ALBUQUERQUE, N.M. - Two computer disks that supposedly disappeared last summer, prompting a virtual shutdown of the Los Alamos National Laboratory, in fact never existed, according to a report released Friday. In a harshly worded review that described severe security weaknesses at the nuclear laboratory, the U.S. Energy Department concluded that bar codes were recorded for the disks but that the disks themselves were never created. A separate FBI investigation supported that finding, according to the report. “The weaknesses revealed by this incident are severe and must be corrected,” said the report. As punishment for the problems, the Energy Department...