NASHVILLE, Tenn. (AP) — Tennessee officials say the heat is back on for almost the entire Tennessee prison that lost its main heating source on New Year's Day. Tennessee Department of Correction spokeswoman Alison Randgaard said Thursday morning all of Riverbend Maximum Security Institution is expected to have boiler-produced heat within 24 hours. Amid frigid weather, Randgaard says portable heating units have kept affected areas between 60 and 70 degrees.