Supplement No. 1 to the Safety Evaluation Report by the Office of Nuclear Reactor Regulation, U.S. Nuclear Regulatory Commission, in the Matter of Ohio Edison Company, Toledo Edison Company, Cleveland Electric Illuminating Company, Duquesne Light Company, and Pennsylvania Power Comapany, Erie Nuclear Plant, Units 1 and 2, Docket Nos. STN 50-580 and STN 50-581