ML071710427

Summary of June 13, 2007, Category 1 Working -Level Meeting with PPL to Discuss the Licensee'S Proposed License Amendment Request Regarding Electrical Distribution Systems Dated March 2, 2007 ADAMS Accession No. ML070720545

ML071710427
Person / Time
Site:	Susquehanna
Issue date:	06/13/2007
From:	NRC/NRR/ADRO/DORL/LPLA
To:
Guzman R, NRR/DORL, 415-1030
References
Download: ML071710427 (14)

Text

NRC I PPL Meeting June 13, 2007 Proposed Change to Susquehanna Unit 2 Technical Specification 3.8.1 for a Unit 1 -4.16 kV Bus Out of Service to Perform Routine Maintenance NRC Headquarters Agenda" Introduction

• Description of SSES Electrical System* Discussion of Proposed TS Change" Conclusions 1

" License Amendment Request submitted March 2, 2007 (via PLA-6148)" Requested approval for proposed change to Unit 2 TS 3.8.1* Change is necessary to support the 4.16 kV Bus maintenance during the Unit 1 Refueling Outage in 2008.SSES Unit 2 Technical Specification 3.8.1 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 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;

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 3.2 SSES Unit 2 Technical Specification 3.8.1 Per TS 3.8.1 Bases: Offsite Circuit -All breakers, transformers, switches, automatic tap changers, interrupting devices, cabling, and controls required to transmit power from the offsite transmission network to the onsite Class IE ESS bus or busses.OPERABLE Offsite Circuit -exists when the startup transformer is energized and load tap changer in automatic operation, AND when a circuit path exists between transformers and feeder breakers that is capable of supplying three of four 4.16 kV buses, AND when acceptable grid voltage conditions exist.SSES Unit 2 Technical Specification 3.8.1 Per TS 3.8.1 Bases: Both offsite circuits are OPERABLE -provided each meets the criteria for an OPERABLE Offsite Circuit and provided that no 4.16 kV bus has less than one OPERABLE offsite circuit capable of supplying the required loads.If no OPERABLE offsite circuit is capable of supplying any of the 4.16 kV ESS Buses, one offsite source shall be declared inoperable.

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.3 SSES Unit 2 Technical Specification 3.8.1 3.8.1 -AC Sources Operating Condition A: One offsite circuit inoperable Condition B: One required DG inoperable Condition D: One offsite circuit inoperable AND One required DG inoperable.

Required Action for Condition D is to restore an offsite circuit to OPERABLE status within 12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br /> or restore the required DG to OPERABLE status within 12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br />.SUNBURY #2 WESCOSVILLE SSES OFFSITE CIRCUITS MTONTOUR STAENTNS$T0NTONBUR I JANKOIN L J SUNBURY IHARWvOOD I 500 kV/230 kV TIE LINE + E. PALMERT 105 I R1010 ....... ,-ON MO-UNT I UR rIN 2R (MO TE2-t-II 2R1OK HSGS)230 KV 13 8 KV 04/ BUS 5 SIU2BUS MAIN TRANS TRANS 230KV 230KV IR105 500KV 2X101.B C 24 KV 24 KV MOAB 24-KV 2I01A-B. 1R06 2 3 PHASES) 1[ SGS I ISOPHASE GEN 20101 ISOPHASE 1S101 230 Ky4Y S4KV 2X002KV 55 13.5 EV TRANS T-10 13.K UNITAUX 13 KV UNITAUX 0X10.TRANS 7-12 TRANS T-11 AUX BUS 0 UX 1U2 AUX I UK .A S S1 0U.12A 01 ) 12. '1J)1 1) 1A 10 ;01 TI[Ft ,? US' 00001 'I -E BLRu ES501 20 38V 0. SB 10 X TRAN 0 8 AN BU 4k 38KVe 13S0K 2021 1S211 3 03 04 04 0 04 1......~E7'- 2A0 250 issnos [ / i6S1 UNIT OPERATIONAL Al OGSC LINEUP SH0O2LN OA X 0 TIE...BU.S..

... ... ... ... ..X 4 SUNBURY 02 1 _TANTON#21 STANTON 0l WECOSVIL.EI 4.16 kV Bus NORMAL POWER SUPPLIES via T-10 TANTOUR JENKTNS SUNBURY I HARWO2OD-- E PALMERTON 5000 kVr23O kV TIE LINE VME.PALMURO T2R105 IHSGS 500KV NOA (MOAB) wy IX102 lX101 MAIN 1ýýaT MIN SRAN.TRANS 230KV 230KVA0 1R105 S HSGS 500KV 2210 24 KV 21 4 KV MOAB§77 2X10MB.C 3 HSSl 1 RI05 TS/U "-j20KV 3 HASE HSGS )10504 04 V0 T2EI US 03 TRANS T-12 24KVKr, US~ ~ 0050 8 __AU 2A 01 5010 CAT 11A Rc oTW8UIT o RIAT OAUX 06) 1101 TWO X502 TIOP5 RATO A AUXNEU SHOKV.8 SUNBURY6 I3 I / NTON_ _WESCOSVILLE 4.16 kV Bus NORMAL POWER SUPPLIES via T-20 STANTONR 2 STANTON1 MONTOUR IJENKINS SUN.URY A HW 0 E. PALMERTON 500 V/230 kV TIE LINE MOTOR 2R105T (MOAIý V 1I102 I101 MAJ--0KHSGS) K MOAB S/i K~V 13,, PHASES) SS tl(HSOS)RAINS AS E Lo TIBS 03 T 3 ISOPKASE 2GE01 ISOPHASE lG10S T.2 2230KV 0X104 4KV 2 5 2KV13 8 KV TRAN T-10 13 8 K UNITAUX 13.KV UNIT AUX 0X103 1 0 0TRANS T-12 ;2 0TRANS T-11 u AU BUS AUX ..S AUA UU AU. .SX SU.2 0 00211 1"130 KV 04 04N AD US130 O EVSSIll II 1 501 A X 0-4 0404 .i0. OPEN RE3 13 8 KV CT10K T20G1S1C TW UNIT OPERATIONAL ESS20UP SHO6-KV 5

-2 I4 kV Bus- Alternate Power Supplies 1 13.8 KV 13.8 KV 6 4 kV Bus -D/G Power Supplies I Why does Unit I -4.16 kV Bus maintenance affect operation of Unit 2?7 COMMON LOADS The Unit 2 Safety Analysis assumes the OPERABILITY of some equipment receiving power from the Unit 1 AC Sources. Unit 2 TS establish the requirements for OPERABILITY of the DG(s) and qualified offsite circuits needed to support the Unit 1 onsite Class 1 E AC electrical power distribution subsystem(s) required by LCO 3.8.7, Distribution Systems -Operating.

8 ESS Bus IA (1A201)RHR Pump 1A Core Spray Pump 1A ESW Pump A ESS Load Center 1B210 CRD Pump 1A Rx Bldg Chiller 1A Turb Bldg Chiller 1A ESS Bus 2A (2A201)RHR Pump 2A Core Spray Pump 2A ESS Load Center 2B210 CRD Pump 2A RHR SW Pump 2A Turb Bldg Chiller 2A The load Identified in Red is a "Common Load" ESS Bus 1B (1A202)ESS Bus 2B (2A202)RHR Pump 1B Core Spray Pump 1 B ESW Pump B ESS Load Center 1B220 Mech Vacuum Pump Rx Bldg Chiller 1 B Turb Bldg Chiller 1 B RHR Pump 2B Core Spray Pump 2B ESS Load Center 2B220 RHR SW Pump 2B Rx Bldg Chiller 2B The load Identified in Red is a "Common Load" 9 ESS Bus IC (1A203)RHR Pump 1C Core Spray Pump 1C ESW Pump C ESS Load Center 1B230" RHR SW Pump 1A Control Structure Chiller A ESS Bus 2C (2A203)RHR Pump 2C Core Spray Pump 2C ESS Load Center 2B230 Mech Vacuum Pump Rx...Bldg...Chiller....=2A.

Rx Bldg Chiller 2A Loads Identified in Red are "Common Loads" 480 V Common Load Power Supply (SGTS, CR Floor Cooling, CREOAS)ESS Bus 1D (1A204)RHR Pump 1D Core Spray Pump 1D ESW Pump D ESS Load Center 1B240*CRD Pump 1B RHR SW Pump 1B Cont Structure Chiller 1B ESS Bus 2D (2A204)RHR Pump 2D Core Spray Pump 2D ESS Load Center 2B240 CRD Pump 2B Rx Bldg Chiller 2B Loads Identified in Red are "Common Loads"*480 V Common Load Power Supply (SGTS, CR Floor.Cooling, CREOAS)10 Issue: The existing Unit 2 TS 3.8.1 requires that when a Unit 1 4.16 kV ESS bus is de-energized for routine maintenance, LCO 3.8.1 Conditions A, B, and D are entered. An offsite circuit (Condition A) and a DG (Condition B) are declared inoperable thus, TS 3.8.1 Condition D requires a 12 hour1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br /> Completion Time to perform all the maintenance work on the bus.The time required to perform all the scheduled bus maintenance is between 50 and 60 hours6.944444e-4 days <br />0.0167 hours <br />9.920635e-5 weeks <br />2.283e-5 months <br />. (Details of the work evolution and necessary LCO's are provided in the submittal.)

Proposed Resolution:

Add a note to Unit 2 TS 3.8.1 which effectively removes the requirement for entry into the TS and thus the associated actions A, B, and D. Text of the note is: 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 performing bus maintenance with both offsite circuits and four required diesel generators otherwise OPERABLE, only entry into LCO 3.8.7 Condition C is required.11 The note will only be applicable when a 4.16 kV bus is removed from service for maintenance as shown in the following example (Unit 1 -4.16 kV Bus 1A)12 Conclusions

• Inclusion of the proposed note to Unit 2 TS 3.8.1 does not require either offsite power supply nor Diesel Generator A (for example) to be declared inoperable per TS 3.8.1. As shown in the previous figure, both offsite power supplies and 4 required diesel generators remain capable of supplying seven (7) of the eight (8) 4.16 kV buses in both units.* Only entry into Unit 2 LCO 3.8.7 is required which establishes the completion time associated with a Unit 1 bus out of service, as discussed in the submittal." All other ESS bus equipment "out of service" scenarios, due to other maintenance (i.e. feeder breaker, transformer, etc.) result in the entry of both TS's 3.8.1 and 3.8.7. Each of these plant equipment configurations is discussed in the submittal along with the appropriate TS completion time for each configuration.

Since LCO 3.8.7 Condition C is the only affected TS LCO condition after application of the new note to LCO 3.8.1, the 72 hour8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br /> completion time is applicable.

Thus sufficient time is provided to perform the necessary 4.16 kV bus maintenance.

Adding this note to Unit 2 TS 3.8.1 precludes the need to enter any LCO 3.8.1 conditions for this very narrowly defined Unit 1 4.16 kV bus configuration.

13 Questions?

14