31 Oct (NucNet): Thirty-four nuclear reactor units responded “well and safely” to Hurricane Sandy’s passage, proving their resilience against severe natural hazards, the US Nuclear Energy Institute (NEI) has said.
The nuclear industry group said that of the 34 reactors from South Carolina to Vermont in the hurricane’s path, 24 continued to operate safely and generate electricity throughout the storm. Seven were already shut down for refueling or inspection, and three safely shut down as designed because of storm conditions or grid disturbances.
The Nuclear Regulatory Commission (NRC) confirmed that three reactors experienced trips, or shutdowns, during the storm, but that all safety systems operated as designed. They were Indian Point-3, Salem-1 and Nine Mile Point-1.
Three plants – Millstone, Vermont Yankee and Limerick – reduced power in advance of or in response to the storm, the NRC said.
Millstone-3’s power was reduced to about 70 percent to minimise potential impact on its circulating water system due to the storm. The single-unit Vermont Yankee reduced power to 89 percent in response to a request from the grid operator due to the loss of a transmission line in New Hampshire. Limerick-1’s power was reduced to about 50 percent and Limerick-2’s to about 25 percent in response to low electrical demand on the grid because of storm-related power outages, the NRC said.
During the hurricane, Exelon Corporation’s Oyster Creek reactor in New Jersey, which was already shut down for a refueling outage, declared an ‘alert’.
The NEI said the alert, the second-lowest of four NRC action levels, was in response to high water levels at the facility’s cooling water intake structure. The NRC said the alert remains in effect as plant operators wait for the water intake levels to drop to pre-designated thresholds. The water level rose due to a combination of a rising tide, wind direction and storm surge.
The NEI said Exelon is in the process of restoring off-site power to the facility. Until then, Oyster Creek is being safely powered by backup diesel-driven electrical generators that have fuel to power the reactor’s safety systems for more than two weeks. The reactor and used fuel storage pool have ample water supplies for cooling, the NEI said.
The NRC said it is beginning to return to normal inspection coverage for nuclear power plants in the path of Hurricane Sandy, but heightened coverage will continue at Oyster Creek because of the alert.
The NEI said “careful planning and comprehensive preparations” paid off at all of the facilities.
Marvin Fertel, NEI president and chief executive officer, said nuclear energy facilities are built to withstand extreme flooding and winds that are beyond those historically reported for each area.
He said that in the days before Sandy hit the Atlantic coast, nuclear plant operators took a series of actions outlined in their emergency preparedness plans.
Mr Fertel said each plant site also has “numerous” emergency backup diesel generators that are tested and ready to provide electricity for critical operations if electric power from the grid is lost.
A summary of US nuclear plant performance during Hurricane Sandy (as of 11:00 local time on 30 October 2012) is online: