The US Supreme Court said Tuesday that it won’t consider whether an appeals court improperly reopened Cotter Corp. N.S.L.’s suit seeking from the US government $15 million in costs defending radioactive material exposure litigation.

The US government in its March 23 petition for writ of certiorari argued that the US Court of Appeals for the Federal Circuit erred when it ruled that the Price-Anderson Act permitted Cotter to seek from the government costs incurred defending against litigation related nuclear material.

Allowing the Federal Circuit’s decision to stand, according to the government, would subject the government to the threat of indemnification …