Pattern Side: A well-defined side of the runway at a military airport where the downwind leg of
landings, touch-and-goes, etc. take place. A pattern side could also be present at a civilian
airport if that airport is used for military aviation.
Penetration: A local damage that signifies displacement of the missile into the target and is a
measure of the depth of crater formed at the zone of impact.
Perforation: A local damage that signifies that the missile fully penetrates the target or passes
through the target.
Primary Missile: An aircraft or a detached part of an aircraft (e.g., engine) that can hit a target
directly from the air or after skidding on the ground.
Probability: A unitless quantitative measure of the likelihood of a given event with a value
ranging from 0 to 1.
Punching Shear: Local shear failure occurring in the immediate vicinity of the impacted zone.
Punching shear may occur as part of the perforation process.
REM: Acronym of roentgen equivalent man.
Respirable Fraction (RF): The fraction of airborne radionuclides as particles that can be
transported through air and inhaled into the human respiratory system. These are commonly
assumed to include particles 10Ám Aerodynamic Equivalent Diameter (AED) and less.
Respirable Release Fraction: Product of airborne release fraction and respirable fraction.
Risk: The measure of a potentially hazardous event in terms of its likelihood and the severity of
its consequences. Risk can be determined following the release analysis for specified aircraft
crash scenarios that have been evaluated for both impact and structural response likelihoods.
Prior to this step, risk is evaluated: first by inventory screening (risk's severity parameter) and
then by frequency (risk's likelihood parameter).