The International Atomic Energy Agency (IAEA) was informed that on 9 August 2024, TEPCO found a water leakage at Fukushima Daiichi Nuclear Power Station Unit 2, involving an estimated 25 tons of water from the spent fuel cooling system pump room and the heat exchanger room. The leaked water flowed into drain on the floor connected to the water collection pit (floor sump) located in a room of the first basement floor. The Agency was also informed that TEPCO has not found any leakage spread to other rooms at this stage.
As precautionary measure, TEPCO stopped the spent fuel primary cooling pump in order to investigate the cause and evaluated the temperature level at the pool. TEPCO confirmed that the temperature is within normal range and not above around 46 degrees Celsius. This is below the 65 degrees Celsius limitation of operation. The level of accumulated water in the room had stopped rising, and therefore determined that the water leakage had stopped.
The leaked water was accumulated in the first basement floor as stagnant water. The level of water was lower than the sub-drain water level around the building, which means the leaked water remained inside the building. TEPCO will treat the leaked water through its water treatment facilities.
TEPCO continues to monitor Unit 2 spent fuel pool and water level, and will make an investigation into the leakage and the future countermeasure to decide the repairing plan utilizing a remote control robot.
It is important to highlight that this event is not related to the ALPS treated water discharge. It happened inside the Reactor Building of Unit 2. The Agency was not informed about any breach of the radiation protection standards.
The Director General will continue to keep Member States informed of further developments, as appropriate.
