The International Atomic Energy Agency has reported that "a small water leakage was detected from an impulse line - essentially a small pipe - connected to" Zaporizhzhia nuclear power plant's first unit’s primary circuit, with repairs taking place and no "immediate issue for nuclear safety".

According to the update from the IAEA, the repairs required the pressure in the primary circuit to be decreased to atmospheric levels and the operators of the plant - which has been under Russian military control since March 2022 - told them on Thursday the welding work had been completed and radiography checks of the welds were on-going.

Director General Rafael Mariano Grossi said: "The agency will continue to follow this issue closely, although we don’t see any immediate issue for nuclear safety. In general, we have identified regular equipment maintenance - which is vital to ensure sustainable nuclear safety and security - as a challenging area for the Zaporizhzhia nuclear power plant during the conflict."

All six of Zaporizhzhia's units have been in cold shutdown and, following this shutdown for maintenance, unit 1 is expected by the IAEA to be put back into cold shutdown.

The operators of the plant said on Telegram that a "microcrack in the pipeline was discovered and promptly eliminated", and after testing has confirmed the successful repair "it will be put into operation". The update added that radiation levels at the plant and surrounding area was unchanged.

The IAEA has had experts stationed at the Zaporizhzhia plant for more than two years, seeking to protect nuclear safety and security at the site, which is close to the frontline of the Ukrainian and Russian forces. The IAEA says the current team at the plant "continue to hear explosions daily, although no damage to the plant was reported".

There are also IAEA teams at Ukraine's three other operating nuclear power plants, with those at Khmelmnitsky reporting that drones had flown within 400 metres of the plant. Grossi said: "Frequent reports of drones flying near nuclear power plants continue to be a source of deep concern for nuclear safety and security. As we have stated repeatedly, any military activity in the vicinity of nuclear power plants represents a potential risk."