HOUSTON (Reuters) - Missouri Governor Jay Nixon on Friday said power companies in the state have agreed to revive plans to build a second nuclear power plant.

In a statement, Nixon said electric utilities in the state have agreed to seek an early site permit to build a second reactor at Ameren Corp's Callaway nuclear station in Callaway County, 110 miles west of St. Louis.

Partners in the agreement include Ameren's Missouri utility,

Kansas City Power & Light, a unit of Great Plains Energy; Associated Electric Cooperative Inc, Empire District Electric, the Association of Missouri Electric Cooperatives and the Missouri Public Utility Alliance.

Nixon said he will work with state legislators to pass a bill allowing the companies to recover some costs of obtaining the early site permit. The permit is only one step in the regulatory process required to construct a nuclear plant in the United States.

Friday's announcement represents a change in course for the governor and Ameren.

In 2009, Ameren asked nuclear regulators to suspend its construction application for a new nuclear plant estimated to cost about $6 billion at Callaway after lawmakers rejected a bill to allow the utility to charge customers for some costs of the new station during construction.

(Reporting by Eileen O'Grady)