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Writing Rules on Lessons Learned From Fukushima

Timothy Reed
Project Manager
Office of Nuclear Reactor Regulation

The NRC is moving forward in making permanent some of the lessons we’ve learned from the Fukushima nuclear accident. The Commission has directed the staff to seek public comments on a draft proposed rule for mitigating “beyond-design-basis events,” which can be stronger than a plant’s design anticipates.

The Commission made a few changes to the proposed rule, which consolidates several of the most safety significant recommendations of the NRC’s task force report from shortly after the events at Fukushima.

One of the Commission’s changes involves Severe Accident Management Guidelines, or SAMGs, which a plant would use in responding to very unlikely accidents. The Commission directed that the plants will continue implementing those guidelines voluntarily. Each plant will document a commitment to keep their SAMGs up to date and integrate SAMGs with other emergency response guidelines.  The NRC will provide periodic oversight of SAMGs through its Reactor Oversight Process. Another Commission change to the proposed rule removes proposed design requirements for new reactor applicants. Instead, the new reactors would be subject to the same performance-based criteria that applies to the currently-licensed fleet.

The proposed rule would apply the requirements of two existing orders, Mitigation Strategies (EA-12-049) and Spent Fuel Pool Instrumentation (EA-12-051), to any operating or future U.S. nuclear power plant. The Mitigation Strategies Order ensures that if a plant loses power, it will have sufficient procedures, strategies, and equipment to indefinitely cool the reactor core and spent fuel, as well as protect the reactor’s containment. The Spent Fuel Pool Instrumentation Order requires the plants to ensure they can monitor spent fuel pool water levels. These two orders are already being implemented across the nuclear fleet.

The proposed rule addresses other task force recommendations by:

  • Establishing standards that ensure plants smoothly transition between different emergency procedures, keeping the plants’ overall strategies coherent and comprehensive;
  • Enhancing emergency response requirements so sites can address events involving more than one reactor or a reactor and spent fuel pool;
  • Requiring training, drills and exercises on the new capabilities;
  • Improving onsite and offsite communication, and
  • Ensuring sites have enough staff to address a multi-reactor event

The rule also incorporates information from the plants’ reevaluated earthquake and flooding hazards. Each plant’s mitigation strategies used to meet the rule’s requirements must remain available in the face of the reevaluated hazards.

The staff expects to provide a proposed final rule to the Commission in December 2016.  The NRC staff expects the rule, if approved, would be effective approximately two years later, with the exact date varying from plant to plant. Although that may seem far away, keep in mind much of the rule is already required by the two orders. Nearly all U.S. plants will comply with those orders by the end of 2016. Safety is being enhanced well before the final rule.

The public can comment on the draft proposed rule until Feb. 11, 2016. To view the proposed rule or submit comments, go to http://www.regulations.gov and search for Docket ID NRC-2-14-0240. You may also e-mail comments to Rulemaking.Comments@nrc.gov. The staff is also planning a public meeting during the comment period, and we’ll post the meeting notice on our public website. We look forward to hearing from you. (Just a note, comments to this blog post are not considered official NRC communication. Please use the other methods above if you wish your comments to be formally considered.)

Preparing for Subsequent License Renewal

Albert Wong
Division of License Renewal
Office of Nuclear Reactor Regulation

The NRC’s operating licenses for commercial nuclear power reactors are valid for 40 years and may be renewed for an additional 20 years at a time.  So far the agency has renewed 78 licenses and has applications for another 16 under review. We received the first license renewal application in April 1998, and we’re expecting to receive the last application for a first renewal sometime after 2020.

Today, Dominion Virginia Power announced that it expects to submit a subsequent license renewal application in 2019 – a renewal beyond the 60 years of operation from the first license and the initial renewal — for Surry Power Station.

Subsequent renewal applications will be reviewed under the same regulations (10 CFR Part 54) as the initial renewals. That means they will get similar scrutiny for both safety (focusing on how the plant operators manage the effects of aging on certain plant components) and environmental impacts. There will also be opportunities for public input and hearings.

Of course, operating plants beyond 60 years may raise different technical issues for us to address in these reviews. So we are drawing on our experience with the initial license renewals, plant operating experience, ongoing research, and expert opinions to identify strategies for dealing with the challenges of extending operation to 80 years. Two draft guidance documents will be published in December 2015 for public comment. They are “Generic Aging Lessons Learned for Subsequent License Renewal Report” and the “Standard Review Plan for Review of Subsequent License Renewal Applications for Nuclear Power Plants.”

The final guidance documents – including responses to public comments and explanations of any changes from the drafts – will be published in time to support our review of subsequent license renewal application.

Plant operators applying for subsequent license renewal will need a detailed technical basis, along with associated research and “aging management programs,” to demonstrate how they will keep their plants operating safely during the additional 20 years. The NRC staff will give these applications the same thorough reviews we give initial renewals. We expect the reviews will take about two years, though the quality of the applications could affect the schedule.

The NRC is proactively preparing for anticipated subsequent license renewal applications and stands ready to ensure the continued safety of operating plants once applications are received.



Counting the Costs on Advanced Reactor Reviews

Anna Bradford, Chief
Advanced Reactors and Policy Branch
Office of New Reactors

We’re continuing to examine topics from the recent two-day public workshop we jointly hosted with the Department of Energy regarding non-light water reactor designs. One topic getting a lot of attention is the possible costs for NRC reviews of applications for these designs.

Last month’s workshop included presentations on the NRC’s experience licensing non-light water designs, as well as discussions of proposed advanced reactor designs.

Last month’s workshop included presentations on the NRC’s experience licensing non-light water designs, as well as discussions of proposed advanced reactor designs.

For instance, some people interpreted a DOE presentation on the Next Generation Nuclear Plant project as saying it costs $800 million to receive a final certification or license from the NRC. The bulk of that $800 million, however, falls outside of NRC fees and would be made up of the designer’s costs to develop and test its design to ensure that it works as planned.

In other words, the designer does not pay the NRC $800 million to review a reactor design. Looking at recent reviews of large light-water reactors, we see designers spent approximately $50 – $75 million for NRC fees to certify their designs.

A recent Government Accountability Office assessment, “Nuclear Reactors: Status and Challenges in Development and Deployment of New Commercial Concepts” says costs can be “…up to $1 billion to $2 billion, to design and certify or license the reactor design.” A different portion of the GAO report, however, pointed out most of these costs aren’t attributable to the NRC review. The largest part of the price tag would be research, development, and design work to develop and test a new reactor design.

We can also examine information from the public workshop on design development costs versus NRC review costs for the developer of a new small modular reactor design. The company said that of approximately $300 million in design investment to date, only $4 million of that amount (or slightly more than 1 percent) is from NRC fees for several years of pre-application interactions with the agency.

Here’s something to keep in mind: NRC review costs depend on the quality and maturity of the applicant’s information. The NRC always aims to efficiently and effectively review designs. Incomplete or inadequate information will very likely increase costs, however, since the NRC will spend more time and effort getting the data necessary to determine whether the reactor could operate safely and securely.

Everyone benefits from a common understanding of NRC costs as we discuss the next generation of reactor designs. The NRC’s website has more information on how the agency is approaching advanced and small modular reactor designs.

Defining the Color of Oversight

Lara Uselding
Public Affairs Officer
Region IV

We regularly interact with various audiences from the media to the public and one question pops up often: Why does the NRC use colors to discuss issues found at a plant and what does it all mean?

PI_ROPThe quick answer is that color-coding is a lot more understandable to people outside the agency than trying to interpret a probabilistic risk calculation of core damage frequency of 10-5. (The NRC uses probabilistic risk in assessing the potential safety significance of nuclear safety issues and plant performance indicators so inspections focus on those plant activities that could have the greatest impact on safety.)

The colors we use — green, white, yellow and red — are used to prioritize the findings with greater safety significance. A more risk-significant issue is called a red finding and that will move an operating plant into our highest category for oversight followed by thousands of extra hours of inspection. An example would be a failure in a key safety-related component.

A green finding might be given when an inspector finds that one of 10 bolts on a valve is looser than the others and should be tightened. While it may not sound like a big deal, the NRC has high standards for safety and a low threshold for issues.

White and yellow findings are medium risk. In 2015, 428 green findings, 13 white findings and two yellow findings were issued. An example of a yellow finding was one given for seals that were not adequate to protect a room housing electrical equipment from flooding. An example of a white finding was for improper maintenance that resulted in a failed emergency diesel generator fan belt.

Who decides the colors? Initially, the inspector determines the safety significance and assigns a tentative color. A green finding may not require additional analysis. But with the higher colors, there is a detailed assessment that could involve NRC risk experts and, in some cases, a discussion with the plant operator to obtain more information.

The final outcome of the review — evaluating whether the finding is green, white, yellow, or red — will be used to determine what further NRC action may be called for, such as moving a plant up in the columns that comprise the NRC’s performance “Action Matrix.” When poor performance lands a plant in one of these higher oversight columns with increased inspections, it takes a lot of hard work to return the plant to a better standing.

Dry Cask 101: Storage and Transport – The Right Materials for the Job

John Wise
Materials Engineer

CASK_101finalMaterials – the stuff of which everything is made. You might not give much thought to the materials around you: the metal in the door of your car, the plastic used in airplane windows, or the steel from which elevator cables are made. Yet, in each of these cases, the selection of appropriate materials is critical to our safety.

Systems that transport and store spent nuclear fuel and other radioactive substances are made of a variety of materials. All of them are reviewed to confirm that those systems can protect the public and environment from the effects of radiation. The NRC does not dictate what materials are used. Rather, the NRC evaluates the choice of materials proposed by applicants that want NRC approval of systems to transport or store radioactive substances.  We typically refer to these substances as radioactive materials, but that might make this discussion much too confusing.

What makes a material “appropriate” to transport and store radioactive substances depends on a number of factors.

First, materials must be adequate for the job. In other words, the mechanical and physical properties of the materials have to meet certain requirements. For example, the steel chosen for a transportation canister has to withstand possible impacts in a transport accident.  Neutron-absorber materials need to block the movement of neutrons to control nuclear reactions in spent nuclear fuel.

Next, when making complex metal system, parts often are fused together by partially melting, or welding, them in a way that ensures that the joints themselves are adequate for the job. It may not be obvious, but during the welding process, the welder is creating a new material at the joint with its own unique properties.  That’s why the NRC looks at how this is done, including the selection of weld filler metals, how heat is controlled to ensure good welds, and the use of examinations and testing to verify that no defects are present.

Horizontal storage systems under construction.

Horizontal storage systems under construction.

Finally, the NRC considers how materials degrade over time. In other words, we must take into account a material’s chemical properties – how it reacts with its environment. We’re all familiar with how iron rusts when it gets wet or how old elastic materials (e.g., rubber bands) become brittle. Often such degradation is not important. But sometimes it can cause concern. Thus, materials must be selected based on their present condition and their projected condition throughout their lifetimes.

Best practices for appropriately selecting materials and the processes used to join them often can be found in consensus codes and standards. These guidelines are typically developed over many years of experience and through industry-wide and government agreement.  But such guidelines may not cover all aspects of material selection. So we also rely on both historical operating experience and the latest materials testing data.

The NRC has a team of materials experts that reviews every application we receive for approval of spent fuel storage and transportation systems. These experts must be satisfied that every material and the processes used to join them are up to the job. The materials review is one part of a comprehensive review the NRC does on every application. We will focus on other parts of our reviews in upcoming blog posts.


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