Operators took a reactor at Pennsylvania’s Susquehanna nuclear plant offline Tuesday to fix a small coolant leak.In a report to the Nuclear Regulatory Commission, the plant described leakage into the drywell as being caused by a leak at a “welded joint on the 'A' reactor recirculation piping where a 4 inch blank-flanged pipe for chemical decontamination connects to the 28 inch pipe.”Unit 2 remains online. Both are General Electric Type 4 boiling water reactors. The plant northeast of Harrisburg, Pa., is operated by a subsidiary of PPL.In a statement, PPL Chief Nuclear Officer Timothy Rausch said the condition did not affect public safety. "We made the prudent decision to shut down the unit while the leak is small and will return it to service after we make the needed repairs," he said.