ML15335A050
| ML15335A050 | |
| Person / Time | |
|---|---|
| Site: | Waterford  |
| Issue date: | 12/15/2015 |
| From: | Frankie Vega Japan Lessons-Learned Division |
| To: | Entergy Operations |
| Vega, Frankie NRR/JLD 415-1617 | |
| References | |
| TAC MF3712 | |
| Download: ML15335A050 (20) | |
Text
UNITED STATES NUCLEAR REGULATORY COMMISSION WASHINGTON, D.C. 20555-0001 December 15, 2015 Site Vice President Entergy Operations, Inc.
Waterford Steam Electric Station, Unit 3 17265 River Road Killona, LA 70057-3093
SUBJECT:
WATERFORD STEAM ELECTRIC STATION, UNIT 3 - STAFF ASSESSMENT OF INFORMATION PROVIDED PURSUANT TO TITLE 10 OF THE CODE OF FEDERAL REGULATIONS PART 50, SECTION 50.54(f), SEISMIC HAZARD REEVALUATIONS FOR RECOMMENDATION 2.1 OF THE NEAR-TERM TASK FORCE REVIEW OF INSIGHTS FROM THE FUKUSHIMA DAl-ICHI ACCIDENT (TAC NO. MF3712)
Dear Sir or Madam:
On March 12. 2012, the U.S. Nuclear Regulatory Commission (NRC) issued a request for information pursuant to Title 10 of the Code of Federal Regulations, Part 50, Section 50.54(f)
(hereafter referred to as the 50.54(f) letter). The purpose of that request was to gather information concerning, in part, seismic hazards at each operating reactor site and to enable the NRC staff, using present-day NRC requirements and guidance, to determine whether licenses should be modified, suspended, or revoked.
By letter dated March 27, 2014, Entergy Operations, Inc (Entergy, the licensee), responded to this request for Waterford Steam Electric Station, Unit 3 (Waterford).
The NRC staff has reviewed the information provided related to the reevaluated seismic hazard for Waterford and, as documented in the enclosed staff assessment, determined that you provided sufficient information in response to Requested Information Items (1) - (3), (5) - (9) and the comparison portion to Item (4), identified in Enclosure 1 of the 50.54(f) letter. Further, the NRC staff concludes that the licensee's reevaluated seismic hazard is suitable for other actions associated with Near-Term Task Force Recommendation 2.1, "Seismic".
Contigent upon the NRC's review and acceptance of Entergy's high frequency confirmation (Item 4) for Waterford, the Seismic Hazard Evaluation identified in Enclosure 1 of the 50.54(f) letter will be completed.
If you have any questions, please contact me at (301) 415-1617 or at Frankie.Vega@nrc.gov.
Frankie Vega, Project Manager Hazards Management Branch Japan Lessons-Learned Division Office of Nuclear Reactor Regulation Docket No. 50-382
Enclosure:
Staff Assessment of Seismic Hazard Evaluation and Screening Report cc w/encl: Distribution via Listserv
STAFF ASSESSMENT BY THE OFFICE OF NUCLEAR REACTOR REGULATION RELATED TO SEISMIC HAZARD AND SCREENING REPORT WATERFORD STEAM ELECTRIC STATION. UNIT 3 DOCKET NO. 50-382
1.0 INTRODUCTION
By letter dated March 12, 2012 (NRC, 2012a), the U.S. Nuclear Regulatory Commission (NRC or Commission) issued a request for information to all power reactor licensees and holders of construction permits in active or deferred status, pursuant to Title 1O of the Code of Federal Regulations (1 O CFR), Section 50.54(f) "Conditions of license" (hereafter referred to as the "50.54(f) letter). The request and other regulatory actions were issued in connection w!th implementing lessons-learned from the 2011 accident at the Fukushima Dai-ichi nuclear power plant, as documented in the "Near-Term Task Force Review of Insights from the Fukushima -
Dai-ichi Accident" (NRC, 2011b). 1 In particular, the NRC Near-Term Task Force (NTTF)
Recommendation 2.1, and subsequent Staff Requirements Memoranda (SRM) associated with Commission Papers SECY-11-0124 (NRC, 2011c) and SECY-11-0137 (NRC, 2011d),
instructed the NRC staff to issue requests for information to licensees pursuant to 10 CFR 50.54(f). to the 50.54(f) letter requests that addressees perform a reevaluation of the seismic hazards at their site(s) using present-day NRC requirements and guidance to develop a ground motion response spectrum (GMRS).
The required response section of Enclosure 1 requests that each addressee provide the following information:
(1) Site-specific hazard curves (common fractiles and mean) over a range of spectral frequencies and annual exceedance frequencies, (2) Site-specific, performance-based GMRS developed from the new site-specific seismic hazard curves at the control point elevation, (3) Safe Shutdown Earthquake (SSE) ground motion values including specification of the control point elevation, (4) Comparison of the GMRS and SSE. A high frequency (HF) evaluation (if necessary),
1 Issued as an enclosure to Commission Paper SECY-11-0093 (NRC, 2011a).
Enclosure
(5) Additional information such as insights from NTTF Recommendation 2.3 walkdown and estimates of plant seismic capacity developed from previous risk assessments to inform NRC screening and prioritization, (6) Interim evaluation and actions taken or planned to address the higher seismic hazard relative to the design basis, as appropriate, prior to completion of the risk evaluation (if necessary),
(7) Statement if a seismic risk evaluation is necessary, (8) Seismic risk evaluation (if necessary), and (9) Spent fuel pool (SFP) evaluation (if necessary).
Present-day NRC requirements and guidance with respect to characterizing seismic hazards use a probabilistic approach in order to develop a risk-informed performance-based GMRS for the site. Regulatory Guide (RG) 1.208, A Performance-based Approach to Define the Site- Specific Earthquake Ground Motion (NRC, 2007), describes this approach. As described in the 50.54(f) letter, if the reevaluated seismic hazard, as characterized by the GMRS, is not bounded by the current plant design-basis SSE, further seismic risk evaluation of the plant is merited.
By letter dated November 27, 2012 (Keithline, 2012), the Nuclear Energy Institute (NEI) submitted Electric Power Research Institute (EPRI) report "Seismic Evaluation Guidance:
Screening, Prioritization, and Implementation Details (SPID) for the Resolution of Fukushima Near-Term Task Force Recommendation 2.1 Seismic" (EPRI, 2012), hereafter called the SPID.
The SPID supplements the 50.54(f) letter with guidance necessary to perform seismic reevaluations and report the results to NRC in a manner that will address the Requested Information Items in Enclosure 1 of the 50.54(f) letter. By letter dated February 15, 2013 (NRC, 2013b), the staff endorsed the SPID.
The required response section of Enclosure 1 to the 50.54(f) letter specifies that Central and Eastern United States (CEUS) licensees provide their Seismic Hazard and Screening Report (SHSR) by 1.5 years after issuance of the 50.54(f) letter. However, in order to complete its update of the EPRI seismic ground motion models (GMM) for the CEUS (EPRI, 2013), industry proposed a six-month extension to March 31, 2014, for submitting the SHSR. Industry also proposed that licensees perform an expedited assessment, referred to as the Augmented Approach, for addressing the requested interim evaluation (Item 6 above), which would use a simplified assessment to demonstrate that certain key pieces of plant equipment for core cooling and containment functions, given a loss of all alternating current power, would be able to withstand a seismic hazard up to two times the design-basis. Attachment 2 to the April 9, 2013, letter (Pietrangelo, 2013) provides a revised schedule for plants needing to perform (1) the Augmented Approach by implementing the Expedited Seismic Evaluation Process (ESEP) and (2) a seismic risk evaluation. By letter dated May 7, 2013 (NRC, 2013a), the NRC determined that the modified schedule was acceptable and by letter dated August 28, 2013 (NRC, 2013c),
the NRC determined that the updated GMM (EPRI, 2013) is an acceptable GMM for use by CEUS plants in developing a plant-specific GMRS. By letter dated April 9, 2013 (Pietrangelo,
2013), industry agreed to follow the SPID to develop the SHSR for existing nuclear power plants.
By letter dated September 12, 2013 (Jacobs, 2013), Entergy Nuclear Operations, Inc. (Entergy, the licensee) submitted at least partial site response information for Waterford Steam Electric Station (Waterford). By letter dated March 27, 2014 (Chisum, 2014), the licensee submitted its SHSR.
2.0 REGULATORY BACKGROUND The structures, systems, and components (SSCs) important to safety in operating nuclear power plants are designed either in accordance with, or meet the intent of Appendix A to 10 CFR Part 50, General Design Criteria (GDC) 2: "Design Bases for Protection Against Natural Phenomena;" and Appendix A to 10 CFR Part 100, "Reactor Site Criteria." The GDC 2 states that SSCs important to safety at nuclear power plants shall be designed to withstand the effects of natural phenomena such as earthquakes, tornadoes, hurricanes, floods, tsunami, and seiches without loss of capability to perform their safety functions.
For initial licensing, each licensee was required to develop and maintain design bases that, as defined by 10 CFR 50.2, identify the specific functions that an SSC of a facility must perform, and the specific values or ranges of values chosen for controlling parameters as reference bounds for the design. The design bases for the SSCs reflect appropriate consideration of the most severe natural phenomena that had been historically reported for the site and surrounding area. The design bases also considered limited accuracy, quantity, and period of time in which the historical data have been accumulated.
The seismic design bases for currently operating nuclear power plants were either developed in accordance with, or meet the intent of GDC 2 and 10 CFR Part 100, Appendix A Although the regulatory requirements in Appendix A to 10 CFR Part 100 are fundamentally deterministic, the NRC process for determining the seismic design-basis ground motions for new reactor applications after January 10, 1997, as described in 10 CFR 100.23, requires that uncertainties be addressed through an appropriate analysis such as a probabilistic seismic hazard analysis (PSHA).
Section 50.54(f) of 10 CFR states that a licensee shall at any time before expiration of its license, upon request of the Commission, submit written statements, signed under oath or affirmation, to enable the Commission to determine whether or not the license should be modified, suspended, or revoked. On March 12, 2012, the NRC staff issued requests for licensees to reevaluate the seismic hazards at their sites using present-day NRC requirements and guidance, and identify actions planned to address plant-specific vulnerabilities associated with the updated seismic hazards. to Enclosure 1 of the 50.54(f) letter described an acceptable approach for performing the seismic hazard reevaluation for plants located in the CEUS. Licensees are expected to use the CEUS Seismic Source Characterization (CEUS-SSC) model in NUREG- 2115 (NRC, 2012b) along with the appropriate EPRI (2004, 2006) GMMs. The SPID provided further guidance regarding the appropriate use of GMMs for the CEUS. Specifically,
Section 2.3 of the SPID recommended the use of the updated GMM (EPRI, 2013) and, as such, licensees used the NRG-endorsed updated EPRI GMM instead of the older EPRI (2004, 2006)
GMM to develop PSHA base rock hazard curves. Finally, Attachment 1 requested that licensees conduct an evaluation of the local site response in order to develop site-specific hazard curves and GMRS for comparison with the plant SSE.
2.1 Screening Evaluation Results By letter dated March 27, 2014 (Chisum, 2014), the licensee provided the SHSR for Waterford.
The licensee's SHSR indicated that the plant GMRS was bounded by the SSE over the frequency range of 1 to 10 Hertz (Hz). As such, the licensee stated that neither a seismic risk evaluation nor a SFP evaluation will be performed. Additionally, due to only minor exceedances at frequencies above 10 Hz, the licensee indicated that a HF confirmation will not be performed because of the damping effect of the soil-structure system on high frequencies.
On May 9, 2014 (NRC, 2014), the NRC staff issued a letter providing the outcome of its 30-day screening and prioritization evaluation. As indicated in the letter, the NRC staff confirmed the licensee's screening results for all but the HF confirmation. The SSE bounds the GMRS over the frequency range of approximately 1 to 15 Hz. As such, a plant seismic risk evaluation and a SFP evaluation are not merited. Additionally, the NRC staff confirmed that, contrary to the licensee's conclusion, a HF confirmation for Waterford is merited because the GMRS exceeds the SSE above approximately 15 Hz.
3.0 TECHNICAL EVALUATION
The NRC staff evaluated the licensee's submittal to determine if the provided information responded appropriately to Enclosure 1 of the 50.54(f) letter with respect to characterizing the reevaluated seismic hazard.
3.1 Plant Seismic Design-Basis Enclosure 1 of the 50.54(f) letter requests the licensee provide the SSE ground motion values, as well as the specification of the control point elevation(s) for comparison to the GMRS. For operating reactors licensed before 1997, the SSE is the plant licensing basis ground motion and is characterized by (1) a peak ground acceleration (PGA) value which anchors the response spectra at high frequencies (typically at 33 Hz for the existing fleet of nuclear power plants); (2) a response spectrum shape which depicts the amplified response at all frequencies below the PGA; and (3) a control point where the SSE is defined.
In Section 3.1 of itsSHSR, the licensee described its seismic design-basis for Waterford. The licensee stated that the SSE for the Waterford site has a Newmark shape and is defined by a peak ground acceleration of 0.1g. The licensee specified that the control point elevation for the SSE is located at the bottom of the common mat supporting the nuclear island at elevation -47 ft. (-14.3 m).
Based on its review of the licensee's submittal and the Updated Final Safety Analysis Report (UFSAR) (Entergy, 2013), the NRC staff confirms that the licensee's SSE, as well as the SSE
control point elevation are consistent with information in the Waterford UFSAR and guidance in the SPID.
3.2 Probabilistic Seismic Hazard Analysis In Section 2.2 of its SHSR, the licensee stated that, in accordance with the 50.54(f) letter and the SPID, it performed a PSHA using the CEUS-SSC model and the updated EPRI GMM for the CEUS (EPRI, 2013). The licensee used a minimum magnitude cutoff of M5.0, as specified in the 50.54(f) letter. The licensee further stated that it included the CEUS-SSC background sources out to a distance of 400 mi (640 km) around the site and included the Charleston, Commerce, Eastern Rift Margin-North, Eastern Rift Margin-South, Marianna, Meers, New Madrid Fault System, and Wabash Valley Repeated Large Magnitude Earthquake (RLME) sources, which lie within 620 mi (1,000 km) of Waterford. The RLME sources are those source areas or faults for which more than one large magnitude (M ~ 6.5) earthquake has occurred in the historical or paleo-earthquake (geologic evidence for prehistoric seismicity) record. The licensee used 60 percent of the Gulf and 40 percent of the mid-continent versions of the updated EPRI GMM for each of the CEUS-SSC sources. Consistent with the SPID, the licensee did not provide its base rock seismic hazard curves since a site response analysis is necessary to determine the control point seismic hazard curves. The licensee provided its control point seismic hazard curves in Section 2.3.7 of the SHSR. The staff's review of the licensee's control point seismic hazard curves is provided in Section 3.3 of this staff assessment.
As part of its confirmatory analysis of the licensee's GMRS, the NRC staff performed PSHA calculations for base rock site conditions at the Waterford site. As input, the NRC staff used the CEUS-SSC model as documented in NUREG-2115 (NRC, 2012b) along with the updated EPRI GMM (EPRI, 2013). Consistent with the guidance provided in the SPID, the NRC staff included all CE US-SSC background seismic sources within a 310 mi (500 km) radius of the Waterford site. In addition, the NRC staff included the Charleston, Commerce, Eastern Rift Margin-North, Eastern Rift Margin-South, Meers, Marianna, New Madrid Fault System, and Wabash Valley RLME sources, which lie within 620 km (1,000 mi) of the Waterford site. For each of the CEUS- SSC sources used in the PSHA, the NRC staff used the Gulf version of the updated EPRI GMM.
Based on its review of the SHSR, the NRC staff concludes that the licensee appropriately followed the guidance provided in the SPID for selecting the PSHA input models and parameters for the site. This includes the licensee's use and implementation of the CE US-SSC model and the updated EPRI GMM.
3.3 Site Response Evaluation After completing PSHA calculations for reference rock conditions, Attachment 1 to Enclosure 1 of the 50.54(f) letter requests that licensees provide a GMRS developed from the site-specific seismic hazard curves at the control point elevation. In addition, the 50.54(f) letter specifies that the subsurface site response model, for both soil and rock sites, should extend to sufficient depth to reach the generic or base rock conditions as defined in the GMMs used in the PSHA.
To develop site-specific hazard curves at the control point elevation, Attachment 1 requests that licensees perform a site response analysis.
Detailed site response analyses were not typically performed for many of the older operating plants; therefore, Appendix B of the SPID provides detailed guidance on the development of site-specific amplification factors (including the treatment of uncertainty) for sites that do not have detailed, measured soil and rock parameters to extensive depths.
The purpose of the site response analysis is to determine the site amplification that would occur as a result of bedrock ground motions propagating upwards through the soil/rock column to the surface. The critical parameters that determine what frequencies of ground motion are affected by the upward propagation of bedrock motions are the layering of soil and/or soft rock, the thicknesses of these layers, the shear-wave velocities and low-strain damping of these layers, and the degree to which the shear modulus and damping change with increasing input bedrock amplitude. To develop site-specific hazard curves at the control point, the licensee performed a site response analysis.
3.3.1 Site Base Case Profiles The licensee provided detailed site profile descriptions in Sections 2.3.1 and 2.3.2 of its SHSR based on information provided in the UFSAR (Entergy, 2013) and the guidance in Appendix B of the SPID. The Waterford site is located in the Gulf Coastal Plain geologic province within the Mississippi River Deltaic plain physiographic province. According to the licensee, base rock conditions occur at a depth of approximately 40,000 ft. (12,200 m). Overlying this is a thick sequence of sediments and sedimentary rocks composed of approximately 5,400 (1,646 m) of soils overlying nearly 35,000 ft. (10,700 m) of firm sedimentary rock.
Concerning the subsurface layers at the Waterford site, the licensee stated that surficial deposits consist of 500 ft. (152 m) of flat lying sediments composed of interbedded sands and clays. lnterbedded sands and clays representing different geologic units and with varying lithologies extend from this depth to approximately 7,500 ft. (2,286 m) and overlie thinly interbedded shales and sandstones.
The licensee developed three base case shear-wave velocity profiles for the Waterford site using shear-wave velocities determined from in-situ shear and compressional wave velocity measurements of the uppermost 173 ft. (53 m) of the subsurface. The licensee extrapolated these values to a depth of 515 ft. (157 m) using geologic information available at the site. Below this depth, the licensee used a template profile from the SPID to extend the best-estimate base case profile to a depth of 4,000 ft. (1,219 m). The licensee stated that velocity variations at depths greater than 4,000 ft. (1,219 m) are expected to have little impact on the site response at frequencies below the 0.5 Hz minimum defined by the GMM. The licensee calculated lower and upper base case shear-wave velocity profiles using a scale factor of 1.25 over the upper 173 ft.
(53 m) and a factor of 1.57 below. These scale factors are consistent with a natural log standard deviation of 0.2 and 0.35 for the upper and lower portions of the profiles respectively.
Figure 3.3-1 of this assessment shows the licensee's three base case shear-wave velocity profiles.
In Section 2.3.2.1 of its SHSR, the licensee stated that no site-specific dynamic material properties were available for the Waterford site. Therefore, the licensee followed the SPID guidance and assumed the soil material behavior over the upper 500 ft. (150 m) could be modeled using either EPRI cohesionless soil or Peninsular Range shear modulus and damping curves. Consistent with the SPID, the EPRI soil curves were considered appropriate for the nonlinear responses and the Peninsular Range curves were assumed to be an equally plausible alternative for linear response.
The licensee also considered the impact of kappa, or small strain damping, on site response.
Kappa is measured in units of seconds (sec), and is the damping contributed by both intrinsic hysteretic damping as well as scattering due to wave propagation in heterogeneous material.
For the Waterford site, with greater than 3,000 ft. (914 m) of soil, the licensee assumed kappa value is 0.04 sec for the base, lower, and upper profiles. The licensee stated that uncertainty in kappa is accounted for by the use of two different models for the dynamic material properties.
To account for randomness in material properties across the plant site, the licensee stated that it randomized its base case profiles following guidance in Appendix B of the SPID. In addition, the licensee stated that it randomized the depth to reference rock +/-1,200 ft. (366 m), which corresponds to nearly 30 percent of the total profile thickness. The licensee stated that this randomization did not represent actual uncertainty in the depth to base rock, but was used to broaden the spectral peaks in the amplification functions.
3.3.2 Site Response Method and Results In Section 2.3.4 of its SHSR, the licensee stated that it followed the guidance in Appendix B of the SPID to develop input ground motions for the site response analysis, and in Section 2.3.5, the licensee described its implementation of the random vibration theory (RVT) approach to perform its site response calculations. Finally, Section 2.3.6 of the SHSR shows the resulting amplification functions and associate uncertainties for the eleven input loading levels for the each base case profile.
In order to develop probabilistic site-specific control point hazard curves, as requested in Requested Information Item (1) of the 50.54(f) letter, the licensee used Method 3, described in Appendix B-6.0 of the SPID. The licensee's use of Method 3 involved computing the site- specific control point elevation hazard curves for a broad range of spectral accelerations by combining the site-specific reference rock hazard curves, determined from the initial PSHA (Section 3.2 of this assessment), and the amplification function and their associated uncertainties, determined from the site response analysis.
3.3.3 Staff Confirmatory Analysis To confirm the licensee's site response analysis, the NRC staff performed site response calculations for the Waterford site. The NRC staff independently developed a shear-wave velocity profile, damping values, and modeled non-linear behavior of the subsurface materials using geologic information and measurements provided in the Waterford FSAR and guidance in Appendix B of the SPID. For its site response calculations, the NRC staff employed the RVT
approach and developed input ground motions in accordance with Appendix B of the SPID following the guidance for sites with limited at site information.
Geotechnical investigations performed during initial licensing include, refraction surveys, up- hole and cross-hole surveys, and cyclic triaxial testing of the shallow subsurface. The NRC staff relied on this in-situ data to develop its base case shear wave velocity profile to the depth of approximately 400 ft. (122 m). The NRC staff extended its profile to a depth of 8,000 ft.
(2,438 m) using the velocity gradient recommended in the SPID. To account for uncertainty in the shear wave velocity, the NRC staff used a natural log standard deviation of 0.2 to calculate upper and lower base case profiles. Figure 3.3-1 of this assessment shows a comparison of the three base case velocity profiles developed by the licensee with those developed by the NRC staff. Profiles developed by the licensee are similar in shape to those developed by the NRC staff; however, the profiles developed by the NRC staff extend to a greater depth and have higher velocities at depths greater than approximately 2,500 ft. (762 m).
Consistent with guidance in the SPID, the NRC staff developed two damping profiles that incorporate different degrees of non-linearity and model the shear modulus degradation and damping in its site response analysis. Similar to the licensee, the NRC staff used the EPRI (1993) curves to model the upper limit of non-linearity at the site and the Peninsular Range curves to model the lower limit.
The NRC staff also considered the impact of kappa on site response. The NRC staff followed the guidance in the SPID for sites with greater than 3,000 ft. (914 m) of soil overlying base rock to determine a base case kappa value of 0.04 sec. To model the uncertainty in kappa, the NRC staff used a natural log standard deviation of 0.4 to calculate lower and upper kappa values in each profile. This approach results in nine kappa values for the staff's site response analysis, which range from 0.019 to 0.053 sec.
Figure 3.3-2 of this assessment shows a comparison of the staff's and the licensee's median site amplification functions and uncertainties (+/-1 standard deviation) for two of the eleven input loading levels. Overall, the staff's and the licensee's site amplification functions are consistent, with a peak at approximately 5 Hz. Minor differences in site amplification functions are due primarily to difference in the staff's and licensee's site velocity profiles. As shown in Figure 3.3- 3 of this assessment, these differences in site response have only a minor impact on the control point seismic hazard curves and the resulting GMRS, discussed below. Appendix B of the SPID provides guidance for performing site response analyses, including capturing the uncertainty for sites with less subsurface data. However, the guidance is neither entirely prescriptive nor comprehensive. As such, various approaches in performing site response analyses, including the modeling of uncertainty, are acceptable for the 50.54(f) response.
In summary, the NRC staff concludes that the licensee's site response was conducted using present-day guidance and methodology, including the NRC-endorsed SPID. The NRC staff performed independent calculations to confirm that the licensee's amplification factors and control point hazard curves adequately characterize the site response, including the uncertainty associated with the subsurface material properties, for the Waterford site.
3.4 Ground Motion Response Spectra In Section 2.4 of its SHSR, the licensee stated that it used the control point hazard curves, described in SHSR Section 2.3.7, to develop the 10-4 and 10-5 (mean annual frequency of exceedance) uniform hazard response spectra (UHRS) and then computed the GMRS using the criteria in RG 1.208. The NRC staff independently calculated the 10-4 and 10-5 UHRS using the results of its confirmatory PSHA and site response analysis, as described in Sections 3.2 and 3.3 of this staff assessment, respectively. Figure 3.4-1 of this assessment shows a comparison of the GMRS determined by the licensee to that determined by the NRC staff. As shown in Figure 3.4-1, the licensee's GMRS shape is very similar to that calculated by the NRC staff.
The staff confirms that the licensee used the present-day guidance and methodology outlined in RG 1.208 and the SPID to calculate the horizontal GMRS, as requested in the 50.54(f) letter.
The staff performed both a PSHA and site response confirmatory analysis and achieved results consistent with the licensee's horizontal GMRS. As such, the NRC staff concludes that the GMRS determined by the licensee adequately characterizes the reevaluated hazard for the Waterford site. Therefore, this GMRS is suitable for use in subsequent evaluations and confirmations, as needed, for the licensee's response to the 50.54(f) letter.
4.0 CONCLUSION
The NRC staff reviewed the information provided by the licensee for the reevaluated seismic hazard for the Waterford site. Based on its review, the NRC staff concludes that the licensee conducted the seismic hazard reevaluation using present-day methodologies and regulatory guidance, appropriately characterized the site given the information available, and met the intent of the guidance for determining the reevaluated seismic hazard. Based upon the preceding analysis, the NRC staff concludes that the licensee provided an acceptable response to Requested Information Items (1) - (3) and (5) - (7) and the comparison portion to Item (4),
identified in Enclosure 1 of the 50.54(f) letter. Further, the licensee's reevaluated seismic hazard is acceptable to address other actions associated with NTTF Recommendation 2.1: Seismic.
In reaching this determination, NRC staff confirms the licensee's conclusion that the licensee's GMRS for the Waterford site is bounded by the SSE in the 1 to 10 Hz range, but exceeds the SSE in a portion of the frequency range above 10 Hz. As such, a seismic risk evaluation and SFP evaluation (i.e., Requested Information Items (8) and (9)) are not merited, however a HF confirmation (i.e., Requested Information Item (4)) is merited. The NRC review and acceptance of Entergy's HF confirmation for the Waterford site will complete Seismic Hazard Evaluation identified in Enclosure 1 of the 50.54(f) letter.
REFERENCES Note: ADAMS Accession Nos. refers to documents available through NRC's Agencywide Documents Access and Management System (ADAMS). Publicly-available ADAMS documents may be accessed through http://www.nrc.gov/reading-rm/adams.html.
U.S. Nuclear Regulatory Commission Documents and Publications NRC (U.S. Nuclear Regulatory Commission), 2007, A Performance-based Approach to Define the Site-Specific Earthquake Ground Motion, Regulatory Guide (RG) 1.208, March 2007.
NRC (U.S. Nuclear Regulatory Commission), 2011a, "Near-Term Report and Recommendations for Agency Actions Following the Events in Japan," Commission Paper SECY-11-0093, July 12, 2011, Adams Accession No. ML11186A950.
NRC (U.S. Nuclear Regulatory Commission), 2011 b, "Recommendations for Enhancing Reactor Safety in the 21 51 Century: The Near-Term Task Force Review of Insights from the Fukushima Dai-lchi Accident," Enclosure to SECY-11-0093, July 12, 2011, ADAMS Accession No. ML11186A950.
NRC (U.S. Nuclear Regulatory Commission), 2011c, "Recommended Actions to be Taken Without Delay from the Near-Term Task Force Report," Commission Paper SECY 0124, September 9, 2011, Adams Accession No. ML11245A158.
NRC (U.S. Nuclear Regulatory Commission), 2011 d, "Prioritization of Recommended Actions to be Taken in Response to Fukushima Lessons Learned," Commission Paper SECY 0137, October3, 2011, Adams Accession No. ML11272A111.
NRC (U.S. Nuclear Regulatory Commission), 2012a, letter from Eric J. Leeds, Director, Office of Nuclear Reactor Regulation and Michael R. Johnson, Director, Office of New Reactors, to All Power Reactor Licensees and Holders of Construction Permits in Active or Deferred Status, March 12, 2012, ADAMS Accession No. ML12053A340.
NRC (U.S. Nuclear Regulatory Commission), 2012b, "Central and Eastern United States Seismic Source Characterization for Nuclear Facilities", NUREG-2115, ADAMS stores the NUREG as multiple ADAMS documents, which are most easily accessed through the web page http://www.nrc.gov/reading-rm/doc-collections/nuregs/staff/sr2115/.
NRC (U.S. Nuclear Regulatory Commission), 2013a. Letter From Eric J. Leeds, to Joseph Pollock, Executive Director NEI, Acceptance Letter for NEI Submittal of Augmented Approach, Ground Motion Model Update Project, and 10 CFR 50.54(f) Schedule Modifications Related to the NTTF Recommendation 2.1, Seismic Reevaluations, May 7, 2013, ADAMS Accession No. ML13106A331.
NRC (U.S. Nuclear Regulatory Commission), 2013b, letter from David L. Skeen, Director, Japan Lessons-Learned Directorate, to Joseph E. Pollock, Executive Director, Nuclear Energy Institute, Endorsement of Electric Power Research Institute Draft Report 1025287,
"Seismic Evaluation Guidance," February 15, 2013, ADAMS Accession No. ML12319A074.
NRC (U.S. Nuclear Regulatory Commission), 2013c. Letter from D. L. Skeen (NRC) to K. A Keithline (NEI), Approval of Electric Power Research Institute Ground Motion Model Review Project Final Report for Use by Central and Eastern United States Nuclear Power Plants, August 28, 2013 ADAMS Accession No. ML13233A102.
NRC (U.S. Nuclear Regulatory Commission) 2014a. Letter from Eric J. Leeds, Director, Office of Nuclear Reactor Regulation to All Power Reactor Licensees and holders of Construction Permits in Active or Deferred Status, Seismic Screening and Prioritization Results Regarding Information Pursuant to Title 10 of the Code of Federal Regulations 50.54(f)
Regarding Seismic Hazard Reevaluations for Recommendations 2.1 of the Near-Term Task Force Review of Insights, May 9, 2014, ADAMS Accession No. ML14111A147.
Other References Chisum, M. 2014, Letter from M. Chisum (Entergy Nuclear Operations, Inc.) to NRC, Response to NRC Request for Information Pursuant to 10 CFR 50.54(f) Regarding Recommendation 2.1 of the Near-Term Task Force Review of Insights from the Fukushima Dai-ichi Accident, March 27, 2014, ADAMS Accession No. ML14086A427.
Electric Power Research Institute (EPRI), 2004. EPRI Report 1009684, "CEUS Ground Motion Project Final Report." Palo Alto, CA, 2004.
Electric Power Research Institute (EPRI), 2006. EPRI Report 1014381, "Truncation of the Log normal Distribution and Value of the Standard Deviation for Ground Motion Models in the Central and Eastern United States." Palo Alto, CA, 2006.
Electric Power Research Institute (EPRI), 2012. EPRI Report 1025287 "Seismic Evaluation Guidance, Screening, Prioritization and Implementation Details [SPID] for the Resolution of Fukushima Near-Term Task Force Recommendation 2.1: Seismic" November 27, 2012, ADAMS Accession No. ML12333A170.
Electric Power Research Institute (EPRI), 2013. EPRI Report 3002000717 "EPRI (2004, 2006)
Ground-Motion Model Review Project Final Report," Palo Alto, CA, 2013.
Entergy (2013). "Waterford Steam Electric Station Updated Final Safety Analysis Report Unit 3,"
Revision 307, Docket No. 50-382, 2013.
Jacobs, D. 2013, Letter from D. Jacobs (Entergy Nuclear Operations, Inc.) to NRC, Response to NRC Request for Information Pursuant to 10 CFR 50.54(f) Regarding the Seismic Aspects of Recommendation 2.1 of the Near-Term Task Force Review of Insights from the Fukushima Dai-ichi Accident - 1.5 Year Response for CEUS Sites, September 12, 2013, ADAMS Accession No. ML13259A277.
Keithline, 2012, Letter from Kimberly Keithline, Senior Project Manager, NEI, to David L. Skeen, Director, Japan Lessons Learned Project Directorate, NRC, Final Draft of Industry Seismic Evaluation Guidance (EPRI 1025287), November 27, 2012, ADAMS Accession No. ML12333A168.
Keithline, 2013, Submittal of EPRI (2004, 2006) Ground Motion Model Review Final Report, June 3, 2013, ADAMS Accession No. ML13170A378.
Pietrangelo, 2013. Letter from A. R. Pietrangelo (NEI) to D. L. Skeen (NRC), Proposed Path Forward for NTTF Recommendation 2.1: Seismic Reevaluations, April 9, 2013, ADAMS Accession No. ML13101A379.
Figure 3.3-1 Plot of Staff's and Licensee's Base Case Shear-Wave Velocity Profiles for the Waterford Site Shear Wave Velocity (ft/s) 0 2000 4000 6000 8000 10000 0
1000 2000
- - - - lower g4000
~
c.
~ 5000
- -----1 I
- - - - upper
- - licensee 6000 I_ - - , '-----, *- - - - - - - - -
1
-- upper I I I
7000
- - lower 8000 9000
Figure 3.3-2 Plot Comparing the Staff's and the Licensee's Median Amplification Functions and Uncertainties for the Waterford site.
4.5 ..,. I 4
3.5
.... - - - - NRC_0.3g
....0(,) 3
- as c 2.5 0
as
- - - - NRC_0.3g_sigma
- - - - NRC_0.05 g
(,)
2 - - - - NRC_0.05_sigma
~
0.. - - licensee 0.0495g
~ 1.5 licensee 0.0495g sigma
- - licensee 0.292 g
- - licensee 0.292 g sigma 0.5 0
0.1 10 100 Frequency (Hz)
~-----
Figure 3.3-3 Plot Comparing the Staff's and the Licensee's Mean Control Point Hazard Curves at a Variety of Frequencies for the Waterford site 1.00E-01 1.00E-02 Q)
(.)
c
.§ 1.00E-03 Q)
Q)
(.)
>< - - - NRC 1 Hz W 1.00E-04
>. - - - NRC 10 Hz
(.)
c Q)
NRC pga
@- 1.00E-05 Q)
.;: - - Licensee 1 Hz (ii - - licensee 1O Hz
@ 1.00E-06 c - - licensee pga
<(
1.00E-07 1.00E-08 0.1 Spectral Acceleration {g)
Figure 3.4-1 Comparison of the Staff's GMRS with Licensee's GMRS and the SSE for the Waterford site 1.4 1.2 1 ...
- §o.a r--
r--
<(
CJ) 0.6 0.4 - I 0.2 0 - -~
- J.. .....__._ _ -....L.- .J..-_.J..-~
0.1 1 10 100 Frequency (Hz)
-Licensee SSE - Licensee GMRS NRC GMRS l
ML15335A050 *via email OFFICE NRR/JLD/JHMB/PM NRR/JLD/LA NRO/DSEA/RGS/BC* NRR/JLD/JHMB/BC NRR/JLD/JHMB/PM NAME FVega Slent DJackson MS hams FVega DATE 12/07/2015 12/04/2015 11/18/2015 12/13/2015 12/15/2015