RAIO-1017-56698, LLC Response to NRC Request for Additional Information No. 190 (Erai No. 9038) on the NuScale Design Certification Application
| ML17291B312 | |
| Person / Time | |
|---|---|
| Site: | NuScale |
| Issue date: | 10/18/2017 |
| From: | Rad Z NuScale |
| To: | Document Control Desk, Office of New Reactors |
| References | |
| RAIO-1017-56698 | |
| Download: ML17291B312 (24) | |
Text
RAIO-1017-56698 NuScale Power, LLC 1100 NE Circle Blvd., Suite 200 Corvalis, Oregon 97330, Office: 541.360.0500, Fax: 541.207.3928 www.nuscalepower.com October 18, 2017 Docket No.52-048 U.S. Nuclear Regulatory Commission ATTN: Document Control Desk One White Flint North 11555 Rockville Pike Rockville, MD 20852-2738
SUBJECT:
NuScale Power, LLC Response to NRC Request for Additional Information No.
190 (eRAI No. 9038) on the NuScale Design Certification Application
REFERENCE:
U.S. Nuclear Regulatory Commission, "Request for Additional Information No.
190 (eRAI No. 9038)," dated August 19, 2017 The purpose of this letter is to provide the NuScale Power, LLC (NuScale) response to the referenced NRC Request for Additional Information (RAI).
The Enclosure to this letter contains NuScale's response to the following RAI Questions from NRC eRAI No. 9038:
08.03.02-2 08.03.02-3 08.03.02-4 08.03.02-5 08.03.02-6 08.03.02-7 This letter and the enclosed response make no new regulatory commitments and no revisions to any existing regulatory commitments.
If you have any questions on this response, please contact Darrell Gardner at 980-349-4829 or at dgardner@nuscalepower.com.
Sincerely, Zackary W. Rad Director, Regulatory Affairs NuScale Power, LLC Zackary W. Rad Director Regulatory Affairs
RAIO-1017-56698 NuScale Power, LLC 1100 NE Circle Blvd., Suite 200 Corvalis, Oregon 97330, Office: 541.360.0500, Fax: 541.207.3928 www.nuscalepower.com Distribution:
Gregory Cranston, NRC, OWFN-8G9A Omid Tabatabai, NRC, OWFN-8G9A Samuel Lee, NRC, OWFN-8G9A : NuScale Response to NRC Request for Additional Information eRAI No. 9038
RAIO-1017-56698 NuScale Power, LLC 1100 NE Circle Blvd., Suite 200 Corvalis, Oregon 97330, Office: 541.360.0500, Fax: 541.207.3928 www.nuscalepower.com :
NuScale Response to NRC Request for Additional Information eRAI No. 9038
NuScale Nonproprietary Response to Request for Additional Information Docket No.52-048 eRAI No.: 9038 Date of RAI Issue: 08/19/2017 NRC Question No.: 08.03.02-2 FSAR Tier 2 states in Section 8.3.2.1.1, Highly Reliable Direct Current Power System, that the EDSS-C serves plant common loads summarized in Table 8.3-4, Highly Reliable Direct Current Power System - Common Nominal Loads.
The EDSS-C serves plant common loads which are summarized in FSAR Tier 2 Table 8.3-4.
QUESTION: A footnote to FSAR Table 8.3-4 states: Charger-only loads are de-energized by MPS/PPS at the onset of the battery duty cycle. Please clarify what is meant by charger-only loads."
NuScale Response:
NuScale has reclassified the "charger only" loads of FSAR Table 8.3-4 as momentary loads consistent with Section 4.2 of IEEE Std. 485-1997 (FSAR Reference 8.3-12) and has revised the table to reflect this change.
The revision to FSAR Table 8.3-4 indicates that certain EDSS-C loads are classified as momentary loads. These loads are de-energized by the plant protection system (PPS) upon detection of a loss of AC power to the EDSS-C chargers. The PPS logic that initiates this action is shown in FSAR Figures 7.1-3b and 7.1-3c. The figures show that there are no discrete time delays in the actuation circuits that de-energize the EDSS-C loads. Consistent with Section 4.2.3 of IEEE Std. 485-1997, the momentary EDSS-C loads are conservatively assumed to last for a full minute during the battery duty cycle.
The small increase in battery loading due to the additional minute to accommodate momentary loads has no significant impact on the battery capacity margin. The EDSS-C battery sizing calculations conservatively incorporate a design margin factor of 1.50. This design margin is intended to encompass potential load additions during NuScale plant design development (25%) and future load growth during plant operating life (25%).
NuScale Nonproprietary In addition to the load classification changes, a note has been added to FSAR Table 8.3-4 to clarify the basis for the load values.
Impact on DCA:
FSAR Table 8.3-4 and FSAR Section 8.3.2.2.1 have been revised as described in the response above and as shown in the markup provided in this response.
NuScale Final Safety Analysis Report Onsite Power Systems Tier 2 8.3-30 Draft Revision 1 the standard commercially available equipment ratings. See Table 8.3-8 for the EDNS regulating transformer sizing per subsystem.
8.3.2.2 Design Evaluation 8.3.2.2.1 System Interfaces Highly Reliable DC Power System The ELVS provides AC power to the EDSS battery chargers. AC power to the ELVS is provided by the normal AC power sources (main generators, onsite AC distribution, or offsite transmission grid, if supplied) or by the BDGs.
The EDSS-C and EDSS-MS loads are listed in Table 8.3-4 and Table 8.3-5.
Additionally, the following systems receive highly reliable DC power from the EDSS:
RAI 08.03.02-3 Module Protection System - EDSS-MS channels A, B, C, and D provide electrical power to MPS separation groups A, B, C, and D equipment, respectively. The EDSS-MS Division I (channels A and C) and Division II (channels B and D) provide electrical power to Division I and Division II MPS equipment, respectively. When AC input power to EDSS-MS battery chargers is unavailable, the MPS loads are energized for 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> and PAM loads are energized for 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br /> as described in Section 7.0.4.1.4.
In addition to energizing required loads during the EDSS battery duty cycle, the MPS de-energizes unneeded loads. The MPS logic that de-energizes loads in the event of a loss of AC power to the EDSS-MS battery chargers is shown in Figure 7.1-1ah.
RAI 08.03.02-2 Plant Protection System (PPS) - The EDSS-C Division I and Division II provide electrical power to PPS Division I and Division II equipment, respectively. When AC input power to the EDSS-C battery chargers is unavailable, the PPS loads required to support PAM are energized for 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br /> by the EDSS-C batteries. In addition to energizing required loads during the EDSS battery duty cycle, the PPS de-energizes unneeded loads. The PPS logic that de-energizes loads in the event of a loss of AC power to the EDSS-C battery chargers is shown in Figures 7.1-3b and 7.1-3c.
Plant Lighting System - The EDSS-C provides electrical power to MCR emergency lighting. The battery chargers are sized to accommodate this load during normal operation and the batteries are sized to provide power for a minimum of 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br /> following a loss of normal AC power.
Safety Display and Indication System (SDIS) - The EDSS-C provides electrical power to NPM-specific and common-plant safety displays. The battery chargers are sized to accommodate the display loads during normal operation and the batteries are sized to provide power to these loads for a minimum of 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br /> following a loss of normal AC power.
NuScale Final Safety Analysis Report Onsite Power Systems Tier 2 8.3-47 Draft Revision 1 RAI 08.03.02-2 Table 8.3-4: Highly Reliable Direct Current Power System - Common Nominal Loads Load Description (Div I)
- Load on Charger
- only (W / amps)
Load on Battery (W / amps)
Time Period (hours)
Load Classification Amp - hour CRVS control room envelope isolation damper #1 179.00 / 1.43 Charger-only**
CRVS control room envelope isolation damper #2 179.00 / 1.43 Charger-only**
CRVS control room envelope isolation damper #3 179.00 / 1.43 Charger-only**
CRVS control room envelope isolation damper #4 179.00 / 1.43 Charger-only**
Control room habitability system main air delivery valve 40.00 / 0.32 Charger-only**
Control room habitability system pressure relief valve 40.00 / 0.32 Charger-only**
CRVS air duct radiation monitor 75.00 / 0.60 0-72 Continuous 43.20 PPS cabinet 158.82 / 1.27 0-72 Continuous 91.44 PPS sensor input power 18.07 / 0.14 0-72 Continuous 10.08 SDIS cabinet 35.29 / 0.28 0-72 Continuous 20.16 SDIS main control room displays (module) 762.35 / 6.10 0-72 Continuous 439.20 SDIS main control room displays (common) 63.53 / 0.51 0-72 Continuous 36.72 RMS reactor pool area radiation monitor #1 35.00 / 0.28 0-72 Continuous 20.16 RMS reactor pool area radiation monitor #2 35.00 / 0.28 0-72 Continuous 20.16 PLS main control room emergency lighting 440.00 / 3.52 0-72 Continuous 253.44 EDSS battery monitor 50.00 / 0.40 0-72 Continuous 28.80 Total continuous battery load 1673.06 / 13.38 Total charger - only load 796.00 / 6.36 Actual amp - hours removed 963.36
- Also applicable to Div II
- Charger-only loads are de-energized by MPS/PPS at the onset of the battery duty cycle.
NuScale Final Safety Analysis Report Onsite Power Systems Tier 2 8.3-48 Draft Revision 1 RAI 08.03.02-2 Table 8.3-4: Highly Reliable Direct Current Power System - Common Nominal Loads1 Load Description (Division I)2 Battery Load (W, amps)
Time Period Load Classification3 Amp-hour CRVS Control Room Envelope Isolation Damper #1 179.00 1.43 60 sec Momentary 0.02 CRVS Control Room Envelope Isolation Damper #2 179.00 1.43 60 sec Momentary 0.02 CRVS Control Room Envelope Isolation Damper #3 179.00 1.43 60 sec Momentary 0.02 CRVS Control Room Envelope Isolation Damper #4 179.00 1.43 60 sec Momentary 0.02 CRHS Main Air Delivery Valve 40.00 0.32 60 sec Momentary 0.01 CRHS Pressure Relief Valve 40.00 0.32 60 sec Momentary 0.01 CRVS Air Duct Radiation Monitor 75.00 0.60 72 hr Continuous 43.20 PPS Cabinet 158.82 1.27 72 hr Continuous 91.44 PPS Sensor Input Power 18.07 0.14 72 hr Continuous 10.08 SDIS Cabinet 35.29 0.28 72 hr Continuous 20.16 SDI Main Control Room Displays (module) 762.35 6.10 72 hr Continuous 439.20 SDI Main Control Room Displays (common) 63.53 0.51 72 hr Continuous 36.72 RMS Reactor Pool Area Radiation Monitor #1 35.00 0.28 72 hr Continuous 20.16 RMS Reactor Pool Area Radiation Monitor #2 35.00 0.28 72 hr Continuous 20.16 PLS Main Control Room Emergency Lighting 440.00 3.52 72 hr Continuous 253.44 EDSS battery monitor 50.00 0.40 72 hr Continuous 28.80 Total Continuous Load (ILC) 1673.06 13.38 Total Noncontinuous Load (ILN) 0.00 0.00 Total Momentary Load (ILM) 796.00 6.36 Actual Amp-Hours Removed (Q) 963.46 1 The loads assumed for each divisional battery are estimated nominal values. These nominal loads are based on assumed equipment vendor information and best engineering load estimates.
2 Also applicable to Division II 3 Momentary loads are de-energized by PPS in the event of a loss of AC power to the EDSS-C battery chargers.
NuScale Nonproprietary Response to Request for Additional Information Docket No.52-048 eRAI No.: 9038 Date of RAI Issue: 08/19/2017 NRC Question No.: 08.03.02-3 FSAR Tier 2 states in Section 8.3.2.1.1, Highly Reliable Direct Current Power System, that the EDSS-MS for an NPM provides electrical power for the MPS, other loads associated with that NPM. These loads are provided in FSAR Tier 2 Table 8.3-5, Highly Reliable Direct Current Power System - Module Specific Nominal Loads.
QUESTION: A footnote to FSAR Table 8.3-5 states: Charger-only loads are de-energized by MPS/PPS at the onset of the battery duty cycle. Please clarify what is meant by charger-only loads.
NuScale Response:
NuScale has reclassified the "charger only" loads of FSAR Table 8.3-5 as momentary loads consistent with Section 4.2 of IEEE Std. 485-1997 (FSAR Reference 8.3-12) and has revised the table to reflect this change.
The revision to FSAR Table 8.3-5 indicates that certain EDSS-MS are momentary loads. These loads are de-energized by the module protection system upon detection of a loss of AC power to the EDSS-MS chargers. The MPS logic that initiates this action is shown in FSAR Figure 7.1-1ah. As described in FSAR Table 7.1-3, there is an actuation delay of 60 seconds associated with this function. The 60 second delay is an analytical limit. As part of the final design phase, a time delay of less than one minute will be implemented to allow for automatic bus transfers to re-energize a bus before a reactor trip is processed. Consistent with Section 4.2.3 of IEEE Std. 485-1997, the momentary EDSS-MS loads are conservatively assumed to last for a full minute during the battery duty cycle.
The small increase in battery loading due to the additional minute to accommodate these momentary loads has no significant impact on the battery capacity margin. The EDSS-MS battery sizing calculations conservatively incorporate a design margin factor of 1.50. This design margin is intended to encompass potential load additions during NuScale plant design development (25%) and future load growth during plant operating life (25%).
NuScale Nonproprietary In addition to the momentary load reclassification changes, 1) a note has been added to FSAR Table 8.3-5 to clarify the basis for the load values, and 2) four Channel B and Channel C EDSS-MS loads were reclassified from continuous to noncontinuous.
This reclassification is consistent with Section 4.2 of IEEE Std. 485-1997 and with the duration of these loads as described in FSAR Section 7.0.4.1.4. There is no impact on the battery load profile associated with this change.
Impact on DCA:
FSAR Section 8.3.2.2.1 and FSAR Table 8.3-5 have been revised as described in the response above and as shown in the markup provided in this response.
NuScale Final Safety Analysis Report Onsite Power Systems Tier 2 8.3-30 Draft Revision 1 the standard commercially available equipment ratings. See Table 8.3-8 for the EDNS regulating transformer sizing per subsystem.
8.3.2.2 Design Evaluation 8.3.2.2.1 System Interfaces Highly Reliable DC Power System The ELVS provides AC power to the EDSS battery chargers. AC power to the ELVS is provided by the normal AC power sources (main generators, onsite AC distribution, or offsite transmission grid, if supplied) or by the BDGs.
The EDSS-C and EDSS-MS loads are listed in Table 8.3-4 and Table 8.3-5.
Additionally, the following systems receive highly reliable DC power from the EDSS:
RAI 08.03.02-3 Module Protection System - EDSS-MS channels A, B, C, and D provide electrical power to MPS separation groups A, B, C, and D equipment, respectively. The EDSS-MS Division I (channels A and C) and Division II (channels B and D) provide electrical power to Division I and Division II MPS equipment, respectively. When AC input power to EDSS-MS battery chargers is unavailable, the MPS loads are energized for 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> and PAM loads are energized for 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br /> as described in Section 7.0.4.1.4.
In addition to energizing required loads during the EDSS battery duty cycle, the MPS de-energizes unneeded loads. The MPS logic that de-energizes loads in the event of a loss of AC power to the EDSS-MS battery chargers is shown in Figure 7.1-1ah.
RAI 08.03.02-2 Plant Protection System (PPS) - The EDSS-C Division I and Division II provide electrical power to PPS Division I and Division II equipment, respectively. When AC input power to the EDSS-C battery chargers is unavailable, the PPS loads required to support PAM are energized for 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br /> by the EDSS-C batteries. In addition to energizing required loads during the EDSS battery duty cycle, the PPS de-energizes unneeded loads. The PPS logic that de-energizes loads in the event of a loss of AC power to the EDSS-C battery chargers is shown in Figures 7.1-3b and 7.1-3c.
Plant Lighting System - The EDSS-C provides electrical power to MCR emergency lighting. The battery chargers are sized to accommodate this load during normal operation and the batteries are sized to provide power for a minimum of 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br /> following a loss of normal AC power.
Safety Display and Indication System (SDIS) - The EDSS-C provides electrical power to NPM-specific and common-plant safety displays. The battery chargers are sized to accommodate the display loads during normal operation and the batteries are sized to provide power to these loads for a minimum of 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br /> following a loss of normal AC power.
NuScale Final Safety Analysis Report Onsite Power Systems Tier 2 8.3-49 Draft Revision 1 RAI 08.03.02-3 Table 8.3-5: Highly Reliable Direct Current Power System - Module Specific Nominal Loads Load Description Load on Charger -
only (W / amps)
Load on Battery (W / amps)
Time Period (hours)
Load Classification Amp - hour EDSS-MS Nominal Loads (Channel A)*
CVCS makeup containment isolation valve (CIV) 100.00 / 0.80 Charger-only***
CVCS letdown CIV 100.00 / 0.80 Charger-only***
CVCS pressurizer spray CIV 100.00 / 0.80 Charger-only***
CVCS high point degas CIV 100.00 / 0.80 Charger-only***
Main steam CIV 100.00 / 0.80 Charger-only***
Main steam bypass CIV****
0.00 / 0.00 Charger-only***
Decay heat removal system (DHRS) actuation valve 1 100.00 / 0.80 Charger-only***
DHRS actuation valve 2 100.00 / 0.80 Charger-only***
Containment evacuation system CIV 100.00 / 0.80 Charger-only***
Reactor component cooling water system (RCCWS) supply CIV 100.00 / 0.80 Charger-only***
RCCWS return CIV 100.00 / 0.80 Charger-only***
CFDS containment isolation valve 100.00 / 0.80 Charger-only***
Feedwater system CIV 100.00 / 0.80 Charger-only***
ECCS reactor recirculation valve 250.00 / 2.00 0-24 Continuous 48.00 ECCS reactor vent valve #1 250.00 / 2.00 0-24 Continuous 48.00 ECCS reactor vent valve #3 250.00 / 2.00 0-24 Continuous 48.00 MPS cabinet (SC/TD) 89.41 / 0.72 0-24 Continuous 17.28 MPS cabinet (gateway) 104.71 / 0.84 0-24 Continuous 20.16 MPS cabinet (RTS/ESFAS) 176.47 / 1.41 0-24 Continuous 33.84 MPS sensor input power 60.59 / 0.48 0-24 Continuous 11.52 NMS cabinet 100.00 / 0.80 0-24 Continuous 19.20 EDSS battery monitor 50.00 / 0.40 0-24 Continuous 9.60 Total continuous battery load 1331.18 / 10.65 Total charger - only load 1200.00 / 9.60 Actual amp - hours removed 255.60 EDSS-MS Nominal Loads (Channel C) **
CVCS makeup CIV 100.00 / 0.80 Charger-only***
CVCS letdown CIV 100.00 / 0.80 Charger-only***
CVCS pressurizer spray CIV 100.00 / 0.80 Charger-only***
CVCS high point degas CIV 100.00 / 0.80 Charger-only***
Main steam CIV 100.00 / 0.80 Charger-only***
Main steam bypass CIV****
0.00 / 0.00 Charger-only***
DHRS actuation valve 1 100.00 / 0.80 Charger-only***
DHRS actuation valve 2 100.00 / 0.80 Charger-only***
CES containment isolation valve 100.00 / 0.80 Charger-only***
RCCWS supply CIV 100.00 / 0.80 Charger-only***
RCCWS return CIV 100.00 / 0.80 Charger-only***
CFDS containment isolation valve 100.00 / 0.80 Charger-only***
Feedwater system CIV 100.00 / 0.80 Charger-only***
ECCS reactor recirculation valve 250.00 / 2.00 0-24 Continuous 48.00 ECCS reactor vent valve #1 250.00 / 2.00 0-24 Continuous 48.00 ECCS reactor vent valve #3 250.00 / 2.00 0-24 Continuous 48.00
NuScale Final Safety Analysis Report Onsite Power Systems Tier 2 8.3-50 Draft Revision 1 MPS cabinet (SC/TD) 118.82 / 0.95 0-72 Continuous 68.40 MPS cabinet (gateway) 104.71 / 0.84 0-72 Continuous 60.48 MPS cabinet (RTS/ESFAS) 176.47 / 1.41 0-24 Continuous 33.84 MPS sensor input power 60.59 / 0.48 0-72 Continuous 34.56 NMS cabinet 100.00 / 0.80 0-72 Continuous 57.60 RMS bioshield radiation monitor 120.00 / 0.96 0-72 Continuous 69.12 EDSS battery monitor 50.00 / 0.40 0-72 Continuous 28.80 Total continuous battery load 1480.59 / 11.84 Total charger - only load 1200.00 / 9.60 Actual amp - hours removed 496.80
- Also applicable to Channel D
- Also applicable to Channel B
- Charger-only loads are de-energized by MPS/PPS at the onset of the battery duty cycle.
- Main steam bypass CIVs are considered to be de-energized during normal operation Table 8.3-5: Highly Reliable Direct Current Power System - Module Specific Nominal Loads (Continued)
Load Description Load on Charger -
only (W / amps)
Load on Battery (W / amps)
Time Period (hours)
Load Classification Amp - hour
NuScale Final Safety Analysis Report Onsite Power Systems Tier 2 8.3-51 Draft Revision 1 RAI 08.03.02-3 Table 8.3-5: Highly Reliable Direct Current Power System - Module Specific Nominal Loads1 Load Description Load (W, amps)
Time Period Load Classification2 Amp-hour EDSS-MS Nominal Loads (Channel A)3 CVCS Makeup Containment Isolation Valve (CIV) 100.00 0.80 60 sec Momentary 0.01 CVCS Letdown CIV 100.00 0.80 60 sec Momentary 0.01 CVCS PZR Spray CIV 100.00 0.80 60 sec Momentary 0.01 CVCS High Point Degas CIV 100.00 0.80 60 sec Momentary 0.01 Main Steam CIV 100.00 0.80 60 sec Momentary 0.01 Main Steam Bypass CIV4 0.00 0.00 0.00 DHRS Actuation Valve 1 100.00 0.80 60 sec Momentary 0.01 DHRS Actuation Valve 2 100.00 0.80 60 sec Momentary 0.01 CES CIC 100.00 0.80 60 sec Momentary 0.01 RCCWS Supply CIV 100.00 0.80 60 sec Momentary 0.01 RCCWS Return CIV 100.00 0.80 60 sec Momentary 0.01 CFDS CIV 100.00 0.80 60 sec Momentary 0.01 FWS CIV 100.00 0.80 60 sec Momentary 0.01 ECCS Reactor Recirculation Valve (RRV) 250.00 2.00 24 hr Continuous 48.00 ECCS Reactor Vent Valve (RVV) #1 250.00 2.00 24 hr Continuous 48.00 ECCS Reactor Vent Valve (RVV) #3 250.00 2.00 24 hr Continuous 48.00 MPS Cabinet (SC/TD) 89.41 0.72 24 hr Continuous 17.28 MPS Cabinet (Gateway) 104.71 0.84 24 hr Continuous 20.16 MPS Cabinet (RTS/ESFAS) 176.47 1.41 24 hr Continuous 33.84 MPS Sensor Input Power 60.59 0.48 24 hr Continuous 11.52 NMS Cabinet 100.00 0.80 24 hr Continuous 19.20 EDSS Battery Monitor 50.00 0.40 24 hr Continuous 9.60 Total Continuous Load (ILC) 1331.18 10.65 Total Noncontinuous Load (ILN) 0.00 0.00 Total Momentary Load (ILM) 1200.00 9.60 Actual Amp-Hours Removed (Q) 255.72 EDSS-MS Nominal Loads (Channel C)5 CVCS Makeup CIV 100.00 0.80 60 sec Momentary 0.01 CVCS Letdown CIV 100.00 0.80 60 sec Momentary 0.01 CVCS PZR Spray CIV 100.00 0.80 60 sec Momentary 0.01 CVCS High Point Degas CIV 100.00 0.80 60 sec Momentary 0.01 Main Steam CIV 100.00 0.80 60 sec Momentary 0.01 Main Steam Bypass CIV4 0.00 0.00 0.00 DHRS Actuation Valve 1 100.00 0.80 60 sec Momentary 0.01 DHRS Actuation Valve 2 100.00 0.80 60 sec Momentary 0.01 CES CIV 100.00 0.80 60 sec Momentary 0.01 RCCWS Supply CIV 100.00 0.80 60 sec Momentary 0.01 RCCWS Return CIV 100.00 0.80 60 sec Momentary 0.01 CFDS CIV 100.00 0.80 60 sec Momentary 0.01 FWS CIV 100.00 0.80 60 sec Momentary 0.01 ECCS Reactor Recirculation Valve (RRV) 250.00 2.00 24 hr Noncontinuous 48.00 ECCS Reactor Vent Valve (RVV) #1 250.00 2.00 24 hr Noncontinuous 48.00 ECCS Reactor Vent Valve (RVV) #3 250.00 2.00 24 hr Noncontinuous 48.00 MPS Cabinet (SC/TD) 118.82 0.95 72 hr Continuous 68.40
NuScale Final Safety Analysis Report Onsite Power Systems Tier 2 8.3-52 Draft Revision 1 MPS Cabinet (Gateway) 104.71 0.84 72 hr Continuous 60.48 MPS Cabinet (RTS/ESFAS) 176.47 1.41 24 hr Noncontinuous 33.84 MPS Sensor Input Power 60.59 0.48 72 hr Continuous 34.56 NMS Cabinet 100.00 0.80 72 hr Continuous 57.60 RMS Bioshield Radiation Monitor 120.00 0.96 72 hr Continuous 69.12 EDSS Battery Monitor 50.00 0.40 72 hr Continuous 28.80 Total Continuous Load (ILC) 554.12 4.43 Total Noncontinuous Load (ILN) 926.47 7.41 Total Momentary Load (ILM) 1200.00 9.60 Actual Amp-Hours Removed (Q) 496.92 1 The loads assumed for each divisional battery are estimated nominal values. These nominal loads are based on assumed equipment vendor information and best engineering load estimates.
2 Momentary loads are de-energized by MPS in the event of a loss of AC power to the EDSS-MS battery chargers.
3 Also applicable to Channel D 4 Main steam bypass CIVs are considered to be de-energized during normal operation.
5 Also applicable to Channel B Table 8.3-5: Highly Reliable Direct Current Power System - Module Specific Nominal Loads1 (Continued)
Load Description Load (W, amps)
Time Period Load Classification2 Amp-hour
NuScale Nonproprietary Response to Request for Additional Information Docket No.52-048 eRAI No.: 9038 Date of RAI Issue: 08/19/2017 NRC Question No.: 08.03.02-4 In FSAR Tier 2, Table 8.3-7, Highly Reliable Direct Current Power System Failure Modes and Effects Analysis, NuScale provided an evaluation of EDSS component failures. The evaluation assumed that each component single failure occurs concurrently with the unavailability of the redundant EDSS channel. The results show that no failure prevents safety-related functions from being achieved and maintained. Additionally, under operating conditions, wherein all EDSS channels and divisions are available, no single failure results in inadvertent actuation of safety-related functions.
QUESTION: The NuScale application states that there is no safety-related AC or DC power.
However, the previous paragraph states: The results show that no failure prevents safety-related functions from being achieved and maintained. (emphasis added). Please explain what is meant by safety-related functions, if related to AC or DC power.
NuScale Response:
The quoted statement in this question, which is from FSAR Section 8.3.2.1.1, and FSAR Table 8.3-7 both pertain only to the Highly Reliable DC Power System (EDSS) and not to the onsite AC power systems or the Normal DC Power System (EDNS). Although not the subject of the FSAR statement or the failure modes and effects analysis (FMEA) in the question, the EDNS and the AC power systems also do not perform any safety-related functions as described in FSAR Section 8.3.
As described in FSAR Section 8.3.2, the EDSS does not perform any safety-related functions.
Although the EDSS does not perform any safety-related functions, it does provide power to safety-related loads that perform safety-related functions. The safety-related functions that were evaluated in the EDSS FMEA are those performed by the safety-related systems that interface with the EDSS as indicated by the entries in the conclusion column of FSAR Table 8.3-7. The EDSS interfaces are identified in FSAR Section 8.3.2.2.1. Consistent with FSAR Section 8.3.1.1.1, the FMEA results demonstrate that EDSS component failures do not prevent safety-related functions from being achieved and maintained.
NuScale Nonproprietary Impact on DCA:
There are no impacts to the DCA as a result of this response.
NuScale Nonproprietary Response to Request for Additional Information Docket No.52-048 eRAI No.: 9038 Date of RAI Issue: 08/19/2017 NRC Question No.: 08.03.02-5 In FSAR Tier 2 Table 8.3-7, Highly Reliable Direct Current Power System Failure Modes and Effects Analysis, under the Battery Charger Failure Mode of Erratic output, the following is stated: Redundant charger able to compensate on affected channel/division. The EDSS may operate at abnormal voltage levels.
QUESTION: Explain the function of the communication link between the two paralleled chargers.
NuScale Response:
FSAR Section 8.3.2.1.1 includes a description of this link. The description has been revised to more clearly describe its function. The communication link term used in FSAR Table 8.3-7 is consistent with the load-sharing circuit described in the attached revision to FSAR Section 8.3.2.1.1.
The inclusion of a load-sharing circuit is consistent with Section 6.5.3 of IEEE Standard 946-2004 (Reference 8.3-13).
Impact on DCA:
FSAR Section 8.3.2.1.1 has been revised as described in the response above and as shown in the markup provided in this response.
NuScale Final Safety Analysis Report Onsite Power Systems Tier 2 8.3-26 Draft Revision 1 Each battery in EDSS-MS Channel A (Division I) and Channel D (Division II) is sized for a 24-hour duty cycle. Each battery is rated 542 ampere-hours for a 24-hour discharge to a final voltage of 105 Vdc or 1.75 volts per cell.
Each battery in EDSS-MS Channel B (Division II) and Channel C (Division I) is sized for a 72-hour duty cycle. The EDSS-MS channels B and C batteries are rated 1039 ampere-hours for a 72-hour discharge to a final voltage of 105 Vdc or 1.75 volts per cell.
Each battery in EDSS-C Division I and Division II is sized for a 72-hour duty cycle.
These batteries are rated 2303 ampere-hours for a 72-hour discharge to a final voltage of 105 Vdc or 1.75 volts per cell.
The EDSS batteries are designed with margin to allow for future load growth, temperature correction, and battery aging. A conservative design margin factor of 1.50 is applied to account for potential load additions during design development (25 percent) and future load growth during plant operating life (25 percent). The temperature correction factor used is 1.11, which correlates to a minimum temperature of 60 degrees F. The battery aging factor used is 1.25.
Highly Reliable Direct Current Power System Battery Chargers RAI 08.03.02-5 Each EDSS-C and EDSS-MS battery charger capacity is sufficient to supply power to the connected steady-state loads under maximum loading conditions, while at the same time recharging the associated batteries from the design minimum charge state to 95 percent of full charge within 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br />. The two battery chargers in each EDSS-C division and in each EDSS-MS channel are normally operated in parallel.
Battery charger linkage facilitates sharing the division and channel electrical loads equallyThe parallel chargers are linked by a load-sharing circuit, which does not rely on software-based technology. The circuit provides for output balancing and is consistent with IEEE 946-2004 (Reference 8.3-13).
The EDSS battery chargers are sized using the guidance of IEEE Standard 946-2004 (Reference 8.3-13). Input voltage to the EDSS battery chargers is 480 Vac, 3 phase.
The DC output voltage is 125 Vdc. See Table 8.3-3 for EDSS battery charger sizing per subsystem.
The EDSS battery chargers have individual controls to manually select float and equalize modes, and to accurately adjust float and equalize voltages within the range recommended by the battery manufacturer. The EDSS battery rooms are maintained as mild environments. When this type of environment is combined with temperature-compensated battery charger output, the risk of a battery thermal runaway condition is reduced during charging of the VRLA batteries. The parallel connection of the EDSS batteries to the chargers allows for the batteries to automatically assume the loads for a loss of AC power to the chargers. Battery chargers include blocking features in their design to prevent their AC source from becoming a load on the batteries.
NuScale Nonproprietary Response to Request for Additional Information Docket No.52-048 eRAI No.: 9038 Date of RAI Issue: 08/19/2017 NRC Question No.: 08.03.02-6 In FSAR Tier 2, Table 8.3-7, Highly Reliable Direct Current Power System Failure Modes and Effects Analysis, under the Battery Charger Failure Mode of Loss of blocking functionality, the following is stated: Redundant charger available to compensate on affected channel/division.
Assumes forward current flow is not permitted through affected charger.
QUESTION: Please clarify the statement: Assumes forward current flow is not permitted through affected charger. Did forward current actually meant backward current that is not permitted from the battery to the charger upon failure of the affected charger?]
NuScale Response:
In the loss of blocking functionality failure mode in FSAR Table 8.3-7, 'forward current' through the affected charger should be construed as from the affected charger to the bus. The assumption that there is no forward current flow from the affected charger is conservative in that it distinguishes the blocking failure mode from the low charger output failure mode that has less severe effects.
The scenario assumes a failure of the charger blocking feature that prevents the charger AC source from becoming an upstream load on the batteries as described in FSAR Section 8.3.2.1.1. The assumption that the normal EDSS AC power supply is not available during the blocking failure, as indicated by the asterisk (*) and the B) condition in FSAR Table 8.3-7, results in a loss of the parallel charger's output. The battery becomes the sole remaining DC power source to the affected bus in this conservative scenario.
In the blocking failure mode analysis, reverse (or backward) current through the affected charger from the battery to an upstream load is assumed to be of sufficient magnitude to adversely affect the duty cycle. Even in the unlikely scenario that the duty cycle effect leads to a loss of power to the safety load, the blocking failure does not result in a loss of the interfacing safety system functions as described in the conclusion section for this failure mode.
NuScale Nonproprietary Impact on DCA:
There are no impacts to the DCA as a result of this response.
NuScale Nonproprietary Response to Request for Additional Information Docket No.52-048 eRAI No.: 9038 Date of RAI Issue: 08/19/2017 NRC Question No.: 08.03.02-7 In the FSAR Tier 2, Section 8.3.2.2.2, regarding GDC 2, the applicant stated as follows: The EDSS structures, systems, and components are principally located in the CRB and RXB, which are designed to withstand the effects of and function following natural phenomena such as earthquakes, tornadoes, hurricanes, floods, and externally-generated missiles.
QUESTION: Please explain what is meant by principally located in the Control Building (CRB) and Reactor Building (RXB). In Reference 8.3-1 [NuScale Power, LLC, "Safety Classification of Passive Nuclear Power Plant Electrical Systems," TR-0815-16497-P, Rev.0], Table 3-2, Augmented design, qualification, and quality assurance provisions, the following is stated:
[t]he highly reliable DC electrical systems (including the batteries) are housed in SC-I structures designed to provide protection from environmental hazards. Clarify whether any components of EDSS will be located in buildings which are not environmentally qualified (i.e., outside the CRS and RXB).
NuScale Response:
FSAR Section 8.3.2.2.2 has been revised to remove the term principally and to indicate that the EDSS SSC are located in the Seismically Category I portions of the CRB (below the 120 ft elevation) and in the RXB, which is a Seismic Category I structure.
Impact on DCA:
FSAR Section 8.3.2.2.2 has been been revised as described in the response above and as shown in the markup provided in this response.
NuScale Final Safety Analysis Report Onsite Power Systems Tier 2 8.3-31 Draft Revision 1 control rod drive system feedwater treatment system main steam system site cooling water system gaseous radioactive waste management system condensate and feedwater system CHWS utility water system demineralized water system nitrogen distribution system module assembly equipment health physics network Reactor Building HVAC system (RBVS) fire protection system fire detection system PLS for approximately one-third of the plant lights plant control system module control system PPS for non-safety loads RMS in-core instrumentation system meteorological and environmental monitoring system communication system plant-wide video monitoring system seismic monitoring system EDNS battery room ventilation systems post-accident type E variable control and instrumentation loads turbine generator system emergency DC lube oil pumps 8.3.2.2.2 Onsite Direct Current Power System Conformance with Regulatory Framework This section describes the extent to which the design of the onsite DC power systems, including the EDSS and the EDNS electrical equipment, conforms to NRC requirements and guidance. As such, the information in this section provides clarification for the associated entries in Table 8.1-1 of Section 8.1.
RAI 08.03.02-7
NuScale Final Safety Analysis Report Onsite Power Systems Tier 2 8.3-32 Draft Revision 1 GDC 2 The EDNS is not required to function in the event of natural phenomena events.
The EDNS structures, systems, and components with the potential for adverse seismic interaction with Seismic Category I SSC are designed to Seismic Category II requirements so that their failure does not affect the ability of a safety-related SSC to perform its intended function. The EDSS structures, systems, and components are designed with augmented requirements for protection from the effects of natural phenomena for increased reliability and availability. The EDSS structures, systems, and components are principally located in the CRB and RXBlocated in the RXB and in areas of the CRB below the 120 ft elevation, which are designed to withstand the effects of and function following natural phenomena such as earthquakes, tornadoes, hurricanes, floods, and externally-generated missiles.
The EDSS structures, systems, and components are further augmented by applying design, qualification, and QA provisions typically applied to Class1E DC power systems using a graded approach. The graded approach is reflected in the EDSS design, qualification, and QA provisions detailed in Reference 8.3-1. Specific to seismic phenomena, Reference 8.3-1 includes augmented seismic design and qualification provisions.
GDC 4 The EDSS design accommodates the effects of environmental conditions by applying augmented provisions for the design, qualification, and QA typically applied to Class1E DC power systems using a graded approach. The graded approach is reflected in the EDSS design, qualification, and QA provisions detailed in Reference 8.3-1. The physical locations of the EDSS-MSs and EDSS-C within the Seismic Category I RXB and CRB, respectively, provide the EDSS with protection from dynamic effects, including the effects of missiles, pipe whipping, and discharging fluids.
GDC 5 As shown on Figure 8.3-7a and Figure 8.3-7b, the EDSS-MS is not shared between NPMs thus satisfying the intent of RG 1.81, Position C.1. Specifically, portions of the EDSS that supply electrical power to the MPS are not shared. This is achieved by providing each NPM with a dedicated EDSS-MS.
Sharing of the EDSS-C is shown on Figure 8.3-6. A postulated loss of or power fluctuation on the EDSS-C would not result in adverse interactions between NPMs, and would not impair the performance of safety-related functions necessary to achieve and maintain safe shutdown in all NPMs.
As shown on Figure 8.3-8a through Figure 8.3-8f, the EDNS consists of the EDNSs located throughout the NuScale Power Plant. A failure in these systems does not impair the ability to achieve and maintain safety-related functions for any NPM.