ML19206A056
| ML19206A056 | |
| Person / Time | |
|---|---|
| Site: | Peach Bottom  |
| Issue date: | 07/24/2019 |
| From: | David Helker Exelon Generation Co |
| To: | Document Control Desk, Office of Nuclear Reactor Regulation |
| References | |
| Download: ML19206A056 (11) | |
Text
Exelon Generation 200 Exelon Way Kennett Square. PA 19348 www.exeloncorp.com 10 CFR 50.90 July 24, 2019 U.S. Nuclear Regulatory Commission Attn: Document Control Desk Washington, DC 20555-0001 Peach Bottom Atomic Power Stations, Units 2 and 3 Renewed Facility Operating License Nos. DPR-44 and DPR-56 NRC Docket Nos. 50-2n and 50-278
Subject:
Response to Request for Additional Information - License Amendment Request to Revise Technical Specifications 3.8.1, Required Action A.3, for Temporary One-}"ime Extension of Completion Time
References:
- 1. Letter from James Barstow (Exelon Generation Company, LLC) to U.S. Nuclear Regulatory Commission - "License Amendment Request to Revise Technical Specifications 3. 8. 1, Required Action A. 3, for Temporary One-Time Extension of Completion Time," dated April 26, 2019 (ML19116A196)
- 2. James Barstow (Exelon Generation Company, LLC) to U.S. Nuclear Regulatory Commission - "Supplemental Response for License Amendment Request to Revise Technical Specifications 3.8.1, Required Action A.3, for Temporary One-Time Extension of Completion Time," dated May 23, 2019 (ML19143A176)
- 3. Electronic mail message from Jennifer Tobin (U.S. Nuclear Regulatory Commission) to David Helker, Exelon Generation Company, LLC- "Peach Bottom Units 2 and 3-Request for Additional Information - Replacement Buried Cable LAR- (Temporary)
Extension of Completion Time (EPID L-2019-LLA-0095}," dated June 27, 2019 (ML19178A332)
By letter dated April 26, 2019 (Reference 1), Exelon Generation Company, LLC (Exelon) requested amendments to Renewed Facility Operating License Nos. DPR-44 and DPR-56 for Peach Bottom Atomic Power Station (PBAPS), Units 2 and 3, respectively. The proposed changes involve revising the PBAPS, Units 2 and 3, Technical Specifications (TS) to support a temporary one-time extension of the Completion Time for TS Section 3.8.1, "AC Power -
Operating," Required Action A.3, frpm seven (7) days to 21 days. This temporary one-time TS change is needed to allow sufficient time to perform physical modification work to replace 27 electrical cables from the 3EA Emergency Auxiliary Transformer to the J-58 junction box serving the 3SU-E 4.16 kV feed switchgear. Exelon supplemented the Reference 1 amendment request by letter dated May 23, 2019 (Reference 2).
U.S. Nuclear Regulatory Commission Response to Request for Additional Information 3EA Cable Replacement License Amendment Request Docket Nos. 50-277 and 50-278 July 24, 2019 Page2 The NRC reviewed the information provided in References 1 and 2 and indicated the need for additional information in order to complete its review and evaluation of the amendment request. In an electronic mail message dated June 27, 2019, the NRC issued a Request for Additional Information (RAI) (Reference 3). The NRC previously issued the RAI as a draft on June 20, 2019, and provided Exelon an opportunity to further discuss the RAI to ensure the questions are understandable. A teleconference was held on June 27, 2019, between Exelon and NRC representatives regarding the RAI and Exelon agreed to respond within 30 days of the issuance of Reference 3 request.
The Attachment to this letter provides a restatement of the RAI questions cited in Reference 3 followed by Exelon's responses.
Exelon has reviewed the information supporting a finding of no significant hazards consideration, and the environmental consideration, that were previously provided to the NRC in the Reference 1 letter. Exelon has concluded that the information provided in this response does not affect the bases for concluding that the proposed license amendment does not involve a significant hazards consideration under the standards set forth in 10 CFR 50.92. In addition, Exelon has concluded that the information in this response does not affect the bases for concluding that neither an environmental impact statement nor an environmental assessment needs to be prepared in connection with the proposed amendment.
This submittal includes an updated regulatory commitment as further discussed in the Attachment to this letter.
In accordance with 10 CFR 50.91, "Notice for public comment; State consultation,"
paragraph (b), Exelon is notifying the Commonwealth of Pennsylvania of this RAI response by transmitting a copy of this letter and its attachments to the designated State Official.
If you have any questions or require additional information, please contact Richard Gropp at 610-765-5557.
I declare under penalty of perjury that the foregoing is true and correct. Executed on the 24th day of July 2019.
Respectfully, g.4 ~~
David P. Helker Sr. Manager, Licensing Exelon Generation Company, LLC
Attachment:
Response to Request for Additional Information - License Amendment Request to Revise Technical Specifications 3.8.1, Required Action A.3, for Temporary One-Time Extension of Completion Time
U.S. Nuclear Regulatory Commission Response to Request for Additional Information 3EA Cable Replacement License Amendment Request Docket Nos. 50-277 and 50-278 July 24, 2019 Page 3 cc: w/ Attachment Regional Administrator - NRC Region I U.S. NRC Senior Resident Inspector - Peach Bottom Atomic Power Station U.S. NRC Project Manager, NRR - Peach Bottom Atomic Power Station Director, Bureau of Radiation Protection - Pennsylvania Department of Environmental Protection R. R. Janati, Pennsylvania Bureau of Radiation Protection D. A. Tancabel, State of Maryland
ATTACHMENT License Amendment Request Peach Bottom Atomic Power Station, Units 2 and 3 Docket Nos. 50-277 and 50-278 Response to Request for Additional Information - License Amendment Request to Revise Technical Specifications 3.8.1, Required Action A.3, for Temporary One-Time Extension of Completion Time
Attachment Response to Request for Additional Information Revise TS 3.8.1 to Support Cable Replacement Docket Nos. 50-277 and 50-278 Page 1 of 7 Attachment Response to Request for Additional Information - License Amendment Request to Revise Technical Specifications 3.8.1, Required Action A.3, for Temporary One-Time Extension of Completion Time By letter dated April 26, 2019 (Reference 1), Exelon Generation Company, LLC (Exelon) requested amendments to Renewed Facility Operating License Nos. DPR-44 and DPR-56 for Peach Bottom Atomic Power Station (PBAPS), Units 2 and 3, respectively. The proposed changes involve revising the PBAPS, Units 2 and 3, Technical Specifications (TS) to support a temporary one-time extension of the Completion Time for TS Section 3.8.1, "AC Power -
Operating," Required Action A.3, from seven (7) days to 21 days. This temporary one-time TS change is needed to allow sufficient time to perform physical modification work to replace 27 electrical cables from the 3EA Emergency Auxiliary Transformer to the J-58 junction box serving the 3SU-E 4.16 kV feed switchgear. Exelon supplemented the Reference 1 amendment request by letter dated May 23, 2019 (Reference 2).
The NRC reviewed the information provided in Reference 1 and indicated the need for additional information in order to complete its review and evaluation of the amendment request. In an electronic mail message dated June 27, 2019, the NRC issued a Request for Additional Information (RAI) (Reference 3). The NRC previously issued the RAI as a draft on June 20, 2019, and provided Exelon an opportunity to further discuss the RAI to ensure the questions are understandable. A teleconference on June 27, 2019, between Exelon and NRC representatives regarding the RAI and Exelon agreed to respond within 30 days of the issuance of Reference 3 request.
The questions are restated below followed by Exelon's response to each question.
Request for Additional Information (RAI) 1 The LAR states that Peach Bottom plans to meet the intent of NUREG-0800, Branch Technical Position (BTP) 8-8, "Onsite (Emergency Diesel Generators) and Offsite Power Sources Allowed Outage Time Extensions," by proposing additional defense-in-depth actions and procedures and using a currently installed alternate alternating current (AAC) power source (station blackout (SBO) line) to provide supplemental AC power to station emergency buses, as required to compensate for inoperable AC sources.
NUREG-0800, BTP 8-8 provides guidance, from a deterministic perspective, for reviewing a one-time completion time extension request. Section B of BTP 8-8 states, in part:
[Technical Specification] TS required systems, subsystems, trains, components, and devices that depend on the remaining power sources will be verified to be operable and positive measures will be provided to preclude subsequent testing or maintenance activities on these systems, subsystems, trains, components, and devices.
To address the above BTP 8-8 position, Section 4.0 of Attachment 1 to the LAR states, in part, that the remaining operable offsite circuit, diesel generators (DGs), and SBO line will be controlled as protected equipment. This statement appears to satisfy the BTP position with respect to precluding the remaining operable offsite circuit, DGs, and SBO line from testing or
Attachment Response to Request for Additional Information Revise TS 3.8.1 to Support Cable Replacement Docket Nos. 50-277 and 50-278 Page 2 of 7 maintenance activities during the requested extension of the CT to 21 days. However, of the LAR states that preplanned maintenance affecting DGs or operable offsite circuits will be assessed within existing process to ensure that station Operations staff will not authorize preplanned maintenance activities affecting DGs or operating offsite circuits during the temporary onetime 21-day extended completion time period if severe adverse weather conditions are expected.
It appears that Attachment 3 of the LAR implies that the operating offsite circuit and DGs are not precluded from testing and maintenance during the 21-day extended completion time period and that testing and maintenance on the operating offsite circuits and DGs during the 21-day extended completion time period will be precluded only when the severe weather conditions are expected. Please provide a discussion of how the proposed change meets the BTP 8-8 position.
Response
As discussed in the Reference 1 submittal, the remaining operable offsite circuit, four (4)
Emergency Diesel Generators (EDGs), and Station Blackout (SBO) line will be controlled as protected equipment. Required surveillances will be completed to determine and ensure operability of the equipment prior to entry into the temporary one-time 21-day Completion Time period. Plant Operations will not authorize planned maintenance on any equipment that is protected while the 3EA circuit is blocked, regardless of weather conditions. The statement referenced in Attachment 3 as discussed in the RAI question above was intended to provide the process for re-evaluating work and equipment during inclement weather and not that the equipment would be protected only during inclement weather. No unnecessary work will be authorized on or around the protected remaining operable offsite circuit, EDGs, and SBO line during the 3EA circuit system outage window. This equipment will remain protected throughout the duration of the extended Completion Time period and no unnecessary work will be authorized on or around the protected equipment during the 3EA circuit system outage window.
As discussed in Attachment 3 of the Reference 1 License Amendment Request (LAR), the following compensatory measure (i.e., Regulatory Commitment), which is one of several actions, was noted in support of temporarily extending the TS Completion Time:
Attachment Response to Request for Additional Information Revise TS 3.8.1 to Support Cable Replacement Docket Nos. 50-277 and 50-278 Page 3 of 7 COMMITMENT TYPE COMMITTED DATE COMMITMENT OR "OUTAGE" ONE-TIME ACTION PROGRAMMATIC (YES/NO) (YES/NO)
Preplanned maintenance affecting Throughout the Yes No Emergency Diesel Generators one-time 21-day (EDG) or operable offsite circuits extended will be assessed within existing Completion Time process to ensure that station period.
Operations will not authorize performance of pre-planned maintenance affecting EDGs or operating offsite circuits during the temporary one-time 21-day extended Completion Time period if severe adverse weather conditions are expected.
Exelon is superseding the previously proposed commitment (as described above) with the following commitment to clarify that the remaining operable offsite circuit, EDGs, and SBO line will be maintained as protected equipment and no pre-planned maintenance will be authorized during the extended Completion Time period, and the reference to weather conditions has been removed:
COMMITMENT TYPE COMMITTED DATE COMMITMENT OR "OUTAGE" ONE-TIME ACTION PROGRAMMATIC (YES/NO) (YES/NO)
Once the 21-day extended Throughout the Yes No Completion Time period is one-time 21-day entered, work will continue on extended replacing the cables regardless of Completion Time weather conditions unless period.
deemed unsafe, and surveillance testing and maintenance affecting the Emergency Diesel Generators (EDGs), SBO line, or operable offsite circuit will be assessed within existing process to ensure that station Operations will not authorize performance of unnecessary work affecting the EDGs, SBO line, or operating offsite circuit during the temporary one-time 21-day extended Completion Time.
Attachment Response to Request for Additional Information Revise TS 3.8.1 to Support Cable Replacement Docket Nos. 50-277 and 50-278 Page 4 of 7
RAI 2
Section B of BTP 8-8 states, in part:
The preplanned maintenance will not be scheduled if severe weather conditions are anticipated.
The LAR states that preplanned maintenance affecting DGs or operable offsite circuits will be assessed within existing Procedures/Processes WC-AA-101, "On-line Work Control Process,"
and WC-AA-104, "Integrated Risk Management." These processes will ensure that station Operations staff would not authorize performance of preplanned maintenance affecting DGs or operable offsite circuits during the requested extension of the CT if severe adverse weather conditions are expected. It appears that the term preplanned maintenance is mischaracterized as the maintenance of the DGs and operable offsite circuits. It should be noted that the term preplanned maintenance in BTP 8-8 applies to activities associated with the proposed extended completion time, and in this case, it is the cable replacement activities.
It is not clear if the cable replacement activities are scheduled when severe weather is anticipated. Please provide a discussion of the proposed actions and regulatory commitments for scheduling the cable replacement activity if severe weather conditions are anticipated during the proposed extension of the CT to 21 days.
Response
The 3EA circuit cable replacement work is being scheduled during a time of the year when, historically, severe weather is not expected. Weather conditions during the time of year selected (i.e., late fall) are typically favorable and suitable for supporting the type of work to be performed.
The 3EA cable replacement activities will be worked continuously until completion. In the event that unsuitable weather conditions are experienced during the extended 21-day Completion Time period, the station can evaluate the working conditions and institute appropriate measures to support work activities, unless severe weather makes it unsafe. The proposed temporary 21-day Completion Time schedule for replacing the cables does include some contingency time for potential weather delays that could inhibit the cable replacement activities if unsafe conditions exist. Once the work has commenced, the remaining operable offsite power circuit, EDGs, and SBO line will remain protected regardless of weather conditions during the 3EA circuit system outage window as discussed in response to RAI 1 above.
Should extreme or adverse weather conditions be forecasted for the currently scheduled outage period (i.e., late fall) the project start date could be delayed, or the entire project schedule could be moved. This determination will be made by Plant Operations the week prior to the start of the currently scheduled system outage window.
RAI 3
Section B of BTP 8-8 states, in part:
The plant should have formal engineering calculations for equipment sizing and protection and have approved procedures for connecting the AAC or supplemental power sources to the safety buses.
Attachment Response to Request for Additional Information Revise TS 3.8.1 to Support Cable Replacement Docket Nos. 50-277 and 50-278 Page 5 of 7 To address the above BTP 8-8 position, Section 4.0 of Attachment 1 to the LAR states, in part, that the existing DG loading Calculation PE-0166, "Emergency Diesel Generator Loading for Cases defined by UFSAR," confirms the capability of the DGs to meet the shutdown load requirements. The LAR also provides a list of the DG loads and a discussion of the four Class 1E DGs as supplemental power sources. It should be noted that the emergency diesel generators are part of the required onsite power system. These DGs should not be credited as the AAC or supplemental power sources. The AAC or supplemental power source is defined by BTP 8-8 as the power source that has capability and capacity to carry all loss of offsite power (LOOP) loads and bring the unit to a cold shutdown in an event of loss of the offsite electric power system concurrent with reactor trip and unavailability of the onsite emergency AC electric power system. For the purpose of this review, the NRC staff considers the SBO line as the Peach Bottom AAC or supplement power source. However, in the LAR, it is not clear:
a) Whether the SBO line has the capability and capacity to power (1) both units safe shutdown system loads (loads listed in Attachment 6 of the LAR); and (2) both units systems and components listed in LCO 3.8.1.c that are currently required to be powered by the offsite circuits.
b) Whether Peach Bottom has a procedure for connecting the SBO line to the safety buses for both units.
Please provide a discussion for Items a and b above.
Response
The requested responses to Items a and b are discussed below.
Item a The SBO line and transformer are designed for minimum safe shutdown loading for both units, i.e., one (1) Residual Heat Removal (RHR) pump per unit, one (1) High Pressure Service Water (HPSW) pump per unit, essential battery chargers, essential Heating, Ventilation and Air Conditioning (HVAC) loads, and other small electrical loads for equipment.
From Calculation PE-0154, "Station Blackout Voltage Regulation - Conowingo Source," the loads listed below are expected to be supplied from the SBO line, which would include loads specified in Limiting Condition for Operation (LCO) 3.8.1.c except for the Emergency Heat Sink.
PBAPS Accident and Transient Analyses do not assume an SBO condition concurrent with a loss of the Conowingo Pond. Within LCO 3.8.1, SBO line availability permits an extension of the allowable out of service time for an EDG to 14 days from the discovery of failure to meet LCO 3.8.1.a or b (per Required Action B.5). SBO line operability is covered by the Technical Requirements Manual (TRM) Section 3.18. LCO 3.8.1.c names loads normally powered by the offsite circuit that are required to be OPERABLE for both PBAPS units, prompting the station to enter LCO 3.8.1 on both units should that particular circuit become INOPERABLE. For example, 0BV020, the "B" Standby Gas Treatment (SBGT) fan is required to be operable for both Units 2 and 3 (LCO 3.6.4.3). Should the qualified circuit between the offsite transmission network and the Unit 2 onsite Class 1E AC electrical power distribution subsystem (E22 4KV bus in this case) become inoperable, LCO 3.8.1 Condition A must be entered for both units, because 0BV020 is required to be OPERABLE by LCO 3.6.4.3 for both units.
Attachment Response to Request for Additional Information Revise TS 3.8.1 to Support Cable Replacement Docket Nos. 50-277 and 50-278 Page 6 of 7 Loads expected to be supplied from the SBO Line:
RHR Pumps HPSW Pumps Emergency Service Water (ESW) Pumps Emergency Lighting 24V Battery Chargers 125V Station Battery Chargers Main Control Room (MCR) Emergency Vent Supply Fans Emergency Switchgear Vent Supply and Exhaust Fans Battery Room Vent Exhaust Fans Emergency Core Cooling System (ECCS) (and Reactor Core Isolation Cooling (RCIC))
Room Coolers SBGT Exhaust Fans and Filter Train Heaters Backup Station Air Compressors Various Instrument Panels and Uninterruptable Power Supply (UPS) Power Other Miscellaneous Loads including:
o HPSW/Emergency Service Water (ESW) Vent Supply and Exhaust Fans o SU-25 Breaker Auxiliaries o Various Y-Panels The SBO line is referenced in Design Basis Document (DBD) No. P-T-13, "Station Blackout," as a PBAPS Alternate AC (AAC). Section 3.4 of the DBD describes in part:
PBAPS has opted to use an Alternate AC (AAC) approach to cope with and recover from a station blackout. The PBAPS SBO AAC source utilizes a 34.5 kV submarine feed from the Conowingo hydroelectric station which is located down river from PBAPS. The design of the AAC power source utilized at PBAPS is documented in the NRC's SER for Station Blackout issued to PBAPS 10/23/92.
The Conowingo tie-line terminates at the SBO substation which is located within the PBAPS protected area. The SBO substation is a stand-alone facility comprised of 34.5 kV and 13.8 kV metal clad outdoor walk-in switchgear, a 15/20 MVA oil filled 34.5 kV - 13.8 kV transformer and associated controls. This AAC source is required to be manually connected to the Unit 2 13.8 kV startup bus 00A03C within one hour of the onset of a SBO as part of the overall PBAPS SBO coping strategy. Power to Unit 3 safety related buses is made available through the operation of 4 kV tie breakers. The Conowingo line and supporting equipment are non-safety related.
BASIS: The QA and system and equipment design specifications for the Conowingo line and associated SBO switchgear meet the requirements of Appendices A & B respectively of Reg. Guide 1.155, NUMARC 87-00, and 10CFR50.63 for an AAC source.
Attachment Response to Request for Additional Information Revise TS 3.8.1 to Support Cable Replacement Docket Nos. 50-277 and 50-278 Page 7 of 7 In addition, the Conowingo tie-line (SBO line) was most recently tested in 2015 and was demonstrated to start and carry 7000 kW of load.
Item b Plant Procedure SE-11, "Loss of Offsite Power," directs the performance of Procedure SE-11.1, "Operating Station Blackout Line During LOOP Event." SE-11.1 provides instructions for operating the SBO line during a Loss-of-Offsite Power (LOOP) event when the station EDGs are not capable of supporting operation of safe shutdown loads. Procedure SE-11.1 specifically delineates the prerequisites, precautions, and procedural steps for connecting the SBO line to the safety buses for both units.
References:
- 1. Letter from James Barstow (Exelon Generation Company, LLC) to U.S. Nuclear Regulatory Commission - "License Amendment Request to Revise Technical Specifications 3.8.1, Required Action A.3, for Temporary One-Time Extension of Completion Time," dated April 26, 2019 (ML19116A196)
- 2. James Barstow (Exelon Generation Company, LLC) to U.S. Nuclear Regulatory Commission - "Supplemental Response for License Amendment Request to Revise Technical Specifications 3.8.1, Required Action A.3, for Temporary One-Time Extension of Completion Time," dated May 23, 2019 (ML19143A176)
- 3. Electronic mail message from Jennifer Tobin (U.S. Nuclear Regulatory Commission) to David Helker, Exelon Generation Company, LLC - "Peach Bottom Units 2 and 3 - Request for Additional Information - Replacement Buried Cable LAR- (Temporary) Extension of Completion Time (EPID L-2019-LLA-0095)," dated June 27, 2019 (ML19178A332)