Resource Records 
Resource Recovery Services 
Royal Research Ship 
Reactor refueling system 
Radiation Research Society 
Radio Relay System 
Radio-Relay System 
reactor recirculation system 
Readiness Reporting System 
Recorder Reproducer Set 
Regional Research Site 
regional research sites 
Regulatory Reform Staff 
Remote Radar Station 
Remote Relay System 
Required Response Spectrum 
resonance Raman scattering 
resonance Rayleigh scattering 
Boscombe Down DERA 
Radio Range Station 
Radio Ranging System 
Radio Relay Station 
Radio Repeater Set 
Radio Research Station 
Raman spectroscopy 
Random-Random-Special 
Range Resource Scheduling 
Rapid Response System 
rate ratios 
Rational Recovery Systems