The nuclear plant in Paks, south of Budapest, provides around 40 percent of Hungary's annual electricity generation.The operator of the plant, whose four reactors built with Soviet-era technology are cooled by water pumped from the Danube, warned earlier that a shutdown was "unavoidable".

Prime Minister Peter Magyar has said the nuclear plant will probably shut next week © Attila KISBENEDEK / AFP

"According to current calculations... this could happen on Tuesday or Wednesday," Magyar told a press conference at the plant, which has already reduced output in recent days.The Danube has dropped to record low levels in some parts because of prolonged rain shortages and successive heatwaves since May.Romania has already shut one of its nuclear reactors for the same reason and has announced it would close the second.The shutdowns are just one effect of an already record-breaking spell of hot weather, with several countries taking steps to reduce the risk of fires and ease pressure on water and energy networks.'Unbearable'Hungary's government has called on businesses to use less electricity, banned outdoor fires and ordered decorative lighting on state buildings to be switched off to save energy.Kata Serfozo, 36, a designer on maternity leave in Budapest, said she was spending "a lot of time outdoors in the shade" because it feels better than staying at home with "the curtains drawn, the blinds down, and the shades closed".