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Plenty of Progress to Report on Fukushima-related Enhancements

Scott Burnell
Public Affairs Officer

fukushimaThe NRC’s technical staff, industry executives and a public interest group will brief the Commissioners Thursday on the agency’s efforts to implement what we’ve learned from the Fukushima nuclear accident. The bottom line is the NRC is ahead of schedule on several fronts.

Some of the best news involves U.S. reactors meeting requirements from two of the NRC’s Fukushima-related Orders issued in March 2012. By the end of this spring, almost a quarter of the U.S. fleet will comply with the Mitigation Strategies and Spent Fuel Pool Instrumentation Orders. We expect more than half the fleet will meet those Orders by the end of December, which is a full year before the Orders’ deadline.

Every U.S. reactor will comply with the instrumentation requirements by the December 2016 deadline. Every reactor will also comply by that time with a major Mitigation Strategies requirement – additional, well-protected onsite portable equipment to support key safety measures if an extreme event disables a plant’s installed systems. The U.S. industry has already set up two response centers with even more equipment that can be transported to any U.S. reactor within 24 hours. By the time we say good-bye to 2016, almost every reactor will also have made all modifications needed to use those portable systems. In preparing to meet the deadlines, U.S. reactors have already enhanced their ability to keep the public safe.

About a dozen plants will have made all those modifications except changes closely related to the third Order, which requires Hardened Vents for reactors with designs similar to those at Fukushima. These vents would safely relieve pressure in an emergency and help other systems pump cooling water into the core. All the reactors subject to the Order have completed plans for the first set of vent enhancements or installation of new vents.

The NRC staff finished reviewing these plans earlier this month, ahead of schedule, and issued written evaluations to each plant. The agency is also about ready to issue guidance on how these plants can meet the second part of the Order, which involves an additional vent or other methods to protect the structure surrounding the reactor.

The staff’s presentation will also cover topics including revising the NRC’s rules in these areas, as well as the ongoing effort to re-evaluate flooding hazards for all U.S. nuclear power plants. The NRC’s regional offices will provide their perspective on the overall implementation effort’s progress.

Documenting a Sobering Trip to Fukushima

Scott Burnell
Public Affairs Officer

Reflections on FukushimaAs we mentioned on the blog last year, senior NRC leaders visited the site of the Fukushima nuclear accident and the surrounding area. Now, the agency has published a report that includes essays on what the team members learned. The report helps ensure current and future NRC staff can benefit from the team’s experience in the future.

The group included managers from the agency’s reactor oversight, research and emergency preparedness programs. They make up most of the agency’s Fukushima Steering Committee, which guides the staff’s implementation of what we learned from the accident. They also take active roles in ensuring U.S. nuclear power plants are prepared to deal with events similar to what happened at Fukushima experienced.

It’s clear from the team members’ essays that the visit affected them deeply. For example, Bill Dean (now director of the NRC’s Office of Nuclear Reactor Regulation) was Administrator of the NRC’s Region I office outside Philadelphia when he took part in the trip. “Most importantly, it enabled us to observe firsthand the far-reaching impacts of a nuclear disaster—not only its physical effects on the facility and the surrounding countryside but also its impact on a nation’s psyche and its people,” Dean writes. “What resonated with each and every one of us is that we cannot allow a Fukushima-like event to occur in the United States.”

Marc Dapas, Adminstrator of the Region IV office in Arlington, Texas, reflects on discussing the accident with plant staff at Fukushima. “Hearing these TEPCO employees describe what they faced and then seeing the actual physical configuration of equipment at the Fukushima sites left an indelible impression on me regarding the importance of being prepared for the unexpected,” Depas writes. “In that context, I considered the safety measures and enhancements that the NRC has required … The key in my view is to ensure that these safety measures are rigorously implemented and maintained.”

The team’s visit covered both the damaged Fukushima Dai-ichi plant and the nearby Fukushima Daini plant, which safely withstood the 2011 earthquake and tsunami. The visit also covered Kashiwazaki-Kariwa, a nuclear power plant on Japan’s west coast that survived a strong 2007 earthquake.

You can read the essays from Dean and the other trip participants in the report, and you watch a summary video about the trip on the NRC’s YouTube channel.

Natural Hazards Are Part of the Planning

Scott Burnell
Public Affairs Officer

 

Up to now the 2014 Atlantic hurricane season has been pretty calm, but the NRC always keeps an eye out for the strong weather-related events and other natural events the world can generate. We make sure both U.S. nuclear power plants and the agency are prepared for high winds, storm surge and a whole lot more.

Most recently, the seven reactors affected by 2012’s Superstorm Sandy remained safe. Other plants have safely withstood powerful storms, including Waterford 3 in Louisiana handling the effects of 2005’s Katrina and Turkey Point in Florida safely taking a direct hit from 1992’s Andrew.

Sandy may have left a mess in New York, but the nuclear reactors in its wake remained safe. Photo courtesy of FEMA

Sandy left a mess in New York, but the nuclear reactors in its wake remained safe. Photo courtesy of FEMA

Flooding can happen with or without storms, and U.S. plants are designed to and safely ride out significant events, such as when Fort Calhoun in Nebraska dealt with an overflowing Missouri River in 2011. Also in that year, Vermont Yankee remained safe as the Connecticut River valley suffered severe short-term floods from Hurricane Irene’s remnants.

Japan’s Fukushima Dai-ichi nuclear accident in March 2012 showed the world what flooding (in this case from a tsunami) can do to a reactor. The NRC’s learned several flooding-related lessons. from the accident. As a result of NRC direction, U.S. plants are using the latest software and technical know-how to re-analyze all flooding sources. This will help the NRC determine if the plants need to consider higher flooding water levels when establishing plans to stay safe. This effort has also examined existing flood protection and all plants have taken steps to confirm they can implement reliable flood safety plans. In the meantime, several plants have also chosen to enhance their flood protection.

An earthquake caused the tsunami that devastated Fukushima, and again U.S. plants are designed to stay safe in the face of quakes that affect their area. Virginia’s North Anna plant was hit by an August 2011 quake centered a short distance away. The earthquake was strong enough to be felt across the East Coast; it shook North Anna with a little more force than what the plant was originally designed to withstand. North Anna remained safe – multiple inspections showed the plant’s systems were undamaged. This was unsurprising, since plant systems are designed to withstand a combination of events that can exceed the forces generated by an earthquake alone.

As with flooding, the NRC has learned from Fukushima’s quake and other recent earthquakes, and we’re having every U.S. plant reanalyze earthquake hazards to see where enhancements might be needed. All the plants east of the Rockies have taken the first step in that process, and the other plants will do the same next March.

U.S. reactors are also designed for (and have safely survived) hazards such as tornadoes, droughts and other severe weather events. Even with all this preparation, Fukushima reminds us to prepare for the unexpected. The NRC’s approach here involves every U.S. reactor having additional portable systems to restore and maintain safety functions.

All of this work helps ensure the public stays safe when natural disasters strike that may impact U.S. nuclear power plants.

Fukushima Daiichi Now: Images and Perspectives

NRC officials tour one of the damaged units at the Fukushima Daiichi plant during their trip in February.
NRC officials tour one of the damaged units at the Fukushima Daiichi plant during their trip in February.
Roger Hannah
Senior Public Affairs Officer
Region II
 

In February, an NRC delegation, mostly comprised of senior managers responsible for reactor oversight, travelled to Japan to see, hear about and learn from the accident there in March 2011.

I was there to record the images and sounds of the trip – from the meetings to the tours of facilities, including the stricken Fukushima Daiichi plant, and the surrounding countryside. In interviews and conversations, I heard varied perspectives, but my focus was almost completely on people:

  • The people whose homes and businesses and schools now sit abandoned near the plant – some knowing they may never go home again.
  • The people who worked at the plant during and after the accident trying to keep the situation from being worse.
  • The people who now work at the site donning protective clothing each day as they slowly tackle the mammoth cleanup.
  • The people across Japan who continue to struggle with their view of nuclear power.

I wish we had been able to spend more time in the evacuated areas near the plant, but even the hours we were there carved indelible images in my memory. It’s interesting how seeing areas without people made me think about the missing people even more.

When it comes to nuclear safety, the most important people are those working inside or living closest to the plants. There is no stronger evidence than the images we captured during the trip.

It was difficult to distill all we saw and heard into the short video we posted on the NRC YouTube channel, but I hope we were able to show the essence of the trip…and for me, it was all about people.

 

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.

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