WISCASSET — The Maine Yankee atomic plant went to federal court Wednesday to challenge a move by a state regulatory agency to assert authority over high-level nuclear waste storage.

In its suit in U.S. District Court in Portland, the closed Wiscasset power plant accuses the Maine Board of Environmental Protection of exceeding its jurisdiction over plans to store spent fuel at the coastal plant site.

By a unanimous vote Aug. 19, the BEP decided it will accept public testimony on plans to store high-level waste in dry, airtight canisters that would be placed on nine concrete pads on 3 acres at the site of the defunct nuclear power plant.

The waste canisters would be secured within cylindrical concrete casks that would measure 11 feet in diameter and 17 feet high.

Maine Yankee spokesman Eric Howes said the company was filing the suit “reluctantly.” But he said the federal Nuclear Regulatory Commission should have full jurisdiction over radiological regulation at the site in order to assure safe and timely dismantling of the plant.

“We cannot have two masters on radiological issues,” said Howes.

A message left with state Environmental Protection Commissioner Martha Kirkpatrick was not immediately returned Wednesday afternoon.

Before the agency’s board voted last month, DEP Deputy Commissioner Brooke Barnes urged the board to aggressively pursue what jurisdiction it has in order to give a complete and thorough review of what will likely be the only project of its kind ever in Maine.

The board decided it will accept public testimony on the waste-storage plans, but said it would decide later whether it will rule on any issues involving the radiological implications of the project.

Howes said Wednesday that by deciding to even take testimony on the project, the state board was in effect asserting regulatory authority.