Because of the inaccurate low readings, the reactor crew chief Alexander Akimov assumed that the reactor was intact. The evidence of pieces of graphite and reactor fuel lying around the building where ignored, and the readings of another dosimeter brought in at 04:30am were dismissed under the assumption that the new dosimeter must have been defective. Akimov stayed with his crew in the reactor building until morning, sending members of his crew to try to pump water into the reactor. None of them wore any protective gear. Most, including Akimov, died from radiation exposure within three weeks.
Under extremely hazardous conditions, thousands of "Liquidators" worked to contain the remains of the fourth reactor. The shelter surrounding the reactor was completed less than six months after the explosion during peak radioactivity levels. The massive concrete and steel "Sarcophagus", quickly constructed using "arms length" methods, has deteriorated over the years, creating a potentially hazardous situation. Several repairs were made to the current shelter, including the stabilisation of the ventilation stack and reinforcement of the roof. In addition, a plan for the construction of a more secure and permanent structure to be built around the existing Sarcophagus was drafted; work has already begun on the infrastructure of this new shelter. The plan, called the Shelter Implementation Plan, is a project of the Chernobyl Shelter Fund. Both efforts, whose combined expected expenditures over the next eight or nine years exceed $765 million, are administered by the European Bank for Reconstruction and Development.
You Didn’t See Graphite Around This Geiger Counter
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My professor at the University remembered well when the gamma counter in the labs suddenly went off scale around noon on April 30th. This was at the U of Zurich, Switzerland. As soon as you opened the windows, off they went. An event scary enough to never forget.
On the way out, people need to check to make sure they didn't pick up any radioactive contamination. This Geiger counter is used to check hands, and there's another device for checking the soles of shoes. The board behind it was rescued from the trash and put in place for security. It's a board with switches for employees' names, which serves as a reliable way to know who is in the reactor at all times.
I found in his laboratory also Leona Woods Marshall-- Fermiand Leona had just done some work on electron-neutron interaction; and Jack Steinberger who was working away in the corner there with Geiger tubes and piles of graphite and lead doing something with cosmic rays. Fermi and Marshall were doing an experiment themselves using Geiger tubes on positronium; they had built the tubes themselves incorporating a cotton thread soaked with sodium-22 radioactive material, which would give a positron which would then annihilate and they were studying this. But Martin Deutch at MIT was studying too and he, pretty soon, scooped them because he had access to scintillation counters with end- window phototubes from RCA. Eventually Fermi got such phototubes, and we decided we would put them to work.
Part of my own work that summer of 1950 was beginning an experiment to measure the deuterium-deuterium deuterium-tritium cross-sections which hadn't been measured for ten years previously at the University of Texas. And I thought it was a pretty weak read to lean on in deciding to build hydrogen bombs or not, when you didn't know what the cross-sections were. So I devised an experiment and began to build it there. When I had to leave at the end of the summer to come back to my responsibilities at Chicago, Fermi encouraged Jerry Kellogg and the laboratory director, Norris Bradbury, to import Jim Tuck from England-- he had been at Los Alamos during the war-- to continue this experiment, which was then published in 1954.
In 1951 I was back for the summer. I didn't share an office with Fermi. The Physics Division decided I would be better off as a consultant to the Theoretical Division and that's where I was ever after in my summers at Los Alamos. Fermmi was concerned that summer with a large number of things, including Taylor instability. If you have a stable interface like this water, you know, you perturb it and it ripples, and whatnot, and everybody knows that there are waves that run on the surface of the water. Everybody knows also to put a card over a full glass of water and you turn it over (I'm not going to do this for respect for the Ida Noyes Hall and the Max Palevsky Cinema) and the water stays in the glass-- it is stable. But it's meta-stable. If you take the card off, the interface is still supported by the air pressure but the water pretty soon falls out. This is a very important phenomenon in nuclear weaponry and had been plaguing the people at Los Alamos ever since they considered implosion weapons in 1944. Actually they were considered in 1942 but they really had to make them in order to use plutonium in 1944.
So Fermi had schematized the problem on his blackboard. Everybody knows that in the beginning stages of Taylor instability you assume a ripple on the surface, and instead of behaving sinusoidally in time it behaves exponentially in time with the same time behavior except it's imaginary instead of real or vice versa. So there is a time in which the amplitude doubles; the next interval it quadruples; the next interval it gets to be eight times as big. And pretty soon, of course, this cannot go on because the energy in the instability exceeds the energy that was driving it; the velocity exceeds the velocity of light. And so the question is what happens at large amplitudes? So Fermi said, let me make a model; I'll have a broad tongue which moves into the dense material; I'll have a narrow tongue that moves away from it and I'll just solve this numerically. So he did some of that but he wasn't quite satisfied with the solution. One afternoon around 4:50 p.m. John von Neumann came by and saw what Fermi had on the blackboard and asked what he was doing. So Enrico told him and John von Neumann said "That's very interesting." He came back about 15 minutes later and gave him the answer. Fermi leaned against his doorpost and told me, "You know that man makes me feel I know no mathematics at all."
In a panic the operators began inserting all the control rods. The graphite at the end of the rods and the water they displaced speed up the reaction. Within four seconds the power surges to 100 times the reactor's capacity. The uranium fuel disintegrated, burnt through its covers, and came into contact with the cooling water. At around the same time operators pressed emergency buttons.
A professor on board one of the helicopters told the BBC, "I think that was my trip to hell. There was this dark haze around the reactor, and we were in a helicopter...at a height of 300 meters, trying to find some way through for the trucks with liquid nitrogen. We were not there for long, but obviously there was no protection in the helicopter." The professor survived, The pilot and navigator later died from radiation-related illnesses.
The 1,000-square kilometer evacuated area is teaming with wildlife. Polesskiy National Park, within 20 miles of Chernobyl, has been described as the world's first radioactive nature reserve. Abandoned by humans, it is now the home of more elk (moose), deer, wild boar, lynx, reindeer, fox and wolves than lived there before the disaster...and these animals are doing well. An amazing 270 species of birds have been sighted in the area and 180 of them nest there. The lakes and rivers are full of fish and 40 rare plants have been identified. There area itself is lush and green, only geiger counter readings give a clue as to what happened.
The Ukrainian government said it didn't have the money to do the job itself and insisted that the foreign aid-donating countries would have to foot the bill. If the didn't the Ukrainian government threatened to keep operating the remaining Chernobyl reactors until they did. As of the mid 1990s the Ukrainian government had only given out around $100 million helping Chernobyl victims. [Source: Mike Edwards, National Geographic August 1994, May 1987]
In recent years, many laboratories started burning the cleaned sample in an elemental analyzer, which is coupled to the graphitization system. The sample is gassified under high heat in the elemental analyzer. In this way the lab can gain other information about the molecular composition of the sample from the analyzer. The CO2 is then turned into graphite by reacting with hydrogen at high temperature in the presence of iron powder, which acts as a catalyst. 2ff7e9595c
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