From that standpoint, the Directive captures the two central principles of radiation protection as they apply to interventions: justification and optimization. The Directive does not appear to use the concept of practices, for which there are specified dose limits, since none are mentioned in the Directive's policy statement. This committee brought this to the attention of the Army in its interim report (IOM, 1997) in its recommendation that the Army provide soldiers the same level of radiation protection that civilians working in similar environments receive.

Several dose and dose rate levels in the Directive are associated with actions of one type or another. For example, a survey team is directed to turn back when one of its members encounters a dose rate of 0.003 milligray (mGy)/hour (0.0003 rad/hour), and commanders are to establish dose control measures as part of operations at a cumulative dose of 5 to 50 mGy (0.5 to 5 rad) (NATO, 1996). These may be thought of as reference levels—values at which certain actions should occur. ² Although it does not specifically say so, the ACE Directive assumes an underlying philosophy that corresponds closely to that of an intervention as defined by the International Commission on Radiological Protection (ICRP).

The analogy of military action as intervention is not perfect. ICRP sees an intervention as an action directed at the radiation source, for example, to prevent