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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.

An Explanation of Capacity Factor

Neil Sheehan
Public Affairs Officer
Region I

Earlier this year, the nuclear power industry announced it had set a record for reliability in 2015. The measuring stick for this achievement is what is known as “capacity factor.” But what exactly is that?

Put simply, capacity factor compares how much energy was generated against the maximum that could have been produced at continuous full-power operation during a specific period of time. It’s similar to baseball’s on-base percentage, which counts how many times a hitter reaches base versus the number of opportunities in the batter’s box.

Nuclear is one part of the energy generation mix.

Nuclear is one part of the energy generation mix in the U.S.

The Nuclear Energy Institute, the industry’s trade organization, preliminarily pegged the capacity factor average for all of the nation’s reactors at 91.9 percent last year. It added that this was a new record, edging out the previous one set in 2007.

An update issued by the U.S. Energy Information Administration on June 24 upped the 2015 total to 92.2 percent. EIA also lists nuclear power’s capacity factor in 2014 as 91.7 percent and 2013 as 89.9 percent.

For comparison purposes, other segments of the energy production sector had the following reliability ratings in 2015 (according to the EIA): Coal – 54.6 percent; natural gas-fired combined cycle – 56.3 percent; conventional hydropower – 35.9 percent; wind – 32.5 percent; solar photovoltaic – 28.6 percent; solar thermal – 22.7 percent; landfill gas and municipal solid waste – 67.6 percent; other biomass, including wood – 52.9 percent; and geothermal – 71.7 percent.

EIA allows visitors to its website to check capacity factors dating back to 1973. A review of this data shows that reactor reliability rates started out in the upper 40s/low-to-mid-50s percent range during the U.S. commercial nuclear power fleet’s early days.

By 1991, the level had climbed to 70.2 percent and in 1998 to 85.3 percent. Since the start of the new millennium, the capacity factor average has been in the upper 80s/lower 90s range.

Then-NRC Chairman Nils Diaz, in congressional correspondence issued in March 2001, wrote that increases in capacity factor could be attributed to decreases in the amount of time that plants were shut down for repairs, refueling and maintenance.

For its part, the NRC focuses not on the number of operational hours for plants but rather that they remain safe whether or not they are operating. The agency does, however, track the number of unplanned shutdowns as a measure of plant performance.

Five Questions With Tom Rich

Tom Rich is head of the agency’s Information Security Directorate

  1. How would you describe your job in three sentences or less?

5 questions_9with boxMy job is to work with others to protect NRC’s information and information systems. This includes providing security training, performing security assessments, testing the vulnerability of our IT systems to phishing and penetration attacks, responding to security incidents and keeping up with situational awareness to see where we may need to strengthen our defenses.

  1. What is the single most important thing you do at work?

Communication with NRC managers and employees regarding threats to our IT systems and data. We do security briefings, security awareness events for staff, and daily meetings with the Chief Information Officer.

  1. What is the single biggest challenge you face?

tomrichThe dynamic pace of technology changes and the need for cyber defenders to keep up. With the “Internet of Things” becoming more and more a part of our daily lives, the devices we now use in virtually everything we do present security and privacy concerns and introduce a much larger avenue of attack. These devices want to communicate, in some cases sensitive data, through multiple channels with each other and cloud services. The challenge is that these devices do not have adequate security controls built into their design.

  1. What would you consider one of your biggest successes on the job?

We established a cyber security dashboard that measures the NRC’s improvements in security practices. This is an internal mechanism to let NRC stakeholders see what they are doing well and where improvements are needed. Since implementation, we have seen significant improvement in cybersecurity across the agency.

  1. What one thing about the NRC do you wish more people knew?

That we have Resident Inspectors at each of the nuclear plants. I think a lot of the public believe we regulate and inspect from a distance. I do not believe many know we have feet on the ground at the nuclear plants.

Five Questions With is an occasional series where we pose the same five questions to NRC staff.

ncsam-web_edited-1For more information on National Cyber Security Awareness Month, go here.

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