On Friday, the Palisades plant in Covert, Mich., shut down so plant personnel could find and repair a leak somewhere in the reactor’s cooling water system. Soon after, the NRC dispatched an additional inspector from the Regional III office, located in Lisle, Ill., with a background in mechanical testing and repairs. He supplements the two NRC resident inspectors as they evaluate the plant’s repair activities.
For more than a week now, the NRC resident inspectors on site have been following the actions taken by workers at Palisades to find the leak. The resident inspectors reviewed the data. They also watched plant workers as they isolated different parts of the system to conduct tests to try and identify exactly where the leak was coming from.
Plant workers caught the problem because the water level in the component cooling water system was going down slowly. This system uses non-reactor water to cool certain safety equipment. Per NRC regulations the system is required to be monitored. When the plant shut down the system was leaking about 35 gallons per hour. This water was captured and released to Lake Michigan through an established monitored release path. The leak did not place the plant or the public in danger.
It’s now believed a heat exchanger in the system is the source of the leak. A heat exchanger is basically a box that contains around 2,000 tubes. The tubes have water running through them to remove heat from equipment, such as seals or pumps. This heat exchanger plays an important role to cool necessary equipment during normal operation, but also during potential accident scenarios.
Palisades has two safety-related heat exchangers in this particular system; both are required by NRC regulations to be in working condition and ready to respond at a moment’s notice. With one of the two exchangers potentially not working right the plant decided to shut down before the regulations required it. NRC regulations state if there is a problem with the heat exchanger it would need to be fixed within 72 hours. If that’s not possible the regulations require the plant to shut down to find the leak and make the appropriate repairs. The plant will only be able to restart when the heat exchanger is working correctly.
Over the weekend all three NRC inspectors continued to monitor and assess the repair work to find and fix the leak. The NRC will continue to closely follow this event and observe how the plant goes about these activities with safety in mind from start to finish. We know the community is interested and concerned about these types of issues and continue to work to keep our commitment to ensure they are informed.
One of our initiatives is to provide summaries of conversations between the NRC and plant staff to the public. A summary of such a conversation about this leak, which took place on Thursday, Feb.14, will be available to the public in the near future. Our assessment of this issue will also be documented in a publically available inspection report.
U.S. NRC Blog 
Additional information can be found in the NRC’s preliminary notification and in the meeting summary of the call our staff had with the plant to discuss the details regarding this issue. The NRC does not normally summarize these types of conversations but we know the community is interested and concerned, and we want to be as open and transparent about these types of issues. Here are both numbers to search in the agency’s public document system ML13052A640 for the meeting summary and ML13053A365 for the preliminary notification we issued. Once the inspection report is complete it will also be made publically available.
Prema Chandrathil
I would like to get more detailed information on the heat exghanger leak incidents. I have a background in NPP fluid dynamics and heat transfer, as well as NPP I&C. Can you provide further information and/or references to technical issues and/or technical personnel associated with this incident.
Absolutely correct Jeff.
Of course the same logic should also be applied to San Onofre; now that the steam generators have been inspected and all worn tubes plugged, those reactors should also be up and running again.
That won’t happen either. The NRC appears to have no interest in total societal risk, only in the subset of risk attached to nuclear plants without regard to the countervailing benefit.
“with safety in mind from start to finish”
It seems to me that in the big picture it would be a lot safer to the people in the area and the environment, if the plant continued to operate, even with a small harmless leak like this, rather than replacing it’s clean electricity generation with the pollution from fossil fuels.
Shutting down the plant may be extra safe from the plant’s point of view, but in the big picture, shutting down the plant for trivial problems is incredibly damaging to the environment, when the replacement electricity generation will spew particulates and CO2 into the environment.
Get it operating again as quickly as possible.