The crippled Fukushima No. 1 nuclear power plant has seen improvements over the past three years but it will continue to be a difficult project during its decades-long decommissioning, the outgoing chief of the plant said Thursday.

Akira Ono, who headed the plant for three years until Thursday, said improvements include removing spent fuel rods from the damaged reactor building 4 and reducing the amount of groundwater seeping into reactor buildings, which then mixes with highly contaminated water.

“As for the working environment, workers can now have hot meals at a new, large rest station. In March, we were also able to widen the areas where they can work with their regular clothes” as radiation levels have decreased, Ono said.

Under the high radiation atmosphere, workers have to wear protective suits and full-face masks that are uncomfortable and make it hard to communicate with each other.

But the plant still needs to ensure facilities and equipment are operating more smoothly, and also further improve working conditions over the next two to three years in order to handle decommissioning work expected to take 30 to 40 more years, Ono said.

The Fukushima No. 1 plant faced an electric outage this week, which shut down some of the cooling facilities for its underground ice walls.

Ono said that the decommissioning work will also face other challenges, including identifying the exact location of melted fuel rods.

Shunji Uchida, who will be heading the plant from Friday, said he will spearhead efforts to create a strong foundation for the long decommissioning task ahead.

Ono takes on a new role at the Nuclear Damage Compensation and Decommissioning Facilitation Corporation, a body funded by the government and regional utilities to research technologies for decommissioning work.