Second ‘pluthermal’ reactor goes critical in Ehime

MATSUYAMA, Ehime Pref. (Kyodo) A nuclear reactor in Ehime Prefecture moved a step closer early Tuesday to starting Japan’s second “pluthermal” power generation operation with the use of plutonium-uranium mixed oxide fuel, entering a self-sustaining chain reaction, its operator said.

The No. 3 reactor at Shikoku Electric Power Co.’s nuclear plant in the town of Ikata, Ehime Prefecture, was activated at around 1:50 p.m. Monday and the self-sustaining chain reaction occurred at around 4:50 a.m. Tuesday, the utility said.

Shikoku Electric plans to start generating power at the reactor as early as Thursday morning and gradually raise its output under controlled operation. The reactor is scheduled to enter the full commercial operation phase March 30 after clearing final safety checks by the government.

Pluthermal, or plutonium-thermal, power generation using MOX fuel is a pillar of Japan’s nuclear energy policy.

The first operation started at Kyushu Electric Power Co.’s Genkai nuclear plant in Saga Prefecture in November.

The pluthermal plan at the Ikata plant has been delayed for about a week because of a minor radioactive leak and a subsequent investigation.

Shikoku Electric applied to conduct pluthermal power generation in 2004 and obtained government approval in 2006. The central and local governments approved the reactor’s quake-resistance capabilities by January.