A payoff scandal has struck Japan's nuclear world, threatening to delay the restart of idled reactors in what's becoming the industry's biggest crisis since the Fukushima meltdowns of 2011.

The issue, which emerged at the end of last month, centers around how an influential municipal official in a town that hosts a nuclear plant spent years doling out large gifts to executives of its operator, one of the country's biggest power producers. It's an example of how big business and small towns work together, sometimes at the expense of corporate governance.

The payments to senior management at Kansai Electric Power Co. included hundreds of millions of yen, U.S. currency, vouchers for tailored suits and even gold coins hidden in a box of candy. To make matters worse, the official in question was close to — and received money from — a company that won construction work from the utility.