The construction of protective structures for key facilities at the Zaporizhzhia nuclear plant in southeast Ukraine is nearing completion, Russia’s state TASS news agency reported on Tuesday, citing an adviser to the head of Russia’s nuclear plants operator.

The Zaporizhzhia nuclear power plant, Europe’s largest, was captured by Russian troops in March of last year, in the opening days of Moscow’s invasion in Ukraine. It remains close to the frontlines, and has repeatedly come under fire, raising fears of a nuclear disaster.

“The erection of engineering and construction structures, which are designed to provide additional protection for important nfrastructure facilities of the nuclear power plant, including those related to the storage of radioactive materials, is at the completion stage,” TASS cited Renat Karchaa of Russia’s nuclear plants operator Rosenergoatom as saying.

Karchaa did not provide any other detail about the structures. In December, Russia said it had set up a shield over a storage site for spent nuclear waste at the plant.

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The International Atomic Energy Agency (IAEA) had been working on establishing a safe zone around the plant, but it said earlier this year that brokering a deal on the zone was getting harder. Karchaa said there had been no shelling at the plant since the beginning of the year.