ML12340A232
| ML12340A232 | |
| Person / Time | |
|---|---|
| Site: | Sequoyah  |
| Issue date: | 12/04/2012 |
| From: | Office of Nuclear Security and Incident Response |
| To: | |
| Kahler, Carolyn NSIR/DPR/ORLOB 415-0705 | |
| References | |
| NUREG/CR-7154 | |
| Download: ML12340A232 (3) | |
Text
Message Plan NUREG/CR-7154, Risk Informing Emergency Preparedness Oversight:
Evaluation of Emergency Action Levels -
A Pilot Study of Peach Bottom, Surry and Sequoyah New study explores using risk related information to potentially enhance NRC oversight of emergency preparedness.
The staff initiated a study focusing on emergency action levels (EALs) at three nuclear power plants. The three plants were as follows: Peach Bottom, a typical boiling water reactor 4 design with a Mark I containment; Surry, a three-loop Westinghouse pressurized water reactor design with a high-head safety injection system and large dry containment; and Sequoyah, a Westinghouse pressurized water reactor with an ice condenser containment. The objective of this study was to use probabilistic risk assessment (PRA) to explore the consistency of EAL schemes.
This study evaluated the risk implications of selected EALs using plant-specific PRA models and generated the results in the form of a surrogate risk metric: conditional core damage probability (CCDP).
The pilot study evaluated EALs for plant conditions related to equipment malfunction. The study was limited by the capability of the PRA tools used. For example EALs related to natural hazards could not be evaluated in this study. Prior to this study, there had never been a PRA study to evaluate EALs as applied to emergency classifications.
The study determined the following:
In general, increasing emergency classification levels indicated a higher risk according to the risk metric.
There were some inconsistencies in the emergency ranking of some EALs.
The study used the CCDP values to determine the consistency of EALs within a given classification; however, it was not intended to provide absolute CCDP values for the various EALs or to identify absolute values for emergency classifications. Rather the CCDP values were used in a relative sense to explore the consistency of EALs within an emergency classification.
Although the study suggested improvements to the EAL schemes, it concluded that the current EALs are sufficient in terms of safety standards. This study was part of a broader effort to look at ways to enhance NRC oversight of emergency preparedness at nuclear plants through the use of risk related information. It was expected that the study could identify whether any EALs were outliers in terms of risk and any potential gaps in EALs.
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How to Access This study is available online in NRCs document system, ADAMS http://wba.nrc.gov:8080/wba/, under the following accession number: ____.
Outreach Planning Audience Internal Stakeholders Commission Office of the Executive Director of Operations Office of Nuclear Security and Incident Response Office of General Counsel Office of Congressional Affairs Office of Public Affairs Regional State Liaison Officers and EP Inspectors Office of Federal and State Materials and Environmental Management Programs Office of Nuclear Regulatory Research Office of Nuclear Reactor Regulation, specifically Project Managers for Peach Bottom, Surry, and Sequoyah sites - who are requested to notify respective licensees External Stakeholders State and local Emergency Management Agencies Federal Emergency Management Agency/Department of Homeland Security Nuclear Power Reactor Licensees Nuclear Energy Institute Conference of Radiation Control Program Directors Federal Radiological Program Coordination Council Communication Tools Emergency Preparedness & Response News Email to Stakeholders (by HQ and RSLOs) o Internal: to internal newsletter distribution list and individuals specified, requesting that they share information as appropriate o External: to external newsletter distribution list by HQ, to states and locals by RSLOs NRC Blog (OPA discretion)
Press Release (OPA discretion)
Frequently Asked Questions Are the current EALs correct?
A: The current EALs are adequate; however the study has identified enhancements.
How does this study impact our current EALs?
A: EAL guidance is in revision currently and insights from the study have been incorporated.
How were the three sites used in the study chosen?
A: These sites were chosen because they are representative of important reactor types in the U.S.
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What prompted this study to take place?
A: From time to time, the NRC conducts applied research to identify methods to risk inform regulations and regulatory guidance.
Is there a problem with how we currently classify emergencies?
A: The current classification scheme and EALs approved for every nuclear plant are adequate.
However, the study identified enhancements that may be considered by management.
What is the possible outcome of the study - new regulations?
A: The study will inform NRC regulatory guidance for EALs are nuclear power plants.
Will similar studies be done at all of the operating nuclear reactors?
A: There are no current plans to expand the study, although that may be considered by management and is dependent upon resource availability.
Will it be standard practice to complete studies like this prior to any new reactors being licensed?
A: No, this is applied research and is not performed as a standard practice. EALs for new reactor designs are being developed by industry for NRC review. In the future additional studies may be performed when there is a need.
The study mentions there is no existing EAL that describes the condition of an immediate loss of AC and DC. Isnt this what happened at Fukushima?
A: Yes. The current EAL guidance is in revision and this EAL is being added.
Will there be an EAL study developed that includes a condition where there is a total loss of AC and DC?
A: This study does include analysis of that scenario.
Will any of the results of the Japan short- or long-term review affect this ongoing work? A: The groups working on this issue may review the study for applicability, but there are no formal plans to incorporate the conclusions of the study with that effort.
The article mentions current EP regulations were developed back in 1980. Is this the first time a study of this nature has taken place, and if so, why did it take so long to initiate?
A: There have been many enhancements to the EAL scheme since the original development.
However, this is the first time probabilistic risk assessment tools have been used to analyze EALs.
How soon will the next steps begin to take place?
A: They already have with the inclusion of the immediate loss of AC and DC EAL in the next revision of the EAL guidance.
Will there be changes/adjustments made to the current EALs?
A: The NRC will issue guidance for the use of the new EAL guidance when it is issued.
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