A top U.S. nuclear regulator says one of key lessons learned from Fukushima's disaster is the importance of a strong and independent operator that is transparent.

U.S. nuclear regulatory chief Allison Macfarlane, in Japan to attend the weekend's international conference on nuclear safety, told The Associated Press that utilities also must get government backing in case of a crisis.

Last year's powerful earthquake and tsunami caused multiple meltdowns and massive radiation leaks at the Fukushima Dai-ichi plant. Its operator Tokyo Electric Power Co. is struggling to keep the plant stable until it's decommissioned, a process expected to take decades.

TEPCO's internal reform panel acknowledged Friday the company neglected severe accident safety measures while it was obsessed with fixing minor safety problems to improve operational records.