Tepco said Saturday it has finished removing all fuel rods from the spent-fuel pool in the shattered reactor 4 building at the Fukushima No. 1 nuclear plant, in a rare piece of positive news from the decommissioning process.

A total of 1,535 fuel rod assemblies, comprising 1,331 deemed at risk and 204 that were unused, have been transferred to other buildings following a yearlong process by Tokyo Electric Power Co., the beleaguered operator of the wrecked plant.

According to Tepco, this will reduce the risk of the spent fuel rods being exposed in the event of a new earthquake or a major accident.

“Completion of the removal work is a milestone and I feel deeply about it,” plant chief Akira Ono told reporters, while stressing that the decommissioning of Fukushima No. 1 remains an extremely lengthy process.

The overall cleanup and dismantling of the plant, an operation that is expected to take decades, has been delayed by a relentless on-site buildup of toxic radioactive water.

Reactor 4 avoided a core meltdown when the tsunami spawned by the March 11, 2011, earthquake ripped through the No. 1 plant, as the unit was offline for a regular inspection and all of its fuel was stored in the pool on the upper level of the building.

But the building was torn apart by a hydrogen explosion just days later as the enormity of the nuclear crisis was only just becoming apparent. The over 1,500 fuel rod assemblies that continued to be stored at the top of the devastated structure had remained a major source of concern, in Japan and overseas.

Tepco hopes to begin extracting the fuel from the reactor 3 spent-fuel pool in the next fiscal year beginning in April, and to begin the same operation at reactor 1 during fiscal 2017. But it is unknown whether the work will follow that schedule given the sky-high radiation levels that continue to plague reactors 1 through 3, which each suffered core meltdowns, and which put the levels clocked in reactor 4 in the shade.