The contractor charged with cleaning up the most dangerous waste at the Hanford Nuclear Reservation in Washington state said yesterday that the cost would likely be $15.2 billion, up from an estimate of $13 billion earlier this month, which was up from an original estimate of $6.9 billion. British Nuclear Fuels, the contractor, admitted that the cleanup of Hanford’s highly radioactive nuclear waste storage tanks may simply not get done because of the projected expense. Earlier this month, Mike Lawrence, the general manager of the cleanup project, resigned, saying he was frustrated that he didn’t have direct control over key portions of the program. Hanford, the most contaminated site in the U.S., has 54 million gallons of radioactive waste leftover from the production of plutonium for nuclear weapons.