There was no bottle! They built that plant without any containment
building...and paid the price. They also neglected to learn from a similar
accident that happened to a somewhat similar British plant (Windscale
They opted for a graphite system if I recall. There was an
interesting National Geographic about Chernobyl a few years back and
they showed, for example, the graveyard of helicopters and equipment
that had to be abandoned because it was too hot to be used again. In
the commentary they noted that people had been sneaking in and
stripping parts off to sell in the black market.
Notice that all the radiation readings in the article are in
micro-Roentgens, and the average for the area is now only
6 uR above global average background.
As a reality check, the LD50-30 dose is 500 Roentgens, or about
19,000,000 times higher. That's why the young lady doesn't fear
to tour through the area. As she says, people fear radiation all
out of proportion to the actual risks.
A good factual description of radiation effects and risks can be
Here's a snippet. (Note REM is Roentgen Equivalent Man and is
equivalent to whole body absorption of one Roentgen of gamma
radiation or ingestion of an alpha emitter with an output of 0.05
Roentgen. Alpha can't penetrate the skin, but it does more damage
if it gets inside the body than gamma or beta.)
4.1 Risk Comparison
Since many persons are particularly fearful of radiation, it may be helpful
to compare the risk from radiation exposure to some other risks encountered
in everyday life. Based on the straight-line model, a worker exposed to 1,000
millirem (one rem) per year for 30 years would lose about 30 days of life
expectancy due to increased risk of cancer. This is comparable to other
"safe" jobs. For comparison, the loss of life expectancy for some other risks
is given below.
Job or Other Risk Days of Life Expectancy Lost
Coal Mining 1100
Being 30% overweight 1300
Being President of the U.S. 1861
Being an average male smoker 2153
To put it another way, statistically the risk from one millirem of exposure
is approximately equal to the risk from taking one puff on a cigarette or
driving a car 0.15 miles on the highway. Many persons do not approach
radiation risk rationally. Some tend to ignore the risk because they cannot
see any immediate ill effects. Others have an irrational fear of radiation
entirely out of proportion to the actual risk (Radiophobia).
Note that the straight line model is considered overly conservative.
Areas with naturally high background levels do *not* have the number
of excess cancers predicted by the straight line model. This leads many
researchers to suggest that there is a threshold below which there is
no added risk due to radiation.
In fact, a number of such high background areas have a *reduced*
cancer risk compared to the general population. This leads some
researchers to conclude that small excess radiation exposures may
actually be helpful. As the quoted article says, the risk numbers are
so low, and confounding factors so many, that it is extremely difficult
to make a case either way for this hypothesis.
In any event, what all this means is that the "dead zone" around
Chernobyl is today primarily an irrational fear zone instead of an
area of actual credible threat.
Three major mistakes. 1) no containment structure, 2) a design with
a positive void coefficient, ie subject to thermal runaway, and 3) they
attempted to operate it completely against established procedures,
which in fact caused thermal runaway to occur.
US commercial reactors are designed with 1) effective containment
structures, 2) have negative void coefficient, ie damp down if they get
too hot, and 3) even when established procedures have been ignored,
and 200,000 gallons of coolant was dumped on the containment floor,
1 and 2 have kept off site release to negligible values.
The Soviets designed the RMBK reactors with the implicit idea that
no single point critical failures would occur, and that operators would
unfailingly follow proper operating procedures.
US commercial reactors are designed with the explicit idea that multiple
critical systems can fail, and that operators may take exactly the wrong
actions, even over a period of days. Despite that, the reactor must
self-damp, and containment must hold. TMI is testimony that even in
a worst case scenario loss of cooling and core melt, the design
performs as intended.
Note too that current US commercial reactors aren't the best we
know how to build. There are *intrinsically safe* designs available
which would have avoided even the core melt of TMI.
An intrinsically safe design is defined as one where you can simply
walk away from the reactor in any situation, and if operation goes
outside well defined parameters, it will gracefully shut itself down
due to basic physics principles without need for any active shutdown
This sort of reactor was a staple of college nuclear engineering
programs when I was in school. They let unsupervised undergrads
play with them. As many undergrads might, I've throttled one up
to see what she would do. Lots of heat, but no harm no foul as
far as safety was concerned, just the friendly blue glow that
reminds you Mr Atom is working for you.
Well, not exactly. The Windscale fire was a Wigner release gone wrong.
It was an air-cooled plutonium breeder reactor.
Apparently, for reasons I don't understand, the Wigner release
(a procedure that anneals the graphite moderator before the energy
stored in the crystal lattice of the graphite becomes unstable)
is not needed on water-cooled reactors, possibly due to the different
operating temperature of the graphite.
Chernobyl did have a containment structure, although due to the size of
these graphite pile reactors, it was impractical to withstand the pressures
that are required for our PWR reactors. A massive rupture of the
cooling water pipes, with the flashing of tons of water into steam
in seconds would likely have burst ANY containment structure.
The key is that at the time the bar-betters blew the plant up,
it was ready for a fuel replacement, and the fuel in this type of
reactor is VERY unstable. Any reduction in the neutron damping of
the reactor could cause a wild increase in power output. And, a
temperature spike and boiling of the cooling water was enough to
raise the reactor to 10 or more times full power output within seconds.
They produced the dreaded "superprompt hypercriticality" that is supposed
to be practically impossible in our PWR designs.
Oh, the bar bet thing: The operators, without consulting anyone who
might have known what could happen, were wondering how long they could
keep power in the station only on the inertia of the turbo-alternator.
So, they went off grid, and then shut off the steam to the turbine.
As the alternator slowed, the power frequency slowed down, and all
pumps slowed down. The reactor, just down from full power operation, was
still very hot, and they needed full cooling water flow to keep the
water from boiling in the pipes. When the water boiled, it kept
water from entering the pipes, and the reactor came back to producing
nuclear power very quickly, and then went out of control. With the
fuel at that advanced state of burn, there was no way to stop the
runaway reaction. All control rods were alredy fully inserted.
Yes, but this is at the center of the asphalt. it was noted to be
twice that at the edge of the road, and 5-6 times higher in the
Note she won't ride with anyone else, because she doesn't want anyone
else stirring up dust that she will breathe or get on her.
With one interesting exception. DOE's N reactor
at Hanford, Washington. It was a dual-use reactor,
producing plutonium and supplying power to the grid.
Water cooled, graphite moderated, *no* containment.
The argument can be made that it was a commercial
reactor as it's power was sold to the grid.
N reactor was shutdown for safety upgrades in '87
and then put into cold shutdown in '88. It hasn't
Yeah, but that's still well below what the scientific community
considers acceptable exposure. See the article I referenced.
I got the impression that the main reason is just that she likes to ride
alone through an area with no people and no traffic. Her main complaint
about getting dust on herself and her bike was that the chemical
decontamination she'd be forced to endure when leaving the area in
that case was hard on the paint of her Kawasaki.