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www.us- tech.com


Tech-Op-ed July, 2019 SOUNDING OFF


By Michael Skinner Editor


A Hot Mess O


n April 26th, 1986, the fourth reactor at the Chernobyl Power Plant in Northern Ukrainian SSR experienced an uncontrolled nuclear chain re- action that is still widely considered to be the worst nuclear power


plant disaster to date. It was known since at least 1982 that the reactor’s wa- ter cooling circulation system was a potential issue. In the event of a power outage, it was critical that water keep circulating in the reactor for about a minute until emergency generators could kick on. After a series of three tests, a solution still had not been found. On the fourth such test — a simulated power outage — a failed test pro-


cedure, a 10-hour delay and lack of the original shift that had prepared the test, combined with the disabling of many necessary safety systems, allowed the reactor core to overheat uncontrollably and explode. This steam explosion spewed radioactive material into the air, and the resulting open-air fire con- tinued to release contamination for about nine days. Approximately 400 times more radioactive material was released from


Chernobyl than by the atomic bombing of Hiroshima and Nagasaki. Belarus, Ukraine and Russia were the hardest hit, with roughly 40,000 square miles of land across the three nations significantly contaminated by iodine-131, cae- sium-134, caesium-137, and strontium-90 fallout. At the plant itself, the most damaged parts of the building are estimat-


ed to have emitted around 5.6 roentgens per second, adding up to more than 200,000 per hour. A lethal dose to a human is around 500 roentgens over five hours. The majority of the reactor crew, including chief Alexander Akimov had defective dosimeters and continued working, trying to pump water into the reactor in ignorance. Most were dead within weeks. The cleanup operation lasted months, with most of the deadly debris col-


lected inside what was left of the reactor. However, the most heroic efforts were undertaken by the thousands of “liquidators” whose job it was to shovel around 100 tons of highly radioactive material off the roof of reactor four. This was necessary for the “sarcophagus” to be built, a concrete tomb that would cover the reactor and limit the amount of radioactive dust still being released. These men, nicknamed “bio-robots” because of their unwieldy protective


gear, worked in shifts that were a maximum of a minute and a half long to clear around 90 percent of the debris. While each man was only supposed to perform his shift a single time, many reported having to take multiple trips around the roof, absorbing what would become fatal amounts of radiation. The other 10 percent of the roof debris was moved by poorly designed robots whose electronics were fried by the intense radiation, doomed to become obstacles themselves. The construction of the sarcophagus was another seemingly impossible


task. Crane operators were directed blindly from lead-lined cabins by radio, moving huge pieces of concrete. With a lifespan of only 30 years, the concrete was on the verge of collapse when work began on a new confinement struc- ture.


Built in a joint venture by French contractors Vinci Construction Grands


Projets and Bouygues Construction, and completed in 2017, the massive “Chernobyl New Safe Confinement” came with a price tag of about $2.3 bil- lion. The confinement was assembled on rails west of the reactor and pushed along PTFE pads with hydraulics, guided by lasers. A difficult process, the structure began its 1,000-foot journey on November 14, 2016, and was finally in place on November 29. A monument to the builders of the original sarcophagus can be found in


front of the finished confinement. The disaster itself and the saga that result- ed from the cleanup efforts strongly affected the response to the 2011 Fukushima Daiichi power plant meltdown in Japan, with many calling for less human presence and more actual robots — the spiritual successors to the thousands of Soviet “bio-robots” who risked their lives for shovelfuls of ra- dioactive graphite. Still, as with Chernobyl, many of the robots used at Fukushima Daiichi


also failed in the presence of radiation, turning the plant into gravesite for cleanup bots. There are new projects, such as one collaboration between sev- eral British Universities, that hopes to equip these cleanup bots with AI, mak- ing them intelligent enough to avoid obstacles or stop when the area gets too unsafe. Hopefully, the robots will never have to be used. r


PUBLISHER’S NOTE


By Jacob Fattal Publisher


A Giant Leap: Apollo 11 Turns 50


T


his month, the Apollo 11 Moon landing mission turns 50 years old. On July 16, 1969, a Saturn V rocket launched from Kennedy Space Center carrying commander Neil Armstrong, Buzz Aldrin, who piloted the lu-


nar landing module Eagle, and Mike Collins who piloted the command mod- ule Columbia. Anyone alive at the time will remember where they were on July 20,


when Armstrong took his famous “one small step.” He then spent about 20 minutes alone on the surface of the Moon before being joined by Aldrin. I re- member boarding a bus at 17 years old and listening as the driver explained what was happening as news came through the radio. Once the Eagle landed, everyone on the bus erupted in cheers and applause. Armstrong’s first step and his return from the surface with Aldrin to


dock the landing module with Columbia in orbit and their successful return journey seems miraculous, even today. It also marked the culmination of a goal established by President John F. Kennedy in 1961 of “before this decade is out, landing a man on the Moon and returning him safely to Earth.” After Apollo 11, there were five subsequent missions that landed astronauts on the Moon. The final one, Apollo 17, landed in December 1972. Since then, plans to return humans to the Moon or to other planets has


fallen by the wayside. At least until recent years, when private companies such as SpaceX have been conducting their own launches. In the case of SpaceX, the company plans to use its latest and largest rocket, the BFR, to es- tablish a human base on Mars in the next decade. First, the company plans to send robotic cargo flights to prepare the base site and deliver equipment, ve- hicles, solar panels, and infrastructure to support humans. Two more robotic flights will follow and finally two manned flights carrying humans, by 2025. These last few years have seen an exciting resurgence of interest and in-


vestment in space travel, spearheaded by private companies. Blue Origin, Vir- gin Galactic, SpaceX, Bigelow Aerospace, and many others are now competing for, well, space in the marketplace. Their goals are varied. SpaceX is focused on putting humans on Mars, while Blue Origin offers paid spaceflights to civil- ians, as well as payload services in orbit. Some companies, such as Northrop Grumman, launch satellites as a service, for which there is rapidly growing demand as we look forward to more broad, global wireless communications. The collaborative nature of the birth of manned spaceflight has affected


the way private companies have approached it. NASA has estimated that it took nearly 400,000 people to accomplish the Moon landings. While the efforts of thousands were needed to send Armstrong, Collins and Aldrin to the Moon and back, it is surely a small price to pay for the millions more the Apollo 11 mis- sion inspired and its effect on each gener- ation to come. r


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