omaha.com — Published Wednesday February 22, 2012 By Joseph MortonWORLD-HERALD BUREAU ROCKVILLE, Md. - Omaha Public Power District officials told federal regulators Wednesday they would make no excuses for problems at the utility's Fort Calhoun nuclear plant. The facility has faced various challenges, including a fire and last summer's flooding, and it is now subject to enhanced oversight from the Nuclear Regulatory Commission.