The Robust Nuclear Earth Penetrator
July 2005
The Robust Nuclear Earth Penetrator (RNEP): RNEP is a nuclear weapon that would burrow a few
meters into the ground before exploding and thus generate a powerful underground shock wave. Its
hypothetical targets are deeply buried command bunkers or underground storage sites containing chemical
or biological agents.
The RNEP design: Weapons designers at Lawrence Livermore National Laboratory intend to use an
existing high-yield nuclear warhead—the 1.2-megaton B83 nuclear bomb—in a longer, stronger and
heavier bomb casing. The B83 is the largest nuclear weapon in the U.S. arsenal, and nearly 100 times
more powerful than the nuclear bomb used on Hiroshima.
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Technical realities: According to several recent scientific studies, RNEP would not be effective at
destroying many underground targets, and its use could result in the death of millions of people.
2
• RNEP would produce tremendous radioactive fallout: A nuclear earth penetrator cannot penetrate
deep enough to contain the nuclear fallout. Even the strongest casing will crush itself by the time it
penetrates 10-30 feet into rock or concrete. For comparison, even a one-kiloton nuclear warhead (less
Figure 1: Fallout from the use of
RNEP against the Esfahan nuclear
facility in Iran would spread for
thousands of miles across
Afghanistan, Pakistan and India. It
would kill 3 million people within 2
weeks of the explosion and expose 35
million to cancer causing radiation.
Figure 2: Only a small region around a
nuclear explosion reaches temperatures
high enough to sterilize chemical or
biological agents. But the seismic shock
or blast wave propagates much further,
ejecting a large crater of dirt and
debris. Agents stored within the crater
volume, but outside the small
sterilization zone, would be dispersed
into the environment.
