RA-18-0023, License Amendment Request (2017-05) to Add a Surveillance Requirement to Technical Specification 3.8.1, AC Sources

License Amendment Request (2017-05) to Add a Surveillance Requirement to Technical Specification 3.8.1, AC Sources

ML18144A788
Person / Time
Site:	Oconee
Issue date:	05/17/2018
From:	Burchfield J Duke Energy Carolinas
To:	Document Control Desk, Office of Nuclear Reactor Regulation
References
RA-18-0023
Download: ML18144A788 (26)

Text

(_~ DUKE ENERGY J. Ed Burchfield, Jr.

Vice President Oconee Nuclear Station Duke Energy ON01 VP I 7800 Rochester Hwy Seneca, SC 29672 o: 864 .873.3478 f 864.873.5791 Ed.Burchfield@duke-energy.com RA-18-0023 10 CFR 50.90 May 17, 2018 ATTN : Document Control Desk U.S. Nuclear Regulatory Commission Washington , DC 20555-0001

• Duke Energy Carolinas, LLC Oconee Nuclear Station (ONS), Units 1, 2, and 3 Docket Numbers 50-269, 50-270, and 50-287 Renewed Facility Operating License Nos. DPR-38, DPR-47, and DPR-55

Subject:

License Amendment Request to Add a Surveillance Requirement to Technical Specification 3.8.1, AC Sources - Operating License Amendment Request No. 2017-05 Pursuant to 10 CFR 50.90, Duke Energy Carolinas, LLC (Duke Energy) proposes to amend Renewed Facility Operating License Nos. DPR-38, DPR-47, and DPR-55 for Oconee Nuclear Station (ONS) Units 1, 2, and 3. The License Amendment Request {LAR) proposes to add a Surveillance Requirement to Technical Specification {TS) 3.8.1, AC Sources - Operating , to require verifying the ability of each Keowee Hydroelectric Unit (KHU) auxiliary power system to automatically transfer from its normal auxiliary power source to its alternate auxiliary power source.

The Enclosure to this letter provides an evaluation of the proposed TS change. A regulatory evaluation (including the Significant Hazards Consideration Determination Analysis) and Environmental Considerations are provided in Sections 4 and 5 of the Enclosure. Attachments 1 and 2 provide marked-up TS and TS Bases pages, respectively. Attachment 3 provides retyped (clean) TS pages . Attachment 4 provides marked-up Updated Final Safety Analysis Report (UFSAR) pages. The marked-up TS Bases and UFSAR pages are provided for information only.

In accordance with Duke Energy administrative procedures that implement the Quality Assurance Program Topical Report, these proposed changes have been reviewed and approved by the Operations Review Committee. A copy of this LAR is being sent to the State of South Carolina in accordance with 10 CFR 50.91 requirements.

Duke Energy requests approval of the proposed LAR by May 17, 2019, effective immediately upon issuance with implementation within 60 days. Duke Energy will also upqate applicable sections of the ONS UFSAR, as necessary, and submit these per 10 CFR 50.71(e). There are no regulatory commitments being made as a result of the proposed change.

U. S. Nuclear Regulatory Commission May 17, 2018 Page 2 Inquiries on this proposed amendment request should be directed to Boyd Shingleton, ONS Regulatory Affairs Group, at (864) 873-4716.

I declare under penalty of perjury that the foregoing is true and correct. Executed on May 17, 2018.

Sincerely, JCJ~

J. Ed Burchfield , Jr.

Vice President Oconee Nuclear Station

Enclosure:

Evaluation of Proposed Change Attachments:

1 Marked-Up Technical Specifications Page 2 Marked-Up Technical Specification Bases Pages 3 Retyped Technical Specifications Page 4 Marked-Up UFSAR Pages

U. S. Nuclear Regulatory Commission May 17, 2018 Page 3 cc w/enclosure and attachments:

Ms. Catherine Haney, Administrator, Region II U.S. Nuclear Regulatory Commission Marquis One Tower 245 Peachtree Center Ave ., NE, Suite 1200 Atlanta, GA 30303-1257 Ms. Audrey Klett, Project Manager (by electronic mail only)

Office of Nuclear Reactor Regulation U.S. Nuclear Regulatory Commission Mail Stop 0-8G9A 11555 Rockville Pike Rockville , Maryland 20852 Mr. Eddy Crowe NRC Senior Resident Inspector Oconee Nuclear Station Ms. Susan E. Jenkins, Manager,

{by electronic mail only: jenkinse@dhec.sc.qov)

Infectious and Radioactive Waste Management, Bureau of Land and Waste Management Department of Health & Environmental Control 2600 Bull Street Columbia, SC 29201

ENCLOSURE EVALUATION OF PROPOSED CHANGE LICENSE AMENDMENT REQUEST 2017-05

Subject:

License Amendment Request to Add a Surveillance Requirement to Technical Specification 3.8.1, AC Sources - Operating 1

SUMMARY

DESCRIPTION 2 DETAILED DESCRIPTION 2.1. AC Power System 2.2. Keowee Auxiliary Power Transfer Function 2.3. Reason for Change 2.4. Description of Proposed Change 3 TECHNICAL EVALUATION 4 REGULATORY EVALUATION 4.1. ' Applicable Regulatory Requirements/Criteria 4.2. . Significant Hazards Consideration 4.3. Conclusions 5 ENVIRONMENTAL CONSIDERATION 6 REFERENCES

License Amendment Request No. 2017-05 Enclosure May 17, 2018 Page 1 1 Summary Description The License Amendment Request (LAR) proposes to add a Surveillance Requirement to Technical Specification (TS) 3.8.1, AC Sources - Operating , to require verifying the ability of each Keowee Hydroelectric Unit (KHU) auxiliary power system to automatically transfer from its normal auxiliary power source to its alternate auxiliary power source.

This Enclosure provides an evaluation of the proposed TS change . A regulatory evaluation (including the Significant Hazards Consideration Determination Analysis) and Environmental Considerations are provided in Sections 4 and 5 of the Enclosure. Attachments 1 and 2 provide marked-up TS and TS Bases pages, respectively. Attachment 3 provides retyped (clean) TS pages. Attachment 4 provides marked-up Updated Final Safety Analysis Report (UFSAR) pages. The marked-up TS Bases and UFSAR pages are provided for information only.

2 Detailed Description 2.1 AC Power System The Oconee Nuclear Station (ONS) AC Power System consists of the offsite power sources (preferred power) and the onsite standby power sources, Keowee Hydro Units (KHUs). Refer to Figure 2 at the end of Section 2. This system is designed to supply the required Engineered Safeguards (ES) loads of one unit and safe shutdown loads of the other two units and is so arranged that no single failure can disable enough loads to jeopardize plant safety. The design of the AC Power System provides independence and redundancy to ensure an available source of power to the ES systems .

The Keowee Hydro Station contains two units rated 87,500 kVA each of which generate at 13.8 kV. The KHU turbine generators are powered through a common intake (penstock) by water taken from Lake Keowee . Upon loss of power from the Oconee generating unit and 230 kV switchyard , power is supplied from both KHUs through two separate and independent routes . The underground emergency power path is from one KHU through the underground feeder circuit, transformer CT-4, the CT-4 incoming breakers (SK breakers), standby bus and the standby breakers (S breakers). The overhead emergency power path is from the other KHU through the startup transformer and the startup incoming breakers (E breakers ).

The standby buses can also receive power from either one of two combustion turbine generators at the Lee Steam Station through a dedicated 100 kV transmission line, transformer CT-5, and both CT-5 incoming breakers (SL breakers). The 100 kV transmission line can be supplied from a Lee combustion turbine (LCT) and electrically separated from the system grid and offsite loads. The limiting capacity available from any of the multiple sources of AC power is 22.4 MVA (lim ited by either CT-4 or CT-5 transformer capacities) .

The Oconee Nuclear Station (ONS) current licensing basis (CLB) includes allowances for using Keowee Hydro Units (KHUs) for commercial generation in addition to their Technical Specification (TS) 3.8.1 required function of onsite emergency power sources . TS 3.8.1 and Selected Licensee Commitment (SLC) 16.8.4, Keowee Operational Restrictions , include requirements for certain features and operational restrictions to ensure that KHUs can transition from commercial operation mode to onsite emergency power mode and meet all accident

License Amendment Request No. 2017-05 Enclosure May 17, 2018 Page 2 analysis assumptions . One such feature is the Zone Overlap Protection Circuitry (TS LCO 3.8.1.c).

This circuitry was designed and licensed to mitigate electrical faults in the zone overlap region (References 1 and 2). During KHU generation using the KHU assigned to the underground path , an electrical fault in the zone overlap region initially results in the lockout of the KHU aligned to the underground emergency power path from both underground and the overhead emergency power paths. In addition, the KHU that was aligned to the overhead emergency power path, is not electrically connected to the remaining operable emergency power path (the underground power path). The Zone Overlap Protection Circuitry detects this and autoniatically re-aligns the operable KHU to the operable power path . As an example (refer to Figure 1 below), assume KHU-1 is the underground KHU and KHU-2 is the overhead KHU , KHU-1 itself is locked out (ACB-1 and ACB-3 are opened) and PCB-8, PCB-9, and ACB-2 are opened to lock out the overhead power path. The Zone Overlap Protection Circuitry, upon detection of these conditions , closes ACB-4 to connect KHU-2 to the underground power path, thus ensuring an emergency power source to ONS. Likewise, if KHU-2 is the underground KHU and KHU-1 is the overhead KHU , KHU-2 itself is locked out (ACB-2 and 4 are opened) and PCB-8, PCB-9, and ACB-1 are opened to lock out the overhead power path. The Zone Overlap Protection Circuitry would then close ACB-3 to connect KHU-1 to the underground path.

Figure 1 KEOWEE ELECTRICAL DISTRIBUTION To SWITCH VARO (PCB* 8 & 9)

Mai n Transformer CT- 4 CA~B CA;B CA;B CACB 2.

1X 2X Transformer Transformer KPF 9

(I KPF KP F 12 cl KPF 10

• 11 CT-6 From 1TC CT-7 PSW PSW ex ~

T CAC B ( IACB ( IACB CACB I 5 I 7 I 8 I 6

( 1X LOAD CENTER ) ( 2X LOAD CENTER )

License Amendment Request No. 2017-05 Enclosure May* 17, 2018 Page 3 2.2 Keowee Auxiliary Power Transfer Function The KHUs have auxiliary systems required for operation. Some are DC powered and some are AC powered. AC powered auxiliary loads are fed from Keowee load center 1X for KHU-1 and 2X for KHU-2 (refer to Figure 1). These load centers receive power from any of the following sources:

1. The Keowee Generator overhead path output through Keowee transformers 1X and 2X and ACB-5 , 6,

2. Oconee Unit 1 switchgear 1TC through Keowee transformer CX and ACB-7, 8,

3. The 230KV switchyard by back feed through the Keowee main step-up transformer, Keowee transformer 1X or 2X, and ACB-5 or 6.

The normal alignments for the Keowee auxiliaries are:

1. The unit aligned to the overhead will receive normal power as stated in #1 or #3 above.

2. The unit aligned to the underground will receive normal power as stated in #2 above.

3. The incoming ACB normally closed for each unit (ACB-5 or 6 for the overhead unit, ACB-7 or 8 for the underground unit) is referred to as the normal breaker, and the associated source is called the normal source.

4. . The other ACB and source for each unit is referred to as the alternate breaker and source.

The KHU aligned to the underground power path is required to have its auxiliaries aligned to receive power from Keowee transformer CX and the KHU aligned to the overhead power path is required to have its auxiliaries aligned to receive power from its auxiliary transformer (Keowee transformers 1X and 2X for KHU-1 and KHU-2, respectively). This is to ensure independence of auxiliary power sources for the two KHUs to preclude the possibility of a single failure causing a loss or lockout of auxiliary power to both Keowee units.

Each normal and alternate breaker has its own undervoltage relay and manual control switch .

One auto-manual switch per load center is provided to allow changeover froni "Auto" to "Man" control. With the selector switch in "Auto," the logic is designed such that if normal power is lost and alternate power is available, the incoming breakers will transfer automatically to the alternate source.

License Amendment Request No. 2017-05 Enclosure May 17, 2018 Page 4 2.3 Reason for the Proposed Change The proposed change will allow ONS to credit the Keowee auxiliary power automatic transfer feature (in place of the currently credited manual operator actions) during a postulated electrical fault mitigated by the Zone Overlap Protection Circuitry when the underground assigned KHU is generating to the grid. The electrical fault results in lockout of both the underground KHU and overhead power path. As a result, Keowee transformers 1X and 2X are de-energized and the only remaining source of AC auxiliary power for Keowee is transformer CX. While the Zone Overlap Protection Circuitry ensures the generator of the overhead KHU is realigned to the underground power path, the circuitry does not realign auxiliary power for the KHU to transformer CX. While a KHU can start and operate for some amount of time without AC power to auxiliary loads, this power must be recovered in order to ensure continued operability of the KHU. The most limiting auxiliary load in terms of timing to restore AC auxiliary power is the governor oil system . A recent review initiated by Duke Energy determined that for events where a KHU is initially in commercial generation mode, following an emergency start signal, the governor oil accumulators would be exhausted and governor oil pumps would be required to start within a few minutes. More time is available if the KHU is initially in standby, as less wicket g.ate movement is required to bring a KHU to rated speed from standby compared with recovering from load rejection that occurs on receipt of an emergency start signal if operating for commercial generation .

In most single-failure scenarios, regardless of the initial status of the KHU (i.e., standby or operating for commercial generation) the emergency power path assignment of KHUs does not change following receipt of emergency start signal. Following the initial loss of offsite power (LOOP) and emergency start signal, the underground KHU will regain power to its AC auxiliary loads once 1TC switchgear is reenergized and the overhead KHU will regain power to its AC auxiliary loads once its overhead tie breaker (ACB-1 or ACB-2) closes to energize the overhead power path . This is designed and tested to occur in less than 33 seconds.

As previously described, automatic circuitry does exist within load centers 1X and 2X to automatically realign the load center from its normal source to its alternate source. The circuitry is designed to realign power upon loss of power to load center 1X and/or 2X, well within the time limitations of governor oil system capacity. While the circuitry is QA-1 and is periodically tested ,

the testing is not required by TS 3.8.1. This is discussed in letters from Duke Energy to the NRC dated May 17, 1993 (Reference 3) and December 6, 1993 (Reference 4) and a letter from NRC to Duke Energy dated September 4, 1998 (Reference 5). The NRC questioned why a TS Surveillance Requirement was not considered necessary for the auxiliary power automatic transfer logic at Keowee. Duke Energy's response was that Oconee credited manual operator action to realign auxiliary power for accident mitigation and that the automatic logic was defense in depth , was installed QA-1 , would be maintained QA-1 , and would be periodically tested. The NRC accepted this position in a September 4, 1998, Safety Evaluation (Reference 5).

Duke Energy, as a result of recent analysis reviews, determined that existing procedures and staffing requirements could challenge the ability to manually realign auxiliary power in the sho.rt timeframe necessary to support accident mitigation (i.e., within a few minutes of receipt of emergency start signal). This issue was entered into the Duke Energy corrective action program. TS 3.8.1 does not contain requirements to ensure the automatic auxiliary power transfer logic is operable to support Keowee operability. As such , this is considered a non-

License Amendment Request No. 2017-05 Enclosure May17,2018 Page 5 conservative Technical Specification. Immediate action taken was to restrict the underground assigned KHU from commercial generation to meet the guidance in NRC Administrative Letter 98-10, "Dispositioning of Technical Specifications that are Insufficient to Assure Plant Safety,"

date December 29, 1998.

ONS has maintained the automatic transfer logic QA-1 and continues to periodically test the logic circuitry (currently every 18 months). Review of completed tests performed since installation of the logic circuitry confirmed that the logic on both KHUs passed all test acceptance criteria . Therefore, there is high confidence that the logic would successfully operate.

To resolve the issue, Duke Energy proposes to revise TS 3.8.1 to require testing the automatic Keowee auxiliary power transfer logic. The additional SR is required to conform to 10 CFR 50.36(c) Criterion 3.

2.4 Description of the Proposed Change Duke Energy proposes to add Surveillance Requirement (SR) 3.8.1.18 to TS 3.8.1 to require verifying the ability of a Keowee Hydroelectric Unit (KHU) *auxiliary power system to automatically transfer from its normal auxiliary power source to its alternate auxiliary power source. Once approved, Duke Energy will process a TS bases change to describe the SR and to add the automatic transfer function to the LCO Bases. A markup of the TS Bases change is included for information only in Attachment 2. The proposed TS change is as follows :

SR 3.8.1.18 Verify the ability of each KHU auxiliary power In accordance with the system to automatically transfer from its Surveillance Frequency normal auxiliary power source to its alternate Control Program auxiliary power source.

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License Amendment Request No. 2017-05 Enclosure May 17, 2018 Page 7 3 TECHNICAL EVALUATION The Keowee auxiliary power transfer function was modified in 1993 to address single failure concerns during a LOOP event. The load center (1X or 2X) in each KHU has an automatic transfer power-seeking scheme to connect it to the overhead or underground auxiliary power supply. Originally the overhead supply was the normal supply to both Keowee units and the automatic transfer logic would transfer the load centers to the underground supply if the overhead failed . Following a LOOP event in 1992 (Reference 6), ONS made a permanent change to the transfer logic that allowed the load center in the KHU aligned to the underground path to normally receive power from the underground feed (CX) and to automatically transfer to the overhead supply on its failure . Duke Energy credits operator action to ensure that power is restored to the Keowee Auxiliaries after a Design Basis event. The automatic transfer scheme was considered an enhancement (Reference 4). Regardless, the automatic transfer function is tested periodically and maintained QA-1. This testing was initially performed on a 12-month frequency but was later changed to 18 months based on operating experience and reliability verified during testing . Review of completed tests performed since installation of the logic circuitry confirmed that the logic on both KHUs passed test acceptance criteria .

The auxiliary power transfer circuitry is included in ONS's Maintenance Rule (10 CFR 50.65) monitoring program and is currently classified as A2. A review of recent maintenance history (past 3 years) found results acceptable. The following periodic maintenance and testing is performed on the equipment associated with the auxiliary power transfer circuit function:

• Doble testing of the 1X, 2X, and CX transformers .

• Inspection/testing of the auxiliary breakers (ACB-5, ACB-6 , ACB-7, and ACB-8). The breakers are functionally tested in the auxiliary power transfer surveillance test.

• Inspection/calibration of the undervoltage relays . These relays are also functionally tested in the auxiliary power transfer surveillance test.

• Functional testing and timing of time delay relays are performed during the auxiliary power transfer surveillance test.

• Functional testing of the manual control switch for each auxiliary breaker and the auto-manual control switch for each load center (1X and 2X) are performed during the auxiliary power transfer surveillance test.

Adding a TS Surveillance Requirement to require testing of the KHU auxiliary power transfer function would allow ONS to credit this automatic function to restore power to the Keowee Auxiliaries after a Design Basis Event rather than credit the manual operator action. The proposed Frequency is in accordance with the Surveillance Frequency Control Program (SFCP). The initial Frequency specified in the Surveillance Frequency List (SFL) will be 18 months based on operating experience and equipment reliability.

There are no changes being proposed to the operation of the Keowee auxiliary power system or other equipment installed at the Keowee Hydroelectric Station. The automatic power transfer feature is currently installed and in use. The equipment was installed in 1993 and is maintained QA-1. The capability to transfer power is verified by test every 18 months. If the automatic transfer does not take place, operations procedures are currently in place to restore auxiliary power manually. The only change being made is to add a TS Surveillance Requirement to

License Amendment Request No. 2017-05 Enclosure May 17, 2018 Page 8 verify the ability of either KHU auxiliary power system to automatically transfer from its normal auxiliary power source to its alternate auxiliary power source.

The proposed change will allow ONS to credit the automatic Keowee auxiliary power transfer function to support operability of the KHUs and eliminates the current crediting of manual operator action . As stated previously, the only single failure scenario mitigated by the Zone Overlap Protection Circuitry, where the automatic auxiliary power transfer logic would be required to operate, begins with the KHU assigned to the underground emergency power path commercially generating to the grid and then an electrical fault is postulated in the zone overlap region concurrent with receipt of an emergency start signal.

4 REGULATORY EVALUATION 4.1 Applicable Regulatory Requirements/Criteria The following regulatory requirements in Title 10 of the Code of Federal Regulations (10 CFR) apply to this license amendment request:

10 CFR 50.36, "Technical Specifications," which requires , in part, that a licensee establish TSs with limiting conditions for operation {LCOs) and surveillance requirements (SRs) for equipment that is required for safe operation of the facility. Specifically, Section 50.36(c) stipulates the items to be included in the TSs, including Section 50.36(c)(2), which stipulates the LCOs, and Section 50.36(c)(3), which stipulates the SRs.

10 CFR 50.63, "Loss of all alternating current power, " which requires, in part, that all nuclear power plants have the capability to withstand a loss of all alternating current (AC) power (station blackout) for an established period of time, and to recover therefrom . ONS compliance with 10 CFR 50.63 is described in Updated Final Safety Analysis Report (UFSAR) Section 8.3.2.2.4, "Station Blackout Analysis ."

The principal design criteria (PDC) for ONS were developed in consideration of the seventy General Design Criteria for Nuclear Power Plant Construction Permits proposed by the Atomic Energy Commission (AEC) in a proposed rule-making published for 10CFR Part 50 in the Federal Register on July 11 , 1967. The ONS, Units 1, 2, and 3, construction permits were issued on November 6, 1967, preceding the issuance of the GDC specified in 10 CFR 50 Appendix A. The following criteria are applicable to the proposed amendment:

ONS UFSAR, Chapter 3, Criterion 24, "Emergency Power for Protection Systems," which states that in the event of loss of all offsite power, sufficient alternate sources of power shall be provided to permit the required functioning of the Protective Systems. In the event of loss of all off-site power to all units at Oconee or to any unit alone, sufficient power for operation of the Protective Systems of any unit will be available from either of two on-site independent hydroelectric generators.

ONS UFSAR, Chapter 3, Criterion 39 , "Emergency Power for Engineered Safety Features (ESF)," which states that alternate power systems shall be provided and designed with

Li cense Amendment Request No. 2017-05 Enclosure May 17, 2018 Page 9 adequate independency, redundancy, capacity, and testability to permit the functioning required of the ESF. As a minimum , the on-site power system and the off-site power system shall each, independently, provide this capacity assuming a failure of a single active component in each power system.

4.2 Significant Hazards Consideration Determination Analysis Duke Energy Carolinas, LLC (Duke Energy) proposes to add a Surveillance Requirement to Technical Specification (TS) 3.8 .1, AC Sources - Operating to require verifying the ability of each Keowee Hydroelectric Unit (KHU) auxiliary power system to automatically transfer from its normal auxiliary power source to its alternate auxiliary power source .

Duke Energy has evaluated whether or not a significant hazards consideration is involved with the proposed amendment by focusing on the three standards set forth in 10 CFR 50.92, "Issuance of amendment," as discussed below:

1) Does the proposed amendment involve a significant increase in the probability or consequences of an accident ,previously evaluated?

No. The proposed TS change, which adds a Surveillance Requirement to TS 3.8.1 to test the automatic Keowee auxiliary power transfer circuitry, will allow ONS to credit an existing design feature to facilitate mitigation of a postulated single failure . The proposed change does not modify the reactor coolant system pressure boundary, nor make any physical changes to the facility design, material , or construction standards .

The proposed change is needed to eliminate a previously unrecognized single failure concern that resulted in a non-conservative TS . The proposed change does not affect the safety analyses thus dose consequences will remain within analyzed and acceptable limits. The probability of any design basis accident (OBA) is not increased by this change, nor are the consequences of any OBA increased by this change. The proposed change does not involve changes to any structures, systems, or components (SSCs) that can alter the probability for initiating a OBA event.

Therefore, the proposed TS change does not significantly increase the probability or consequences of an accident previously evaluated.

2) Does the proposed amendment create the possibility of a new or different kind of accident from any accident previously evaluated?

No. The proposed new Surveillance Requirement to test the automatic Keowee auxiliary power transfer circuitry will allow ONS to credit an existing design feature to facilitate mitigation of a postulated single failure . The proposed change does not alter the plant configuration (no new or different type of equipment will be installed) or make changes in methods governing normal plant operation . The automatic Keowee auxiliary power transfer circuitry is currently installed and in use but not credited for accident mitigation .

No new failure modes are identified, nor are any SSCs required to be operated outside the design bases. Therefore, the possibility of a new or different kind of accident from any kind of accident previously evaluated is not created.

License Amendment Request No. 2017-05 Enclosure May 17, 2018 Page 10

3) Does the proposed amendment involve a significant reduction in a margin of safety?

No. The proposed new Surveillance Requirement to test the automatic Keowee auxiliary power transfer circuitry will allow ONS to credit an existing design feature to facilitate mitigation of a postulated single failure. The proposed change does not involve: 1) a physical alteration of the Oconee Units; 2) the installation of new or different equipment;

3) a change to any set points for parameters which initiate protective or mitigation action; or 4) any impact on the fission product barriers or safety limits. As long as the equipment continues to perform as expected and within the guidelines captured in the safety analyses, the change does not involve a significant reduction in the margin of safety.

4.3 Conclusions In conclusion , based on the considerations discussed above, (1) there is reasonable assurance that the health and safety of the public will not be endangered by the proposed revision to TS 3.8.1 and operation of the unit in the proposed manner, (2) the proposed revision will be implemented in a manner consistent with the Commission's regulations, and (3) the issuance of the amendment will not be adverse to the common defense and security or to the health and safety of the public.

5 ENVIRONMENTAL CONSIDERATION Duke Energy Carolinas, LLC (Duke Energy) has evaluated this license amendment request against the criteria for identification of licensing and regulatory actions requiring environmental assessment in accordance with 10 CFR 51.21 . Duke Energy has determined that this license amendment request meets the criteria for a categorical exclusion as set forth in 10 CFR 51.22(c)(9). This determination is based on the fact that this change is being proposed as an amendment to a license issued pursuant to 10 CFR 50 that changes a requirement with respect to installation or use of a facility component located within the restricted area, as defined in 10 CFR 20, or that changes an inspection or a surveillance requirement, and the amendment meets the following specific criteria :

(i) The amendment involves no significant hazards consideration .

As demonstrated in Section 4.2, this proposed change to TS 3.8.1 does not involve a significant hazards consideration .

(ii) There is no significant change in the types or significant increase in the amounts of any effluent that may be released offsite.

The proposed change will not change the types or amounts of any effluents that may be released offsite.

License Amendment Request No. 2017-05 Enclosure May 17, 2018 Page 11 (iii) There is no significant increase in individual or cumulative occupational radiation exposure .

The proposed change will not increase the individual or cumulative occupational radiation exposure.

Therefore, no environmental impact statement or environmental assessment need be prepared in connection with the proposed amendment pursuant to 10 CFR 51.22(b).

6 REFERENCES

1. Letter from J . W . Hampton (Duke Power Company) to U. S. Nuclear Regulatory Commission Document Control Desk dated November 12, 1992, LER 269/92-16.

2. Letter from L. A. Wiens (NRC) to J. W . Hampton dated August 15, 1995, Issuance of Amendments - Oconee Nuclear Station , Units 1, 2, and 3.

3. Letter from J . W . Hampton (Duke Power Company) to U. S. Nuclear Regulatory Commission Document Control Desk dated May 17, 1993, Alignment of Keowee Hydro Station Auxiliary Power.

4. Letter from J. W . Hampton (Duke Power Company) to U. S. Nuclear Regulatory Commission Document Control Desk dated December 6, 1993, Response to NRC question #10 on Technical Specification 3.7 Revision .

5. Letter from D. E. LeBarge (NRC) to W . R. McCollum dated September 4, 1998, Issuance of Amendments - Oconee Nuclear Station , Units1 , 2, and 3.

6. Letter from J. W . Hampton (Duke Power Company) to U. S. Nuclear Regulatory Comm ission Document Control Desk dated November 18, 1992, LER 270/92-04.

License Amendment Request No. 2017-05 May 17, 2018 ATTACHMENT 1 MARKED-UP TECHNICAL SPECIFICATIONS PAGE

[1 page follows this cover page]

NOTE: This attachment contains marked-up TS page 3.8.1- 17.

License Amendment Request No. 2017-05 Attachment 1 May 17, 2018 AC Sources - Operating 3_,8_1 SURVEIUANCE REQUIREMENTS continued SURVEILLANCE FREQU6NCY SR 3_8_1_16 - - - - - -,,, O T E - - - - - - -

0 y applicable when complying with Required Aotion C2-2-4_

Verify one l<<iU provides an alternate manuia: As specified by Required AC :pmver souroe capability by man or Action C-2-24 automatic KHU start with manual synchronize, or breaker dosure, to ener, -ze its non-required emergency power path_

SR3_8-1 .17 Verify each 'KHU's Voltage and Frequency out In accordance - h the of tolerance logic trips and blocks closure of Surveil . oe Frequency the appropriate overhead or underground Control Program pm,ver pa breakers_ 1he allowable values with a time delay .of 5 seconds t 1 second sha be as fol 01NS:

a. Undenrottage ~ 12-42 kV and ~ 12.63 kV

b. Overvoltage ~ 14_90 kV and~ 15.18 V

c. Underfriequency ~ 53_992 hz and

~ 54JX)8 hz

d. Overlrequency ~ 65.992 hz and

~66J)08 hz r

SR 3_8-1 .18 Verify the ability of each KHU auxiliary power In accordance with the system to automatically transfer from its Surveillance Frequency normal auxiliary power source to its alternate Control Program auxiliary power source_

OCONEE UNITS 1, 2, & 3 3.BJ-17 Amendment :Nos_372, 374. 373 I

License Amendment Request No. 2017-05 May 17, 2018 ATTACHMENT 2 MARKED-UP TECHNICAL SPECIFICATION BASES PAGES

[2 pages follow this cover page]

NOTE: This attachment contains marked-up TS Bases pages B 3.8.1-2 & 26.

License Amendment Request No. 2017-05 May 17, 2018 AC Sources - O perating B 3 .8- 1 BASES BACKGRO UND receive power from a combustion turbine generator at the Lee Stearn (continued) Station 1hrough a dedicated 100 kV transm*ssion line, transfor mer CT-5, and both SL breakers. T he 100 kV transmission line can be suppl1ed from a Lee combustion turbine (LCT) and electrically separated from the system grrid and offsite loads. The minimum capacity available from any of the multiple sources of AC power is 22.4MVA {~mited by CT-4 and CT-5 transformer capacities).

APPLICABLE The initial conditions o design basis transient and a ccident ana yses SAFETY A NALYSIS in the UFSAR Chapter-6 (Re[ 4} and Oiapter 15 (Ref. 5) assum e ES systems are OPERABLE. The AC prnh'er system is designed to pm*llide sufficient capacity, capability, redundancy, and reliabifity to ensure the

• Keowee auxiliary availability of necessary prnr,i*er to ES systems so that the fuel, reactor transformer CX coolant system, and containment design limits are not exceeded.

and its alternate load center feeder Consistent with the accident analysis assum ptions of a loss of offsite breaker (ACB 7 or pmver.(LOOIP) and a singe fai ure of one onsite emergency po'll'ler path, ACB8); two onsite emergency power sources are requfred to be OPERABLE.

• One Oconee Unit 1 S breaker AC Sources - Operating are part of the pii mary success path and capable of feeding function to mitigate an accident or t ransient that presents a challenge to switchgear 1TC; the integ rity o a fission product barrier. As such, AC Sources -

• SWitchgear 1TC Operating, satisfies the requirements of Criter i.o n 3 of 10 CFR 50.36 capable of feeding (Ref. 3).

Keowee auxiliary transfom1er CX; and Two sources on separate towers connected to the 230 kV switchyard to a

• Keowee Load unit startup transformer and one main feeder bus are required to be Center ( 1X or 2X) OPERAB LE Two KHUs vvith one capable of automatically providing Transfer Switch in pmiver through the underground emergency po*,iver pa1h to both main Automatic. feeder b uses and the other capable of automatically providing pow er through the ovemead emergency power path to both main feeder buses The additional features are required to be OPERABLE. The Keowee Reservoir level is required' are required to ensure an to be _ 775 feet above sea level to support OPERABILITY of the KHUs.

alternate auxiliary power The zone overlap protection circuitry is ,required to be OPEHABLE 1.men source for the KHU the overhead electrica! disconneots for the KHU associated with ,the assigned to the overhead underg:round power path are closed to provide single failure protection for po ,rer path for a the KIH Us_ T he zone overlap protection circuitry includes the step-up postulated single failure transformer fockout, 1he underground KHU lockout, the Keowee mitigated by the Zone emergency start signal, .aoo-the underground breaker for the overhead Overtap Protection KHLi.fto ensure the zone overl ap proteotion cir,cuitry logic is OP6RABL Circuitry.

, and the following additional features for the overhead KHU OCONEE UNITS 1, 2, & 3 B 3.8_1-2 Rev_OOl I

License Amendment Request No. 2017-05 May 17, 2018 AC Sources - Operating 1B 3'8.1 BASES SURVEILLANCE SR 3.8.1.16 (continued}

REQUIREMENTS This SR is modified by a Note indicating that the SR is only app~cable SR 3.8.1.18 when complying with Required Action C.2.24.

This SR verifies the ability of each KHU auxiliary power SR 3.8. 1.17 system to automatica y transfer from its nonnal This SR verifies the Keowee Voltage and Frequency out of ,to erance awiliary power soorce to ~s logic trips and blocks d osure of the appropriate overhead or underground alternate auxiliary power power path breakers on an out of to erance trip signat The Surve~ lance source. The Surve anoo Frequency is based on opera.ting e)(Jlefience, equipm.ent reliability, and Frequency is based on plant risk and is control ed under 1he Survei !lance Frequency Control operali1g experience, Program.

equipment reliabiity, and ~ant risk and is cootrolled under the There are three over voltage relays, three under voltage relays, and three

~rveillaooe Frequency over/under frequency relays per KHU with each relay actuating an Control Program. au~ilia:ry relay used to provide ti.r.*o o.ut of three logic. These relays monitor generator output voltage and if two phases are above/beJO'N Testing demonstrates the setpoint, prevent the power path breakers from closing or if dosed, abi1ity of each KHU 600 Volt provide a trip signal which is applied after a time delay, to open the pioiA'er Auxiliary Load Center 1X a 2X path brea ers. Testing demonstrates that relays actuate at preset to dose its alternate feeder values, that timers time out and that two under voltage relays, two over tx"eaker after time delay from voltage relays, or two over/under frequency relays will actuate the logic

~s lllJ!'ma feeder breaker channel_ This ensures 1hat the power path breakers wilJ not close and if opening whether as the dosed, will trip after a preset time delay that becomes effectiv e when the L111dergroond or ovemead KHU first reaches 1he required frequency and voltage band .

power path um.

REFERENCES 1. UFSAR, Section 3.1..39 2.. UFSAR, Chapt er 16

3. 10 CFR50.36

4. UFSAR, Chapter 6

5. UFSAR, Chapter 15

6. U FSAR, Section 6.3.3.3 OCONEE UNITS 1, 2, & 3 B 3.8. 1-26 Rev. OOJ I

License Amendment Request No. 2017-05 May 17, 2018 -.

ATTACHMENT 3 RETYPED TECHNICAL SPECIFICATIONS PAGE

[1 page follows this cover page]

NOTE: This attachment contains retyped TS page 3.8.1-17.

License Amendment Request No. 2017-05 May 17, 2018 AC Sources - Operating 3.8.1 SURVEILLANCE REQUIREMENTS (continued)

SURV EILLANCE FREQUBNCY SR 3.8.1.16 ~~~~~~u *, ~~O T E~~~~~~

Only applicable when complying with Required Action C2.2.4.

Verify one KHU provides an alternate manual As specified by Required AC power source capability by manua or Action C-2.2-4 automatic KHU start with manual synchronize, or breaker dosure, to energize its non-required emergency power path.

SR 3.8.1.17 Verify each KHU's Voltage and Frequency out [n accordance with the of to erance logic trips and blocks closure of Surveillance Frequency the appropriate overhead or underground Control Program power path breakers. The allowable values with a time de4ay of 5 seconds +/- 1 second shall be as follows: *

a. Undervoltage ~ 12.42 kV and ~ 12.6 3 kV

b. Overvoltage ~ 14.90 kV and ~ 15.18 kV

c. Underfrequency ~ 53.992 hz and

~ 54.00S hz

d. Overfrequency ~ 65.992 hz and

~ 66.00Shz SR 3.8.1.18 Verify the .ability of each KHU auxi~ary pa.ver tn accordance with the system to automatically transfer from its Surveillance Frequency normal auxifiary power source to its alternate Contra Program

• auxiliary po"'rer source.

OCO EE U ITS 1, 2, &3 3.8.1-17 Amendment Nos.

License Amendment Request No. 2017-05 May17, 2018 ATTACHMENT 4 MARKED-UP UPDATED FINAL SAFETY REPORT PAGES

[3 pages follow this cover page)

NOTE: This attachment contains marked-up UFSAR pages 8.3-2 & 8.3-7 and page 2 of 2 of Table 8.3-2.

License Amendment Request No. 2017-05 May 17, 20 18 Insert new paragraph: The auxiliaries for the unit aligned to the underground

. feeder receive power from Transformer CX. The auxilianes for the unit aligned to 8

UfSAH Chap ter the overhead feeder receive power from Auxiliary Transformer 1X or 2X. The power source for each alignment is referred to as the normal source.

by control signals from eithe:r Oconee control area. Normal startup of eithe:r unit is by operator action while emergency startup is automatic. Both units are started automatically and simultaneously and run on standby on either of three conditions: 1

• external grid trouble p:rotection system actuation, 2) engineernd safeguards actuation or 3) main feeder bus monitor undervoltage actua *on. If the units are already operating 1hen any of the above conditions occur, they are separated from the network ( and momentarily from the underground path) and continue to run on standby until needed. Each unit's vo l age regulator is equipped wh a vo lts-per-cycle limitir.g feature wtiich pem1its it o accept full emergency power lo. d as it accelerates from zero to full speed ithin 23 seconds from receipt of the emergency startup in* *ation signal.

On noon al autom atic startup, each unit is automatically connected and supplies power to the Oconee 230 kV switching station through lhe stepup transformer by its respective generator air circuit breakier. This is acoomplished by the automa *c synchronizing equipmen of each unit On emergency automatic startup, both units are started; the unit *ith the underground feeder se lected to

• sup~ ies that feeder and the other unit is available to supply the Oconee 230 kV switching station. If there is a system disturbance, this unit is connected automa ically to the Oconee 230 kV YellO' Bus on y after the Oconee 230 kV Yellow Bus is isolated autom atically from the system and the preset time delay has elapsed. Redundant External Grid Trouble Protective System s are provided lo isolate the 230 kV sw itching station on failtJre of the external transm ission netvuork. Therefore, on loss of the extema transmission net ,,ork, both of the Keowee hydro nits can p.-o *ide emergency power to any of the Oconee u 1jts through either the 230 kV switchir.g s ation to the un* s respective sta up transfom1e.r or the undergroond feeder and Transfom,er CT4 at Oconee.

Pow er from the hydro units is available excep

• when:

1. Both units are out of service, or

2. There is a coincident fai ure of the underground feeder cir cuit and a complete outage of the 230 kV feeder circuit through the sv.1tching station.

The Standby Shutdown Facility (SSF , consists of standby systems for use in extreme

• emergency conditions. f ollowing 1he loss of all norma and emergency po *ler, on-site and off-site, the SSF diesel electric generating unit will be manually started by initiating the start signal from the SSF Control Panel in the SSF. The SS F Electrical Pm*;er System supplies power neoessa to maintain ho shutdovvn of the reactors of each uni in the event of loss of po*,,.,er from all o er power systems.

The SSF is described in detail in Section 9.6. The SSPs role in SBO roping is discussed in Secliioo 8.3.2.2.4.

8 .3.1.1..2 6900 Volt A 1xiliary System The 6900 volt aLIXiliary system for each unit is designed to supply electri c power to the 9000 horsepo.ver reactor coolant pump molars. This system is arranged into two bus sections. Both bus sections feed *nto t*uo s witchgear bus sections, ea.c h feeding two mo ors. Each S1J11itchgear bus supplies one motor for each of the two reactor coolant pipir.g loops. Either the 1it aLIXiliary or the startup transformer is capable of feeding both s *.iitchgear buses. During startup, shutdown and after shutdO'OO , the switcligear buses are supplied from the startup transformer.

During normal Opefa *on, the s *.~ chgear buses are supp~ed from the unit auxiliary transformer.

Normal bus transfers between Hie tilto sources are initiated at the cfiscre *on of the operator from the control room , while emergency transfer from the unit auxiliary to Hie startup transfom \er is initiated automatically by protective relay action_ Normal bus transfers used on startup or shutdown of a L1nit are li¥e bus* transfers , i.e ., the incomir.g source feeder cir cuit breaker is

8. 3 - 2 (31 DE C 2015)

License Amendment Request No. 2017-05 Attachment 4 May 17, 2018 Selected Licensee Commitment 16.8-4 specifies operating restrictions during commercial power generation by one or both Keowee Hydro Units.

Oconee N uc_lear Station These restrictions ensure that the units are able to_perform their emergency power function from an initial condition of commercial power generation.

equipment, protective relaying, automatic startup control equipmen , manual controls, unit de control battery, etc.

If one hydro unit is out for main1enance, the other unit is available for service. The two units are served by a common tunnel-penstock, and unwatering for tunnel or scroll case maintell3nce uilt make both units unavailable. Based upon Duke's experience since 1919 ith a hydro station similarly arranged, it is expected that unwatering frequency will be about one day per year plus four days every tenth year.

During all periods hen the Keowee units are available for emergency power service, the Keowee Hydro Headgate Vllill be rigidly fastened to assure that fail ure of the hoist system mll not pem1in he gate to move into the closed position.

The independent Keawee units, along with the alterna1e circuits, provide the required redundancy to assure reliable emergency power. The Keowee reservoir and naturally occurring streamflow provide the *.rater for the Keowee units so they can provide emergency po ver following an accident Selected licensee Commitment 16.9.7 contains lake level

.--- +

information associated 11ith the Lake Keowee water supply for the Keowee Hydro Station . ...:-<::----

he failure analysis covering the Keowee Hydro Station is ouHined in Table 8-3.

3. Each electric power distribution sys1em is designed ith redundant full capaci buses to match the capaci o the large emergency po,ver source. This thereby provides hivo continuous sour ces of supply from e two full capaci main feeder buses to each of the three engineered safeguar ds s 'Jitchgear buses.

4. Reliability of the engineered safeguards S'lfllitchgear buses is assured by the follO'Wing protective features:

a. 4 160 V engineered safeguards (ESG) switchgear bus overload and bus fautt cond* *ans are pro1ected for by both ground fau overcurrent relays and phase overcurrent relays.

These relays are provided on each ESG switchgear bus breaker and function to open the associated breaker to isolate the ESG switchgear bus from the main feeder buses, thereby maintaining the integrity of the main feeder buses.

b. Each ESG switchgear feeder breaker is also included in the zone of protection afforded by the main feeder bus differential current relays 'Vhich rould function to isolate a fautted breaker from any source of supply.

c. Each ESG s \1tchgear feeder breaker is provided *ith breaker failure protective relaying.

This feature vi I initiate action to isolate the breaker from any source of supply if the breaker ails to open upon a protective relay trip. The maxjmum equipment this would

remove from service is one ESG switchgear bus and one main feeder bus, leaving hivo ESG s

• chgear buses and the other main feeder bus to supply the required loads \l\ltiich are sufficient to perform the intended safe functions .

d. Each ESG sv,1tchgear feeder breaker is provided 1ith redundant trip coils, suppljed from separate de supplies, assuring positive trip action.

With the Insert new paragraph: Zone Over1ap Protection Circuitry d the physical separation provides single failure protection of the Keowee Hydro hgea buses or co~ponen Units \Nhen the unit assigned to the underground path is to supply thei r engineere commercially generating to the grid. Singe failures in the

5. Reliability Zone Over1ap Region result in automatically realigning the y the follo 1ving protective f unit assigned to the overhead path to the underground

,___ _ _ _,..ath. For single failures mitigated by the Zone Overtap Protection Circuitry, Auxiliary Power Transfer Circuitry

( 31 DEC 201 51 automatically realigns the power source for the aux:lliaries 8.3- 7 from the normal source to the alternate source to ensure continued operation of the units.

License Amendment Request No. 2017-05 AttaGhment 4 May 17, 2018 Oconee Nuclear Station UFSAR Table 8-3 (Page 2 of 2)

Component Malfunction Comments & Consequences

8. Keowee Hydro Loss of one No Consequence, .since independent Unit Emergency and redundant underground signal Startup and cables are provided.

Switching Circuits from Oconee

.--U-n_d_er_g_ro-un_d_ _ _L_o_ss_of_u_n_d_e_rg_r_o_un-d-.___Ov_e_rh_e_a_d_as_s,g

___n_e_d_Ki_eov.

__ -ee_H_y_d_ro_U_ni_t__

[ assigned Keowee . assigned Keowee Hydro would be automaticalty realignedto provide Hydro Unit Unit and overhead path power to underground path. Auxi[iary generating to the loads for overhead assigned Keowee grid during Hydro Unit would be automatically commercial realigned to receive power from generation or Transformer CX testing