WASHINGTON (Sputnik) — In September 2015, the NNSA and the Department of Defense estimated the B61-12 life extension program would cost about $8.9 billion, the report noted.
"NNSA [Nuclear National Security Administration] is… working to ensure future compatibility with the F-35 aircraft," the report, issued on Thursday, said. "NNSA and Air Force officials said they will not know for several years whether steps planned to manage these risks are adequate."
"Remaining risks include the risk that components may fail in certain flight environments and risks related to testing of certain nonnuclear components," the report acknowledged.
A tight development and production schedule which the US Nuclear Weapons Council has described as having "little, if any, margin left" complicates efforts to manage risks, the GAO added.