KYIV, Ukraine (AP) — Ukraine is considering restarting Europe’s largest nuclear plant, which is occupied by Russian troops, to ensure its safety just weeks after fears of a radiation disaster prompted its shutdown, the facility operator’s head said Tuesday.

The Zaporizhzhia nuclear power plant has emerged as one of the most worrying flashpoints in Russia’s occupation of Ukraine. It has been damaged in fighting, prompting international alarm, and its head was detained by occupying forces through the weekend before his release Monday.

Ukrainian state nuclear company Energoatom shut down the last of the plant’s six reactors on Sept. 11 because Russian military activity had cut reliable external power supplies for cooling and other safety systems, threatening a potentially catastrophic meltdown.

But now the company faces a different problem.

In an interview with The Associated Press, Energoatom President Petro Kotin said Energoatom could restart two of the reactors in a matter of days to protect safety installations as winter approaches and temperatures drop.

“If you have low temperature, you will just freeze everything inside. The safety equipment will be damaged,” he said in his office at the company’s Kyiv headquarters. “So you need heating and the only heating is going to come from the working reactor.”