Officials at Los Alamos National Laboratory say the estimate for fixing the new but inoperable security system at the nation's bomb building lab has doubled. Lab officials Friday confirmed a report in the Albuquerque Journal that it could cost an additional $41 million and take six months to fix the $213 million system, which has been under construction for seven years and was supposed to be complete this summer. In a memo to staff this week, lab director Charles McMillan called performance on the project "unacceptable" and said it has damaged the lab's credibility.