Back in august the Three Mile Island shut down for 12 days. It shut down yesterday after a malfunction in one of the four reactor coolant pumps. Officials will not say how long the plant will be shut down.
The TMI alert group says as a condition for re-licensing all plants need to have an aging management program in place to monitor aging equipment and parts.
The last time TMI was re-licensed was in 2009.
TMI officials say they have one and are following it, but this watch group says it is concerned that the plant is not functioning as it should.
"Anytime a plant shuts down on short notice it normally releases radiation. This is not good radiation is cumulative in nature it's going to take some time to reconstruct the even and see how much was actually released. The way to prevent this from occurring again is to make sure all the parts in the plant are operating as they should." Says Eric Epstein, TMI Alert.
Three Mile Island officials tell CBS 21 news since the plant opened, its made more than 600 million dollars in investments to completely give it the upgrade it needs to continue running.