A report by the manufacturer of the infamous steam generators at the San Onofre Nuclear Generating Station concludes that neither the plant operator nor the maker anticipated the tubes in the plant would wear out so fast. Still, \u201cthe text supports the concern that Southern California Edison and Mitsubishi Heavy Industries rejected safety modifications to avoid triggering a more rigorous license amendment and safety review process\u201d by the Nuclear Regulatory Commission, stated Sen. Barbara Boxer (D-CA). Mitsubishi \u201crepeatedly reassured [Edison] of the efficacy of the design,\u201d according to Edison. The report \u201calso confirms that [Edison] believed the San Onofre nuclear plant\u2019s steam generators were safe when installed and that safety measures were not sacrificed for licensing reasons,\u201d the utility stated March 13. \u201cAt the time [of installation], the design was considered sound,\u201d added the utility. Edison noted there are computer code \u201cflaws\u201d that \u201cfailed to predict conditions that lead to\u201d the steam generators\u2019 excessive wear. The report, released March 8 by the federal commission in redacted form, also found that several types of vibration within the nuclear facility appeared to be causing the wear. In addition, the proposed 70 percent restart of unit 2 may or may not avoid further damage to the steam generators. A January 2012 rupture of that part of the plant resulted in a radioactive release to the environment. A proposal to restart unit 2\u2014which does not show as much damage as unit 3\u2014is being considered by the federal commission. If approved, Edison plans a trial run of the unit at 70 percent power for five months. Then, the facility\u2019s ability to continue past that time is to be evaluated. Edison operates the facility. San Diego Gas & Electric is a 20 percent owner. Ratepayers for both territories contribute to the cost of the non-operating plant\u2014at $1.2 billion in 2012. Ratepayers continue to pay off the $670 million cost, plus interest, of the steam generators, as well as other plant expenses and investments. The California Public Utilities Commission is currently investigating whether those costs should remain in the utilities\u2019 ratebases while the plant is out of service (see sidebar).