Excessive wear in Southern California\u2019s nuclear power plant steam generators could lead to more toxic radioactive releases into the environment, Nuclear Regulatory Commission staff noted Jan. 7. Federal regulators investigated the unusual wear at the 2,100 MW San Onofre Nuclear Generating Station--elevating it to a commissioner level during the hearing. Calling the issue \u201ctechnical,\u201d commission chair Allison Macfarlane also noted the steam generator investigation is significant in the process of a potential trial restart of one of the facility\u2019s units. Plant operator Southern California Edison is requesting a trial restart for unit 2 at 70 percent power for five months. Unit 1 released radioactivity due to steam generator malfunction in January 2012. There is no recommendation for a future restart of that reactor. The steam generators were replaced in 2010-2011 at a cost of $670 million. When Macfarlane asked regulatory staff what\u2019s the \u201cworst that could happen\u201d if San Onofre\u2019s steam generators fail, Eric Leeds commission director, Office of Nuclear Reactor Regulation, said steam tube degradation could \u201cpossibly\u201d release radiation \u201coffsite.\u201d But, San Onofre didn\u2019t cross that line while operating, according to staff. \u201cWe concluded that it\u2019s within acceptable lines,\u201d said Ken Karwoski, NRC senior advisor, steam generation integrity. Although unit 3 of the nuclear facility released radioactivity in January 2012 due to excessive steam generator wear, \u201cThe public wasn\u2019t put in any risk,\u201d said Chris Jackson, commission chief, containment. Edison is petitioning the commission to restart unit 2 at 70 percent power for five months. The commission is still considering the plan. It expects to make a decision this spring. With a potential for restart, both units are running a \u201cfever\u201d and \u201cshould be in intensive care,\u201d said Daniel Hirsch, Committee to Bridge the Gap director. He alleged that not only the damaged unit 3 is unsafe, but also the potentially restarted unit 2.