DCL-24-094, License Amendment Request 24-04 Application to Revise Technical Specifications (TS) to Adopt TSTF-589 to Modify TS 3.3.5 and 3.8.2
| ML24325A495 | |
| Person / Time | |
|---|---|
| Site: | Diablo Canyon  |
| Issue date: | 11/20/2024 |
| From: | Rogers J Pacific Gas & Electric Co |
| To: | Office of Nuclear Reactor Regulation, Document Control Desk |
| References | |
| DCL-24-094 | |
| Download: ML24325A495 (1) | |
Text
Justin E. Rogers Station Director Diablo Canyon Power Plant Mail code 104/5/502 P.O. Box 56 Avila Beach, CA 93424 805.545.3088 Justin.Rogers@pge.com A member of the STARS (Strategic Teaming and Resource Sharing) Alliance Callaway
- Diablo Canyon
- Palo Verde
- Wolf Creek PG&E Letter DCL-24-094 10 CFR 50.90 U.S. Nuclear Regulatory Commission ATTN: Document Control Desk Washington, D.C. 20555-0001 Diablo Canyon Units 1 and 2 Docket No. 50-275, OL-DPR-80 Docket No. 50-323, OL-DPR-82 License Amendment Request 24-04 Application to Revise Technical Specifications (TS) to Adopt TSTF-589 to Modify TS 3.3.5 and 3.8.2
Dear Commissioners and Staff:
Pursuant to 10 CFR 50.90, Pacific Gas and Electric Company (PG&E) hereby requests approval of the enclosed proposed amendment to the Diablo Canyon Power Plant (DCPP), Units 1 and 2 Technical Specifications (TS).
PG&E requests adoption of TSTF-589, "Eliminate Automatic Diesel Generator Start During Shutdown," which is an approved change to the Standard Technical Specifications (STS), into the DCPP, Units 1 and 2 TS. TSTF-589 modifies the TS requirements for automatic diesel generator (DG) start and loading during shutdown consistent with NRC approved changes to NUREG-1431, Standard Technical Specifications, Westinghouse Plants, and industry practices.
The enclosure provides a description and assessment of the proposed changes. provides the existing TS pages marked up to show the proposed changes. Attachment 2 provides revised (clean) TS pages. Attachment 3 provides the existing TS Bases pages marked up to show revised text associated with the proposed TS changes and is provided for information only.
PG&E requests that the amendment be reviewed under the Consolidated Line Item Improvement Process (CLIIP). Approval of the proposed amendment is requested within 6 months of completion of the NRCs acceptance review. Once approved, the amendment shall be implemented within 180 days.
PG&E makes no regulatory commitments (as defined by NEI 99-04) in this letter.
This letter includes no revisions to existing regulatory commitments.
The enclosure to this letter contains the evaluation of the proposed change.
m Pacific Gas and Electric Company*
Document Control Desk PG&E Letter DCL-24-094 Page 2 A member of the STARS (Strategic Teaming and Resource Sharing) Alliance Callaway
- Comanche Peak
- Diablo Canyon
- Palo Verde
- Wolf Creek In accordance with site administrative procedures and the Quality Assurance Program, the proposed amendment has been reviewed by the Plant Staff Review Committee.
Pursuant to 10 CFR 50.91, PG&E is notifying the State of California of this license amendment request by transmitting a copy of this letter and enclosure to the California Department of Public Health.
If you have any questions or require additional information, please contact James Morris, Manager, Nuclear Regulatory Services, at 805-545-4609.
I state under penalty of perjury that the foregoing is true and correct.
Sincerely, Justin E. Rogers Station Director Date mjrm/51245650 Enclosure cc:
Diablo Distribution cc/enc: Anthony Chu, Branch Chief, California Dept of Public Health Mahdi O. Hayes, NRC Senior Resident Inspector Samson S. Lee, NRR Project Manager John Monninger, NRC Region IV Administrator 11/20/24
Enclosure PG&E Letter DCL-24-094 1
Evaluation of the Proposed Change
Subject:
License Amendment Request (LAR) 24-04, Application to Revise Technical Specifications (TS) to Adopt TSTF-589 to Modify TS 3.3.5 and 3.8.2
1.0 DESCRIPTION
2.0 ASSESSMENT
2.1 Applicability of Safety Evaluation 2.2 Variations
3.0 REGULATORY ANALYSIS
3.1 No Significant Hazards Consideration Analysis 3.2 Conclusion
4.0 ENVIRONMENTAL CONSIDERATION
ATTACHMENTS:
- 1. Proposed Technical Specification Changes (Mark-Up)
- 2. Revised Technical Specification Pages
- 3. Proposed Technical Specification Bases Changes (Mark-Up) - For Information Only
Enclosure PG&E Letter DCL-24-094 2
EVALUATION
1.0 DESCRIPTION
Pacific Gas and Electric Company (PG&E) requests adoption of TSTF-589, "Eliminate Automatic Diesel Generator Start During Shutdown," which is an approved change to the Standard Technical Specifications (STS), into the Diablo Canyon Power Plant (DCPP), Units 1 and 2 Technical Specifications (TS). TSTF-589 modifies the TS requirements for automatic diesel generator (DG) start and loading during shutdown conditions due to there being no regulatory or safety basis for a TS requirement for automatic DG start during Modes 5 and 6.
The proposed changes to SR 3.8.2.1 will continue to assure that the necessary quality of the onsite standby power systems and components is maintained, that facility operation will be within safety limits, and that the associated LCO 3.8.2 will be met in accordance with 10 CFR 50.36(c)(3).
2.0 ASSESSMENT
2.1 Applicability of Safety Evaluation PG&E has reviewed the safety evaluation for TSTF-589 provided to the Technical Specifications Task Force in a letter dated September 11, 2023. This review included a review of the NRC staffs evaluation, as well as the information provided in TSTF-589.
PG&E has concluded that the justifications presented in TSTF-589 and the safety evaluation prepared by the NRC staff are applicable to DCPP, Units 1 and 2, and justify this amendment for the incorporation of the changes to the DCPP, Units 1 and 2 TS.
The existing TS Surveillance Requirement (SR) 3.8.2.1 differs from the STS SR 3.8.2.1.
The existing TS SR 3.8.2.1 lists the TS 3.8.1 SRs that are applicable instead of the TS 3.8.1 SRs that are not applicable. This difference does not affect the applicability of the traveler to the DCPP TS.
2.2 Variations The existing TS SR 3.8.2.1 differs from the STS SR 3.8.2.1. The existing TS SR 3.8.2.1 contains differences in the applicable TS 3.8.1 SRs which must be met or performed.
The existing TS SR 3.8.2.1 does not require TS SR 3.8.1.13 to be met or performed.
This difference does not affect the applicability of the traveler to the DCPP TS.
The DCPP design and TS utilize:
- auto-transfer sequencing timers instead of automatic load sequencer
- load sequencing timers instead of automatic load sequencer
- auto-transfer load sequencing timer instead of load sequencer
- load sequencing timers instead of load sequencer
Enclosure PG&E Letter DCL-24-094 3
as described in the STS. This is applicable to TS SRs 3.8.1.11, 3.8.1.12, 3.8.1.18, and 3.8.1.19, respectively. However, none of those SRs are applicable for AC sources required to be OPERABLE in the proposed change to TS SR 3.8.2.1. Therefore, removal of those requirements during shutdown is consistent with the approved traveler and industry practices.
In the TS Bases Mark-Up Pages:
- Used "accepting the required loads manually" instead of "accepting required loads" (B 3.8.2 LCO)
- Used "response to a loss of offsite power" instead of "response on an offsite power" (B 3.8.2 TS SR 3.8.2.1)
- Used "safety injection signal" instead of "ECCS initiation signal" (B 3.8.2 TS SR 3.8.2.1)
- Language in B 3.8.2 TS SR 3.8.2.1 is modified to more closely match the STS.
None of these TS Bases changes affect the applicability of the traveler to the DCPP TS.
3.0 REGULATORY ANALYSIS
3.1 No Significant Hazards Consideration Analysis PG&E requests adoption of TSTF-589, "Eliminate Automatic Diesel Generator Start During Shutdown," which is an approved change to the STS, into the DCPP, Unit 1 and 2 TS. TSTF-589 eliminates the TS requirements for automatic diesel generator (DG) start and loading during shutdown.
PG&E has evaluated if a significant hazards consideration is involved with the proposed amendment(s) by focusing on the three standards set forth in 10 CFR 50.92, "Issuance of amendment," as discussed below:
- 1.
Does the proposed amendment involve a significant increase in the probability or consequences of an accident previously evaluated?
Response: No The proposed change eliminates the TS requirements for automatic DG start and loading during shutdown.
The proposed change does not alter any design function assumed in the accident analysis or the capability of any structure, system, or component (SSC) of the plant to perform a design function assumed in the accident analysis. The analysis of accidents initiated during shutdown does not assume a loss of offsite power or the automatic start and loading of a DG during shutdown.
Enclosure PG&E Letter DCL-24-094 4
Therefore, the proposed change does not affect the probability of an accident previously evaluated. Automatic detection of a loss of power, automatic load shedding of the Engineering Safety Feature (ESF) busses, and automatic start and loading of a DG onto the ESF busses is not assumed to mitigate the consequences of any previously evaluated accident initiated during shutdown.
As a result, there is no impact on the consequences of any accident previously evaluated.
Therefore, the proposed change does not involve a significant increase in the probability or consequences of an accident previously evaluated.
- 2.
Does the proposed amendment create the possibility of a new or different kind of accident from any accident previously evaluated?
Response: No The proposed change eliminates the TS requirements for automatic DG start and loading during shutdown.
The proposed change does not affect the ability of any SSC to perform the design functions assumed in the accident analysis. The proposed change does not create any credible new failure mechanisms, malfunctions, or accident initiators not considered in the design and licensing bases that would have been considered a design basis accident in the Final Safety Analysis Report (FSAR)
Update had it been previously identified.
Therefore, the proposed change does not create the possibility of a new or different kind of accident from any accident previously evaluated.
- 3.
Does the proposed amendment involve a significant reduction in a margin of safety?
Response: No The proposed change eliminates the TS requirements for automatic DG start and loading during shutdown.
The proposed change does not alter a design basis or safety limit (i.e., the controlling numerical value for a parameter established in the FSAR Update or the license) and does not affect any conservatism in the evaluation and analysis methods that are used to demonstrate compliance with regulatory and licensing requirements. As a result, the margin of safety is not significantly reduced.
Therefore, the proposed change does not involve a significant reduction in a margin of safety.
Enclosure PG&E Letter DCL-24-094 5
Based on the above, PG&E concludes that the proposed change presents no 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.
3.2 Conclusion In conclusion, based on the considerations discussed 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 Commissions 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
4.0 ENVIRONMENTAL CONSIDERATION
A review has determined that the proposed amendment would change a requirement with respect to installation or use of a facility component located within the restricted area, as defined in 10 CFR 20, or would change an inspection or surveillance requirement. However, the proposed amendment does not involve (i) a significant hazards consideration, (ii) a significant change in the types or a significant increase in the amounts of any effluents that may be released offsite, or (iii) a significant increase in individual or cumulative occupational radiation exposure. Accordingly, the proposed amendment meets the eligibility criterion for categorical exclusion set forth in 10 CFR 51.22(c)(9). Therefore, pursuant to 10 CFR 51.22(b), no environmental impact statement or environmental assessment need be prepared in connection with the proposed amendment
Enclosure PG&E Letter DCL-24-094 Proposed Technical Specification Changes (Mark-Up)
LOP DG Start Instrumentation 3.3.5 DIABLO CANYON - UNITS 1 & 2 3.3 INSTRUMENTATION 3.3.5 Loss of Power (LOP) Diesel Generator (DG) Start Instrumentation LCO 3.3.5 One channel per bus of loss of voltage DG start Function; and two channels per bus of degraded voltage Function shall be OPERABLE.
APPLICABILITY:
MODES 1, 2, 3, and 4 When associated DG is required to be OPERABLE by LCO 3.8.2, AC Sources-Shutdown.
ACTIONS
NOTE--------------------------------------------------------------
Separate Condition entry is allowed for each Function.
CONDITION REQUIRED ACTION COMPLETION TIME A. One or more Functions with one or more channels per bus inoperable.
A.1
NOTE---------------
One channel may be bypassed for up to 2 hours2.314815e-5 days <br />5.555556e-4 hours <br />3.306878e-6 weeks <br />7.61e-7 months <br /> for surveillance testing.
Enter applicable Condition(s) and Required Action(s) for the associated DG made inoperable by LOP DG start instrumentation.
Immediately SURVEILLANCE REQUIREMENTS SURVEILLANCE FREQUENCY SR 3.3.5.1 Not used SR 3.3.5.2 Perform TADOT.
In accordance with the Surveillance Frequency Control Program (continued) 3.3-41 Unit 1 - Amendment No. 135,142,165, 200, Unit 2 - Amendment No. 135, 142, 201, t-
AC Sources - Shutdown 3.8.2 DIABLO CANYON - UNITS 1 & 2 SURVEILLANCE REQUIREMENTS SURVEILLANCE FREQUENCY SR 3.8.2.1
NOTE---------------------------------
The following SRs are not required to be performed:
SR 3.8.1.3, SR 3.8.1.9 through, SR 3.8.1.1110, SR 3.8.1.14 through, and SR 3.8.1.16, and SR 3.8.1.18 (for auto-transfer timers).
For AC sources required to be OPERABLE, the following SRs of Specification 3.8.1, AC Sources -
Operating, are applicable; SR 3.8.1.1 through SR 3.8.1.7, SR 3.8.1.9 through SR 3.8.1.11, SR 3.8.1.14 through SR 3.8.1.16, and SR 3.8.1.18 (for auto-transfer timers)
The following SRs are applicable for AC sources required to be OPERABLE:
SR 3.8.1.1 SR 3.8.1.6 SR 3.8.1.2 SR 3.8.1.9 SR 3.8.1.3 SR 3.8.1.10 SR 3.8.1.4 SR 3.8.1.14 SR 3.8.1.5 SR 3.8.1.16 In accordance with applicable SRs 3.8-13 Unit 1 - Amendment No. 135, Unit 2 - Amendment No. 135,
Enclosure PG&E Letter DCL-24-094 Revised Technical Specification Page
LOP DG Start Instrumentation 3.3.5 DIABLO CANYON - UNITS 1 & 2 3.3 INSTRUMENTATION 3.3.5 Loss of Power (LOP) Diesel Generator (DG) Start Instrumentation LCO 3.3.5 One channel per bus of loss of voltage DG start Function; and two channels per bus of degraded voltage Function shall be OPERABLE.
APPLICABILITY:
MODES 1, 2, 3, and 4 ACTIONS
NOTE--------------------------------------------------------------
Separate Condition entry is allowed for each Function.
CONDITION REQUIRED ACTION COMPLETION TIME A. One or more Functions with one or more channels per bus inoperable.
A.1
NOTE---------------
One channel may be bypassed for up to 2 hours2.314815e-5 days <br />5.555556e-4 hours <br />3.306878e-6 weeks <br />7.61e-7 months <br /> for surveillance testing.
Enter applicable Condition(s) and Required Action(s) for the associated DG made inoperable by LOP DG start instrumentation.
Immediately SURVEILLANCE REQUIREMENTS SURVEILLANCE FREQUENCY SR 3.3.5.1 Not used SR 3.3.5.2 Perform TADOT.
In accordance with the Surveillance Frequency Control Program (continued) 3.3-41 Unit 1 - Amendment No. 135,142,165, 200, Unit 2 - Amendment No. 135, 142, 201,
AC Source - Shutdown 3.8.2 DIABLO CANYON - UNITS 1 & 2 SURVEILLANCE REQUIREMENTS SURVEILLANCE FREQUENCY SR 3.8.2.1
NOTE---------------------------------
The following SRs are not required to be performed:
SR 3.8.1.3, SR 3.8.1.9, SR 3.8.1.10, SR 3.8.1.14, and SR 3.8.1.16.
The following SRs are applicable for AC sources required to be OPERABLE:
SR 3.8.1.1 SR 3.8.1.6 SR 3.8.1.2 SR 3.8.1.9 SR 3.8.1.3 SR 3.8.1.10 SR 3.8.1.4 SR 3.8.1.14 SR 3.8.1.5 SR 3.8.1.16 In accordance with applicable SRs 3.8-13 Unit 1 - Amendment No. 135, Unit 2 - Amendment No. 135,
Enclosure PG&E Letter DCL-24-094 Proposed Technical Specification Bases Changes (Mark-Up)
(For Information Only)
LOP DG Start Instrumentation B 3.3.5 DIABLO CANYON - UNITS 1 & 2 Rev 14B BASES APPLICABLE SAFETY ANALYSES (continued)
Accident analyses credit the loading of the DG based on the loss of offsite power during a loss of coolant accident (LOCA). The actual DG start has historically been associated with the ESFAS actuation. The DG loading has been included in the delay time associated with each safety system component requiring DG supplied power following a loss of offsite power. The analyses assume a non-mechanistic DG loading, which does not explicitly account for each individual component of loss of power detection and subsequent actions.
The required channels of LOP DG start instrumentation, in conjunction with the ESF systems powered from the DGs, provide unit protection in the event of any of the analyzed accidents discussed in Reference 2, in which a loss of offsite power is assumed.
The delay times assumed in the safety analysis for the ESF equipment include the 10 second DG start delay, and the appropriate sequencing delay, if applicable. The response times for ESFAS actuated equipment in LCO 3.3.2, "Engineered Safety Feature Actuation System (ESFAS) Instrumentation," include the appropriate DG loading and sequencing delay.
The LOP DG start instrumentation channels satisfy Criterion 3 of 10 CFR 50.36(c)(2)(ii).
LCO The LCO for LOP DG start instrumentation requires that one channel per bus for loss of voltage DG start with, two channels per bus for initiation of load shed and their two corresponding timers and two channels per bus of degraded voltage function with one timer per bus for DG start and one timer per bus for initiation of load shed Functions shall be OPERABLE in MODES 1, 2, 3, and 4 when the LOP DG start instrumentation supports safety systems associated with the ESFAS.
In MODES 5 and 6, the channels must be OPERABLE whenever the associated DG is required to be OPERABLE to ensure that the automatic start of the DG is available when needed. Loss of the LOP DG Start Instrumentation Function could result in the delay of safety systems initiation when required. This could lead to unacceptable consequences during accidents. During the loss of offsite power the DG powers the motor driven auxiliary feedwater pumps. Failure of these pumps to start would leave only one turbine driven pump, as well as an increased potential for a loss of decay heat removal through the secondary system.
(continued)
LOP DG Start Instrumentation B 3.3.5 DIABLO CANYON - UNITS 1 & 2 Rev 13A BASES (continued)
APPLICABILITY The LOP DG Start Instrumentation Functions are required in MODES 1, 2, 3, and 4 because ESF Functions are designed to provide protection in these MODES. In MODES 5 and 6, automatic start of a DG is not assumed in the applicable safety analysis. Actuation in MODE 5 or 6 is required whenever the required DG must be OPERABLE so that it can perform its function on an LOP or degraded power to the Class 1E bus.
ACTIONS In the event a channel's Setpoint is found nonconservative with respect to the Allowable Value, or the channel is found inoperable, then the function that channel provides must be declared inoperable and the LCO Condition entered for the particular protection function affected.
Because the required channels are specified on a per bus basis, the Condition may be entered separately for each bus as appropriate.
A Note has been added in the ACTIONS to clarify the application of Completion Time rules. The Conditions of this Specification may be entered independently for each Function listed in the LCO. The Completion Time(s) of the inoperable channel(s) of a Function will be tracked separately for each Function starting from the time the Condition was entered for that Function.
A.1 Condition A applies when one or more of the loss of voltage or the degraded voltage channel functions (this includes both relays and timers) on a single bus are inoperable.
In these circumstances the Conditions specified in LCO 3.8.1, "AC Sources-Operating," or LCO 3.8.2, "AC Sources-Shutdown," for the DG made inoperable by failure of the LOP instrumentation are required to be entered immediately. The actions of those LCOs provide for adequate compensatory actions to assure unit safety.
A Note is added to allow bypassing one channel for up to 2 hours2.314815e-5 days <br />5.555556e-4 hours <br />3.306878e-6 weeks <br />7.61e-7 months <br /> for surveillance testing. This allowance is made where bypassing the channel does not cause an actuation and where at least one other channel is monitoring that parameter.
SURVEILLANCE REQUIREMENTS SR 3.3.5.1 not used SR 3.3.5.2 SR 3.3.5.2 is the performance of a TADOT. The test checks trip devices that provide actuation signals directly, bypassing the analog process control equipment. For these tests, the relay Setpoints are verified and adjusted as necessary. The Surveillance Frequency is based on operating experience, equipment reliability, and plant risk and is controlled under the Surveillance Frequency Control Program.
(continued)
AC Sources - Shutdown B 3.8.2 DIABLO CANYON - UNITS 1 & 2 Rev 14C BASES APPLICABLE SAFETY ANALYSES (continued)
- b.
Requiring appropriate compensatory measures for certain conditions. These may include administrative controls, reliance on systems that do not necessarily meet typical design requirements applied to systems credited in operating MODE analyses, or both.
- c.
Prudent utility consideration of the risk associated with multiple activities that could affect multiple systems.
- d.
Maintaining, to the extent practical, the ability to perform required functions (even if not meeting MODE 1, 2, 3, and 4 OPERABILITY requirements) with systems assumed to function during an event.
In the event of an accident during shutdown, this LCO ensures the capability to support systems necessary to avoid immediate difficulty, assuming either a loss of all offsite power or a loss of all onsite diesel generator (DG) power.
The AC sources satisfy Criterion 3 of 10 CFR 50.36(c)(2)(ii).
LCO One offsite circuit capable of supplying the onsite Class 1E power distribution subsystem(s) of LCO 3.8.10, "Distribution Systems Shutdown," ensures that all required loads are powered from offsite power. An OPERABLE DG, associated with the Class 1E AC electrical power distribution subsystem required to be OPERABLE by LCO 3.8.10, ensures a diverse power source is available to provide electrical power support, assuming a loss of the offsite circuit. Together, OPERABILITY of the required offsite circuit and the ability to manually start a DG ensures the availability of sufficient AC sources to operate the unit in a safe manner and to mitigate the consequences of postulated events during shutdown (e.g., fuel handling accidents involving handling recently irradiated fuel).
The qualified offsite circuit must be capable of maintaining rated frequency and voltage, and accepting required loads during an accident, while connected to the Engineered Safety Feature (ESF) bus(es). Qualified offsite circuits are those that are described in the UFSAR and are part of the licensing basis for the unit.
The Unit 1 Offsite Circuit #1 consists of Startup Transformer 1-1 supplied from the immediate access 230-kV Switchyard power source, which feeds Startup Transformer 1-2 through series supply breakers 52VU12 and 52VU14. Startup Transformer 1-2 then supplies power through breaker 52HG15 to each Class 1E bus feeder breaker (Bus F - 52HF14, Bus G - 52HG14, Bus H - 52HH14). The Unit 1 Offsite Circuit #2 is the delayed access 500-kV circuit which becomes available only after opening the motor operated disconnect to the main (continued)
AC Sources - Shutdown B 3.8.2 DIABLO CANYON - UNITS 1 & 2 Rev 14C BASES LCO (continued) generator. This circuit consists of Auxiliary Transformer 1-2 supplied from the 500-kV Switchyard through the main bank transformers.
Auxiliary Transformer 1-2 supplies power directly to each of the Class 1E bus feeder breakers (Bus F - 52HF13, Bus G - 52HG13, Bus H - 52HH13).
The Unit 2 Offsite Circuit #1 consists of Startup Transformer 2-1 supplied from the immediate access 230-kV Switchyard power source, which feeds Startup Transformer 2-2 through series supply breakers 52VU23 and 52VU24. Startup Transformer 2-2 then supplies power through breaker 52HG15 to each Class 1E bus feeder breaker (Bus F - 52HF14, Bus G - 52HG14, Bus H - 52HH14). The Unit 2 Offsite Circuit #2 is a delayed access circuit which only becomes available after opening the motor operated disconnect to the main generator. This circuit consists of Auxiliary Transformer 2-2 supplied from the 500-kV Switchyard through the main bank transformers.
Auxiliary Transformer 2-2 supplies power directly to each of the Class 1E bus feeder breakers (Bus F - 52HF13, Bus G - 52HG13, Bus H -3 52HH13).
Operating Procedure OP J-2:VIII (Ref. 20) provides guidelines for determining the operability of the 230-kV and 500-kV offsite power sources based on existing grid and plant conditions.
The DG must be capable of being manually started, starting, accelerating to rated speed and voltage, and connecting to its respective ESF bus and on detection of bus undervoltage. This sequence must be accomplished within 10 seconds. The DG must be capable of accepting the required loads manuallywithin the assumed loading sequence intervals, and continue to operate until offsite power can be restored to the ESF buses.
With administrative controls in place, it is acceptable for Class 1E AC electrical power distribution subsystems to be cross tied during shutdown conditions, allowing a single offsite power circuit or a single DG to supply the required Class 1E AC electrical power distribution subsystems.
The two redundant diesel fuel oil transfer pumps supply fuel oil to DG day tanks from either storage tank. One pump is adequate to supply the six DGs operating at full load. Only one train is required to be OPERABLE in MODES 5 or 6.
APPLICABILITY The AC sources required to be OPERABLE in MODES 5 and 6 and during movement of recently irradiated fuel assemblies provide assurance that:
- a.
Systems to provide adequate coolant inventory makeup are available for the irradiated fuel assemblies in the core;
- b.
Systems needed to mitigate a fuel handling accident involving handling recently irradiated fuel are available;
- c.
Systems necessary to mitigate the effects of events that can lead to core damage during shutdown are available; and (continued)
AC Sources - Shutdown B 3.8.2 DIABLO CANYON - UNITS 1 & 2 Rev 14C ACTIONS A.2.1, A.2.2, A.2.3, A.2.4, B.1, B.2, B.3, and B.4 (continued)
The Completion Time of immediately is consistent with the required times for actions requiring prompt attention. The restoration of the required AC electrical power sources should be completed as quickly as possible in order to minimize the time during which the unit safety systems may be without sufficient power.
Pursuant to LCO 3.0.6, the Distribution Systems ACTIONS would not be entered even if all AC sources to it are inoperable, resulting in de-energization. Therefore, the Required Actions of Condition A are modified by a Note to indicate that when Condition A is entered with no AC power to any required ESF bus, the ACTIONS for LCO 3.8.10 must be immediately entered. This Note allows Condition A to provide requirements for the loss of the offsite circuit, whether or not an AC electrical power distribution subsystem is de-energized. LCO 3.8.10 would provide the appropriate restrictions for the situation involving a de-energized AC electrical power distribution subsystem.
SURVEILLANCE REQUIREMENTS SR 3.8.2.1 SR 3.8.2.1 lists the SRs from LCO 3.8.1 that are applicable for ensuring the OPERABILITY of the AC sources in other than MODES 1, 2, 3, and
- 4. SR 3.8.1.8 is not required to be met since only one offsite circuit is required to be OPERABLE. SR 3.8.1.7, SR 3.8.1.11, SR 3.8.1.12, SR 3.8.1.13, SR 3.8.1.15, SR 3.8.1.18, and SR 3.8.1.19 are not required to be met because DG start and load within a specified time and response to a loss of offsite power or safety injection signal is not assumed in the accident analysis.SR 3.8.1.12, SR 3.8.1.13, SR 3.8.1.18 (for ESF timers), and SR 3.8.1.19 are excepted because SI response functions are not required to be OPERABLE. SR 3.8.1.17 is not required to be met because the required OPERABLE DG is not required to undergo periods of being synchronized to the offsite circuit. SR 3.8.1.20 is excepted because starting independence is not required with the DG that is not required to be OPERABLE.
This SR is modified by a Note which precludes listing the applicable SRs from LCO 3.8.1 that are not required to be performed. The reason for the Note is to preclude requiring the OPERABLE DG from being paralleled with the offsite power network or otherwise rendered inoperable during performance of an SR. The Note would also preclude deenergizing a required 4.16kV ESF bus or disconnecting a required offsite circuit for performance of an SR. With limited AC sources available, a single event could compromise both the required circuit and the DG. It is required that the DG and offsite circuit must still be capable of satisfying the acceptance criteria in these SRs. these SRs must be current. However, actual performance of these SRs is not required during periods when the DG and offsite circuit is required to be OPERABLE. must not take place on the required OPERABLE DG as it must be declared inoperable when paralleled to any of its associated off-site power sources. Only perform these surveillances when the minimum required OPERABLE diesel can be maintained.
Refer to the corresponding Bases for LCO 3.8.1 for a discussion of each SR.