The IAEA reports that the situation at the Fukushima Daiichi plant remains very serious.

Accumulated contaminated water was found in trenches located close to the turbine buildings of Units 1 to 3. Dose rates at the surface of this water were 0.4 millisieverts/hour for Unit 1 and over 1 000 millisieverts/hour for Unit 2 as of 18:30 UTC on 26 March. The Nuclear Safety Commission of Japan suggests that higher activity in the water discovered in the Unit 2 turbine building is supposed to be caused by the water, which has been in contact with molten fuel rods for a time and directly released into the turbine building via some, as yet unidentified path. An investigation is underway as to how the water accumulated in the trenches. Measurements could not be carried out at Unit 3 because of the presence of debris.

Fresh water has been continuously injected into the Reactor Pressure Vessels (RPVs) of Units 1, 2 and 3. From today at Unit 1, the pumping of fresh water through the feed-water line will no longer be performed by fire trucks but by electrical pumps with a diesel generator. The switch to the use of such pumps has already been made in Units 2 and 3. At Unit 3, the fresh water is being injected through the fire extinguisher line.

At Unit 1, there has been an increase in temperature at the feed-water nozzle of the RPV from 273.8 °C to 299 °C. The temperature at the bottom of the RPV remained stable at 135 °C. Temperatures at Unit 2 appear relatively stable at the same measurement points. At Unit 3, the temperature at the feed-water nozzle of the RPV is about 61.5 °C and 120.9 °C at the bottom of the RPV. The validity of the RPV temperature measurement at the feed water nozzle is still under investigation.

With the increase in temperature at Unit 1, there has been a corresponding increase in Drywell pressure. In the Drywell of Unit 2, the indicated pressure dropped slightly and is just above atmospheric.

It is planned to begin pumping fresh water into the spent fuel pool of Unit 4 today, on 29 March.

Units 5 and 6 remain in cold shutdown.