A US nuclear plant exited \"alert\" status early Wednesday after the storm surge from Hurricane Sandy receded, removing the flooding threat to the plant from surging waters. The 43-year-old Oyster Creek reactor in Lacey Township, New Jersey, the country\'s oldest nuclear power plant which is operated by power company Exelon, had been shut down for maintenance ahead of the huge storm on Monday. But an alert situation -- the second lowest of four emergency classifications -- was declared as the storm knocked out the 636-megawatt plant\'s main power supply, forcing it to rely on generators, and surging waters caused by the storm threatened to top the banks of canals used to supply cooling water. The alert was cancelled after waters fell to normal levels early Wednesday and power supplies from the main electricity grid resumed, the Nuclear Regulatory Commission said. \"Station employees responded quickly and appropriately to the storm\'s challenges and all plant safety systems, including used fuel cooling, operated as designed,\" the NRC said in a statement. \"Water levels were never high enough to top the intake canal banks or impact operation of plant equipment.\" \"Additional workers are expected to return to the plant today to resume a refueling and maintenance outage that began October 22 and was temporarily delayed by the storm.\"