U.S. NRC Blog

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Fukushima Lessons: Updating Earthquake Hazards at U.S. Nuclear Plants

Scott Burnell
Public Affairs Officer

The NRC is examining new earthquake-related information from U.S. nuclear power plants, and we’re making that information available over the next week or so. We’d like to summarize how we got here and what the next steps are.

seismicgraphicNuclear power plant designs set a basic standard for reactors to completely and safely shut down after an earthquake, based on site-specific information. Plant construction methods and other design factors add to a reactor’s capacity to safely withstand stronger motions than what the basic design describes.

The end of March marked an important milestone for our post-Fukushima activities. We received 60 reports from central and eastern U.S. nuclear power facilities updating the seismic hazard at their individual reactors. The NRC staff is making these reports available through its normal process. The NRC will post each plant’s report on the agency website’s Japan Lessons-Learned Activities page.

We will require the same updates of the three western power plants (Palo Verde in Arizona, Columbia Generating Station in Washington, and Diablo Canyon in California), but delayed by one year because of the more complex geology in that region of the country. Each western plant is individually looking at the seismic sources and local ground motion characteristics that could affect it. This Senior Seismic Hazard Analysis Committee process will inform the overall seismic hazard reassessment that the western plants are completing.

Our staff will spend the next month going over the submissions carefully, checking for errors, before confirming which plants will be required to do more extensive analysis of their ability to respond safely to a significant earthquake event.

These reports mark the first step in a comprehensive process to keep safety at U.S. plants up-to-date with the latest understanding from the earth sciences on the processes that create earthquakes in the U.S.  In 2012, the Department of Energy, Electric Power Research Institute and the NRC joined forces to update the “seismic source model” for the central and eastern U.S. This was based on a new understanding of what creates earthquakes on the North American tectonic plate, with a focus on the New Madrid fault zone near St. Louis, the Charleston fault zone near Charleston, S.C., and other updated information.

The data on seismic sources will be used in conjunction with a ground motion model for the central and eastern U.S. as well as data from individual plants on the localized geology, topography, soil cover, and other data to create a picture of the “ground motion response spectra” for each plant. This new ground motion response spectrum at each plant will be compared with that developed in the past to see if the new data suggests the plant could see higher ground motions than previously thought. If that is the case, the plant will be considered to have “screened in” to further detailed seismic hazard analysis.

Those plants that “screen in” will be required to do a seismic “probabilistic risk assessment” or a seismic “margin analysis” to evaluate in detail how the existing plant structures and systems would respond to the shaking from the range of earthquakes that could affect the plant based on our current understanding of seismic sources. This assessment is extensive, involving experts from a variety of fields, and will require at least 3 years to complete. Once these assessments are complete, the NRC will decide if significant upgrades to plant equipment, systems, and structures are required.

In the meantime, to ensure that the plant is safe, the NRC requires that by the end 2014, plants have reported the interim actions they will take to ensure the safety of the plants before the assessment is complete. Such measures could include re-enforcing existing safety-significant equipment or adding equipment.

It’s important to remember that significant earthquakes at central and eastern U.S. plants are unlikely. But it is our job to ensure that these plants are ready for all that nature might throw at them. And it is our job to keep up with the changes in the science to ensure that plants are as safe as they can be.

Addressing the Unpredictable Through Mitigation Strategies

Lauren Gibson
Project Manager
Japan Lessons-Learned Directorate

The Fukushima accident reminded us how important prior planning is when it comes to safely handling extreme events at a nuclear reactor. We continue to conclude U.S. plants can survive many scenarios, such as loss of offsite power or flooding. After Fukushima, however, we’re requiring plants to have strategies for dealing with the long-term loss of normal safety systems.  Instead of figuring out which events might happen, we’re focusing on significantly improving the plants’ flexibility and diversity in responding to extreme natural phenomena (such as severe flooding, earthquakes, extreme temperatures, etc.).

mitigation_strategies_infographic_r4The plants’ strategies must protect or restore key safety functions indefinitely in the case of an accident. The strategies focus on keeping the core cool, preserving the containment’s barrier that prevents or controls radiation releases, and cooling the spent fuel pool. Plants with more than one reactor must be able to do this for every reactor on site at the same time.

Ideally, plants would have everything for their strategies on site. The strategies must protect the plant indefinitely, however, so plants may need to bring in additional equipment or resources.  The order reflects this by having three phases with different requirements.

The first phase begins with the accident or event.  At this point, the plants will use installed equipment, such as steam-driven pumps or battery-powered systems, to protect or restore safety functions. The plants must be able to shift to the second phase before the installed equipment is exhausted.

The strategies’ second phase uses portable equipment that’s stored onsite, such as additional pumps or generators. This equipment is stored near the reactors and reasonably protected from severe weather or earthquakes. The phase two resources are brought to the reactors and connected to maintain the safety functions. During this phase, plants would also be able to transfer fuel from onsite tanks to the places were it’s needed to run generators and other equipment. Plants have to ensure the third phase can take over before the portable equipment runs out of supplies.

The final phase starts when outside help arrives. The nuclear energy industry is setting up two response centers to provide additional equipment and other resources to any U.S. reactor within 24 hours. One center is in Memphis, Tenn., and the other is in Phoenix, Ariz.

The plants have all submitted a plan for what they intend to do and use in each of these phases. The plans must also explain how the plants will have everything in place by the end of 2016.  We’ve been reviewing those plans and we’re at the point of issuing interim staff evaluations, which let the licensee know whether we think they are on the right track. The NRC will inspect the plants throughout this process to ensure the strategies will get the job done. Our website’s Japan Lessons Learned section has more information about the mitigation strategy requirements and related guidance.

Note: The graphic is now available on our Flickr site.

The NRC Supports Local Science with A Special Student Award

Jenny Tobin
Project Manager
Office of Nuclear Reactor Regulations

The Montgomery County (Md.) Science fair, aka “ScienceMontgomery,” is not your average science fair. Many of the students living in the communities around the NRC headquarters have access to advanced science curricula and research opportunities, and there is a large pool of high-tech, biomedical, and research institutes that set the bar high for hands-on learning.

For me, who grew up in a very small Midwest farming community, serving as a judge for a special NRC award is always an eye-opening experience.

Jenny Tobin reviews Montgomery County, Md., science projects for a special NRC award.

Jenny Tobin reviews Montgomery County, Md., science projects for a special NRC award.

I was in good company with a 14-person volunteer team of NRC employees who got to evaluate more than 300 science projects from local middle schools and high schools. I was on the team that reviewed the high school projects and we picked the top three for NRC Community Awards that demonstrated achievement and application to the NRC mission, goals and responsibilities.

What I find most interesting, year after year, is watching, listening and seeing the current trends in topics the students choose as their science project.

A science project can be an experiment, a demonstration, a research effort, a collection of scientific items or display of scientific apparatus presented for viewing. This year there was a huge surge in cyber security, computer modeling and analyses projects throughout the fair.

In the high school completion judges must listen to the student’s presentation and their responses to questions asked. You can tell immediately which students know their topics and which ones have had too much adult or parental support.

What stands out when you speak to students can easily be summed up in their ingenuity of their project design, subject knowledge and passion for discovery solutions. I found these in the 2014 NRC award winners.

I particularly find amazing how the students re-engineer and recycle materials, and create new working designs. In the case of the first place project “Replacing Modern Sprinkler Systems with Infrared Detection to Locate and Extinguish Fires,” it was cool how they took motherboards, rubber bands and other common household items to create a working product that used infrared sensor technology to detect the hot spots of a fire and direct water to this location. For the NRC, fire protection and fire code continues to be a major spotlight issue in nuclear power plants and facilities. 

When I listened to the student whose project, “Saturated Nuclear Matter in the Large Nc and Heavy Quark Limits of Quantum Chromodynamics,” his ownership or mastery of the subject and presentation was so amazing that it made me flash back to my own quantum physics professors in college. This high-schooler was so savvy and professional. Basically his project worked through mathematical proofs, from first principles, on fundamental properties of quantum chromodynamics.   

NRC Deputy Executive Director Michael Weber (left) presents special awards for projects that relate to the agency's work. Also in the picture (left to right) students Richard Wang, Kevin Chen, Andrew Komo, Noah Kim, George Klees and the NRC’s Kreslyon Fleming.

NRC Deputy Executive Director Michael Weber (left) presents special awards for projects that relate to the agency’s work. Also in the picture (left to right) students Richard Wang, Kevin Chen, Andrew Komo, Noah Kim, George Klees and the NRC’s Kreslyon Fleming.

Novel solutions to real world problems such as “Finding Ways to Reduce Rush Hour Commute Times Using Computer Simulations” were another common theme at the science fair. This student programmed a simulation for a certain section of highway to evaluate potential solutions (such as adding exits, increasing the speed limit, adding a lane, etc.) to determine the best method to reduce traffic delays. He used data from the Department of Transportation to construct a true-to-life model of the situation. I could use less traffic to and from work!

In the end, learning about science is at the heart of a science fair; and anything I can do to fuel this passion is reward enough. By the way, the NRC supports this event because it is a way to give back to the community, engage students with an interest in STEM careers and – possibly – as a future recruitment tool. Winners receive an award certificate, a chance to present their projects to NRC staff and a NRC logo merchandise gift certificate.

Nine students were selected for the NRC Community Award that demonstrated achievement and application to the NRC mission, goals and responsibilities.

Middle School (Junior) Division:

1st Place: Raspberry Pi Controlled Robots — Student: Kevin Chen; Roberto Clemente Middle School

2nd Place: Securing Computer Networks — Students: George Klees and Theo Tosini; Takoma Park Middle School

3rd Place: The Efficiency of Data Encryption Methods — Student(s): Andrew Komo and Noah Kim; Takoma Park Middle School

High School (Senior) Division:

1st Place: Replacing Modern Sprinkler Systems with Infrared Detection to Locate and Extinguish Fires — Students: Ishan Mundra and Karan Chawla; Poolesville High School

2nd Place: Saturated Nuclear Matter in the Large Nc and Heavy Quark Limits of Quantum Chromodynamics — Student: Ishaun Datta; Montgomery Blair High School

3rd Place: Finding Ways to Reduce Rush Hour Commute Times Using Computer Simulations — Student: Richard Wang; Poolesville High School

The Three Mile Island Nuclear Plant – An Update on the 35th Anniversary

Neil Sheehan
Public Affairs Officer
Region I
The Three Mile Island Unit 2 Control Room bustles during the crisis in 1979. For more historical information, click on the photo to go to the NRC YouTube video about the accident.

The Three Mile Island Unit 2 Control Room bustles during the crisis in 1979. For more historical information, click on the photo to go to the NRC YouTube video about the accident.

Today marks 35 years since the accident at the Three Mile Island 2 nuclear power plant. As is the case every year, it represents another opportunity to reflect on the most significant nuclear power plant accident to ever occur in the U.S.

Perhaps less well known to the average citizen is where things stand in terms of the Middletown, Pa., site all these years later.

GPU Nuclear, which owned the plant at the time of the accident, removed the damaged fuel from the reactor and decontaminated the plant in ensuing years. Once the plant was placed in a safe, stable condition, it transitioned to what is known as “post-defueled monitored storage” — a change that was formally approved by the NRC in 1993.

Last year, the current owner, FirstEnergy, submitted a roadmap to the agency on its plans for eventual dismantling the plant. Those details were contained in a document called a Post-Shutdown Decommissioning Activities Report, or PSDAR.

In short, the plant will remain in storage until its neighboring reactor, Three Mile Island 1, permanently ceases operations, something currently expected to happen in 2034. Once that happens, decommissioning work on both units will be undertaken, but those efforts are projected to take many years.

NRC regulations allow up to 60 years for the completion of decommissioning activities for U.S. nuclear power plants.

A view of the TMI-2 control room, last year, with two NRC inspectors.

A view of the TMI-2 control room, last year, with two NRC inspectors.

Meanwhile, the NRC will continue to inspect TMI-2 at regular intervals. The focus of those reviews includes maintenance of the structures, management oversight, fire protection and plant support activities. The results of those inspections can be found in the NRC’s electronic documents system.

While another anniversary has arrived for TMI, the work on keeping close watch on the plant goes on, and will continue for many years to come.

The NRC Wants to Put the “U” in Strategic Plan

Francine Goldberg
Senior Advisor for Performance Management


Well, we do realize there is no “u” in “strategic plan,” but the NRC is drafting its 2014-2018 road map and we want your input before we finalize it.

Picture1The plan is updated every four years and is used to guide our work. You may not be aware that all of NRC’s business lines (operating reactors, new reactors, fuel facilities, nuclear materials, etc.) link their annual plans to the strategic plan and all our senior executive performance plans are linked to it as well.

If you’re familiar with our previous Strategic Plan, you’ll notice our mission and strategic goals remain basically unchanged, but the new plan does contain some new components. For example, a vision statement has been added to emphasize the importance, not only of what we achieve, but of how we regulate And there are now three strategic objectives, one for safety and two for security.

Each objective has associated strategies and key activities that will be used to achieve them. For example, this is one of the strategies for the safety objective along with three key activities:

Ensure the NRC’s readiness to respond to incidents and emergencies involving NRC-licensed facilities and radioactive materials, and other events of domestic and international interest.

·        Use operational experience and lessons learned from emergency-preparedness exercises to inform the regulatory activities.

·        Coordinate with federal, state, local, and tribal partners to strengthen national readiness and response capabilities.

·        Employ outreach before, during, and after emergency-preparedness exercises, and increase collaboration and sharing of best practices and lessons learned after emergency-preparedness exercises and incidents.

The goal of the comment period is to take advantage of the collective knowledge of the public – there is a “u” in public, after all — to make sure our plan is as good as it can be.

Picture1Why should you take the time to comment? Well, perhaps you are aware of a key external factor that we have missed that could affect the strategies and activities we have planned. Or maybe you have ideas for additional strategies or activities we need to focus on to achieve one of our objectives. This is your opportunity to weigh in and tell us if we are addressing the issues of importance to you. 

All comments will be reviewed and incorporated, as appropriate, into a revised plan. The disposition of substantive comments will be included in a Commission paper transmitting the resulting plan to the Commission for their final review and approval. 

Please submit your comments online through the federal government’s rulemaking website, www.regulations.gov using Docket ID NRC-2013-0230; or by mail to Cindy Bladey, Chief, Rules, Announcements, and Directives Branch, Office of Administration, Mail Stop:  3WFN-06-44M, U.S. Nuclear Regulatory Commission, Washington, DC 20555-0001. The comment period is coming quickly. It closes on 04/04/2014. Comments on this blog post cannot be considered, so please use the official channels. More information is also available in the Federal Register Notice.

We look forward to hearing from you soon.


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