There are up to four selectively applied KPPs, depending on the system. System Training and Energy Efficiency KPPs—application depends on sponsor analysis, Nuclear Survivability KPPs—mandatory for systems covered under DoDD S-5210.81, U.S. Nuclear Weapons Command, Control, Safety, and Security, Chemical, Biological, Radiological, and Nuclear (CBRN) attributes—for CBRN mission-critical systems, CBRN survivability performance attribute(s) will be evaluated to determine KPP or Key System Attribute (KSA) designation.