TSUNAMI SAFETY OF NPPS SMiRT 22 in the United States August 2013 - - PowerPoint PPT Presentation

DEVELOPMENT OF REGULATORY REGULATORY DEVELOPMENTS FOR TSUNAMI SAFETY OF NPPS in the United States

Tsunami- Technology and Guideline Development SMiRT 22 August 2013

¡ Tsunami regulations and regulatory guidance ¡ Objective and outcomes of the NRC tsunami research program ¡ Post-fukushima guidance in support of the 50.54(f) letter ¡ New PFHA activities (Chronological order)

OVERVIEW

US COASTAL NPPS

Ø 2 Pacific Coast Sites

• 4 units
• 2 units closing

Ø 2 Gulf Coast Sites

• 3 units

Ø 11 Atlantic Coast Sites

• 18 units

¡ US documents addressing hazard assessment, design, and risk assessment are available ¡ Tsunami hazard assessments are site-specific. There is no minimum value. A hierarchical approach is used ¡ Generally (but not always) the flooding from hurricane storm surge exceeds the flooding expected from a tsunami for plants on the Atlantic and Gulf Coast ¡ The PRA Standard (ASME/ANS-Ra-Sa2009) addresses technical requirements for both seismic events and tsunamis (tsunami hazard under the technical requirements for external flooding analysis)

HAZARD ASSESSMENT AND DESIGN FOR NPPS

¡ General Design Criterion 2 (GDC 2), 10CFR50, requires, in part, that structures, systems, and components important to safety be designed to withstand the effects of natural phenomena such as floods, tsunami, and seiches without loss of capability to perform their safety functions. ¡ 10 CFR 100.23, requires, in part, that the size

• f seismically induced floods and water waves

that could affect a site from either locally or distantly generated seismic activity must be determined.

CODE REQUIREMENTS FOR HAZARD ASSESSMENT FOR NPPS

§ RG 1.59 (1977), “Design Basis Floods for Nuclear Power Plants noted the need for tsunami assessments” § RG 1.102 (1976) “Flood Protection for Nuclear Power Plants”

HISTORY OF THE TSUNAMI HAZARD GUIDANCE FOR NPPS

2004 EARTHQUAKE & TSUNAMI

• NRC initiated an Tsunami Technical Advisory

Group to determine need for new tsunami hazard assessment guidance.

• A tsunami research program was developed in

2005 in response to a User Need Research Request issued to the Office of Research from the licensing offices for new and operating reactors.

NRC EARLY TSUNAMI ASSESSMENT ACTIVITIES

• Provide Tsunamigenic Source Characterization for all key

sources

• Near-field and Far-field sources
• Seismic and Landslide-based sources
• Deterministic and probabilistic parameters include source

geometry, orientation, size, return period, etc.

• Provide approaches for initiation, propagation, and

inundation numerical modeling and related assessments

• Provide technical support for deterministic & probabilistic

hazard assessments for proposed and existing plants

• Develop the technical basis for hazard assessment guidance

including assessment approaches & modeling tools

• Issue new Regulatory Guidance

OBJECTIVE OF THE NRC TSUNAMI RESEARCH PROGRAM

¡ In response to the Indian Ocean Tsunami, the NRC supported work to develop three new reports.

§ NOAA Technical Memorandum OAR PMEL-136 (2007), “Scientific and Technical Issues in Tsunami Hazard Assessment of Nuclear Power Plant Sites” § NUREG/CR-6966 (2008), “Tsunami Hazard Assessment Nuclear Power Plants Sites in the US” by PNNL § NOAA also produced PMEL-135 (2007) “Standards, criteria, and procedures for NOAA evaluation of tsunami numerical models”

TSUNAMI HAZARD GUIDANCE FOR NPPS

¡ NUREG-0800 (2007), “Standard Review Plan for the Review of Safety Analysis Reports for Nuclear Power Plants (LWR [light-water reactor] Edition)”, updated in preparation for new NPP applications ¡ Section 2.4.6 is “Probable Maximum Tsunami Flooding”

TSUNAMI HAZARD GUIDANCE FOR NPPS

¡ USGS (2007) Report on all potentially tsunamigenic sources in Atlantic & Gulf coasts (both seismogenic & landslide) ¡ Updated (2008) USGS Report, “Evaluation

• f Tsunami Sources with the Potential to

Impact the U.S. Atlantic and Gulf Coasts: an updated Report to the Nuclear Regulatory commission” used by licensees and NRC staff reviewing new NPP applications ¡ Results also published in a special issue

• f Marine Geology

TSUNAMI HAZARD GUIDANCE & RESEARCH RESULTS

¡ Significant increase in understanding of landslide distribution & mechanisms on US Atlantic & Gulf coasts ¡ Increase in understanding of important parameters of characterization and modeling

TSUNAMI HAZARD GUIDANCE & RESEARCH RESULTS

¡ Example of NRC use of USGS landslide data for licensing review. Modeling performed by Prof. Lynett of USC in conjunction with USGS.

TSUNAMI HAZARD GUIDANCE & RESEARCH RESULTS

¡ NOAA coupled the iSale impact code with the global model and the source parameters in the USGS Report to assess hazard on the US Atlantic coast from a Canary Islands flank failure and other major Atlantic sources ¡ Results were provided in a report to the NRC and were published by NOAA

TSUNAMI HAZARD RESEARCH RESULTS

¡ NRC staff also contributed to IAEA 2011 guidance for hydrological hazards ¡ Appendix II “Current Practice in Some States,” also included information on the practice in the US and Japan

HAZARD GUIDANCE FOR NPPS

PROBABILISTIC TSUNAMI HAZARD ASSESSMENT RESEARCH

¡ NRC continues to work on PTHA (&PFHA) methods ¡ NRC/USGS Workshop on Landslide Tsunami Probability held 2011 ¡ Tsunami session in 2013 NRC- sponsored Probabilistic Flooding Hazard Assessment workshop ¡ Efforts to develop guidance/ training on applying the SSHAC guidelines (NUREG 2117and NUREG/CR-6372) to PFHA

2011 EARTHQUAKE & TSUNAMI

¡ In support of the 50.54(f) Request for Information responses (for NTTF Recommendation 2.1)

§ JLD-ISG-2012-06 (2012), “Guidance for Performing a Tsunami, Surge, or Seiche Hazard Assessment.” (Tsunami assessment guidance is provided, but limited.) § JLD-ISG-2012-05 (2012), “Guidance for Performing the Integrated Assessment for External Flooding”

NTTF RECOMMENDATION 2.1 GUIDANCE DOCUMENTS

¡ Continued development of technical basis for regulatory guidance ¡ Development of new NRC regulatory guidance for tsunami hazard assessment planned ¡ Development of probabilistic methods for PTHA (with integration into PFHA) ¡ Support of work at IAEA on Tsunami PSA ¡ Post-Fukushima 50.54(f) activities in flooding reevaluation for operating NPPs ¡ New reactor licensing

ONGOING TSUNAMI ACTIVITIES

THANK YOU FOR YOUR KIND ATTENTION