N.C. State University officials say they have patched up a leak that shut down the campus nuclear reactor nearly three weeks ago.

The small research reactor had been leaking about 10 gallons of water an hour from a 15,600-gallon pool used to cool the superheated reactor core and radioactive fuel rods. Total leakage came to about 3,500 gallons.

The leaking water was tainted with radioactivity but posed no public health risk, university officials said. The water was presumed to flow through the Burlington Nuclear Engineering Laboratory on campus and into the ground below.