March 9, 2010
Aging Reactors Put Nuclear Power Plant 'Safety Cultures' in the Spotlight
By PETER BEHR of ClimateWire
On Nov. 4, 2008, two divers were cleaning sludge and silt from an entry bay for water pumps that serve Constellation Energy Nuclear Group's Nine Mile Point nuclear power plant near Oswego, N.Y.
In the midst of the operation, the diver and the hose tender shifted their positions and the diver lost control of a plastic suction hose, leaving its trailing section in front of one of the water pipe entries. The force of the water flow, at 9,000 gallons a minute, severed a section of hose and sucked it into one of the system's pumps, fouling it. As the team tried to cope with that problem, a smaller piece of the unattended free end of the hose was pulled into a second water pump, according to an inspection report by the Nuclear Regulatory Commission.
A sudden blockage of cooling water is one of the potential nightmares that nuclear power plant operators and regulators fear most. Although these pumps did not provide cooling water directly to the reactor, they supported other essential equipment, and in this case, other pumps were working. The incident did not create a safety threat to Nine Mile Point's No. 2 reactor, the NRC concluded.
But the NRC did find "significant weaknesses" in CENG's investigation of the incident and the corrective actions it took initially. The operators on duty did not look hard enough to understand the extent and severity of the incident, nor ensure that the pumps were operational after hose intrusion, NRC inspectors later determined.
Across the U.S. nuclear energy sector, plant owners are seeking -- and gaining -- NRC approval to run first-generation plants for 20 years beyond the original license period. Nine Mile Point Unit 1's operating license has been extended to 2029, and Unit 2 is cleared to run until 2046....
http://www.nytimes.com/cwire/2010/03/09/09climatewire-aging-reactors-put-nuclear-power-plant-safet-15798.html?pagewanted=print