PLA-5895, Exigent Change to Technical Specification 3.8.4

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Exigent Change to Technical Specification 3.8.4
ML051370375
Person / Time
Site: Susquehanna  Talen Energy icon.png
Issue date: 05/04/2005
From: Saccone R
Susquehanna
To:
Document Control Desk, Office of Nuclear Reactor Regulation
References
PLA-5895
Download: ML051370375 (13)
v • d • e


Text

Robert A. Saccone Vice President-Nuclear Operations PPL Susquehanna, LLC 769 Salem Boulevard Berwick, PA 18603 Tel. 570.542.3959 Fax 570.542.1504 rasaccone@pplweb.com I

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MY 0 4 an U. S. Nuclear Regulatory Commission Attn: Document Control Desk Mail Stop OP1-17 Washington, DC 20555 SUSQUEHANNA STEAM ELECTRIC STATION PROPOSED AMENDMENT NO. 275 TO UNIT 1 FACILITY OPERATING LICENSE NPF-14 AND PROPOSED AMENDMENT NO. 244 TO UNIT 2 FACILITY OPERATING LICENSE NPF-22: EXIGENT CHANGE TO TECHNICAL SPECIFICATION 3.8.4 PLA-5895 Docket Nos. 50-387 and 50-388

Reference:

PLA-5891, B. T. McKinnley (PPL) to Documnent Control Desk (USNRC),

"Proposed Ameendment No. 275 to Unit 1 Facility Operating License NPF-14 and Proposed Amendment No. 244 to Unit 2 Facility Operating License NPF-22 Exigent Change to Technical Specification 3.8.4, " dated April 27, 2005.

In accordance with the provisions of 10 CFR 50.90, PPL Susquehanna, LLC submitted a request for amendment to the Technical Specifications for Susquehanna Unit 1 and Unit 2 (Reference 1).

In accordance with the provisions of 10 CFR 50.91 (a)(6), PPL Susquehanna, LLC requested this amendment be processed on an exigent basis.

This letter is provided to clarify two sections of the Reference I submittal based on teleconferences held April 28 and April 29 between PPL and NRC.

The enclosure to this letter contains the revised Section 4.0 "Technical Safety Analysis of the Proposed Changes" and revised Section 5.1 "No Significant Hazards Consideration."

Any questions regarding this request should be directed to Mr. Duane L. Filchner at (610) 774-7819.

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Document Control Desk Document Control Desk PLA-5895 I declare under penalty of perjury that the foregoing is true and correct.

Executed on:

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R.

/cacone Enclosure - Revised Sections 4.0 and 5.1 cc:

NRC Region I Mr. A. J. Blarney, NRC Sr. Resident Inspector Mr. R. V. Guzman, NRC Project Manager Mr. R. Janati, DEP/BRP

ENCLOSURE TO PLA-5895 Revised Sections 4.0 and 5.1

Enclosure to PLA 5895 Page 1 of 10 4.0 TECHNICAL SAFETY ANALYSIS OF THE PROPOSED CHANGES These changes add specific actions and increased completion times for an electrical power subsystem that has been taken out of service for performance of special inspection and related activities on a 125 VDC subsystem's battery charger.

The Technical Specification restoration time for an inoperable battery charger is limited to the same time as for an inoperable battery or a completely de-energized DC distribution subsystem, i.e., 2 hours2.314815e-5 days <br />5.555556e-4 hours <br />3.306878e-6 weeks <br />7.61e-7 months <br />. The primary role of the battery charger is in support of maintaining operability of its associated battery. This is accomplished by the charger being of sufficient size to carry the normal steady state DC loads, with sufficient additional capacity to maintain the battery fully charged. The current 2-hour restoration time is based on Regulatory Guide 1.93, "Availability of Electric Power Sources," and has been applied equally to a minimal reduction in battery charger capacity.

The proposed changes provide an increased restoration time that is of sufficient duration to support the special inspection and related activities. To compensate for the longer time, a portable battery charger will be connected to maintain the battery fully charged and capable of serving all the loads from its distribution panel. The changes are based on the use of a portable non Class lE 125 VDC battery charger, temporarily connected to each of the 125 VDC electrical power subsystems one at a time to perform special inspection and related activities on a permanently installed charger. Double electrical isolation will be provided for the portable charger.

It is acceptable for a non Class lE portable battery charger to be connected to the Class lE 125 VDC electric power subsystem while in LCO 3.8.4 because the battery is maintained fully charged and all connected Class lE loads remain operable. In the event of a Loss of Offsite Power (LOOP) or LOCA/LOOP Design Basis Accident (DBA), the portable battery charger is no longer capable of maintaining the battery fully charged. The 125 VDC loads connected to the battery is analyzed to be supplied by the battery according to its accident load profile, shown in FSAR Tables 8.3-6.

The following discussion provides a detailed description of the initial conditions and response of both Units 1 and 2 to a postulated DBA LOCA/LOOP while the portable battery charger is connected to one of the Unit 1 125 VDC electrical power subsystems:

Enclosure to PLA 5895 Page 2 of 10 Prior to the postulated DBA LOCA/LOOP on Unit 1

  • The proposed LCO 3.8.4 Condition A.2. is entered for the affected Class lE 125 VDC electrical power subsystem.
  • The Common 125 VDC loads on the affected subsystem (emergency diesel generators and controls, spray pond valves, breaker controls on the 4KV bus for offsite powerfrom TJO and offsitepowverfrom T20, the connected diesel generator output circuit breaker control, ESWpuinp circuit breaker control) and other Unit 1 loads on the affected subsystem, commonly known as "tag along loads" (RHR punip breaker, Core Spray pump breaker, the 480 volt load center supply breaker, RHRSWpunip breaker, and miscellaneous funlctions such as HVA C, plant auxiliary load shed, and RHR isolation logic) are transferred to the same lettered Unit 2 125 VDC Class IE electrical power subsystem prior to the Unit 1 Class lE battery charger being removed from service.
  • Unit 1 Post Accident mitigating systems whose 125 VDC power is not transferred to Unit 2 include HPCI (125 VDC Subsystem B), RCIC (125 VDC Subsystem A), and ADS (Div I and II). These high pressure systems are not required for a large break DBA LOCA because a high pressure condition is not present in the reactor. However, their operation would be required for a small break LOCA.

At T=0 a DBA LOCA/LOOP occurs on Unit 1 -

  • The four required common diesels start and supply the connected loads, which includes 3 out of 4 Class lE 125 VDC chargers on Unit 1 and 4 out of 4 Class IE chargers on Unit 2. The portable charger connected to one of the Unit 1 125 VDC electrical power subsystems becomes de-energized as a result of the LOOP.

At T > 4 hours4.62963e-5 days <br />0.00111 hours <br />6.613757e-6 weeks <br />1.522e-6 months <br />

  • The Unit 1 125 VDC loads that remain connected will complete their functions prior to the battery becoming discharged. These loads support accident initiation detection and isolation logic circuits.

Enclosure to PLA 5895 Page 3 of 10

  • The Unit 1 battery connected to the portable charger is assumed in the safety analysis to be able to supply the connected loads for 4 hours4.62963e-5 days <br />0.00111 hours <br />6.613757e-6 weeks <br />1.522e-6 months <br />. However, the actual discharge with the loads transferred to Unit 2 will result in the capability of the battery to supply the connected loads beyond 4 hours4.62963e-5 days <br />0.00111 hours <br />6.613757e-6 weeks <br />1.522e-6 months <br />.
  • Operation of the connected Unit 1 DC loads on the other 3 Class IE chargers is not affected because the diesels will provide the Class IE AC power supply to the chargers during the scenario.
  • The emergency diesel generators (including the diesel generator associated with the 125 VDC bus that had the portable charger connected as its 125 VDC source prior to the event) remain in operation supplying the connected loads.

Conclusions -

When the portable charger is connected to a Class 1E 125VDC electrical power subsystem on Unit 1, an LCO is entered for the affected subsystem per TS 3.8.4. In the event of a DBA LOCA/LOOP, three Unit 1 Class IE battery chargers and four Unit 2 Class lE battery chargers will remain in operation, receiving power from the diesel generators, to carry the required 125 VDC loads for the entire duration of the accident without discharging the batteries.

Therefore, 3 out of 4 Unit 1 batteries will remain fully charged for the duration of the accident, and 4 out of 4 batteries remain fully charged on Unit 2.

Per FSAR Section 8.3.2.2.1(a)(5) "Compliance with General Design Criteria 17, Electric Power Systems", sufficient capacity, capability, independence, redundancy, and testability are provided in the Class IE DC subsystems, ensuring the performance of safety functions assuming a single failure. Since the LCO is considered the single failure in this scenario, no additional failures are postulated. As a result of the description above, which includes common load transfer to Unit 2 on the subsystem removed from service, the actual impact on Unit 1 operation will be less severe than the DBA LOCA/LOOP condition evaluated in the safety analysis.

Only the Unit I battery that is connected to the portable charger will potentially discharge until it cannot supply its connected loads; this will occur over a minimum of 4 hours4.62963e-5 days <br />0.00111 hours <br />6.613757e-6 weeks <br />1.522e-6 months <br />. The accident mitigation capabilities of this battery are therefore available during the first 4 hours4.62963e-5 days <br />0.00111 hours <br />6.613757e-6 weeks <br />1.522e-6 months <br /> of the accident. However, the ability of the battery to supply the connected loads beyond 4 hours4.62963e-5 days <br />0.00111 hours <br />6.613757e-6 weeks <br />1.522e-6 months <br /> is reasonable when accounting for actual loads (less than design values) and the design margins (age and temperature correction) in the battery calculations.

Enclosure to PLA 5895 Page 4 of 10 The operation of the diesel generators and their ability to supply AC power until offsite power is restored remains unaffected because the DC control power for the diesel generator whose battery has been connected to the portable charger has been transferred to Unit 2. Additionally, other common 125 VDC loads have been transferred to Unit 2 and their operation is also unaffected by the eventual loss of the battery.

An evaluation of entry into proposed Unit 2 TS 3.8.4 Required Action A.2 to connect a portable battery charger for re-inspection of the Unit 2 125 VDC Class I E battery chargers produces a similar response to the Unit 1 DBA LOCA/LOOP scenario discussed above.

Prior to the postulated DBA LOCA/LOOP on Unit 2 -

  • The Common 125 VDC loads remain connected to the Unit 1 125 VDC electrical power subsystems.
  • The proposed LCO 3.8.4 Condition A.2 is entered for the affected Class IE 125 VDC electrical power subsystem.
  • The Operable Unit 2 Post Accident mitigating systems are those whose 125 VDC electrical power supplies not connected to the 125 VDC electrical power subsystem undergoing inspection. These systems will be sufficient and capable of mitigating the postulated DBA. The 125 VDC electrical power subsystem removed from service is the assumed single failure even though its battery remains available and is conservatively analyzed to provide at least the 4 hour4.62963e-5 days <br />0.00111 hours <br />6.613757e-6 weeks <br />1.522e-6 months <br /> accident profile in FSAR Table 8.3-6.

At T=0 a DBA LOCA/LOOP occurs on Unit 2 -

  • The four required common diesels start and supply the connected loads, which includes 4 out of 4 Class lE 125 VDC chargers on Unit 1 and 3 out of 4 Class l E chargers on Unit 2. The portable charger connected to one of the Unit 2 125 VDC electrical power subsystems becomes de-energized as a result of the LOOP.

Enclosure to PLA 5895 Page 5 of 10 At T> 4 hours4.62963e-5 days <br />0.00111 hours <br />6.613757e-6 weeks <br />1.522e-6 months <br />

  • The Unit 2 125 VDC loads connected to the 125 VDC electrical power subsystem that had been supplied by the portable charger will operate until the battery has discharged and cannot supply sufficient voltage to the loads.

Although the Unit 2 battery connected to the portable charger is assumed to be discharged beyond its capability to supply connected loads, the ability of the battery to supply the connected loads beyond 4 hours4.62963e-5 days <br />0.00111 hours <br />6.613757e-6 weeks <br />1.522e-6 months <br /> is reasonable when accounting for actual loads (less than design values) and the design margins (age and temperature correction) in the battery calculations.

  • Operation of the connected Unit 2 DC loads on the other 3 Class IE chargers is not affected because the diesels will provide the Class I E AC power supply to the chargers during the scenario.
  • The emergency diesel generators (including the diesel generator associated with the 125 VDC bus that had the portable charger connected as its 125 VDC source prior to the event) remain in operation supplying the connected loads.

Conclusions -

When the portable charger is connected to a Class lE 125 VDC electrical power subsystem on Unit 2, an LCO is entered for the affected sub-system per TS 3.8.4. Three Unit 2 Class lE battery chargers and four Unit 1 Class lE battery chargers will remain in operation, receiving power from the diesel generators, to carry the required 125 VDC loads for the entire duration of the accident without discharging the batteries. Therefore, 3 out of 4 Unit 2 batteries will remain fully charged for the duration of the accident, and 4 out of 4 batteries will remain fully charged on Unit 1.

Per FSAR Section 8.3.2.2.1(a)(5) "Compliance with General Design Criterial7, Electric Power Systems," sufficient capacity, capability, independence, redundancy, and testability are provided in the Class lE DC subsystems, ensuring the performance of safety functions assuming a single failure. Since the LCO is considered the single failure in this scenario, no additional failures are postulated.

  • Only the Unit 2 battery that is connected to the portable charger will potentially discharge until it cannot supply its connected loads; this will occur over a minimum of 4 hours4.62963e-5 days <br />0.00111 hours <br />6.613757e-6 weeks <br />1.522e-6 months <br />. The accident mitigation capabilities of this battery are therefore available during the first 4 hours4.62963e-5 days <br />0.00111 hours <br />6.613757e-6 weeks <br />1.522e-6 months <br /> of the accident. However, the

Enclosure to PLA 5895 Page 6 of 10 ability of the battery to supply the connected loads beyond 4 hours4.62963e-5 days <br />0.00111 hours <br />6.613757e-6 weeks <br />1.522e-6 months <br /> is reasonable when accounting for actual loads (less than design values) and the design margins (age and temperature correction) in the battery calculations.

The operation of the diesel generators and their ability to supply AC power until offsite power is restored remains unaffected because the DC control power for the diesel generator whose battery has been connected to the portable charger has remained on Unit 1.

Small Break LOCA -

RCIC and Division I of ADS are connected to the 125 VDC Subsystem A electrical power subsystem, HPCI and Division II of ADS are connected to the 125 VDC Subsystem B electrical power subsystem, and 125 VDC Subsystems C&D do not provide power to the high pressure injection systems. Should a small break LOCA occur while the portable charger is connected to one of the electrical power subsystems, HPCI, RCIC, and ADS will be powered until the subsystem relying on battery power becomes de-energized at greater than 4 hours4.62963e-5 days <br />0.00111 hours <br />6.613757e-6 weeks <br />1.522e-6 months <br /> after the event occurs. After 4 hours4.62963e-5 days <br />0.00111 hours <br />6.613757e-6 weeks <br />1.522e-6 months <br />, at least one high-pressure system (HPCI or RCIC) and one division of ADS are available for small break LOCA mitigation, depending upon which 125 VDC electrical power subsystem is taken out of service.

Impact of this change on other TS:

This change does not affect the 2-hour restoration time and actions for a DC electrical power subsystem that cannot meet the battery cell limits specified in TS 3.8.6.

The Category A and B limits reflect nominal fully charged battery parameter values. Significant margin above that required for declaration of an operable battery exists with the use of these values. These Category A and B values represent appropriate monitoring levels and an appropriate preventive maintenance level of long-term battery quality and extended battery life. These values do not reflect the 10 CFR 50.36, "Technical Specifications," criteria for LCOs of "the lowest functional capability or performance levels of equipment required for the safe operation of the facility."

Category C defines the limits for each connected cell. These values, although reduced, provide assurance that sufficient capacity exists to perform the intended function and maintain a margin of safety. When any battery parameter is outside

Enclosure to PLA 5895 Page 7 of 10 the Category C limits, the assurance of sufficient capacity no longer exists and the battery must be declared inoperable.

The proposed actions associated with an inoperable electrical power subsystem provide a tiered response that focuses on assuring the battery is charged, and the electrical power subsystem is restored to operable status. The first required Action A.2.1 is to perform SR 3.8.6.1 within 2 hours2.314815e-5 days <br />5.555556e-4 hours <br />3.306878e-6 weeks <br />7.61e-7 months <br /> to assure the battery is operable.

Maintaining the battery within the TS 3.8.6 limits ensures that the battery is in a high state of readiness and that the battery can fulfill its design basis function.

Proposed Required Action A.2.2 for Unit 1 and Unit 2 provides 36 hours4.166667e-4 days <br />0.01 hours <br />5.952381e-5 weeks <br />1.3698e-5 months <br /> to restore the inoperable electrical power subsystem to operable status. The 36 hour4.166667e-4 days <br />0.01 hours <br />5.952381e-5 weeks <br />1.3698e-5 months <br /> completion time represents a sufficient amount of time to perform the special inspection and related activities. This completion time is based on prior work completed on Unit 2, and includes additional time to transfer the common loads from Unit 1 to Unit 2, and perform the necessary post maintenance surveillances.

This work is expected to be completed within 18 hours2.083333e-4 days <br />0.005 hours <br />2.97619e-5 weeks <br />6.849e-6 months <br /> per battery charger; however, an additional 18 hours2.083333e-4 days <br />0.005 hours <br />2.97619e-5 weeks <br />6.849e-6 months <br /> per charger is requested as margin in the event unanticipated problems are encountered.

Risk assessments of the entire evolution will be performed to ensure plant configuration risk is fully understood and managed. Work Management actions will be taken to provide increased risk awareness and control, to minimize the duration of the activity, and to minimize the magnitude of the increase in plant risk in accordance with the PPL program and procedures that implement 10 CFR 50.65, "Maintenance Rule."

The specific Work Management actions include the following:

  • A plant procedure to control the maintenance evolution and battery charger restoration will be developed and implemented if necessary.
  • Once the LCO is entered, the work schedule will be around-the-clock.
  • An evolution coordinator will be on-site around-the-clock.
  • Engineering support personnel will be present around-the-clock.
  • The protected equipment program provides an awareness of those systems that will be utilized to compensate for the 125 VDC bus that will be impacted by the out-of-service charger. The program will not allow work on either unit on RPS, electrical switchyards that supply offsite power or transmit generator

Enclosure to PLA 5895 Page 8 of 10 output, Emergency Diesel Generators, Station Portable Diesel Generator, all Class IE AC & DC Electrical Systems, non-Class lE electrical systems that can cause a trip of either unit, HPCI, RCIC or ADS.

The Protected Equipment Program is a tool that ensures equipment and systems required to minimize the risk of core damage are identified and communicated to station personnel. The program also controls access and work within posted protected equipment boundaries by requiring station personnel to obtain authorization from the responsible Unit Supervisor prior to entering the area or working in the vicinity of the equipment, with the exception of On-Shift Operations, Firewatch, Security, Chemistry, and HP personnel, who will be fully briefed on the critical nature of the work.

  • The grid operator will not authorize any work activities at SSES that could cause a LOOP or main generator load reject.

In summary, this change is deemed acceptable because:

  • The primary role of the battery charger is in support of maintaining the associated battery.
  • The portable battery charger is of sufficient capacity to carry the normal steady-state loads while maintaining the battery fully charged; thus, it will be capable of maintaining operability of the associated battery.
  • The restoration time of 36 hours4.166667e-4 days <br />0.01 hours <br />5.952381e-5 weeks <br />1.3698e-5 months <br /> is sufficient to perform the needed special inspection and related activities
  • Risk management will be performed in accordance with PPL procedures.
  • The single failure requirements of GDC 17 remain satisfied for both SSES Unit 1 and Unit 2.

Enclosure to PLA 5895 Page 9 of 10 5.1 No Significant Hazards Consideration The Commission has provided standards in 10 CFR 50.92(c) for determining whether a significant hazards consideration exists. A proposed amendment to an operating license for a facility involves no significant hazards consideration if operation of the facility in accordance with the proposed amendment would not (1) involve a significant increase in the probability or consequences of an accident previously evaluated; (2) create the possibility of a new or different kind of accident from any accident previously evaluated; or (3) involve a significant reduction in a margin of safety.

PPL proposes changes to Appendix A, Technical Specifications (TS), of Facility Operating License Nos. NPF-14 and NPF-22 for the Susquehanna Steam Electric Station Units 1 and 2, respectively.

The proposed changes revise TS Section 3.8.4, "DC Sources - Operating," by revising the Condition A Required Actions for Unit 1 and Unit 2 with new actions and completion times for a electrical power subsystem that has been taken out of service to perform special inspection and related activities (defined as including any reasonably expected repairs) on the chargers.

In accordance with the criteria set forth in 10 CFR 50.92, PPL has evaluated the proposed TS change and determined it does not represent a significant hazards consideration. The following is provided in support of this conclusion.

1.

Does the proposed change involve a significant increase in the probability or consequences of an accident previously evaluated?

No. The proposed changes affect Technical Specification (TS) 3.8.4 for "DC Sources - Operating." The proposed changes add new Required Actions for Unit 1 and Unit 2 to specifically address a Class IE 125 VDC electrical power subsystem that has been taken out of service to perform special inspection and related activities. These changes rely upon the capability of providing the battery charger function by an alternate means (e.g., a 125 VDC portable battery charger) to justify the proposed completion times. The DC electrical power systems, including associated battery chargers, are not initiators to any accident sequence analyzed in the Final Safety Analysis Report (FSAR). Operation in accordance with the proposed TS ensures that the DC electrical power systems are capable of performing their functions as described in the FSAR. Therefore, the mitigative functions supported by the DC Power Systems will continue to provide the protection assumed by the analysis.

Enclosure to PLA 5895 Page 10 of 10 Based on the above, the proposed changes do not involve a significant increase in the probability or consequences of an accident previously evaluated.

2.

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

No. The proposed changes involve revising TS 3.8.4 "DC Sources -

Operating," for the DC electrical power systems. These changes rely upon the capability of providing the battery charger function by an alternate means to justify the proposed completion times when a normal battery charger is taken out of service to perform special inspections and related activities. The DC electrical power systems, which include the associated battery chargers, are not initiators to any accident sequence. Rather, the DC electrical power systems are used to supply equipment used to mitigate an accident. These mitigative functions, supported by the DC electrical power systems, provide the protection assumed by the safety analysis described in the FSAR. The portable battery charger will be connected to the Class IE 125 VDC subsystem using a double isolation method. Therefore, there are no new types of failures or new or different kinds of accidents or transients that could be created by these changes.

Based on the above, the proposed changes do not create the possibility of a new or different kind of accident from any accident previously evaluated.

3.

Does the proposed change involve a significant reduction in a margin of safety?

No. The margin of safety is established through equipment design, operating parameters, and the setpoints at which automatic actions are initiated. The proposed changes do not adversely affect operation of any plant equipment. These changes do not result in a change to the setpoints at which protective actions are initiated. Sufficient DC electrical system capacity is ensured to support operation of mitigation equipment. The equipment fed by the DC electrical sources will continue to be provided adequate power to safety-related loads in accordance with the safety analysis. Therefore, the proposed changes do not involve a significant reduction in a margin of safety.

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