 0:19:18.440 --> 0:19:21.639 removed these and was using the screwdriver in their place. 0:19:22.640 --> 0:19:26.280 Multiple other scientists who were aware of the criticality experiment 0:19:26.359 --> 0:19:29.840 he was doing thought it was inordinately dangerous, and in 0:19:29.920 --> 0:19:32.960 general he had a reputation for being a little too 0:19:33.040 --> 0:19:38.119 cavalier around things like atomic bomb cores. Scientists nicknamed this 0:19:38.240 --> 0:19:41.199 corps the demon Corps, not just because it had been 0:19:41.280 --> 0:19:44.439 part of both of these fatal accidents, but also because 0:19:44.480 --> 0:19:48.480 of some eerie similarities between them. Both accidents took place 0:19:48.560 --> 0:19:50.919 on the twenty first of the month and on a Tuesday, 0:19:51.440 --> 0:19:54.280 and Slotin and Dallion both died in the same hospital 0:19:54.359 --> 0:19:58.040 room at the US Engineer's Hospital at Los Alamos. By 0:19:58.040 --> 0:20:02.720 this point, work had started on remote facility for criticality experiments, 0:20:02.760 --> 0:20:06.159 and after the second accident with the demon Core, hands 0:20:06.160 --> 0:20:10.720 on criticality experiments like this were banned. In nineteen forty seven, 0:20:10.840 --> 0:20:15.560 criticality experiments resumed at the newly completed critical Experiments facility 0:20:15.640 --> 0:20:19.680 at what was known as the Paharito Site. Criticality experiments 0:20:19.720 --> 0:20:22.600 there were handled with machinery and took place a quarter 0:20:22.680 --> 0:20:25.040 mile from the control room where the people doing the 0:20:25.080 --> 0:20:29.439 experiments were. Since the amount of radiation drops dramatically the 0:20:29.560 --> 0:20:32.280 farther you are away from the source, this was much 0:20:32.320 --> 0:20:36.399 safer than doing something like stacking reflective blocks with your hands. 0:20:36.840 --> 0:20:39.840 Dallian and Slotan were the only two people to die 0:20:39.920 --> 0:20:45.080 from acute radiation exposure at Los Alamos during the Manhattan Project. 0:20:45.400 --> 0:20:48.359 Although there were numerous other deaths in and around the 0:20:48.400 --> 0:20:51.480 facility during those same years, a lot of them were 0:20:51.480 --> 0:20:55.240 from accidents that had nothing to do with radioactive materials 0:20:55.320 --> 0:21:00.040 or bombs. This included motor vehicle accidents, construction accidents, and 0:21:00.119 --> 0:21:03.040 in one case, a ten year old who drowned when 0:21:03.040 --> 0:21:07.720 a canoe capsized. In nineteen forty six, three custodians also 0:21:07.880 --> 0:21:11.439 died of ethylene glycol poisoning after drinking wine that was 0:21:11.480 --> 0:21:14.960 mixed with antifreeze. In terms of the demon Core, for 0:21:15.200 --> 0:21:17.760 years after this incident happened, it was believed that it 0:21:17.800 --> 0:21:20.560 was sent on to Bikini Atoll for use in Operation 0:21:20.680 --> 0:21:24.720 Crossroads as planned, and while it was described as quote 0:21:24.760 --> 0:21:27.520 a little hot but not too hot to handle, after 0:21:27.560 --> 0:21:30.960 that second accident, it was saved for the last detonation, 0:21:31.359 --> 0:21:34.080 just in case that was going to affect the results. 0:21:34.560 --> 0:21:37.480 That last test wound up being canceled, and the demon 0:21:37.560 --> 0:21:41.040 Cor was later melted down and reintegrated into the nuclear 0:21:41.080 --> 0:21:45.320 material stockpile. At some point it was probably incorporated into 0:21:45.400 --> 0:21:48.879 other weapons. Before we move on, we should note that 0:21:48.880 --> 0:21:52.880 there have been ongoing issues with safety at Los Alamos 0:21:53.000 --> 0:21:56.840 National Laboratory in more recent years. Aside from that twenty 0:21:56.840 --> 0:22:01.560 eleven plutonium photo op that we mentioned earlier. In twenty seventeen, 0:22:01.640 --> 0:22:05.360 it was rated does not meet expectations in the Department 0:22:05.359 --> 0:22:10.159 of Energy Nuclear Criticality Safety Programs annual report that was 0:22:10.240 --> 0:22:14.360 raised up to adequate but needs improvement in twenty eighteen 0:22:14.440 --> 0:22:18.280 and twenty nineteen. Also, that second accident with the demon 0:22:18.359 --> 0:22:21.639 core is dramatized in the nineteen eighty nine film Fat 0:22:21.680 --> 0:22:24.960 Man and Little Boy, with John Cusack as a fictionalized 0:22:25.000 --> 0:22:28.480 SLOTIN who is named Michael Merriman in the film. Yeah, 0:22:28.480 --> 0:22:31.199 I watched just that scene while I was working on this, 0:22:31.280 --> 0:22:34.000 and even knowing literally what's going to happen, I found 0:22:34.040 --> 0:22:40.159 it very tense. Yeah, so we're gonna take a quick break. 0:22:48.600 --> 0:22:51.800 The two incidents that we already talked about happened during 0:22:52.000 --> 0:22:56.720 criticality experiments. The researchers were intentionally pushing the limits to 0:22:56.800 --> 0:23:00.240 do tests and gather data. But many of the other 0:23:00.400 --> 0:23:05.040 nuclear criticality accidents have happened while nuclear material was being 0:23:05.200 --> 0:23:09.240 processed in some way. So these are people working at 0:23:09.280 --> 0:23:14.240 facilities that were actively trying to avoid a criticality. However, 0:23:14.280 --> 0:23:16.560 in a lot of cases, the workers who were actually 0:23:16.600 --> 0:23:21.480 handling this material also were not nuclear physicists. In some cases, 0:23:21.520 --> 0:23:24.920 they hadn't really been trained in criticality safety at all. 0:23:25.040 --> 0:23:28.320 They didn't necessarily know that something like the size and 0:23:28.440 --> 0:23:31.879 shape of a container could be an integral part of 0:23:31.920 --> 0:23:36.920 preventing a disaster. For example, on March fifteenth, nineteen fifty three, 0:23:37.080 --> 0:23:41.040 at the Mayak Enterprise facility in Russia, two workers were 0:23:41.040 --> 0:23:45.879 transferring plutonium solution from one vessel to another. Vessels had 0:23:45.920 --> 0:23:48.679 been arranged in a row along a wall, and every 0:23:48.720 --> 0:23:52.480 other vessel was supposed to be left empty to prevent criticality. 0:23:53.440 --> 0:23:56.359 The vessels were also supposed to contain at most five 0:23:56.480 --> 0:24:00.359 hundred grams of plutonium, but neither of those limits was 0:24:00.400 --> 0:24:04.600 actually being followed. Vessels contained plutonium when they weren't supposed to, 0:24:05.200 --> 0:24:08.320 and also contained more than that five hundred grand limit, 0:24:08.840 --> 0:24:13.160 So when a criticality occurred during this plutonium transfer, workers 0:24:13.320 --> 0:24:16.639 not only did not know that it had happened, but 0:24:16.720 --> 0:24:18.840 they also did not know that it had caused a 0:24:18.920 --> 0:24:22.080 serious problem because they had not been trained on this. 0:24:22.640 --> 0:24:25.800 They just noticed that one of the vessels became warm 0:24:25.920 --> 0:24:29.360 to the touch, so they started removing the plutonium solution 0:24:29.600 --> 0:24:33.040 out of it and kept on working. They only reported 0:24:33.080 --> 0:24:35.840 the incident two days later when one of them suddenly 0:24:35.880 --> 0:24:39.040 became ill. The worker who was closer to the vessel 0:24:39.080 --> 0:24:41.520 when it went critical ultimately had to have both of 0:24:41.560 --> 0:24:45.480 his legs amputated because of extreme tissue damage from this exposure. 0:24:46.000 --> 0:24:46.520 But in some. 0:24:46.640 --> 0:24:50.720 Cases, the staff involved in these incidents were trained. That 0:24:50.880 --> 0:24:53.399 was the case with Cecil Kelly, who received a lethal 0:24:53.480 --> 0:24:56.800 radiation dose in a criticality accident at Los Alamos on 0:24:56.840 --> 0:25:00.560