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KF5JRV > TODAY 26.04.19 12:31l 66 Lines 3631 Bytes #999 (0) @ WW
BID : 35245_KF5JRV
Read: GUEST
Subj: Today in History - Apr 26
Path: IW8PGT<IR2UBX<F1OYP<ON0AR<GB7CIP<AB0AF<KF5JRV
Sent: 190426/1130Z 35245@KF5JRV.#NWAR.AR.USA.NA BPQ6.0.18
On April 26, 1986, the world’s worst nuclear power plant accident occurs
at the Chernobyl nuclear power station in the Soviet Union. Thirty-two
people died and dozens more suffered radiation burns in the opening days
of the crisis, but only after Swedish authorities reported the fallout
did Soviet authorities reluctantly admit that an accident had occurred.
The Chernobyl station was situated at the settlement of Pripyat, about
65 miles north of Kiev in the Ukraine. Built in the late 1970s on the
banks of the Pripyat River, Chernobyl had four reactors, each capable of
producing 1,000 megawatts of electric power. On the evening of April 25,
1986, a group of engineers began an electrical-engineering experiment on
the Number 4 reactor. The engineers, who had little knowledge of reactor
physics, wanted to see if the reactor’s turbine could run emergency
water pumps on inertial power.
As part of their poorly designed experiment, the engineers disconnected
the reactor’s emergency safety systems and its power-regulating system.
Next, they compounded this recklessness with a series of mistakes: They
ran the reactor at a power level so low that the reaction became
unstable, and then removed too many of the reactor’s control rods in an
attempt to power it up again. The reactor’s output rose to more than 200
megawatts but was proving increasingly difficult to control.
Nevertheless, at 1:23 a.m. on April 26, the engineers continued with
their experiment and shut down the turbine engine to see if its inertial
spinning would power the reactor’s water pumps. In fact, it did not
adequately power the water pumps, and without cooling water the power
level in the reactor surged.
To prevent meltdown, the operators reinserted all the 200-some control
rods into the reactor at once. The control rods were meant to reduce the
reaction but had a design flaw: graphite tips. So, before the control
rod’s five meters of absorbent material could penetrate the core, 200
graphite tips simultaneously entered, thus facilitating the reaction and
causing an explosion that blew off the heavy steel and concrete lid of
the reactor. It was not a nuclear explosion, as nuclear power plants are
incapable of producing such a reaction, but was chemical, driven by the
ignition of gases and steam that were generated by the runaway reaction.
In the explosion and ensuing fire, more than 50 tons of radioactive
material were released into the atmosphere, where it was carried by air
currents.
On April 27, Soviet authorities began an evacuation of the 30,000
inhabitants of Pripyat. A cover-up was attempted, but on April 28
Swedish radiation monitoring stations, more than 800 miles to the
northwest of Chernobyl, reported radiation levels 40 percent higher than
normal. Later that day, the Soviet news agency acknowledged that a major
nuclear accident had occurred at Chernobyl.
In the opening days of the crisis, 32 people died at Chernobyl and
dozens more suffered radiation burns. The radiation that escaped into
the atmosphere, which was several times that produced by the atomic
bombs dropped on Hiroshima and Nagasaki, was spread by the wind over
Northern and Eastern Europe, contaminating millions of acres of forest
and farmland. An estimated 5,000 Soviet citizens eventually died from
cancer and other radiation-induced illnesses caused by their exposure to
the Chernobyl radiation, and millions more had their health adversely
affected. In 2000, the last working reactors at Chernobyl were shut down
and the plant was officially closed.
73 de Scott KF5JRV
Pmail: KF5JRV@KF5JRV.#NWAR.AR.USA.NA
email: KF5JRV@GMAIL.COM
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