Nuclear Regulation Authority's emergency information page says there is no report of troubles at the nuclear plants in the region (Ikata NPP in Ehime, Genkai NPP in Fukuoka, Shimane NPP in Shimane).
Ikata Nuclear Power Plant is located in Ehime Prefecture in Shikoku, across from the Bungo Channel that separates Kyushu and Shikoku.
Ikata Nuclear Power Plant with pressurized water reactors by Mitsubishi Heavy Electric sits extremely close to Japan's Median Tectonic Line, the largest fault in Japan, part of which is active.
The plant is one of the few nuclear power plants in Japan slated to restart after NRA finishes the reviews.
MTL, from wiki:
Location of Ikata NPP:
Earthquake epicenter, according to USGS: