NL-13-1648, Response to Supplemental Information Needed for Acceptance of License Amendment Request for Technical Specification 3.7.14 Completion Time

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Response to Supplemental Information Needed for Acceptance of License Amendment Request for Technical Specification 3.7.14 Completion Time
ML13220A946
Person / Time
Site: Vogtle  Southern Nuclear icon.png
Issue date: 08/07/2013
From: Pierce C
Southern Nuclear Operating Co, Southern Co
To:
Office of Nuclear Reactor Regulation, Document Control Desk
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ML13220B048 List:
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NL-13-1648
Download: ML13220A946 (28)
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Text

Charles R. Pierce Southern Nuclear Re gu latory Affairs Director Operating Company, Inc.

40 Inverness Center Parkway Post Office Box 1295 Birmin gham, Alabama 35201 Tel 205.992.7872 Fax 205.992.7601 August 7, 2013 SOUIHERN A Docket Nos.: 50-424 COMPANY 50-425 U. S. Nuclear Regulatory Commission NL-13-1648 ATrN : Document Control Desk Washington, D. C. 20555-0001 Vogtle Electric Generating Plant Response to Supplemental Information Needed for Acceptance of License Amendment Request for Technical Specification 3.7.14 Completion Time Ladies and Gentlemen :

By letter dated September 26, 2012, Southern Nuclear Operating Company (SNC), submitted a license amendment request (LAR) to revise the Completion Time (CT) for Technical Specification (TS) 3.7.14, "Engineered Safety Features (ESF) Room Cooler and Safety Related Chiller System." The LAR proposes to revise the CT for Condition A, "One ESF room cooler and safety-related chiller train inoperable," from "72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br />" to "7 days OR 14 days for chiller overhaul maintenance." By letter dated April 26, 2013, the U. S. Nuclear Regulatory Commission (NRC) staff requested supplemental information to enable the staff to begin its detailed technical review. to this document provides SNC's response to the NRC's April 26, 2013 letter. Based on discussions subsequent to the LAR submittal, SNC is revising the TS amendment request to no longer request 14 days for chiller overhaul maintenance. Enclosure 2 contains the revised marked-up TS and TS Bases pages. Enclosure 3 contains the revised clean typed TS page. Based on the proposed changes , SNC is withdrawing the commitments listed in Enclosure 4 of the September 26,2012 LAR and issuing new commitments. The new commitments are listed in Enclosure 4 of this letter. Due to the nature of the differences between the proposed TS and TS Bases changes in the September 26,2012 LAR and the proposed changes in this letter, the "Significant Hazards Consideration" given in Section 4.1 of the September 26, 2012 LAR remains valid. Enclosure 5 contains requested drawings per NRC question 1b. Please note that the originals of the drawings provided in Enclosure 5 contain the following statement:

"This document contains proprietary, confidential, and/or trade secret information of the subsidiaries of the Southern Company or of third parties. It is intended for use only by employees of, or authorized contractors of, the subsidiaries of the Southern Company. Unauthorized possession , use, distribution , copying , dissemination, or disclosure of any portion hereof is prohibited ."

U. S. Nuclear Regulatory Commission NL~13~1648 Page 2 SNC does not request exclusion from the public domain via 10 CFR 2.390 for these drawings. For Enclosure 5 of this letter, the drawings have been modified to not include the above statement.

This letter supersedes SNC letter NL~ 13~0972, dated June 24, 2013, in its entirety.

This letter contains NRC commitments (reference Enclosure 4). If you have any questions, please contact Ken McElroy at (205) 992~ 7369.

Mr. C. R. Pierce states he is Regulatory Affairs Director of Southern Nuclear Operating Company, is authorized to execute this oath on behalf of Southern Nuclear Operating Company and, to the best of his knowledge and belief, the facts set forth in this letter are true.

Respectfully submitted,

t. Ii. ~

C. R. Pierce Regulatory Affairs Director CRP/RMJ efore me this 1 t1-- day of Llu ~ f ,2013.

---+==~~~~~~~

~~

My commission expires: / /- 6 Z. - 2.0 13

Enclosures:

1. SNC Response to April 26, 2013 NRC Letter
2. Revised Marked~Up Technical Specification and Bases Pages
3. Revised Clean Typed Technical Spedfication Page
4. Commitment Table
5. Requested Drawings cc: Southern Nuclear Operating Company Mr. S. E. Kuczynski, Chairman, President & CEO Mr. D. G. Bost, Executive Vice President & Chief Nuclear Officer Mr. T. E. Tynan, Vice President - Vogtle Mr. B. L. Ivey, Vice President - Regulatory Affairs Mr. B. J. Adams, Vice President - Fleet Operations RType: CVC7000 U. S. Nuclear Regulatory Commission Mr. V. M. McCree, Regional Administrator Mr. R. E. Martin, NRR Senior Project Manager ~ Vogtle Mr. L. M. Cain, Senior Resident Inspector - Vogtle State of Georgia Mr. J. H. Turner, Environmental Director Protection Division

VogUe Electric Generating Plant Response to Supplemental Information Needed for Acceptance of Amendment Request for Technical Specification 3.7.14 Completion Time Enclosure 1 SNC Response to April 26, 2013 NRC letter to NL-13-1648 SNC Response to April 26, 2013 NRC Letter NRC Question 1 Please provide a complete description of the engineered safety feature (ESF) Essential Chilled Water/Room Cooler System, as follows:

NRC Question 1a Provide a listing of all ESF room coolers/air handling units in the system. If Enclosure 6 to the LAR constitutes such a list, clarify that there is a total of 14 room coolers per train, with several room coolers serving multiple rooms, such as for example 2-1532-A7-002-000 and 2-1561-E7 -001-000. Clarify why train 2B lists 13 room coolers whereas trains 1A, 1B, and 2A list 14 room coolers.

SNC Response to NRC Question 1a Enclosure 6 of the LAR provides a listing of all ESF room coolers / air handling units in the system. Each chiller system train serves 14 room coolers, with the exception of the 2B chiller system train, which only serves 13 room coolers. This is because trains 1A, 1B, and 2A have an additional room cooler not present in train 2B. The additional room cooler in trains 1A (1-1539-A7-005-000) and 2A (2-1539-A7-005-000) serves the separate Control Building Normal AC Room in Units 1 and 2, respectively. The additional room cooler in train 1B (1-1539-A7-006-000), serves the Control Building Electrical Equipment Room, which is a common area. Train 2B does not contain a room cooler that serves either of these areas.

Certain room coolers, such as 2-1532-A7-002-000 and 2-1561-E7-001-000, are designed such that they service multiple rooms.

NRC Question 1 b Provide piping and instrumentation drawings and floor location drawings showing each room cooler in the system .

SNC Response to NRC Question 1b The requested piping and instrumentation drawings are provided in Enclosure 5. The requested floor plan drawings will be provided in a separate letter at a later date.

NRC Question 1c The Bases for TS 3.7.14, states in part, the following:

The ESF room cooler and safety-related chiller system provides COOling to ESF equipment rooms during abnormal, accident, and post accident conditions. The ESF room coolers supplement the normal HVAC system in cooling certain rooms during normal operations. The essential chilled water system supplies chilled water to the cooling coils for all ESF room coolers and the Control Room Emergency Filtration System (CREFS) ....

In addition to a manual start capability, automatic cooling of each ESF equipment room is initiated by three possible signals. All room coolers start upon receipt of a high temperature signal from the associated room. Certain room coolers will start upon receipt of an equipment running signal or a safety injection (SI) signal. The equipment E1-1 to NL-13-1648 SNC Response to April 26, 2013 NRC Letter running signal is used to provide supplemental cooling for the normal ventilation system in some ESF equipment rooms. The high room temperature signal supplements the normal cooling system function and does not constitute a credited safety function. The SI signal or the equipment running signal is the credited safety function automatic start and will start only those ESF room coolers which are required to operate during an SI. In addition the safety-related chillers receive an automatic start from the Control Room Isolation (CRI) signal to provide chilled water to the CREFS. In addition, the containment spray pump room coolers start when the containment spray pumps start. Containment spray is actuated when containment pressure reaches the Hi-3 set point, which may occur following a loss of coo/ant accident or a steam line break.

This could imply that some of the room coolers in the ESF chiller/room cooler system are not required in response to accidents and transients as analyzed in the VEGP USFAR. For each of the room coolers/AHUs listed in response to item 1.a above, identify the UFSAR transient, accident analysis or condition for which its function is required . Also include identification of what start Signal each room cooler/AHU responds to.

SNC Response to NRC Question 1c The design basis of the ESF room cooler and safety-related chiller system is to maintain air temperatures as required in rooms containing safety-related equipment during and after a design basis loss of coolant accident (LOCA), loss of offsite power (LOSP), and other postulated accidents including a line rupture with a radioactive release inside the auxiliary building . The ESF room cooler and safety-related chiller system are required to automatically start when the systems or components it supports are required to operate following a Safety Injection (SI) or Control Room Isolation (CRI) signal. The safety-related chiller system is manually started following a LOSP. The system is designed to perform its function with a single failure of any active component, assuming the loss of offsite power. One train of the ESF room cooler and safety-related chiller system provides 100% of the required cooling for the associated train of ESF equipment.

Considering the applicability of specification LCO 3.7.14 is MODES 1 through 4, the bounding accident or event for the ESF Chiller and ESF Room Cooler trains is the requirement to perform the credited safety function following a large break LOCA.

Therefore, the ability to perform the safety function is required in the event of a SI in which Containment pressure reaches the Hi-3 setpoint of 21.5 pSig.

The only room cooler that does not perform a credited safety function in response to a large break LOCA is the Fuel Handling Building Spent Fuel Pool Heat Exchanger and Pump Room cooler. This subsystem is a defense in depth system that does not perform a credited safety function for the accidents and events analyzed for LCO 3.7.14.

The following table identifies the specific start signals for each of the components provided in the previous submittal. Please note that Unit 2 equipment is redundant to Unit 1 in regards to safety feature and start signal; therefore, only Unit 1 equipment data is provided.

E1-2

Enclosure 1 to NL-13-1648 SNC Response to April 26, 2013 NRC Letter Unit 1 Train A ESF Room Cooler Area Served Credited Safety Non-credited Start Signal Related Start Signal 1-1531-N7-001 -000 Main Control Room (Common to Units 1 and 2) CRI 1-1532-A 7-001-000 Control Building battery Rooms, MCC Room, SI Switchgear Rooms, and Shutdown Panel Rooms 1-1539-A7-001-000 Control Building Auxiliary Relay Room SI 1-1555-A7-001-000 Auxiliary Building Electrical Switchgear and MCC SI High Room Temp Room 1-1555-A 7 -003-000 Auxiliary Building Electrical Switchgear and MCC SI High Room Temp Room 1-1555-A7-005-000 Auxiliary Building Electrical SWitchgear and MCC Sl High Room Temp Room 1-1555-A7-007-000 Auxiliary Building Residual Heat Removal Pump Room Pump Start High Room Temp 1-1555-A 7 -009-000 Auxiliary Building Containment Spray Pump Room Pump Start High Room Temp 1-1555-A7-011-000 Auxiliary Building Component Cooling Water Pumps SI High Room Temp Room 1-1555-A7 -013-000 Auxiliary Building Chemical and Volume Control Pump Start High Room Temp System Pump Room 1-1555-A7 -015-000 Auxiliary Building Safety Injection System Pump Room Pump Start High Room Temp 1-1555-A7-017-000 Fuel handling Building Spent Fuel Pool Heat SI High Room Temp Exchanger and Pump Room (no credited safety function) 1-1561-E7-001-000 Piping Penetration Area CVI 1-1539-A7-005-000 Control Building Normal AC Room SI High Room Temp

- - - - - -- - - - - - - - - - -- I E1-3 to NL-13-1648 SNC Response to April 26, 2013 NRC Letter Unit 1 Train 8 ESF Room Cooler Area Served Credited Safety Non-credited Start Signal Related Start Signal 1-1531-N7-002-000 Main Control Room (Common to Units 1 and 2) CRI 1-1532-A7 -002-000 Control Building battery Rooms, MCC Room, SI SWitchgear Rooms, and Shutdown Panel Rooms 1-1539-A7-002-000 Control Building Auxiliary Relay Room SI 1-1555-A7 -002-000 Auxiliary Building Electrical Switchgear and MCC SI High Room Temp Room 1-1555-A7-004-000 Auxiliary Building Electrical Switchgear and MCC SI High Room Temp Room 1-1555-A7 -006-000 Auxiliary Building Electrical Switchgear and MCC SI High Room Temp Room 1-1555-A7-008-000 Auxiliary Building Residual Heat Removal Pump Room Pump Start High Room Temp 1-1555-A7 -010-000 Auxiliary Building Containment Spray Pump Room Pump Start High Room Temp 1-1555-A7-012-000 Auxiliary Building Component Cooling Water Pumps SI High Room Temp Room 1-1555-A7-014-000 Auxiliary Building Chemical and Volume Control Pump Start High Room Temp System Pump Room 1-1555-A7-016-000 Auxiliary Building Safety Injection System Pump Room Pump Start High Room Temp 1-1555-A 7-018-000 Fuel handling Building Spent Fuel Pool Heat SI High Room Temp Exchanger and Pump Room (no credited safety function) 1-1561-E7-002-000 Piping Penetration Area CVI 1-1539-A 7-006-000 Control Building Normal AC Room SI High Room Temp E1-4 to NL-13-1 SNC Response to April 3 NRC Letter NRC Question 1d Discuss mission time for the ESF chiller/room cooler system. If other coolers have a time than the period of thirty in BASES 3.7.10 please time(s). Please discuss this with to each room cooler/AHU in the chiller/cooler system.

The design basis of the room cooler and safety-related chiller temperatures as required in rooms containing safety-related design basis LOCA, offsite power, and other postulated aC(:lcemtS rupture with a radioactive inside the auxiliary building.

time for the ESF chiller/room cooler system is not explicitly of the Bases. chiller/room cooler systems are credited in ambient air temperature within the duty rating of the in each room. It can therefore be chiller/room cooler systems capable, as needed, to room temperatures for the duration that supported systems must perform their function. Safety related active mechanical equipment supported by Chiller and Room Cooler Train can be required to operate continuously following a accident (DBA). post-accident operating time for equipment included within the scope of the equipment qualification (EO) program is one year. Many of the rooms served by room contain EO equipment. FSAR 1.N.1.3 provides additional regarding required eqUipment operability the FSAR, Westinghouse supplied Class 1E electrical and active eqUipment located outside is accessible, and can be repaired, or recalibrated generally has a post-accident operability time of two WFH~KS NRC Question 2 The LAR states room coolers are designed to maintain the ambient air temperature below the environmental qualification rating of the equipment served by the system." For each cooler, provide a discussion of the structure, or component (SSG) protected by that cooler, eqUipment qualification limit and the that limit determined in the licensing basis for both cases of chiller in operation and the chiller being inoperable during the extended CT as proposed by the Include the time after initiation of the event that temperature occurs.

The fonowing tables room name, the calculated abnormal for each room, and the room's equipment qualification (EO) limit. Abnormal f'nr,rlit,,!"\nc: sets of plant conditions, including a loss normal cooling, for which the equipment is OC:II"1nt:1/"1 to operate for a period of time. Abnormal are calculated for rooms 1E equipment. The criteria abnormal environmental are as follows:

  • A loss of heating, and air-conditioning (HVAC) is when there is a failure of either the "",c-rom airflow (fan failure) or system cooling capability (chilled water).

E1-5 to NL-1 648 SNC Response to April 3 Letter

  • The initial temperature in spaces is assumed to design temperature used in the HVAC load (typically 100°F).
  • For calculation ,rnncoc the maximum duration of the I./U..,LU' loss of HVAC is 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br />.
  • Each room containing 1E equipment is analyzed for a normal HVAC during normal operation at full load with all normal heat sources operating.
  • Analysis is performed on a CIOlsea room or area basis, no airflow in or out of the room.
  • For those rooms <':I'>n,/I'>" HVAC systems, it is that system is activated HVAC. Analysis is performed normal heat sources operating in the room using the HVAC system's removal capacity for a period of 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br />.

results of the calculation for abnormal temperature were to determine many of the appropriate temperatures for the abnormal temperature limit. The "margin to the limit" is therefore not applicable for these cases. VEGP does not have limits that are based on both the loss of both normal emergency cooling for an of time. Given the similarities between Unit 1 Unit only Unit 1 data is shown below. calculations performed in support of the probabilistic risk assessment (PRA) are in the response to Question 4.

E1-6

Unit 1 Train A Abnormal EQ Abnormal ESF Room Cooler Room Number Heatup Results Limit SSC Area Served of (Note 2)

Main Control Room 156, 158,

-- 85 H531-N7-001-000 161,162,164) Main Control Room IIIIIUI to Units 1 and 2) 160 93 93 163 76 85 B84 75 100 Control Building Non-ESF DC Room B76 86 86 Control ing SWlll.ihgear Room B79 85 100 Control ing MCC Room B60 90 100 Control Building HVAC Train "AU B56 76 76 Control Building Train "C" Channel 3 1 -1532-A7-001-000 855 95 100 Control 19 Train "C* Channel 3 .

B54 80 80 Control ing Train "Au Channell 852 85 100 Control ing Train "An Channell A48 100 100 Control jng S'vv""hgear Train uN A75 76 76 Control Building Shutdown Room Train uN I 1 -1539-A 7-001-000 A45 81 100 Control ing Auxiliary Relay Room 1 -1555-A7-001-000 D105 < 120 120 Building Electrical Switchgear and Motor Control Center Room 1 -1555-A 7 -003-000 Cl09 < 120 120 Electrical :::' "l:j' and Motor Control Center Room 1 -1555-A7-005-000 118 < 120 120 Building Electrical SwitclIgear and Motor Control Center Room 1 -1555-A 7 -007 -000 D48 < 120 120 Auxiliary Building Residual Heat Removal Pump Room 1 -1555-A 7-009-000 D76 < 120 120 Auxiliary ing Containment Spray Pump Room E1-7 to NL-1 SNC Response April 3 Unit 1 Train A EQAbnormal ESF Room Cooler I Room Number I Heatup Results I Temp Limit I SSC Area Served of I

1 -1555-A7-011-000 A05 < 120 I 120 1 -1555-A7-013-000 C115 < 120 1 -1555-A7-015-000 B15 < 120 1 -1555-A7-017-000 A53 < 120 Room Series of 1 -1561-E7-001-000 Rooms - v u,s n ... o \j ,,,,on,,,",,

1)

Pip ina Penetration Area 1-1539-A7 -005-000 I 325 118 118 Control Normal AC Room Note 1: Drawing 1 X4DB205-2 lists ali rooms located within the piping penetration area. Calculation X4C1500S20 determines that all rooms within the piping penetration area are maintained below the environmental qualification abnormal limit.

Note 2: All heatup result values from calculation X4C1500S20 E1 to NL-13-1648 SNC Response to April 26, 2013 NRC Letter Unit 1 Train B Abnormal EQ Abnormal ESF Room Cooler Room Number Heatup Results Area Served Temp Limit of (Note 2) of Main Control Room (Rooms 156,157, 158,

-- 85 1 -1531-N7-002-000 161,162, 164) Main Control Room (Common to Units 1 and 2) 160 93 93 163 76 85 B62 90 100 Control Building HVAC Train "B' B61 86 100 Control Building Switchgear B53 - 80 Control Building Non-Train D.C.Room B44 74 80 Control Building Train "D" Channel 4 B48 100 100 Control Building Train 'D" Channel 4 1 -1532-A 7 -002-000 B47 92 92 Control Building ESF & Channel 2  !

849 75 80 Control Building Train ' B" Channel 2 I A50 97 100 Control Building Switchgear Train"B" A77 75 100 Control Building MCC Room A43 72 80 Control Building Shutdown Room Train "B" 1 -1539-A 7-002-000 226 75 100 Control Building Auxiliary Isolating Relay Room 1 -1555-A 7-002-000 207 < 120 120 Auxiliary Building Electrical Switchgear and Motor Control Center Room 1 -1555-A 7 -004-000 B16 < 120 120 Auxiliary Building Electrical Switchgear and Motor Control Center Room 1 -1555-A 7-006-000 116 < 120 120 Auxiliary Building Electrical Switchgear and Motor Control Center Room 1 -1555-A 7-008-000 D49 < 120 120 Auxiliary Building Residual Heat Removal Pump Room 1 -1555-A 7-010-000 D77 < 120 120 Auxiliary Building Containment Spray Pump Room 1 -1555-A7-012-000 A03 < 120 120 Auxiliary Building Component Cooling Water Pumps Room E1-9 to SNC Response to 3 NRC Unit 1 Train B Abnormal EQ Abnormal ESF Room Cooler Room Number Results Area Served Temp limit of

2) of Chemical and Volume Control System 1 -1555-A7-014-000 C118 < 120 120 1 -1555-A7-016-000 819 < 120 120

-1555-A 7 -0 18-000 108 108 Room Series of 1 -1561-E7 -001-000 Varies, Rooms

-1539-A7 -006-000 322 77 100 1X4DB205-2 lists all rooms located within the penetration area. determines that all rooms within the penetration area are maintained the environmental , .

Note 2: All result for ESF room cooler 1-1555-A7-018-000, are from calculation X4C1500S20. ESF room cooler 1-1555-A7-018-000 result is from calculation E1-10 to NL-13-1648 SNC Response to April 26, 2013 NRC Letter NRC Question 3 Compensatory Measures NRC Question 3a Compensatory measures are proposed for the duration of TS 3.7.14 Condition A for overhaul maintenance. Are compensatory measures proposed for the extension to 7 days?

As such, please describe these additional compensatory measures.

SNC Response to NRC Question 3a The compensatory measures provided in Enclosure 4 of the SNC LAR dated September 26, 2012, were originally only intended to support 14-day overhaul maintenance, and not for the 7 day required action statement completion time. However, SNC is revising this amendment request to require compensatory measures to be active within 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br /> of entering Condition A. These compensatory measures will remain in effect until the time that Condition A is exited. SNC is no longer requesting the Condition A 14-day completion time for chiller overhaul maintenance. See Enclosure 2 to this letter.

NRC Question 3b Discuss plans for the provision of a governing requirement for implementation of compensatory measures such as inclusion in the TS Bases, the UFSAR or in the TS Administrative Controls section.

SNC Response to NRC Question 3b SNC is revising this amendment request to include the compensatory measures as part of the Configuration Risk Management Program (CRMP). The CRMP is controlled per Section 5.5.18 of the Vogtle Technical Specifications. Site procedure(s) implementing CRMP will be revised to direct implementation of the compensatory measures as risk management actions within 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br /> of entering LCO 3.7.14 Condition A. The current CRMP model does not model the opening of doors as a risk mitigating measure.

NRC Question 3c Discuss the basis for the assumed effectiveness of the compensatory measures. For example, regarding the placement of fans, discuss prior experience that supports that the fans would have the desired result on room temperatures during abnormal, accident, and post accident conditions.

SNC Response to NRC Question 3c SNC is able to quantify the effect of opening doors on the expected peak room temperature.

Westinghouse heatup calculations supporting PRA model development provide the heatup results for electrical room R-B47 with and without credit taken for opening doors. R-B47 is a representative DC electrical room containing sensitive electrical equipment, and has the highest calculated temperature of the DC electrical rooms that are modeled. Without credit for opening doors, this room has a calculated peak temperature of 159.1 of at 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br />, and 183.3 of at 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br />. With credit taken for opening doors, this room has a calculated temperature of 91.1 of at 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br />, and 96.2 OF at 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br />. As stated in the Enclosure 4 E1-11 to NL-13-1648 SNC Response April 26, 2013 NRC Letter list of regulatory commitments, for safety related 125VDC 120VAC equipment rooms on affected train, equipment room doors will be propped open within hours of entering Condition A Although placement of is another method that can be to reduce room temperature if it is currently not procedurally required, nor benefits quantified. SNC is revising the commitments originally provided in the Amendment Request dated September 2012 to no longer specify placement of It is important to that, although the compensatory measures given in Enclosure 4 will be implemented within 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br /> entering Condition A, reliance on compensatory measures would only be required if the non-safety Normal Chilled Water System is not available concurrently with the inoperable Chiller and Room Cooler Train.

compensatory measures are being established as defense-in-depth to the overall risk.

The 4 Table actions to taken if the remaining ESF Discuss the required by 4, Condition B in this case with this represents a 3.0.3 condition.

If both Chiller Room Cooler are inoperable on a single unit, Specification Limiting Condition for Operation (LCO) would apply. Appropriate actions would be LCO 3.0.3. 4 Condition B applies when a ESF room cooler and safety-related chiller train cannot recovered to operable status within the specified Completion Time upon entering Condition A NRC Question 4 Assessment Provide a list of rooms addressed by the following "Room heat-up evaluations were performed every room that contains PRA credited components." Identify any rooms with equipment having a safety function that are not evaluated by a calculation. How is the impact of heat-up determined in these rooms and what is the time to action?

identify specific action how long the must maintained.

As part of PRA development task, room evaluations were conducted for all Unit 1 rooms containing credited accident initiating and equipment.

rooms listed in table are included in the scope of a heat-up calculation performed in support of the PRA to similarities in the room between Unit 1 and Unit 2 rooms, the of the Unit 1 heat-up are judged be applicable to the Unit 2 rooms. A listing of Unit 1 rooms served by room coolers that contain PRA credited initiating mitigating equipment for which evaluations were conducted follows in Table

-12 to NL-13-1648 SNC to April 26, 2013 NRC Letter Certain rooms served by the piping penetration filtration and exhaust system are the only rooms with equipment having a safety function for which a heat-up calculation was not identified. piping penetration filtrations and exhaust serves various rooms within the auxiliary building. The piping penetration filtrations and exhaust system is cooled by the chilled water system and by Nuclear Cooling Water (NSCW). On loss of ESF chilled water cooling, the NSCW would continue to provide cooling to the rooms served by the piping penetration filtration and exhaust system. As a result, heatup calculations for these rooms are not needed. There are no additional compensatory actions necessary the piping penetration filtrations and exhaust system on of chilled water.

4a-1 A-A50 4l60V SWGA 1BA03 Tr.

A*B76 480V SWGAs 1AB04, 1AB05 & MCC 1ABC A-D105 480V SWGA 1AB15 A*B61 A*207 480V SWGA 1BB16 A-325 480V MCC 1ABA A*118 480V MCC Inverter 1AD 1111 A-C109 480V MCC 1ABD A*B79 480V MCC 1ABE A-322 480V MCC 1BBA

  • A*116 480V MCC 1 Inverter 1BD1112 A*B16 480V MCC 1BBD A-A77 480V MCC 1BBE 125V DC Bus 1AD1. Pnls 1AD11& 12, Inv.

A-B52 Control Bldg Lvi B

  • 1AD11l, BCs 1AD1CA & 1CB. MCC 1AD1 M, and i 120 VAC Pnl1AY1A 125V DC Bus lBD1, Pnls 1BD11& 12.lnv I A*B47 Control Bldg LvI B 1BD112. BCs 1BD1CA & 1 MCC 1BD1 M, and 120V AC Pnl1 BY1 B 125V DC Bus 1CD1. Pnl 1CD11, Inv 1CD113, R-B55 Control Bldg Lvi B BCs lCD1CA & 1CB, 120V AC Pnl1CY1A Pnl 1DD 11, Inv 1DD 114.

I R-B48 BCs 1DD1CA & 120V AC Pnl1DY1B i R*B56 125VDC batte 1 B R-B54 125VDC bane 1AD1B R-B44 125VDC batte 1DD1B R-B49 125VDC bane lBD1B above listed rooms by ESF room coolers include all rooms that contain equipment having a safety function that are credited in the PRA for which a heat-up calculation was performed.

-13 to NL-13-1648 SNC to April 26, 2013 NRC Letter Are rooms R-B6i , Unit 1 Train 1Band the only two rooms rn""onc!:ll~nn action of opening No, the PRA model assumes action of opening doors may be for the following rooms. are the only rooms served by ESF room cooling for which heat-up evaluations determined room may reach 150 OF within 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> of of room cooling.

UNIT 1

  • Train A B52,
  • Train B B47, B48, B61 UNIT2
  • Train A B26, B29
  • Train B B18, B31, PRA model does not assume nl!:ll'ornol'lt of as a compensatory an important for SSCs modeled in the PRA; as evaluations were performed for the rooms in Table 4a-1 to determine profile during the 24 hour2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> time, assuming a total loss of room The PRA heat-up evaluations determined that room temperature remained below 150 in aU rooms, assuming to open doors to the five rooms per Unit above. Using industry references that equipment survivability and accelerated thermal aging test results, the PRA heat-up evaluation determined equipment functionality is not affected when room below 150 OF for the duration of mission time. The heat-up evaluations concluded it was not necessary to include room cooling in the PRA model either as an or a mitigating system.

Additionally, it was judged that the human error probability for failing to open the doors is small and has a negligible impact on core damage frequency and large early reU3aEie frequency.

provide guidance on taking I'nlmnOnC!:ltnnl action of opening of room cooling and include identified by the for the likelihood of a core release event.

information provided for room R-B18 on -11 well as all other rooms) the results of the room heatup calculations - for abnormal, accident, and post conditions - are that compensatory measures must implemented by 11.5 hours5.787037e-5 days <br />0.00139 hours <br />8.267196e-6 weeks <br />1.9025e-6 months <br /> into Without recovery of room cooling how must the compensatory measures be maintained?

SNC Response to NRC Question 4c PRA assumes the compensatory measure of opening room doors is rnonTt:),,, n,QTnl'O room heat-up affects initiating and mitigating for the five rooms per unit that are response. The heat-up evaluations do not compensatory action

-14 to NL-13-1648 SNC Response to April 26, 2013 NRC Letter opening doors after loss of ESF room cooling. According to the PRA heat-up evaluations, the shortest time to 150 of after loss of ESF room cooling with no operator action will occur in rooms R-B61 (Unit 1) and R-B 18 (Unit 2). These rooms are expected to heat-up to 150 of at 11.5 hours5.787037e-5 days <br />0.00139 hours <br />8.267196e-6 weeks <br />1.9025e-6 months <br /> after loss of ESF room cooling with no operator action. Additionally, industry references that describe equipment survivability and accelerated thermal aging test results establish equipment survivability for several hours at temperatures above 150 of.

Conservatively, compensatory measures must be implemented by 11.5 hours5.787037e-5 days <br />0.00139 hours <br />8.267196e-6 weeks <br />1.9025e-6 months <br /> after loss of ESF room cooling for rooms R-B61 (Unit 1) and R-B18 (Unit 2). Rooms R-B47, R-B52, R B55, and R-B48 (Unit 1) and R-B26, R-B29, R-B31, and R-B36 (Unit 2) reach 150 of at times longer than 11.5 hours5.787037e-5 days <br />0.00139 hours <br />8.267196e-6 weeks <br />1.9025e-6 months <br /> after loss of ESF room cooling without implementation of compensatory actions of opening doors. For all other rooms, the VEGP PRA heat-up evaluations concluded that the room temperature remained below 150 of during the 24 hour2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> PRA mission time after loss of ESF room cooler with no operator action.

The VEGP PRA assumes that the compensatory measure of opening doors for the five rooms per Unit listed above will be maintained until PRA success criteria are met or until the action is no longer needed (e.g. due to recovery of ESF chiller and room coolers).

NRC Question 5 No Significant Hazards Consideration Determination (NSHC)

The FSAR 9.2.9.1.1.1, Safety Design Basis C, discusses the loss of ESF switchgear and the emergency safeguard feature pumps. Please discuss any change in the probability of a loss of function for these components due to the proposed CT extension and its impact on the NSHC determination.

SNC Response to NRC Question 5 During normal plant operation, both trains of the essential chilled water system are on standby, as the power plant cooling is provided by the normal chilled water system. On a safety injection signal, or control room isolation Signal, both trains of the essential chilled water system are automatically actuated; however, on loss of offsite power the essential chilled water system is manually actuated.

The Unit's operable emergency chilled water system (ECWS) is a separate independent train that provides the required cooling to the redundant loads in the operable ECWS train and all of the equipment served by the operable ECWS train will provide the required cooling.

Disregarding other unrelated failures, the redundant train loads will be operable and capable of performing their intended function. Should LCO 3.7.14 Condition A be entered, the remaining train's ESF room coolers and ECWS will be designated as a "Protected Train" within 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br />, and until the time that Condition A is exited. Page E1-14 of the SNC LAR describes actions required once a train is deSignated as protected. As stated in the response to Question 3a, the remaining compensatory actions listed in Enclosure 4 to the SNC LAR will also be implemented within 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br /> of entering Condition A, through the time that Condition A is exited. The compensatory actions will increase the likelihood that the ESF systems will respond as required following a DBA, even without its associated ESF room cooler and chiller system being operable. Per LCO 3.0.6, if a loss of safety function of the supported equipment is determined to exist by the Safety Function Determination Program (SFDP) (Specification 5.5.15), the appropriate Conditions and Required Actions of the LCO in which the loss of safety function exists are required to be entered. If the remaining operable ECWS train were to become inoperable, LCO 3.0.3 would be entered. Accordingly, there is no significant reduction in margin E1-15 to NL-1 648 SNC Response to April 3NRC of safety. The probability of an previously evaluated and the probability of a new or different kind of accident from any previously evaluated are unaffected by this change.

NRC Question 6 Technical Specifications The LAR would increase the Time for TS 3.7.14 Condition A from hours to 7 days or 14 days for chiller overhaul maintenance. Page E1-3 of the LAR request ~t'!:li,o~'

This proposed change to is similar to the previous 2A essential chiller TS revision for chiller to be inoperable for 14 days to into the refrigerant to chiller hermetic compressor motor NL-10-1609 NL-10-1 18, 2010), for which Operating Company (SNC) re£""I approval on August 1 Page E1-7 of the amendment that the chiller overhaul planned maintenance activities require substantially more time than currently allowed by TS 3.7.14 and such work is typically performed during refueling outages. It is further stated that the work is scheduled to be performed while online.

On December 19. 2011, the submitted an amendment request for a similar change (ADAMS Accession No. ML113550489). -6 of the December 2011 amendment states that a chiller overhaul was originally scheduled for September 18, 2011 with a March 11, 2013 and that the overhaul was deferred from the fall 2011 outage. Page 2 of the December 2011 amendment cover letter states that a refueling outage is to start on March 10,2013.

Page B 3.0-2 of Vogtle Units 1 and 2 The Completion Actions are also applicable when a system or component is from intentionally. The reasons for intentionally the ACTIONS include, but are limited to, performance of Surveillances, maintenance, rnrr""r""/Q or of operational problems.

ACTIONS for reasons in a manner that does not compromise safety. Intentional entry not be made for operational convenience.

Alternatives that would not in redundant equipment being inoperable should used instead.

NRC Question 6a Given that the August 2010 amendment was necessary to preclude an unplanned shutdown and that the chiller overhaul was in fall 2011 outage and that a refueling outage is scheduled to start on March 10, it is not apparent to the staff that the operational conditions at the plant in 2010 are to conditions at this time. Please state why the current operational conditions justify amendment.

SNC Response to NRC Question 6a SNC is no longer pursuing 14-day time for the chiller overhaul maintenance activities. The current 72-hour completion time for Condition A has resulted in SNC either having to seek or being to regulatory relief due to the insufficient

-16

1 to NL-1 648 SNC Response to April 26, 2013 NRC Letter 72-hour time to complete needed maintenance on several occasions. Allowing a 7-day completion time will allow for more thorough troubleshooting techniques and for resolution to prepare and perform maintenance and functional testing.

NRC Question 6b Please demonstrate how the alternative to intentionally entering Condition A, that is, overhauling the during outage, is not PO~3SI[)le.

SNC Response to NRC Question 6b SNC is no longer pursuing the 14 completion time for overhaul maintenance.

-17

Vogtle Electric Generating Plant Response to Supplemental Information Needed for Acceptance of License Amendment Request for Technical Specification 3.7.14 Completion Time Enclosure 2 Revised Marked-Up Technical Specification and Bases Pages

Room Cooler Safety-Related Chiller System 3.7.14 PLANT 3.7.14 Engineered Safety Features Room Cooler and Related Chiller System 3.7.14 Two ESF Room and Cl''' Chiller shall be One may be from service

5 2 hours2.314815e-5 days <br />5.555556e-4 hours <br />3.306878e-6 weeks <br />7.61e-7 months <br /> administrative controls for surveillance testing of the other Safety-Related Chiller train.

APPLICABILITY: MODES 1, 2, 3, and 4.

CONDITION ACTION One ESF room cooler Restore room and chiller cooler and safety-related train inoperable. chiller train to OPERABLE Required Action in MODE 3. 6 hours6.944444e-5 days <br />0.00167 hours <br />9.920635e-6 weeks <br />2.283e-6 months <br /> Completion not met.

Be in MODE 5. hours

"'For the VEGP Unit 2 August 16, 2010 entry into Technical Specifications 3.7.14 Condition A, one ESF roem Geeler and safety related chiller train may be inoperable fer a period not to exceed 14 days.

Vogtle 1 and 2 3.7.14-1 Amendment No. W (Unit 1)

Amendment 4J.9 (Unit

Room Cooler and Safety-Related Chiller System B3.7.14 BASES LCO b. The associated chilled water system, including the chiller, (continued) water pump, piping, valves, and instrumentation required to perform safety-related function is The LCO is modified by a Note that allows one safety-related chiller train to removed from service for up to 2 hours2.314815e-5 days <br />5.555556e-4 hours <br />3.306878e-6 weeks <br />7.61e-7 months <br /> under administrative controls for surveillance testing of the other chiller train. This note is required to allow surveillance testing to be performed separately on each safety-related chiller train. Such testing may include individual automatic starts of chiller train. Administrative controls must be in place to ensure the train removed from can be rapidly returned to service if the need When this note is utilized, the train from is not required OPERABLE during the other APPLICABILITY In MODES 1, 2, 3, and room cooler and safety-related chiller system must be OP to provide a safety-related cooling function consistent with the OPERABILITY reqUirements of the ESF equipment it supports. In MODES 5 or 6, there are no OPERABILITY requirements for the room cooler and safety-related chiller system. However, the functional requirements of the ESF room cooler and safety-related chiller system to provide supplemental cooling for normal HVAC are determined by the systems it supports. In MODES, any supplemental cooling provided by the ESF room cooler and safety-related chiller system is not a required safety function the system.

ACTIONS If one ESF room cooler and safety-related chiller inoperab Ie, action must :'ita~k~e~n~~~nrITici~rfffi~fu,e1 OPERABLE status within + '------=--'

remaining OPERABLE room train is adequate to perform the its associated equipment.

However, the overall reliability is reduced because a single failure in the OPERABLE room cooler and safety-related chiller system train could result in loss of the ESF room ~7-day safety-related chiller system function. 72 he ompletion Time is based on the redundant capabilities afforded by the train, and the low probability of a DBA occurring during this time.

Vogtle Units 1 and 2 B 3.7.1

Iinsert 1 Within 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br /> of entering Condition A, the Configuration Risk Management Program (CRMP) shall be implemented. The CRMP is used to assess changes in core damage frequency resulting from applicable plant configurations. The CRMP uses the equipment out of service risk monitor, a computer based tool that may be used to aid in the risk assessment of on-line maintenance and to evaluate the change in risk from a component failure. The equipment out of service risk monitor uses the plant probabilistic risk assessment model to evaluate the risk of removing equipment from service based on current plant configuration and equipment condition.

Vogtle Electric Generating Plant HeSlJc:m!~e to Supplemental Information Needed for Acceptance Amendment Request for Technical Specification 3.7.14 Completion Time Enclosure 3 Clean Typed Technical Specification Page

ESF Room Cooler and Safety-Related Chiller System 3.7.14 3.7 PLANT SYSTEMS 3.7.14 Engineered Safety Features (ESF) Room Cooler and Safety Related Chiller System LCO 3.7.14 Two ESF Room Cooler and Safety-Related Chiller trains shall be OPERABLE.

NOTE----------------------------------------------

One Safety-Related Chiller train may be removed from service for S 2 hours2.314815e-5 days <br />5.555556e-4 hours <br />3.306878e-6 weeks <br />7.61e-7 months <br /> under administrative controls for surveillance testing of the other Safety-Related Chiller train.

APPLICABILITY: MODES 1,2,3, and 4.

ACTIONS CONDITION REQUIRED ACTION COMPLETION TIME A. One ESF room cooler A.1 Restore the ESF room 7 days and safety-related chiller cooler and safety-related train inoperable. chiller train to OPERABLE status.

B. Required Action and B.1 Be in MODE 3. 6 hours6.944444e-5 days <br />0.00167 hours <br />9.920635e-6 weeks <br />2.283e-6 months <br /> Associated Completion Time not met. AND B.2 Be in MODE 5. 36 hours4.166667e-4 days <br />0.01 hours <br />5.952381e-5 weeks <br />1.3698e-5 months <br /> Vogtle Units 1 and 2 3.7.14-1 Amendment No. (Unit 1)

Amendment No. (Unit 2)

Vogtle Electric Generating Plant Response to Supplemental Information Needed for Acceptance of License Amendment for Specification 3.7.14 Completion Enclosure 4 Commitment Table

Enclosure 4 to NL-13-1648 Commitment Table list of Regulatory Commitments The following table identifies the regulatory commitments in this document. Any other statements in this submittal represent intended or planned actions. Such statements are provided for information purposes and are not considered to be regulatory commitments.

Regulatory Commitments Event Duration The remaining train ESF Room Cooler and Safety-Related Chiller System will be operated as a Within 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br /> of entering Condition A Protected Train per procedure NMP-OS-010.

The Unit 1 low voltage switchyards and the Unit 2 low voltage switchyards will be maintained available (that Within 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br /> of entering Condition A is, no routine testing or maintenance activities will be performed).

High voltage switchyards will be maintained available (that is, no routine testing or maintenance activities will be performed) with the exception of work activities Within 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br /> of entering Condition A which do not challenge both feeders from offsite power sources will be permitted and managed as a high Operational Risk Awareness job.

The Unit 1 and Unit 2 Train A and Train 8 Emergency Diesel Generators will be maintained available (that is, Within 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br /> of entering Condition A no routine testing or maintenance activities will be performed).

The Normal Chilled Water System will be maintained available (that is, no routine testing or maintenance Within 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br /> of entering Condition A activities will be performed).

The opposite Unit's Essential Chilled Water System and the opposite Unit's CREFS will be maintained available to support control room cooling (that is, no Within 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br /> of entering Condition A routine testing or maintenance activities will be performed).

Equipment room doors will be propped open for safety related 125VDC and 120VAC equipment rooms on the Within 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br /> of entering Condition A affected train.

E4-1

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