Catching Fire: Was Entergy Indian Point an environmental crisis or a lesson learned?
July 16, 2015 | By
Jaclyn Brandt
After an incident at Entergy's Indian Point nuclear power plant on May 9, 2015, the utility has finished their report on what caused it. But the bigger question of what can be learned from the experience remains.
Entergy found that the incident happened when a failure of insulation caused a main transformer at the plant's Unit 3 to short circuit and catch fire. The internal investigation by the company found that the water and foam used to extinguish the fire leaked outside the containment systems' capacity -- along with fluid from the transformer on the plant's non-nuclear side. Indian Point Energy Center is located in in Buchanan, New York, and generates around 2,000 megawatts (MW) of electricity as well as supplying power to New York City and Westchester County. So far, it looks like there may be no long-term impacts from the incident. "The transformer failure event at the Indian Point 3 nuclear power plant is not expected to have any long-term impacts on the surrounding area," Nuclear Regulatory Committee (NRC) spokesperson Neil Sheehan told FierceEnergy. "The fire was extinguished via the plant's automatic water-spray system for the transformer and by firefighters. Some of the transformer cooling oil did make overflow the barrier around the transformer and make its way into the Hudson River. However, the company brought in an environmental hazards contractor to assess the situation and work on cleaning it up." The transformer at Indian Point has since been replaced by a spare located on site, and Unit 3 has returned to service. Entergy said no remediation was warranted at most locations of reported sheens from fluids that reached the Hudson River. "We have been working closely with independent engineers, and with federal and state agencies, to address issues surrounding the May 9 transformer failure, and corrective actions are well under way," said Bill Mohl, president of Entergy Wholesale Commodities, the Entergy business unit that owns Indian Point. "These actions reinforce our commitment to environmental responsibility and transparency, as well as the continued safe, secure and reliable operation of Indian Point." Entergy worked with an independent engineering firm to conduct the report, along with their engineers -- and found that the transformer problem was related to the failure of internal insulation that caused a short circuit in a high-voltage winding coil. "Indian Point's transformers are tested routinely for signs of degradation but no immediate problems were identified prior to May 9 in the unit that failed," the utility said in a statement. "While additional forensic work on the transformer is still under way, Entergy is reviewing the initial findings to identify potential corrective actions." The teams also looked at the release of the transformer's dielectric fluid into the Hudson River and ground surrounding the plant, and found that the automatic sprinkler systems dispensed more water than the capacity of the moat containment system. "Some of this fluid mixed with firefighting water and foam, and then flowed from the moat into a storm drain leading to the plant's discharge canal and ultimately the Hudson River," Entergy said. "Contractors placed sorbent and hard environmental protective booms in and outside the discharge canal and removed fluid that had spilled in the transformer yard, storm drains and adjacent areas." At the time of the leak, the United States Coast Guard estimated around 3,000 gallons of dialectric fluid that potentially reached the river -- out of the 24,300 gallons contained in the transformer at the time. Another 8,300 was recovered from the containment moat, or was combusted. There is still an effort to look for additional leaked fluid that may still be around the area. "Contractors inspected approximately 25 locations of shoreline sheens that were reported to a New York State Department of Environmental Conservation hotline or were identified by the U.S. Coast Guard," Entergy said. "Of those, 19 locations did not require remediation. The last offsite remediation was documented as closed with the agencies on June 5. Entergy established its own hotline for the public to report sheen sightings but did not receive any calls, and it was discontinued June 29." The utility is now moving on to the next step, and are reviewing how the environmental response was handled during the incident. So far, they have determined everything they did was within regulation. Sheehan said it is still too early to discuss if the incident can teach utilities anything in the future, because NRC is continuing to investigate. "Following the transformer failure, we sent a Special Inspection team to the plant to review water found in an electrical relay room near the transformer. The team's findings should be issued sometime in the near future," Sheehan told FierceEnergy. "We are always looking for any lessons that can be learned by evaluating an event or problem. That will likewise be the case here. Among the areas to be considered will be whether the problem that led to the transformer's failure could have been anticipated and prevented, and whether the issue could affect other transformers at this or other U.S. nuclear power plants." For more:
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