SAN FRANCISCO (Standard&Poor's) Dec. 10, 2010--Standard&Poor's today assigned its 'B+' rating to Calpine Corp.'s $1 billion senior secured revolving credit facility. The company is in the process of renewing the facility with a new maturity of Dec. 31, 2015. There are no material changes to covenants from a credit perspective. The facility's recovery rating of '2' is also affirmed, indicating our expectation for substantial (70% to 90%) recovery of principal in the event of a payment default. At this level, issue ratings are one notch above Calpine's 'B' corporate credit rating. The outlook on the rating is stable. "The company is in the process of putting in place a revolving credit facility under a separate set