The last operating reactor at the Russian-held Zaporizhzhia nuclear power plant in Ukraine has been put into what is known as a cold shutdown after an external power line was restored, making it possible to shut it down more safely.
The lack of external power to Europe's biggest nuclear plant had removed what are effectively lines of defense guarding against a meltdown at the site, which has been subject to fierce fighting in recent weeks.
What is the current situation at Zaporizhzhia, and what are the safety implications?