PLA-6148, Proposed License Amendment Number 262, for Unit 2 Operating License No. NPF-22, Electrical Power Systems Technical Specification 3.8.1

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Proposed License Amendment Number 262, for Unit 2 Operating License No. NPF-22, Electrical Power Systems Technical Specification 3.8.1
ML070720545
Person / Time
Site: Susquehanna Talen Energy icon.png
Issue date: 03/02/2007
From: Mckinney B
Susquehanna
To:
Document Control Desk, NRC/NRR/ADRO
References
PLA-6148
Download: ML070720545 (21)
v • d • e


Text

Brltt T. McKinney PPL Susquehanna, LLC Sr. Vice President & Chief Nuclear Officer 769 Salem Boulevard

  • Berwick, PA 18603 MA 0 007 J J 1 ::.

Tel. 570.542.3149 Fax 570.542.1504 '

btmckinney@pplweb.com p p ii --

TM U. S. Nuclear Regulatory Commission Attn: Document Control Desk Mail Stop OP1-17 Washington, DC 20555 SUSQUEHANNA STEAM ELECTRIC STATION PROPOSED LICENSE AMENDMENT NUMBER 262 FOR UNIT 2 OPERATING LICENSE NO. NPF-22 ELECTRICAL POWER SYSTEMS TECHNICAL SPECIFICATION 3.8.1 PLA-6148 Docket No. 50-388 Pursuant to 10 CFR 50.90, PPL Susquehanna, LLC (PPL), hereby requests approval of the following proposed amendment to the Susquehanna Steam Electric Station (SSES)

Unit 2 Technical Specification (TS). The proposal would change Technical Specification 3.8.1 "Electrical Power Systems - AC Sources Operating."

This proposed change reflects a new ACTIONS Note 3 added to the SSES Unit 2 TS 3.8.1 "AC Sources - Operating," to allow a Unit 1 4160 V subsystem to be de-energized and removed from service to perform bus maintenance.

As demonstrated in the enclosed evaluation, the proposed amendment does not involve a significant hazard consideration.

This change is necessary to resolve issues that occurred during the Unit 1 outage in 2006.

At that time, Unit 2 was operating in Mode 1 and Unit I was in Mode 5. This proposed change provides an exception to the requirement to enter Unit 2 LCO 3.8.1 when performing bus maintenance on a Unit 1 4160 V bus.

In order to support planned Unit 1 4160 V bus maintenance during the spring of 2008 Unit 1 refueling outage, PPL requests approval of this proposed amendment by January 31, 2008. PPL further requests that the approved amendment be issued to be effective immediately upon approval with the implementation to be completed within 30 days.

The Enclosure to this letter provides the Evaluation of this Proposed Change to Technical Specification 3.8.1. Attachment 1 is the Technical Specification mark-up. Attachment 2 is a mark-up of the associated Technical Specification Bases changes provided for information.

Document Control Desk PLA-6148 There are no regulatory commitments associated with the proposed changes.

The need for this change has been discussed with the SSES NRC Project Manager, and it has also been reviewed by the SSES Plant Operations Review Committee and by the Susquehanna Review Committee.

In accordance with 10 CFR 50.91(b), PPL Susquehanna, LLC is providing the Commonwealth of Pennsylvania with a copy of this proposed License Amendment request.

If you have any questions or require additional information, please contact Mr. Duane L. Filchner at (610) 774-7819.

I declare under penalty of perjury that the foregoing is true and correct.

Executed on:

B. T. McKinney

Enclosure:

PPL Susquehanna, LLC Evaluation of Proposed Change to Unit 2 Technical Specification 3.8.1, "Electrical Power Systems - AC Sources Operating" Attachments: Proposed Change to Unit 2 Technical Specification 3.8.1, "Electrical Power Systems - AC Sources Operating" (Mark-ups) Proposed Change to Unit 2 Technical Specifications Bases 3.8.1, "Electrical Power Systems - AC Sources Operating" (Mark-ups provided for Information Only)

Copy: NRC Region I Mr. R. V. Guzman, NRC Project Manager Mr. R. R. Janati, DEP/BRP Mr. C. R. Welch, NRC Sr. Resident Inspector

Enclosure to PLA-6148 PPL Susquehanna, LLC Evaluation of Proposed Change to Unit 2 Technical Specification 3.8.1 "Electrical Power Systems -

AC Sources Operating"

1. DESCRIPTION
2. PROPOSED CHANGE
3. BACKGROUND
4. TECHNICAL ANALYSIS
5. REGULATORY SAFETY ANALYSIS 5.1 No Significant Hazards Consideration 5.2 Applicable Regulatory Requirements/Criteria
6. ENVIRONMENTAL CONSIDERATIONS
7. REFERENCES

Enclosure to PLA-6148 Page 1 of 14 PPL EVALUATION

Subject:

PPL Susquehanna Evaluation of Proposed Change to Unit 2 Technical Specification 3.8.1 Electrical Power Systems - AC Sources Operating

1. DESCRIPTION This proposed change to the PPL Susquehanna (PPL) Unit 2 Technical Specification 3.8.1 reflects a new ACTIONS Note 3 added to the SSES Unit 2 TS 3.8.1 to allow a Unit 1 4160 V subsystem to be de-energized and removed from service to perform bus maintenance.

PPL plans to implement this proposed Unit 2 TS amendment in early 2008 to support Unit 1 4160 V bus maintenance planned for the Unit 1 refueling outage during the spring of 2008.

2. PROPOSED CHANGE A mark-up of the proposed change to the Unit 2 Technical Specifications (TS) is included in Attachment 1 of this submittal. The Unit 2 TS 3.8.1 is revised to add new ACTIONS Note 3 as follows:

"When Unit I is in Modes 4 or 5 and an OPERABLE Unit 1 4160 V subsystem is placed in an inoperablestatus solely for the purpose ofperforming bus maintenance with both offsite circuits andfour requireddiesel generators otherwise OPERABLE, only entry into LCO 3.8.7 Condition C is required."

The plant configuration described by new ACTIONS Note 3 exists when Unit 2 is operating in Modes 1, 2, or 3, Unit 1 is in Modes 4 or 5, and a Unit 1 4160 V subsystem is de-energized and removed from service to perform bus maintenance. In this configuration, both the offsite power supplies continue to provide power to the remaining unaffected 4160 V subsystems (7 total) on both Units 1 and 2. In addition, the Diesel Generator (DG) that is associated with the de-energized Unit 1 4160 V subsystem remains capable of supplying power to its associated Unit 2 4160 V subsystem and the other 3 DG's are capable of supplying power to their associated buses on both units.

The ACTIONS Note 3 applies when both sources of offsite power remain energized and capable of supplying all the loads connected to the seven unaffected 4160 V buses on both Units 1 and 2. In addition, the associated DG remains capable of performing its required safety function for Unit 2. Therefore, the new ACTIONS Note 3 establishes an

Enclosure to PLA-6148 Page.2 of 12 exception to the definition of an OPERABLE offsite circuit and an OPERABLE DG, for performance of bus maintenance only. Entry into Unit 2 TS 3.8.1 Conditions A, B, and D is not required when deenergizing a Unit 1 4160 V subsystem solely for the purpose of performing bus maintenance.

The TS Bases Section B 3.8.1 has also been revised based on this change.

3. BACKGROUND During the Susquehanna Unit 1 Refuel and Inspection Outage 14 (Ul RIO14) in the spring of 2006, entry into Unit 2 TS 3.8.1 was not implemented appropriately to perform Unit 1 4160 V bus related maintenance. This resulted in a Condition Report that identified that the same problems (i.e. improper implementation of Unit 2 TS 3.8.1) occurred when performing Unit 1 4160 V bus maintenance during the U! RIO 13 in March 2004. Accordingly, these events were determined to be reportable and Licensee Event Report (LER) 50-388-2006-02 Rev. 0 was issued to the NRC on June 14, 2006 via PLA-6061. The need to change Unit 2 TS 3.8.1 was identified in LER 50-388-2006-02 as an action to prevent recurrence.

Susquehanna Units 1 and 2 each contain an onsite Class IE AC electrical power distribution system that is divided into redundant and independent AC electrical power distribution subsystems. The Class 1E AC distribution system for each unit consists of four*4160 V Engineered Safeguards System (ESS) buses, each bus having the capability to receive power from a primary and alternate ESS transformer connected to the offsite sources. In addition, four shared diesel generators (DGs) can be connected to the 4160 V ESS buses to provide emergency power in the event the primary and alternate offsite power sources are not available. Each DG supplies power to one ESS bus in Unit 1 and one ESS bus in Unit 2. Further, the AC electrical distribution system on each unit is divided into two divisions (Divisions I and II), each with redundant load groups, so that loss of any one load group does not prevent the minimum functions required by the safety analyses from being performed.

Portions of the Unit 1 AC Distribution System are shared between Units 1 and 2. The common equipment [Emergency Service Water (ESW), Standby Gas Treatment System (SGTS), Control Structure HVAC (CREOAS), and Control Room Floor Cooling] is energized only from the Unit 1 AC Distribution System. As such, some components that are required for Unit 2 operation receive power from the Unit 1 AC Distribution Subsystems. The Unit 1 AC Distribution Subsystems needed to support operation of the required Unit 2 equipment are listed in Unit 2 LCO 3.8.7, Table 3.8.7-1. Operation of the Unit 2 ECCS equipment supplied by the Unit 2 AC Distribution Subsystems is not affected by the Unit 1 4160 V bus maintenance activities discussed herein. Refer to

Enclosure to PLA-6148 Page 3 of 12 SSES Final Safety Analysis Report (FSAR) Sections 8.1.3 and 8.3.1 for further details and discussion including references to applicable drawings.

During unit outages, 4160 V buses are taken out of service to perform inspections and maintenance. This periodic maintenance assures proper operation during both normal and postulated accident conditions. The necessary steps and work group coordination required to de-energize the bus (and the associated offsite and DG feeder circuits to the bus) in an orderly fashion to perform bus inspection and maintenance, or to prepare for surveillance activities, are controlled by plant procedures. These procedures also provide the necessary steps and work group coordination to. complete the restoration of the bus and feeder circuits and remove temporary equipment and connections in order to assist in ultimately declaring the bus operable. The total elapsed time for these maintenance and inspection activities is between 50 and 60 hours6.944444e-4 days <br />0.0167 hours <br />9.920635e-5 weeks <br />2.283e-5 months <br /> as identified in the plant schedule. This includes concurrent entry into LCO 3.8.1 as necessary to perform bus feeder cubicle maintenance. The evolution below describes the workflow during a 4160 V bus outage under the proposed TS change:

" De-energize the bus per plant procedure; apply Clearance Order #1 on the bus feeder breakers. Enter LCO 3.8.7 Condition C (72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br />) and perform bus maintenance and inspection.

" Remove the associated DG from service Apply Clearance Order #2 on the DG, enter LCO 3.8.1 Condition D (12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br />) and perform maintenance and inspection of the DG power supply cubicle. Remove Clearance Order #2 and Exit LCO 3.8.1.D.

" Remove one offsite power supply from service. Apply Clearance Order #3 on the offsite source, enter LCO 3.8.1 Condition D (12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br />) and perform maintenance and inspection of the offsite power supply cubicle. Remove Clearance Order #3 and Exit LCO 3.8.1 D.

" Remove the other offsite power supply from service. Apply Clearance Order

  1. 4 on the offsite source, enter LCO 3.8.1 Condition D (12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br />) and perform maintenance and inspection of the offsite power supply cubicle. Remove Clearance Order #4 and Exit LCO 3.8.1 D.

" Remove Clearance Order #1 and Exit LCO 3.8.7 C.

The current TS require that when a Unit 1 subsystem is de-energized to perform bus maintenance, LCO 3.8.1 Conditions A, B, and D are entered because an offsite power circuit and a DG are declared inoperable. Condition A is entered because the determination of offsite circuit operability is made utilizing the definition of an OPERABLE offsite circuit as described in the LCO Section of Technical Specification

Enclosure to PLA-6148 Page 4 of 12 Bases 3.8.1. The LCO 3.8.1 Bases also describe that Condition B would be entered because "...the DG associated with the de-energized Unit 1 4160 V subsystem cannot connect to its respective ESS bus ... and accept required loads within the assumed loading sequence intervals." The LCO 3.8.1 Bases further establish that entry into Condition D for an inoperable offsite circuit and an inoperable DG results in a 12 hour1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br /> completion time because individual redundancy is lost in both the offsite electrical power system and the onsite AC electrical power system. The 12 hour1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br /> Completion Time takes into account the capacity and capability of the remaining AC sources, reasonable time for repairs, and the low probability of a DBA occurring during this period. However, 12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br /> is not sufficient to perform all the required bus related maintenance and inspection. The estimated time required to perform all the work is between 50 and 60 hours6.944444e-4 days <br />0.0167 hours <br />9.920635e-5 weeks <br />2.283e-5 months <br /> per the plant schedule.

This proposed change to Unit 2 TS 3.8.1, i.e. the addition of new ACTIONS Note 3, allows a Unit 1 4160 V ESS bus to be taken out of service to perform bus maintenance activities without requiring either the primary or alternate offsite power source or the DG associated with the affected bus to be declared inoperable. In this condition, only the affected Unit 1 4160 V ESS bus is de-energized. Both the primary and alternate power supplies from the ESS Transformers to the each of the unaffected 4160 V buses on both units remain energized. In addition, the associated DG remains capable of supplying power to its associated Unit 2 4160 V ESS bus. Therefore, both offsite circuits and the DG's remain capable of supplying power to the unaffected 4160 V ESS buses (7 total on both units).

4. TECHNICAL ANALYSIS Unit 1 4160 V ESS bus maintenance is performed when Unit 1 is in Modes 4 or 5 and Unit 2 is in Modes 1, 2 or 3. The common loads required for Unit 2 continued operation need to remain powered by Unit 1 4160 V ESS buses. Since the bus maintenance.

activities on Unit 1 affect the availability of only one bus, the remaining three 4160 V ESS buses on Unit 1 remain capable of supplying the required loads for Unit 2. This change to TS 3.8.1 is needed to provide sufficient time to perform the maintenance on a Unit 1 4160 V bus (i.e. 50-60 hours vs. 12 hrs currently limited by TS 3.8.1 Condition D).

The table below lists the common supported systems and the TS Conditions and Completion Times for one inoperable Unit 1 subsystem.

Common System Applicable LCO Completion Time (CT)

(One subsystem)

ESW 3.7.2 7 days SGTS 3.6.4.3 7 days CREOAS 3.7.3 7 days Control Room Floor Cooling 3.7.4 30 days

Enclosure to PLA-6148 Page 5 of 12 Only one subsystem would be affected by a Unit 1 de-energized and out of service bus.

In each case the minimum required Completion Time for one inoperable Division is 7 days. Therefore, the 72 hour8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br /> requested Completion Time to perform the bus maintenance is bounded and reasonable when compared to the affected systems.

Unit 2 TS 3.8.1 requires the following AC electrical power sources to be OPERABLE:

a. Two qualified circuits between the offsite transmission network and the onsite Class 1E AC Electrical Power Distribution System; and
b. Four diesel generators (DGs);
c. Two qualified circuits between the offsite transmission network and the Unit 1 onsite Class 1E AC electrical power distribution subsystem(s) required by LCO 3.8.7 "Distribution Systems - Operating"; and
d. The DG(s) capable of supplying the Unit 1 onsite Class 1E electrical power distribution subsystem(s) required by LCO 3.8.7.

A qualified circuit between the offsite transmission network and the onsite Class lE AC Electrical Power Distribution Subsystem consists of all breakers, transformers, switches, interrupting devices, cabling, and controls required to transmit power from the offsite transmission network to the onsite Class 1E ESS bus or buses. Currently, when a Unit 1 4160 V bus is de-energized for maintenance, the requirement that two qualified circuits and the DG's to be operable are not met, resulting in entry into LCO 3.8.1 Conditions A, B, and D. As stated above, the Completion Time for Condition D is 12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br />, which is not sufficient to perform bus maintenance activities. Accordingly, for a Unit 1 4160 V bus outage, new Unit 2 LCO 3.8.1 ACTIONS Note 3 is proposed to allow an exception to the requirement for two qualified circuits and an OPERABLE DG.

This exception will only be applied when Unit 1 is in Modes 4 or 5 and Unit 2 is in Modes 1, 2, or 3, during a Unit 1 4160 V subsystem outage in which both the primary and alternate offsite sources remain energized and four diesel generators remain capable of supplying the electrical AC power requirements of the combination of the remaining or unaffected Unit 1 4160 V ESS buses (common loads) and all four Unit 2 4160 V ESS buses (both Divisions). While in the Unit 1 bus maintenance configuration, sufficient power supplies are still available to meet all the necessary accident mitigation and safe shutdown requirements for Susquehanna, in accordance with General Design Criterion 17 as discussed in FSAR Section 8.3.1.11.

The following table shows how the proposed Unit 2 TS will be implemented compared to the current TS implementation:

Enclosure to PLA-6148 Page 6 of 12 Initial Conditions: Unit 1, Modes 4 or 5 Unit 2, Modes 1, 2, or 3 Desired work: A Unit 1 4160 V ESS subsystem bus is deenergized for bus maintenance (4160 V bus OOS).

Inoperable Equipment Current U2TS Condition Proposed U2 TS Condition C.omments Entries Entries Cmet Unit 14160 V Subsystem 3.8.1 3.8.7 CT 3.8.7 3.0.6 CT When the UI 4160 V subsystem is A3 72 hr C1 72 hr inoperable to perform bus maintenance, there is 1/2/of a Division of Common B4 72 hr equipment out of service. The shortest D2 12 hr completion time for this equipment in this Cl 72 hr condition is 7 days. (See the table above)

Thus 72 his is reasonable.

Unit 14160 V Subsystem and 3.8.1 3.8.7 CT Same as Cun-ent U2 TS Entries The loss of a DG requires entry into LCO subsequent DG (associated A3 72 hr 3.8.1 and Note 3 is no longer applicable.

with the same 4160 V Action D.2 establishes the 12 hour1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br /> B4 72 hr subsystem) D2 12 hr completion time.

Cl 72 hr Unit 1 4160 V Subsystem and 3.8.1 3.8.7 CT Same as Current U2 TS Entries The loss of a DG requires entry into LC0 subsequent DG (other than. A3 72 hr 3.8.1 and Note 3 is no longer applicable.

the DG associated with the B4 72 hr LCO 3.0.3 entry required immediately 4160 V subsystem) because one offsite source and 2 DG's are D2 12 hr inoperable.

Cl 72hr GI LCO 3.0.3 Unit 1 4160 V Subsystem and 3.8.1 3.8.7 CT Same as Current U2 TS Entries The loss of an offsite source requires a subsequent Offsite Source A3 72 hr entry into LCO 3.8.1 and the exception in 34 . 72 hr Note 3 is no longer applicable. LCO 3.8.1 Action D.I establishes the 12 hr DI1 12 hr completion time.

Cl 72 hr Unit 1 4160 V Subsystem and 3.8.1 3.8.7 CT Same as Current U2 TS Entries The loss of an ESS Transformer (part of a subsequent ESS A3 72 hr an offsite source) requires entry into Transformer B4 . 72 hr LCO 3.8.1 and the exception in Note 3 is Dl 12 hr no longer applicable. LCO 3.8.1 Action D. I establishes the 12 hr completion time CI 72 hr to restore the inoperable offsite circuit.

Unit 1 4160 V Subsystem and 3.8.1 3.8.7 CT Same as Current U2 TS Entries The loss of two ESS Transformers a subsequent loss of 2 ESS A3 72 hr connected to the same Startup Transformers connected to B4 72 hr Transformer requires entry into LCO the same Startup Transformer 3.8.1 and the exception in Note 3 is no DI 12 hr longer applicable. This loss is equivalent Cl1 72 hr to the loss of one offsite source.

Therefore, LCO 3.8.1 Action D.1 establishes the 12 hr completion time to restore the inoperable offsite circuit.

Unit 14160 V Subsystem and 3.8.1 3.8.7 CT Same as Current U2 TS Entries The loss of two ESS Transformers a subsequent loss of 2 ESS A3 72 hr connected to different Startup Transformers not connected B4 72 hr Transformers requires entry into LCO to the same Startup 3.8.1 and the exception in Note 3 is no Transformer D2 12 hr longer applicable. LCO 3.8.1 Action G I Cl 72 hr is required because 2 offsite sources and a GI LCO 3.0.3 DG are inoperable.

Unit 1 4160 V Subsystem and 3.8.1 3.8.7 CT Same as Current U2 TS Entries The loss of a subsequent Unit 2 4160 V a subsequent Unit 2 4160 V A3 72 hr subsystem requires entry into LCD 3.8.1 Subsystem de-energized. B4 72 hr and the exception in Note 3 is no longer applicable. However, LCO 3.8.7 Action D1, D2 12 hr A. I establishes the 8 hr completion Time C1 72 hr to restore the Unit 2 bus.

Al 8 hr

Enclosure to PLA-6148 Page 7 of 12 Inoperable Equipment Current U2 TS Condition Proposed U2 TS Condition Comments Entries Eties!K:'* .

Unit 1 4160 V Subsystem and 3.8.1 3.8.7 CT Same as Current U2 TS Entries The loss of a subsequent Unit 1 4160 V a subsequent Unit 14160 V A3 72 hr subsystem (either the same or other Subsystem de-energized on B4 72 hr division) requires entry into LCO 3.8.1 either the same or other 1 and the exception in Note 3 is no longer Division D2 12 hr applicable. Entry into LCO 3.0.3 is C1 72 hr required because this Condition is either GI LCO 3.0.3. covered by Action G1 (other Division) or it is not covered by TS 3.8.1 (same Division).

Unit 1 4160 V Subsystem and 3.8.1 3.8.7 CT 3.8.7 CT The loss of a subsequent Unit 2 4160 V a subsequent Unit 2 4160 V A3 72 hr Cl 72 hr subsystem does not necessarily result in Subsystem (energized but B4 72 hr Al 8 hr the loss of an offsite source which inoperable) DI D2 12 hr requires entry into LCO 3.8.1 if the Unit D hr D 1, 72 2 bus remains energized but inoperable.

Cl 72 hr Note 3 still applies. LCO 3.8.7 Action Al 8 hr A.I establishes the 8 hr completion time.

Unit 1 4160 V Subsystem and 3.8A1 3.8.7 CT 3.8.7 CT The loss of a subsequent Unit 1 4160 V a subsequent Unit 1 4160 V- A3 72 hr C1 72 hr subsystem (either the same or other Subsystem either same or 72 hr LCO 3.0.3 division) does not necessarily result in other Division (energized but the loss of an offsite source which inoperable) D2 12 hr requires entry into LCO 3.8.1 if the bus C1 72 hr remains energized but inoperable. Note 3 GI LCO 3.0.3 still applies. Entry into LCO 3.0.3 is required because this Condition is not covered by TS..

The above table demonstrates that, except for the condition which the proposed new ACTIONS Note 3 is intended to address (i.e. a Unit 1 4160 V subsystem de-energized to perform bus maintenance), the proposed LCO Conditions that would be entered and Required ACTIONS are not less restrictive than the current TS LCO Conditions and Required ACTIONS.

When new ACTIONS Note 3 is applicable, the three power supplies to the bus, i.e., the offsite primary and alternate supplies which are connected through the startup transformers and the DG associated with the affected bus, remain OPERABLE and capable of supplying power to the loads connected to the remaining seven 4160 V buses.

In this configuration, Note 3 requires immediate entry into LCO 3.8.7 , "Distribution Systems - Operating" Condition C. A loss of Safety Function Evaluation is required by LCO 3.0.6 and performed to support entry into this condition. If any other required supported equipment becomes inoperable, the safety function determination program.

would be implemented and would assure the appropriate conditions and Required ACTIONS would be taken.

Since a Unit 1 4160 V bus outage does not prevent any DG from connecting to its associated Unit 2 AC distribution subsystem, if a design basis loss of coolant accident (LOCA) and loss of offsite power occur on Unit 2 during performance of the Unit 1 bus outage, the DG would start and load as necessary to provide AC power to the necessary loads to mitigate the accident.

Enclosure to PLA-6148 Page 8 of 12 If a loss of offsite power event alone were to occur to one or both units during the Unit 1 4160 V bus outage, all remaining AC distribution subsystems not associated with the inoperable subsystem remain capable of supporting the minimum safety functions necessary to shutdown the reactor(s) and maintain them in a safe shutdown condition based on receiving power from the four DGs.

5. REGULATORY SAFETY ANALYSIS 5.1 No Significant Hazards Consideration This "No Significant Hazards Consideration" evaluates the following change to the Technical Specifications:.

A new ACTIONS Note 3 is added to the Unit 2 Technical Specification 3.8.1 to allow a Unit 1 4160 V subsystem to be de-energized and removed from service to perform bus maintenance.

1. Do the proposed changes involve a significant increase in the probability or consequences of an accident previously evaluated?

Response: No This change does not involve any physical change to structures, systems, or components (SSCs) and does not alter the method of operation of any SSCs. The current assumptions in the safety analysis regarding accident initiators and mitigation of accidents are unaffected by these changes. No SSC failure modes or mechanisms are being introduced, and the likelihood of previously analyzed failures remains unchanged.

Operation in accordance with the proposed new ACTIONS Note 3 in Unit 2 Technical Specification 3.8.1 ensures that the AC distribution system and supported equipment remain capable of performing their functions as described in the Final Safety Analysis Report (FSAR). There are no changes to any accident initiators or to the mitigating capability of safety-related equipment supported by the Class 1E Electrical AC system. The protection provided by these safety-related systems will continue to be provided as assumed by the safety analysis.

Therefore, this proposed change does not involve a significant increase in the probability or consequences of an accident previously evaluated.

Enclosure to PLA-6148 Page 9 of 12

2. Do the proposed changes create the possibility of a new or different kind of accident from any accident previously evaluated?

Response: No The proposed change does not involve a physical alteration of any plant equipment. No new equipment is being introduced, and installed equipment is not being operated in a new or different manner. There are no setpoints, at which protective or mitigative actions are initiated, affected by this change. This change does not alter the manner in which equipment operation is initiated, nor will the function demands on credited equipment be changed. No alterations in the procedures that ensure the plant remains within analyzed limits are being proposed, and no changes are being made to the procedures relied upon to respond to an off-normal event as described in the FSAR. As such, no new failure modes are being introduced. The change does not alter assumptions made in the safety analysis and licensing basis.

Therefore, the proposed change does not create the possibility of a new or different kind of accident from any previously evaluated.

3. Do the proposed changes involve a significant reduction in a margin of safety?

Response: No The margin of safety is established through equipment design, operating parameters, and the setpoints at which automatic actions are initiated. The proposed change is acceptable because the new ACTIONS Note 3 has been established to be consistent with the existing completion times for declaring required equipment inoperable that has no offsite power or DG power available.

Therefore, the plant response to analyzed events is not affected by this change and will continue to provide the margin of safety assumed by the safety analysis.

Therefore, the proposed change does not involve a significant reduction in a margin of safety.

Based on the above, PPL concludes that the proposed changes do not involve a significant hazards consideration under the standards set forth in 10 CFR 50.92(c),

and accordingly, a finding of no significant hazards consideration is justified.

Enclosure to PLA-6148 Page 10 of 12 5.2 Applicable Regulatory Requirements/Criteria SSESTFSAR Sections 3.1 and 3.13 provide detailed discussion of SSES compliance with the applicable regulatory requirements and guidance.

The proposed TS amendment:

(a) Does not alter the design or function of any system; (b) Does not result in any change in the qualifications of any component; and (c) Does not result in the reclassification of any component's status in the areas of shared, safety-related, independent, redundant, and physically or electrically separated.

Susquehanna conformance with the applicable General Design Criteria (GDC) related to the proposed Unit 2 TS 3.8.1 change is provided as follows:

GDC 5 - Sharingof Structures, Systems and Components Offsite power supplies - The two preferred offsite power supplies are shared by both units 1 and 2. The capacity of each offsite power supply is sufficient to operate the Engineered Safety Features (ESF) of one unit and safe shutdown of the other unit. Additional details are provided in FSAR Section 8.2.

Diesel Generators - The Diesel Generators are shared systems important to safety. Loss of one of the four aligned diesel generators will not impair the capability to safely shutdown both units, since this can be done with three diesel generators. Additional details are provided in FSAR Section 8.3.1.4.

Unit 1 AC Distribution System - The Unit 1 AC Distribution system is a shared system between both units 1 and 2 since the common equipment (Emergency Service Water, Standby Gas Treatment System, Control Structure HVAC, and Control Room Floor Cooling) is energized only from the Unit 1 AC Distribution System. The capacity of the Unit 1 AC Distribution System is sufficient to operate the engineered safety features.

on one unit and the safe shutdown loads of the other unit.

GDC 17 - ElectricPower Systems Two offsite power transmission systems and four onsite standby diesel generators (A, B, C and D) with their associated battery systems are provided. Either of the two offsite transmission power systems or any three of the four onsite standby diesel generator systems have sufficient

Enclosure to PLA-6148 Page 11 of 12 capability to operate safety related equipment for cooling the reactor core and maintaining primary containment integrity and other vital functions in the event of a postulated accident in one unit with a safe shutdown of the other unit.

Additionally, a fifth diesel generator 'E' with its associated battery system is provided as a replacement, and has the capability of supplying the emergency loading for any one of the other four diesel generators (A, B, C or D). Diesel generator 'E' must be manually aligned to replace any one of the other four diesel generators in the event of a failure.

The two independent offsite power systems supply electric power to the onsite power distribution system via the 230 kV transmission grid. Each of the offsite power sources is supplied from a transmission line which terminates in switchyards (or Substations) not common to the other transmission line. The two transmission lines are on separate rights-of-way. These two transmission circuits are physically independent and are designed to minimize the possibility of their simultaneous failure under operating and postulated accident and environment conditions.

Each offsite power source can supply all Engineered Safety Feature (ESF) buses through the associated transformers. Power is available to the ESF buses from their preferred offsite power source during normal operation and from the alternate offsite power source if the preferred power is unavailable. Each diesel generator (A, B, C, or D) supplies standby power to one of the four ESF buses in each unit. Loss of both offsite power sources to an ESF bus results in automatic starting and connection of the associated diesel generator (A, B, C, or D) within 10 seconds. Loads are progressively and sequentially added to avoid generator instabilities.

There are four independent AC load groups provided to assure independence and redundancy of equipment function. These meet the safety requirements assuming a single failure since any three of the four load groups have sufficient capacity to supply the minimum loads required to safely shut down the unit. Independent routing of the preferred and alternate offsite power source circuits to the ESF buses are provided to meet the single failure safety requirements.

Additional discussion and details are provided in FSAR Sections 8.2 and 8.3.

Enclosure to PLA-6148 Page 12 of 12 Based on compliance with the General Design Criteria 5 and 17 above, (1) there is reasonable assurance that the health and safety of the public will not be endangered by operation in the proposed manner, (2) such activities will be conducted in compliance with the Commission's regulations, and (3) the issuance of the amendment will not be inimical to the. common defense and security or to the health and safety of the public.

6. ENVIRONMENTAL CONSIDERATION 10 CFR 51.22(c)(9) identifies certain licensing and regulatory actions, which are eligible for categorical exclusion from the requirement to perform an environmental assessment.

A proposed amendment to an operating license for a facility does not require an environmental assessment if operation of the facility in accordance with the proposed amendment would not: (1) involve a significant hazards consideration; (2) result in a significant change in the types or significant increase in the amounts of any effluents that may be released offsite; or (3) result in a significant increase in individual or cumulative occupational radiation exposure. PPL Susquehanna, LLC has evaluated the proposed change and has determined that the proposed change meets the eligibility criteria for categorical exclusion set forth in 10 CFR 51 .22(c)(9). Accordingly, pursuant to 10 CFR 51.22(b), no environmental impact statement or environmental assessment needs to be prepared in connection with issuance of the amendment. The basis for this determination, using the above criteria, follows:

Basis As demonstrated in the "No Significant Hazards Consideration" evaluation, the proposed amendment does not involve a significant hazards consideration.

There is no significant change in the types or significant increase in the amounts of any effluents that may be released offsite. The proposed change does not involve any physical alteration of the plant (no new or different type of equipment will be installed) or change in methods governing normal plant operation.

There is no significant increase in individual or cumulative occupational radiation exposure. The proposed change does not involve any physical alteration of the plant (no new or different type of equipment will be installed) or change in methods governing normal plant operation.

7. REFERENCES FSAR Sections 3.1, 3.13, 8.1, 8.2 and 8.3

Attachment 1 to PLA-6148 PPL Susquehanna, LLC Proposed Change to Unit 2 Technical Specification 3.8.1 "Electrical Power Systems -

AC Sources Operating" (Markups)

PPL Rev.

AC Sources-Operating 3.8.1 3.8 ELECTRICAL POWER SYSTEMS 3.8.1 AC Sources-Operating LCO 3.8.1 The following AC electrical power sources shall be OPERABLE:

a. Two qualified circuits between the offsite transmission network and the onsite Class 1 E AC Electrical Power Distribution System; and
b. Four diesel generators (DGs).
c. Two qualified circuits between the offsite transmission network and the Unit 1 onsite Class 1 E AC electrical power distribution subsystem(s) required by LCO 3.8.7, Distribution Systems-Operating; and
d. The DG(s) capable of supplying the Unit 1 onsite Class 1 E electrical power distribution subsystem(s) required by LCO 3.8.7.

APPLICABILITY: MODES 1, 2, and 3.

ACTIONS

NOTES -------------------------------

1. LCO 3.0.4.b is not applicable to DGs.
2. When an OPERABLE diesel generator is placed in an inoperable status solely for the purpose of alignment of DG E to or from the Class 1 E distribution system, entry into associated Conditions and Required Actions may be delayed for up to 8 hours9.259259e-5 days <br />0.00222 hours <br />1.322751e-5 weeks <br />3.044e-6 months <br />, provided both offsite circuits are OPERABLE and capable of supplying the affected 4.16 kV ESS Bus.
3. When Unit 1 is in Modes 4 or 5 and an OPERABLE Unit 1 4160 V subsystem is placed in an inoperable status solely for the purpose of performinq bus maintenance with both offsite circuits and four diesel generators otherwise OPERABLE, only entry into LCO 3.8.7 Condition C is reauired.

CONDITION REQUIRED ACTION COMPLETION TIME A. One offsite circuit A.1 Perform SR 3.8.1.1 for 1 hour1.157407e-5 days <br />2.777778e-4 hours <br />1.653439e-6 weeks <br />3.805e-7 months <br /> inoperable. OPERABLE offsite circuit.

AND Once per 8 hours9.259259e-5 days <br />0.00222 hours <br />1.322751e-5 weeks <br />3.044e-6 months <br /> AND thereafter (continued)

SUSQUEHANNA - UNIT 2 TS / 3.8-1 Amendment Ilk 17"51

Attachment 2 to PLA-6148 PPL Susquehanna, LLC Proposed Change to Unit 2 Technical Specification Bases 3.8.1 "Electrical Power Systems -

AC Sources Operating" (Markups provided for Information Only)

PPL Rev. 4 AC Sources-Operating B 3.8.1 BASES LCO capable of supplying the required loads. If no OPERABLE offsite (continued) circuit is capable of supplying any of the 4.16 kV ESS Buses, provided that the offsite circuits otherwise meet the above requirements, one offsite source shall be declared inoperable. Unit 2 also requires Unit 1 offsite circuits to be OPERABLE.

If a Unit 1 4.16 kV bus is de-energized solely for the purpose of performing maintenance, it is not required to declare an offsite source or diesel generator inoperable.

Four of the five DGs are required to be Operable to satisfy the initial assumptions of the accident analyses. Each required DG must be capable of starting, accelerating to rated speed and voltage, and connecting to its respective ESS bus on detection of bus undervoltage after the normal and alternate supply breakers open.

This sequence must be accomplished within 10 seconds. If a Unit 1 4.16 kV bus is isolated from its DG solely for the performance of bus maintenance, the DG is not required to be declared inoperable.

Each DG must also be capable of accepting required loads within the assumed loading sequence intervals, and must continue to operate until offsite power can be restored to the ESS buses. These capabilities are required to be met from a variety of initial conditions, such as DG in standby with the engine hot and DG in normal standby conditions. Normal standby conditions for a DG mean that the diesel engine oil is being continuously circulated and engine coolant is circulated as necessary to maintain temperature consistent with manufacturer recommendations. Additional DG capabilities must be demonstrated to meet required Surveillances, e.g., capability of the DG to revert to standby status on an ECCS signal while operating in parallel test mode.

Although not normally aligned as a required DG, DG E is normally maintained OPERABLE (i.e., Surveillance Testing completed) so that it can be used as a substitute for any one of the four DGs A, B, C or D.

Proper sequencing of loads, including tripping of nonessential loads, is a required function for DG OPERABILITY.

The AC sources must be separate and independent (to the extent possible) of other AC sources. For the DGs, the separation and independence are complete. For the offsite AC sources, the separation and independence are to the extent practical. A circuit may be connected to more than one ESS bus, with automatic transfer capability to the other circuit OPERABLE, and not violate separation criteria. A circuit that is not connected to an ESS bus is required to (continued)

SUSQUEHANNA - UNIT 2 TS / B 3.8-5 Revision

PPL Rev. 4 AC Sources-Operating B 3.8.1 BASES LCO have OPERABLE automatic transfer interlock mechanisms to each (continued) ESS bus to support OPERABILITY of that offsite circuit. If a Unit 1 -

4.16 kV bus is de-energized solely for the purpose of performing maintenance, automatic transfer interlock mechanisms for the de-energized bus are not required to be operable.

APPLICABILITY The AC sources are required to be OPERABLE in MODES 1, 2, and 3 to ensure that:

a. Acceptable fuel design limits and reactor coolant pressure boundary limits are not exceeded as a result of AOOs or abnormal transients; and
b. Adequate core cooling is provided and containment OPERABILITY and other vital functions are maintained in the event of a postulated DBA.

The AC power requirements for MODES 4 and 5 are covered in LCO 3.8.2, "AC Sources-Shutdown."

ACTIONS A Note prohibits the application of LCO 3.0.4.b to an inoperable DG.

There is an increased risk associated with entering a MODE or other specified condition in the Applicability with an inoperable DG and the provisions of LCO 3.0.4.b, which allow entry into a MODE or other specified condition in the Applicability with the LCO not met after performance of a risk assessment addressing inoperable systems and components, should not be applied in this circumstance.

The ACTIONS are modified by a Note, which allows entry into associated Conditions and Required Actions to be delayed for up to 8 hours9.259259e-5 days <br />0.00222 hours <br />1.322751e-5 weeks <br />3.044e-6 months <br /> when an OPERABLE diesel generator is placed in an inoperable status for the alignment of diesel generator E to or from the Class 1E distribution system. Use of this allowance requires both offsite circuits to be OPERABLE. Entry into the appropriate Conditions and Required Actions shall be made immediately upon the determination that substitution of a required diesel generator will not or can not be completed.

Note 3 modifies the ACTIONS by allowing a Unit 1 4160 V subsystem (4.16 kV bus) to be de-energized for bus maintenance when Unit 1 is in Modes 4 or 5 and Unit 2 is in Modes 1,2, or 3 without requiring either offsite circuit or the associated diesel generator to be declared inoperable. Only entry into LCO 3.8.7 Condition C is required for this maintenance activity. While in this configuration, immediate entry into LCO 3.8.1 is required for any offsite circuit or DG that becomes inoperable. Note 3 then no longer applies.

(continued)

SUSQUEHANNA - UNIT 2 TS / B 3.8-6 Revision

PPL Rev. 4 AC Sources-Operating B 3.8.1 BASES ACTIONS A. 1 (continued)

To ensure a highly reliable power source remains with one offsite circuit inoperable, it is necessary to verify the availability of the remaining required offsite circuit on a more frequent basis. Since the Required Action only specifies "perform," a failure of SR 3.8.1.1 acceptance criteria does not result in a Required Action not met. However, if a second required circuit fails SR 3.8.1.1, the second offsite circuit is inoperable, and Condition C, for two offsite circuits inoperable, is entered.

SUSQUEHANNA - UNIT 2 TS / B 3.8-6a Revision

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