Samuel J. Collins, a regional administrator with the NRC, said in a statement the performance of humans and machines during the outage need to be looked into more closely.
"While the plant was safely removed from service during the event, several equipment issues arose during the shutdown that we believe bear closer examination," he said. "Through this special inspection, we intend to gain a better understanding of these issues, including the actions taken by plant operators in response."
Among those was an electrical component failing; an emergency diesel generator taking longer than expected to start; and problems involving an isolation condenser, a component used to help cool down the reactor during shutdowns.
David Benson, a plant spokesman, said the backup generator did not perform as expected.
"We are not satisfied with the performance of one of the two diesel generators," he said. "Our expectation is for the generator to start up in seven seconds; this generator took 80 seconds."
Oyster Creek is the oldest nuclear reactor in the nation and just received a new 20 year license this past April. But this isn't the only problem to crop up since then either:
