W3F1-2022-0059, Response to Clarification Questions Concerning Supplement to License Amendment Request to Adopt TSTF-505

Response to Clarification Questions Concerning Supplement to License Amendment Request to Adopt TSTF-505

ML22286A239
Person / Time
Site:	Waterford
Issue date:	10/13/2022
From:	Couture P Entergy Operations
To:	Document Control Desk, Office of Nuclear Reactor Regulation
References
W3F1-2022-0059
Download: ML22286A239 (10)

Text

Phil Couture Senior Manager Fleet Regulatory Assurance - Licensing 601-368-5102 W3F1-2022-0059 10 CFR 50.90 October 13, 2022 ATTN: Document Control Desk U.S. Nuclear Regulatory Commission Washington, DC 20555-0001

Subject:

Response to Clarification Questions Concerning Supplement to License Amendment Request to Adopt TSTF-505 Waterford Steam Electric Station, Unit 3 NRC Docket No. 50-382 Renewed Facility Operating License No. NPF-38 By letter dated February 8, 2021 (Reference 1), as supplemented by letters dated April 8, 2021 (Reference 2), May 16, 2022 (Reference 3), and August 19, 2022 (Reference 4), Entergy Operations, Inc. (Entergy) submitted a license amendment request (LAR) to permit the use of risk-informed completion times (RICTs) consistent with the methodologies presented in Technical Specification Task Force (TSTF) Traveler TSTF-505, Revision 2, "Provide Risk-Informed Extended Completion Times - Initiative 4b," and Nuclear Energy Institute (NEI) 06-09, Revision 0-A, "Risk-Informed Technical Specifications Initiative 4b: Risk-Managed Technical Specifications (RMTS) Guidelines."

On August 30, 2022, Entergy received a set of five questions via electronic mail (email) from the Nuclear Regulatory Commission (NRC) Electrical Engineering Branch (EEEB) and a request for a clarification call to discuss the questions. The questions were prepared by the EEEB to clarify concerns regarding the May 16, 2022 supplement to the TSTF-505 LAR. A conference call was subsequently held with the NRC EEEB on September 19 to provide the requested clarification.

Following the clarification call, the NRC and Entergy agreed to docket the responses to questions 2, 3, and 5. This submittal provides those responses.

The Enclosure of this letter provides a restatement of the three NRC EEEB questions followed by Entergy's responses. The Attachment to the Enclosure provides the changes to Table E.1-1; the complete table was previously provided in Reference 3. There were no changes to the table other than those indicated in the Attachment.

Entergy has reviewed the information supporting the No Significant Hazards Considerations and the Environmental Evaluations that were previously provided to the NRC in the Enclosure of the Reference 1 LAR. The information in this submittal does not alter the previous conclusions that Entergy Operations, Inc., 1340 Echelon Parkway, Jackson, MS 39213

W3F1-2022-0059 Page 2 of 3 the proposed changes present no significant hazards consideration and no environmental impact statement or environmental assessment need be prepared in connection with the proposed amendments.

This letter contains no new regulatory commitments.

In accordance with 10 CFR 50.91(b)(1), "Notice for public comment; State consultation," a copy of this letter is being provided to the designated State Official.

Should you have any questions or require additional information, please contact Leia Milster, Regulatory Assurance Manager, Waterford 3, at 504-739-6250.

I declare under penalty of perjury, that the foregoing is true and correct. Executed on October 13, 2022.

Respectfully, Philip Digitally signed by Philip Couture Couture Date: 2022.10.13 16:10:00 -05'00' Phil Couture PC/cdm

Enclosure:

Response to NRC EEEB Questions 2, 3, and 5 Attachment to Enclosure - Proposed Changes to Table E.1-1

References:

1) Entergy letter to NRC, "Application for Technical Specification Change to Adopt Risk-Informed Extended Completion Times - RITSTF Initiative 4B," (ADAMS Accession No. ML21039A648), dated February 8, 2021

2) Entergy letter to NRC, "Supplement to Application for Technical Specifications Change to Adopt Risk-Informed Extended Completion Times - RITSTF Initiative 4b," (ADAMS Accession No. ML21098A262),

dated April 8, 2021

W3F1-2022-0059 Page 3 of 3

3) Entergy letter to NRC, "Response to Request for Additional Information to License Amendment Request to Revise Technical Specifications to Adopt TSTF-505, Revision 2, 'Provide Risk Informed Extended Completion Times - RITSTF Initiative 4b,'" (ADAMS Accession No. ML22136A310),

dated May 16, 2022

4) Entergy letter to NRC, Response to Request for Additional Information Regarding License Amendment Requests to Adopt 10 CFR 50.69 and TSTF-505, (ADAMS Accession No. ML22231B160), dated August 19, 2022 cc: NRC Region IV Regional Administrator NRC Senior Resident Inspector - Waterford Steam Electric Station, Unit 3 NRC Project Manager Waterford Steam Electric Station, Unit 3 Louisiana Department of Environmental Quality

Enclosure W3F1-2022-0059 Response to NRC EEEB Questions 2, 3, and 5

W3F1-2022-0059 Enclosure Page 1 of 3 RESPONSE TO NRC EEEB QUESTIONS 2, 3, AND 5 By letter dated February 8, 2021 (Reference 1), as supplemented by letters dated April 8, 2021 (Reference 2), May 16, 2022 (Reference 3), and August 19, 2022 (Reference 4), Entergy Operations, Inc. (Entergy) submitted a license amendment request (LAR) to permit the use of risk-informed completion times (RICTs) consistent with the methodologies presented in Technical Specification Task Force (TSTF) Traveler TSTF-505, Revision 2, "Provide Risk-Informed Extended Completion Times - Initiative 4b," and Nuclear Energy Institute (NEI) 06-09, Revision 0-A, "Risk-Informed Technical Specifications Initiative 4b: Risk-Managed Technical Specifications (RMTS) Guidelines."

On August 30, 2022, Entergy received a set of five questions via electronic mail (email) from the Nuclear Regulatory Commission (NRC) Electrical Engineering Branch (EEEB) and a request for a clarification call to discuss the questions. A conference call was subsequently held with the NRC EEEB on September 19 to provide the requested clarification. Following the clarification call, the NRC and Entergy agreed to docket the responses to questions 2, 3, and 5. These questions and Entergys responses are provided below.

EEEB Question 2 UFSAR Section 8.1.3 (see UFSAR page 8.3-1) describes the transfer scheme to energize ESF buses 3AB3-S and 3AB31-S. These swing buses have dual feeder breakers from the ESF buses that supply each of them implying that only buses 3AB3-S and 3AB31-S are de-energized initially during this transfer process. The UFSAR Section 8.3.1.1.2.3 (see page 8.3-7) indicates that transfer process is a dead-bus transfer and not usually done at power. (a)

Please indicate if those swing buses are ever de-energized during Modes 1 and 2? (b) If they are always energized, is that true for their loads also (discriminate between motor and non-motor loads)? (c) Can one swing bus (3AB3-S or 3AB31-S) enter the RICT program independently of the other swing bus?

Entergy Response to EEEB Question 2(a)

The 3AB3-S 4.16 kV and 3AB31-S 480 V AB swing busses are normally energized during Modes 1, 2, 3, and 4 except during bus transfers from the Train A power supply (3A3-S 4.16 kV and 3A31-S 480 V busses) to the Train B power supply (3B3-S 4.16 kV and 3B31-S 480 V busses), or vice versa. The bus transfers are dead bus transfers performed manually and are typically short in duration. The transfer times are the time it takes to perform the bus transfers.

In direct response to the question, the AB swing busses (3AB3-S 4.16 kV and 3AB31-S 480 V) are, on occasion, deenergized during Modes 1 and 2 to support planned and emergent maintenance.

Entergy Response to EEEB Question 2(b)

The purpose of the AB swing busses is to provide extra redundant loads (a third high pressure safety injection pump, a third component cooling water pump, a third essential chiller, and associated valves) to ensure the availability of one component in each division/train during extensive maintenance. The third-of-a-kind equipment consisting of the installed spares may be utilized by connecting the 3AB3-S 4.16 kV swing bus to either the 3A3-S 4.16 kV bus or the

W3F1-2022-0059 Enclosure Page 2 of 3 3B3-S 4.16 kV bus (i.e., to the bus that has a component requiring extensive maintenance). At the same time, the 3AB31-S 480 V swing bus will be connected to the 480 V bus (3A31-S or 3B31-S) corresponding to the 4.16 kV connection. This will ensure that all related AB bus loads are always connected to the same train (division). The connection of the extra redundant loads on the 3AB3-S swing bus requires a dead bus transfer. It is, therefore, not a frequent practice to transfer the 3AB3-S and 3AB31-S swing busses when the plant is at power because the loads on the 3AB3-S bus are required to maintain Technical Specification (TS) compliance and support continued plant operation. During the infrequently performed bus transfers, the loads on the 3AB3-S and 3AB31-S swing busses are not energized.

Entergy Response to EEEB Question 2(c)

Yes. With either the 3AB3-S 4.16 kV swing bus or the 3AB31-S 480 V swing bus deenergized, entry into Waterford 3 TS Limiting Condition for Operation (LCO) 3.8.3.1 Action a would be required due to the bus not being fully energized from the train (A or B) to which it is connected.

Accordingly, the RICT program would apply to the 3AB3-S swing bus or the 3AB31-S swing bus independently when the TS LCO 3.8.3.1 Action a entry condition (bus not fully energized) is met.

EEEB Question 3 LCO 3.8.3.1 (see page 3/4 8-13) indicates that both the ESF 4.16 kV bus and the ESF 480 V bus per train must be energized. However, the design success criteria (DSC) for RA 3.8.3.1.a (see Table E1-1 of May 16th supplement) indicates that train A AC bus or train B AC bus is required with swing AB AC bus when that swing bus is powered by train A AC bus or train B AC bus when train AB AC bus loads are operational. Please verify that the DSC meets minimum required operating equipment about the number of buses (both 4kV and 480 Vac buses) required per train if LCO RA 3.8.3.1.a is entered into RICT program taking into account that each available, required remaining train must be fully energized, not partially, to perform its assigned safety functions.

Entergy Response to EEEB Question 3 The A.C. Engineered Safety Features (ESF) busses consist of the Train A 3A3-S 4.16 kV and 3A31-S 480 V busses, the Train B 3B3-S 4.16 kV and 3B31-S 480 V busses, and the Train AB 3AB3-S 4.16 kV and 3AB31-S 480 V swing busses. There are no ties between the Train A and Train B busses. The Train A and Train B busses are redundant and each train's busses can supply sufficient power to its safety related loads to enable safe shutdown, or to mitigate the consequences of a design basis accident. The Train AB swing bus loads are third-of-a-kind equipment to support unavailability of the Train A or Train B equipment. The Train AB 3AB3-S 4.16 kV swing bus is connected to either the Train A 3A3-S 4.16 kV bus or the Train B 3B3-S 4.16 kV bus, but never to both. Similarly, the Train AB 3AB31-S 480 V swing bus is tied to the same train as the 3AB3-S 4.16 kV bus at all times. The Train AB swing busses are not considered separate ESF power sources since they are powered from the Train A or the Train B busses.

TS LCO 3.8.3.1 requires the Train A, Train B, and Train AB A.C. ESF busses to be energized in Modes 1, 2, 3, and 4. Entry into TS LCO 3.8.3.1 Action a would be required if one of these

W3F1-2022-0059 Enclosure Page 3 of 3 required trains (divisions) is not fully energized due to its associated 4.16 kV and/or 480 V bus(es) being not fully energized. If the Train AB bus(es) (4.16 kV and/or 480 V) and the Train A or Train B bus(es) it is connected to are both not fully energized, then entry into TS LCO 3.8.3.1 Action a would be required. Likewise, if only the Train AB bus(es) (4.16 kV and/or 480 V) is not fully energized, entry into TS LCO 3.8.3.1 Action a would be required. Accordingly, the RICT program would apply to a Train A, Train B, and Train AB A.C. ESF 4.16 kV or 480 V bus if it is not fully energized.

It is proposed to clarify the Table E1-1 DSC for TS LCO 3.8.3.1 Action a to clarify that the Train A, Train B, and Train AB A.C. ESF busses consist of both the 4.16 kV and 480 V busses.

An excerpt from Table E1-1 that provides the revised DSC is contained in the Attachment to this Enclosure.

EEEB Question 5 Table E1-1 of Enclosure 1 of the LAR supplement dated May 16, 2022, includes descriptions of the DSC for TS to be included in the RICT program. The DSC provides the minimum remaining equipment that can achieve the TS safety function while in the specified TS Condition.

According to TS 3.8.3.1 Action cs DSC, Train DC-AB-S is required at all times. If DC-AB was declared inoperable, there would be a loss of safety function (LOF). However, a LOF condition is not allowed in the RICT program according to TSTF-505 Revision 2, please provide justification for this variation.

Entergy Response to EEEB Question 5 The Table E1-1 DSC for TS LCO 3.8.3.1 Action c included with the May 16, 2022 LAR supplement was overly restrictive, in that it unnecessarily included consideration of concurrent failures. Currently, in accordance with TS LCO 3.8.3.1 Action c, with the 3AB-DC-S 125-volt D.C. bus inoperable due to not being energized, which includes a condition involving its associated battery bank (3AB-S) not being connected, the D.C. bus is required to be reconnected from its associated Operable battery bank within 2 hours2.314815e-5 days <br />5.555556e-4 hours <br />3.306878e-6 weeks <br />7.61e-7 months <br /> or be in at least Hot Standby within the next 6 hours6.944444e-5 days <br />0.00167 hours <br />9.920635e-6 weeks <br />2.283e-6 months <br /> and in Cold Shutdown within the following 30 hours3.472222e-4 days <br />0.00833 hours <br />4.960317e-5 weeks <br />1.1415e-5 months <br />. During this period (i.e., while in Action c), the other two 125-volt DC safety busses (3A-DC-S and 3B-DC-S) along with the AC safety busses would remain available. Therefore, entry into TS LCO 3.8.3.1 Action c would have no effect on the capability of the A and B D.C. busses or their associated A.C. power sources to perform their specified TS functions. Accordingly, TS LCO 3.8.3.1 Action c is within the scope of the RICT program in accordance with TSTF-505, Revision 2.

It is proposed to revise the Table E1-1 DSC for TS LCO 3.8.3.1 Action c to clarify the status of the 125-volt D.C. ESF busses and associated battery banks (batteries) needed to ensure power is provided to the 125-volt D.C. busses for operability, consistent with the TS LCO 3.8.3.1 specified function. The changes to the DSC also include the correction of an editorial error in the written designation of the 3AB-S Battery. An excerpt from Table E1-1 that provides the revised DSC is contained in the Attachment to this Enclosure.

Enclosure, Attachment W3F1-2022-0059 Changes to Table E1-1

W3F1-2022-0059 Enclosure, Attachment Page 1 of 2 Changes to Table E1-1 (Note: Changes are in BOLD and Underlined)

Table E1-1 Proposed TS LCO and SSCs Covered SSC in Functions Covered Design Success PRA Success Criteria Disposition Proposed Actions by TS LCO PRA by TS LCO Action Criteria Action Model 3.8.3.1 Onsite Power Distribution Systems.

The following Engineered Safety Features (ESF) and Static Uninterruptible Power Supply (SUPS) busses shall be energized in the specified manner. The tie breakers from the Train AB Busses shall be connected to either Train A or Train B.

See TS 3.8.3.1 list of onsite A.C. and D.C.

busses required to be energized.

Action 3.8.3.1 a A.C. Busses. Yes Engineered Safety Train A A.C. 4.16 kV and Same as Design SSCs are modeled With one of the required Features (ESF) and 480 V busses energized Success Criteria. consistent with the TS divisions of A.C. ESF Static Uninterruptible or Train B A.C. 4.16 kV scope and so can be busses not fully Power Supply and 480 V busses evaluated using the energized, reenergize (SUPS) busses shall energized and supplying CRMP tool. The success the division within 8 be energized in the safety related criteria in the PRA are hours specified manner: equipment. consistent with the design basis success criteria.

a. Train A A.C. AND Busses.

Train AB A.C. 4.16 kV

b. Train B A.C. and 480 V busses Busses. powered from Train A A.C. 4.16 kV and 480 V

c. Train AB A.C. busses or Train B A.C.

Busses. 4.16 kV and 480 V busses when one or

W3F1-2022-0059 Enclosure, Attachment Page 2 of 2 Table E1-1 Proposed TS LCO and SSCs Covered SSC in Functions Covered Design Success PRA Success Criteria Disposition Proposed Actions by TS LCO PRA by TS LCO Action Criteria Action Model more AB swing components are being utilized to replace Train A or B safety related components.

Action 3.8.3.1 c Three 125-volt Yes Power to 125-volt 3A-DC-S bus energized Same as Design SSCs are modeled With one D.C. bus not D.C. Busses D.C. Busses. and connected to 3A-S Success Criteria. consistent with the TS connected to its and associated Battery, and 3AB-DC-S scope and so can be associated battery bank, Battery Banks: bus energized and evaluated using the reconnect the D.C. bus connected to 3AB-S CRMP tool. The success from its associated 1. Bus 3A-DC- Battery. criteria in the PRA are OPERABLE battery S and 3A-S consistent with the design bank within 2 hours2.314815e-5 days <br />5.555556e-4 hours <br />3.306878e-6 weeks <br />7.61e-7 months <br /> Battery. OR basis success criteria.

2. Bus 3B-DC- 3B-DC-S bus energized S and 3B-S and connected to 3B-S Battery. Battery, and 3AB-DC-S bus energized and

3. Bus 3AB- connected to 3AB-S DC-S and Battery.

3AB-S Battery. OR 3A-DC-S bus energized and connected to 3A-S Battery, and 3B-DC-S bus energized and connected to 3B-S Battery.