The Russian State Investigation Committee said on Friday that a hidden explosive device detonated when the man got into his car.
The attack took place in the city of Enerhodar, where the power plant employees lived.
Ukrainian military intelligence has confirmed the attack and called the dead man a collaborator who had taken part in reprisals against nuclear power plant employees loyal to Ukraine.
The man had also been the chairman of the Enerhodar city council, which was appointed by the occupying power.
The Zaporizhzhya nuclear power plant is the largest nuclear facility in Europe and has been occupied by Russian troops since March 2022.
The six reactors have been shut down, but still need to be cooled and maintained.
There have been frequent explosions in and around the plant, for which both sides blame each other.
The staff members of the International Atomic Energy Agency (IAEA) are on site and monitoring the situation. (dpa/NAN)
