NRC’s Requirements Following Entergy’s Announcement Palisades Will Cease Operation

Viktoria Mitlyng
Senior Public Affairs Officer
Region III

Entergy announced last week it would permanently shut down its Palisades Nuclear Plant on October 1, 2018. The facility, located in Covert, Mich., has been in operation since 1971 and is licensed to operate until 2031.

palisades_smallThe NRC was not involved in the decision, which the company said was based on business and financial factors. Our single focus as an independent regulator is on the safety of nuclear plants, the public and the environment.

However, once any announcement about closure is made, the NRC becomes engaged and the company has to meet our requirements for permanently shutting down an operating reactor.

The first step in this process requires Entergy to make a written Certification of Permanent Cessation of Operations to the NRC within 30 days from announcing its decision to permanently take the plant off line.

Should Entergy decide to continue operating the plant beyond the date stated in the certification, it would have to notify the NRC in writing.

As long as the plant is operating, we will continue to independently verify Palisades is meeting NRC’s stringent requirements. These requirements will remain in place until all fuel is removed from the reactor and the NRC has the company’s certifications of permanent cessation of operation and permanent fuel removal. At that point in the process, Entergy is no longer authorized to put new fuel into the reactor or resume plant operation.

The plant then enters the NRC’s well-established decommissioning process  geared towards ensuring the continued safe use of nuclear material, and the safety of nuclear workers and the public. Decommissioning must be completed within 60 years of the plant ceasing operations.

Nuclear plant operators are required to plan for the ultimate decommissioning of the plant before it begins operations by establishing and maintaining a dedicated decommissioning fund. These funds – created to ensure there will be sufficient money to pay for a plant’s radiological decommissioning — cannot be used for any other purpose unless the NRC grants an exemption.

Operating plants must maintain the required levels established by the NRC  and certify that there is reasonable assurance there will be adequate decommissioning funds, at least every two years while the plant is operating and more frequently after it ceases operations. The NRC reviewed the decommissioning funding status report  for Palisades in 2015 and found that it met our requirements.

An Inspector’s Perspective On the Control Rod Drive Mechanism Housing Flaws At Palisades

Elba Sanchez Santiago
Materials Engineering Inspector
NRC Region III
Elba Sanchez Santiago is a Materials Engineering Inspector in the NRC's Region III.
Elba Sanchez Santiago is a
Materials Engineering Inspector in the
NRC’s Region III.

There has been a lot of interest lately in the flaws that were recently found in the control rod drive mechanism (CRDM) housings at the Palisades nuclear plant, near South Haven, Mich. I want to share my direct experience with the NRC’s thorough and independent evaluation of this issue.

First, some background. The control rod drive mechanism moves control rods inside the reactor to control the level of nuclear chain reaction. The housing is a metal tube around the control rod drive mechanism, which is connected to the control rod and prevents leakage of reactor water into containment.

According to a commitment made in 2012, the plant conducted inspections of 45 CRDM housings in this reactor and found flaws in 17 of them. Palisades committed to these inspections after the discovery of a crack in one of the housings resulted in a plant shutdown in 2012.

Because of my expertise as a materials engineering inspector, I was dispatched to Palisades after it shut down in 2012. I was to evaluate the plant’s response to the discovery of the through-wall crack. As a member of a special inspection team that further evaluated this issue, I reviewed the plant’s testing of eight additional CRDM housings and their corrective actions. Even though no other cracks were found, the plant committed to further evaluate the condition of the housings during the 2014 refueling outage.

I came to Palisades before the current outage started to evaluate the site’s inspection methodology, work procedures, tooling and personnel qualifications. When the examinations started, I observed some of the actual testing and evaluated the results. To date, there is no evidence of leakage resulting from the flaws. I will remain onsite providing oversight over the plant’s actions until the issue is resolved.

Since the issue first came to light in 2012, I have been working with a team of other inspectors and specialists in Region III and the headquarters office in Rockville, Md., to make sure we ask the necessary questions to understand the plant’s methodology and assessments, and independently verify the conclusions.

Our in-depth independent reviews will continue until the plant completes the necessary repairs and takes proper actions to make sure the CRDM housing flaws do not lead to a significant safety concern. The results of our inspections will be documented in a publicly available inspection report.

Palisades Tank Leak Repaired — Safe to Restart

Prema Chandrathil
Region III Public Affairs Officer

palisades_smallAfter intense NRC scrutiny that confirmed the plant is safe to operate, the Palisades nuclear power plant in Michigan restarted Monday after more than a month shutdown.

In total 10 NRC inspectors performed a wide range of inspections to ensure the leak in a refueling water tank, the reason for the shutdown, was fixed.

Entergy employees identified a leak from the tank on May 5.The leak exceeded the level Entergy had committed to the NRC, which required the plant to shut down to ensure structural integrity of the tank.

The tank is used during refueling outages and to supply water to the reactor during emergencies. It has leaked before. That’s one reason why, in a July 2012 letter, the plant made a commitment to measure and trend daily leakage from the tank, and shut down the plant if the leak exceeded certain limits.

The NRC responded quickly once the leak was reported. The resident inspectors headed into the plant that Sunday, May 5, to closely follow Entergy’s actions to shut down the plant and inspect their efforts to identify the leak. We also sent a specialist with a background in materials engineering to further inspect the plant’s detailed actions to identify and repair the leak.

And we had additional inspectors review and assess the plant’s test and repair plan, look into the area beneath the tank, understand and analyze the stresses on the tank, review the root cause of the leak, and observe the actual welding and testing of the tank components.

NRC’s Region III also continued our commitment to openness and transparency by publicly documenting phone call discussions between Entergy and NRC management on this issue. Additionally, the region held a webinar on radioactive releases during which Region III staff addressed the public’s questions and concerns about the tank leak. More than 70 people participated in the webinar.

Going forward, the NRC will continue to make sure the tank remains safe. We will independently inspect the areas around the tank where leaks can be identified and will follow Entergy’s actions to monitor the tank. If small leaks are discovered we expect Entergy to evaluate them according to the NRC’s rules, and take appropriate action.

We have received dozens of calls and inquiries about this issue. We want to assure you that the public and plant workers continue to be safe. We remain committed to being open and transparent about issues of concern to the local public. To that end, we will hold an internet event to discuss NRC regulations regarding this tank and why Palisades was safe to restart. Once a date has been determined details will be posted on the NRC website.

How the NRC is Responding to the Cooling Water Leak At the Palisades Nuclear Plant

Prema Chandrathil
Region III Public Affairs Officer

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.

palisades_smallFor 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.

NRC Hosts Webinar on Palisades Leaks


Viktoria Mitlyng
Senior Public Affairs Officer
Region III

We gathered at the NRC’s Region III office near Chicago on a recent Saturday morning to continue our dialogue with the public about the Palisades nuclear plant. We decided to host our second webinar on this plant on a Saturday in response to a request from members of the public to hold it at a time when people aren’t at work.

Close to 100 people listened to the NRC’s presentation by four representatives of the Region III staff and asked questions on a wide range of questions on recent problems at Palisades.

The purpose of the webinar was to talk about the NRC’s regulations on a specific category of leaks – including the leaks that occurred at Palisades in 2012 – and the NRC’s response to these leaks. They are called “through-wall” leaks because they come through the wall of pipes and other plant components important to safety.

Resident inspectors stationed at every nuclear plant in the country continuously monitor any such leaks making sure they are properly understood and handled. Leaks that have no safety impact are not regulated by the NRC.

NRC’s regulations on through-wall leaks are based on the safety significance of the affected equipment. Leaks from the pressure retaining boundary of the reactor coolant system are not allowed and must be fixed right away. Other types of leaks may not require immediate repair but must be fixed before they have a negative impact on plant safety.

We talked about four through-wall leaks identified at Palisades last year; one of these was discovered by an NRC Resident Inspector during a routine daily inspection. Even though these leaks did not compromise plant safety, they concerned us because of their frequency. The agency decided to commit additional resources this year to evaluate these leaks and determine whether they represent a weakness in the plant’s maintenance program.

Three of the four leaks at Palisades have been fixed. The remaining leak from a refueling water tank is closely monitored and will be repaired according to NRC regulations.

We informed the public when the leaks at Palisades were discovered even though the NRC doesn’t normally make public notifications on leaks of very small safety significance. This was done in response to requests from many people to be informed about such issues at the plant.

We will continue the high level of engagement with the public near the Palisades plant to meet the agency’s goal of openness and transparency. Additional webinars on reactor vessel head embrittlement and environmental monitoring are already in the works. In addition, the NRC staff will have a booth at the Garden and Leisure Show in Benton Harbor, Mich., March 15-17.