Central Japan utility received internal alerts on reactor data rigging

TOKYO - The operator of a nuclear power plant in central Japan received whistleblower reports regarding alleged manipulation of quake-resistance data but did not conduct an investigation until nuclear regulators flagged the issue last year, a source close to the matter said Wednesday.

The alleged data misconduct, disclosed a month earlier, has rocked Chubu Electric Power Co., leaving the utility with no clear prospects on when the safety screening process of its two reactors at the Hamaoka nuclear plant in Shizuoka Prefecture will restart.