Separately, another team of experts working under the commission has been examining earthquake faults at Ohi nuclear power plant, which houses the only two reactors currently running in Japan.
A decision is expected Sunday on whether Ohi will be shut down.
Japan's 48 other working nuclear reactors, besides the four ruined at Fukushima Dai-ichi, have not been restarted after being shut down for routine inspections.
The two at Ohi went back on line in July. Before the Fukushima disaster, nuclear power had provided about 30 percent of Japan's electricity.
Ruling party legislator Goshi Hosono, the former minister overseeing the disaster, said Saturday that more tests may be needed to check the earthquake faults, but even "a gray zone" of uncertainty would likely mean the Ohi reactors would go offline.
Japan is promising to develop renewable energy such as solar and wind power, but such a shift would take time. The cost of oil and gas imports has hurt the world's third largest economy as it recovers from last year's earthquake and tsunami.
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