This satellite photo provided by Planet Labs Inc. shows the Taishan Nuclear Power Plant in Guangdong province, China. AP
Part of Taishan nuclear power plant in Guangdong province was taken offline last July after Chinese authorities reported minor fuel rod damage and a build-up of radioactive gases at the plant.
Operators reconnected the damaged reactor after months of "inspection and maintenance", China General Nuclear Power Group said in a stock exchange filing late on Tuesday.
"The monitoring results of Taishan Nuclear Power Plant and its surrounding environment are normal," China General Nuclear Power Group said in the filing, without giving further details.
The plant is operated in a partnership with French nuclear firm Framatome and uses the European Pressurised Reactor design, which was developed to relaunch nuclear power in Europe after the Chernobyl catastrophe of 1986.
The design is touted as offering higher power and better safety, but European Pressurised Reactor projects in Finland, France and the UK have been plagued by delays and cost overruns.
There are more than 60,000 fuel rods in the reactor and the proportion of damaged rods was "less than 0.01 percent", China's environment ministry and nuclear regulator said before the reactor's closure.
They called the damage "inevitable" due to factors including fuel manufacturing and transportation.
French energy giant EDF, the majority owner of Framatome, also previously blamed the build-up of radioactive gases at the Taishan plant on deteriorating coating on some uranium fuel rods.
Official environmental monitoring data last year showed a slight increase in radiation near Taishan compared with other nuclear plants in China, but within the normal range of environmental radiation levels in Guangdong.