California Code, Public Resources Code - PRC § 25520.5

(a) In reviewing an application for an additional facility at a potential multiple-facility site, the commission shall undertake a reconsideration of its prior determinations in the final report on the notice for the site issued pursuant to Section 25514, based on current conditions and other reasonable and feasible alternatives to the proposed facility.

(b) Within 180 days of the filing of the application for an additional facility at a potential multiple-facility site and after adequate public hearings, the commission shall issue its decision on the acceptability of the proposed facility based on the reconsideration specified in subdivision (a) of this section.  A negative determination shall be the final decision of the commission on the application and subject to judicial review pursuant to Section 25531.  An affirmative determination shall not be a final decision of the commission on the application.

(c) The decision of the commission on an application for an additional facility at a potential multiple-facility site receiving a favorable determination pursuant to subdivision (b) of this section shall be issued within 24 months after the filing of the application or at such later time as is mutually agreed upon by the commission and the applicant.