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Education -->
Nuclear Facts
SECURITY
Defense
in depth
Physical
barriers
Nuclear power plant containment buildings are extremely robust
structures and, in security terminology, are considered hardened. The
defense-in-depth strategy provides for three barriers:
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Containment buildings, which house
the reactor, have reinforced concrete walls that on average are
four feet thick; |
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The reactor pressure vessel with steel walls
that are from 7 to 12 inches thick; |
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The fuel rods. |
While nuclear plants cannot be guaranteed
to be impervious to every form of attack imaginable, they are designed
to withstand hurricanes and the impact of airborne objects up to a
specific amount of force. A test at Sandia National Labs
confirmed a computer analysis of the impact of a plane crashing into a
concrete structure like a containment building. An F-4 Phantom jet was
destroyed when it hit at 480 miles per hour, while the maximum
penetration to the concrete wall was just over 2 inches.
Used nuclear
fuel
Used nuclear fuel is stored at NMC plants in water, which
cools the fuel and acts as a shield. These spent fuel pools typically
are built with four to five feet of concrete on the bottom and sides,
and are lined with a layer of steel.
At some nuclear plants, used nuclear fuel
is stored in above-ground containers. These concrete and steel
canisters are built and tested to withstand extremely severe impacts
that include hurricanes, fires, earthquakes, and acts of sabotage
without resulting in releases of radioactivity that exceed NRC limits.
Emergency
plans
Each NMC nuclear plant is required to have a
detailed emergency preparedness plan to respond to events that may
impact the plant and the public. Training for response to emergency
events is rigorous and ongoing. The exercises are monitored and the
performance graded by the NRC. Emergency plan information is provided
annually to communities near NMC plants.
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