The SEG-V configuration in the RRR reactor is a benchmark system with an energy-independent adjoint flux spectrum. The neutron spectrum has been measured by means of proton recoil counters, a Stilbene scintillation technique, and a Li⁶ sandwich spectrometer. A set of activation and fission reaction rate measurements has been unfolded by the SAND-II program. The experimental results are compared with a two-dimensional spectrum calculation. Good agreement has been obtained in the most important energy range.