U.S. NRC Blog

Transparent, Participate, and Collaborate

Tag Archives: nuclear power plants

NRC Inspectors: Free to Inspect

Diane Screnci
Senior Public Affairs Officer
Region I

We often talk about having NRC Resident Inspectors at each commercial nuclear plant acting as the eyes and ears of the agency on site. It’s important to understand how they go about their business.

Paul Cataldo

Paul Cataldo

On a daily basis, resident inspectors are attending meetings, walking down equipment, monitoring major work activities, reviewing paperwork, and talking to control room operators and plant workers. When an event occurs at a plant, the resident inspectors are in the control room, watching how operators and the plant respond. They provide first-hand knowledge of what’s going on at a plant to regional management on an on-going basis. Inspectors often work business hours, but they’re required to work evenings, weekends and overnight hours, too.

NRC inspectors, including region-based specialists, have “unfettered access,” so they can go anywhere and watch any activity they choose. NRC regulations specify that NRC inspectors must have immediate unfettered access, although inspectors must comply with applicable access control measures for security, radiological protection and personal safety. That means if an inspector wants to enter a radiologically controlled area, he or she is allowed to, but first must follow the radiation protection requirements for the area.

“My job is to ensure the company is in compliance with our regulations and their operating license, which provides reasonable assurance that the plant is safe. One approach I use is the “trust but verify” method,” says Paul Cataldo, the NRC Senior Resident Inspector at Seabook Station in New Hampshire. “In essence, having access to any document, equipment or personnel on-site, without asking permission or the licensee having prior knowledge of a request, gives us confidence regarding the integrity of the information we use during our inspections.”

Plant workers are also prohibited from announcing that an NRC inspector is at the plant or in a particular area. It’s a violation of NRC requirements and over the years we have cited plants when workers tipped off their co-workers that inspectors were on-site.

We rely on our ability to perform announced and unannounced inspections to independently evaluate plant performance. Without unfettered access, our ability to carry out our mission could be impacted.

UPDATE: Protecting Commercial Nuclear Facilities from Cyber Attack

James Andersen
Director, Cyber Security Directorate

The NRC has been very forward-thinking in developing cyber security requirements for nuclear power plants. The cyber threat is always evolving, and so is our approach. We first imposed cyber security requirements in Orders issued after the 9/11 terrorist attacks. Drawing on our experience with those steps, we formalized regulations in 2009.

Our “cyber security roadmap” spells out how nuclear plant licensees were implementing our 2009 cyber regulations, as well as our approach to assessing cyber needs of other licensees.

cybersecNuclear plants are meeting these requirements in two phases. During Phase 1, they implemented controls to protect their most significant digital assets from the most prevalent cyber attack vectors. This phase was completed in December 2012, and our inspections of Phase 1 actions were completed in 2015.

During Phase 2, which will be completed by the end of this year, licensees will complete full implementation of their cyber security programs. They will add additional technical cyber controls, cyber security awareness training for employees, incident response testing and drills, configuration management controls, and supply chain protection

Like other NRC programs, cyber security involves “defense in depth.” Crucial safety- or security-related systems (both digital and analog) are isolated from the Internet, giving them strong protection. Such “air gaps” are important, but not sufficient. Licensees must also address wireless threats, portable media such as discs or thumb drives, and other avenues of attack. Physical security and access controls, including guarding against an insider threat to the plant, also add to cyber security, as do cyber intrusion detection and response capability.

The NRC published a new regulation in late 2015 requiring nuclear plant licensees to notify the agency quickly of certain cyber attacks.

With these efforts already accomplished or underway, you can see the NRC takes cyber security seriously, and we’re doing our best to stay flexible and ahead of the ever-changing threat. You can find more information about the NRC’s cyber security program on our website.

This post first ran in October 2015

Getting Ready for Winter Looks Much Like Preparing for Hurricanes

Neil Sheehan
Public Affairs Officer
Region I

coldweatherAt first glance the blizzard that pounded the upper Midwest on Christmas weekend – or the winter storm that hit New England over New Year’s — doesn’t seem to have much in common with the hurricanes that hit the Gulf Coast or Eastern Seaboard during the hot summer months.

But from our perspective, they do.

NRC regulations requires that U.S. nuclear power plants be ready for all kinds of weather conditions, and that extends to winter storms.

The preparations take many forms. Here are some of the key activities:

  • Plant operators keep close tabs on approaching storms via weather forecasting services. Storm watches or warnings would clearly attract attention.
  • As a storm draws closer, information gathered from the facility’s meteorological towers is assessed. These data points would include wind speed/direction and snowfall rates. Specific conditions, such as wind speeds exceeding a pre-designated threshold, can result in operators starting to shut down the reactor, or reactors, at a plant site.
  • Prior to a storm arriving in the area, plant personnel would conduct visual inspections of plant grounds. They would check that there were no loose items that could be propelled by strong winds and potentially damage equipment.
  • Workers would also ensure that fuel tanks for emergency diesel generators were filled. These generators can provide back-up power for plant safety systems should the local electrical grid go down.
  • Plans would also be developed to keep the plant appropriately staffed until the storm had passed. This might mean providing cots and food for employees unable to get home due to the weather conditions.

Amid all of these preparations, the NRC Resident Inspectors assigned to each plant would follow the progress of these activities while also tracking expected conditions at the plant. They, too, could be asked to stay at the facility until the storm had passed.

The old adage that success is “90 percent preparation and 10 percent perspiration” is one taken seriously when wicked weather is bearing down.

 

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.

REFRESH — Where There’s Steam, There’s … a Steam Generator

Kenneth Karwoski
Senior Advisor for Steam Generators

refresh leafWhen the NRC talks about “steam generators,” we’re not talking about teakettles. Steam generators provide vital technical and safety functions at many U.S. nuclear power plants.

In the United States, steam generators are only found in pressurized-water reactors, one of the two types of U.S. reactors. There can be two to four steam generators for each reactor unit. The generators mark the spot where two closed loops of piping meet. The first loop sends water past the reactor core to carry away heat, and this loop is at such high pressure that the water never boils. The second loop is at a lower pressure, so the water in this loop turns to steam and runs the plant’s turbine to generate electricity.

The steam generator’s main technical job is to let the first loop pass its heat to the second loop as easily as possible. To do this, a steam generator packs thousands of small tubes closely together, allowing the maximum area for heat to pass through the tubes and into the second loop’s water.

At the same time, the steam generators provide an important safety barrier – the first loop can contain radioactive material, so the tubes must keep the two loops of water separate. NRC rules require plants to closely monitor the second loop and immediately shut the reactor down if a tube leak exceeds very strict limits.

pwr[1]The NRC’s rules for inspections, maintenance and repair of steam generator tubes help ensure the tubes continue providing the safety barrier. If an inspection shows a tube is starting to get too thin, the plant will repair or even plug a tube to maintain safety.

Steam generator tube material has improved over time. The first steam generators had tubes made from a type of stainless steel that experience showed could be corroded by the chemicals, temperatures and pressures in the first and second loop. Over time, plants have replaced those steam generators with ones using more advanced alloys that are less likely to corrode.

Steam generator replacement only happens when the reactor is shut down for refueling, and plant owners bring in hundreds of specialized workers to safely remove the old generators and install the new ones. The old generators have to be safely disposed of as low-level radioactive waste.

REFRESH is an occasional series where we revisit previous posts. This first ran in July 2013.

%d bloggers like this: