ML12312A031

Licensing Basis for the Protected Service Water System - Responses to Request for Additional Information - Supplement 3

ML12312A031
Person / Time
Site:	Oconee
Issue date:	11/02/2012
From:	Gillespie T Duke Energy Carolinas
To:	Document Control Desk, Office of Nuclear Reactor Regulation
References
Download: ML12312A031 (29)

Text

T. PRESTON GILLESPIE, JR.

Vice President P'-*Enlergy Oconee Nuclear Station Duke Energy ON01 VP / 7800 Rochester Hwy.

Seneca, SC 29672 864-873-4478 10 CER 50.90 864-873-4208 fax T.Gillespie@duke-energy.com November 2, 2012 Document Control Desk U.S. Nuclear Regulatory Commission Washington, DC 20555-0001

Subject:

Duke Energy Carolinas, LLC Oconee Nuclear Station, Units 1, 2, and 3 Docket Numbers 50-269, 50-270, and 50-287, Renewed Operating Licenses DPR-38, DPR-47, and DPR-55 Licensing Basis for the Protected Service Water System - Responses to Request for Additional Information - Supplement 3

References:

1. Letter from John Boska, Senior Project Manager, Division of Operating Reactor Licensing, Office of Nuclear Reactor Regulation, U.S. Nuclear Regulatory Commission, to T. Preston Gillespie, Vice President, Oconee Nuclear Station, Duke Energy Carolinas, LLC, "Request for Additional Information (RAI) Regarding the License Amendment Requests (LARs) for the Licensing Basis for the Protected Service Water System," June 11, 2012.

2. Letter from T. Preston Gillespie, Vice President, Oconee Nuclear Station, Duke Energy Carolinas, LLC, to the U.S. Nuclear Regulatory Commission, "Licensing Basis for the Protected Service Water System - Responses to Request for Additional Information," dated July 11, 2012.

3. Letter from T. Preston Gillespie, Vice President, Oconee Nuclear Station, Duke Energy Carolinas, LLC, to the U.S. Nuclear Regulatory Commission, "Licensing Basis for the Protected Service Water System - Responses to Request for Additional Information - Supplement 1 " dated July 20, 2012.

4. Letter from T. Preston Gillespie, Vice President, Oconee Nuclear Station, Duke Energy Carolinas, LLC, to the U.S. Nuclear Regulatory Commission, "Licensing Basis for the Protected Service Water System - Responses to Request for Additional Information - Supplement 2," dated August 31, 2012.

5. Letter from T. Preston Gillespie, Vice President, Oconee Nuclear Station, Duke Energy Carolinas, LLC, to the U.S. Nuclear Regulatory Commission, "Licensing Basis for the Protected Service Water System - Due Date Extension Notification for Responses to Request for Additional Information," dated August 15, 2012.

6. Email from John Boska, U.S. NRC, to Stephen Newman and Timothy D. Brown, Duke Energy Carolinas, LLC, dated September 17, 2012.

www. duke-energy.corn

U. S. Nuclear Regulatory Commission November 2, 2012 Page 2 By letter dated June 11, 2012, Duke Energy Carolinas, LLC (Duke Energy) formally received a Nuclear Regulatory Commission (NRC) Request for Additional Information (RAI) (Reference 1) associated with the design and licensing bases for the proposed Protected Service Water (PSW) system. Duke Energy responded to the RAI items by letters dated July 11, 2012, July 20, 2012, and August 31, 2012 (References 2, 3, and 4).

On September 17, 2012, Duke Energy received five (5) additional follow-up RAI items (Reference 6). These RAIs have been sequentially numbered #163 to #167. This submittal contains Duke Energy's responses to these most recent RAI items in addition to the final response to RAI item #141, which supersedes the previous response dated July 20, 2012, (Reference 3).

If you have any questions in regard to this letter, please contact Stephen C. Newman, Regulatory Affairs Senior Engineer, Oconee Nuclear Station, at (864) 873-4388.

I declare under penalty of perjury that the foregoing is true and correct. Executed on November 2, 2012.

Sincerely, T. Preston Gillespie, Jr.

Vice President Oconee Nuclear Station Enclosure - Responses to Request for Additional Information - Supplement 3

U. S. Nuclear Regulatory Commission November 2, 2012 Page 3 cc: (w/enclosure)

Mr. John P. Boska, Project Manager (by electronic mail only)

U. S. Nuclear Regulatory Commission Office of Nuclear Reactor Regulation 11555 Rockville Pike Rockville, MD 20852 Mr. Victor M. McCree, Administrator, Region II U.S. Nuclear Regulatory Commission Marquis One Tower 245 Peachtree Center Ave., NE, Suite 1200 Atlanta, GA 30303-1257 NRC Senior Resident Inspector Oconee Nuclear Station Ms. Susan E. Jenkins, Manager Radioactive & Infectious Waste Management SC Dept. of Health and Environmental Control 2600 Bull St.

Columbia, SC 29201

Enclosure Responses to Request for Additional Information - Supplement 3

Enclosure - Responses to Request for Additional Information - Supplement 3 November 2, 2012 Page 2 RAI #163:

In its letters dated December 16, 2011, January 20, 2012, and July 11, 2012, the licensee proposed SR 3.7.1Oa.2 to verify battery pilot cell voltage ->2.07 V for the proposed PSW System battery. The staff's review of Oconee TS SR 3.8.5 Table 3.8.5-1 Battery Cell Surveillance Requirements for the station batteries indicated battery pilot cell float voltage limit is 2t 2.13 V.

Provide justification for deviation on pilot cell float voltage limit in the proposed LAR TS SR 3.7.1Oa.2 from existing TS Table 3.8.5-1.

Duke Energy Response:

Since Protected Service Water (PSW) is a new system, Duke Energy used the Babcock and Wilcox Plant Standard Technical Specifications (Revision 3) for the proposed PSW Technical Specifications and Bases and in particular, for the battery cell parameters found in PSW SR 3.7.1Oa.2.

Existing Oconee TS Table 3.8.5-1 have Category A, B and C limits with Category A and B float voltage limits of > 2.13 V for pilot and connected cells respectively and a Category C connected cell float voltage limit of > 2.07 V.

This differs from the proposed PSW TS SR 3.7.10a.2 of > 2.07 V which does not have an equivalent Table with Category A, B and C battery cell parameter limits in the Standard Technical Specifications. The reason for this difference is that all other Oconee non-PSW DC systems are constructed and formatted per the Improved Technical Specifications (ITS).

Use of the > 2.07 V as an acceptable minimum value was previously justified in RAI response 114 contained in Duke Energy letter dated July 11, 2012.

RAI #164:

In its letter dated December 16, 2011, the licensee states, "Additional preventive maintenance, testing, and monitoring performed in accordance with the PSW Battery Monitoring and Maintenance Program is conducted as specified in Specification 5.5.xx."

However, the staff's review of the LAR did not find PSW Battery Monitoring and Maintenance Program specified in Specification 5.5.xx. Provide a copy or mark up of PSW Battery Monitoring and Maintenance Program in Specification 5.5.xx for staff's review.

Duke Energy Response:

A new TS 5.5.22, "Battery Monitoring and Maintenance Program," was added and instances of 5.5.xx were changed to 5.5.22. A revised TS package will be submitted as part of the supplemental response to RAI 107 that includes TS 5.5.22 as follows:

Enclosure - Responses to Request for Additional Information - Supplement 3 November 2, 2012 Page 3 5.5.22 Battery Monitoring and Maintenance Program This program is applicable only to the Protected Service Water Batteries and provides for battery restorationand maintenance, based on the recommendation of IEEE Standard 450-1995. "IEEERecommended Practicefor Maintenance, Testing, and Replacement of Vented Lead-Acid Batteries for StationaryApplications," including the following:

a. Actions to restore ProtectedService Water battery cells with float voltage <2.0 V, and

b. Actions to restore ProtectedService Water battery cells with electrolyte level below the minimum or above the maximum indicationlevel mark.

The revised PSW TS and Bases are scheduled to be provided to the Staff by January 31, 2013.

RAI #165:

In its responses dated January 20 and July 11, 2012, to the Staff's RAls 62 and 134

[EEEB25] respectively related to the Environmental Qualification (EQ) of the PSW equipment, the licensee stated that a new 5.0 kilo Volt (kV) Manual Disconnect Switches and 5.0 kV Motor Operated Disconnect Switches were added to the EQ program and these switches were qualified in accordance with IEEE Std. 323-1983. The switches were added due to a radiation requirement total integrated dose (TID) utilizing a 40.0 year normal dose plus one year accident (design basis event) dose of 1.6E3 RADs. However, the licensee did not address EQ of the cables, cable connections and other components that will be connected to these two new switches located in the same EQ zone for a radiation TID dose requirement. Provide a summary table showing all PSW electrical equipment in the EQ zone (where these two new switches will be installed) including cables, cable connections, their safety qualification (i.e., safety-related or non- safety-related), IEEE Std. and versions used for EQ, environmental conditions they have been qualified for (temperature, radiation, pressure, humidity etc.).

Duke Energy Response:

Table 165-1 (shown below) lists the PSW equipment/components in the same Environmental Qualification (EQ) Zone as the new 5.0 kilo Volt (kV) manual alignment switches (1/2/3HPISXALGN001) and 5.0kV motor operated transfer switches (1/2/3HPISXTRN001 &

002). Medium voltage cables are used for power feeds to and from the manual alignment switches and the motor operated transfer switches. The medium voltage connections to the various switches are made with Burndy Un-Insulated lugs and 3M stress cones. The motor operated transfer switches utilize 125 VDC as the incoming control voltage and then converts the 125 VDC to 24 VDC for actual control component usage. The low voltage control cables (125 VDC and below in this application) connect the control power and/or indication/control circuits to and from the manual alignment switches and the motor operated transfer switches, utilizing Thomas & Betts (T&B) Tefzel insulated connectors.

The normal High Pressure Injection (HPI) pump power is routed through the 5kV motor operated transfer switches and aligned to the normal power supply. These switches are not required to change position during a Loss of Coolant Accident (LOCA), but are required to remain functional in a LOCA environment; therefore, the motor operated transfer switches are included in the EQ program.

Enclosure - Responses to Request for Additional Information - Supplement 3 November 2, 2012 Page 4 The manual alignment switch is used to select which HPI pump is powered from PSW. Normal power is not routed through this switch; however, this switch interfaces with the motor operated transfer switches. To insure a LOCA environment induced failure of the manual alignment switch doesn't adversely impact the motor operated transfer switches, the manual alignment switch is included in the EQ program.

The 125 VDC Power Panel (1/2/3PSWPL2DC) that provides control power to the 5kV motor operated transfer switches is located in the same EQ Zone as the transfer switches but are not in the EQ Program because the panel supply (125 VDC) to the motor operated transfer switches is not required to be available during the LOCA event since the transfer switch is not required to change position during the LOCA event.

The 5kV motor operated transfer switches and the 5kV manual alignment switches are included in Environmental Qualification Maintenance Manual (EQMM) Sections EQMM-1393.01-N1O-01 and EQMM-1393.01-NlO-00, respectively. The commodities component type! parts (i.e. cables, connectors, stress cones, etc.) are covered by Duke Energy EQ Document number EQMM-1393,01-M01-00, which covers Commercial Grade/Approved Vendor Items.

Enclosure - Responses to Request for Additional Information - Supplement 3 November 2, 2012 Page 12 RAI #166:

In its response dated July 20, 2012, to the staff RAI 160 [EMCB 15], the licensee states, "For the PSW project, QA-1 electrical equipment was seismically qualified in accordance with IEEE Std. 344 -1975..." However, in its letter dated January 20, 2012, to the staffs RAI 62, the licensee did not include IEEE Std. 344-1975, "Seismic Qualification of Class 1E Equipment for Nuclear Power Generating Stations" in Table of Industry Standards and Codes for 13.8 kV Switchgears (Keowee). Clarify that the new 13.8 kV Switchgears (Keowee) for PSW system are seismically qualified in accordance with IEEE Std. 344-1975 and the licensee's response dated July 20, 2012 includes evaluation of seismic qualification of the new 13.8 kV Switchgears (Keowee).

Duke Eneray Response:

The 13.8 kV Switchgear located at Keowee for the PSW system was seismically qualified in accordance with IEEE 344-1975. This was documented as a requirement within the procurement specification for the equipment as Reference 1.5.1.17 in Duke Energy Specification KS-0303.00-00-0002, "Procurement Specification for the Design, Fabrication and Testing of QA-1, Keowee Hydro Station, 13.8 KV Medium Voltage (KPF) Switchgear, Protective Relay Electrical Board (EB20) and Non-QA-1 Electrical Support Equipment for the Protected Service Water (PSW) System," Rev. 5. The qualification of the equipment outlined in that procurement specification was documented in Duke Energy Vendor Manual KM 303.--0037.001, "Qualification Report for Cutler Hammer 15KV Switchgear," Rev 2.

Qualification of electrical equipment was discussed in Duke Energy's response to RAI-160 dated July 20, 2012. The response was written in generic terms to address the methodology for seismic qualification of PSW electrical equipment. Included in that write-up were two examples of electrical equipment qualifications with the applicable references to procurement specifications, qualification plans, qualification reports and final Duke Energy Vendor manuals documenting the completed seismic qualification. Due to the extensive list of equipment qualified for the PSW system, not all of the electrical equipment and corresponding qualification documentation was referenced or discussed in the RAI-160 response. However, QA Condition 1 electrical equipment related to the PSW system was qualified using the methodology outlined in RAI-160 and in accordance with IEEE 344-1975. The specific references for the Keowee 13.8 kV switchgear are as shown above.

RAI #167:

In its letter dated December 16, 2011, to the staffs RAI 66, the licensee states, 'With the 13.8 kV overhead feeding the PSW electrical system, the minimum battery charger voltage is 501 V alternating current (AC) that occurs approximately 5 seconds after motor starting.

In approximately 13 seconds, battery charger input voltage has recovered to 576 V AC which is within the battery charger input voltage range.....; During a brief interruption of battery charger operation during motor starting for either the Keowee or 13.8 kV overhead power sources, the PSW DC system will be capable of performing it design function since the battery will maintain the required system voltage until battery charger input voltage recovers." Provide the following:

1. Provide a technical basis (industry standard or Code) to justify acceptability of design of new safety-related battery chargers where a design allows an interruption of

Enclosure - Responses to Request for Additional Information - Supplement 3 November 2, 2012 Page 13 battery charger operation due to analyzed lower input supply voltage to the battery charger.

2. Confirm that above lower voltage condition during motor starting will not result in tripping, malfunction, or spurious actuation of any PSW equipment including dropping of contactors, opening fuses, actuation of relays etc...

Duke Energy Response:

During normal operation, the PSW QA-1 battery and its respective QA-1 charger are both connected to the PSW DC distribution bus and operate as parallel sources to supply the connected loads while maintaining the battery in a fully charged state.

Upon voltage degradation or complete loss of the PSW charger AC input power supply causing the charger to cease operation, the PSW battery will perform its Design Basis function by providing DC power to components associated with the PSW system for four (4) hours.

This mode of operation is described generally in IEEE Standard 946-2004 (IEEE Recommended Practice for the Design of DC Auxiliary Power Systems for Generating Stations) and in particular, Section 4.1 of the Standard.

During the brief period when the AC input voltage for the PSW battery charger is below the minimum value, the PSW battery will maintain the required PSW DC bus voltage and there will be no loss, malfunction, protective device actuation or spurious actuation of any PSW DC equipment.

As described in the response to RAI 66 in Duke Energy letter dated December 16, 2011, the chargers will automatically resume operation upon recovery of charger AC input voltage to the minimum value.

RAI #141:

According to the licensee's letter dated March 16, 2012, the ONS UFSAR mark-up included Section 9.7.1.2.5.1 which states the following:

"The design response spectra for the new structures correspond to the expected maximum bedrock acceleration of 0.1g (MHE). The design response spectra were developed in accordance with Regulatory Guide 1.122 (Reference 15). The dynamic analysis is made using the STAAD-PRO computer program. The structure is built on structural fill. A ground motion time history was developed based on the soil properties and amplified response spectra generated at elevations of significant nodal mass."

Provide the following:

a) Considering that the PSW building is described as founded on the structural fill, provide a detailed description of rock motion, anchoring point for the input motion, and material properties of soil profile(s) overlaying bedrock (thickness, shear wave velocity, and other relevant material properties.) Also, discuss the response amplification calculation process that was used to determine the free-field horizontal and vertical ground motion at the PSW building.

b) Provide a detailed description of the procedures used for the seismic analysis of the PSW building and to develop the in-structure response spectra (floor design response

Enclosure - Responses to Request for Additional Information - Supplement 3 November 2, 2012 Page 14 spectra). If different from the methods and acceptance criteria outlined in the NRC standard review plan (SRP) 3.7.1 and 3.7.2, identify those differences and provide justification that the PSW building is adequately designed, using these alternative methods, to withstand the effects of earthquake loads.

c) Confirm and provide further information that STAAD-PRO and all features of this software related to the dynamic response analysis and static analysis have been verified and validated by its provider in compliance with 10 CFR Part 50, Appendix 8 and 10 CFR Part 21. Also, provide documentation which demonstrates that the software provider has been audited and approved as an Appendix 8 supplier.

d) Describe the method of combination of modal responses and spatial components used in the PSW building seismic response analysis. If different from the methods outlined in the NRC Regulatory Guide (RG) 1.92, identify those differences and discuss how these alternative methods provide assurance that the PSW building is adequately designed to withstand the effects of earthquake loads.

Duke Eneray Response:

This revised response supersedes in its entirety the response to NRC RAI 141 [EMCB6]

submitted via Duke Energy Letter dated July 20, 2012.

Seismic analyses supporting this RAI response comply with guidance provided in Standard Review Plan (SRP) 3.7.1, "Seismic Design Parameters," and 3.7.2, "Seismic System Analysis," except as noted in paragraphs b) and d) below.

a) Input Design Response Spectra and Time Histories The Protected Service Water (PSW) building is founded on overburden. For the PSW building design, the Maximum Hypothetical Earthquake (MHE) response spectra presented in the Updated Final Safety Analysis Report (UFSAR) Figure 2-55 was used, consistent with the Oconee Nuclear Station (ONS) licensing basis (UFSAR Section 3.7.1.1 "Design Response Spectra"). For the PSW Building MHE In-structure response spectra (ISRS) generation, the time history record of the North-South (N-S), May 1940 El Centro earthquake normalized to a peak acceleration of 0.1 5g was used as the input ground motion for both the vertical and horizontal excitation consistent with the ONS licensing basis (UFSAR Section 3.7.1.2 "Design Time History"). The Design Basis Earthquake (DBE) ground response spectra and ground motion time history peak ground acceleration (PGA) are 50% of the MHE response spectra and ground motion time history PGA. The ONS MHE is equivalent to the Safe Shutdown Earthquake (SSE) and DBE is equivalent to the Operating Basis Earthquake (OBE) in today's terminology.

The use of 0.1 5g PGA response spectra presented in the UFSAR Figure 2-55 for the PSW building is consistent with that used for the design of the CT4 Block House, the only other Class 1 ONS structure founded on overburden.

Structural fill constitutes the upper 23 feet of the soil profile below the PSW building.

Beneath the fill, the soil profile gradually transitions into rock. Bedrock was established at a depth of 80 feet below the existing ground surface. The low strain (104 percent) soil properties and the soil/rock profile used in the site response analysis (deconvolution of the ground surface motions using SHAKE) are shown in Table 141-1. The Poisson's ratio and the best estimate (BE) shear wave velocity (Vs) in Table 141-1 were obtained from Cone Penetration Test (CPT) and Cross-Hole Tests. The lower bound (LB) and upper bound (UB) shear wave velocities were calculated from the LB and UB shear

Enclosure - Responses to Request for Additional Information - Supplement 3 November 2, 2012 Page 15 modulus (G) by dividing and multiplying the BE shear modulus by 1.5 in accordance with SRP 3.7.2 guidance.

The 0.15g MHE ground motion was deconvolved to the top of rock using SHAKE and using soil properties in Tables 141-1 and strain dependent modulus reduction and damping coefficients from Idriss (1990). As shown in Figure 141-1, the LB, BE,' and UB deconvolved top of rock outcrop response spectra has sufficient energy in the frequency range of interest (>3.0 Hz.) when compared to the MHE 0.1g PGA response spectra specified for structures founded on rock (UFSAR Section 3.7.1.1). The strain compatible (iterated) soil properties obtained from the SHAKE deconvolution analysis are shown in Tables 141-2, 141-3, and 141-4 for the LB, BE, and UB soil properties respectively.

The use of the 0.1 5g MHE ground motions in the ONS UFSAR for the PSW Building response analysis is at variance with that described in the July 20, 2012, RAI 141 response. The July 20, 2012, response to RAI 141 described the development of the MHE surface horizontal response spectra through a one dimensional (1-D) soil column (SHAKE) convolution analysis. The vertical surface response spectrum was scaled from the horizontal surface response spectra. For the MHE convolution analysis, the recorded N-S, May 1940 El Centro earthquake time history normalized to 0.1g was used as rock outcrop motion at 80 ft. below the ground surface. The developed MHE surface response spectra shape is not appropriate for the PSW site because the N-S, May 1940 El Centro earthquake motion is a surface motion recorded at a firm soil site (United States Geological Survey (USGS) Site Classification C 180-360 meters/second [590-1180 feet/second] Shear wave velocity). The top of rock under the PSW building is 80 ft.

below the ground surface. Use of the N-S, May 1940 El Centro earthquake time history as the MHE rock outcrop motion to develop the MHE surface motion is not appropriate because it has effectively amplified the soil motions twice - once in the original El Centro recorded time history and second in the 1-D soil column convolution (SHAKE) analysis performed to develop the horizontal and vertical MHE ground design response spectra.

b) Seismic Design Procedures for PSW Building Design and ISRS Generation The PSW Building was conservatively designed to ensure that any variance between the "as designed" and the "as built" configurations could be accommodated. Re-analysis of the PSW building has been performed using the "as built" configuration. For the re-analysis, the response spectra method of analysis was used to determine the maximum design forces of various structural components of the PSW building and the maximum foundation soil bearing pressures. For ISRS generation, the time history method of analysis was used to develop absolute acceleration time histories at the various nodes where equipment is located. The ground motion inputs for the response spectra and the time history response analyses were described in paragraph a) above. For both the building design and ISRS generation, the model and analysis parameters were as follows:

i) The PSW building consists of concrete and steel framing floors, a concrete roof, concrete shear walls, and concrete foundations. The structure was analyzed using a three dimensional (3-D) Finite Element (FE) model representing the superstructure and the foundations. The concrete elements were modeled using 4-noded thin plate (shell) elements with 6 degrees of freedom (DOF)/node. The steel elements were modeled using 2-node beam elements with 6 DOF/node. Figure 141-2 shows the FEM model used for the seismic analysis of the PSW building. In this figure, the building shell elements are shown in blue. The black circles are member end moment releases at the

Enclosure - Responses to Request for Additional Information - Supplement 3 November 2, 2012 Page 16 end of beam elements. The shell elements for the two entry ways and the Battery Room wall foundation are shown in red.

ii) The nodal mass included contributing mass from static loads on the structure.

For the mass calculations, 100% of the dead (permanent) loads (e.g., weight of structure and equipment) and 25% of the live (short term) load (e.g., general live load) was considered. The equipment mass was lumped at the location of the equipment. The mass of cable tray, HVAC ducts, and piping and their supports were modeled as distributed mass on floors and walls.

iii) The PSW building model described above was used for the seismic response analysis with two sets of boundary conditions to model the PSW building foundation. The first was a fixed base model where the foundation nodes were fixed consistent with the current seismic design basis (CDB) of other ONS Class 1 structures. The second was a confirmatory model that used Lumped Soil Springs (LSS) to model soil structure interaction (SSI) effects. The soil springs were modeled at the foundation/structure interface nodes.

For the CDB model, all the foundation nodes at elevation 789'-3" are fixed in all six degrees of freedom. For the entry ways and Battery Room wall foundation at elevation 797' (shown in red on Figure 141-2), springs to approximately model the elastic restraint provided to these small foundations by the soil under the foundations at elevation 797' were used. Vertical and horizontal soil spring constants were calculated using the ASCE 4-98 Section 3.3.4.2.2 formulation.

Fixed boundary condition for the battery room wall and entry way foundation was not used because if the entry way and Battery Room wall foundation nodes at elevation 797' are fixed, the response for the operating floor at elevation 797', where most of the equipment is located, will be unconservative (same as the input ground motion). In addition, the fixed boundary condition will force the majority of lateral load from the operating floor to be resisted by the fixed nodes of the small entry way foundation (approximately 9'xl 1'). This would not be representative of the "designed" load path where the majority of the operating floor inertia (seismic) loads will be transferred to the building foundation at elevation 789'-3" through supporting shear walls during a seismic event. Free boundary condition at the entry way and Battery Room wall foundation nodes at elevation 797' would result in the entry way structure and Battery Room wall inertia loads transferred to the PSW walls or the Battery Room roof respectively. This also is not representative of the "designed" load path where the inertia loads from the entry way and the Battery Room wall will be partially transferred to the respective foundations at elevation 797'.

For the LSS model, Tables 141-2, 141-3, and 141-4 soil profile and strain compatible soil properties were used to calculate the LB, BE, and UB LSS parameters for the PSW Building 'response analysis. The methodology detailed in Christiano (1974) was followed to compute the equivalent shear modulus for the soil profile layers under the PSW foundation. In this procedure, average shear modulus value is developed whereby each layer is weighted in accordance with the strain energy in that layer. This method quantifies the diminishing effect of the soil layers on the overall impedance of the foundation soil with increasing depths from the bottom of the foundation. The soil spring parameters (spring constant and damping) were computed based on the formulation in ASCE 4-98 Section 3.3.4.2.2 using the equivalent shear modulus

Enclosure - Responses to Request for Additional Information - Supplement 3 November 2, 2012 Page 17 for the layered soil profile. The PSW building foundation consists of interconnected multiple strip footings. The box shaped monolithic N-S and E-W shear walls supported on these strip footings provide the rigidity to the foundation for all the horizontal, vertical, rocking, and torsional degrees of freedom. The LSS vertical and horizontal springs and dampings were computed for the various strips of PSW building foundations. In the 3-D FEM model, these vertical and horizontal springs also provide the equivalent rocking and torsional lumped soil spring parameters consistent with the spatial distribution of the foundation strips.

iv) Consistent with ONS UFSAR Section 3.7.1.3, 2% damping for steel elements and 5% damping for reinforced concrete elements were used for MHE. The 2%

steel and 5% concrete MHE damping values are lower (conservative) when compared to the 4% steel and 7% concrete SSE dampings specified in Regulatory Guide 1.61. Composite modal damping (stiffness proportional) was used for both the CDB and LSS response analyses. However, for the LSS response analysis, if the calculated composite modal damping exceeded 20%

for any mode, the LSS soil spring damping was reduced so that composite modal dampings for all modes were less than or equal to .20%.

v) For the CDB time history response analysis for ISRS development, 100 modes (up to 42 Hz.) were considered. For the CDB response spectra analysis for shear force calculation 59 modes (up to, 24 Hz.) together with the effect of the missing mass was considered to account for 100% of the total system mass in the three orthogonal directions [X (N-S), Y (Vertical), and Z (E-W)]. The 24 Hz.

frequency corresponds to the rigid frequency of the input ground response spectra (UFSAR Figure 2-55). For the CDB response spectra analysis for moment calculations a large number of modes (771 modes) accounting for 96% of the X-directional mass, 90% of the Y-directional mass, and 96% of the Z-directional mass were considered because STAAD-PRO software does not have the capability to account for the missing mass for moment calculations.

For the LSS response analysis (both response spectra and time history),

sufficient number of modes were considered (61 modes for LB, 76 modes for BE, and 107 modes for UB) to account for at least 95% of the total system mass in each of the three orthogonal directions [X (N-S), Y (Vertical), and Z (E-W)].

vi) The PSW building seismic forces and moments from the CDB and the LSS analyses are bounded by the conservative seismic forces and moments considered in the original PSW building design. Thus, the PSW building design is adequate for the CDB and LSS design responses. Similarly, the CDB and the LSS seismic foundation bearing pressures are lower than in the seismic bearing pressures considered in the original design and do not produce foundation uplift.

vii) Accidental torsion (an eccentricity of +/-5% of the maximum building dimension per SRP 3.7.2) was not considered in the PSW building design. However, the PSW finite element model used for CDB and LSS response calculations accurately models the inherent eccentricity of the PSW structure layout. Also, all significant equipment loads were modeled at their physical locations within the building. In addition, the PSW building's box shaped shear wall arrangement with concrete floors (diaphragms) provides a structural system

Enclosure - Responses to Request for Additional Information - Supplement 3 November 2, 2012 Page 18 that has a large capacity to resist torsion. Thus, consideration of the accidental torsion was not necessary.

viii) The ISRS generation complies with RG 1.122 guidance relative to the frequency intervals for ISRS generation and ISRS peak widening. ISRS were widened +/-15% on the frequency scale. The frequencies for ISRS generation included structural modal frequencies in addition to frequencies based on Table 1 of RG 1.122. However, periods (1/frequency) closer than 0.0007 seconds were eliminated from the combined RG 1.122 and structural frequencies list.

This elimination of extremely close periods has practically no effect on the widened (+/-15%) ISRS used for equipment qualification. ISRS were developed for all applicable damping values for equipment and support qualifications as specified in UFSAR Section 3.7.1.3.

The DBE ISRS are one-half (1/2) of the corresponding MHE ISRS. This is justified because the percent of critical damping for steel and concrete' structural elements are the same for MHE and DBE (UFSAR section 3.7.1.3) and the' design ground motion for DBE is one-half of the MHE ground motion (UFSAR sections 3.7.1.1 and 3.7.1.2).

ix) The equipment and components inside the PSW building will be conservatively evaluated to the seismic loadings resulting from both the CDB and the LSS model ISRS. Previous responses to NRC RAIs 160, 161, and 162 will be evaluated and revised, if required.

c) Duke Energy contracted S&L to perform the PSW Building seismic response analysis and ISRS development as a safety related scope to be performed under the S&L QA Program. The S&L QA program complies with 10 CFR Part 50 Appendix B and 10 CFR Part 21 requirements and has been approved by the NRC (Accession No. ML090750737, ML090750638, and ML12142A195). The S&L QA program is audited by the Nuclear Procurement Issues Committee (NUPIC) as a matter of course. Duke Energy subscribes to NUPIC audits. The S&L QA Program and Standard Operating Procedure (SOP)-204 implementation has also been audited by the NRC on past S&L projects (example: South Texas Project, Units 3 and 4 Combined Operating License Application, Docket Number 52-12 and 52-13).

The STAAD-PRO software has been validated in accordance with Sargent & Lundy SOP-0204. SOP-0204 governs all software validation and verification (V&V) at S&L and is the implementing procedure for the S&L NQA-1 1994 compliant Nuclear QA Program.

S&L has validated (V&V) STAAD-PRO for development of the ISRS using the time history method of analysis. S&L has also validated (V&V) the STAAD-PRO response spectra method of analysis when modal response combinations are performed using the complete quadratic combination (CQC) method.

The STAAD-PRO software was used for the PSW building finite element modeling and seismic analyses. The PSW ISRS were developed using the time history method of analysis. The PSW building element design forces were developed using the response spectra method of analysis. The CQC method was used to'combine modal responses' when the response spectra method was used.

d) For the response spectra method of analysis (used for the PSW Building response analysis), the responses were calculated for the X-, Y-, and Z-excitations individually.

The modal responses for these individual analyses were combined using the complete

Enclosure - Responses to Request for Additional Information - Supplement 3 November 2, 2012 Page 19 quadratic combination (CQC) method in accordance with Regulatory Guide (RG) 1.92, section C.1.1.

For the time history analysis (used for developing the PSW Building ISRS), the response was'calculated for the X-, Y-, and Z-excitations individually. The modal responses for these individual time history analyses were combined algebraically at each time step.

The co-directional responses (maximum element forces and ISRS at selected nodes) from the individual X-, Y-, and Z-direction excitation analysis (using the response spectra method or the time history method) were summed using absolute sum rule to obtain the summed X-component, Y-component, and Z-component of the design responses (maximum element forces and ISRS at selected nodes) as follows:

Rx = (Rxx + Rxy + Rxz)

Ry = (Ryx + Ryy + Ryz)

Rz = (Rzx + Rzy + Rzz)

Where:

Rx = summed X-component of the design response (maximum element force or unwidened ISRS at the selected node)

Ry = summed Y-component of the design response (maximum element force or unwidened ISRS at the selected node)

Rz = summed Z-component the design response (maximum element force or unwidened ISRS at the selected node)

Rxx = X-component of design response (maximum element force or unwidened ISRS at the selected node) due to X-excitation Rxy = X-component of the design response (maximum element force or unwidened ISRS at the selected node) due to Y-excitation Rxz = X-component of the design response (maximum element force or unwidened ISRS at the selected node) due to Z-excitation Ryx = Y-component of the design response (maximum element force or unwidened ISRS at the selected node) due to X-excitation Ryy = Y-component of the design response (maximum element force or unwidened ISRS at the selected node) due to Y-excitation Ryz = Y-component of the design response (maximum element force or unwidened ISRS at the selected node) due to Z-excitation Rzx = Z-component of the design response (maximum element force or unwidened ISRS at the selected node) due to X-excitation Rzy = Z-component of the design response (maximum element force or unwidened ISRS at the selected node) due to Y-excitation Rzz = Z-component of the design response (maximum element force or unwidened ISRS at the selected node) due to Z-excitation ONS is a two-directional earthquake motion plant according to the UFSAR, Section 3.7.2.5. ONS structures, systems, and components (SSCs) were designed for the two-directional. earthquake with the exception of the SSCs for the Standby Shutdown Facility (SSF) where the three spatial components of the earthquakes were combined using the square root of the sum of the squares (SRSS) rule; therefore, the PSW SSCs are designed/qualified for the two-directional earthquake using the absolute sum combination, i.e., maximum of the absolute sum of (R, plus Ry) or (Rz plus Ry).

The two-directional earthquake and absolute sum rule is at variance with Standard Review Plan (SRP) 3.7.2 which combines the three spatial components of the

Enclosure - Responses to Request for Additional Information - Supplement 3 November 2, 2012 Page 20 earthquakes using the SRSS rule. However, the two-directional earthquake with the absolute sum rule yields design responses that are comparable to those obtained using the SRSS rule. For example, if a design response has the same response magnitude (say 1.0) from each of the'three spatial excitations (X, Y, and Z), the absolute sum rule will yield a combined design response of 2.0 compared to 1.73 for the combined design response using the SRSS rule.

Enclosure - Responses to Request for Additional Information - Supplement 3 November 2, 2012 Page 21 Table 141-1: PSW Soil Profile and Low Strain (10- percent) Soil Properties Layer Name Depth Elevation Unit Weight BE Vs Poisson's BE G LB Vs UB Vs (ft) (Jt) (pcf) (ROs) Ratio (ksf) (fps) (fps)

Fill 0-16 Surface- 121 897 0.30 3024 732 1099 779 16-23 779-772 122 897 0.30 3049 732 1099 Residual 23-43 772-752 125 1042 0.40 4215 851 1276 Soil 43-51 752-744 127 1042 0.40 4282 851 1276 Partially Weathered 51-65 744-730 135 1674 040 11749 1367 2050 Rock Weathered 65-75 730-720 160 2559 0.40 32539 2089 3134 Rock I Transitional 75-80 720-715 170 4659 0.40 114598 3804 5706 Rock Rock 80+ <715 170 6942 0.4 254426 566 8502 Legend:

BE = Best Estimate ft = feet ksf = kips per square foot LB = Lower Bound pcf = pounds per cubic foot Vs = Shear Wave Velocity UB = Upper Bound fps = feet per second G = Shear Modulus

Enclosure - Responses to Request for Additional Information - Supplement 3 November 2, 2012 Page 22 Table 141-2: Lower Bound Strain Compatible Soil Properties for Input Motion at Ground Surface with ZPA 0.15 g Layer Name Layer Depth Elevation Unit Poisson's Shear Shear Damping Thickness (ft) ") Ratio Modulus Wave Ratio (ft) (pci) (ksW) Veocit Fill Surface -

5,0 0-5 790 121 0.30 1971 724 0.01 5.0 5-10 790-785 121 030 1847 701 0018 6.0 10-16 785-779 121 0.30 1739 680 0.026 7.0 16 - 23 779-772 122 0.30 1604 651 0.033 Residual 6.0 23-29 772 - 766 125 040 2259 763 0032 Soil 6.0 29-35 766 - 760 125 0.40 2123 740 0.037 8.0 35-43 760-752 125 0.40 1990 716 0.041 8.0 43-51 752 - 744 127 040 1909 696 0.047 Partially 7.0 51-58 744 - 737 135 040 6830 1276 0.025 Weathered Rock 7.0 58-65 737-730 135 0-40 6742 1268 0.026 Weathered Rock 10.0 65-75 730-720 160 0.40 20646 2038 0.015 Transitional Rock 5.0 75-80 720-715 170 040 75648 3785 0.008 Legend.

ft = feet pcf = pounds per cubic foot fps = feet per second ksf = kips per square foot

Enclosure - Responses to Request for Additional Information - Supplement 3 November 2, 2012 Page 23 Table 141-3: Best Estimate Strain Compatible Soil Properties for Input Motion at Ground Surface with ZPA 0.16 g Laywr Layer Depth Elevation Unit Poisson's Shear Shear Oamping Nane Thickness (it) (it) Weight Ratio Modulus Wave Ratio (it) (pct) (s) Velocity Fill Surface -

5.0 0-5 790 121 0.30 2994 893 0-008 5.0 5-10 790-785 121 030 2897 878 0014 6.0 10-16 785-779 121 0.30 2733 853 0.019 7.0 16-23 779-772 122 0.30 2639 835 0.025 Residual 6.0 23 - 29 772 - 766 125 040 3670 972 0025 Soil 6.0 29-35 766-760 125 040 3585 961 0,028 8.0 35-43 760 - 752 125 0.40 3395 935 0.032 8.0 43-51 752-744 127 0-40 3280 912 0036 Partially 7.0 51-58 744-737 135 040 10630 1592 0019 Weathered Rock 7.0 58-65 737-730 135 0.40 10496 1582 0.021 Weathered Rock 10.0 65-75 730-720 160 0.40 31462 2516 0012 Transition al Rock 5.0 75-80 720-715 170 040 13798 4643 0007 Legend.

ft = feet pcf = pounds per cubic foot fps = feet per second ksf = kips per square foot

Enclosure - Responses to Request for Additional Information - Supplement 3 November 2, 2012 Page 24 Table 141-4: Upper Bound Strain Compatible Soil Properties for Input Motion at Ground Surface with ZPA 0.15 g Layer Layer Depth Elevation Unit Poisson' Shear Shear Dampin Name Thicknes (ft) (it) Weight s Rato Modulus Wave g Ratio s (ft) (pc) (ks") Velocity Fill Surface -

5.0 0-5 790 121 0.30 4510 1096 0.006 5.0 5-10 790-785 121 0.30 4406 1083 0.011 6.0 10-16 785-779 121 0.30 4287 1068 0.015 7.0 16-23 779-772 122 0.30 4146 1046 0.019 Residual 6.0 23-29 772-766 125 0.40 5760 1218 0.018 Soil 6.0 29-35 766-760 125 0.40 5627 1204 0022 8.0 35-43 760-752 125 0.40 5505 1191 0.025 8.0 43-51 752-744 127 0.40 5489 1180 0.027 Partially 7.0 51-58 744-737 135 0.40 16625 1991 0.015 Weathered Rock 7.0 58-65 737-730 135 0.40 16412 1979 0.016 Weathered Rock 10.0 65-75 730-720 160 0.40 47676 3098 0.01 Transition al Rock 5.0 75-80 720-715 170 0.40 171192 5694 0.005 Legend:

ft = feet pcf = pounds per cubic foot fps = feet per second ksf = kips per square foot

Enclosure - Responses to Request for Additional Information - Supplement 3 November 2, 2012 Page 25 FIGURE 141-1 Comparison for 5% Damping at Outcrop of Bedrock (80 ft Below Grade) 0.50 0.45 040 IU s RS (So*) at Bedrock.-1940 El  !

icentro N-S 0.159 at Ground Surface

• LB RS 4VO) at Bedrock - 1940 El i ]

035, ~~Centro N- S 0. 1 Sg at G ro und S usrface BE RS ( Beoat Bedrock - 94 1940 El 030 Cen5to N-S 0.15S at Ground 025 020 0 15 0,10 OCONEE UFSAR RS (5%) Figure 2-531 0 05 0-01 0.10 1.00 10.00 100.00 Frequency (Hz)

Enclosure - Responses to Request for Additional Information - Supplement 3 November 2, 2012 Page 26 FIGURE 141-2 PSW BUILDING FEM MODEL

[Mnwey Roomi foundation U1 PSW BUILDING ELEVATION Ir*Y Wauy Eiluy WaO IIH I BaIMr Room I oundatiloe PSW BtULDING PLAN A