[en] Principal results of physical start-up of the WWR-K reactor (after long stop) are sited. Main aims and tasks of physical start-up are stated. Methodic supplying of tests is described. Comparison of physical testing results with expected ones got on critical stand under simulation of reactor core is carried out. Under reactor core loading by 28 five-pipe and 6 tree-pipe fuel assemblies the reactivity reserve amounted 1.62% (ΔK/K), regulating devices of system of protection control efficiency - 4.56 % (ΔK/K), emergency protection devices efficiency 1,42 % (ΔK/K). Testing results of neutron-physical parameters of reactor core and calibration results of measuring channels of protection control system in absolute power values are sited