JEFFERSON CITY, Mo. (AP) — A pair of energy companies on Thursday announced a new attempt to expand nuclear energy in Missouri, this time by seeking federal energy funds for small nuclear reactors.

Under the plan, Westinghouse Electric Co. will seek up to $452 million from the U.S. Department of Energy in investment funds designed to support the engineering, design certification and operating licensure of small modular nuclear reactors. The utility Ameren Missouri says it then would become the nation's first power company to apply for a construction and operating license from federal regulators for a small reactor developed by Westinghouse.

Ameren plans to seek a license that would allow it to build and operate up to five nuclear reactors. The license would be valid for 40 years, and Ameren said the application process could cost $80 million to $100 million and take four years. Obtaining the license would not require Ameren to add the reactors.

Applications for money from the U.S. Department of Energy are due in May, and a decision on who wins could come this summer. But it might take until 2022 before any possible new reactors would come online in Missouri.

Ameren Missouri President and CEO Warner Baxter said the proposal could save customers millions of dollars in development costs. The St. Louis-based power company has 1.2 million electric customers, mostly in eastern and central Missouri.

"This is an opportunity that the state of Missouri simply cannot let pass by," Baxter said.

Energy company officials and elected state officials, including Gov. Jay Nixon, announced the possible nuclear energy expansion at the Governor's Mansion about 25 miles southwest of the state's lone nuclear plant, which is operated by Ameren Missouri in Callaway County. Other Missouri utilities and cooperatives back the plan.

"I can't tell you how big a deal this is for our state. This is the big one," said Barry Hart, the CEO for the Association of Missouri Electric Cooperatives. "This is going to provide jobs and economic opportunity for our state, for the people that live here, that want to raise their families here for a long, long time."

Previous attempts to expand nuclear energy in Missouri have faced criticism.

Ed Smith, the safe energy director for the Missouri Coalition for the Environment, said the state should bolster energy efficiency and renewable energy efforts rather than promote expensive nuclear power.

"The fact that we are speeding so quickly into the whole small modular nuclear reactor is so frightening," Smith said.

Another opponent of past nuclear energy proposals, the Fair Energy Rate Action Fund, called the agreement a "major victory" for consumers because it would not require ratepayers to start paying for a nuclear plant before it begins producing electricity. The group also pledged to monitor Ameren's actions closely.

Twice in recent years Ameren and other supporters have sought to clear the way for possible construction of an additional Missouri nuclear power plant. Those efforts stumbled in the Legislature amid attempts to alter a 1976 state law that bars utilities from charging customers for the costs of a new plant before it starts producing electricity.

Legislators in 2009 considered a measure that would have allowed utilities to seek state regulators' permission to include the financing costs for certain types of new power plants in consumer bills before the plant is operational. Last year, lawmakers considered a proposal to allow power companies to seek permission from the Public Service Commission to charge customers for the cost of getting an early site permit from federal regulators for a possible second nuclear power plant.

Baxter said Thursday that Ameren was putting on hold those efforts dealing with the early site permit. Officials said no state legislative action is needed for the federal licensing part of the latest proposal.

Westinghouse said a small nuclear reactor could produce 225 megawatts of electricity, about one-fifth the capacity of a large nuclear plant. The small modular nuclear reactors would be built in factories and shipped to where they are needed without altering tunnels and bridges. They are expected to take about two years to build, instead of roughly five years for larger plants.

Nixon, a Democrat who endorsed Ameren's proposal to charge customers for an early site permit, said the agreement could be an economic boon for Missouri. He said it could help ensure the state's energy needs are met while creating the potential for new manufacturing and possibly sparking a new global industry in Missouri.