U.S. Sen. Susan Collins says repair costs to a nuclear-powered attack submarine that was severely damaged by a fire at Portsmouth Naval Shipyard will come in within $50 million of the original estimate. Kevin Kelley, the Maine senator’s spokesman, said Wednesday that the Navy’s revised repair estimate for the USS Miami comes in plus-or-minus $50 million of the original estimate of $400 million for repairs and another $50 million in ancillary costs. The Miami was damaged in a fire May 23 while undergoing an overhaul at the Kittery, Maine, shipyard. Twenty-four-year-old Casey James Fury, of Portsmouth, N.H., has been charged with two counts of arson for setting the May 23 fire and a second blaze outside the sub on June 16. Repairs are expected to be completed by April 2015.