[en] Supplement No. 5 to the Safety Evaluation Report related to Commonwealth Edison Company's application for licenses to operate the Byron Station, Units 1 and 2, located in Rockvale Township, Ogle County, Illinois, has been prepared by the Office of Nuclear Reactor Regulation of the US Nuclear Regulatory Commission. This supplement reports the status of certain items that had not been resolved at the time of publication of the Safety Evaluation Report. Because of the favorable resolution of the items discussed in this report, the staff concludes that there is reasonable assurance that the facility can be operated by the applicant without endangering the health and safety of the public