The agreement will allow participating countries, including Germany, Sweden, Denmark and Poland, instant Internet access to up-to-date radiation exposure data. For example, Sweden will share its data from 37 radiation monitoring stations.
Russia has traditionally shown caution in sharing details about its nuclear programme. Russia is expected to sign the deal at a later date after winning approval from the lower house of parliament.
A Russian foreign ministry spokesman said: "There is no political reason, it's a purely technical delay."