 This video is proudly sponsored by NordVPN, what about that later on? In the same year that a reactor in the UK set a light, another fire in the nuclear industry took place in the Rocky Flats plant in the US. The event would go on to be relatively unknown until another fire at the same site was discovered 10 years later. September 11th is a date that has become part of world history. However, today's subject isn't the 9-11 that normally springs to mind. Instead, a fire in a glove box in a plutonium process building will be the focus for this video. I'm going to rate today's subject matter here on the Plainly Difficult Disaster Scale. Located in Golden, Colorado, around here on a map, the Rocky Flats plant is situated on 384 acres inside a 6,550-acre nature reserve. Ground was broken in 1951 for a new site to build vital parts for the budding nuclear weapons industry in the United States. The construction work in a Pittsburgh Press article was estimated to cost around $45 million. The AEC appointed Dow Chemical Company as the plant's operator between 1952 and 1975. The main goal of the site was to produce plutonium pits, which form parts of the trigger to an atomic bomb. A pit is a hollow plutonium sphere that is imploded, creating an explosion that triggers the rest of the weapon. The demon core was a plutonium pit, however it wasn't hollow, but instead had two spheres with a ring in the middle. The site produced its first pit in 1953 and over the remainder of the 1950s would grow to 27 buildings. The facility manufactured most of the triggers for the US atomic weapon stockpile. That was until 1993 when production was abruptly ended. The pits were formed from plutonium buttons which looks pretty much how it sounds as seen here. From buttons the plutonium is formed into the hollow sphere needed for weapons production via foundry and machinery work. Although a vital part in the weapons production process, Rocky Flats was only a link in the manufacturing chain. As once the pits were created they were sent off to the Pantex facility near Amarillo, Texas. Not only did the facility deal with plutonium, but also uranium and beryllium, as well as a myriad of chemicals, including carbon tetrachloride, used as a cleaning solvent in the manufacturing process. The production buildings did not have fire suppression systems due to the risk of criticality incidents caused by water forming a moderator. But instead the buildings were fitted out with little combustible material as possible, and this seemed to work in a 1955 chemical explosion which was effectively dealt with. This brings us on to September 11th 1957 and building 71 which was used in the process for pit creation. As a side note building 71 was the first production building at the site. Room 180 contained glove boxes used to protect operators from the radioactive isotopes. Some at Rocky Flats were up to 20 metres in length with multiple lead lined gloves used to manipulate the tools needed for machining and forging. The boxes were made of stainless steel, had reinforced plexiglass windows and had Benalex shielding made of wood fibre and plastic to protect operators from neutron radiation. Extraction fans were provided to vent air from the glove boxes to prevent any release of radioactive dust. Multiple filters are provided en route for any material before it goes to building 71's vent stack. The ventilation system was equipped with heat sensors which were intended to switch off the fans preventing the spread of a fire, which is great, however this had been disabled due to false trips slowing down production. Plutonium can be a fire hazard if handled incorrectly but not stored in a dry environment. If in too high of a humidity room the plutonium can form hydrides on its surface, which are pyrophuric and may ignite in air at room temperature. This risk increases when the material is finely divided for instance in dust. Such a spontaneous combustion can be a deadly event with the potential to release radioactive particles. At 10pm this such incident began as a small amount of plutonium turning spontaneously combusted spreading the fire along the plexiglass. Ten minutes later the fire was discovered, the cooling fans were powered up to protect the firefighters from contamination as they attempted to use carbon dioxide to quell the flames. However this spread the hot plutonium dust into the filtration system, something that the heat sensors should have prevented however this was disabled. Plutonium burns in a similar fashion to charcoal, however the smouldering was a perfect ignition source for the highly flammable plastic within the glove boxes. After this failed and faced with an ever building up fire, the firefighters used something that they really shouldn't have been using when dealing with plutonium and that was water at 10.38pm. Right it's time to talk about this video sponsor NordVPN. Now if you look up various disasters and atomic incidents like me, then a little bit of anonymity is pretty handy. Needless to say that if I didn't have NordVPN and I know data logging I might be on some kind of disaster warning watch list. I've used several VPNs over the past couple of years and have enjoyed the protection I afford and I think NordVPN has the best user interface making it really easy to jump from one server to another. You can also bypass region locking for movie streaming sites which is an annoying part of living in the UK as you miss out on so many great shows. It has really been a lifesaver during lockdown while I've watched more than my weight of true crime documentaries. Also with NordVPN you can gain access to the EU only sites such as databases and archives which thanks to the GDPR rules aren't available in Northern America. For me it's really good as using NordVPN has allowed me to research on US only sites vital for some of the subjects I work on. NordVPN works on Windows, Mac OS, Linux, iOS and Android. If you're interested check out NordVPN by going to www.nordvpn.com slash playdifficult and use coupon code playingdifficult at checkout to get 70% off a two-year deal plus an additional one month with a huge discount. Thank you for listening to the advert. Although it initially stopped the flames which were from the burning plastic and other flammable materials inside the boxes the moisture reached the plutonium increasing its heat. There was also a massive risk to achieving a criticality accident as the water would help sustain the chain reaction. The air filtration system itself posed risk as the heat and moisture spread upwards by the fans. Ever since building 71 was first pressed into service the filters had not been replaced and were filled with plutonium dust which was much more susceptible to moisture. A minute after water was introduced a loud blast was experienced. The force bent a plenium steel frame in doing so spreading the fire into the filtration system. The explosion also destroyed the cap at the top of building 71's smokestack. On order of the health physicist's supervisor everyone evacuated building to escape the plutonium contamination which by now had spread throughout building 71. At 10.45pm fire was now discovered in the vital filter banks on the second floor the only thing preventing widespread contamination of radioactive particles released from the fire. As the fire burned contamination spread out from the damaged smokestack engulfing the surrounding area. At 2am the fire was declared knocked down however it wouldn't be completely stopped until 11.28am on the 12th of September. It was estimated that around 63kg of plutonium was present in room 180 at the time of the fire with 13-21kg being involved directly. It was estimated that around 500g of plutonium 239 and 240 was released into the atmosphere. However due to lack of proper monitoring and almost immediate cover up these figures are an educated guess at best. The contamination was spread by winds and some was deposited in the soil. The material is dangerous once ingested due to plutonium being an alpha particle emitter. The highest risk of exposure of the local population was the persons who were exercising or were working outside in areas where the plume of plutonium particles was near the ground. However some of the most at risk were the firefighters who for nearly 13 hours were exposed to the deadly plutonium. The highest dose was estimated to be 15mremes off site. The blaze heavily damaged building 71 necessitating the installation of an incinerator in 1958 to dispose of the amount of contaminated material. Elements such as strontium 90 and cesium 135 were detected as a result of the fire hinting at a criticality event. However officials denied that such event had occurred. The public wouldn't be aware of the incident for just over a decade until a second fire also involving plutonium was fought also using water. The only reports of the incidents in local newspapers claimed that none was injured and no release of radioactivity was recorded and the damage costs were estimated to be around $50,000. The cleanup of building 71 started as soon as the fire had ended. Work resumed on a limited scale before the end of 1957 but cleanup efforts would be continued all the way until early 1962. The building would be pushed back into service being renamed 771 with the whole site continuing to produce plutonium pits until 1993 when production was transferred to Oak Ridge National Laboratory. This was only after the site was raided by the EPA and FBI in 1989 after numerous reports of staff relating to deadly working conditions. Really the incident in 1957 is only scratching the surface of this radioactive dumpster fire of a place. Now don't worry I'll be doing another video soon about the 1969 fire and its wider impact on the site and also Rocky Flat's ultimate demise. A big thank you to NordVPN for the sponsorship. If you're interested check out NordVPN by going to www.nordvpn.com slash Plain Difficult and use coupon code Plain Difficult at checkout to get 70% off a two year deal plus an additional one month with a huge discount. Their support really helps out the channel. I hope you enjoyed the video. 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