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{{#Wiki_filter:W. R. | {{#Wiki_filter:W. R. Gfdeon H. B. Robinson Steam Electric Plant Unit 2 DUKE Site Vice President ENERGYDuke Engy Pogres ENERG3581 West Entrance Romo Hartsville, SC 29550 0: 843 857 1701 F" 843 857 1319 Rmndy.Gideon*duke-energy.com 10 CFR 50.54(f)Serial: RNP-RN14-0013 MAR 3 12014 U.S. Nuclear Regulatory Commission Attn: Document Control Desk 11555 Rockville Pike Rockville, MD 20852 H. B. ROBINSON STEAM ELECTRIC PLANT, UNIT NO. 2 DOCKET NO. 50-261 / RENEWED LICENSE NO. DPR-23 | ||
==Subject:== | ==Subject:== | ||
Seismic Hazard Evaluation, Response to NRC 10 CFR 50.54(f) Request for Information Pursuant to Title 10 of the Code of Federal Regulations 50.54(f)Regarding Recommendations 2.1, 2.3 and 9.3 of the Near-Term Task Force Review of Insights from the Fukushima Dai-ichi Accident | |||
Seismic Hazard Evaluation, Response to NRC 10 CFR 50.54(f) | |||
Request | |||
==References:== | ==References:== | ||
: 1. NRC letter, Request for Information Pursuant to Title 10 of the Code of | : 1. NRC letter, Request for Information Pursuant to Title 10 of the Code of Federal Regulations 50.54(o Regarding Recommendations 2.1, 2.3, and 9.3, of the Near-Term Task Force Review of Insights from the Fukushima Dai-ichi Accident, dated March 12, 2012 (ADAMS Accession Number ML12056A046) | ||
: 2. NRC letter, Endorsement of EPRI Final Draft Report 1025287, "Seismic Evaluation Guidance," dated February 15, 2013 (ADAMS Accession Number ML1 2319A074)3. EPRI Report 1025287, Seismic Evaluation Guidance: | |||
: 2. NRC letter, Endorsement of EPRI Final Draft Report 1025287, "Seismic Evaluation Guidance," | Screening, Prioritization and Implementation Details (SPID) for the Resolution of Fukushima Near-Term Task Force Recommendation 2.1: Seismic, dated February 2013 (ADAMS Accession Number ML1 2333A1 70)4. NEI letter, Proposed Path Forward for NTTF Recommendation 2.1: Seismic Reevaluations, dated April 9, 2013 (ADAMS Accession Number ML13101A319) | ||
dated February 15, 2013 (ADAMS Accession Number ML1 2319A074) | : 5. NRC letter, Electric Power Research Institute Final Draft Report XXXXXX, "Seismic Evaluation Guidance: | ||
Screening, Prioritization | |||
: 5. NRC letter, Electric Power Research Institute Final Draft Report XXXXXX, " | |||
Augmented Approach for the Resolution of Fukushima Near-Term Task Force Recommendation | Augmented Approach for the Resolution of Fukushima Near-Term Task Force Recommendation | ||
: 2. 1: Seismic, "as an Acceptable Alternative | : 2. 1: Seismic, "as an Acceptable Alternative to the March 12, 201Z Information Request for Seismic Reevaluations, dated May 7, 2013 (ADAMS Accession Number ML13106A331) | ||
: 6. NEI Letter, Seismic Evaluations for Plants in the Central and Eastern United States,dated March 12,2014 (ADAMS Accession Nos. ML14083A584, ML14083A586 | : 6. NEI Letter, Seismic Evaluations for Plants in the Central and Eastern United States, dated March 12,2014 (ADAMS Accession Nos. ML14083A584, ML14083A586 and ML14083A587) 4A0o U. S. Nuclear Regulatory Commission Serial: RNP-RA/14-0013 Page 3 of 3 Ladies and Gentlemen: | ||
On March 12, 2012, the Nuclear Regulatory Commission (NRC) issued Reference 1 to all | On March 12, 2012, the Nuclear Regulatory Commission (NRC) issued Reference 1 to all power reactor licensees and holders of construction permits in active or deferred status. Enclosure 1 of Reference 1 requested each addressee in the Central and Eastern United States (CEUS) to submit a written response consistent with the requested seismic hazard evaluation information (items 1 through 7) by September 12, 2013. By letter dated February 15, 2013, the NRC issued Reference 2, endorsing the Reference 3 industry guidance for responding to the seismic evaluation in Reference | ||
: 1. Section 4 of Reference 3 identifies the detailed information to | : 1. Section 4 of Reference 3 identifies the detailed information to be included in the seismic hazard evaluation submittals. | ||
On April 9, 2013, the Nuclear Energy Institute (NEI) submitted Reference 4 to the NRC,requesting NRC agreement to delay submittal of part of the CEUS seismic hazard evaluation information so that an update to the Electric Power Research Institute (EPRI) (2004, 2006)ground motion attenuation model could be completed and used to develop that information. | On April 9, 2013, the Nuclear Energy Institute (NEI) submitted Reference 4 to the NRC, requesting NRC agreement to delay submittal of part of the CEUS seismic hazard evaluation information so that an update to the Electric Power Research Institute (EPRI) (2004, 2006)ground motion attenuation model could be completed and used to develop that information. | ||
NEI proposed that descriptions of subsurface materials and properties and base case velocity profiles (items 3a and 3b in Section 4 of Reference | |||
: 3) be submitted to the NRC by September 12, 2013, with the remaining seismic hazard and screening information submitted to the NRC | : 3) be submitted to the NRC by September 12, 2013, with the remaining seismic hazard and screening information submitted to the NRC by March 31, 2014. In Reference 5, the NRC agreed with this recommendation. | ||
Reference 3 contains industry guidance and detailed information to be included in the | Reference 3 contains industry guidance and detailed information to be included in the Seismic Hazard Evaluation submittals. | ||
The attached Seismic Hazard Evaluation for H. B. | The attached Seismic Hazard Evaluation for H. B. Robinson Steam Electric Plant, Unit No. 2 provides the information described in Section 4 of Reference 3 in accordance with the schedule identified in Reference | ||
: 4. As discussed in the Enclosure to | : 4. As discussed in the Enclosure to this letter, seismic hazard curves and a Ground Motion Response Spectrum (GMRS) were developed using current methodology. | ||
This GMRS is compared to the design basis | This GMRS is compared to the design basis Safe Shutdown Earthquake (SSE) response spectrum and the Individual Plant Examination of External Events (IPEEE) High Confidence of Low Probability of Failure (HCLPF) spectrum in the Enclosure. | ||
As discussed within Reference 1, NRC acknowledged that the current regulatory approach | As discussed within Reference 1, NRC acknowledged that the current regulatory approach and the resultant plant capabilities provides reasonable confidence that an accident with consequences similar to the Fukushima event is unlikely with nuclear power plants located in the United States. The NRC concluded that continued plant operation does not pose an imminent risk to the public health and safety.By letter dated March 12, 2014 (Reference 9), NEI provided the NRC with seismic core damage risk estimates based on updated seismic hazard information as it applies to operating nuclear reactors in the CEUS, which includes H. B. Robinson Steam Electric Plant, Unit No. 2. These risk assessments continue to support the conclusions of the NRC Generic Issue-1 99"Safety/Risk Assessment" and indicate that current seismic design of operating reactors provide adequate protection and safety margin to withstand potential earthquakes that exceed the original design basis.In accordance with Enclosure 1 of Reference 1, H. B. Robinson Steam Electric Plant, Unit No. 2 screens in for performing a seismic probabilistic risk assessment (SPRA).This letter contains no new regulatory commitments. | ||
U. S. Nuclear Regulatory Commission Serial: RNP-RA/14-0013 Page 3 of | U. S. Nuclear Regulatory Commission Serial: RNP-RA/14-0013 Page 3 of 3 If you have any questions or require additional information, please contact Richard Hightower, Manager, Nuclear Regulatory Affairs at (843)-857-1329. | ||
I declare under the penalty of perjury that the foregoing is true and correct.Executed on MAR 3 12014 Sincerely, W. R. Gideon Site Vice President WRG/shc | |||
I declare under the penalty of perjury that the foregoing is true and correct.Executed on MAR 3 | |||
==Enclosure:== | ==Enclosure:== | ||
Seismic Hazard Evaluation cc: Mr. K. M. Ellis, NRC Senior Resident Inspector Mr. S. P. Lingam, NRC Project Manager, | Seismic Hazard Evaluation cc: Mr. K. M. Ellis, NRC Senior Resident Inspector Mr. S. P. Lingam, NRC Project Manager, NRR Mr. V. M. McCree, NRC Region II Administrator U. S. Nuclear Regulatory Commission Enclosure to Serial: RNP-RA/14-0013 39 Pages including this cover ENCLOSURE SEISMIC HAZARD EVALUATION FOR H. B. ROBINSON STEAM ELECTRIC PLANT, UNIT NO. 2 DOCKET NO. 50-261 / RENEWED LICENSE NO. DPR-23 TABLE OF CONTENTS Section Page 1.0 Introduction | ||
........................................................................................ | ........................................................................................ | ||
1 2.0 Seismic Hazard Reevaluation | |||
................................................................ | ................................................................ | ||
2 2.1 Regional and Local Geology ............................................................... | |||
3 2.2 Probabilistic Seismic Hazard Analysis .................................................. | |||
.................................................. | 4 2.2.1 Probabilistic Seismic Hazard Analysis Results .................................... | ||
4 2.2.2 Base Rock Seismic Hazard Curves ................................................ | |||
9 2.3 Site Response Evaluation | |||
.................................................................. | .................................................................. | ||
9 2.3.1 Description of Subsurface Material ................................................... | |||
................................................... | 9 2.3.2 Development of Base Case Profiles and Nonlinear Material Properties | ||
...... 11 2.3.3 Randomization of Base Case Profiles .............................................. | |||
...... | 14 2.3.4 Input Spectra .............................................................................. | ||
.............................................. | 15 2.3.5 Methodology | ||
............................................................................... | ............................................................................... | ||
15 2.3.6 Amplification Functions | |||
................................................................. | ................................................................. | ||
15 2.3.7 Control Point Seismic Hazard Curves .............................................. | |||
22 2.4 Ground Motion Response Spectrum .................................................... | |||
.................................................... | 22 3.0 Safe Shutdown Earthquake Ground Motion ............................................ | ||
24 3.1 Description of Spectral Shape and Anchor Point ..................................... | |||
24 3.2 Control Point Elevation | |||
...................................................................... | ...................................................................... | ||
25 4.0 Screening Evaluation | |||
.......................................................................... | .......................................................................... | ||
25 4.1 Risk Evaluation Screening (1 to 10 Hz) .................................................. | |||
26 4.2 High Frequency Screening | |||
(> 10 Hz) .................................................... | (> 10 Hz) .................................................... | ||
26 4.3 Spent Fuel Pool Evaluation Screening (1 to 10 Hz) ..................... | |||
. | .26 5.0 Interim Actions and Assessments | ||
.......................................................... | .......................................................... | ||
26 5.1 Expedited Seismic Evaluation Program ................................................ | |||
26 5.2 Seismic Risk Estimates | |||
....................................................................... | ....................................................................... | ||
27 5.3 Individual Plant Examination of External Events ...................................... | |||
27 5.4 Walkdowns to Address NRC Fukushima NTTF Recommendation 2.3 ............ | |||
27 6.0 Conclusions | |||
...................................................................................... | ...................................................................................... | ||
28 7.0 References | |||
................ | ................ | ||
............................... | ............................... | ||
29 Appendix A .................................................................................................. | |||
A- | A-1 i Seismic Hazard and Screening Report H.B. Robinson Steam Electric Plant (HBRSEP) Page 1 of 30 1.0 Introduction Following the accident at the Fukushima Dai-ichi nuclear power plant resulting from the March 11, 2011, Great Tohoku Earthquake and subsequent tsunami, the NRC Commission established a Near Term Task Force (NTTF) to conduct a systematic review of NRC processes and regulations and to determine if the agency should make additional improvements to its regulatory system. The NTTF developed a set of recommendations intended to clarify and strengthen the regulatory framework for protection against natural phenomena. | ||
Page 1 of | Subsequently, the NRC issued a 50.54(f) letter on March 12, 2012 (Reference 1), requesting information to assure that these recommendations are addressed by all U.S. nuclear power plants. The *50.54(f) letter requests that licensees and holders of construction permits under 10 CFR Part 50 reevaluate the seismic hazards at their sites against present-day NRC requirements. | ||
Depending on the comparison between the reevaluated seismic .hazard and the current design basis, the result is either no further risk evaluation or the performance of a seismic risk assessment. | |||
Subsequently, the NRC issued a 50.54(f) letter on March 12, 2012 (Reference 1), requesting information | Risk assessment approaches acceptable to the staff include a seismic probabilistic risk assessment (SPRA), or a seismic margin assessment (SMA). Based upon the risk assessment results, the NRC staff will determine whether additional regulatory actions are necessary. | ||
Depending on the comparison between the reevaluated seismic .hazard and the current design basis, | This report provides the information requested in items (1) through (7) of the "Requested Information" section and Attachment 1 of the 50.54(f) letter pertaining to NTTF Recommendation 2.1 for the H.B. Robinson Steam Electric Plant (HBRSEP) site, located in Darlington County, South Carolina (SC). In providing this information, HBRSEP followed the guidance provided in the Seismic Evaluation Guidance: | ||
Screening, Prioritization, and Implementation Details (SPID) for the Resolution of Fukushima Near-Term Task Force Recommendation 2.1: Seismic (EPRI 1025287, 2013) (Reference 2). The Augmented Approach, Seismic Evaluation Guidance: | |||
Augmented Approach for the Resolution of Fukushima Near-Term Task Force Recommendation 2.1: Seismic (EPRI 3002000704, 2013) (Reference 3), has been developed as the process for evaluating critical plant equipment as an interim action to demonstrate additional plant safety margin, prior to performing the complete plant seismic risk evaluations. | |||
This report provides the information requested in items (1) through (7) of the "Requested Information" section and Attachment 1 of the 50.54(f) letter pertaining to | The original geologic and seismic siting investigations for HBRSEP were performed using a detailed geologic study of the region and the site to establish the geologic suitability of the site for the nuclear unit. Additional data utilized in the geologic and seismic siting investigations were obtained from the U. S. Atomic Energy Commission (USAEC) Savannah River Operations Office (Appendix 2.5A of Reference 7), Dr.'s J. L. Stuckey and L. L. Smith (Appendix 2.5C of Reference 7), and Perry Byerly (Appendix 2.5D of Reference 7).The Safe Shutdown Earthquake (SSE) was developed based on evaluation of historic earthquake activity, regional and local geology, and recommendation of Dr. G. W. Housner of the California Institute of Technology. | ||
Screening, Prioritization, | The SSE was used for the design of seismic Class I systems, structures, and components. | ||
Seismic Hazard and Screening Report H.B. Robinson Steam Electric Plant (HBRSEP) Page 2 of 30 The General Design Criteria (GDC) in existence at the time HBRSEP was licensed (July, 1970)for operation were contained in Proposed Appendix A to 10CFR50, General Design Criteria for Nuclear Power Plants, published in the Federal Register on July 11, 1967. (Appendix A to 1 OCFR50, effective in 1971 and subsequently amended, is somewhat different from the proposed 1967 criteria.) | |||
Augmented Approach for the Resolution of Fukushima Near-Term Task Force Recommendation 2.1: Seismic (EPRI 3002000704, 2013) (Reference 3),has been developed as the process for evaluating critical plant equipment as an interim | HBRSEP was evaluated with respect to the proposed 1967 GDC and the original Final Safety Analysis Report (FSAR) (Reference | ||
The original geologic and seismic siting investigations for HBRSEP were performed using | : 7) contained a discussion of the criteria as well as a summary of the criteria by groups. FSAR, Sections 3.1.1.2 and 3.1.2 present that discussion without substantive change in order to preserve the original basis for licensing. | ||
In response to the 50.54(f) letter and following the guidance provided in the SPID (Reference 2), a seismic hazard reevaluation was performed. | |||
The SSE was used for the design of seismic Class | For screening purposes, a Ground Motion Response Spectrum (GMRS) was developed. | ||
Seismic Hazard and Screening | |||
Page 2 of | |||
HBRSEP was evaluated with respect to the proposed 1967 GDC | |||
: 7) contained a discussion of | |||
In response to the 50.54(f) letter and following the guidance provided in the SPID (Reference 2),a seismic hazard reevaluation was performed. | |||
For screening | |||
Based on the results of the screening evaluation, HBRSEP screens in for risk evaluation, a Spent Fuel Pool evaluation, and a High Frequency Confirmation. | Based on the results of the screening evaluation, HBRSEP screens in for risk evaluation, a Spent Fuel Pool evaluation, and a High Frequency Confirmation. | ||
2.0 Seismic Hazard Reevaluation HBRSEP is located in northwest Darlington County, SC, approximately 3 miles west-northwest of Hartsville, SC; 25 miles northwest of Florence, SC; 35 miles north-northeast of Sumter, SC;and 56 miles east-northeast of Columbia, SC. The plant is on the southwest shore of | 2.0 Seismic Hazard Reevaluation HBRSEP is located in northwest Darlington County, SC, approximately 3 miles west-northwest of Hartsville, SC; 25 miles northwest of Florence, SC; 35 miles north-northeast of Sumter, SC;and 56 miles east-northeast of Columbia, SC. The plant is on the southwest shore of Lake Robinson, a cooling impoundment of Black Creek. The site is located in the Coastal Plain physiographic province about 15 miles southeast of the Piedmont province. | ||
The Coastal Plain | The Coastal Plain is composed of largely unconsolidated sediments above a slightly sloping surface of crystalline rock. The basement crystallines in the Piedmont and below the Coastal Plain are composed largely of granite, gneiss, phyllite, and schist and dip to the southeast from 10 ft to 40 ft per mile.The normal regional dip of the Coastal Plain sediments is toward the southeast at about 8 ft to 30 ft per mile, the greater dips being in the deeper strata.Only one earthquake with intensity of V or greater has ever been recorded within 50 miles of the site. In 1959, an earthquake with intensity of V-VI (Modified Mercalli Scale) occurred about 15 miles from the site in the vicinity of McBee, SC. No permanent effects of this shock are noted in the literature or in a geologic reconnaissance, although it is presumed to have been felt at the location of the site. It is estimated that this shock had a magnitude no greater than 4.5 with an epicentral acceleration of well under 0.10 g.On the basis of the historical data, it is expected that the site area could experience a shock on the order of the 1959 McBee shock once during the life of the plant. A Magnitude 4.5 earthquake with an epicentral distance of less than ten miles was selected as the design earthquake. | ||
Although the probable ground acceleration for this earthquake would be 0.07 g | Although the probable ground acceleration for this earthquake would be 0.07 g to 0.09 g, a conservative value of 0.1 g is used for the Operational Basis Earthquake (OBE). An SSE with a maximum ground acceleration of 0.2 g was selected to provide an adequate margin of safety. | ||
Seismic Hazard and Screening | Seismic Hazard and Screening Report H.B. Robinson Steam Electric Plant (HBRSEP) Page 3 of 30 2.1 Regional and Local Geology Regional Geoloqgy In South Carolina, the Coastal Plain is composed of largely unconsolidated sediments which overlie a slightly sloping surface of crystalline rock. These crystallines are of Precambrian and early Paleozoic age with subordinate sandstones and intrusive diorities of Triassic age. Triassic sediments have been faulted into the ancient crystallines. | ||
Page 3 of | Faulted Triassic basins are evident in the Piedmont province and deep wells have located Triassic rocks in widely divergent areas beneath the Coastal Plain. Overlying the Precambrian, Paleozoic, and Triassic rocks, are the sediments of the Coastal Plain. These sediments are composed of sands, gravels, clays, shales, and limestones which range in age from Cretaceous to Pleistocene. | ||
Faulted Triassic basins are evident | The Coastal Plain itself is divided into the upper Coastal Plain and the lower Coastal Plain by what has been termed the Orangeburg Scarp, an erosional feature representing a shoreline formed during Miocene times. The elevation of the Upper Coastal Plain ranges from approximately 210 ft above Mean Sea Level, (MSL) at the Orangeburg Scarp, and 450 ft to 500 ft above MSL, at the Fall Zone. The Upper Coastal Plain is the outcrop zone of the Tuscaloosa (Middendorf) | ||
The Coastal Plain itself is divided into the upper Coastal Plain and the lower Coastal Plain | Formation of late Cretaceous age, but most of the area is blanketed by more recent alluvial deposits of sand and gravel. The elevation of the Lower Coastal Plain ranges from approximately 210 ft above MSL, at the Orangeburg Scarp to sea level at the coast. The major structural features of the region include Triassic grabens (downfaulted basins) and the Cape Fear Arch, a basement ridge which trends southeastward from the Fall Line to the Atlantic Coast just northeast of the North Carolina-South Carolina boundary. | ||
Formation of late Cretaceous age, but most of the area is blanketed by | The Cape Fear Arch has caused the overlying Coastal Plain sediments to dip away from its structure, thereby modifying the normal regional dips on its flanks.Local Geoloqy The surficial materials at the HBRSEP site are recent sands or soils developed from the Middendorf. | ||
The Cape Fear Arch | Because of the high quartz content of the sands and the climatic environment, the surficial soils may not weather sufficiently to differ considerably from the parent material. | ||
Because of the high quartz content of the sands and the climatic environment, | From an engineering standpoint, the difference is minor.The subsurface materials encountered in the test holes drilled at the site are completely consistent with recent alluvium and Middendorf Formations encountered throughout the vicinity.Discontinuities within the strata are sedimentary and no structural deformation is apparent in the Middendorf Formation in the site area.Triassic basins are known in the area; however, it is believed that the likelihood of a Triassic basin at the site is quite small. The basement rock at the site is considered to be Piedmont crystalline since the results of the seismic surveys indicate a high velocity material at a depth consistent with the depth of Piedmont crystallinesencountered in wells in the area. | ||
Seismic Hazard and Screening Report H.B. Robinson Steam Electric Plant (HBRSEP) Page 4 of 30 The upper alluvial sands and gravels are moderately compact. Layers of compressible material occur in the upper 30 ft to 50 ft. Because of the quantity of fines in the sand and gravel, it cannot be considered free-draining material. | |||
Discontinuities within the strata are sedimentary and no structural deformation is apparent in | The underlying Middendorf contains compact, relatively incompressible sands and firm to hard clayey soils. Several strata of cemented sandstone were encountered in the borings at depths of approximately 90 ft to 100 ft.2.2 Probabilistic Seismic Hazard Analysis 2.2. 1 Probabilistic Seismic Hazard Analysis Results In accordance with the 50.54(f) letter and following the guidance in the SPID (Reference 2), a probabilistic seismic hazard analysis (PSHA) was completed using the recently developed Central and Eastern United States Seismic Source Characterization (CEUS-SSC) for Nuclear Facilities (Reference | ||
Seismic Hazard and Screening | : 4) together with the updated EPRI Ground-Motion Model (GMM) for the CEUS (Reference 5). A site-specific review of the CEUS-SSC earthquake catalog was also performed as described below, and these results are incorporated into the PSHA for the HBRSEP site. For the PSHA, a lower-bound moment magnitude of 5.0 was used, as specified in the 50.54(f) letter.Site-Specific CEUS-SSC Catalog Review A site-specific review (Reference, 13) of the CEUS-SSC catalog published in the CEUS-SSC was performed with regard to two issues: (1) identification of additional reservoir induced seismicity (RIS) earthquakes in the southeastern US and (2): locations of earthquakes in South Carolina near the time of the 1886 Charleston, SC earthquake sequence.In developing the CEUS-SSC catalog, earthquakes identified as RIS were removed from the final earthquake listing. The source for this identification in the southeastern US was the set of available Southeast US Seismic Network (SEUSSN) Bulletins. | ||
Page 4 of | The master list contained 120 earthquakes. | ||
Layers of compressible | Sixteen of these were large enough to be in the CEUS-SSC catalog. These earthquakes occurred primarily near Monticello Reservoir and Lake Keowee. These earthquakes were removed from the final (Version 7) CEUS-SSC catalog published in NUREG-2115.Additional reviews were performed of available published information to identify potential additional RIS earthquakes that are in the CEUS-SSC catalog. The basis for each of the potential RIS records was reviewed, taking into consideration the magnitude of the earthquake and depth, proximity to a reservoir, timing of the earthquake versus the filling of the reservoir, and proximity to a nuclear plant.Thirty additional RI or potentially RI earthquakes were identified in the CEUS-SSC catalog. Of these, thirteen were large enough (E[M] > 2.9) to potentially affect recurrence calculations. | ||
The underlying Middendorf contains | Some of these were identified as dependent events of other earthquakes in the catalog. After Seismic Hazard and Screening Report H.B. Robinson Steam Electric Plant (HBRSEP) Page 5 of 30 review, it was determined that all thirty RI or potentially RI earthquakes should be removed from the catalog. Table 2.2.1-1 lists the specific earthquake database records reviewed.Seven additional earthquakes in the CEUS-SSC catalog from the time period 1799 to 1888 in South Carolina were also identified as being potentially mislocated (Table 2.2.1-2). | ||
The majority of these earthquakes have locations and times that come from the USGS's earthquake catalog used for seismic hazard mapping. The primary source of the USGS catalog is the NCEER-91 catalog. The events in question have alternative locations in the SUSN catalog that place them at the location of the 1886 Charleston, SC main shock. A review was performed of the identification of these earthquakes and assignment of these locations in the development of the CEUS-SSC catalog in light of additional information in the paper by W.H. Bakun and M.G.Hopper (2004, "Magnitudes and Locations of the 1811-1812 New Madrid, Missouri, and the 1886 Charleston, South Carolina, Earthquakes," Bulletin of the Seismological Society of America, 94, 64-75) and recent information provided by Donald Stevenson and Dr. Pradeep Talwani.The review identified another potential duplicate record. Bakun and Hopper (2004) also studied the Charleston aftershock on 1886/11/5 17:20 and found a location near Charleston, but slightly inland from other locations. | |||
: 4) together with the updated EPRI Ground-Motion Model (GMM) for | |||
In developing the CEUS-SSC | |||
The source for this identification in the southeastern US was the set | |||
Bulletins. | |||
The master list contained | |||
Sixteen of these were large enough to be in the CEUS-SSC catalog. | |||
The basis for each of | |||
Some of these were identified as dependent events of other earthquakes in the catalog. | |||
After Seismic Hazard and Screening | |||
Page 5 of | |||
Table 2.2.1-1 lists the specific earthquake database records reviewed. | |||
Seven additional earthquakes in the CEUS-SSC catalog from the time period 1799 to 1888 | |||
The | |||
The primary source of the USGS catalog is the NCEER- | |||
The events in question have alternative locations in the SUSN catalog that place | |||
Bulletin of the Seismological Society | |||
Talwani and Sharma (1999) also concluded that this earthquake occurred at a slightly different location than other Charleston aftershocks. | Talwani and Sharma (1999) also concluded that this earthquake occurred at a slightly different location than other Charleston aftershocks. | ||
This earthquake appears in the CEUS-SSC catalog as TMP02071. | This earthquake appears in the CEUS-SSC catalog as TMP02071. | ||
There is also an event TMP02072 that | There is also an event TMP02072 that is listed in the USGS catalog with time 12:25 with a location to the northwest of Charleston. | ||
Both events were identified as Charleston aftershocks in the declustering, but the timing suggests that they may be duplicates. | |||
The recommendation was to remove TMP02072 and use | The recommendation was to remove TMP02072 and use the magnitude and location given in Bakun and Hopper for TMP02071.An additional review was performed of earthquake locations provided by Seeber and Armbruster (1987). These locations and size assessments were incorporated into the NCEER-91 catalog and then into the USGS catalog used as the primary source for the CEUS-SSC catalog. The original Seeber and Armbruster (1987) listing was also incorporated into the CEUS-SSC catalog, along with their listed values of felt area. During the review, the classification of nine additional earthquakes at locations distance from Charleston significant to hazard (EtM]>2.9) were changed from dependent to independent. | ||
An additional review was performed of earthquake locations provided by Seeber | Previously, these earthquakes had been classified as dependent earthquakes in clusters associated with the earthquakes identified above. The information for each of these earthquakes was reviewed, including additional information provided by Stevenson and Talwani.Table 2.2.1-3 summarizes the assessment of the larger events in the CEUS-SSC catalog located at sufficient distance from Charleston to not be identified as aftershocks of the 1886/09/01 main shock. | ||
The original Seeber and Armbruster (1987) listing was also incorporated into | Seismic Hazard and Screening Report H.B. Robinson Steam Electric Plant (HBRSEP)Page 6 of 30 Table 2.2.1-1 Summary of RIS Earthquake Review Comment I TMPID yr mo Dy hr mn sec lat Ion depth E[M] Disposition TMP07012 1969 12 13 10 19 29.7 35.04 -82.85 6 3.46 Retain as non RIS TMP07159 1971 7 13 11 42 26 34.8 -83 n/a 3.63 Possible RIS........................................ | ||
Previously, | |||
Seismic Hazard and Screening | |||
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Line 183: | Line 141: | ||
....... .. ............. | ....... .. ............. | ||
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Retain as | Retain as non TMP07565 1974 8 2 8 52 11.1 33.91 -82.53 4 3.91 Ris RIS TMP08078 1975 11 25 15 17 34.8 34.93 -82.9 10* 3.21 RIS TMP08787 1977 9 7 14 41 32.7 34.982 -82.927 n/a 2.77 RIS TMP08971 1978 1 25 8 29 39 34.301 -81.234 5** 2.6 RIS TMP09354 1978 8 27 10 23 8 34.313 -81.337 2 2.93 RIS TMP08998 1978 2 10 20 23 38.7 34.343 -81.348 1 2.77 Possible RIS TMP08999 1978 2 11 0 19 0,7 34,343 -81.35 3 2 77 Possible RIS TMP09000 1978 2 11 5 19 0.2 34.346 -81.349 1 2.93 Possible RIS TMP09006 1978 2 14 12 45 72 34.342 -81.346 2 2.77 Possible RIS.................................. | ||
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....... ... .... ....... ... ..................... | ....... ... .... ....... ... ..................... | ||
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TMP09014 1978 2 16 2 14 33.4 34.332 -81.362 2 2.85 Possible | TMP09014 1978 2 16 2 14 33.4 34.332 -81.362 2 2.85 Possible RIS TMP09023 1978 2 22 7 13 25.1 34.327 -81.35 1 2.85 Possible RIS TMP09024 1978 2 22 12 13 24.3 34.339 -81.35 1 -3.00 Possible RIS TMP09002 1978 2 22 13 4 59.2 34.356 -81.352 0 2 .77 Possible RIS 1MP09027 1978 2 24 7 34 10.5 34.334 -81.348 1 2.93 Possible RIS TMP09029 1978 2 25 4 2 42.7 34.345 -81.351 1 2.77 Possible RIS TMP09031 1978 2 26 6 52 35.4 34.315 -81.297 1 2.85 Possible RIS TMP09032 1978 2 26 11 52 33 34.391 -81.361 1 3.00 Possible RIS........ ................................ | ||
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Line 215: | Line 169: | ||
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TMP09033 1978 2 26 18 17 48.8 34.321 -81.348 0 3.08 Possible RIS........ | TMP09033 1978 2 26 18 17 48.8 34.321 -81.348 0 3.08 Possible RIS........ ....... ....................... | ||
....... ....................... | |||
............ | ............ | ||
...... ..... * ........ | ...... ..... * ........ ..... b ......... | ||
..... b ......... | .. ......... ...... b ......... | ||
.. ......... | ..... d ........ ........ .... ....... .......... | ||
...... b ......... | |||
..... d ........ | |||
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I... ... 4 ........................... | I... ... 4 ........................... | ||
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n......................................................... | n......................................................... | ||
TMP09343 1978 8 24 10 23 7.6 34.311 -81.341 2 2.85 Possible | TMP09343 1978 8 24 10 23 7.6 34.311 -81.341 2 2.85 Possible RIS TMP09355 1978 8 27 10 23 8 34.313 -81.337 7 2.77 Possible RIS TMP09460 1978 10 27 16 27 18.1 34.302 -81.326 2 3.08 RIS TMP09518 1978 11 24 11 54 40.9 34.296 -81.347 1 2.85 Possible RIS TMP10034 1979 8 26 1 31 45 34.916 -82.956 1 3.64 RIS TMP39374 1979 10 8 8 54 19.4 34.31 -81.33 2 2.85 RIS.... ............................. | ||
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Line 244: | Line 194: | ||
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TMP10506 1980 7 29 1 10 22.7 34.351 -81.364 1 3.31 Possible | TMP10506 1980 7 29 1 10 22.7 34.351 -81.364 1 3.31 Possible RIS TMP16282 1988 1 27 22 5 42.9 34.189 -82.75 6.1 2.32 RIS* depth 17 km in RANDJ** depth 1 km in Stover & Coffman Seismic Hazard and Screening Report H.B. Robinson Steam Electric Plant (HBRSEP)Page 7 of 30 Table 2.2.1-2 Potential Charleston SC Area Aftershocks from CEUS-SSC Catalog Source of Catalog TMPID yr Mo Dy hr mn sec Lat Ion E[M] Location USGSnd_000145 TMP00331 1799 4 11 8 20 0 33.95 -80.18 4.68 Revised by Jeff Munsey of TVA based on Bakun and Hopper Method | ||
..... ...... ............. | ..... ...... ............. | ||
..... .... ...... ......... | ..... .... ...... ......... | ||
Line 261: | Line 211: | ||
.. .. ................. | .. .. ................. | ||
... ................ | ... ................ | ||
I ............. .......... | I ............. .......... .i ................... .e~ ~ ; Y B 6 i; ............................. | ||
.i ................... | |||
.e~ ~ ; Y B 6 i; ............................. | |||
TMP01731 1886 9 1 6 0 0 33.91 -82.02 4.54 SeebArm87...000014 TMP01739 1886 9 1 9 45 0 34.3 -82.86 4.17 USGSnd_000771 | TMP01731 1886 9 1 6 0 0 33.91 -82.02 4.54 SeebArm87...000014 TMP01739 1886 9 1 9 45 0 34.3 -82.86 4.17 USGSnd_000771 | ||
........ | ........ .....f .......... | ||
.....f .......... | .........: 8 .i- ........ ............. | ||
......... | |||
: 8 .i- ........ ............. | |||
.' ............ | .' ............ | ||
.. .............. | .. .............. | ||
Line 274: | Line 220: | ||
_:. i .......... | _:. i .......... | ||
:................... | :................... | ||
... ................ | ... ................ -G n ; _ -- .............................................. | ||
-G n ; _ -- .............................................. | |||
TMP02019 1886 10 22 5 0 0 34.71 -81.66 4.13 USGSnd_000805 | TMP02019 1886 10 22 5 0 0 34.71 -81.66 4.13 USGSnd_000805 | ||
.....i ............... | .....i ............... | ||
I ............ | I ............ | ||
"....... | "....... ........ .2 -i , " | ||
........ .2 -i , " | |||
...... ... ...... .-.. " .... .... ....... ...... ...... ......... | ...... ... ...... .-.. " .... .... ....... ...... ...... ......... | ||
;I .......... | ;I .......... | ||
Line 295: | Line 239: | ||
7 -... ...-4 -* * *.......... | 7 -... ...-4 -* * *.......... | ||
............. | ............. | ||
-TMP02360 1888 1 12 9 55 0 34.18 -80.17 4.33 USGSnd_000860 Table 2.2.1- | -TMP02360 1888 1 12 9 55 0 34.18 -80.17 4.33 USGSnd_000860 Table 2.2.1-3 Summary of Events Affected by the Charleston Aftershock Review TMPID yr Mo Dy Hr Mn sec lat Ion Comment / Disposition TMP00331 1799 4 11 8 20 0 33.95 -80.18 Retainasis | ||
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....I........................ | ....I........................ | ||
Line 305: | Line 249: | ||
................... | ................... | ||
I....................... | I....................... | ||
.................... e i ~ :a i d ' a n i i a -........ | .................... e i ~ :a i d ' a n i i a -........ ...TMP01089 1860 1 19 23 0 0 33.68 -80.57 Mo o 10 E[M] on 10.............. | ||
...TMP01089 1860 1 19 23 0 0 33.68 -80.57 Mo o | |||
............... | ............... | ||
....... .... ............... | ....... .... ............... | ||
Line 314: | Line 257: | ||
I ........... | I ........... | ||
......... | ......... | ||
........ | ........ ...... ................ | ||
...... ................ | ........ ................................... | ||
........ | |||
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.................................. | .................................. | ||
Event removed from catalog | Event removed from catalog as a duplicate of TMP01 732.TMP01731 1886 9 1 6 0 0 33.91 -82.02 Location and magnitude of TMP01732.do not require modification Event removed from catalog as a duplicate of TMP01738.TMP01739 1886 9 1 14* 45 0 34.04 -82.9 Location and magnitude of TMP01738 do not require modification | ||
TMP01739 1886 9 1 14* 45 0 34.04 -82.9 Location and magnitude | |||
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......... | ......... | ||
........ | ........ ....... ..... .............. | ||
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.. .. ............... | .. .. ............... | ||
Line 333: | Line 272: | ||
.... ......TMP01942 1886 9 28 3 0 0 34.7 -81.62 Consider as a false event.................................. | .... ......TMP01942 1886 9 28 3 0 0 34.7 -81.62 Consider as a false event.................................. | ||
... ......... | ... ......... | ||
....... ........ | ....... ........ .... .. ......... | ||
.... .. ......... | |||
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Line 343: | Line 281: | ||
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.....TMP02002 1886 10 12 11 0 I0 34.14 -81.33 Not use reported felt area, | .....TMP02002 1886 10 12 11 0 I0 34.14 -81.33 Not use reported felt area, event 1 0 0becomes < E[M] 2.9 TMP02019 1886 10 22. 5 0 0 34.71 -81.66 Event removed from catalog as a duplicate of TMP02023 Magnitude taken from Bakun TMP02023 1886 10 22 10 20 32.9 -80 and Hopper (2004)............................ | ||
< E[M] 2. | |||
.. , .;... ..... ..... ... ........... | .. , .;... ..... ..... ... ........... | ||
.. ... ... ................................ | .. ... ... ................................ | ||
Line 350: | Line 287: | ||
.. ............ | .. ............ | ||
...d .H.° P r..2.. ° °... t)..... ......................................... | ...d .H.° P r..2.. ° °... t)..... ......................................... | ||
TMP02024 1886 10 22 10* 25 I , 33.69 -81 Event removed from catalog | TMP02024 1886 10 22 10* 25 I , 33.69 -81 Event removed from catalog as TMP0024 188 ' 10 2 1* 2 .3.69 -81 a duplicate of TM P02023.. ...... .. ............... | ||
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...... .. ....... .................... | ...... .. ....... .................... | ||
....... ......d.....of T M 0 2 | ....... ......d.....of T M 0 2 2 0 33.87 Location moved to Charleston, TMP02025 1886 10 22 14 45 0 33.87 -81.01 magnitude taken from Bakun... .. .. ..... ...... .. .. .. .... ...... ..... .. ... .. ..... .. .. ... .. ....... .. ......... | ||
... ....... ......... | ... ....... ......... | ||
....... .. .. ... ....... .. ....... .................. | ....... .. .. ... ....... .. ....... .................. | ||
Seismic Hazard and Screening | Seismic Hazard and Screening Report H.B. Robinson Steam Electric Plant (HBRSEP)Page 8 of 30 TMPID yr Mo Dy Hr Mn sec lat Ion Comment / Disposition and Hopper (2004)TMP02068 1886 11 5 5 0 0 33.38 -82.49 Not use reported felt area, event becomes < E[M] 2.9 TMP02071 1886 11 5 17 20 0 32.9 -80 Magnitude taken from Bakun and Hopper (2004)TMP02072 1886 11 5 12 25 33.4 -80.42 Event removed from catalog as a duplicate of TMP02071.TMP02134 1886 12 8 10 25 0 34.039 -80.886 Revise 10 from 4.5 to 4 TMP02136 1886 12 11 21 0 0 34.18 -82.06 Retain as is TMP02173 1887 1 12 11 0 0 34.35 -82.42 Retain as less than E[M] 2.9, remove felt area TMP02210 1887 3 4 10 0 0 33.74 -81.5 Not use reported felt area, event becomes < E[M] 2.9 TMP02360 1888 1 12 9 55 0 34.18 -80.17 Event removed from catalog as a duplicate of TMP39326.TMP02393 1888 4 5 0 0 0 34.21 -81.534 Retain, reduce to 10 4, E[M] less than 2.9 TMP02423 1888 8 15 23 30 0 34,37 -81.08 Retain as is* Change in hour.Probabilistic Seismic Hazard Analysis For the PSHA, the CEUS-SSC (Reference | ||
TMP02134 1886 12 8 10 25 0 34.039 -80.886 Revise 10 from 4.5 to | : 4) background seismic sources out to a distance of 400 miles (640 kin) around the site were included. | ||
TMP02393 1888 4 5 0 0 0 34.21 -81.534 Retain, reduce to 10 4, E[M] | |||
: 4) background seismic sources out to a distance | |||
This distance exceeds the 200 mile (320 km)recommendation contained in Reg. Guide 1.208 (Reference | This distance exceeds the 200 mile (320 km)recommendation contained in Reg. Guide 1.208 (Reference | ||
: 6) and was chosen | : 6) and was chosen for completeness. | ||
Background sources included in this site analysis are the following: | Background sources included in this site analysis are the following: | ||
: 1. Atlantic Highly Extended Crust (AHEX)2. Extended Continental Crust-Atlantic Margin (ECC.AM)3. Extended Continental Crust-Gulf Coast (ECC_GC)4. Mesozoic and younger extended prior -narrow (MESE-N)5. Mesozoic and younger extended prior -wide (MESE-W)6. Midcontinent-Craton alternative A (MIDCA)7. Midcontinent-Craton alternative B (MIDCB)8. Midcontinent-Craton alternative C (MIDCC)9. Midcontinent-Craton alternative D (MIDCD)10. Non-Mesozoic and younger extended prior -narrow (NMESE-N) | : 1. Atlantic Highly Extended Crust (AHEX)2. Extended Continental Crust-Atlantic Margin (ECC.AM)3. Extended Continental Crust-Gulf Coast (ECC_GC)4. Mesozoic and younger extended prior -narrow (MESE-N)5. Mesozoic and younger extended prior -wide (MESE-W)6. Midcontinent-Craton alternative A (MIDCA)7. Midcontinent-Craton alternative B (MIDCB)8. Midcontinent-Craton alternative C (MIDCC)9. Midcontinent-Craton alternative D (MIDCD)10. Non-Mesozoic and younger extended prior -narrow (NMESE-N)11. Non-Mesozoic and younger extended prior -wide (NMESE-W)12. Paleozoic Extended Crust narrow (PEZN)13. Paleozoic Extended Crust wide (PEZW)14. Reelfoot Rift including the Rough Creek Graben (RR-RCG)15. Study region (STUDYR) | ||
Seismic Hazard and Screening Report H.B. Robinson Steam Electric Plant (HBRSEP) Page 9 of 30 For sources of large magnitude earthquakes, designated Repeated Large Magnitude Earthquake (RLME) sources in CEUS-SSC (Reference 4), the following sources lie within 1,000 km of the site and were included in the analysis: 1. Charleston | |||
: 2. Commerce 3. Eastern Rift Margin Fault northern segment (ERM-N)4. Eastern Rift Margin Fault southern segment (ERM-S)5. Marianna 6. New Madrid Fault System (NMFS)7. Wabash Valley For each of the above background and RLME sources, the mid-continent version of the updated CEUS EPRI GMM was used.2.2.2 Base Rock Seismic Hazard Curves Consistent with the SPID (Reference 2), base rock seismic hazard curves are not provided as the site amplification approach referred to as Method 3 has been used. Seismic hazard curves are shown below in Section 3 at the SSE control point elevation. | |||
Seismic Hazard and Screening | 2.3 Site Response Evaluation Following the guidance contained in Seismic Enclosure 1 of the 3/12/2012 50.54(f) Request for Information and in the SPID (CEUS-SSC, 2013a) for nuclear power plant sites that are not sited on hard rock (defined as 2.83 km/sec), a site response analysis was performed for HBRSEP.2.3.1 Description of Subsurface Material The HBRSEP is located in the Coastal Plain Physiographic Province of South Carolina. | ||
Page 9 of | The general site conditions consist of about 50 ft (15.2 m) of recent alluvium overlying about 400 ft (122 m) of stiff sands, sandstones, and mudstones. | ||
: 1. Charleston | Precambrian basement consisting of Piedmont crystalline rocks lie below the sedimentary section (Reference 16).Table 2.3.1-1 shows the recommended geotechnical properties for the site. | ||
: 2. | Seismic Hazard and Screening Report H.B. Robinson Steam Electric Plant (HBRSEP) Page 10 of 30 Table 2.3.1-1 (Reference 16)Summary of Site Geotechnical Profile for HBRSEP Depth* Shear Compressional Assumed Range Soil/Rock Density Wave Wave Velocity Poisson's (feet) Description (pcf) Velocity (fps) Ratio (fps)Recent Alluvium 0' to 56' RScnt Alluvium 125 1000** 1500 0.33 (Sand and Gravel)Cretaceous Middendorf 56' to 460' (Sands, Silty and Sandy 130 3600 7200 0.33 Clay, Sandstone and Mudstone)Pre-Cambrian Crystalline | ||
2.3 Site Response Evaluation Following the guidance contained in Seismic Enclosure 1 of the 3/12/2012 50.54(f) | > 460' (Granite, Gneiss, Phyllite 170 11200 17500 0.15 Schist)*Measured from EL. 226 ft."The original soil profile data obtained from Figure 2.5.1-2 of the HBR2 Updated FSAR has been adjusted based on recommendations of MACTEC in EC54720-ZOO Attachment A. Figure 2.5.1-2 had a shear wave velocity of 750 fps for the first 30ft of soil (measured from EL. 226 ft);whereas, MACTEC suggested an adjusted value of 1000 fps for the first 70ft of soil (measured from EL. 240 ft). All other soil profile data in Table 2 remains the same as given in Figure 2.5.1-2 of the Updated FSAR.The following description of the general geology at the site is taken directly from URS (Reference 16): "The surficial materials at the HBRSEP site are recent sands or soils developed from the Middendorf. | ||
Request | Because of the high quartz content of the sands and the climatic environment, the surf icial soils may not weather sufficiently to differ considerably from the parent material.Thus, it is nearly impossible to distinguish the recent alluvial soils from the parent Middendorf sand since both the alluvial and weathered soils are derived from the Middendorf. | ||
a site response analysis was performed for HBRSEP.2.3.1 Description of Subsurface | |||
Precambrian basement consisting | |||
Seismic Hazard and Screening | |||
Page 10 of | |||
Pre-Cambrian Crystalline | |||
> 460' (Granite, Gneiss, Phyllite 170 11200 17500 0. | |||
Because of the high quartz content of the sands and the climatic environment, | |||
Thus, it is nearly impossible to distinguish the recent alluvial soils from the | |||
Only their manner of placement would be different. | Only their manner of placement would be different. | ||
From an engineering standpoint, the difference is minor.The subsurface materials encountered in the test holes drilled at the site are completely consistent with recent alluvium and Middendorf Formations encountered throughout | From an engineering standpoint, the difference is minor.The subsurface materials encountered in the test holes drilled at the site are completely consistent with recent alluvium and Middendorf Formations encountered throughout the vicinity. | ||
Discontinuities within the strata are sedimentary and no structural deformation is apparent in the Middendorf Formation in the site area.The Middendorf is about 400 ft thick and overlies an eroded, slightly sloping surface | Discontinuities within the strata are sedimentary and no structural deformation is apparent in the Middendorf Formation in the site area.The Middendorf is about 400 ft thick and overlies an eroded, slightly sloping surface of Piedmont crystallines that may be somewhat weathered near the surface.Triassic basins are known in the area; however, it is believed that the likelihood of a Triassic basin at the site is quite small. The basement rock at the site is considered to Seismic Hazard and Screening Report H.B. Robinson Steam Electric Plant (HBRSEP) Page 11 of 30 be Piedmont crystalline since the results of the seismic surveys indicate a high velocity material at a depth consistent with the depth of Piedmont crystallines encountered in wells in the area.In general, the upper alluvial sands and gravels are moderately compact. Layers of compressible material occur in the upper 30 to 50 ft. Because of the quantity of fines in the sand and gravel, it could not be considered free-draining material. | ||
Page 11 of | The underlying Middendorf contains generally compact relatively incompressible sands and firm to hard clayey soils. Several strata of cemented sandstone were encountered in the borings at depths of roughly 90 to 100 ft.From a geological standpoint, the Middendorf is considered to be an unconsolidated formation. | ||
Layers | From an engineering point of view, however, the materials are firm and compact and would provide good foundation support for the proposed construction. | ||
The underlying Middendorf contains generally compact relatively incompressible sands and firm to | The materials range in texture from a hard or compact soil to a soft rock." 2.3.2 Development of Base Case Profiles and Nonlinear Material Properties Table 2.3.1-1 shows the recommended shear-wave velocities and unit weights verses depth for the profile. Based on Table 2.3.1-1 and the location of the SSE at surface (Reference 16), the profile consists of 460 ft (140.2 m) of soils and soft rock overlying hard crystalline basement rock.Shear-wave velocities for the profile were based on measurements of compressional-wave velocities (Reference 16), likely through refraction surveys, and assumed Poisson ratios. More recent downhole testing at the nearby ISFSI revised the surf icial alluvium shear-wave velocity from 750 ft/s (228.6 m/s) to 1,000 ft/s (304.8 m/s) (Table 2.3.1-1) and confirmed the deeper shear-wave velocities (Reference 16).For the stiff soils and soft rock of the Cretaceous Middendorf Formation (Table 2.3.1-1), a depth dependent shear-wave velocity gradient, rather than a constant velocity or constant gradient over a 400 ft depth range, was assumed to more accurately, reflect in-situ conditions. | ||
From an engineering point of view, however, the materials are firm | To model a representative velocity gradient for the Middendorf Formation, a 760 m/s (Vs (30 m)) generic profile (Reference | ||
: 2) was adopted and adjusted to reflect the average shear-wave velocity for the Middendorf Formation as specified in Table 2.3.1-1 (Reference 16). The adopted gradient profile is shown in Figure 2.3.2-1.Based on the specified shear-wave velocities, reflecting measured compressional-wave velocities and assumed Poisson ratios, a scale factor of 1.57 was adopted to reflect upper and lower range base-cases. | |||
Based on Table 2.3.1-1 and the location of the SSE at surface (Reference 16), | The scale factor of 1.57 reflects a cr.1 of about 0.35 based on the SPID (Reference | ||
: 2) 10& and 9 0 th fractiles which implies a 1.28 scale factor on op.Using the shear-wave velocities specified in Table 2.3.2-1, three base-profiles were developed using the scale factor of 1.57. The specified shear-wave velocities were taken as the mean or Seismic Hazard and Screening Report H.B. Robinson Steam Electric Plant (HBRSEP)Page 12 of 30 best estimate base-case profile (P1) with lower and upper range base-cases profiles P2 and P3 respectively. | |||
a | The three base-case profiles P1, P2, and P3, have a mean depth below the SSE of 460 ft (140.2 m) to hard reference rock, randomized | ||
+/- 93 ft (+/- 28.4 m). The base-case profiles (P1, P2, and P3) are shown in Figure 2.3.2-1 and listed in Table 2.3.2-2. The depth randomization reflects +/- 20% of the depth and was based on both borehole and refraction confirmation as well as to provide a realistic broadening of the fundamental resonance rather than reflect actual random variations to basement shear-wave velocities across a footprint. | |||
To | Vs profiles for Robinson Site Vs (ft/sec)0 1000 2000 3000 4000 5000 6000 7000 8000 9000 10000 0 so 50 100 150 200 1250 is300 350 400 450 500-Profile 1-Profile 2~ 250-Profile 3 Figure 2.3.2-1. Shear-wave velocity profiles for the HBRSEP site.Table 2.3.2-2 Layer thicknesses, depths, and shear-wave velocities (Vs) for 3 profiles, the HBRSEP site Profile 1 Profile 2 Profile 3 thickness(ft) depth (ft) Vs(ftts) thickness(ft) depth (ft) Vs(ft/s) thickness(ft) depth (ft) Vs(if/s)0 1000 0 640 0 1570 5.6 5.6 1000 5.6 5.6 640 5.6 5.6 1570 5.6 11.2 1000 5.6 11.2 640 5.6 11.2 1570 5.6 16.8 1000 5.6 16.8 640 5.6 16.8 1570 5.6 22.4 1000 5.6 22.4 640 5.6 22.4 1570 5.6 28.1 1000 5.6 28.1 640 5.6 28.1 1570 5.6 33.7 1000 5.6 33.7 640 5.6 33.7 1570 5.6 39.3 1000 5.6 39.3 640 5.6 39.3 1570 5.6 44.9 1000 5.6 44.9 640 5.6 44.9 1570 5.6 50.5 1000 5.6 50.5 640 5.6 50.5 1570 5.6 56.1 1000 5.6 56.1 640 5.6 56.1 1570 Seismic Hazard and Screening Report H.B. Robinson Steam Electric Plant (HBRSEP)Page 13 of 30 5.0 61.1 1566 5.0 61.1 1002 5.0 61.1 2458 4.0 65.1 1706 4.0 65.1 1092 4.0 65.1 2679 7.4 72.5 1914 7.4 72.5 1225 7.4 72.5 3005 7.5 80.1 2110 7.5 80.1 1350 7.5 80.1 3312 11.0 91.0 2312 11.0 91.0 1480 11.0 91.0 3630 15.0 106.0 2531 15.0 106.0 1620 15.0 106.0 3974 18.0 124.0 2815 18.0 124.0 1802 18.0 124.0 4420 22.0 146.1 3100 22.0 146.1 1984 22.0 146.1 4867 25.0 171.1 3380 25.0 171.1 2163 25.0 171.1 5306 33.0 204.1 3720 33.0 204.1 2381 33.0 204.1 5840 42.0 246.1 4150 42.0 246.1 2656 42.0 246.1 6515 35.0 281.1 4520 35.0 281.1 2893 35.0 281.1 7096 35.0 316.1 4520 35.0 316.1 2893 35.0 316.1 7096 33.3 349.4 4780 33.3 349.4 3059 33.3 349.4 7504 33.3 382.7 4780 33.3 382.7 3059 33.3 382.7 7504 33.3 416.1 4780 33.3 416.1 3059 33.3 416.1 7504 44.0 460.1 4780 44.0 460.1 3059 44.0 460.1 7504 3280.8 3740.9 9285 3280.8 3740.9 9285 3280.8 3740.9 9285 2.3.2.2 Shear Modulus and Damping Curves No site-specific nonlinear dynamic material properties were determined for the soil and soft rock materials in the initial siting of the HBRSEP. For both the shallow recent alluvium and the stiff sands and soft rock of the Middendorf Formation, EPRI cohesionless soil and Peninsular Range G/Gm,, and hysteretic damping curves we considered appropriate (Reference 2). To more adequately accommodate epistemic uncertainty in nonlinear dynamic material properties, since the relatively high shear-wave velocities coupled with Peninsular Range modulus reduction and hysteretic damping curves results in largely linear response in the Middendorf Formation, a third case comprising a combination of EPRI soil and EPRI rock curves was added. The third case (model M3) consisted of EPRI soil curves for the shallow recent alluvium combined with EPRI rock curves for the Middendorf Formation. | ||
: 2) was adopted and adjusted to reflect the average shear-wave velocity | The three cases of nonlinear dynamic material properties was considered to reflect a realistic range in response from largely linear with Peninsular Range curves throughout to significant nonlinearity with the use of EPRI (soil and rock) curves throughout. | ||
The scale factor of 1.57 reflects a cr.1 of about 0.35 based on | The three combinations of EPRI and Peninsular Range G/Gmrx and hysteretic damping curves with a depth distribution based on assuming the Middendorf Formation behaves either as all soil or all soft rock, were considered to equally reflect in-situ conditions (Table 2.3.2-3).2.3.2.3 Kappa For the HBRSEP profile of about 460 ft (140.2 m) of soil and soft rock over hard reference rock, the kappa value of 0.006s for hard rock (Reference | ||
: 2) 10& and | : 2) was combined with the low strain Seismic Hazard and Screening Report H.B. Robinson Steam Electric Plant (HBRSEP) Page 14 of 30 damping in the hysteretic damping curves to give the values listed in Table 2.3.2-3. The low strain kappa values range from 0.008s for the stiffest profile (P3) and EPRI or Peninsular Range curves to 0.019s for the softest profile (P2) combined with EPRI soil and rock curves (Table 2.3.2-3). | ||
The three base-case profiles P1, P2, and P3, have a mean depth below the | The full epistemic uncertainty in overall profile damping has contributions from kappa at low strain in the soil and soft rock but also the wide range in hysteretic damping curves at higher loading levels of significance to design.Table 2.3.2-3 Kappa Values and Weights Used for Site Response Analyses Kaploa(s)Velocity Profile M1, M2 M3 P1 0.009 0.014 P2 0.011 0.019 P3 0.008 0.011 Weights M P1 0.4 P2 0.3 P3 0.3 G/Gm, and Hysteretic Damping Curves M1 0.3 F t'M2 0.3 M3 0.3 2.3.3 Randomization of Base Case Profiles To account for the aleatory variability in dynamic material properties that is expected to occur across a site at the scale of a typical nuclear facility, variability in the assumed shear-wave velocity profiles has been incorporated in the site response calculations. | ||
+/- 93 ft (+/- 28.4 m). The base-case profiles (P1, P2, and P3) are shown in Figure 2.3.2-1 and listed in Table 2.3.2-2. | For the HBRSEP site, random shear wave velocity profiles were developed from the base case profiles shown in Figure 2.3.2-1. Consistent with the discussion in Appendix B of the SPID (Reference 2), the velocity randomization procedure made use of random field models which describe the statistical correlation between layering and shear wave velocity. | ||
The | The default randomization parameters developed in Toro (1997) for USGS "A" site conditions were used for this site.Thirty random velocity profiles were generated for each base case profile. These random velocity profiles were generated using a natural log standard deviation of 0.25 over the upper 50 ft and 0.15 below that depth. As specified in the SPID (Reference 2), correlation of shear wave velocity between layers was modeled using the footprint correlation model. In the correlation model, a limit of +/- 2 standard deviations about the median value in each layer was assumed for the limits on random velocity fluctuations. | ||
+/- 20% of the depth and was based on both borehole and refraction confirmation as well as to provide a realistic broadening of the fundamental resonance | Seismic Hazard and Screening Report H.B. Robinson Steam Electric Plant (HBRSEP) Page 15 of 30 2.3.4 Input Spectra Consistent with the guidance in Appendix B of the SPID (Reference 2), input Fourier amplitude spectra were defined for a single representative earthquake magnitude (M 6.5) using two different assumptions regarding the shape of the seismic source spectrum (single-corner and double-corner). | ||
Vs profiles for Robinson | |||
Shear-wave velocity profiles for the HBRSEP site.Table 2.3.2- | |||
The three cases of nonlinear dynamic | |||
The three combinations of EPRI and Peninsular Range G/Gmrx | |||
2.3.2.3 | |||
: 2) was combined with the low strain Seismic Hazard and Screening | |||
Page 14 of | |||
The | |||
The full epistemic uncertainty in overall profile damping has contributions from | |||
Velocity Profile M1, M2 | |||
For the HBRSEP site,random shear wave velocity profiles were developed from the base case profiles shown | |||
Consistent with the discussion in Appendix B of the SPID (Reference 2), | |||
The default randomization parameters developed in Toro (1997) for USGS "A" site conditions were used for this site.Thirty random velocity profiles were generated for each base case profile. | |||
These | |||
Seismic Hazard and Screening | |||
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A range of 11 different input amplitudes (median peak ground accelerations (PGA) ranging from 0.01 to 1.5 g) were used in the site response analyses. | A range of 11 different input amplitudes (median peak ground accelerations (PGA) ranging from 0.01 to 1.5 g) were used in the site response analyses. | ||
The characteristics of the seismic source and upper crustal attenuation properties assumed for the analysis of | The characteristics of the seismic source and upper crustal attenuation properties assumed for the analysis of the HBRSEP site were the same as those identified in Tables B-4, B-5, B-6 and B-7 of the SPID (Reference | ||
: 2) as appropriate for typical CEUS sites.2.3.5 Methodology To perform the site response analyses for the HBRSEP site, a random vibration theory (RVT)approach was employed. | : 2) as appropriate for typical CEUS sites.2.3.5 Methodology To perform the site response analyses for the HBRSEP site, a random vibration theory (RVT)approach was employed. | ||
This process utilizes a simple, efficient approach for computing site-specific amplification functions and is consistent with existing NRC guidance and the SPID(Reference 2). The guidance contained in Appendix B of the SPID (Reference | This process utilizes a simple, efficient approach for computing site-specific amplification functions and is consistent with existing NRC guidance and the SPID (Reference 2). The guidance contained in Appendix B of the SPID (Reference | ||
: 2) | : 2) on incorporating epistemic uncertainty in shear-wave velocities, kappa, non-linear dynamic properties and source spectra for plants with limited at-site information was followed for the HBRSEP site.2.3.6 Amplification Functions The results of the site response analysis consist of amplification factors (5% damped pseudo absolute response spectra) which describe the amplification (or de-amplification) of hard reference rock motion as a function of frequency and input reference rock amplitude. | ||
The amplification factors are represented in terms of a median amplification value and an associated standard deviation (sigma) for each oscillator frequency and input rock amplitude. | |||
Consistent with the SPID (Reference | Consistent with the SPID (Reference | ||
: 2) a minimum median amplification value of 0.5 was employed in | : 2) a minimum median amplification value of 0.5 was employed in the present analysis. | ||
Figure 2.3.5-1 illustrates the median and +/- 1 standard deviation in | Figure 2.3.5-1 illustrates the median and +/- 1 standard deviation in the predicted amplification factors developed for the eleven loading levels parameterized by the median reference (hard rock) peak acceleration (0.01g to 1.50g) for profile P1 and EPRI soil G/Gm, and hysteretic damping curves. The variability in the amplification factors results from variability in shear-wave velocity, depth to hard rock, and modulus reduction and hysteretic damping curves. To illustrate the effects of nonlinearity at the HBRSEP site, Figure 2.3.5-2 shows the corresponding amplification factors developed with Peninsular Range G/Gmý, and hysteretic damping curves resulting in the most linear analyses. | ||
Finally, Figure 2.3.5-3 shows the effects of treating the shallow alluvium with EPRI soil curves and the Middendorf Formation with EPRI rock curves, reflecting the most nonlinear analyses. | |||
Seismic Hazard and Screening Report H.B. Robinson Steam Electric Plant (HBRSEP)Page 16 of 30 C -U C'-U 4"m ca: S CC INPUT MiOTION 0.01G CýINPUT MOTION 0.05G 0 INPUT MOTION 0. LOG-1 1 1 .1 1 C3 INRiT NIOTION4 0.20G I 1 1II I I I T1 INPUT MOTION INPUT 0.40G w -1 0 1a 1 Frequenci (Hz)O 2 10 1 IGO in I1 Frequency (Hz)a2 AMPLIFICATION, ROBINSON, MIPIKI M 6.5, 1 CORNER: PAGE I OF 2 Figure 2.3.5-1 .Example suite of amplification factors (5% damping pseudo absolute acceleration spectra) developed for the mean base-case profile (P1), EPRI soil modulus reduction and hysteretic damping curves (model Ml), and base-case kappa at eleven loading levels of hard rock median peak acceleration values from 0.01 g to 1.50g. M 6.5 and single-comer source model (Reference 2). | |||
Seismic Hazard and Screening | Seismic Hazard and Screening Report H.B. Robinson Steam Electric Plant (HBRSEP)Page 17 of 30 id U a-CC-i NPUT /rOTýýO Ný....3-d2o-INPUT NOTIONI.M6O 0 C3 0 0 0: 03 0,-0 INPUT MOTION M.SG INPUT MOTION' 1.25G to -1 to 0 101 Frequency (Hz)12 AMPLIFICATION, ROBINSON, MIPIKI M 6.5, 1 CORNER: PRGE 2 OF 2 Figure 2.3.5-1 .(cont.) | ||
Seismic Hazard and Screening Report H.B. Robinson Steam Electric Plant (HBRSEP)Page 18 of 30 Cl-a: C, 4j* -I~R INPUT MOTIONI 0.OMG INP UT NOTlIr ON .tLOG[INPUT' MOT IICH 0.05G C 0 INPUT rIOT ICt4 O.20G 0-aIjI.I,,.iIaIpIIuI,.iIII. | |||
Seismic Hazard and Screening | C -00 4-V-cc 7.-".f~~*'*% *~~*~*--...-INPUT (IOTICH OIOG C2 INPUT NOTIONI 0.40G 10-q to ) o (Hz1 Frequencyl ftz)1 2 10 -3 IQ 0 10 1 Frequency (Hz)10 2 AMIPLIFICATION, ROBINSON, M2PIKI M 6,5, 1 CORNER; PAGE 1 OF 2 Figure 2.3.5-2. Example suite of amplification factors (5% damping pseudo absolute acceleration spectra) developed for the mean base-case profile (P1), Peninsular Range Modulus reduction and hysteretic damping curves (model M2), and base-case kappa at eleven loading levels of hard rock median peak acceleration values from O.01g to 1.50g. M 6.5 and single-comer source model (Reference 2). | ||
Seismic Hazard and Screening Report H.B. Robinson Steam Electric Plant (HBRSEP)Page 19 of 30 C-.ill U ci 0~E a: 0 C-ci~4-, U ci 0~a: 0 C-4-i U* -. 0 0~a: a* K~\., '5-. '~S., 5 '~~5 5 -* --------~iNpur ~ori~ OSOG-S--* J,'\ 'S'55 -* -- 5-~% | |||
Seismic Hazard and Screening | * 4 S /: Ifful NOT]CII lOOt;03 0ý03 1 11- 1 111'INU NTO 0,75 INPUT M0TItN 1 .25C 0 vi-0 to U 101 Frequencgj (Hz)AMPLIFICATION, ROBINSON, M2PIK1 M 6.5, 1 CORNER; PAGE 2 OF 2 Figure 2.3.5-2.(cont.) | ||
C - | Seismic Hazard and Screening Report H.B. Robinson Steam Electric Plant (HBRSEP)Page 20 of 30 C 02 U 0.~ 0 0~C a: C-4-,'a U 0* .-. 0 0~~C 0 C aS'a U~2o 0~E a: 0 SINPUT MOTION' O0.G* *~, *-.---*'0 03 0 0 0 0)0~!NPUT MOTION0 LOAG-~ '. -~SINPUT NOTION 0,05G INPUT MiOTION4 0.20G INPUT iROTION 0.40G S2 INPUT MOTION4 0.30G I IIfll I i I B J m 1o -1 to 0 to 1 Frequency (Hz)to-, o0 10w1 Frequency (Hz)10 2 AMPLIFICATION, ROBINSON, M3PIK1 M 6.5, 1 CORNER: PAGE 1 OF 2 Figure 2.3.5-3.Example suite of amplification factors (5% damping pseudo absolute acceleration spectra) developed for the mean base-case profile (P1), EPRI soil (alluvium) and rock (Middendorf Formation) modulus reduction and hysteretic damping curves (model M3), and base-case kappa at eleven loading levels of hard rock median peak acceleration values from O.01g to 1.50g. M 6.5 and single-corner source model (Reference 2). | ||
Seismic Hazard and Screening Report H.B. Robinson Steam Electric Plant (HBRSEP)Page 21 of 30 C -0 C 0~Z C)09 L)C3-9 CI-e, cc INPUT rIOTICNi 0.50G IN~PUT MOTION E1.00GG 0}INPUT MOTICH O.75G 0S 0 C3-2 to 0 I0 1 Frequency (Hz)AMPLIFICATION, ROBINSON, M3PIK1 M 6.5, 1 CORNER; PAGE Z OF 2 Figure 2.3.5-3: (cont.) | |||
Example suite of amplification factors (5% damping pseudo absolute acceleration spectra) developed for the mean base-case profile (P1), Peninsular | Seismic Hazard and Screening Report H.B. Robinson Steam Electric Plant (HBRSEP)Page 22 of 30 2.3.7 Control Point Seismic Hazard Curves The procedure to develop probabilistic site-specific control point hazard curves used in the present analysis follows the methodology described in Section B-6.0 of the SPID (Reference 2).This procedure (referred to as Method 3) computes a site-specific control point hazard curve for a broad range of spectral accelerations given the site-specific bedrock hazard curve and site-specific estimates of soil or soft-rock response and associated uncertainties. | ||
Seismic Hazard and Screening | This process is repeated for each of the seven spectral frequencies for which ground motion equations are available. | ||
* | The dynamic response of the materials below the control point was represented by the frequency-and amplitude-dependent amplification functions (median values and standard deviations) developed and described in the previous section. The resulting control point mean hazard curves for HBRSEP are shown in Figure 2.3.7-1 for the seven spectral frequencies for which ground motion equations are defined. Tabulated values of mean and fractile seismic hazard curves and site response amplification functions are provided in Appendix A.Total Mean Soil Hazard by Spectral Frequency at Robinson 1E-2 1E-3 ----_____-25 Hz-10 Hz 1E-4--5 Hz a -PGA 0 -2.5 Hz 1E-5 ...~-1 Hz-0.5 Hz 1E-6 1E-7 0.01 0.1 1 10 Spectral acceleration (g)Figure 2.3.7-1. Control point mean hazard curves for oscillator frequencies of 0.5, 1, 2.5, 5, 10, 25 and 100 Hz at HBRSEP.2.4 Ground Motion Response Spectrum The control point hazard curves described above have been used to develop uniform hazard response spectra (UHRS) and the ground motion response spectrum (GMRS). The UHRS were obtained through linear interpolation in log-log space to estimate the spectral acceleration at each spectral frequency for the 1 E-4 and 1 E-5 per year hazard levels. Table 2.4-1 shows the UHRS and GMRS accelerations for each of the seven frequencies. | ||
I Seismic Hazard and Screening Report H.B. Robinson Steam Electric Plant (HBRSEP)Page 23 of 30 Table 2.4-1. UHRS and GMRS for HBR2.Freq. (Hz) 10-4 UHRS (g) 10-5 UHRS (g) GMRS 100 4.20E-01 9.17E-01 4.71 E-01 90 4.23E-01 9.31 E-01 4.77E-01 80 4.27E-01 9.48E-01 4.85E-01 70 4.35E-01 9.73E-01 4.97E-01 60 4.54E-01 1.02E+00 5.19E-01 50 4.98E-01 1.11 E+00 5.66E-01 40 5.74E-01 1.25E+00 6.43E-01 35 6.21 E-01 1.35E+00 6.95E-01 30 6.63E-01 1.46E+00 7.50E-01 25 7.23E-01 1.61 E+00 8.21 E-01 20 7.92E-01 1.75E+00 8.97E-01 15 8.09E-01 1.82E+00 9.27E-01 12.5 8.35E-01 1.82E+00 9.36E-01 10 8.52E-61 1.86E+00 9.55E-01 9 8.40E-01 1.84E+00 9.42E-01 8 8.58E-01 1.84E+00 9.49E-01 7 8.98E-01 1.92E+00 9.88E-01 6 8.87E-01 1.95E+00 9.99E-01 5 8.57E-01 1.87E+00 9.61 E-01 4 8.40E-01 1.83E+00 9.39E-01 3.5 7.71 E-01 1.76E+00 8.94E-01 3 6.79E-01 1.59E+00 8.04E-01 2.5 6.08E-01 1.38E+00 7.04E-01 2 5.37E-01 1.30E+00 6.52E-01 1.5 3.97E-01 1.05E+00 5.20E-01 1.25 3.23E-01 8.58E-01 4.23E-01 1 2.26E-01 6.44E-01 3.13E-01 0.9 1.87E-01 5.52E-01 2.67E-01 0.8 1.56E-01 4.69E-01 2.26E-01 0.7 1.31 E-01 3.95E-01 1.90E-01 0.6 1.10E-01 3.25E-01 1.57E-01 0.5 8.86E-02 2.51 E-01 1.22E-01 0.4 7.09E-02 2.01 E-01 9.79E-02 0.35 6.20E-02 1.76E-01 8.57E-02 0.3 5.32E-02 1.51 E-01 7.34E-02 0.25 4.43E-02 1.26E-01 6.12E-02 0.2 3.55E-02 1.OOE-01 4.90E-02 0.15 2.66E-02 7.54E-02 *3.67E-02 0.125 2.22E-02 6.28E-02 3.06E-02 0.1 1.77E-02 5.02E-02 2.45E-02 Seismic Hazard and Screening Report H.B. Robinson Steam Electric Plant (HBRSEP)Page 24 of 30 The 1 E-4 and 1 E-5 UHRS are used to compute the GMRS at the control point and are shown in Figure 2.4-1.Mean Soil UHRS and GMRS at Robinson 2.5 2.1.5 1.5 --4A 0'i 0.5 0.1-1E-5 UHRS--GMRS-1E-4 UHRS 100 1 10 Spectral frequency, Hz Figure 2.4-1. Plots of 1 E-4 and 1 E-5 uniform hazard spectra and GMRS at control point for HBRSEP (5%-damped response spectra).3.0 Safe Shutdown Earthquake Ground Motion The design basis for HBRSEP is identified in the Updated Final Safely Analysis Report (Reference 7).3.1 Description of Spectral Shape and Anchor Point The Safe Shutdown Earthquake (SSE) was developed based on evaluation historic earthquake activity, regional and local geology, and recommendation of Dr. G. W. Housner of the California Institute of Technology. | |||
Seismic Hazard and Screening | Only one earthquake of intensity V or greater has ever been recorded within 50 miles of the site.In 1959, an earthquake of intensity V-VI (Modified Mercalli Scale) occurred about 15 miles from the site in the vicinity of McBee, SC. No permanent effects of this shock are noted in the literature or in a geologic reconnaissance, although it is presumed to have been felt at the location of the site. It is estimated that this shock had a magnitude no greater than 4.5 with an epicentral acceleration of well under 0.10 g. | ||
Seismic Hazard and Screening Report H.B. Robinson Steam Electric Plant (HBRSEP)Page 25 of 30 On the basis of historical data, it is expected that the site area could experience a shock in the order of the 1959 McBee shock once during the life of the plant. This shock could be as far distant as in 1959, or perhaps closer. On a conservative basis, Magnitude 4.5 earthquake was selected with an epicentral distance of less than ten miles. This earthquake is the design earthquake and although the probable ground acceleration would be .07 to .09g, a value of 0.1g is used. To provide an adequate margin of safety, a maximum earthquake ground acceleration of 0.2g was selected for the hypothetical SSE.The SSE is defined in terms of a PGA and a design response spectrum. | |||
Seismic Hazard and Screening | The SSE response spectra used for the Seismic Class I SSCs for the HBRSEP site have a spectral shape conforming to a Housner curve (Section 2.5 of Reference 7). The horizontal design response spectrum for the SSE was normalized to 0.2g PGA as noted in HBRSEP UFSAR Figure 2.5.2-3 (Reference 7). Table 3.1-1 shows the spectral acceleration values as a function of frequency for the 5% damped horizontal SSE.Table 3.1-i. SSE for HBRSEP (Reference 16)Frequency Spectral (Hz) Acceleration (g)100 0.2 33 0.2 13.33 0.2 10 0.23 8 0.26 5 0.3 4 0.32 3 0.3 1.641 0.24 0.33 0.07 3.2 Control Point Elevation Based on information in Table 1 from URS (Reference 16), the SSE control point elevation is defined at the top of ground surface (i.e., El. 226 feet MSL-NGVD 29, 0 ft depth).4.0 Screening Evaluation In accordance with SPID (Reference | ||
: 2) Section 3, a screening evaluation was performed as described below. | |||
(cont.) | Seismic Hazard and Screening Report H.B. Robinson Steam Electric Plant (HBRSEP) Page 26 of 30 4.1 Risk Evaluation Screening (1 to 10 Hz)In the 1 to 10 Hz part of the response spectrum, the GMRS exceeds the SSE. Therefore, the plant screens in for a risk evaluation. | ||
Seismic Hazard and Screening | |||
This process | |||
The dynamic response of the materials below the control point was represented | |||
The resulting control point | |||
Tabulated values of mean and fractile | |||
Control point mean hazard curves for oscillator frequencies of 0.5, 1, 2.5, 5, 10,25 and 100 Hz at HBRSEP.2.4 Ground Motion Response | |||
I Seismic Hazard and Screening | |||
*3.67E-02 0.125 2.22E-02 6.28E-02 3.06E- | |||
3.0 Safe Shutdown Earthquake Ground | |||
Only one earthquake of intensity V or greater has ever been recorded within 50 miles of the site.In 1959, an earthquake of intensity V-VI (Modified Mercalli Scale) occurred about 15 miles | |||
Seismic Hazard and Screening | |||
The SSE | |||
: 2) Section 3, a screening evaluation was performed | |||
Seismic Hazard and Screening | |||
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4.2 High Frequency Screening | 4.2 High Frequency Screening | ||
(> 10 Hz)For a portion of the range above 10 Hz, the GMRS exceeds the SSE. The high frequency exceedances can be addressed in the risk evaluation discussed in 4.1 above.4.3 Spent Fuel Pool Evaluation Screening (1 to 10 Hz)In the 1 to 10 Hz range of the response | (> 10 Hz)For a portion of the range above 10 Hz, the GMRS exceeds the SSE. The high frequency exceedances can be addressed in the risk evaluation discussed in 4.1 above.4.3 Spent Fuel Pool Evaluation Screening (1 to 10 Hz)In the 1 to 10 Hz range of the response spectrum, the GMRS exceeds the SSE. Therefore, the plant screens in for a spent fuel pool evaluation. | ||
5.0 Interim Actions and Assessments As described in Section 4, the GMRS developed in response to the NTTF 2.1: Seismic portion of the 10 CFR 50.54(f) Request for Information of 3/12/2012 exceeds the design basis SSE.The NRC 50.54(f) letter requests: "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." These evaluations and actions are discussed below.Consistent with NRC letter dated February 20, 2014 [Reference 10], the seismic hazard reevaluations presented herein are distinct from the current design and licensing bases of HBRSEP. Therefore, the results do not call into question the operability or functionality of SSCs and are not reportable pursuant to 10 CFR 50.72, "Immediate notification requirements for operating nuclear power reactors," and10 CFR 50.73, "Licensee event report system." 5.1 Expedited Seismic Evaluation Process An expedited seismic evaluation process (ESEP) is being performed at HBRSEP in accordance with the methodology in EPRI 3002000704 as proposed in a letter to NRC dated April 9, 2013 (Reference | |||
5.0 Interim Actions and Assessments As described in Section 4, the GMRS developed in response to the NTTF 2.1: Seismic | : 8) and agreed to by the NRC in a letter dated May 7, 2013 (Reference 9). Duke Energy plans to submit a report on the ESEP to NRC in accordance with the schedule in the April 9, 2013 letter (Reference 8)(prior to the end of December 2014).The ESEP is essentially complete. | ||
Request for Information of 3/12/2012 exceeds the design basis SSE.The NRC 50.54(f) letter requests: | An equipment list was developed, inspections were completed and evaluations were performed per EPRI Guidance as described in Reference 3.Insights from the process revealed one case where cabinet anchorage analysis warranted increased capacity for higher than design basis loading, and another case where the seismic capacity of a group of instrument racks could be increased by relatively minor work scope. | ||
"interim evaluation and actions taken or planned to | Seismic Hazard and Screening Report H.B. Robinson Steam Electric Plant (HBRSEP) Page 27 of 30 Modifications were implemented for two cabinets. | ||
These evaluations and actions are discussed below.Consistent with NRC letter dated February 20, 2014 [Reference 10], the seismic | One cabinet (MCC 'A') required modification to achieve seismic capacity greater than two times SSE ( 2 X SSE). The second cabinet was related to the first in configuration and function. | ||
and10 CFR 50.73, "Licensee event report system."5.1 Expedited Seismic Evaluation | Therefore, a similar modification was implemented for the second electrical cabinet (MCC 'B') to add seismic margin above 2 X SSE.Seismic margin above 2 X SSE was also added to a group of instrument racks (Hagen Racks)by validating the bolting integrity of the top braces (a relatively minor scope of work).5.2 Seismic Risk Estimates The NRC letter (Reference | ||
: 8) and agreed to by the NRC in a letter dated May 7, 2013 (Reference 9). | : 10) also requests that licensees provide an interim evaluation or actions to address the higher seismic hazard relative to the design basis while the expedited approach and risk evaluations are conducted. | ||
An equipment list was developed, inspections | In response to that request, NEI letter dated March 12, 2014 (Reference 11), provides seismic core damage risk estimates using the updated seismic hazards for the operating nuclear plants in the Central and Eastern United States. These risk estimates continue to support the following conclusions of the NRC GI-199 Safety/Risk Assessment: "Overall seismic core damage risk estimates are consistent with the Commission's Safety Goal Policy Statement because they are within the subsidiary objective of 1 E-4/year for core damage frequency. | ||
Seismic Hazard and Screening | The GI-1 99 Safety/Risk Assessment, based in part on information from the U.S. Nuclear Regulatory Commission's (NRC's) Individual Plant Examination of Extemal Events (IPEEE) program, indicates that no concem exists regarding adequate protection and that the current seismic design of operating reactors provides a safety margin to withstand potential earthquakes exceeding the original design basis." HBRSEP is included in the March 12, 2014 (Reference | ||
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One cabinet (MCC 'A') required modification to achieve seismic capacity greater than two times SSE ( 2 X SSE). The second cabinet | |||
Therefore, a similar modification | |||
: 10) also requests that licensees provide an interim evaluation | |||
In response to that request, NEI letter | |||
"Overall seismic core damage risk estimates are consistent with the Commission's Safety Goal Policy Statement because they are within the subsidiary objective of 1 E-4/year for core damage frequency. | |||
The GI-1 99 Safety/Risk Assessment, based in | |||
: 11) risk estimates. | : 11) risk estimates. | ||
Using | Using the methodology described in the NEI letter, the seismic core damage risk estimates for all plants were shown to be below 1 E-4/year; thus, the above conclusions apply.5.3 Individual Plant Examination of External Events The IPEEE investigations for HBRSEP followed the methodology for a full scope Seismic Margins Assessment (SMA) presented in NUREG-1407 entitled "Procedural and Submittal Guidance for the Individual Plant Examination of External Events (IPEEE) for Severe Accident Vulnerabilities,". | ||
Methodology from EPRI NP-6041 -SL were applied. | Methodology from EPRI NP-6041 -SL were applied. Walkdown screening was performed using a 0.30g NUREG/CR-0098 median soil spectrum as a Review Level Earthquake (RLE). The plant level IPEEE High Confidence of Low Probability of Failure (HCLPF) was 0.28g. The HCLPF was dependent on resolution of USI A-46 outlier conditions which have been completed. | ||
Walkdown screening | Seismic Hazard and Screening Report H.B. Robinson Steam Electric Plant (HBRSEP) Page 28 of 30 5.4 Walkdowns to Address NRC Fukushima NTTF Recommendation 2.3 Walkdowns have been completed for HBRSEP in accordance with the EPRI seismic walkdown guidance (Reference 17); including inaccessible items. Potentially adverse seismic conditions (PASC) found were entered into the corrective action program (CAP) and resolved. | ||
Seismic Hazard and Screening | None of the PASC items challenged the operability of the plant. There were no vulnerabilities identified under IPEEE, however, identified enhancements were reviewed and found to be complete.Duke confirmed through the walkdowns that the existing monitoring and maintenance procedures keep the plant consistent with the design basis.6.0 Conclusions In accordance with the 50.54(f) request for information, a seismic hazard and screening evaluation was performed for HBRSEP. A GMRS was developed solely for the purpose of screening for additional evaluations in accordance with the SPID (Reference 2).Based on the results of the screening evaluation, HBRSEP screens in for risk evaluation, a spent fuel pool evaluation and a High Frequency Confirmation. | ||
Page 28 of | Seismic Hazard and Screening Report H.B. Robinson Steam Electric Plant (HBRSEP) Page 29 of 30 7.0 References | ||
None of | : 1. United States Nuclear Regulatory Commission (USNRC), E. Leeds and M. Johnson, Letter to All Power Reactor Licensees et al., "Request for Information Pursuant to Title 10 of the Code of Federal Regulations 50.54(f) Regarding Recommendations 2.1, 2.3, and 9.3, of the Near-Term Task Force Review of Insights from the Fukushima Dai-ichi Accident", March 12, 2012.2. Electric Power Research Institute (EPRI), Final Report 1025287, "Seismic Evaluation Guidance: | ||
Duke confirmed through the walkdowns that the existing monitoring and maintenance procedures keep the plant consistent with the design basis.6.0 Conclusions In accordance with the 50.54(f) request for information, a seismic hazard and screening evaluation was performed for HBRSEP. A GMRS was developed solely for the purpose | Screening, Prioritization and Implementation Details (SPID) for the Resolution of Fukushima Near-Term Task Force Recommendation 2.1: Seismic", February 2013.3. Electric Power Research Institute (EPRI), Final Report No. 3002000704, "Seismic Evaluation Guidance: | ||
Seismic Hazard and Screening | Augmented Approach for the Resolution of Fukushima Near-Term Task Force Recommendation 2.1: Seismic", May 2013.4. United States Nuclear Regulatory Commission (USNRC), NUREG-2115, Department of Energy/Office of Nuclear Energy (DOE/NE)-0140, EPRI 1021097, "Central and Eastern United States Seismic Source Characterization for Nuclear Facilities", 6 Volumes, 2012.5. Electric Power Research Institute (EPRI), Final Report No. 3002000717, "EPRI (2004, 2006) Ground-Motion Model (GMM) Review Project", June 2013.6. United States Nuclear Regulatory Commission (USNRC), Regulatory Guide (RG) 1.208,"A Performance-Based Approach to Define the Site-Specific Earthquake Ground Motion", March 2007.7. Progress Energy, "H.B. Robinson Nuclear Power Plant Unit 2 Updated Final Safety Analysis Report", Revision 24.8. Nuclear Energy Institute (NEI), A. Pietrangelo, Letter to D. Skeen of the USNRC,"Proposed Path Forward for NTTF Recommendation 2.1: Seismic Reevaluations", April 9, 2013 (ML13101 A379).9. United States Nuclear Regulatory Commission (USNRC), E. Leeds, Letter to J. Pollock of NEI, "Electric Power Research Institute Final Draft Report XXXXXX, 'Seismic Evaluation Guidance: | ||
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: 1. United States Nuclear Regulatory Commission (USNRC), | |||
E. Leeds and M. Johnson,Letter to All Power Reactor Licensees et al., "Request for Information Pursuant to | |||
Regarding Recommendations 2.1, 2.3,and 9.3, of the Near-Term Task Force Review of Insights from the Fukushima Dai- | |||
March 12, 2012.2. Electric Power Research Institute (EPRI), Final Report 1025287, "Seismic Evaluation Guidance: | |||
Screening, Prioritization and Implementation Details (SPID) for the Resolution of Fukushima Near-Term Task Force Recommendation 2.1: Seismic", | |||
February 2013.3. Electric Power Research Institute (EPRI), Final Report No. 3002000704, " | |||
Augmented Approach for the Resolution of Fukushima Near-Term Task Force Recommendation 2.1: Seismic", | |||
May 2013.4. United States Nuclear Regulatory Commission (USNRC), | |||
NUREG-2115, Department | |||
6 Volumes, 2012.5. Electric Power Research Institute (EPRI), Final Report No. 3002000717, "EPRI (2004,2006) Ground-Motion Model (GMM) Review Project", | |||
June 2013.6. United States Nuclear Regulatory Commission (USNRC), | |||
Regulatory Guide (RG) 1.208,"A Performance-Based Approach to Define the Site-Specific Earthquake | |||
March 2007.7. Progress Energy, "H.B. Robinson Nuclear Power Plant Unit 2 Updated Final | |||
Revision 24.8. Nuclear Energy Institute (NEI), A. Pietrangelo, Letter to D. Skeen of the USNRC,"Proposed Path Forward for NTTF Recommendation 2.1: Seismic Reevaluations", | |||
E. Leeds, Letter to J. | |||
Augmented Approach for the Resolution of Fukushima Near-Term Task Force Recommendation 2.1: Seismic,' | Augmented Approach for the Resolution of Fukushima Near-Term Task Force Recommendation 2.1: Seismic,' | ||
as an Acceptable |
Revision as of 18:20, 9 July 2018
ML14099A204 | |
Person / Time | |
---|---|
Site: | Robinson |
Issue date: | 03/31/2014 |
From: | Gideon W R Duke Energy Progress |
To: | Document Control Desk, Office of Nuclear Reactor Regulation |
References | |
RNP-RA/14-0013 | |
Download: ML14099A204 (42) | |
Text
W. R. Gfdeon H. B. Robinson Steam Electric Plant Unit 2 DUKE Site Vice President ENERGYDuke Engy Pogres ENERG3581 West Entrance Romo Hartsville, SC 29550 0: 843 857 1701 F" 843 857 1319 Rmndy.Gideon*duke-energy.com 10 CFR 50.54(f)Serial: RNP-RN14-0013 MAR 3 12014 U.S. Nuclear Regulatory Commission Attn: Document Control Desk 11555 Rockville Pike Rockville, MD 20852 H. B. ROBINSON STEAM ELECTRIC PLANT, UNIT NO. 2 DOCKET NO. 50-261 / RENEWED LICENSE NO. DPR-23
Subject:
Seismic Hazard Evaluation, Response to NRC 10 CFR 50.54(f) Request for Information Pursuant to Title 10 of the Code of Federal Regulations 50.54(f)Regarding Recommendations 2.1, 2.3 and 9.3 of the Near-Term Task Force Review of Insights from the Fukushima Dai-ichi Accident
References:
- 1. NRC letter, Request for Information Pursuant to Title 10 of the Code of Federal Regulations 50.54(o Regarding Recommendations 2.1, 2.3, and 9.3, of the Near-Term Task Force Review of Insights from the Fukushima Dai-ichi Accident, dated March 12, 2012 (ADAMS Accession Number ML12056A046)
- 2. NRC letter, Endorsement of EPRI Final Draft Report 1025287, "Seismic Evaluation Guidance," dated February 15, 2013 (ADAMS Accession Number ML1 2319A074)3. 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, dated February 2013 (ADAMS Accession Number ML1 2333A1 70)4. NEI letter, Proposed Path Forward for NTTF Recommendation 2.1: Seismic Reevaluations, dated April 9, 2013 (ADAMS Accession Number ML13101A319)
- 5. NRC letter, Electric Power Research Institute Final Draft Report XXXXXX, "Seismic Evaluation Guidance:
Augmented Approach for the Resolution of Fukushima Near-Term Task Force Recommendation
- 2. 1: Seismic, "as an Acceptable Alternative to the March 12, 201Z Information Request for Seismic Reevaluations, dated May 7, 2013 (ADAMS Accession Number ML13106A331)
- 6. NEI Letter, Seismic Evaluations for Plants in the Central and Eastern United States, dated March 12,2014 (ADAMS Accession Nos. ML14083A584, ML14083A586 and ML14083A587) 4A0o U. S. Nuclear Regulatory Commission Serial: RNP-RA/14-0013 Page 3 of 3 Ladies and Gentlemen:
On March 12, 2012, the Nuclear Regulatory Commission (NRC) issued Reference 1 to all power reactor licensees and holders of construction permits in active or deferred status. Enclosure 1 of Reference 1 requested each addressee in the Central and Eastern United States (CEUS) to submit a written response consistent with the requested seismic hazard evaluation information (items 1 through 7) by September 12, 2013. By letter dated February 15, 2013, the NRC issued Reference 2, endorsing the Reference 3 industry guidance for responding to the seismic evaluation in Reference
- 1. Section 4 of Reference 3 identifies the detailed information to be included in the seismic hazard evaluation submittals.
On April 9, 2013, the Nuclear Energy Institute (NEI) submitted Reference 4 to the NRC, requesting NRC agreement to delay submittal of part of the CEUS seismic hazard evaluation information so that an update to the Electric Power Research Institute (EPRI) (2004, 2006)ground motion attenuation model could be completed and used to develop that information.
NEI proposed that descriptions of subsurface materials and properties and base case velocity profiles (items 3a and 3b in Section 4 of Reference
- 3) be submitted to the NRC by September 12, 2013, with the remaining seismic hazard and screening information submitted to the NRC by March 31, 2014. In Reference 5, the NRC agreed with this recommendation.
Reference 3 contains industry guidance and detailed information to be included in the Seismic Hazard Evaluation submittals.
The attached Seismic Hazard Evaluation for H. B. Robinson Steam Electric Plant, Unit No. 2 provides the information described in Section 4 of Reference 3 in accordance with the schedule identified in Reference
- 4. As discussed in the Enclosure to this letter, seismic hazard curves and a Ground Motion Response Spectrum (GMRS) were developed using current methodology.
This GMRS is compared to the design basis Safe Shutdown Earthquake (SSE) response spectrum and the Individual Plant Examination of External Events (IPEEE) High Confidence of Low Probability of Failure (HCLPF) spectrum in the Enclosure.
As discussed within Reference 1, NRC acknowledged that the current regulatory approach and the resultant plant capabilities provides reasonable confidence that an accident with consequences similar to the Fukushima event is unlikely with nuclear power plants located in the United States. The NRC concluded that continued plant operation does not pose an imminent risk to the public health and safety.By letter dated March 12, 2014 (Reference 9), NEI provided the NRC with seismic core damage risk estimates based on updated seismic hazard information as it applies to operating nuclear reactors in the CEUS, which includes H. B. Robinson Steam Electric Plant, Unit No. 2. These risk assessments continue to support the conclusions of the NRC Generic Issue-1 99"Safety/Risk Assessment" and indicate that current seismic design of operating reactors provide adequate protection and safety margin to withstand potential earthquakes that exceed the original design basis.In accordance with Enclosure 1 of Reference 1, H. B. Robinson Steam Electric Plant, Unit No. 2 screens in for performing a seismic probabilistic risk assessment (SPRA).This letter contains no new regulatory commitments.
U. S. Nuclear Regulatory Commission Serial: RNP-RA/14-0013 Page 3 of 3 If you have any questions or require additional information, please contact Richard Hightower, Manager, Nuclear Regulatory Affairs at (843)-857-1329.
I declare under the penalty of perjury that the foregoing is true and correct.Executed on MAR 3 12014 Sincerely, W. R. Gideon Site Vice President WRG/shc
Enclosure:
Seismic Hazard Evaluation cc: Mr. K. M. Ellis, NRC Senior Resident Inspector Mr. S. P. Lingam, NRC Project Manager, NRR Mr. V. M. McCree, NRC Region II Administrator U. S. Nuclear Regulatory Commission Enclosure to Serial: RNP-RA/14-0013 39 Pages including this cover ENCLOSURE SEISMIC HAZARD EVALUATION FOR H. B. ROBINSON STEAM ELECTRIC PLANT, UNIT NO. 2 DOCKET NO. 50-261 / RENEWED LICENSE NO. DPR-23 TABLE OF CONTENTS Section Page 1.0 Introduction
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1 2.0 Seismic Hazard Reevaluation
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2 2.1 Regional and Local Geology ...............................................................
3 2.2 Probabilistic Seismic Hazard Analysis ..................................................
4 2.2.1 Probabilistic Seismic Hazard Analysis Results ....................................
4 2.2.2 Base Rock Seismic Hazard Curves ................................................
9 2.3 Site Response Evaluation
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9 2.3.1 Description of Subsurface Material ...................................................
9 2.3.2 Development of Base Case Profiles and Nonlinear Material Properties
...... 11 2.3.3 Randomization of Base Case Profiles ..............................................
14 2.3.4 Input Spectra ..............................................................................
15 2.3.5 Methodology
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15 2.3.6 Amplification Functions
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15 2.3.7 Control Point Seismic Hazard Curves ..............................................
22 2.4 Ground Motion Response Spectrum ....................................................
22 3.0 Safe Shutdown Earthquake Ground Motion ............................................
24 3.1 Description of Spectral Shape and Anchor Point .....................................
24 3.2 Control Point Elevation
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25 4.0 Screening Evaluation
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25 4.1 Risk Evaluation Screening (1 to 10 Hz) ..................................................
26 4.2 High Frequency Screening
(> 10 Hz) ....................................................
26 4.3 Spent Fuel Pool Evaluation Screening (1 to 10 Hz) .....................
.26 5.0 Interim Actions and Assessments
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26 5.1 Expedited Seismic Evaluation Program ................................................
26 5.2 Seismic Risk Estimates
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27 5.3 Individual Plant Examination of External Events ......................................
27 5.4 Walkdowns to Address NRC Fukushima NTTF Recommendation 2.3 ............
27 6.0 Conclusions
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28 7.0 References
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29 Appendix A ..................................................................................................
A-1 i Seismic Hazard and Screening Report H.B. Robinson Steam Electric Plant (HBRSEP) Page 1 of 30 1.0 Introduction Following the accident at the Fukushima Dai-ichi nuclear power plant resulting from the March 11, 2011, Great Tohoku Earthquake and subsequent tsunami, the NRC Commission established a Near Term Task Force (NTTF) to conduct a systematic review of NRC processes and regulations and to determine if the agency should make additional improvements to its regulatory system. The NTTF developed a set of recommendations intended to clarify and strengthen the regulatory framework for protection against natural phenomena.
Subsequently, the NRC issued a 50.54(f) letter on March 12, 2012 (Reference 1), requesting information to assure that these recommendations are addressed by all U.S. nuclear power plants. The *50.54(f) letter requests that licensees and holders of construction permits under 10 CFR Part 50 reevaluate the seismic hazards at their sites against present-day NRC requirements.
Depending on the comparison between the reevaluated seismic .hazard and the current design basis, the result is either no further risk evaluation or the performance of a seismic risk assessment.
Risk assessment approaches acceptable to the staff include a seismic probabilistic risk assessment (SPRA), or a seismic margin assessment (SMA). Based upon the risk assessment results, the NRC staff will determine whether additional regulatory actions are necessary.
This report provides the information requested in items (1) through (7) of the "Requested Information" section and Attachment 1 of the 50.54(f) letter pertaining to NTTF Recommendation 2.1 for the H.B. Robinson Steam Electric Plant (HBRSEP) site, located in Darlington County, South Carolina (SC). In providing this information, HBRSEP followed the guidance provided in the Seismic Evaluation Guidance:
Screening, Prioritization, and Implementation Details (SPID) for the Resolution of Fukushima Near-Term Task Force Recommendation 2.1: Seismic (EPRI 1025287, 2013) (Reference 2). The Augmented Approach, Seismic Evaluation Guidance:
Augmented Approach for the Resolution of Fukushima Near-Term Task Force Recommendation 2.1: Seismic (EPRI 3002000704, 2013) (Reference 3), has been developed as the process for evaluating critical plant equipment as an interim action to demonstrate additional plant safety margin, prior to performing the complete plant seismic risk evaluations.
The original geologic and seismic siting investigations for HBRSEP were performed using a detailed geologic study of the region and the site to establish the geologic suitability of the site for the nuclear unit. Additional data utilized in the geologic and seismic siting investigations were obtained from the U. S. Atomic Energy Commission (USAEC) Savannah River Operations Office (Appendix 2.5A of Reference 7), Dr.'s J. L. Stuckey and L. L. Smith (Appendix 2.5C of Reference 7), and Perry Byerly (Appendix 2.5D of Reference 7).The Safe Shutdown Earthquake (SSE) was developed based on evaluation of historic earthquake activity, regional and local geology, and recommendation of Dr. G. W. Housner of the California Institute of Technology.
The SSE was used for the design of seismic Class I systems, structures, and components.
Seismic Hazard and Screening Report H.B. Robinson Steam Electric Plant (HBRSEP) Page 2 of 30 The General Design Criteria (GDC) in existence at the time HBRSEP was licensed (July, 1970)for operation were contained in Proposed Appendix A to 10CFR50, General Design Criteria for Nuclear Power Plants, published in the Federal Register on July 11, 1967. (Appendix A to 1 OCFR50, effective in 1971 and subsequently amended, is somewhat different from the proposed 1967 criteria.)
HBRSEP was evaluated with respect to the proposed 1967 GDC and the original Final Safety Analysis Report (FSAR) (Reference
- 7) contained a discussion of the criteria as well as a summary of the criteria by groups. FSAR, Sections 3.1.1.2 and 3.1.2 present that discussion without substantive change in order to preserve the original basis for licensing.
In response to the 50.54(f) letter and following the guidance provided in the SPID (Reference 2), a seismic hazard reevaluation was performed.
For screening purposes, a Ground Motion Response Spectrum (GMRS) was developed.
Based on the results of the screening evaluation, HBRSEP screens in for risk evaluation, a Spent Fuel Pool evaluation, and a High Frequency Confirmation.
2.0 Seismic Hazard Reevaluation HBRSEP is located in northwest Darlington County, SC, approximately 3 miles west-northwest of Hartsville, SC; 25 miles northwest of Florence, SC; 35 miles north-northeast of Sumter, SC;and 56 miles east-northeast of Columbia, SC. The plant is on the southwest shore of Lake Robinson, a cooling impoundment of Black Creek. The site is located in the Coastal Plain physiographic province about 15 miles southeast of the Piedmont province.
The Coastal Plain is composed of largely unconsolidated sediments above a slightly sloping surface of crystalline rock. The basement crystallines in the Piedmont and below the Coastal Plain are composed largely of granite, gneiss, phyllite, and schist and dip to the southeast from 10 ft to 40 ft per mile.The normal regional dip of the Coastal Plain sediments is toward the southeast at about 8 ft to 30 ft per mile, the greater dips being in the deeper strata.Only one earthquake with intensity of V or greater has ever been recorded within 50 miles of the site. In 1959, an earthquake with intensity of V-VI (Modified Mercalli Scale) occurred about 15 miles from the site in the vicinity of McBee, SC. No permanent effects of this shock are noted in the literature or in a geologic reconnaissance, although it is presumed to have been felt at the location of the site. It is estimated that this shock had a magnitude no greater than 4.5 with an epicentral acceleration of well under 0.10 g.On the basis of the historical data, it is expected that the site area could experience a shock on the order of the 1959 McBee shock once during the life of the plant. A Magnitude 4.5 earthquake with an epicentral distance of less than ten miles was selected as the design earthquake.
Although the probable ground acceleration for this earthquake would be 0.07 g to 0.09 g, a conservative value of 0.1 g is used for the Operational Basis Earthquake (OBE). An SSE with a maximum ground acceleration of 0.2 g was selected to provide an adequate margin of safety.
Seismic Hazard and Screening Report H.B. Robinson Steam Electric Plant (HBRSEP) Page 3 of 30 2.1 Regional and Local Geology Regional Geoloqgy In South Carolina, the Coastal Plain is composed of largely unconsolidated sediments which overlie a slightly sloping surface of crystalline rock. These crystallines are of Precambrian and early Paleozoic age with subordinate sandstones and intrusive diorities of Triassic age. Triassic sediments have been faulted into the ancient crystallines.
Faulted Triassic basins are evident in the Piedmont province and deep wells have located Triassic rocks in widely divergent areas beneath the Coastal Plain. Overlying the Precambrian, Paleozoic, and Triassic rocks, are the sediments of the Coastal Plain. These sediments are composed of sands, gravels, clays, shales, and limestones which range in age from Cretaceous to Pleistocene.
The Coastal Plain itself is divided into the upper Coastal Plain and the lower Coastal Plain by what has been termed the Orangeburg Scarp, an erosional feature representing a shoreline formed during Miocene times. The elevation of the Upper Coastal Plain ranges from approximately 210 ft above Mean Sea Level, (MSL) at the Orangeburg Scarp, and 450 ft to 500 ft above MSL, at the Fall Zone. The Upper Coastal Plain is the outcrop zone of the Tuscaloosa (Middendorf)
Formation of late Cretaceous age, but most of the area is blanketed by more recent alluvial deposits of sand and gravel. The elevation of the Lower Coastal Plain ranges from approximately 210 ft above MSL, at the Orangeburg Scarp to sea level at the coast. The major structural features of the region include Triassic grabens (downfaulted basins) and the Cape Fear Arch, a basement ridge which trends southeastward from the Fall Line to the Atlantic Coast just northeast of the North Carolina-South Carolina boundary.
The Cape Fear Arch has caused the overlying Coastal Plain sediments to dip away from its structure, thereby modifying the normal regional dips on its flanks.Local Geoloqy The surficial materials at the HBRSEP site are recent sands or soils developed from the Middendorf.
Because of the high quartz content of the sands and the climatic environment, the surficial soils may not weather sufficiently to differ considerably from the parent material.
From an engineering standpoint, the difference is minor.The subsurface materials encountered in the test holes drilled at the site are completely consistent with recent alluvium and Middendorf Formations encountered throughout the vicinity.Discontinuities within the strata are sedimentary and no structural deformation is apparent in the Middendorf Formation in the site area.Triassic basins are known in the area; however, it is believed that the likelihood of a Triassic basin at the site is quite small. The basement rock at the site is considered to be Piedmont crystalline since the results of the seismic surveys indicate a high velocity material at a depth consistent with the depth of Piedmont crystallinesencountered in wells in the area.
Seismic Hazard and Screening Report H.B. Robinson Steam Electric Plant (HBRSEP) Page 4 of 30 The upper alluvial sands and gravels are moderately compact. Layers of compressible material occur in the upper 30 ft to 50 ft. Because of the quantity of fines in the sand and gravel, it cannot be considered free-draining material.
The underlying Middendorf contains compact, relatively incompressible sands and firm to hard clayey soils. Several strata of cemented sandstone were encountered in the borings at depths of approximately 90 ft to 100 ft.2.2 Probabilistic Seismic Hazard Analysis 2.2. 1 Probabilistic Seismic Hazard Analysis Results In accordance with the 50.54(f) letter and following the guidance in the SPID (Reference 2), a probabilistic seismic hazard analysis (PSHA) was completed using the recently developed Central and Eastern United States Seismic Source Characterization (CEUS-SSC) for Nuclear Facilities (Reference
- 4) together with the updated EPRI Ground-Motion Model (GMM) for the CEUS (Reference 5). A site-specific review of the CEUS-SSC earthquake catalog was also performed as described below, and these results are incorporated into the PSHA for the HBRSEP site. For the PSHA, a lower-bound moment magnitude of 5.0 was used, as specified in the 50.54(f) letter.Site-Specific CEUS-SSC Catalog Review A site-specific review (Reference, 13) of the CEUS-SSC catalog published in the CEUS-SSC was performed with regard to two issues: (1) identification of additional reservoir induced seismicity (RIS) earthquakes in the southeastern US and (2): locations of earthquakes in South Carolina near the time of the 1886 Charleston, SC earthquake sequence.In developing the CEUS-SSC catalog, earthquakes identified as RIS were removed from the final earthquake listing. The source for this identification in the southeastern US was the set of available Southeast US Seismic Network (SEUSSN) Bulletins.
The master list contained 120 earthquakes.
Sixteen of these were large enough to be in the CEUS-SSC catalog. These earthquakes occurred primarily near Monticello Reservoir and Lake Keowee. These earthquakes were removed from the final (Version 7) CEUS-SSC catalog published in NUREG-2115.Additional reviews were performed of available published information to identify potential additional RIS earthquakes that are in the CEUS-SSC catalog. The basis for each of the potential RIS records was reviewed, taking into consideration the magnitude of the earthquake and depth, proximity to a reservoir, timing of the earthquake versus the filling of the reservoir, and proximity to a nuclear plant.Thirty additional RI or potentially RI earthquakes were identified in the CEUS-SSC catalog. Of these, thirteen were large enough (E[M] > 2.9) to potentially affect recurrence calculations.
Some of these were identified as dependent events of other earthquakes in the catalog. After Seismic Hazard and Screening Report H.B. Robinson Steam Electric Plant (HBRSEP) Page 5 of 30 review, it was determined that all thirty RI or potentially RI earthquakes should be removed from the catalog. Table 2.2.1-1 lists the specific earthquake database records reviewed.Seven additional earthquakes in the CEUS-SSC catalog from the time period 1799 to 1888 in South Carolina were also identified as being potentially mislocated (Table 2.2.1-2).
The majority of these earthquakes have locations and times that come from the USGS's earthquake catalog used for seismic hazard mapping. The primary source of the USGS catalog is the NCEER-91 catalog. The events in question have alternative locations in the SUSN catalog that place them at the location of the 1886 Charleston, SC main shock. A review was performed of the identification of these earthquakes and assignment of these locations in the development of the CEUS-SSC catalog in light of additional information in the paper by W.H. Bakun and M.G.Hopper (2004, "Magnitudes and Locations of the 1811-1812 New Madrid, Missouri, and the 1886 Charleston, South Carolina, Earthquakes," Bulletin of the Seismological Society of America, 94, 64-75) and recent information provided by Donald Stevenson and Dr. Pradeep Talwani.The review identified another potential duplicate record. Bakun and Hopper (2004) also studied the Charleston aftershock on 1886/11/5 17:20 and found a location near Charleston, but slightly inland from other locations.
Talwani and Sharma (1999) also concluded that this earthquake occurred at a slightly different location than other Charleston aftershocks.
This earthquake appears in the CEUS-SSC catalog as TMP02071.
There is also an event TMP02072 that is listed in the USGS catalog with time 12:25 with a location to the northwest of Charleston.
Both events were identified as Charleston aftershocks in the declustering, but the timing suggests that they may be duplicates.
The recommendation was to remove TMP02072 and use the magnitude and location given in Bakun and Hopper for TMP02071.An additional review was performed of earthquake locations provided by Seeber and Armbruster (1987). These locations and size assessments were incorporated into the NCEER-91 catalog and then into the USGS catalog used as the primary source for the CEUS-SSC catalog. The original Seeber and Armbruster (1987) listing was also incorporated into the CEUS-SSC catalog, along with their listed values of felt area. During the review, the classification of nine additional earthquakes at locations distance from Charleston significant to hazard (EtM]>2.9) were changed from dependent to independent.
Previously, these earthquakes had been classified as dependent earthquakes in clusters associated with the earthquakes identified above. The information for each of these earthquakes was reviewed, including additional information provided by Stevenson and Talwani.Table 2.2.1-3 summarizes the assessment of the larger events in the CEUS-SSC catalog located at sufficient distance from Charleston to not be identified as aftershocks of the 1886/09/01 main shock.
Seismic Hazard and Screening Report H.B. Robinson Steam Electric Plant (HBRSEP)Page 6 of 30 Table 2.2.1-1 Summary of RIS Earthquake Review Comment I TMPID yr mo Dy hr mn sec lat Ion depth E[M] Disposition TMP07012 1969 12 13 10 19 29.7 35.04 -82.85 6 3.46 Retain as non RIS TMP07159 1971 7 13 11 42 26 34.8 -83 n/a 3.63 Possible RIS........................................
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Retain as non TMP07565 1974 8 2 8 52 11.1 33.91 -82.53 4 3.91 Ris RIS TMP08078 1975 11 25 15 17 34.8 34.93 -82.9 10* 3.21 RIS TMP08787 1977 9 7 14 41 32.7 34.982 -82.927 n/a 2.77 RIS TMP08971 1978 1 25 8 29 39 34.301 -81.234 5** 2.6 RIS TMP09354 1978 8 27 10 23 8 34.313 -81.337 2 2.93 RIS TMP08998 1978 2 10 20 23 38.7 34.343 -81.348 1 2.77 Possible RIS TMP08999 1978 2 11 0 19 0,7 34,343 -81.35 3 2 77 Possible RIS TMP09000 1978 2 11 5 19 0.2 34.346 -81.349 1 2.93 Possible RIS TMP09006 1978 2 14 12 45 72 34.342 -81.346 2 2.77 Possible RIS..................................
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TMP09006 1978 2 14 12 14 3.2 34.349 -81.346 2 2.77 Possible RIS............
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TMP09014 1978 2 16 2 14 33.4 34.332 -81.362 2 2.85 Possible RIS TMP09023 1978 2 22 7 13 25.1 34.327 -81.35 1 2.85 Possible RIS TMP09024 1978 2 22 12 13 24.3 34.339 -81.35 1 -3.00 Possible RIS TMP09002 1978 2 22 13 4 59.2 34.356 -81.352 0 2 .77 Possible RIS 1MP09027 1978 2 24 7 34 10.5 34.334 -81.348 1 2.93 Possible RIS TMP09029 1978 2 25 4 2 42.7 34.345 -81.351 1 2.77 Possible RIS TMP09031 1978 2 26 6 52 35.4 34.315 -81.297 1 2.85 Possible RIS TMP09032 1978 2 26 11 52 33 34.391 -81.361 1 3.00 Possible RIS........ ................................
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TMP09033 1978 2 26 18 17 48.8 34.321 -81.348 0 3.08 Possible RIS........ ....... .......................
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TMP09343 1978 8 24 10 23 7.6 34.311 -81.341 2 2.85 Possible RIS TMP09355 1978 8 27 10 23 8 34.313 -81.337 7 2.77 Possible RIS TMP09460 1978 10 27 16 27 18.1 34.302 -81.326 2 3.08 RIS TMP09518 1978 11 24 11 54 40.9 34.296 -81.347 1 2.85 Possible RIS TMP10034 1979 8 26 1 31 45 34.916 -82.956 1 3.64 RIS TMP39374 1979 10 8 8 54 19.4 34.31 -81.33 2 2.85 RIS.... .............................
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TMP10104 1979 10 8 23 20 11 34.306 -81.344 1 3.16 RIS.........
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TMP10506 1980 7 29 1 10 22.7 34.351 -81.364 1 3.31 Possible RIS TMP16282 1988 1 27 22 5 42.9 34.189 -82.75 6.1 2.32 RIS* depth 17 km in RANDJ** depth 1 km in Stover & Coffman Seismic Hazard and Screening Report H.B. Robinson Steam Electric Plant (HBRSEP)Page 7 of 30 Table 2.2.1-2 Potential Charleston SC Area Aftershocks from CEUS-SSC Catalog Source of Catalog TMPID yr Mo Dy hr mn sec Lat Ion E[M] Location USGSnd_000145 TMP00331 1799 4 11 8 20 0 33.95 -80.18 4.68 Revised by Jeff Munsey of TVA based on Bakun and Hopper Method
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TMP01089 1860 1 19 23 0 0 33.68 -80.57 4.21 USGSnd_000427
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TMP01731 1886 9 1 6 0 0 33.91 -82.02 4.54 SeebArm87...000014 TMP01739 1886 9 1 9 45 0 34.3 -82.86 4.17 USGSnd_000771
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TMP02019 1886 10 22 5 0 0 34.71 -81.66 4.13 USGSnd_000805
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TMP02025 1886 10 22 14 45 0 3.7 -81.01 4.5 UGnd_000807
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-TMP02360 1888 1 12 9 55 0 34.18 -80.17 4.33 USGSnd_000860 Table 2.2.1-3 Summary of Events Affected by the Charleston Aftershock Review TMPID yr Mo Dy Hr Mn sec lat Ion Comment / Disposition TMP00331 1799 4 11 8 20 0 33.95 -80.18 Retainasis
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.................... e i ~ :a i d ' a n i i a -........ ...TMP01089 1860 1 19 23 0 0 33.68 -80.57 Mo o 10 E[M] on 10..............
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Event removed from catalog as a duplicate of TMP01 732.TMP01731 1886 9 1 6 0 0 33.91 -82.02 Location and magnitude of TMP01732.do not require modification Event removed from catalog as a duplicate of TMP01738.TMP01739 1886 9 1 14* 45 0 34.04 -82.9 Location and magnitude of TMP01738 do not require modification
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.... ......TMP01942 1886 9 28 3 0 0 34.7 -81.62 Consider as a false event..................................
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.....TMP02002 1886 10 12 11 0 I0 34.14 -81.33 Not use reported felt area, event 1 0 0becomes < E[M] 2.9 TMP02019 1886 10 22. 5 0 0 34.71 -81.66 Event removed from catalog as a duplicate of TMP02023 Magnitude taken from Bakun TMP02023 1886 10 22 10 20 32.9 -80 and Hopper (2004)............................
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...d .H.° P r..2.. ° °... t)..... .........................................
TMP02024 1886 10 22 10* 25 I , 33.69 -81 Event removed from catalog as TMP0024 188 ' 10 2 1* 2 .3.69 -81 a duplicate of TM P02023.. ...... .. ...............
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....... ......d.....of T M 0 2 2 0 33.87 Location moved to Charleston, TMP02025 1886 10 22 14 45 0 33.87 -81.01 magnitude taken from Bakun... .. .. ..... ...... .. .. .. .... ...... ..... .. ... .. ..... .. .. ... .. ....... .. .........
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Seismic Hazard and Screening Report H.B. Robinson Steam Electric Plant (HBRSEP)Page 8 of 30 TMPID yr Mo Dy Hr Mn sec lat Ion Comment / Disposition and Hopper (2004)TMP02068 1886 11 5 5 0 0 33.38 -82.49 Not use reported felt area, event becomes < E[M] 2.9 TMP02071 1886 11 5 17 20 0 32.9 -80 Magnitude taken from Bakun and Hopper (2004)TMP02072 1886 11 5 12 25 33.4 -80.42 Event removed from catalog as a duplicate of TMP02071.TMP02134 1886 12 8 10 25 0 34.039 -80.886 Revise 10 from 4.5 to 4 TMP02136 1886 12 11 21 0 0 34.18 -82.06 Retain as is TMP02173 1887 1 12 11 0 0 34.35 -82.42 Retain as less than E[M] 2.9, remove felt area TMP02210 1887 3 4 10 0 0 33.74 -81.5 Not use reported felt area, event becomes < E[M] 2.9 TMP02360 1888 1 12 9 55 0 34.18 -80.17 Event removed from catalog as a duplicate of TMP39326.TMP02393 1888 4 5 0 0 0 34.21 -81.534 Retain, reduce to 10 4, E[M] less than 2.9 TMP02423 1888 8 15 23 30 0 34,37 -81.08 Retain as is* Change in hour.Probabilistic Seismic Hazard Analysis For the PSHA, the CEUS-SSC (Reference
- 4) background seismic sources out to a distance of 400 miles (640 kin) around the site were included.
This distance exceeds the 200 mile (320 km)recommendation contained in Reg. Guide 1.208 (Reference
- 6) and was chosen for completeness.
Background sources included in this site analysis are the following:
- 1. Atlantic Highly Extended Crust (AHEX)2. Extended Continental Crust-Atlantic Margin (ECC.AM)3. Extended Continental Crust-Gulf Coast (ECC_GC)4. Mesozoic and younger extended prior -narrow (MESE-N)5. Mesozoic and younger extended prior -wide (MESE-W)6. Midcontinent-Craton alternative A (MIDCA)7. Midcontinent-Craton alternative B (MIDCB)8. Midcontinent-Craton alternative C (MIDCC)9. Midcontinent-Craton alternative D (MIDCD)10. Non-Mesozoic and younger extended prior -narrow (NMESE-N)11. Non-Mesozoic and younger extended prior -wide (NMESE-W)12. Paleozoic Extended Crust narrow (PEZN)13. Paleozoic Extended Crust wide (PEZW)14. Reelfoot Rift including the Rough Creek Graben (RR-RCG)15. Study region (STUDYR)
Seismic Hazard and Screening Report H.B. Robinson Steam Electric Plant (HBRSEP) Page 9 of 30 For sources of large magnitude earthquakes, designated Repeated Large Magnitude Earthquake (RLME) sources in CEUS-SSC (Reference 4), the following sources lie within 1,000 km of the site and were included in the analysis: 1. Charleston
- 2. Commerce 3. Eastern Rift Margin Fault northern segment (ERM-N)4. Eastern Rift Margin Fault southern segment (ERM-S)5. Marianna 6. New Madrid Fault System (NMFS)7. Wabash Valley For each of the above background and RLME sources, the mid-continent version of the updated CEUS EPRI GMM was used.2.2.2 Base Rock Seismic Hazard Curves Consistent with the SPID (Reference 2), base rock seismic hazard curves are not provided as the site amplification approach referred to as Method 3 has been used. Seismic hazard curves are shown below in Section 3 at the SSE control point elevation.
2.3 Site Response Evaluation Following the guidance contained in Seismic Enclosure 1 of the 3/12/2012 50.54(f) Request for Information and in the SPID (CEUS-SSC, 2013a) for nuclear power plant sites that are not sited on hard rock (defined as 2.83 km/sec), a site response analysis was performed for HBRSEP.2.3.1 Description of Subsurface Material The HBRSEP is located in the Coastal Plain Physiographic Province of South Carolina.
The general site conditions consist of about 50 ft (15.2 m) of recent alluvium overlying about 400 ft (122 m) of stiff sands, sandstones, and mudstones.
Precambrian basement consisting of Piedmont crystalline rocks lie below the sedimentary section (Reference 16).Table 2.3.1-1 shows the recommended geotechnical properties for the site.
Seismic Hazard and Screening Report H.B. Robinson Steam Electric Plant (HBRSEP) Page 10 of 30 Table 2.3.1-1 (Reference 16)Summary of Site Geotechnical Profile for HBRSEP Depth* Shear Compressional Assumed Range Soil/Rock Density Wave Wave Velocity Poisson's (feet) Description (pcf) Velocity (fps) Ratio (fps)Recent Alluvium 0' to 56' RScnt Alluvium 125 1000** 1500 0.33 (Sand and Gravel)Cretaceous Middendorf 56' to 460' (Sands, Silty and Sandy 130 3600 7200 0.33 Clay, Sandstone and Mudstone)Pre-Cambrian Crystalline
> 460' (Granite, Gneiss, Phyllite 170 11200 17500 0.15 Schist)*Measured from EL. 226 ft."The original soil profile data obtained from Figure 2.5.1-2 of the HBR2 Updated FSAR has been adjusted based on recommendations of MACTEC in EC54720-ZOO Attachment A. Figure 2.5.1-2 had a shear wave velocity of 750 fps for the first 30ft of soil (measured from EL. 226 ft);whereas, MACTEC suggested an adjusted value of 1000 fps for the first 70ft of soil (measured from EL. 240 ft). All other soil profile data in Table 2 remains the same as given in Figure 2.5.1-2 of the Updated FSAR.The following description of the general geology at the site is taken directly from URS (Reference 16): "The surficial materials at the HBRSEP site are recent sands or soils developed from the Middendorf.
Because of the high quartz content of the sands and the climatic environment, the surf icial soils may not weather sufficiently to differ considerably from the parent material.Thus, it is nearly impossible to distinguish the recent alluvial soils from the parent Middendorf sand since both the alluvial and weathered soils are derived from the Middendorf.
Only their manner of placement would be different.
From an engineering standpoint, the difference is minor.The subsurface materials encountered in the test holes drilled at the site are completely consistent with recent alluvium and Middendorf Formations encountered throughout the vicinity.
Discontinuities within the strata are sedimentary and no structural deformation is apparent in the Middendorf Formation in the site area.The Middendorf is about 400 ft thick and overlies an eroded, slightly sloping surface of Piedmont crystallines that may be somewhat weathered near the surface.Triassic basins are known in the area; however, it is believed that the likelihood of a Triassic basin at the site is quite small. The basement rock at the site is considered to Seismic Hazard and Screening Report H.B. Robinson Steam Electric Plant (HBRSEP) Page 11 of 30 be Piedmont crystalline since the results of the seismic surveys indicate a high velocity material at a depth consistent with the depth of Piedmont crystallines encountered in wells in the area.In general, the upper alluvial sands and gravels are moderately compact. Layers of compressible material occur in the upper 30 to 50 ft. Because of the quantity of fines in the sand and gravel, it could not be considered free-draining material.
The underlying Middendorf contains generally compact relatively incompressible sands and firm to hard clayey soils. Several strata of cemented sandstone were encountered in the borings at depths of roughly 90 to 100 ft.From a geological standpoint, the Middendorf is considered to be an unconsolidated formation.
From an engineering point of view, however, the materials are firm and compact and would provide good foundation support for the proposed construction.
The materials range in texture from a hard or compact soil to a soft rock." 2.3.2 Development of Base Case Profiles and Nonlinear Material Properties Table 2.3.1-1 shows the recommended shear-wave velocities and unit weights verses depth for the profile. Based on Table 2.3.1-1 and the location of the SSE at surface (Reference 16), the profile consists of 460 ft (140.2 m) of soils and soft rock overlying hard crystalline basement rock.Shear-wave velocities for the profile were based on measurements of compressional-wave velocities (Reference 16), likely through refraction surveys, and assumed Poisson ratios. More recent downhole testing at the nearby ISFSI revised the surf icial alluvium shear-wave velocity from 750 ft/s (228.6 m/s) to 1,000 ft/s (304.8 m/s) (Table 2.3.1-1) and confirmed the deeper shear-wave velocities (Reference 16).For the stiff soils and soft rock of the Cretaceous Middendorf Formation (Table 2.3.1-1), a depth dependent shear-wave velocity gradient, rather than a constant velocity or constant gradient over a 400 ft depth range, was assumed to more accurately, reflect in-situ conditions.
To model a representative velocity gradient for the Middendorf Formation, a 760 m/s (Vs (30 m)) generic profile (Reference
- 2) was adopted and adjusted to reflect the average shear-wave velocity for the Middendorf Formation as specified in Table 2.3.1-1 (Reference 16). The adopted gradient profile is shown in Figure 2.3.2-1.Based on the specified shear-wave velocities, reflecting measured compressional-wave velocities and assumed Poisson ratios, a scale factor of 1.57 was adopted to reflect upper and lower range base-cases.
The scale factor of 1.57 reflects a cr.1 of about 0.35 based on the SPID (Reference
- 2) 10& and 9 0 th fractiles which implies a 1.28 scale factor on op.Using the shear-wave velocities specified in Table 2.3.2-1, three base-profiles were developed using the scale factor of 1.57. The specified shear-wave velocities were taken as the mean or Seismic Hazard and Screening Report H.B. Robinson Steam Electric Plant (HBRSEP)Page 12 of 30 best estimate base-case profile (P1) with lower and upper range base-cases profiles P2 and P3 respectively.
The three base-case profiles P1, P2, and P3, have a mean depth below the SSE of 460 ft (140.2 m) to hard reference rock, randomized
+/- 93 ft (+/- 28.4 m). The base-case profiles (P1, P2, and P3) are shown in Figure 2.3.2-1 and listed in Table 2.3.2-2. The depth randomization reflects +/- 20% of the depth and was based on both borehole and refraction confirmation as well as to provide a realistic broadening of the fundamental resonance rather than reflect actual random variations to basement shear-wave velocities across a footprint.
Vs profiles for Robinson Site Vs (ft/sec)0 1000 2000 3000 4000 5000 6000 7000 8000 9000 10000 0 so 50 100 150 200 1250 is300 350 400 450 500-Profile 1-Profile 2~ 250-Profile 3 Figure 2.3.2-1. Shear-wave velocity profiles for the HBRSEP site.Table 2.3.2-2 Layer thicknesses, depths, and shear-wave velocities (Vs) for 3 profiles, the HBRSEP site Profile 1 Profile 2 Profile 3 thickness(ft) depth (ft) Vs(ftts) thickness(ft) depth (ft) Vs(ft/s) thickness(ft) depth (ft) Vs(if/s)0 1000 0 640 0 1570 5.6 5.6 1000 5.6 5.6 640 5.6 5.6 1570 5.6 11.2 1000 5.6 11.2 640 5.6 11.2 1570 5.6 16.8 1000 5.6 16.8 640 5.6 16.8 1570 5.6 22.4 1000 5.6 22.4 640 5.6 22.4 1570 5.6 28.1 1000 5.6 28.1 640 5.6 28.1 1570 5.6 33.7 1000 5.6 33.7 640 5.6 33.7 1570 5.6 39.3 1000 5.6 39.3 640 5.6 39.3 1570 5.6 44.9 1000 5.6 44.9 640 5.6 44.9 1570 5.6 50.5 1000 5.6 50.5 640 5.6 50.5 1570 5.6 56.1 1000 5.6 56.1 640 5.6 56.1 1570 Seismic Hazard and Screening Report H.B. Robinson Steam Electric Plant (HBRSEP)Page 13 of 30 5.0 61.1 1566 5.0 61.1 1002 5.0 61.1 2458 4.0 65.1 1706 4.0 65.1 1092 4.0 65.1 2679 7.4 72.5 1914 7.4 72.5 1225 7.4 72.5 3005 7.5 80.1 2110 7.5 80.1 1350 7.5 80.1 3312 11.0 91.0 2312 11.0 91.0 1480 11.0 91.0 3630 15.0 106.0 2531 15.0 106.0 1620 15.0 106.0 3974 18.0 124.0 2815 18.0 124.0 1802 18.0 124.0 4420 22.0 146.1 3100 22.0 146.1 1984 22.0 146.1 4867 25.0 171.1 3380 25.0 171.1 2163 25.0 171.1 5306 33.0 204.1 3720 33.0 204.1 2381 33.0 204.1 5840 42.0 246.1 4150 42.0 246.1 2656 42.0 246.1 6515 35.0 281.1 4520 35.0 281.1 2893 35.0 281.1 7096 35.0 316.1 4520 35.0 316.1 2893 35.0 316.1 7096 33.3 349.4 4780 33.3 349.4 3059 33.3 349.4 7504 33.3 382.7 4780 33.3 382.7 3059 33.3 382.7 7504 33.3 416.1 4780 33.3 416.1 3059 33.3 416.1 7504 44.0 460.1 4780 44.0 460.1 3059 44.0 460.1 7504 3280.8 3740.9 9285 3280.8 3740.9 9285 3280.8 3740.9 9285 2.3.2.2 Shear Modulus and Damping Curves No site-specific nonlinear dynamic material properties were determined for the soil and soft rock materials in the initial siting of the HBRSEP. For both the shallow recent alluvium and the stiff sands and soft rock of the Middendorf Formation, EPRI cohesionless soil and Peninsular Range G/Gm,, and hysteretic damping curves we considered appropriate (Reference 2). To more adequately accommodate epistemic uncertainty in nonlinear dynamic material properties, since the relatively high shear-wave velocities coupled with Peninsular Range modulus reduction and hysteretic damping curves results in largely linear response in the Middendorf Formation, a third case comprising a combination of EPRI soil and EPRI rock curves was added. The third case (model M3) consisted of EPRI soil curves for the shallow recent alluvium combined with EPRI rock curves for the Middendorf Formation.
The three cases of nonlinear dynamic material properties was considered to reflect a realistic range in response from largely linear with Peninsular Range curves throughout to significant nonlinearity with the use of EPRI (soil and rock) curves throughout.
The three combinations of EPRI and Peninsular Range G/Gmrx and hysteretic damping curves with a depth distribution based on assuming the Middendorf Formation behaves either as all soil or all soft rock, were considered to equally reflect in-situ conditions (Table 2.3.2-3).2.3.2.3 Kappa For the HBRSEP profile of about 460 ft (140.2 m) of soil and soft rock over hard reference rock, the kappa value of 0.006s for hard rock (Reference
- 2) was combined with the low strain Seismic Hazard and Screening Report H.B. Robinson Steam Electric Plant (HBRSEP) Page 14 of 30 damping in the hysteretic damping curves to give the values listed in Table 2.3.2-3. The low strain kappa values range from 0.008s for the stiffest profile (P3) and EPRI or Peninsular Range curves to 0.019s for the softest profile (P2) combined with EPRI soil and rock curves (Table 2.3.2-3).
The full epistemic uncertainty in overall profile damping has contributions from kappa at low strain in the soil and soft rock but also the wide range in hysteretic damping curves at higher loading levels of significance to design.Table 2.3.2-3 Kappa Values and Weights Used for Site Response Analyses Kaploa(s)Velocity Profile M1, M2 M3 P1 0.009 0.014 P2 0.011 0.019 P3 0.008 0.011 Weights M P1 0.4 P2 0.3 P3 0.3 G/Gm, and Hysteretic Damping Curves M1 0.3 F t'M2 0.3 M3 0.3 2.3.3 Randomization of Base Case Profiles To account for the aleatory variability in dynamic material properties that is expected to occur across a site at the scale of a typical nuclear facility, variability in the assumed shear-wave velocity profiles has been incorporated in the site response calculations.
For the HBRSEP site, random shear wave velocity profiles were developed from the base case profiles shown in Figure 2.3.2-1. Consistent with the discussion in Appendix B of the SPID (Reference 2), the velocity randomization procedure made use of random field models which describe the statistical correlation between layering and shear wave velocity.
The default randomization parameters developed in Toro (1997) for USGS "A" site conditions were used for this site.Thirty random velocity profiles were generated for each base case profile. These random velocity profiles were generated using a natural log standard deviation of 0.25 over the upper 50 ft and 0.15 below that depth. As specified in the SPID (Reference 2), correlation of shear wave velocity between layers was modeled using the footprint correlation model. In the correlation model, a limit of +/- 2 standard deviations about the median value in each layer was assumed for the limits on random velocity fluctuations.
Seismic Hazard and Screening Report H.B. Robinson Steam Electric Plant (HBRSEP) Page 15 of 30 2.3.4 Input Spectra Consistent with the guidance in Appendix B of the SPID (Reference 2), input Fourier amplitude spectra were defined for a single representative earthquake magnitude (M 6.5) using two different assumptions regarding the shape of the seismic source spectrum (single-corner and double-corner).
A range of 11 different input amplitudes (median peak ground accelerations (PGA) ranging from 0.01 to 1.5 g) were used in the site response analyses.
The characteristics of the seismic source and upper crustal attenuation properties assumed for the analysis of the HBRSEP site were the same as those identified in Tables B-4, B-5, B-6 and B-7 of the SPID (Reference
- 2) as appropriate for typical CEUS sites.2.3.5 Methodology To perform the site response analyses for the HBRSEP site, a random vibration theory (RVT)approach was employed.
This process utilizes a simple, efficient approach for computing site-specific amplification functions and is consistent with existing NRC guidance and the SPID (Reference 2). The guidance contained in Appendix B of the SPID (Reference
- 2) on incorporating epistemic uncertainty in shear-wave velocities, kappa, non-linear dynamic properties and source spectra for plants with limited at-site information was followed for the HBRSEP site.2.3.6 Amplification Functions The results of the site response analysis consist of amplification factors (5% damped pseudo absolute response spectra) which describe the amplification (or de-amplification) of hard reference rock motion as a function of frequency and input reference rock amplitude.
The amplification factors are represented in terms of a median amplification value and an associated standard deviation (sigma) for each oscillator frequency and input rock amplitude.
Consistent with the SPID (Reference
- 2) a minimum median amplification value of 0.5 was employed in the present analysis.
Figure 2.3.5-1 illustrates the median and +/- 1 standard deviation in the predicted amplification factors developed for the eleven loading levels parameterized by the median reference (hard rock) peak acceleration (0.01g to 1.50g) for profile P1 and EPRI soil G/Gm, and hysteretic damping curves. The variability in the amplification factors results from variability in shear-wave velocity, depth to hard rock, and modulus reduction and hysteretic damping curves. To illustrate the effects of nonlinearity at the HBRSEP site, Figure 2.3.5-2 shows the corresponding amplification factors developed with Peninsular Range G/Gmý, and hysteretic damping curves resulting in the most linear analyses.
Finally, Figure 2.3.5-3 shows the effects of treating the shallow alluvium with EPRI soil curves and the Middendorf Formation with EPRI rock curves, reflecting the most nonlinear analyses.
Seismic Hazard and Screening Report H.B. Robinson Steam Electric Plant (HBRSEP)Page 16 of 30 C -U C'-U 4"m ca: S CC INPUT MiOTION 0.01G CýINPUT MOTION 0.05G 0 INPUT MOTION 0. LOG-1 1 1 .1 1 C3 INRiT NIOTION4 0.20G I 1 1II I I I T1 INPUT MOTION INPUT 0.40G w -1 0 1a 1 Frequenci (Hz)O 2 10 1 IGO in I1 Frequency (Hz)a2 AMPLIFICATION, ROBINSON, MIPIKI M 6.5, 1 CORNER: PAGE I OF 2 Figure 2.3.5-1 .Example suite of amplification factors (5% damping pseudo absolute acceleration spectra) developed for the mean base-case profile (P1), EPRI soil modulus reduction and hysteretic damping curves (model Ml), and base-case kappa at eleven loading levels of hard rock median peak acceleration values from 0.01 g to 1.50g. M 6.5 and single-comer source model (Reference 2).
Seismic Hazard and Screening Report H.B. Robinson Steam Electric Plant (HBRSEP)Page 17 of 30 id U a-CC-i NPUT /rOTýýO Ný....3-d2o-INPUT NOTIONI.M6O 0 C3 0 0 0: 03 0,-0 INPUT MOTION M.SG INPUT MOTION' 1.25G to -1 to 0 101 Frequency (Hz)12 AMPLIFICATION, ROBINSON, MIPIKI M 6.5, 1 CORNER: PRGE 2 OF 2 Figure 2.3.5-1 .(cont.)
Seismic Hazard and Screening Report H.B. Robinson Steam Electric Plant (HBRSEP)Page 18 of 30 Cl-a: C, 4j* -I~R INPUT MOTIONI 0.OMG INP UT NOTlIr ON .tLOG[INPUT' MOT IICH 0.05G C 0 INPUT rIOT ICt4 O.20G 0-aIjI.I,,.iIaIpIIuI,.iIII.
C -00 4-V-cc 7.-".f~~*'*% *~~*~*--...-INPUT (IOTICH OIOG C2 INPUT NOTIONI 0.40G 10-q to ) o (Hz1 Frequencyl ftz)1 2 10 -3 IQ 0 10 1 Frequency (Hz)10 2 AMIPLIFICATION, ROBINSON, M2PIKI M 6,5, 1 CORNER; PAGE 1 OF 2 Figure 2.3.5-2. Example suite of amplification factors (5% damping pseudo absolute acceleration spectra) developed for the mean base-case profile (P1), Peninsular Range Modulus reduction and hysteretic damping curves (model M2), and base-case kappa at eleven loading levels of hard rock median peak acceleration values from O.01g to 1.50g. M 6.5 and single-comer source model (Reference 2).
Seismic Hazard and Screening Report H.B. Robinson Steam Electric Plant (HBRSEP)Page 19 of 30 C-.ill U ci 0~E a: 0 C-ci~4-, U ci 0~a: 0 C-4-i U* -. 0 0~a: a* K~\., '5-. '~S., 5 '~~5 5 -* --------~iNpur ~ori~ OSOG-S--* J,'\ 'S'55 -* -- 5-~%
- 4 S /: Ifful NOT]CII lOOt;03 0ý03 1 11- 1 111'INU NTO 0,75 INPUT M0TItN 1 .25C 0 vi-0 to U 101 Frequencgj (Hz)AMPLIFICATION, ROBINSON, M2PIK1 M 6.5, 1 CORNER; PAGE 2 OF 2 Figure 2.3.5-2.(cont.)
Seismic Hazard and Screening Report H.B. Robinson Steam Electric Plant (HBRSEP)Page 20 of 30 C 02 U 0.~ 0 0~C a: C-4-,'a U 0* .-. 0 0~~C 0 C aS'a U~2o 0~E a: 0 SINPUT MOTION' O0.G* *~, *-.---*'0 03 0 0 0 0)0~!NPUT MOTION0 LOAG-~ '. -~SINPUT NOTION 0,05G INPUT MiOTION4 0.20G INPUT iROTION 0.40G S2 INPUT MOTION4 0.30G I IIfll I i I B J m 1o -1 to 0 to 1 Frequency (Hz)to-, o0 10w1 Frequency (Hz)10 2 AMPLIFICATION, ROBINSON, M3PIK1 M 6.5, 1 CORNER: PAGE 1 OF 2 Figure 2.3.5-3.Example suite of amplification factors (5% damping pseudo absolute acceleration spectra) developed for the mean base-case profile (P1), EPRI soil (alluvium) and rock (Middendorf Formation) modulus reduction and hysteretic damping curves (model M3), and base-case kappa at eleven loading levels of hard rock median peak acceleration values from O.01g to 1.50g. M 6.5 and single-corner source model (Reference 2).
Seismic Hazard and Screening Report H.B. Robinson Steam Electric Plant (HBRSEP)Page 21 of 30 C -0 C 0~Z C)09 L)C3-9 CI-e, cc INPUT rIOTICNi 0.50G IN~PUT MOTION E1.00GG 0}INPUT MOTICH O.75G 0S 0 C3-2 to 0 I0 1 Frequency (Hz)AMPLIFICATION, ROBINSON, M3PIK1 M 6.5, 1 CORNER; PAGE Z OF 2 Figure 2.3.5-3: (cont.)
Seismic Hazard and Screening Report H.B. Robinson Steam Electric Plant (HBRSEP)Page 22 of 30 2.3.7 Control Point Seismic Hazard Curves The procedure to develop probabilistic site-specific control point hazard curves used in the present analysis follows the methodology described in Section B-6.0 of the SPID (Reference 2).This procedure (referred to as Method 3) computes a site-specific control point hazard curve for a broad range of spectral accelerations given the site-specific bedrock hazard curve and site-specific estimates of soil or soft-rock response and associated uncertainties.
This process is repeated for each of the seven spectral frequencies for which ground motion equations are available.
The dynamic response of the materials below the control point was represented by the frequency-and amplitude-dependent amplification functions (median values and standard deviations) developed and described in the previous section. The resulting control point mean hazard curves for HBRSEP are shown in Figure 2.3.7-1 for the seven spectral frequencies for which ground motion equations are defined. Tabulated values of mean and fractile seismic hazard curves and site response amplification functions are provided in Appendix A.Total Mean Soil Hazard by Spectral Frequency at Robinson 1E-2 1E-3 ----_____-25 Hz-10 Hz 1E-4--5 Hz a -PGA 0 -2.5 Hz 1E-5 ...~-1 Hz-0.5 Hz 1E-6 1E-7 0.01 0.1 1 10 Spectral acceleration (g)Figure 2.3.7-1. Control point mean hazard curves for oscillator frequencies of 0.5, 1, 2.5, 5, 10, 25 and 100 Hz at HBRSEP.2.4 Ground Motion Response Spectrum The control point hazard curves described above have been used to develop uniform hazard response spectra (UHRS) and the ground motion response spectrum (GMRS). The UHRS were obtained through linear interpolation in log-log space to estimate the spectral acceleration at each spectral frequency for the 1 E-4 and 1 E-5 per year hazard levels. Table 2.4-1 shows the UHRS and GMRS accelerations for each of the seven frequencies.
I Seismic Hazard and Screening Report H.B. Robinson Steam Electric Plant (HBRSEP)Page 23 of 30 Table 2.4-1. UHRS and GMRS for HBR2.Freq. (Hz) 10-4 UHRS (g) 10-5 UHRS (g) GMRS 100 4.20E-01 9.17E-01 4.71 E-01 90 4.23E-01 9.31 E-01 4.77E-01 80 4.27E-01 9.48E-01 4.85E-01 70 4.35E-01 9.73E-01 4.97E-01 60 4.54E-01 1.02E+00 5.19E-01 50 4.98E-01 1.11 E+00 5.66E-01 40 5.74E-01 1.25E+00 6.43E-01 35 6.21 E-01 1.35E+00 6.95E-01 30 6.63E-01 1.46E+00 7.50E-01 25 7.23E-01 1.61 E+00 8.21 E-01 20 7.92E-01 1.75E+00 8.97E-01 15 8.09E-01 1.82E+00 9.27E-01 12.5 8.35E-01 1.82E+00 9.36E-01 10 8.52E-61 1.86E+00 9.55E-01 9 8.40E-01 1.84E+00 9.42E-01 8 8.58E-01 1.84E+00 9.49E-01 7 8.98E-01 1.92E+00 9.88E-01 6 8.87E-01 1.95E+00 9.99E-01 5 8.57E-01 1.87E+00 9.61 E-01 4 8.40E-01 1.83E+00 9.39E-01 3.5 7.71 E-01 1.76E+00 8.94E-01 3 6.79E-01 1.59E+00 8.04E-01 2.5 6.08E-01 1.38E+00 7.04E-01 2 5.37E-01 1.30E+00 6.52E-01 1.5 3.97E-01 1.05E+00 5.20E-01 1.25 3.23E-01 8.58E-01 4.23E-01 1 2.26E-01 6.44E-01 3.13E-01 0.9 1.87E-01 5.52E-01 2.67E-01 0.8 1.56E-01 4.69E-01 2.26E-01 0.7 1.31 E-01 3.95E-01 1.90E-01 0.6 1.10E-01 3.25E-01 1.57E-01 0.5 8.86E-02 2.51 E-01 1.22E-01 0.4 7.09E-02 2.01 E-01 9.79E-02 0.35 6.20E-02 1.76E-01 8.57E-02 0.3 5.32E-02 1.51 E-01 7.34E-02 0.25 4.43E-02 1.26E-01 6.12E-02 0.2 3.55E-02 1.OOE-01 4.90E-02 0.15 2.66E-02 7.54E-02 *3.67E-02 0.125 2.22E-02 6.28E-02 3.06E-02 0.1 1.77E-02 5.02E-02 2.45E-02 Seismic Hazard and Screening Report H.B. Robinson Steam Electric Plant (HBRSEP)Page 24 of 30 The 1 E-4 and 1 E-5 UHRS are used to compute the GMRS at the control point and are shown in Figure 2.4-1.Mean Soil UHRS and GMRS at Robinson 2.5 2.1.5 1.5 --4A 0'i 0.5 0.1-1E-5 UHRS--GMRS-1E-4 UHRS 100 1 10 Spectral frequency, Hz Figure 2.4-1. Plots of 1 E-4 and 1 E-5 uniform hazard spectra and GMRS at control point for HBRSEP (5%-damped response spectra).3.0 Safe Shutdown Earthquake Ground Motion The design basis for HBRSEP is identified in the Updated Final Safely Analysis Report (Reference 7).3.1 Description of Spectral Shape and Anchor Point The Safe Shutdown Earthquake (SSE) was developed based on evaluation historic earthquake activity, regional and local geology, and recommendation of Dr. G. W. Housner of the California Institute of Technology.
Only one earthquake of intensity V or greater has ever been recorded within 50 miles of the site.In 1959, an earthquake of intensity V-VI (Modified Mercalli Scale) occurred about 15 miles from the site in the vicinity of McBee, SC. No permanent effects of this shock are noted in the literature or in a geologic reconnaissance, although it is presumed to have been felt at the location of the site. It is estimated that this shock had a magnitude no greater than 4.5 with an epicentral acceleration of well under 0.10 g.
Seismic Hazard and Screening Report H.B. Robinson Steam Electric Plant (HBRSEP)Page 25 of 30 On the basis of historical data, it is expected that the site area could experience a shock in the order of the 1959 McBee shock once during the life of the plant. This shock could be as far distant as in 1959, or perhaps closer. On a conservative basis, Magnitude 4.5 earthquake was selected with an epicentral distance of less than ten miles. This earthquake is the design earthquake and although the probable ground acceleration would be .07 to .09g, a value of 0.1g is used. To provide an adequate margin of safety, a maximum earthquake ground acceleration of 0.2g was selected for the hypothetical SSE.The SSE is defined in terms of a PGA and a design response spectrum.
The SSE response spectra used for the Seismic Class I SSCs for the HBRSEP site have a spectral shape conforming to a Housner curve (Section 2.5 of Reference 7). The horizontal design response spectrum for the SSE was normalized to 0.2g PGA as noted in HBRSEP UFSAR Figure 2.5.2-3 (Reference 7). Table 3.1-1 shows the spectral acceleration values as a function of frequency for the 5% damped horizontal SSE.Table 3.1-i. SSE for HBRSEP (Reference 16)Frequency Spectral (Hz) Acceleration (g)100 0.2 33 0.2 13.33 0.2 10 0.23 8 0.26 5 0.3 4 0.32 3 0.3 1.641 0.24 0.33 0.07 3.2 Control Point Elevation Based on information in Table 1 from URS (Reference 16), the SSE control point elevation is defined at the top of ground surface (i.e., El. 226 feet MSL-NGVD 29, 0 ft depth).4.0 Screening Evaluation In accordance with SPID (Reference
- 2) Section 3, a screening evaluation was performed as described below.
Seismic Hazard and Screening Report H.B. Robinson Steam Electric Plant (HBRSEP) Page 26 of 30 4.1 Risk Evaluation Screening (1 to 10 Hz)In the 1 to 10 Hz part of the response spectrum, the GMRS exceeds the SSE. Therefore, the plant screens in for a risk evaluation.
4.2 High Frequency Screening
(> 10 Hz)For a portion of the range above 10 Hz, the GMRS exceeds the SSE. The high frequency exceedances can be addressed in the risk evaluation discussed in 4.1 above.4.3 Spent Fuel Pool Evaluation Screening (1 to 10 Hz)In the 1 to 10 Hz range of the response spectrum, the GMRS exceeds the SSE. Therefore, the plant screens in for a spent fuel pool evaluation.
5.0 Interim Actions and Assessments As described in Section 4, the GMRS developed in response to the NTTF 2.1: Seismic portion of the 10 CFR 50.54(f) Request for Information of 3/12/2012 exceeds the design basis SSE.The NRC 50.54(f) letter requests: "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." These evaluations and actions are discussed below.Consistent with NRC letter dated February 20, 2014 [Reference 10], the seismic hazard reevaluations presented herein are distinct from the current design and licensing bases of HBRSEP. Therefore, the results do not call into question the operability or functionality of SSCs and are not reportable pursuant to 10 CFR 50.72, "Immediate notification requirements for operating nuclear power reactors," and10 CFR 50.73, "Licensee event report system." 5.1 Expedited Seismic Evaluation Process An expedited seismic evaluation process (ESEP) is being performed at HBRSEP in accordance with the methodology in EPRI 3002000704 as proposed in a letter to NRC dated April 9, 2013 (Reference
- 8) and agreed to by the NRC in a letter dated May 7, 2013 (Reference 9). Duke Energy plans to submit a report on the ESEP to NRC in accordance with the schedule in the April 9, 2013 letter (Reference 8)(prior to the end of December 2014).The ESEP is essentially complete.
An equipment list was developed, inspections were completed and evaluations were performed per EPRI Guidance as described in Reference 3.Insights from the process revealed one case where cabinet anchorage analysis warranted increased capacity for higher than design basis loading, and another case where the seismic capacity of a group of instrument racks could be increased by relatively minor work scope.
Seismic Hazard and Screening Report H.B. Robinson Steam Electric Plant (HBRSEP) Page 27 of 30 Modifications were implemented for two cabinets.
One cabinet (MCC 'A') required modification to achieve seismic capacity greater than two times SSE ( 2 X SSE). The second cabinet was related to the first in configuration and function.
Therefore, a similar modification was implemented for the second electrical cabinet (MCC 'B') to add seismic margin above 2 X SSE.Seismic margin above 2 X SSE was also added to a group of instrument racks (Hagen Racks)by validating the bolting integrity of the top braces (a relatively minor scope of work).5.2 Seismic Risk Estimates The NRC letter (Reference
- 10) also requests that licensees provide an interim evaluation or actions to address the higher seismic hazard relative to the design basis while the expedited approach and risk evaluations are conducted.
In response to that request, NEI letter dated March 12, 2014 (Reference 11), provides seismic core damage risk estimates using the updated seismic hazards for the operating nuclear plants in the Central and Eastern United States. These risk estimates continue to support the following conclusions of the NRC GI-199 Safety/Risk Assessment: "Overall seismic core damage risk estimates are consistent with the Commission's Safety Goal Policy Statement because they are within the subsidiary objective of 1 E-4/year for core damage frequency.
The GI-1 99 Safety/Risk Assessment, based in part on information from the U.S. Nuclear Regulatory Commission's (NRC's) Individual Plant Examination of Extemal Events (IPEEE) program, indicates that no concem exists regarding adequate protection and that the current seismic design of operating reactors provides a safety margin to withstand potential earthquakes exceeding the original design basis." HBRSEP is included in the March 12, 2014 (Reference
- 11) risk estimates.
Using the methodology described in the NEI letter, the seismic core damage risk estimates for all plants were shown to be below 1 E-4/year; thus, the above conclusions apply.5.3 Individual Plant Examination of External Events The IPEEE investigations for HBRSEP followed the methodology for a full scope Seismic Margins Assessment (SMA) presented in NUREG-1407 entitled "Procedural and Submittal Guidance for the Individual Plant Examination of External Events (IPEEE) for Severe Accident Vulnerabilities,".
Methodology from EPRI NP-6041 -SL were applied. Walkdown screening was performed using a 0.30g NUREG/CR-0098 median soil spectrum as a Review Level Earthquake (RLE). The plant level IPEEE High Confidence of Low Probability of Failure (HCLPF) was 0.28g. The HCLPF was dependent on resolution of USI A-46 outlier conditions which have been completed.
Seismic Hazard and Screening Report H.B. Robinson Steam Electric Plant (HBRSEP) Page 28 of 30 5.4 Walkdowns to Address NRC Fukushima NTTF Recommendation 2.3 Walkdowns have been completed for HBRSEP in accordance with the EPRI seismic walkdown guidance (Reference 17); including inaccessible items. Potentially adverse seismic conditions (PASC) found were entered into the corrective action program (CAP) and resolved.
None of the PASC items challenged the operability of the plant. There were no vulnerabilities identified under IPEEE, however, identified enhancements were reviewed and found to be complete.Duke confirmed through the walkdowns that the existing monitoring and maintenance procedures keep the plant consistent with the design basis.6.0 Conclusions In accordance with the 50.54(f) request for information, a seismic hazard and screening evaluation was performed for HBRSEP. A GMRS was developed solely for the purpose of screening for additional evaluations in accordance with the SPID (Reference 2).Based on the results of the screening evaluation, HBRSEP screens in for risk evaluation, a spent fuel pool evaluation and a High Frequency Confirmation.
Seismic Hazard and Screening Report H.B. Robinson Steam Electric Plant (HBRSEP) Page 29 of 30 7.0 References
- 1. United States Nuclear Regulatory Commission (USNRC), E. Leeds and M. Johnson, Letter to All Power Reactor Licensees et al., "Request for Information Pursuant to Title 10 of the Code of Federal Regulations 50.54(f) Regarding Recommendations 2.1, 2.3, and 9.3, of the Near-Term Task Force Review of Insights from the Fukushima Dai-ichi Accident", March 12, 2012.2. Electric Power Research Institute (EPRI), Final Report 1025287, "Seismic Evaluation Guidance:
Screening, Prioritization and Implementation Details (SPID) for the Resolution of Fukushima Near-Term Task Force Recommendation 2.1: Seismic", February 2013.3. Electric Power Research Institute (EPRI), Final Report No. 3002000704, "Seismic Evaluation Guidance:
Augmented Approach for the Resolution of Fukushima Near-Term Task Force Recommendation 2.1: Seismic", May 2013.4. United States Nuclear Regulatory Commission (USNRC), NUREG-2115, Department of Energy/Office of Nuclear Energy (DOE/NE)-0140, EPRI 1021097, "Central and Eastern United States Seismic Source Characterization for Nuclear Facilities", 6 Volumes, 2012.5. Electric Power Research Institute (EPRI), Final Report No. 3002000717, "EPRI (2004, 2006) Ground-Motion Model (GMM) Review Project", June 2013.6. United States Nuclear Regulatory Commission (USNRC), Regulatory Guide (RG) 1.208,"A Performance-Based Approach to Define the Site-Specific Earthquake Ground Motion", March 2007.7. Progress Energy, "H.B. Robinson Nuclear Power Plant Unit 2 Updated Final Safety Analysis Report", Revision 24.8. Nuclear Energy Institute (NEI), A. Pietrangelo, Letter to D. Skeen of the USNRC,"Proposed Path Forward for NTTF Recommendation 2.1: Seismic Reevaluations", April 9, 2013 (ML13101 A379).9. United States Nuclear Regulatory Commission (USNRC), E. Leeds, Letter to J. Pollock of NEI, "Electric Power Research Institute Final Draft Report XXXXXX, 'Seismic Evaluation Guidance:
Augmented Approach for the Resolution of Fukushima Near-Term Task Force Recommendation 2.1: Seismic,'
as an Acceptable Alternative to the March 12, 2012, Information Request for Seismic Reevaluations", May 7, 2013.10. United States Nuclear Regulatory Commission (USNRC), E. Leeds, Letter to All Power Reactor Licensees and Holders of Construction Permits, "Supplemental Information Related to Request for Information Pursuant to Title 10 of the Code of Federal Regulations 50.54(f) Regarding Seismic Hazard Reevaluations for Recommendation 2.1 Seismic Hazard and Screening Report H.B. Robinson Steam Electric Plant (HBRSEP) Page 30 of 30 of the Near-Term Task Force Review of Insights From the Fukushima Dai-lchi Accident", February 20, 2014 (ML14030A046).
- 11. Nuclear Energy Institute (NEI), A. Pietrangelo, Letter to D. Skeen of the USNRC,"Seismic Core Damage Risk Estimates Using the Updated Seismic Hazards for the Operating Nuclear Plants in the Central and Eastern United States", March 12, 2014.12. W.H. Bakun and M.G. Hopper (2004), "Magnitudes and Locations of the 1811-1812 New Madrid, Missouri, and the 1886 Charleston, South Carolina, Earthquakes," Bulletin of the Seismological Society of America, 94, 64-75 13. Review of EPRI 1021097 Earthquake Catalog for RIS Earthquakes in the Southeastern U. S. and Earthquakes in South Carolina Near the Time of the 1886 Charleston Earthquake Sequence, transmitted by letter from J. Richards to R. McGuire on March 5, 2014.14. McGuire, R.K. (2004). Seismic Hazard and Risk Analysis, Earthquake Eng. Res. Inst., Monograph MNO-10.15. Appendix of: Silva, W.J., Abrahamson, N., Toro, G., and Costantino, C. (1997)."Description and validation of the stochastic ground motion model", Report Submitted to Brookhaven National Laboratory, Associated Universities, Inc., Upton, New York 11973, Contract No. 770573.16. Site Geologic Conditions for H.B Robinson Steam Electric Plant, Unit 2, Letter Rept. PE-RNP-A07-12128 dated July 9, 2012, transmitted by letter from B. Alumbaugh to C.Albers dated July 9, 2012.17. Electric Power Research Institute (EPRI), Final Report No. 1025286, "Seismic Walkdown Guidance for Resolution of Fukushima Near-Term Task Force Recommendation 2.3: Seismic", June 2012.
Seismic Hazard and Screening Report H.B. Robinson Steam Electric Plant (HBRSEP)Page A-1 Appendix A (Additional Tables)Table A-ia. Mean and Fractile Seismic Hazard Curves for PGA at Robinson AMPS(g) MEAN 0.05 0.16 0.50 0.84 0.95 0.0005 4.87E-02 3.68E-02 4.31 E-02 4.90E-02 5.50E-02 5.83E-02 0.001 4.43E-02 2.92E-02 3.79E-02 4.50E-02 5.12E-02 5.50E-02 0.005 2.44E-02 1.21 E-02 1.82E-02 2.42E-02 3.09E-02 3.68E-02 0.01 1.56E-02 7.55E-03 1.07E-02 1.51 E-02 2.01 E-02 2.68E-02 0.015 1.15E-02 5.42E-03 7.45E-03 1.08E-02 1.46E-02 2.13E-02 0.03 6.20E-03 2.64E-03 3.68E-03 5.66E-03 8.12E-03 1.29E-02 0.05 3.72E-03 1.29E-03 1.92E-03 3.28E-03 5.27E-03 8.12E-03 0.075 2.38E-03 6.09E-04 1.02E-03 2.01 E-03 3.63E-03 5.66E-03 0.1 1.66E-03 3.28E-04 5.83E-04 1.31 E-03 2.68E-03 4.31E-03 0.15 9.09E-04 1.20E-04 2.22E-04 6.09E-04 1.60E-03 2.76E-03 0.3 2.33E-04 1.42E-05 2.96E-05 9.93E-05 4.01 E-04 9.24E-04 0.5 6.44E-05 1.95E-06 4.98E-06 2.13E-05 9.24E-05 2.68E-04 0.75 1.94E-05 3.33E-07 1.07E-06 6.17E-06 2.60E-05 7.45E-05 1. 7.51 E-06 9.93E-08 3.68E-07 2.32E-06 1.04E-05 2.80E-05 1.5 1.76E-06 1.82E-08 8.12E-08 5.05E-07 2.64E-06 6.73E-06 3. 1.29E-07 6.73E-10 3.28E-09 3.05E-08 2.07E-07 5.50E-07 5. 1.90E-08 1.32E-10 2.84E-10 3.19E-09 2.64E-08 8.35E-08 7.5 3.92E-09 1.01E-10 1.32E-10 5.27E-10 4.63E-09 1.77E-08 10. 1.19E-09 9.37E-11 1.23E-10 2.01E-10 1.32E-09 5.58E-09 Table A-lb. Mean and Fractile Seismic Hazard Curves for 25 Hz at Robinson AMPS(g) MEAN 0.05 0.16 0.50 0.84 0.95 0.0005 4.98E-02 3.95E-02 4.43E-02 5.05E-02 5.50E-02 5.83E-02 0.001 4.65E-02 3.42E-02 4.07E-02 4.70E-02 5.27E-02 5.58E-02 0.005 2.94E-02 1.69E-02 2.32E-02 2.92E-02 3.57E-02 4.13E-02 0.01 2.07E-02 1.13E-02 1.53E-02 2.01 E-02 2.53E-02 3.28E-02 0.015 1.62E-02 8.47E-03 1.16E-02 1.55E-02 1.98E-02 2.76E-02 0.03 9.73E-03 4.83E-03 6.54E-03 9.11 E-03 1.23E-02 1.79E-02 0.05 6.19E-03 2.80E-03 3.79E-03 5.75E-03 8.23E-03 1.18E-02 0.075 4.11E-03 1.55E-03 2.25E-03 3.73E-03 5.75E-03 8.12E-03 0.1 2.98E-03 9.24E-04 1.46E-03 2.68E-03 4.37E-03 6.26E-03 0.15 1.80E-03 3.84E-04 6.73E-04 1.51 E-03 2.88E-03 4.25E-03 0.3 6.20E-04 5.05E-05 1.11E-04 3.95E-04 1.11E-03 1.98E-03 0.5 2.33E-04 1.02E-05 2.46E-05 1.13E-04 4.13E-04 8.72E-04 0.75 9.18E-05 3.63E-06 8.47E-06 3.73E-05 1.51 E-04 3.63E-04 1. 4.30E-05 1.87E-06 4.13E-06 1.57E-05 6.64E-05 1.67E-04 1.5 1.27E-05 6.09E-07 1.38E-06 4.50E-06 1.95E-05 4.70E-05 3. 1.13E-06 2.60E-08 8.60E-08 4.77E-07 1.95E-06 4.13E-06 5. 2.10E-07 1.05E-09 6.45E-09 7.55E-08 3.95E-07 8.47E-07 7.5 7.50E-08 1.53E-10 7.55E-10 1.21 E-08 1.32E-07 3.57E-07 10. 4.03E-08 1.32E-10 2.13E-10 2.84E-09 6.93E-08 2.07E-07 Seismic Hazard and Screening Report H.B. Robinson Steam Electric Plant (HBRSEP)Page A-2 Table A-ic. Mean and Fractile Seismic Hazard Curves for 10 Hz at Robinson AMPS(g) MEAN 0.05 0.16 0.50 0.84 0.95 0.0005 5.11E-02 4.25E-02 4.56E-02 5.12E-02 5.66E-02 5.91 E-02 0.001 4.91 E-02 4.01 E-02 4.37E-02 4.90E-02 5.42E-02 5.75E-02 0.005 3.40E-02 2.29E-02 2.76E-02 3.42E-02 4.01 E-02 4.43E-02 0.01 2.43E-02 1.46E-02 1.84E-02 2.42E-02 3.01 E-02 3.47E-02 0.015 1.89E-02 1.08E-02 1.38E-02 1.87E-02 2.35E-02 2.84E-02 0.03 1.13E-02 6.OOE-03 7.77E-03 1.08E-02 1.44E-02 1.84E-02 0.05 7.18E-03 3.57E-03 4.77E-03 6.83E-03 9.37E-03 1.21 E-02 0.075 4.85E-03 2.19E-03 3.01 E-03 4.56E-03 6.54E-03 8.60E-03 0.1 3.61 E-03 1.46E-03 2.1OE-03 3.37E-03 5.05E-03 6.64E-03 0.15 2.29E-03 7.34E-04 1.15E-03 2.07E-03 3.42E-03 4.63E-03 0.3 8.80E-04 1.64E-04 2.96E-04 6.93E-04 1.46E-03 2.25E-03 0.5 3.44E-04 3.90E-05 7.55E-05 2.22E-04 6.OOE-04 1.08E-03 0.75 1.38E-04 9.51 E-06 2.04E-05 7.23E-05 2.42E-04 4.90E-04 1. 6.63E-05 3.14E-06 7.23E-06 3.05E-05 1.11 E-04 2.49E-04 1.5 2.06E-05 6.45E-07 1.62E-06 8.12E-06 3.33E-05 7.89E-05 3. 2.01 E-06 4.98E-08 1.51 E-07 6.54E-07 3.28E-06 8.OOE-06 5. 3.02E-07 5.66E-09 1.84E-08 9.51 E-08 5.12E-07 1.23E-06 7.5 6.66E-08 6.00E-10 2.46E-09 2.07E-08 1.15E-07 2.76E-07 10. 2.39E-08 1.74E-10 6.09E-10 6.93E-09 4.07E-08 1.05E-07 Table A-id. Mean and Fractile Seismic Hazard Curves for 5 Hz at Robinson AMPS(g) MEAN 0.05 0.16 0.50 0.84 0.95 0.0005 5.15E-02 4.31E-02 4.63E-02 5.20E-02 5.66E-02 6.OOE-02 0.001 5.02E-02 4.13E-02 4.50E-02 5.05E-02 5.50E-02 5.83E-02 0.005 3.70E-02 2.49E-02 2.96E-02 3.73E-02 4.43E-02 4.83E-02 0.01 2.70E-02 1.60E-02 2.04E-02 2.68E-02 3.37E-02 3.73E-02 0.015 2.1OE-02 1.16E-02 1.53E-02 2.07E-02 2.68E-02 3.05E-02 0.03 1.20E-02 6.26E-03 8.35E-03 1.16E-02 1.57E-02 1.87E-02 0.05 7.36E-03 3.73E-03 4.98E-03 7.13E-03 9.79E-03 1.20E-02 0.075 4.85E-03 2.29E-03 3.09E-03 4.63E-03 6.54E-03 8.12E-03 0.1 3.56E-03 1.53E-03 2.16E-03 3.37E-03 4.98E-03 6.17E-03 0.15 2.26E-03 7.77E-04 1.20E-03 2.1OE-03 3.33E-03 4.31E-03 0.3 8.86E-04 1.82E-04 3.28E-04 7.34E-04 1.44E-03 2.13E-03 0.5 3.51 E-04 4.63E-05 8.85E-05 2.39E-04 6.09E-04 1.04E-03 0.75 1.41 E-04 1.21 E-05 2.46E-05 7.66E-05 2.42E-04 4.90E-04 1. 6.71E-05 3.90E-06 8.47E-06 3.09E-05 1.11E-04 2.53E-04 1.5 2.1OE-05 6.OOE-07 1.49E-06 7.66E-06 3.23E-05 8.35E-05 3. 2.09E-06 1.77E-08 6.73E-08 5.66E-07 3.09E-06 8.12E-06 5. 3.05E-07 1.46E-09 8.23E-09 6.54E-08 4.77E-07 1.27E-06 7.5 6.02E-08 2.84E-10 1.29E-09 1.11E-08 9.37E-08 2.68E-07 10. 1.87E-08 1.42E-10 3.47E-10 3.01 E-09 2.76E-08 8.47E-08 Seismic Hazard and Screening Report H.B. Robinson Steam Electric Plant (HBRSEP)Page A-3 Table A-i e. Mean and Fractile Seismic Hazard Curves for 2.5 Hz at Robinson AMPS(g) MEAN 0.05 0.16 0.50 0.84 0.95 0.0005 5.05E-02 4.19E-02 4.50E-02 5.05E-02 5.58E-02 5.91 E-02 0.001 4.76E-02 3.68E-02 4.13E-02 4.77E-02 5.35E-02 5.75E-02 0.005 2.95E-02 1.60E-02 2.04E-02 2.92E-02 3.90E-02 4.43E-02 0.01 1.95E-02 8.85E-03 1.20E-02 1.87E-02 2.72E-02 3.23E-02 0.015 1.43E-02 5.91 E-03 8.12E-03 1.36E-02 2.04E-02 2.53E-02 0.03 7.49E-03 2.64E-03 3.84E-03 6.93E-03 1.11E-02 1.42E-02 0.05 4.36E-03 1.31 E-03 2.1OE-03 4.01E-03 6.64E-03 8.60E-03 0.075 2.79E-03 7.03E-04 1.23E-03 2.53E-03 4.31 E-03 5.75E-03 0.1 2.01 E-03 4.19E-04 7.89E-04 1.79E-03 3.23E-03 4.37E-03 0.15 1.23E-03 1.87E-04 3.84E-04 1.02E-03 2.07E-03 2.96E-03 0.3 4.36E-04 3.52E-05 8.OOE-05 2.84E-04 7.89E-04 1.38E-03 0.5 1.60E-04 8.12E-06 1.90E-05 7.55E-05 2.80E-04 6.OOE-04 0.75 6.03E-05 2.16E-06 5.20E-06 2.16E-05 9.51 E-05 2.49E-04 1. 2.73E-05 7.77E-07 1.90E-06 8.23E-06 3.79E-05 1.13E-04 1.5 7.79E-06 1.55E-07 4.13E-07 1.90E-06 9.11 E-06 3.05E-05 3. 6.43E-07 6.17E-09 2.07E-08 1.31 E-07 7.03E-07 2.19E-06 5. 8.57E-08 4.56E-10 1.64E-09 1.51E-08 1.04E-07 3.19E-07 7.5 1.73E-08 1.40E-10 2.68E-10 2.39E-09 2.07E-08 7.23E-08 10. 5.66E-09 1.08E-10 1.42E-10 6.36E-10 6.54E-09 2.49E-08 Table A-If. Mean and Fractile Seismic Hazard Curves for 1 Hz at Robinson AMPS(g) MEAN 0.05 0.16 0.50 0.84 0.95 0.0005 3.82E-02 2.16E-02 2.80E-02 3.90E-02 4.83E-02 5.27E-02 0.001 2.92E-02 1.38E-02 1.87E-02 2.88E-02 3.95E-02 4.50E-02 0.005 1.05E-02 3.47E-03 5.27E-03 9.93E-03 1.55E-02 1.95E-02 0.01 5.96E-03 1.53E-03 2.60E-03 5.42E-03 9.24E-03 1.21 E-02 0.015 4.14E-03 8.47E-04 1.57E-03 3.68E-03 6.73E-03 8.98E-03 0.03 2.02E-03 2.25E-04 5.20E-04 1.67E-03 3.52E-03 5.12E-03 0.05 1.09E-03 6.45E-05 1.77E-04 8.OOE-04 2.01 E-03 3.09E-03 0.075 6.30E-04 2.01 E-05 6.45E-05 4.07E-04 1.21 E-03 1.98E-03 0.1 4.12E-04 8.35E-06 2.88E-05 2.32E-04 8,12E-04 1.42E-03 0.15 2.15E-04 2.32E-06 8.60E-06 9.51E-05 4.19E-04 8.35E-04 0.3 5.87E-05 2.76E-07 1.10E-06 1.57E-05 1.01 E-04 2.64E-04 0.5 1.90E-05 6.64E-08 2.88E-07 3.52E-06 2.80E-05 8.85E-05 0.75 6.82E-06 2.22E-08 1.02E-07 1.04E-06 8.72E-06 3.14E-05 1. 3.07E-06 1.01 E-08 4.83E-08 4.31 E-07 3.63E-06 1.38E-05 1.5 8.99E-07 2.96E-09 1.49E-08 1.23E-07 1.01 E-06 3.90E-06 3. 8.93E-08 3.79E-10 1.62E-09 1.31 E-08 1.05E-07 3.95E-07 5. 1.57E-08 1.42E-10 3.19E-10 2.19E-09 1.84E-08 7.03E-08 7.5 4.08E-09 1.15E-10 1.44E-10 5.42E-10 4.37E-09 1.77E-08 10. 1.56E-09 1.01E-10 1.32E-10 2.35E-10 1.60E-09 6.73E-09 Seismic Hazard and Screening Report H.B. Robinson Steam Electric Plant (HBRSEP)Page A-4 Table A-ig. Mean and Fractile Seismic Hazard Curves for 0.5 Hz at Robinson AMPS(g) MEAN 0.05 0.16 0.50 0.84 0.95 0.0005 2.14E-02 1.25E-02 1.60E-02 2.1OE-02 2.68E-02 3.09E-02 0.001 1.40E-02 7.45E-03 9.93E-03 1.36E-02 1.79E-02 2.16E-02 0.005 4.81 E-03 1.60E-03 2.53E-03 4.50E-03 7.13E-03 9.11E-03 0.01 2.72E-03 6.OOE-04 1.11 E-03 2.35E-03 4.37E-03 6.OOE-03 0.015 1.78E-03 2.84E-04 5.91E-04 1.44E-03 2.96E-03 4.37E-03 0.03 7.00E-04 5.75E-05 1.49E-04 4.77E-04 1.23E-03 2.13E-03 0.05 2.99E-04 1.36E-05 4.01E-05 1.57E-04 5.42E-04 1.08E-03 0.075 1.40E-04 3.90E-06 1.20E-05 5.66E-05 2.46E-04 5.66E-04 0.1 7.85E-05 1.55E-06 4.77E-06 2.46E-05 1.29E-04 3.42E-04 0.15 3.30E-05 3.84E-07 1.20E-06 6.93E-06 4.63E-05 1.53E-04 0.3 6.63E-06 2.76E-08 1.01 E-07 6.83E-07 6.26E-06 3.01 E-05 0.5 1.85E-06 3.05E-09 1.38E-08 1.25E-07 1.31 E-06 7.55E-06 0.75 6.36E-07 5.12E-10 2.60E-09 3.23E-08 3.79E-07 2.39E-06 1. 2.89E-07 2.01E-10 8.12E-10 1.23E-08 1.60E-07 1.08E-06 1.5 9.15E-08 1.32E-10 2.10E-10 3.01 E-09 4.77E-08 3.42E-07 3. 1.15E-08 1.01E-10 1.32E-10 3.09E-10 5.27E-09 4.37E-08 5. 2.25E-09 9.11E-11 1.011E-10 1.42E-10 9.79E-10 8.23E-09 7.5 5.70E-10 9.11E-11 1.01E-10 1.32E-10 2.92E-10 1.98E-09 10. 2.04E-10 9.11E-11 1.01E-10 1.32E-10 1.67E-10 7.34E-10 Seismic Hazard and Screening Report H.B. Robinson Steam Electric Plant (HBRSEP)Page A-5 Table A-2. Amplification Functions for HBRSEP Median Sigma Median Sigma Median Sigma Median Sigma PGA AF In(AF) 25 Hz AF In(AF) 10 Hz AF In(AF) 5 Hz AF In(AF)1.OOE-02 2.78E+00 1.01 E-01 1.30E-02 2.52E+00 1.05E-01 1.90E-02 2.58E+00 1.61 E-01 2.09E-02 3.27E+00 1.93E-01 4.95E-02 2.31E+00 1.13E-01 1.02E-01 1.83E+00 1.61E-01 9.99E-02 2.30E+00 1.84E-01 8.24E-02 3.07E+00 2.08E-01 9.64E-02 2.04E+00 1.20E-01 2.13E-01 1.59E+00 1.81 E-01 1.85E-01 2.15E+00 1.96E-01 1.44E-01 2.91 E+00 2.15E-01 1.94E-01 1.74E+00 1.37E-01 4.43E-01 1.30E+00 2.04E-01 3.56E-01 1.91 E+00 2.23E-01 2.65E-01 2.65E+00 2.33E-01 2.92E-01 1.56E+00 1.44E-01 6.76E-01 1.12E+00 2.19E-01 5.23E-01 1.73E+00 2.38E-01 3.84E-01 2.46E+00 2.38E-01 3.91 E-01 1.42E+00 1.56E-01 9.09E-01 9.94E-01 2.35E-01 6.90E-01 1.58E+00 2.49E-01 5.02E-01 2.30E+00 2.46E-01 4.93E-01 1.31 E+00 1.71 E-01 1.15E+00 8.93E-01 2.50E-01 8.61E-01 1.46E+00 2.59E-01 6.22E-01 2.17E+00 2.52E-01 7.41E-01 1.12E+00 1.97E-01 1.73E+00 7.19E-01 2.74E-01 1.27E+00 1.24E+00 2.78E-01 9.13E-01 1.92E+00 2.74E-01 1.01E+00 9.82E-01 2.16E-01 2.36E+00 6.01E-01 2.93E-01 1.72E+00 1.07E+00 2.98E-01 1.22E+00 1.70E+00 2.93E-01 1.28E+00 8.77E-01 2.45E-01 3.01E+00 5.14E-01 3.14E-01 2.17E+00 9.48E-01 3.36E-01 1.54E+00 1.52E+00 3.36E-01 1.55E+00 8.02E-01 2.63E-01 3.63E+00 5.OOE-01 3.30E-01 2.61 E+00 8.56E-01 3.58E-01 1.85E+00 1.39E+00 3.69E-01 Median Sigma Median Sigma Median Sigma 2.5 Hz AF In(AF) 1 Hz AF In(AF) 0.5 Hz AF In(AF)2.18E-02 2.94E+00 2.03E-01 1.27E-02 1.83E+00 1.54E-01 8.25E-03 1.43E+00 1.65E-01 7.05E-02 2.92E+00 1.95E-01 3.43E-02 1.95E+00 1.67E-01 1.96E-02 1.48E+00 1.66E-01 1.18E-01 2.83E+00 1.98E-01 5.51E-02 2.04E+00 1.86E-01 3.02E-02 1.50E+00 1.69E-01 2.12E-01 2.66E+00 2.30E-01 9.63E-02 2.15E+00 2.71 E-01 5.11E-02 1.54E+00 1.89E-01 3.04E-01 2.53E+00 2,37E-01 1.36E-01 2,18E+00 3.35E-01 7.1OE-02 1.58E+00 2.06E-01 3.94E-01 2.42E+00 2.55E-01 1.75E-01 2.17E+00 3.59E-01 9.06E-02 1.63E+00 2.38E-01 4.86E-01 2.30E+00 2.78E-01 2.14E-01 2.13E+00 3.85E-01 1.10E-01 1.64E+00 2.51 E-01 7.09E-01 2.11E+00 3.11E-01 3.1OE-01 2.09E+00 4.01E-01 1.58E-01 1.70E+00 2.87E-01 9.47E-01 1.96E+00 3.51E-01 4.12E-01 2.11E+00 4.03E-01 2.09E-01 1.74E+00 3.13E-01 1.19E+00 1.85E+00 3.81E-01 5,18E-01 2.12E+00 4.03E-01 2.62E-01 1.77E+00 3.25E-01 1.43E+00 1.81E+00 3.78E-01 6.19E-01 2.14E+00 3.96E-01 3.12E-01 1.80E+00 3.30E-01 Seismic Hazard and Screening Report H.B. Robinson Steam Electric Plant (HBRSEP)Page A-6 Table A2-bl. Median AFs and sigmas for Model 1, Profile 1, for 2 PGA levels.M1 P1 K1 Rock PGA=0.292 M1 P1 K1 PGA=1.28 Freq. med. Freq. med.(Hz) SoilSA AF sigma ln(AF) (Hz) Soil SA AF sigma ln(AF)100.0 0.485 1.658 0.116 100.0 1.056 0.824 0.281 87.1 0.487 1.620 0.117 87.1 1.057 0.797 0.281 75.9 0.491 1.553 0.119 75.9 1.058 0.752 0.281 66.1 0.497 1.429 0.122 66.1 1.060 0.672 0.282 57.5 0.509 1.238 0.129 57.5 1.063 0.556 0.283 50.1 0.531 1.067 0.141 50.1 1.068 0.457 0.285 43.7 0.562 0.954 0.156 43.7 1.076 0.390 0.289 38.0 0.601 0.932 0.173 38.0 1.088 0.365 0.295 33.1 0.642 0.948 0.186 33.1 1.105 0.357 0.300 28.8 0.688 1.021 0.203 28.8 1.129 0.371 0.304 25.1 0.734 1.087 0.215 25.1 1.164 0.387 0.315 21.9 0.778 1.216 0.221 21.9 1.207 0.429 0.330 19.1 0.815 1.299 0.223 19.1 1.259 0.462 0.335 16.6 0.846 1.410 0.213 16.6 1.308 0.508 0.334 14.5 0.871 1.527 0.196 14.5 1.365 0.563 0.338 12.6 0.916 1.658 0.226 12.6 1.433 0.616 0.337 11.0 0.943 1.756 0.249 11.0 1.520 0.678 0.343 9.5 0.992 1.941 0.253 9.5 1.613 0.762 0.367 8.3 0.977 2.079 0.251 8.3 1.724 0.892 0.379 7.2 0.999 2.277 0.228 7.2 1.821 1.016 0.378 6.3 0.954 2.320 0.221 6.3 1.912 1.146 0.395 5.5 0.902 2.303 0.217 5.5 1.939 1.227 0.384 4.8 0.940 2.462 0.257 4.8 1.947 1.270 0.370 4.2 1.028 2.780 0.276 4.2 1.986 1.346 0.386 3.6 1.065 2.966 0.216 3.6 2.083 1.461 0.406 3.2 1.041 3.085 0.160 3.2 2.199 1.648 0.413 2.8 1.015 3.175 0.172 2.8 2.338 1.857 0.400 2.4 1.007 3.422 0.148 2.4 2.380 2.062 0.412 2.1 0.932 3.487 0.174 2.1 2.401 2.300 0.416 1.8 0.772 3.236 0.180 1.8 2.429 2.617 0.406 1.6 0.579 2.804 0.219 1.6 2.319 2.898 0.358 1.4 0.432 2.437 0.188 1.4 2.096 3.062 0.303 1.2 0.325 2.085 0.163 1.2 1.828 3.054 0.245 1.0 0.247 1.759 0.114 1.0 1.465 2.734 0.225 0.91 0.198 1.555 0.085 0.91 1.119 2.315 0.233 0.79 0.168 1.463 0.098 0.79 0.870 2.008 0.225 0.69 0.147 1.439 0.116 0.69 0.698 1.826 0.196 0.60 0.128 1.448 0.138 0.60 0.571 1.732 0.176 0.52 0.110 1.465 0.165 0.52 0.467 1.677 0.177 0.46 0.092 1.468 0.187 0.46 0.376 1.629 0.188 0.10 0.003 1.218 0.043 0.10 0.011 1.236 0.055 Seismic Hazard and Screening Report H.B. Robinson Steam Electric Plant (HBRSEP)Page A-7 Table A2-b2. Median AFs and sigmas for Model 2, Profile 1, for 2 PGA levels.M2PIK1 PGA=0.292 M2PIK1 PGA=1.28 Freq. med. Freq. med.(Hz) SoilSA AF sigma In(AF) (Hz) Soil SA AF sigma In(AF)100.0 0.568 1.944 0.128 100.0 1.437 1.122 0.242 87.1 0.573 1.905 0.130 87.1 1.441 1.087 0.243 75.9 0.580 1.837 0.132 75.9 1.447 1.028 0.245 66.1 0.594 1.710 0.137 66.1 1.456 0.923 0.248 57.5 0.623 1.514 0.147 57.5 1.472 0.770 0.253 50.1 0.673 1.353 0.168 50.1 1.502 0.643 0.265 43.7 0.739 1.255 0.190 43.7 1.546 0.560 0.280 38.0 0.809 1.256 0.206 38.0 1.602 0.537 0.296 33.1 0.880 1.298 0.223 33.1 1.675 0.541 0.311 28.8 0.935 1.387 0.240 28.8 1.764 0.580 0.327 25.1 1.000 1.481 0.248 25.1 1.865 0.620 0.348 21.9 1.049 1.641 0.262 21.9 1.975 0.703 0.367 19.1 1.078 1.718 0.260 19.1 2.098 0.770 0.373 16.6 1.104 1.841 0.240 16.6 2.233 0.867 0.378 14.5 1.109 1.944 0.215 14.5 2.338 0.965 0.381 12.6 1.142 2.066 0.224 12.6 2.456 1.055 0.379 11.0 1.156 2.153 0.265 11.0 2.616 1.167 0.370 9.5 1.160 2.270 0.254 9.5 2.679 1.265 0.342 8.3 1.105 2.351 0.226 8.3 2.638 1.365 0.351 7.2 1.127 2.568 0.184 7.2 2.765 1.543 0.365 6.3 1.045 2.543 0.208 6.3 2.842 1.704 0.328 5.5 1.012 2.584 0.211 5.5 2.828 1.790 0.269 4.8 1.091 2.856 0.245 4.8 2.764 1.803 0.289 4.2 1.180 3.194 0.248 4.2 2.809 1.904 0.364 3.6 1.146 3.192 0.217 3.6 2.902 2.035 0.371 3.2 1.089 3.227 0.197 3.2 2.982 2.234 0.351 2.8 1.050 3.286 0.198 2.8 3.029 2.407 0.316 2.4 1.021 3.471 0.163 2.4 3.116 2.699 0.294 2.1 0.903 3.380 0.196 2.1 3.066 2.937 0.269 1.8 0.718 3.011 0.195 1.8 2.927 3.153 0.231 1.6 0.534 2.589 0.217 1.6 2.471 3.089 0.234 1.4 0.403 2.274 0.184 1.4 1.989 2.907 0.263 1.2 0.308 1.974 0.166 1.2 1.540 2.573 0.270 1.0 0.237 1.688 0.116 1.0 1.136 2.120 0.230 0.91 0.192 1.508 0.083 0.91 0.868 1.795 0.181 0.79 0.164 1.431 0.096 0.79 0.705 1.626 0.157 0.69 0.144 1.415 0.116 0.69 0.594 1.555 0.152 0.60 0.127 1.431 0.138 0.60 0.506 1.535 0.159 0.52 0.109 1.451 0.166 0.52 0.426 1.531 0.179 0.46 0.091 1.457 0.188 0.46 0.350 1.518 0.197 0.10 0.003 1.215 0.045 0.10 0.011 1.211 0.056 Tables A2-bl and A2-b2 are tabular versions of the typical amplification factors provided in Figures 2.3.5-1 and 2.3.5-2. Values are provided for two input motion levels at approximately 104 and 10- mean annual frequency of exceedance.