Shikoku Electric Power Co. said it pulled out one of the 16 MOX fuel rods from the No.3 reactor of its Ikata plant in Ehime Prefecture at 11:57 p.m. on Monday as part of maintenance work.

MOX fuel is made of plutonium and uranium extracted while reprocessing spent fuel and is a key component of resource-poor Japan's nuclear fuel recycling program. Using such fuel is also important for the country to reduce its stockpile of plutonium, which can be used to make nuclear weapons.

The No. 3 unit restarted operations in 2018 under stricter safety regulations introduced after the 2011 Fukushima nuclear crisis led to a nationwide halt of nuclear power plants. The reactor is among several rebooted units using MOX fuel.

Shikoku Electric plans to complete the removal of the 16 fuel rods within a few days and will load five new MOX fuel rods as part of the reactor's periodic maintenance work that started on Dec. 26.

The spent MOX fuel rods will temporarily be stored in a cooling pool at the plant, since there are no reprocessing facilities in Japan at present. It is unclear where the fuel will end up. Spent MOX fuel tends to be hotter than the low-enriched uranium more widely used in thermal reactors.

The removal work had been delayed after the power company found one of the 48 control rods in the No. 3 reactor was mistakenly pulled out during the preparation work on Sunday.