DCL-06-126, Supplement to Exigent License Amendment Request 06-08 Revision to Technical Specification 3.8.4, DC Sources - Operating, Condition B
| ML063130349 | |
| Person / Time | |
|---|---|
| Site: | Diablo Canyon  |
| Issue date: | 11/02/2006 |
| From: | Becker J Pacific Gas & Electric Co |
| To: | Document Control Desk, Office of Nuclear Reactor Regulation |
| References | |
| DCL-06-126, OL-DPR-80 | |
| Download: ML063130349 (10) | |
Text
PacificGas and ElectricCompany James R. Becker Diablo Canyon Power Plant Vice President P. 0. Box 56 Diablo Canyon Operations and Avila Beach, CA 93424 Station Director 805.545.3462 November 2, 2006 Fax: 805.545.4234 PG&E Letter DCL-06-126 U.S. Nuclear Regulatory Commission ATTN: Document Control Desk Washington, D.C. 20555-0001 Docket No. 50-275, OL-DPR-80 Diablo Canyon Unit 1 Supplement to Exigent License Amendment Request 06-08 Revision to Technical Specification 3.8.4, "DC Sources - Operating.," Condition B
Reference:
- 1. PG&E Letter DCL-06-120, "Exigent License Amendment Request 06-08, Revision to Technical Specification 3.8.4,
'DC Sources - Operating,' Condition B," dated October 18, 2006 By letter dated October 18, 2006 (Reference 1), Pacific Gas and Electric Company (PG&E) submitted an exigent request for a one-time change to Technical Specification (TS) 3.8.4, Condition B, to extend the completion time (CT) for an inoperable vital battery from 2 hours2.314815e-5 days <br />5.555556e-4 hours <br />3.306878e-6 weeks <br />7.61e-7 months <br /> to 12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br />. The extended CT would allow sufficient time to correct a degraded condition affecting a single cell (Cell 15) that impacts the long-term reliability of Unit 1 Vital Battery 1-1 by either bypassing or replacing the battery cell.
In discussions with the NRC staff, PG&E agreed to limit the proposed CT to 4 hours4.62963e-5 days <br />0.00111 hours <br />6.613757e-6 weeks <br />1.522e-6 months <br />, which would allow only bypassing of Cell 15 without introducing time pressure as an error precursor. Revised TS and TS Bases pages reflecting this change are included in Enclosures 2 and 3.
In addition, the NRC staff identified additional information required to complete its review. PG&E's response to that request for information is included in Enclosure 1.
In Reference 1, PG&E stated that it would be prepared to either bypass or replace the Cell 15 upon issuance of the license amendment. That statement was based on potential further degradation of the cell. Following discovery of the Cell 15 degraded condition, PG&E implemented compensatory measures to install a single cell charger, and perform daily monitoring of Battery 1-1 and Cell 15 parameters. Daily monitoring since October 15, 2006, has shown that the Battery 1-1 and Cell 15 parameters have remained stable and within specification.
A A member of the Callaway
- Comanche Peak STARS (Strategic Diablo Canyon Teaming o Palo Verde and Resource Sharing)
- South Texas Project Alliance
- Wolf Creek A 0DI
Document Control Desk PG&E Letter DCL-06-126 November 2, 2006 Page 2 Since there is risk associated with removing a cell from service, and Battery 1-1 is currently operable, PG&E now intends to maintain the compensatory measures in place until the Unit I Fourteenth Refueling Outage (1 R14) scheduled to start in April 2007, at which time Cell 15 will be replaced. Should circumstances warrant taking corrective actions sooner than 1 R14, PG&E will bypass Cell 15 to support continued operability of Vital Battery 1-1.
The response provided in this submittal does not affect the results of the technical evaluation or the no significant hazards consideration determination previously transmitted in Reference 1.
PG&E makes no regulatory commitments (as defined by NEI 99-04) in this letter.
This letter includes no revisions to existing regulatory commitments.
If you have any questions or require additional information, please contact Stan Ketelsen at 805-545-4720.
I state under penalty of perjury that the foregoing is true and correct.
Executed on November 2, 2006.
Sincerely, James R. Becke Vice President - Diab o Canyon Operations and Station Director jer1 /3664 Enclosures cc: Edgar Bailey, DHS Terry W. Jackson Bruce S. Mallett Diablo Distribution cc/enc: Alan B. Wang A member of the STARS (Strategic Teaming and Resource Sharing) ALliance Cellaway
- Comanche Peak
- Diablo Canyon e Palo Verde
- South Texas Project
- Wolf Creek
Enclosure 1 PG&E Letter DCL-06-126 Response to Request for Additional Information NRC Question 1:
Describe the specific compensatory actions that will be taken priorto removing the battery from service (e.g., contact the Grid Operatorpriorto removing the battery from service; enact the protective train concept, etc.)
Pacific Gas and Electric Company (PG&E) Response:
In accordance with 10 CFR 50.65(a), PG&E will assess and manage the risk associated with taking Battery 1-1 out of service for maintenance by implementing the following compensatory measures:
- Communicate with the Diablo Canyon Power Plant (DCPP) Switching Center and Transmission Operations to ensure no elective maintenance or testing on the offsite power sources will be performed, and to verify offsite power sources are not in danger of being lost due to wild fires, other grid related events, or work activities.
" Provide assurance that storms or ocean swell events are not expected during the maintenance period.
" Assure that Operations, Maintenance, and Engineering are notified in the event of external events that may jeopardize offsite power sources, and that they determine if postponement of the battery maintenance is warranted.
- Avoid scheduling site activities that may cause a plant transient on the affected unit. Exceptions should be authorized in accordance with DCPP Administrative Procedure AD7.DC6, "On-Line Maintenance Risk Management."
- Avoid performing any testing or elective maintenance on the affected unit unless it is identified on the approved work week schedule. Exceptions may be approved by the shift manager or work week manager.
- Verify all parts and equipment necessary for the project have been procured and meet quality related checks.
- Post caution signs on the affected unit's battery room doors; reroute normal traffic during maintenance.
" Perform a walkdown verifying the other two batteries and associated areas are clean and in good material condition with no activities being performed, which could jeopardize operation.
1
Enclosure 1 PG&E Letter DCL-06-126
" Verify that redundant safety-related systems, subsystems, trains, components and devices that depend on the other two batteries are operable prior to beginning maintenance.
" Perform no elective maintenance or testing on components required to crosstie the vital 4kV buses between units as required by DCPP emergency operating procedures.
" Perform no elective maintenance or testing on components (other than normally scheduled surveillances) on affected unit's emergency diesel generators (EDGs).
NRC Question 2:
How will the proposed change affect the SBO [Station Blackout] coping capabilitiesof Diablo Canyon Unit 1?
PG&E Response:
SBO at DCPP is defined as loss of power from the 500kV and 230kV switchyards with the failure of twoEDGs to operate in one of the units. The other unit is assumed to experience only a loss of offsite power.
The DCPP SBO analysis was performed using the guidance provided in NUMARC 87-00, Revision 0, "Guidelines and Technical Bases for NUMARC Initiatives Addressing Station Blackout at Light Water Reactors," dated November 1987. During an SBO event, the SBO analysis demonstrated that the plant could be safely shutdown utilizing either Bus G or Bus H and their normally connected EDGs (emergency alternating current [AC] sources) and, thereby, the third EDG and its Bus F were declared the alternate AC (AAC) source. However, during an SBO event, any of the three EDGs may be used as the AAC source.
The turbine driven auxiliary feedwater (TDAFW) pump steam supply valve FCV-95 is powered from Battery 1-2. The level control valves (LCVs) for the TDAFW pump (LCV-106, -107, -108, and -109) are powered from 480V Bus G. Therefore, the proposed change would not affect the SBO coping capabilities of DCPP Unit 1.
2
Enclosure 1 PG&E Letter DCL-06-126
- Verify that redundant safety-related systems, subsystems, trains, components and devices that depend on the other two batteries are operable prior to beginning maintenance.
" Perform no elective maintenance or testing on components required to crosstie the vital 4kV buses between units as required by DCPP emergency operating procedures.
" Perform no elective maintenance or testing on components (other than normally scheduled surveillances) on affected unit's emergency diesel generators (EDGs).
NRC Question 2:
How will the proposed change affect the SBO [Station Blackout] coping capabilitiesof Diablo Canyon Unit 1?
PG&E Response:
SBO at DCPP is defined as loss of power from the 500kV and 230kV switchyards with the failure of two EDGs to operate in one of the units. The other unit is assumed to experience only a loss of offsite power.
The DCPP SBO analysis was performed using the guidance provided in NUMARC 87-00, Revision 0, "Guidelines and Technical Bases for NUMARC Initiatives Addressing Station Blackout at Light Water Reactors," dated November 1987. During an SBO event, the SBO analysis demonstrated that the plant could be safely shutdown utilizing either Bus G or Bus H and their normally connected EDGs (emergency alternating current [AC] sources) and, thereby, the third EDG and its Bus F were declared the alternate AC (AAC) source. However, during an SBO event, any of the three EDGs may be used as the AAC source.
The turbine driven auxiliary feedwater (TDAFW) pump steam supply valve FCV-95 is powered from Battery 1-2. The level control valves (LCVs) for the TDAFW pump (LCV-1 06, -107, -108, and -109) are powered from 480V Bus G. Therefore, the proposed change would not affect the SBO coping capabilities of DCPP Unit 1.
2
Enclosure 2 PG&E Letter DCL-06-126 Proposed Technical Specification Changes (retyped)
Remove Paqe Insert Page 3.8-18 3.8-18 3.8-18a
DC Sources - Operating 3.8.4 3.8 ELECTRICAL POWER SYSTEMS 3.8.4 DC Sources - Operating LCO 3.8.4 Three Class 1 E DC electrical power subsystems shall be OPERABLE.
APPLICABILITY: MODES 1, 2, 3, and 4.
ACTIONS CONDITION REQUIRED ACTION COMPLETION TIME A. One battery charger A.1 Restore battery terminal 2 hours2.314815e-5 days <br />5.555556e-4 hours <br />3.306878e-6 weeks <br />7.61e-7 months <br /> inoperable. voltage to greater than or equal to the minimum established float voltage.
AND A.2 Verify battery float 12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br /> current < 2 amps.
AND A.3 Restore battery charger 14 days to OPERABLE status.
(continued)
DIABLO CANYON - UNITS 1 & 2 3.8-18 Unit 1 - Amendment No. 4-35, 4-72, Unit 2 - Amendment No. 4-5, 174
DC Sources - Operating 3.8.4 ACTIONS (continued)
CONDITION REQUIRED ACTION COMPLETION TIME B. One battery inoperable. B.1 Restore battery to 2 hours2.314815e-5 days <br />5.555556e-4 hours <br />3.306878e-6 weeks <br />7.61e-7 months <br /> OPERABLE status.
OR B.2.1.1 ------- Note --
Required Actions B.2.1.1, B.2.1.2, and B.2.2 are applicable, on a one time basis, for Unit 1 cycle 14.
Determine OPERABLE 2 hours2.314815e-5 days <br />5.555556e-4 hours <br />3.306878e-6 weeks <br />7.61e-7 months <br /> batteries are not inoperable due to common cause failure.
OR B.2.1.2 Perform SR 3.8.4.1 and 2 hours2.314815e-5 days <br />5.555556e-4 hours <br />3.306878e-6 weeks <br />7.61e-7 months <br /> SR 3.8.6.1 for OPERABLE batteries.
AND B.2.2 Restore battery to 4 hours4.62963e-5 days <br />0.00111 hours <br />6.613757e-6 weeks <br />1.522e-6 months <br /> OPERABLE status.
C. One DC electrical power C.1 Restore DC electrical 2 hours2.314815e-5 days <br />5.555556e-4 hours <br />3.306878e-6 weeks <br />7.61e-7 months <br /> subsystem inoperable for power subsystem to reasons other than OPERABLE status.
Condition A or B.
D. More than one full capacity D.1 Restore the DC electrical 14 days charger receiving power power subsystem to a simultaneously from a configuration wherein single 480 V vital bus. each charger is powered from its associated 480 volt vital bus.
E. Required Action and E.1 Be in MODE 3. 6 hours6.944444e-5 days <br />0.00167 hours <br />9.920635e-6 weeks <br />2.283e-6 months <br /> Associated Completion AND Time not met.
36 hours4.166667e-4 days <br />0.01 hours <br />5.952381e-5 weeks <br />1.3698e-5 months <br /> E.2 Be in MODE 5.
DIABLO CANYON - UNITS 1 & 2 3.8-18a Unit 1 - Amendment No. 34,1-72, Unit 2 - Amendment No. 41-M5, 174
Enclosure 3 PG&E Letter DCL-06-126 Changes to Technical Specification Bases Pages (For information only)
DC Sources - Operating B 3.8.4 BASES ACTIONS B. 1 (continued)
Condition B represents one DC electrical power subsystem with one battery inoperable. With one battery inoperable, the DC bus is being supplied by the associated OPERABLE battery charger. Any event that results in a loss of the associated 480 Vac vital bus supporting the normal battery charger will also result in loss of or degraded DC to the associated DC electrical power subsystem. Recovery of the 480 Vac vital bus, especially if it is due to a loss of offsite power, will be hampered by the fact that many of the components necessary for the recovery (e.g., diesel generator control and field flash, AC load shed and diesel generator output circuit breakers, etc.) likely rely upon the battery. In addition, the energization transients of any DC loads that are beyond the capability of the battery charger and normally require the assistance of the battery will not be able to be brought online. The 2 hour2.314815e-5 days <br />5.555556e-4 hours <br />3.306878e-6 weeks <br />7.61e-7 months <br /> limit allows sufficient time to effect restoration of an inoperable battery given that the majority of the conditions that lead to battery inoperability (e.g., loss of battery charger, battery cell voltage less than 2.07 V, etc.) are identified in Specifications 3.8.4, 3.8.5, and 3.8.6 together with additional specific completion times.
B.2.1.1. B.2.1.2, B.2.2 The completion time for restoring the inoperable battery to OPERABLE status can be extended to 4 hours4.62963e-5 days <br />0.00111 hours <br />6.613757e-6 weeks <br />1.522e-6 months <br />, on a one-time basis for Unit 1 Vital Battery 1-1 for Unit 1 cycle 14, if additional Required Actions are taken.
The 4-hour completion time is based upon Probabilistic Risk Assessment (PRA) calculation of risk given one battery is inoperable.
This PRA assessment makes the assumptions that actions are taken to either determine that the OPERABLE batteries are not inoperable due to common cause failure or SR 3.8.4.1 and SR 3.8.6.1 are performed for the OPERABLE batteries. Taking steps to determine whether the battery condition is a result of a common cause failure will provide assurance that a similar failure will not occur to other OPERABLE batteries. Performing SR 3.8.4.1 and SR 3.8.6.1 will serve the same purpose of ensuring the OPERABLE batteries remain in OPERABLE condition. The 2-hour completion times for Required Actions B.2.1.1, and B.2.1.2 are consistent with completion time to restore a battery to OPERABLE status in Required Action B.1. When Required Actions B.2.1.1 or B.2.1.2 are met, then the inoperable battery can be restored to OPERABLE status in 4 hours4.62963e-5 days <br />0.00111 hours <br />6.613757e-6 weeks <br />1.522e-6 months <br />.
DIABLO CANYON - UNITS 1 & 2 53 Revision 4