If we take a
closer look at the history of nuclear reactor accidents, all of them have one
thing in common. They all have been a loss-of-coolant accident. Everything that
follows is a simple one-two-three scenario. Count to one.
Overheated
uranium fuel rods start to melt. Nuclear reactor vessel integrity is
compromised. Count to two. Outside air is introduced into a reactor, then an
explosion. Count to three. Radioactive materials are released into the
environment. The same very basic scenario should be expected in future
accidents.Chances are that the next loss-of-coolant accident will take place at
the nuclear reactor in Bushehr, Iran. It has had more than enough warnings,
reports, and speculations related to Stuxnet penetration into computers on
Bushehr nuclear power station. Only, contrary to
all those expectations, the future accident would not have anything to do with
Stuxnet controlled computers. But first let's have a brief overview of the past
accidents.On March 28, 1979 a series of mechanical failures combined with the
plant operator's mistakes led to the loss of a large amount of coolant in the
Unit 2 nuclear reactor at the Three Mile Island Nuclear Generating Station near
Harrisburg, Pennsylvania. Until the coolant supply was restored, the nuclear
fuel was already partially melted. It was followed by the hydrogen explosion in
the reactor's containment building. Radioactive gases were released into the
atmosphere. A small amount of coolant contaminated with radioactive particles
found its way out of the reactor's containment building. Fortunately there was
no loss of human lives and no significant radioactive contamination to the
environment.On April 26, 1986 the fourth reactor at the Chernobyl Nuclear Power
Plant, Ukraine, exploded after it lost coolant as the result of an unsuccessful
experiment. Two plant operators lost their lives as result of the explosion.
Air entered the reactor core and started a fire with the overheated neutron
moderator blocks made from graphite. The explosion and fire led to the
scattering of large amounts of radioactive materials 60,000 square miles in
Belarus, Russia and Ukraine. Additional radioactive fallout reached over much
of the northern hemisphere.Twenty eight firemen, who were the first responders,
died within three months from Acute Radiation Sickness. Exposure to high doses
of radiation forever changed the lives of 600,000 people, a.k.a.
"liquidators of Chernobyl accident", who were involved in fire
fighting, decontamination, and clean-up operations. Over eight million
Belarusians, Ukrainians, and Russians were exposed to the radiation.
Approximately four thousands people, who were children during the accident,
were later diagnosed with thyroid cancer.On March 11, 2011 an earthquake of the
magnitude 9.0, resulting in a tsunami with waves in excess of 30 feet in
height, devastated a large part of North East Japan. The Fukushima Daiichi
Nuclear Power Station was left without power and the tsunami destroyed
emergency power generators. Coolant pumps stopped working. The fuel rods began
to melt. Inability to supply enough quantities of sea water to cool down fuel
rods led to a series of hydrogen explosions, damage to reactor containment
structures and buildings, and the release of radioactive gases and contaminated
water into the environment. The evacuation of people from the area close to the
nuclear plant already took place. The plant personnel continue their efforts to
prevent nuclear disaster.On February 28, 2011 the Rosatom (Russia's nuclear
energy agency) announced that nuclear fuel will be unloaded from the Bushehr
nuclear plant in Iran because of concerns that metal particles might be
contaminating fuel assemblies. The reason for contamination was a worn-out node
inside one of the four cooling pumps. According to independent experts, it
wouldn't be a loss-of-coolant accident this time. Their prediction was that
metal particles could damage the fuel rods and lead to the release of
radioactive gases from the fuel into the coolant, and then into the
environment. The Bushehr reactor's coolant related threat was discovered prior
to start-up. But keep in mind that all pumps servicing the reactor were built
forty years ago. The reactor was expected to start producing electricity as
early as in December 2010. So Iran is in a big rush to improve its prestige by
pushing the nuclear reactor to work. What does it mean for the rest of the
world? It means the Iranian nuclear reactor well could be the next in the getting
longer list of loss-of-coolant nuclear reactor accidents.
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