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system, or ECCS. This system is
supposed to deliver coolant to a re–
actor core if the primary coolant is
lost, keeping the reactor from over–
hcating and melting, which could
cause the release of radioactivity.
Scientists have specu lated what
The
Risks
lnvolved
might happen if
one of the pipes
in the ECCS car–
rying the cooling
A
RE :mE
risks !nvolved in
~evel
oping atom1c energy JUStl–
fied by the enormous potential ben–
efits?
Says Dr. Thomas Cochran, a spe–
cialist in nuclear energy. "Frankly,
when I look at the potential risk,
1
can only conclude that the risk is
not worth the taking."
Just what are the risks involved,
anyway?
"Acts of God"
The area of greatest concern
apart from reactor safety. potential
for sabotage, and waste disposal in–
volves "acts of God" - i.c., earth–
quakes. In
1971
ata conference in
Carmel, California. an AEC execu–
tive admitted: "When an earth–
quake occurs near a nuclear power
plant, every feature of the plant will
be affected to sorne degree by the
earthquake. Complex multiple fail–
ures may occur. Ifthe nuclear power
plant is not adequately designed
and constructed to withstand the
earthquake effects, the potential exists
for the concurrent loss of fue! integ–
rity and the loss of function of the
redundant sys tems and barriers
which preventradioactivity release."
The AEC does its best to see that
reactors are not built near recently
active earthquake faults. But sorne–
times fault lines are not discovered
until after construction has begun.
Nuclear Blowdowns
Another recent controversy in–
volves the emergency core cooling
PLAIN
TRUTH September 1974
water ruptured.
lf a majar cooling pipe ruptured,
resulting in a "blowdown," or loss of
water pressure in the cooling sys–
tem, would pressures in the reactor
core build up so fast that the emer–
gency cooling water could not enter
the core?
Would the meltdown result in the
pressures damaging the reinforced
concrete dome above? Would the
melted core drop down to the con–
crete fioor below. and even melt
down into the earth - a condition
referred to as the "China syn–
drome"?
Unfortunately, there is a paucity
of data to know just what would
happen in such an event since no
reactor has been melted down all
the way.
A reactor at ldaho Falls has been
set up to explore the loss of coolant
possibilities. lt will study engineered
safeguards in a water-cooled reactor
by deliberately causing a majar
coolant pipe rupture - the worst
conceivable accident for such reac–
tors.
It is possible that computer mod–
els and LOFT (loss of fluid test)
reactor studies will cause modi–
fications in future and even in sorne
existing reactors. In the future. sorne
prcssurized water reactors may just
have to operate at lower levels of
power.
What, then, is the risk involved in
a majar water pipe rupture?
A recent pioneer study done by
Dr. Chauncey Starr and experts
from the University of California.
comparing nuclear plants with fossil
fuel plants. found that smallleaks in
high-pressure pipes in fossil fue!
plants are really fairly common. Nu–
clear plants. of course, are much
more stringently inspected and rig–
idly constructed. Starr estimated
that the rupture rate of a reactor
pipe would be one in one million
reactor years. He concluded that a
minor break leading to release of
radioactivity into the environment
would occur once in one hundred
million years.
· Even then, only a small part of
the radioactivity would be carried
away from the immediate area of
the nuclear plant. Under normal
weather conditions, the result would
be perhaps
5,000
extra cases of can–
cer in ten years for a city the size of
Los Angeles - an increase in cancer
fatalities of about three percent.
This, of course, would be
5.000
too
many.
Dr. Starr's study concluded that
power plant perils are comparable
to the dangers of being struck by
lightning or being bitten by a ven–
omous animal or insect.
An AEC report published in
1973
estimated that a major accident in–
volving a release of about
10
curies'
of radioactivity in a given reactor
would occur less than once in
100
billion years.
Dr. Herbert Koutz, the AEC's
diTector of reactor safety research,
commenting on the preliminary
results of a more recent study,
said the odds of a majar catas–
trophe were once in one billion to
ten billion years. Such odds, he
said, "are so low as to be negli–
gible."
o
'A curie is a unit of measurement of quan–
tity of radioactivity . One curie is the
amount of radioactive substance thaL un–
dergoes
:n
billion disintegrations
p<'l'
sec–
ond.
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