DCL-16-001, License Amendment Request 16-01, Application to Revise Technical Specifications to Adopt TSTF-523, Generic Letter 2008-01. Managing Gas Accumulation, Using the Consolidated Line Item Improvement Process

License Amendment Request 16-01, Application to Revise Technical Specifications to Adopt TSTF-523, Generic Letter 2008-01. Managing Gas Accumulation, Using the Consolidated Line Item Improvement Process

ML16021A067
Person / Time
Site:	Diablo Canyon
Issue date:	01/21/2016
From:	Welsch J Pacific Gas & Electric Co
To:	Document Control Desk, Office of Nuclear Reactor Regulation
References
DCL-16-001, GL-2008-01
Download: ML16021A067 (58)

Text

{{#Wiki_filter:Pacific Gas .and Electric Company* James M. Welsch Diablo Canyon Power Plant Vice President, Nuclear Generation P.O. Box 56 Avila Beach, CA 93424 805.545.3242 E-Mail: JMWl@pge.com January 21, 2016 PG&E Letter DCL-16-001 U.S. Nuclear Regulatory Commission 10 CFR 50.90 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 16-01, Application to Revise Technical Specifications to Adopt TSTF-523. "Generic Letter 2008-01. Managing Gas Accumulation." Using the Consolidated Line Item Improvement Process

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 Facility Operating License Nos. DPR-80 and DPR-82 for Units 1 and 2 of the Diablo Canyon Power Plant (DCPP), respectively. The enclosed license.amendment request (LAR) proposes to revise Technical Specification (TS) 3.4.6 "RCS Loops- MODE 4," TS 3.4.7 "RCS Loops- MODE 5, Loops Filled," TS 3.4.8. "RCS Loops- MODE 5, Loops Not Filled," TS 3.5.2 "ECCS- Operating," TS 3.6.6 "Containment Spray and Cooling Systems," TS 3.9.5 "RHR and Coolant Circulation- High Water Level," and TS 3.9.6 "RHR and Coolant Circulation- Low Water Level." The proposed amendment would modify TS requirements to address Generic Letter 2008-01, "Managing Gas Accumulation in Emergency Core Cooling, Decay Heat Removal, and Containment Spray Systems," as described in Technical Specification Task Force TSTF-523, Revision 2, "Generic Letter 2008-01, Managing Gas Accumulation." The enclosure provides a description and assessment of the proposed change with three attachments. Attachment 1 provides the existing TS pages marked up to show the proposed change. Attachment 2 provides revised (clean) TS pages. Attachment 3 provides existing TS Bases pages marked to show the proposed change. Changes to the existing TS Bases, consistent with the technical and regulatory analyses, will be implemented under the Technical Specification Bases Control Program. They are provided in Attachment 3 for information only. A member of the STARS (Strategic Teaming and Resource Sharing) Alliance Callaway

• Diablo Canyon
• Palo Verde
• Wolf Creek

Document Control Desk PG&E Letter DCL-16-001 January 21, 2016 Page 2 The changes in this LAR are not required to address an immediate safety concern. PG&E requests approval of this LAR by no later than January 21, 2017. PG&E requests the license amendments to be effective upon NRC issuance of the license amendment, and to be implemented within 120 days from the date of issuance. PG&E makes no new or revised regulatory commitments (as defined by NEI 99-04) in this letter. In accordance with site administrative procedures and the Quality Assurance Program, the proposed amendment has been reviewed by the Plant Staff Review Committee. If you have any questions or require additional information, please contact Mr. Hossein Hamzehee at 805-545-4720. I state under penalty of perjury that the foregoing is true and correct. Executed on January 21, 2016. Sincerely, Jl.__- ,/lA 0dl...t_~ ~:~~~;lsch Vice President, Nuclear Generation aph8/64 70/50037662 Enclosure cc: Diablo Distribution cc/enc: Marc L. Dapas, NRC Region IV Binesh Tharakan, Acting NRC Senior Resident Inspector Siva P. Ling am, NRR Project Manager Gonzalo L. .Perez, Branch Chief, California Department of Public Health A member of the STARS (Strategic Teaming and Resource Sharing) Alliance Callaway

• Diablo Canyon
• Palo Verde
• Wolf Creek

Enclosure PG&E Letter DCL-16-001 Evaluation of the Proposed Change License Amendment Request 16-01 Application to Revise Technical Specifications to Adopt TSTF-523, "Generic Letter 2008-01, Managing Gas Accumulation," Using the Consolidated Line Item Improvement Process

Enclosure PG&E Letter DCL-16-001 Evaluation of the Proposed Change License Amendment Request 16-01 Application to Revise Technical Specifications to Adopt TSTF-523, "Generic Letter 2008-01, Managing Gas Accumulation," Using the Consolidated Line Item Improvement Process

1. DESCRIPTION

2. ASSESSMENT 2.1 Applicability of Published Safety Evaluation 2.2 Optional Changes and Variations

3. REGULATORY ANALYSIS 3.1 No Significant Hazards Consideration Determination

4. ENVIRONMENTAL EVALUATION ATTACHMENTS:

1. Proposed Technical Specification Changes

2. Revised Technical Specification Pages

3. Proposed Technical Specification Bases Changes 1

                                                                         ' Enclosure PG&E Letter DCL-16-001 Evaluation of the Proposed Change

1. DESCRIPTION The proposed change revises or adds Surveillance Requirements to verify that the system locations susceptible to gas accumulation are sufficiently filled with water and to provide allowances which permit performance of the verification.

The changes are being made to address the concerns discussed in Generic Letter 2008-01, "Managing Gas Accumulation in Emergency Core Cooling, Decay Heat Removal, and Containment Spray Systems." The proposed amendment is consistent with Technical Specification Task Force TSTF-523, Revision 2, "Generic Letter 2008-01, Managing Gas Accumulation."

2. ASSESSMENT 2.1 Applicability of Published Safety Evaluation Pacific Gas and Electric (PG&E) has reviewed the model safety evaluation dated January 15, 2014, as part of the Federal Register Notice of Availability. This review included a review of the NRC Staff's evaluation, as well as the information provided in TSTF-523. PG&E has concluded that the justifications presented in the TSTF-523 proposal and the model safety evaluation prepared by the NRC Staff are applicable to Diablo Canyon Units 1 and 2 and justify this amendment for the incorporation of the changes to the Diablo Canyon Technical Specifications (TS).

2.2 Optional Changes and Variations PG&E is not proposing any variations or deviations from the TS changes described in the TSTF-523, Revision 2, or the applicable parts of the NRC staff's model safety evaluation dated January 15, 2014.

3. REGULATORY ANALYSIS 3.1 No Significant Hazards Consideration Determination Pacific Gas and Electric Company (PG&E) requests adoption of TSTF-523, Revision 2, "Generic Letter 2008-01, Managing Gas Accumulation," which is an approved change to the standard technical specifications (STS), for the Diablo Canyon Units 1 and 2 TS. The proposed change revises or adds Surveillance Requirements to verify that the system locations susceptible to gas accumulation are sufficiently filled 2

Enclosure PG&E Letter DCL-16-001 with water and to provide allowances which permit performance of the verification. PG&E has evaluated whether or not 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 change involve a significant increase in the probability or consequences of an accident previously evaluated?

Response: No. The proposed change revises or adds Surveillance R~quirement(s) (SRs) that require verification that the Emergency Core Cooling System (ECCS), the Residual Heat Removal (RHR) System, and the Containment Spray (CS) System are not rendered inoperable due to accumulated gas and to provide allowances which permit performance of the revised verification. Gas accumulation in the s.ubject systems is not an initiator of any accident previously evaluated. As a result, the probability of any accident previously evaluated is not significantly increased. The proposed SRs ensure that the subject systems continue to be capable to perform their assumed safety function and are not rendered inoperable due to gas accumulation. Thus, the consequences of any accident previously evaluated are not significantly increased. Therefore, the proposed change does 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?

Response: No. The proposed change revises or adds SRs that require verification that the ECCS, RHR System, and CS System are not rendered inoperable due to accumulated gas and to provide allowances which permit performance of the revised verification. The proposed 3

Enclosure PG&E Letter DCL-16-001 change does not involve a physical alteration of the plant (i.e., no new or different type of equipment will be installed) or a change in the methods governing normal plant operation. In addition, the proposed change does not impose any new or different requirements that could initiate an accident. The proposed change does not alter assumptions made in the safety analysis and is consistent with the safety analysis assumptions. 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 change involve a significant reduction in a margin of safety?

Response: No. The proposed change revises or adds SRs that require verification that the ECCS, the RHR System, and the CS System are not rendered inoperable due to accumulated gas, and to provide allowances which permit performance of the revised verification. The proposed change adds new requirements to manage gas accumulation in order to ensure the subject systems are capable of performing their assumed safety functions. The proposed SRs are more comprehensive than the current SRs, and will ensure that the assumptions of the safety analysis are protected. The proposed change does not adversely affect any current plant safety margins or the reliability of the equipment assumed in the safety analysis. Therefore, there are no changes being made to any safety analysis assumptions, safety limits, or limiting safety system settings that would adversely affect plant safety as a result of the proposed change. Therefore, the proposed change does not involve a significant reduction in a margin of safety. 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. 4

Enclosure PG&E Letter DCL-16-001

4. ENVIRONMENTAL EVALUATION The proposed change 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 change does not involve (i) a significant hazards consideration, (ii) a significant change in the types or a significant increase in the amounts of any effluent that may be released offsite, or (iii) a significant increase in individual or cumulative occupational radiation exposure. Accordingly, the proposed change 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 change. 5

Enclosure Attachment 1 PG&E Letter DCL-16-001 Proposed Technical Specification Changes

Enclosure Attachment 1 PG&E Letter DCL-16-001 Proposed Technical Specification Changes Add TS Insert 1 to Page 3.4-11 TS Insert 1 SR -------------------------------~()TE:----------------------------- In accordance 3.4.6.4 ~ot required to be performed until 12 hours after with the entering M()DE: 4. Surveillance Frequency Verify required RHR loop locations susceptible to Control Program gas accumulation are sufficiently filled with water. Add TS Insert 2 to Page 3.4-13 TS Insert 2 SR 3.4.7.4 Verify required RHR loop locations susceptible to In accordance gas accumulation are sufficiently filled with water. with the Surveillance Frequency Control Program Add TS Insert 3 to Page 3.4-15 TS Insert 3 SR 3.4.8.3 Verify RHR loop locations susceptible to gas In accordance accumulation are sufficiently filled with water. with the Surveillance Frequency Control Program Add TS Insert 4 to Pages 3.5-4 and 3.6-15 TS Insert 4

                    ---------------------------------~()TE:---------------------------
                    ~ot required to be met for system vent flow paths opened under administrative control.

1

Enclosure Attachment 1 PG&E Letter DCL-16-001 Add TS Insert 5 to Page 3.5-5 TS Insert 5 Verify ECCS locations susceptible to gas accumulation are sufficiently filled with water. Add TS Insert 6 to Page 3.6-15 TS Insert 6 SR 3.6.6.4 Verify containment spray locations susceptible to In accordance gas accumulation are sufficiently filled with water. with the Surveillance Frequency Control Program Add TS Insert 7 to Page 3.9-5 TS Insert 7 SR 3.9.5.2 Verify required RHR loop locations susceptible to In accordance gas accumulation are sufficiently filled with water. with the Surveillance Frequency Control Program Add TS Insert 8 to Page 3.9-7 TS Insert 8 SR 3.9.6.3 Verify RHR loop locations susceptible to gas In accordance accumulation are sufficiently filled with water. with the Surveillance Frequency Control Program 2

RCS Loops - MODE 4 3.4.6 ACTIONS (continued) CONDITION REQUIRED ACTION COMPLETION TIME B. Two required loops B.1 Suspend operations that Immediately inoperable. would cause introduction of coolant into the RCS OR . with boron concentration less than required to meet SDM of LCO 3.1.1. AND No RCS or RHR loop in B.2 Initiate action to restore Immediately operation. one loop to OPERABLE status and operation. SURVEILLANCE REQUIREMENTS SURVEILLANCE FREQUENCY SR 3.4.6.1 Verify one RHR or RCS loop is in operation. In accordance with the Surveillance Frequency Control Program SR 3.4.6.2 Verify SG secondary side water levels are ;: : 15o/o for In accordance with required RCS loops. the Surveillance Frequency Control Program SR 3.4.6.3 Verify correct breaker alignment and indicated power In accordance with are available to the required pump that is not in the Surveillance operation. Frequency Control Program DIABLO CANYON - UNITS 1 & 2 3.4-11 Unit 1 - Amendment No. ~ +42 +M 2-Ge-,. Rev 10 Page 12 of 40 Unit 2 - Amendment No. ~ +42 §9. .f?k)+- Tab_3!4u3r1 O.DOC 0124.1255 '

RCS Loops - MODE 5, Loops Filled 3.4.7 ACTIONS CONDITION REQUIRED ACTION COMPLETION TIME A. One RHR loop inoperable. A.1 Initiate action to restore Immediately a second RHR loop to AND OPERABLE status. OR Required SGs secondary A.2 Initiate action to restore Immediately side water levels not within required SG secondary limits. side water levels to within limits. B. Required RHR loops B.1 Suspend operations that Immediately inoperable. would cause introduction of coolant into the RCS OR with boron concentration less than required to meet SDM of LCO 3.1 .1. AND No RHR loop in operation. B.2 Initiate action to restore Immediately one RH R loop to OPERABLE status and operation. SURVEILLANCE REQUIREMENTS SURVEILLANCE FREQUENCY SR 3.4.7.1 Verify one RHR loop is in operation. In accordance with the Surveillance Frequency Control Program SR 3.4.7.2 Verify SG secondary side water level is;::: 15°/o in In accordance with required SGs. the Surveillance Frequency Control Program SR 3.4.7.3 Verify correct breaker alignment and indicated power In accordance with are available to the required RHR pump that is not in the Surveillance operation. Frequency Control Program DIABLO CANYON - UNITS 1 & 2 3.4-13 Unit 1 - Amendment No. ~ §8 2GB*, Rev 10 Page 14 of 40 Unit 2 - Amendment No. ~ 99- *2-8-f 1 Tab_3!4u3r1 O.DOC 0124.1255

RCS Loops - MODE 5, Loops Not Filled 3.4.8 SURVEILLANCE REQUIREMENTS SURVEILLANCE FREQUENCY f SR 3.4.8.1 Verify one RHR loop is in operation. In accordance with the Surveillance Frequency Control Program t SR 3.4.8.2 Verify correct breaker alignment and indicated power In accordance with are available to the required RHR pump that is not in the Surveillance operation. Frequency Control Program DIABLO CANYON - UNITS 1 & 2 3.4-15 Unit 1 - Amendment No. +Je, 2BB-) Rev 10 Page 16 of 40 Unit 2 -Amendment No. +Je, ~ Tab_3!4u3r1 O.DOC 0124.1255

ECCS- Operating 3.5.2 SURVEILLANCE REQUIREMENTS SURVEILLANCE FREQUENCY f SR 3.5.2.1 Verify the following valves are in the listed position In accordance with with power to the valve operator removed. the Surveillance Frequency Control Number Position Function Program 8703 Closed RHR to RCS Hot Legs 8802A Closed Safety Injection to RCS Hot Legs 88028 Closed Safety Injection to RCS Hot Legs 8809A Open RHR to RCS Cold Legs 88098 Open RHR to RCS Cold Legs 8835 Open Safety Injection to RCS Cold Legs 8974A Open Safety Injection Pump Recirc. to RWST 89748 Open Safety Injection Pump Recirc. to RWST 8976 Open RWST to Safety Injection Pumps 8980 Open RWST to RHR Pumps 8982A Closed Containment Sump to RHR Pumps 89828 Closed Containment Sump to RHR Pumps 8992 Open Spray Additive Tank to Eductor 8701 Closed RHR Suction 8702 Closed RHR Suction SR 3.5.2.2 I*V Verify each ECCS manual, power operated, and automatic valve in the flow path, that is not locked, In accordance with the Surveillance S r* S6\z..:\ 'i sealed, or otherwise secured in position, is in the Frequency Control N

• correct position. Program SR 3.5.2. 3 V-eA.f.y'-E~~~-e.f~-. In accordance with the Surveillance Frequency Control

.!1\J~er!.T 5 Program (continued) ft\v vc. ~ rz. -;. '7. -z_ . .3 7"o PAb-t ~. S- 5 DIABLO CANYON - UNITS 1 & 2 3.5-4 Unit 1 - Amendment No. +&a, ~ ;

Rev 9 Page 4 of 8 Unit 2 - Amendment No. +&a, 2-9~- J Tab_3!5u3r09.DOC 1027.1544

ECCS- Operating 3.5.2 SURVEILLANCE REQUIREMENTS (continued) SURVEILLANCE FREQUENCY SR 3.5.2.4 Verify each ECCS pump's developed head at the test In accordance with flow point is greater than or equal to the required the lnservice developed head. Testing Program. SR 3.5.2.5 Verify each ECCS automatic valve in the flow path In accordance with that is not locked, sealed, or otherwise secured in the Surveillance position, actuates to the correct position on an actual Frequency Control or simulated actuation signal. Program SR 3.5.2.6 Verify each ECCS pump starts automatically on an In accordance with actual or simulated actuation signal. the Surveillance Frequency Control Program SR 3.5.2.7 Verify, for each ECCS throttle valve listed below, In accordance with each mechanical position stop is in the correct the Surveillance position. Frequency Control Program Charging Injection Safety Injection Throttle Valves Throttle Valves 8810A 8822A 88108 88228 8810C 8822C 88100 88220 SR 3.5.2.8 Verify, by visual inspection, each ECCS train In accordance with containment recirculation sump suction inlet is not the Surveillance restricted by debris and the suction inlet trash racks Frequency Control and screens show no evidence of structural distress Program or abnormal corrosion. DIABLO CANYON - UNITS 1 & 2 3.5-5 Unit 1 - Amendment No. +as, 2-e9-, Rev 9 Page 5 of 8 Unit 2 - Amendment No. +as, ~J Tab_3!5u3r09.DOC 1027.1544

Containment Spray and Cooling Systems 3.6.6 SURVEILLANCE REQUIREMENTS SURVEILLANCE FREQUENCY SR 3.6.6.1 \-..Verify each containment spray manual, power In accordance with the operated, and automatic valve in the flow path Surveillance Frequency

'JE\~I t...\ -          that is not locked, sealed, or otherwise secured        Control Program in position is in the correct position.

SR 3.6.6.2 Operate each CFCU for 2::. 15 minutes. In accordance with the Surveillance Frequency Control Program SR 3.6.6.3 Verify component cooling water flow rate to each In accordance with the required CFCU is 2::. 1650 gpm. Surveillance Frequency Control Program

• z..,- lc; SR 3.6.6 ..4_ "'5 Verify each containment spray pump's developed In accordance with the head at the flow test point is greater than or lnservice Testing equal to the required developed head. Program SR 3.6.6.-t \c Verify each automatic containment spray valve in In accordance with the the flow path that is not locked, sealed, or Surveillance Frequency otherwise secured in position, actuates to the Control Program correct position on an actual or simulated actuation signal.

SR 3.6.6.{ *1- Verify each containment spray pump starts In accordance with the automatically on an actual or simulated actuation Surveillance Frequency signal. Control Program SR 3.6.6.( B Verify each CFCU starts automatically on an In accordance with the actual or simulated actuation signal. Surveillance Frequency Control Program SR 3.6.6:A q Verify each spray nozzle is unobstructed. In accordance with the Surveillance Frequency Control Program SR 3.6.6 J.. \0 Verify each CFCU starts on low speed. In accordance with the Surveillance Frequency Control Program DIABLO CANYON - UNITS 1 & 2 3.6-15 Unit 1 - Amendment No. ~' ~e- , Rev 6 Page 15 of 18 Unit 2 - Amendment No. ~, 2-e1* J Tab_3!6u3r06.DOC 0416.1252

RHR and Coolant Circulation- High Water Level 3.9.5 SURVEILLANCE REQUIREMENTS SURVEILLANCE FREQUENCY SR 3.9.5.1 With the reactor subcritical less than 57 hours, In accordance with the verify one RHR loop is in operation and circulating Surveillance reactor coolant at a flow rate of;;::: 3000 gpm, Frequency Control Program With the reactor subcritical for 57 hours or more, In accordance with the verify one RHR loop is in operation and circulating Surveillance reactor coolant at a flow rate of;;::: 1300 gpm. Frequency Control Program DIABLO CANYON - UNITS 1 & 2 3.9-5 Unit 1 - Amendment No. ~' ~ CJ Rev 4 Page 8 of 11 Unit 2 - Amendment No. ~, *2ttr Tab_3!9u3r04.DOC 1027.1628 5

RHR and Coolant Circulation- Low Water Level 3.9.6 SURVEILLANCE REQUIREMENTS SURVEILLANCE FREQUENCY SR 3.9.6 .1 With the reactor subcritical less than 57 hours, In accordance with the verify one RHR loop is in operation and circulating Surveillance reactor coolant at a flow rate of;:::: 3000 gpm, Frequency Control Program In accordance with the With the reactor subcritical for 57 hours or more, Surveillance verify one RHR loop is in operation and circulating Frequency Control reactor coolant at a flow rate of ;: : 1300 gpm. Program SR 3.9.6.2 Verify correct breaker alignment and indicated In accordance with the power available to the required RHR pump that is Surveillance not in operation. Frequency Control Program DIABLO CANYON - UNITS 1 & 2 3.9-7 Unit 1 - Amendment No. ~' ~G-. , Rev 4 Page 10 of 11 Unit 2 - Amendment No. ~' ZG-1* 1 Tab_3!9u3r04.DOC 1027.1628

Enclosure Attachment 2 PG&E Letter DCL-16-001 Revised Technical Specification Pages

Enclosure Attachment 2 PG&E Letter DCL-16-001 Revised Technical Specification Pages Remove Page Insert Page 3.4-11 3.4-11 3.4-13 3.4-13 3.4-15 3.4-15 3.5-4 3.5-4 3.5-5 3.5-5 3.6-15 3.6-15, 3.6-15a 3.9-5 3.9-5 3.9-7 3.9-7

RCS Loops - MODE 4 3.4.6 ACTIONS (continued) CONDITION REQUIRED ACTION COMPLETION TIME B. Two required loops B.1 Suspend operations that Immediately inoperable. would cause introduction of coolant into the RCS OR with boron concentration less than required to meet SDM of LCO 3.1.1. AND No RCS or RHR loop in B.2 Initiate action to restore Immediately operation. one loop to OPERABLE status and operation. SURVEILLANCE REQUIREMENTS SURVEILLANCE FREQUENCY SR 3.4.6.1 Verify one RHR or RCS loop is in operation. In accordance with the Surveillance Frequency Control Program SR 3.4.6.2 Verify SG secondary side water levels are ;::: 15% for In accordance with required RCS loops. the Surveillance Frequency Control Program SR 3.4.6.3 Verify correct breaker alignment and indicated power In accordance with are available to the required pump that is not in the Surveillance operation. Frequency Control Program SR 3.4.6.4 -------------------------------N0 T E------------------------------ In accordance with Not required to be performed until 12 hours after the Surveillance entering MODE 4. Frequency Control Program Verify required RHR loop locations susceptible to gas accumulation are sufficiently filled with water. DIABLO CANYON - UNITS 1 & 2 3.4-11 Unit 1 -Amendment No.~~ W 2-00, Rev 11 Page 12 of 40 Unit 2- Amendment No.~~ -ie9 ~.

RCS Loops - MODE 5, Loops Filled 3.4.7 ACTIONS CONDITION REQUIRED ACTION COMPLETION TIME A. One RHR loop inoperable. A.1 Initiate action to restore Immediately a second RHR loop to AND OPERABLE status. OR Required SGs secondary A.2 Initiate action to restore Immediately side water levels not within required SG secondary limits. side water levels to within limits. B. Required RHR loops B.1 Suspend operations that Immediately inoperable. would cause introduction of coolant into the RCS OR with boron concentration less than required to meetSDM ofLC03.1.1. AND No RHR loop in operation . B.2 Initiate action to restore Immediately one RHR loop to OPERABLE status and operation. SURVEILLANCE REQUIREMENTS SURVEILLANCE FREQUENCY SR 3.4.7.1 Verify one RHR loop is in operation. In accordance with the Surveillance Frequency Control Program SR 3.4.7.2 Verify SG secondary side water level is ; : : 15% in In accordance with required SGs. the Surveillance Frequency Control Program SR 3.4.7.3 Verify correct breaker alignment and indicated power In accordance with are available to the required RHR pump that is not in the Surveillance operation. Frequency Control Program SR 3.4.7.4 Verify required RHR loop locations susceptible to gas In accordance with accumulation are sufficiently filled with water. the Surveillance Frequency Control Program DIABLO CANYON - UNITS 1 & 2 3.4-13 Unit 1 -Amendment No. ~-tag 2-00-, Rev 11 Page 14 of 40 Unit 2 -Amendment No. ~ W W-i,

RCS Loops - MODE 5, Loops Not Filled 3.4.8 SURVEILLANCE REQUIREMENTS SURVEILLANCE FREQUENCY SR 3.4.8.1 Verify one RHR loop is in operation. In accordance with the Surveillance Frequency Control Program SR 3.4.8.2 Verify correct breaker alignment and indicated power In accordance with are available to the required RHR pump that is not in the Surveillance operation. Frequency Control Program SR 3.4.8.3 Verify RHR loop locations susceptible to gas In accordance with accumulation are sufficiently filled with water. the Surveillance Frequency Control Program DIABLO CANYON - UNITS 1 & 2 3.4-15 Unit 1 -Amendment No. ~, 00, Rev 11 Page 16 of 40 Unit 2 -Amendment No. ~ ' 2G-1-,

ECCS - Operating 3.5.2 SURVEILLANCE REQUIREMENTS SURVEILLANCE FREQUENCY SR 3.5.2.1 Verify the following valves are in the listed position In accordance with with power to the valve operator removed. the Surveillance Frequency Control Number Position Function Program 8703 Closed RHR to RCS Hot Legs 8802A Closed Safety Injection to RCS Hot Legs 88028 Closed Safety Injection to RCS Hot Legs 8809A Open RHR to RCS Cold Legs 88098 Open RHR to RCS Cold Legs 8835 Open Safety Injection to RCS Cold Legs 8974A Open Safety Injection Pump Recirc. to RWST 89748 Open Safety Injection Pump Recirc. to RWST 8976 Open RWST to Safety Injection Pumps 8980 Open RWST to RHR Pumps 8982A Closed Containment Sump to RHR Pumps 89828 Closed Containment Sump to RHR Pumps 8992 Open Spray Additive Tank to Eductor 8701 Closed RHR Suction 8702 Closed RHR Suction SR 3.5.2.2 ------------------------------N0 T E--------------------------------- Not required to be met for system vent flow paths opened under administrative control. Verify each ECCS manual , power operated, and In accordance with automatic valve in the flow path, that is not locked, the Surveillance sealed, or otherwise secured in position, is in the Frequency Control correct position. Program (continued) DIABLO CANYON - UNITS 1 & 2 3.5-4 Unit 1 -Amendment No. ~. 200, Rev 10 Page 4 of 8 Unit 2 - Amendment No. ~ . ;w..t,

ECCS - Operating 3.5.2 SURVEILLANCE REQUIREMENTS (continued) SURVEILLANCE FREQUENCY SR 3.5.2.3 Verify ECCS locations susceptible to gas In accordance with accumulation are sufficiently filled with water. the Surveillance Frequency Control Program SR 3.5.2.4 Verify each ECCS pump's developed head at the test In accordance with flow point is greater than or equal to the required the Inservice developed head. Testing Program. SR 3.5.2.5 Verify each ECCS automatic valve in the flow path In accordance with that is not locked, sealed, or otherwise secured in the Surveillance position, actuates to the correct position on an actual Frequency Control or simulated actuation signal. Program SR 3.5.2.6 Verify each ECCS pump starts automatically on an In accordance with actual or simulated actuation signal. the Surveillance Frequency Control Program SR 3.5.2.7 Verify, for each ECCS throttle valve listed below, In accordance with each mechanical position stop is in the correct the Surveillance position. Frequency Control Program Charging Injection Safety Injection Throttle Valves Throttle Valves 8810A 8822A 88108 88228 8810C 8822C 88100 88220 SR 3.5.2.8 Verify, by visual inspection, each ECCS train In accordance with containment recirculation sump suction inlet is not the Surveillance restricted by debris and the suction inlet trash racks Frequency Control and screens show no evidence of structural distress Program or abnormal corrosion. DIABLO CANYON - UNITS 1 & 2 3.5-5 Unit 1 -Amendment No.~'~, Rev 10 Page 5 of 8 Unit 2 - Amendll}ent No. ~, ~,

Containment Spray and Cooling Systems 3.6.6 SURVEILLANCE REQUIREMENTS SURVEILLANCE FREQUENCY SR 3.6.6.1 ---------------------------N0 T E------------------------------ Not required to be met for system vent flow paths opened under administrative control. Verify each containment spray manual, power In accordance with the operated, and automatic valve in the flow path Surveillance Frequency that is not locked, sealed, or otherwise secured in Control Program position is in the correct position. SR 3.6.6.2 Operate each CFCU for~ 15 minutes. In accordance with the Surveillance Frequency Control Program SR 3.6.6.3 Verify component cooling water flow rate to each In accordance with the required CFCU is~ 1650 gpm. Surveillance Frequency Control Program SR 3.6.6.4 Verify containment spray locations susceptible to In accordance with the gas accumulation are sufficiently filled with water. Surveillance Frequency Control Program SR 3.6.6.5 Verify each containment spray pump's developed In accordance with the head at the flow test point is greater than or Inservice Testing equal to the required developed head. Program SR 3.6.6.6 Verify each automatic containment spray valve in In accordance with the the flow path that is not locked, sealed, or Surveillance Frequency otherwise secured in position, actuates to the Control Program correct position on an actual or simulated actuation signal. SR 3.6.6.7 Verify each containment spray pump starts In accordance with the automatically on an actual or simulated actuation Surveillance Frequency signal. Control Program SR 3.6.6.8 Verify each CFCU starts automatically on an In accordance with the actual or simulated actuation signal. Surveillance Frequency . Control Program (continued) DIABLO CANYON - UNITS 1 & 2 3.6-15 Unit 1 -Amendment No. ~. 2-00, Rev 7 Page 15 of 19 Unit 2 -Amendment No. ~ , 2-Q.i,

Containment Spray and Cooling Systems 3.6.6 SURVEILLANCE REQUIREMENTS (continued) SURVEILLANCE FREQUENCY SR 3.6.6.9 Verify each spray nozzle is unobstructed. In accordance with the Surveillance Frequency Control Program SR 3.6.6.10 Verify each CFCU starts on low speed . In accordance with the Surveillance Frequency Control Program DIABLO CANYON - UNITS 1 & 2 3.6-15a Unit 1 -Amendment No. ~. 2-00, Rev 7 Page 16 of 19 Unit 2 -Amendment No. ~. 2-G-4-,

RHR and Coolant Circulation - High Water Level 3.9.5 SURVEILLANCE REQUIREMENTS SURVEILLANCE FREQUENCY SR 3.9.5.1 With the reactor subcritical less than 57 hours, In accordance with the verify one RHR loop is in operation and circulating Surveillance reactor coolant at a flow rate of~ 3000 gpm, Frequency Control OR Program With the reactor subcritical for 57 hours or more, In accordance with the verify one RHR loop is in operation and circulating Surveillance reactor coolant at a flow rate of~ 1300 gpm. Frequency Control Program SR 3.9.5.2 Verify required RHR loop locations susceptible to In accordance with the gas accumulation are sufficiently filled with water. Surveillance Frequency Control Program DIABLO CANYON - UNITS 1 & 2 3.9-5 Unit 1 -Amendment No.~.~. Rev 5 Page 8 of 11 Unit 2 -Amendment No. ~. :2-G-i,

RHR and Coolant C_irculation - Low Water Level 3.9.6 SURVEILLANCE REQUIREMENTS SURVEILLANCE FREQUENCY SR 3.9.6.1 With the reactor subcritical less than 57 hours, In accordance with the verify one RHR loop is in operation and circulating Surveillance reactor coolant at a flow rate of;::: 3000 gpm, Frequency Control Program In accordance with the With the reactor subcritical for 57 hours or more, Surveillance verify one RHR loop is in operation and circulating Frequency Control reactor coolant at a flow rate of;::: 1300 gpm. Program SR 3.9.6.2 Verify correct breaker alignment and indicated In accordance with the power available to the required RHR pump that is Surveillance not in operation. Frequency Control Program SR 3.9.6.3 Verify RHR loop locations susceptible to gas In accordance with the accumulation are sufficiently filled with water. Surveillance Frequency Control Program DIABLO CANYON - UNITS 1 & 2 3.9-7 Unit 1 -Amendment No. 4J.a, 2-00, Rev 5 Page 10 of 11 Unit 2 -Amendment No. 4J.a, 2-G-i,

Enclosure Attachment 3 PG&E Letter DCL-16-001 Technical Specification Bases Changes (For information only)

RCS Loops - MODE 4 B 3.4.6 BASES LCO (continued) temperature difference limits the available relative energy source and the pressurizer level condition provides an expansion volume to accommodate possible reactor coolant thermal swell. These conditions are intended to prevent a low temperature overpressure event due to a thermal transient when a RCP is started. An OPERABLE RCS loop comprises an OPERABLE RCP and an OPERABLE SG, which has the minimum water level specified in SR 3.4.6.2. Similarly for the RHR System, an OPERABLE RHR loop comprises an OPERABLE RHR pump capable of providing forced flow to an OPERABLE RHR heat exchanger. RCPs and RHR pumps are OPERABLE if they are capable of being powered and are able to provide forced flow if required. A RHR loop is in operation when the pump is operating and providing forced flow through the loop. Because a loop can be operating without being OPERABLE, the LCO requires at least one loop OPERABLE and in operation. Management of gas voids is important to RHR System OPERABILITY. APPLICABILITY In MODE 4, this LCO ensures forced circulation of the reactor coolant to remove decay heat from the core and to provide proper boron mixing. One loop of either RCS or RHR provides sufficient circulation for these purposes. However, two loops consisting of any combination of RCS and RHR loops are required to be OPERABLE to meet single failure considerations. Operation in other MODES is covered by: LCO 3.4.4, "RCS Loops - MODES 1 and 2"; LCO 3.4.5, "RCS Loops - MODE 3"; LCO 3.4.7, "RCS Loops- MODE 5, Loops Filled"; LCO 3.4.8, "RCS Loops - MODE 5, Loops Not Filled"; LCO 3.9.5, "Residual Heat Removal (RHR) and Coolant Circulation-High Water Level" (MODE 6); and LCO 3.9.6, "Residual Heat Removal (RHR) and Coolant Circulation-Low Water Level" (MODE 6). ACTIONS A.1 and A.2 If one required RCS loop is inoperable and two RHR loops are inoperable, redundancy for heat removal is lost. Action must be initiated to restore a second RCS loop or RHR loop to OPERABLE status. The immediate Completion Time reflects the importance of maintaining the availability of two paths for heat removal. (continued) DDIABLO CANYON- UNITS 1 & 2 Rev 8A Page 26 of 108 B3.4.x.DOCTab B3!4u3rm~ . DOC 0120.16270919.1043 1.1-1

RCS Loops - MODE 4 B 3.4.6 BASES SURVEILLANCE SR 3.4.6.2 REQUIREMENTS SR 3.4.6.2 requires verification of SG OPERABILITY. SG (continued) OPERABILITY is verified by ensuring that the secondary side narrow range water level is ~ 15%. If the SG secondary side narrow range water level is < 15%, the tubes may become uncovered and the associated loop may not be capable of providing the heat sink necessary for removal of decay heat. The Surveillance Frequency is based on operating experience, equipment reliability, and plant risk and is controlled under the Surveillance Frequency Control Program. SR 3.4.6.3 Verification that the required pump is OPERABLE ensures that an additional RCS or RHR pump can be placed in operation, if needed, to maintain decay heat removal and reactor coolant circulation. Verification is performed by verifying proper breaker alignment and power available to the required pump. The Surveillance Frequency is based on operating experience, equipment reliability, and plant risk and is controlled under the Surveillance Frequency Control Program. SR 3.4 .6.4 _ __ _ _ _______ _ _________ _ _ _ __ __ _ _ _ _____ ___ __ __ - 1~.....F_o_rm _ att _e_d_:_un_d_er_lin_e_ _ _ _ _ __.~ RHR System piping and components have the potential to develop voids and pockets of entrained gases. Preventing and managing gas intrusion and accumulation is necessary for proper operation of the required RHR loop(s) and may also prevent water hammer, pump cavitation, and pumping of noncondensible gas into the reactor vessel. Selection of RHR System locations susceptible to gas accumulation is based on a review of system design information. including piping and instrumentation drawings. isometric drawings. plan and elevation drawings, and calculations. The design review is supplemented by system walk downs to validate the system high points and to confirm the location and orientation of important components that can become sources of gas or could otherwise cause gas to be trapped or difficult to remove during system maintenance or restoration . Susceptible locations depend on plant and system configuration . such as stand-by versus operating conditions . The RHR System is OPERABLE when it is sufficiently filled with water. Acceptance criteria are established for the volume of accumulated gas at susceptible locations. If accumulated gas is discovered that exceeds the acceptance criteria for the susceptible location (or the volume of accumulated gas at one or more susceptible locations exceeds an acceptance criteria for gas volume at the suction or discharge of a pump) the Surveillance is not met. If it is determined by subsequent eva luation that the RHR System is not rendered inoperable by the accumulated gas (i.e. the system is sufficiently filled with water) , the Surveillance may be declared met. Accumulated gas should be DDIABLO CANYON- UNITS 1 & 2 Rev 8A Page 28 of 108 B3.4.x.DOCTab B3 !4t:J3rog .ooc 0120.16270919.1043 1.1-1

RCS Loops - MODE 4 B 3.4.6 Surveillance may be declared met. Accumulated gas should be eliminated or brought within the acceptance criteria limits. RHR System locations susceptible to gas accumulation are monitored and. if gas is found . the gas volume is compared to the acceptance criteria for the location . Susceptible locations in the same system flow path which are subject to the same gas intrusion mechanisms may be verified by monitoring a representative sub-set of susceptible locations. Monitoring may not be practical for locations that are inaccessible due to radiological or environmental conditions . the plant configuration . or personnel safety. For these locations alternative methods (e.g .. operating parameters . remote monitoring) may be used to monitor the susceptible location. Monitoring is not required for susceptible locations where the maximum potential accumulated gas void volume has been evaluated and determined to not challenge system OPERABILITY. The accuracy of the method used for monitoring the susceptible locations and trending of the results should be sufficient to assure system OPERABILITY during the Surveillance interval. This SR is modified by a Note that states the SR is not required to be performed until 12 hours after entering MODE 4. In a rapid shutdown. there may be insufficient time to verify all susceptible locations prior to entering MODE 4. The Surveillance Frequency is controlled under the Surveillance Frequency Control Program . The Surveillance Frequency may vary by location susceptible to gas accumulation .

                                                                                                                    .- --- - - -{ Formatted Table REFERENCES            1. Diablo Canyon Power Plant Pressure and Temperature Limits Report.

2. LAR 16-01 Application to Revise Technical Specifications to Adopt TSTF-523 , "Generic Letter 2008-01 . Managing Gas Accumulation ," Using the Consolidated Line Item Improvement Process.

                                                                                                                                  ,.( Deleted: Tab_83!4u3r08.DOC
                                                                                                                                                                 =====<
                                                                                                                            ',*,*:A Deleted: 0919.1043 DDIABLO CANYON- UNITS 1 & 2                                                                                                

Rev SA Page 29 of 108 ,./ Tab B3!4u3r08. DO C, __________________________ 0121 .064§,__________________________________________________________ / 1.1 -1

RCS Loops - MODE 5, Loops Filled B 3.4.7 BASES LCO The Note specifies that a RCP may be started if the pressurizer water (continued) level is less than 50% . This option of RCP start with pressurizer water level less than 50% supports plant operational flexibility. The open volume in the pressurizer provides space to sustain reactor coolant thermal swell without incurring a possible excessive pressure transient due to energy additions from the S/G secondary water. The purpose of conditions to allow initial RCP start when none is running is to prevent a possible low temperature RCS overpressure event due to a thermal transient when a RCP is started. The condition of SG/RCS temperature difference limits the available relative energy source and the pressurizer level condition provides an expansion volume to accommodate possible reactor coolant thermal swell . These conditions are intended to prevent a low temperature overpressure event due to a thermal transient when a RCP is started. Note 4 provides for an orderly transition from MODE 5 to MODE 4 during a planned heatup by permitting removal of RHR loops from operation when at least one RCS loop is in operation. This Note provides for the transition to MODE 4 where an RCS loop is permitted to be in operation and replaces the RCS circulation function provided by the RHR loops. RHR pumps are OPERABLE if they are capable of being powered and are able to provide flow if required. A SG can perform as a heat sink via natural circulation when it has an adequate water level and is OPERABLE. Management of gas voids is important to RHR System OPERABILITY. APPLICABILITY "Loops filled" is a condition in which natural circulation can be used as a backup means of decay heat removal if forced circulation via RHR is lost. RCS loops are considered filled when the RCS is capable of being pressurized to at least 150 psig, no gas has been directly injected into the RCS, and the RCS has not been drained below 112 ft (Ref. 2). In addition to these requirements, crediting heat removal via natural circulation requires at least two steam generators filled to 2::15% narrow range level and vented, or capable of being vented, to the atmosphere, and auxiliary feedwater available to add water to the relied-upon steam generators (Ref. 1). A loops filled condition is established at the completion of steam generator U-tube vacuum refill or after "bumping" RCPs. In MODE 5 with RCS loops filled, this LCO requires forced circulation of the reactor coolant to remove decay heat from the core and to provide proper boron mixing . One loop of RHR provides sufficient circulation for these purposes. However, one additional RHR loop is required to be OPERABLE, or the secondary side water level of at least two SGs is required to be ;;::: 15%. (continued) DDIABLO CANYON- UNITS 1 & 2 Rev 8A Page 32 of 108 B3.4.x.DOCTab B3!4u3FO!lDOC 0120.16270919.1043 1.1-1

RCS Loops - MODE 5, Loops Filled B 3.4.7 BASES SURVEILLANCE SR 3.4.7.2 REQUIREMENTS Verifying that at least two SGs are OPERABLE by ensuring their (continued) secondary side narrow range water levels are 2: 15% ensures an alternate decay heat removal method via natural circulation in the event that the second RHR loop is not OPERABLE. If both RHR loops are OPERABLE, this Surveillance is not needed . The Surveillance Frequency is based on operating experience, equipment reliability, and plant risk and is controlled under the Surveillance Frequency Control Program. SR 3.4.7.3 Verification that a second RHR pump is OPERABLE ensures that an additional pump can be placed in operation , if needed, to maintain decay heat removal and reactor coolant circulation. Verification is performed by verifying proper breaker alignment and power available to the RHR pump. If secondary side water level is 2: 15% in at least two SGs, this Surveillance is not needed. The Surveillance Frequency is based on operating experience, equipment reliability, and plant risk and is controlled under the Surveillance Frequency Control Program. SR 3.4.7.4 - ---- ---- - - -- - ------------ - - --- ----- ------~

                                                                                                    - Formatted: Underline RHR System piping and components have the potential to develop                    Formatted: Underline voids and pockets of entrained gases. Preventing and managing gas intrusion and accumulation is necessary for proper operation of the required RHR loop(s) and may also prevent water hammer, pump cavitation . and pumping of noncondensible gas into the reactor vessel.

Selection of RHR System locations susceptible to gas accumulation is based on a review of system design information. including piping and instrumentation drawings. isometric drawings, plan and elevation drawings. and calculations . The design review is supplemented by system walk downs to validate the system high points and to confirm the location and orientation of important .components that can become sources of gas or could otherwise cause gas to be trapped or difficult to remove during system maintenance or restoration . Susceptible locations depend on plant and system configuration, such as stand-by versus operating conditions . The RHR System is OPERABLE when it is sufficiently filled with water. Acceptance criteria are established for the volume of accumulated gas at susceptible locations . If accumulated gas is discovered that exceeds the acceptance criteria for the susceptible location (or the volume of accumulated gas at one or more susceptible locations exceeds an acceptance criteria for gas volume at the suction or discharge of a pump) , the Surveillance is not met. If it is determined by subsequent eva luation that the RHR System is not rendered inoperable by the accumulated gas (i.e .. the system is sufficiently filled with water), the DDIABLO CANYON - UNITS 1 & 2 Rev 8A Page 35 of 108 B3.4.x.DOCTab Ba !4t:Jarog.ooc 0120.16270919.104a 1.1-1

RCS Loops - MODE 5, Loops Filled B 3.4.7 accumulated gas (i.e .. the system is sufficiently filled with water). the Surveillance may be declared met. Accumulated gas should be eliminated or brought within the acceptance criteria limits. RHR System locations susceptible to gas accumulation are monitored and . if gas is found. the gas volume is compared to the acceptance criteria for the location . Susceptible locations in the same system flow path which are subject to the same gas intrusion mechanisms may be verified by monitoring a representative sub-set of susceptible locations . Monitoring may not be practical for locations that are inaccessible due to radiological or environmental conditions. the plant configuration . or personnel safety. For these locations alternative methods (e.g .. operating parameters. remote monitoring) may be used to monitor the susceptible location. Monitoring is not required for susceptible locations where the maximum potential accumulated gas void volume has been evaluated and determined to not challenge system OPERABILITY. The accuracy of the method used for monitoring the susceptible locations and trending of the results should be sufficient to assure system OPERABILITY during the Surveillance interval. The Surveillance Frequency is controlled under the Surveillance Frequency Control Program . The Surveillance Frequency may vary by location susceptible to gas accumulation . REFERENCES 1. NRC Information Notice 95-35, "Degraded Ability of Steam Generators to Remove Decay Heat by Natural Circulation ."

2. AR A0582812.

3. LAR 16-01 Application to Revise Technical Specifications to Adopt TSTF-523 . "Generic Letter 2008-01 . Managing Gas Accumulation." Using the Consolidated Line Item Improvement Process.

                                                                                                                  ,{ Deleted: Tab_B3!4u3r08.DOC DDIABLO CANYON- UNITS 1 & 2 Rev SA Page 36 of 108 Tab B3!4u3r08.DO C. ________________________ 0121 .064a nnm * *

• n* n * * * * * * *
• n.Cn_mCnC*mnn**n * * *n //::A Deleted' 0919,1043 1.1-1

RCS Loops - MODE 5, Loops Not Filled B 3.4.8 BASES LCO An OPERABLE RHR loop is comprised of an OPERABLE RHR pump (continued) capable of providing forced flow to an OPERABLE RHR heat exchanger. RHR pumps are OPERABLE if they are capable of being powered and are able to provide flow if required. Management of gas voids is important to RHR System OPERABILITY. APPLICABILITY In MODE 5 with loops not filled, this LCO requires core heat removal and coolant circulation by the RHR System. The "loops filled" condition requires that the RCS is capable of being pressurized to at least 150 psig, no gas has been directly injected into the RCS, and the RCS has not been drained to below 112ft (Ref. 1). Loops filled is based on the ability to credit natural circulation as a backup means of decay heat removal, and until the above conditions are met, the "loops not filled" condition is applicable. Operation in other MODES is covered by: LCO 3.4.4, "RCS Loops- MODES 1 and 2"; LCO 3.4.5, "RCS Loops - MODE 3"; LCO 3.4.6, "RCS Loops - MODE 4"; LCO 3.4.7, "RCS Loops- MODE 5, Loops Filled"; LCO 3.9.5, "Residual Heat Removal (RHR) and Coolant Circulation-High Water Level" (MODE 6); and LCO 3.9.6, "Residual Heat Removal (RHR) and Coolant Circulation-Low Water Level" (MODE 6). Since LCO 3.4.8 contains Required Actions with immediate Completion Times, it is not permitted to enter LCO 3.4.8 from either LCO 3.4.7, "RCS Loops - MODE 5, Loops Filled" or from MODE 6 unless the requirements of LCO 3.4.8 are met. ACTIONS A.1 If only one RHR loop is OPERABLE and in operation , redundancy for RHR is lost. Action must be initiated to restore a second loop to OPERABLE status. The immediate Completion Time reflects the importance of maintaining the availability of two paths for heat removal. (continued) DDIABLO CANYON- UNITS 1 & 2 Rev 8A Page 38 of 108 B3.4.x.DOCTal3 B3!4~::~3r08 . DOC 0120.16270919.104 d 1.1-1

RCS Loops - MODE 5, Loops Not Filled B 3.4.8 BASES ACTIONS B.1 and B.2 (continued) If no required RHR loops are OPERABLE or in operation, except during conditions permitted by Note 1, all operations involving introduction of coolant into the RCS with boron concentration less than required to meet the minimum SDM of LCO 3.1.1 must be suspended and action must be initiated immediately to restore an RHR loop to OPERABLE status and operation. Boron dilution requires forced circulation from at least one RHR pump for proper mixing so that inadvertent criticality can be prevented. Suspending the introduction of coolant into the RCS with boron concentration less than required to meet the minimum SDM of LCO 3.1.1 is required to assure continued safe operation. With coolant added without forced circulation, unmixed coolant could be introduced to the core, however coolant added with boron concentration meeting the minimum SDM maintains acceptable margin to subcritical operations. The immediate Completion Time reflects the importance of maintaining operation for heat removal. The action to restore must continue until one loop is restored to OPERABLE status and operation. SURVEILLANCE SR 3.4.8.1 REQUIREMENTS This SR requires verification that one loop is in operation. Verification may include flow rate, temperature, or pump status monitoring, which help ensure that forced flow is providing heat removal. The Surveillance Frequency is based on operating experience, equipment reliability, and plant risk and is controlled under the Surveillance

• Frequency Control Program.

SR 3.4.8.2 Verification that the required number of pumps are OPERABLE ensures that additional pumps can be placed in operation, if needed, to maintain decay heat removal and reactor coolant circulation. Verification is performed by verifying proper breaker alignment and power available to the required pumps. The Surveillance Frequency is based on operating experience, equipment reliability, and plant risk and is controlled under the Surveillance Frequency Control Program. SR 3.4 .8.3 - - ---------- - -------- - ----- ---- ------- - -- - - - - -i..._F_o_rm _a_tt _e_d_: u _ n_d_er_lin_e_ _ _ _ _ ______, RHR System piping and components have the potential to develop voids and pockets of entrained gases . Preventing and managing gas intrusion and accumulation is necessary for proper operation of the RHR loops and may also prevent water hammer. pump cavitation . and pumping of noncondensible gas into the reactor vessel. Selection of RHR System locations susceptible to gas accumulation is based on a review of system design information . including piping and instrumentation drawings. isometric drawings . plan and elevation drawings and calculations . The design review is supplemented by system walk downs to validate the system high po ints and to confirm DDIABLO CANYON- UNITS 1 & 2 Rev 8A Page 39 of 108 B3.4.x.DOCTab B3!4u3rmlDOC 0120.16270919.1043 1.1-1

RCS Loops- MODE 5, Loops Not Filled B 3.4.8 system walk downs to validate the system high points and to confirm the location and orientation of important components that can become_ sources of gas or could otherwise cause gas to be trapped or difficult to remove during system maintenance or restoration. Susceptible locations depend on plant and system configuration, such as stand-by versus operating conditions . The RHR System is OPERABLE when it is sufficiently filled with water. Acceptance criteria are established for the volume of accumulated gas at susceptible locations. If accumulated gas is discovered that exceeds the acceptance criteria for the susceptible location (or the volume of accumulated gas at one or more susceptible locations exceeds an acceptance criteria for gas volume at the suction or discharge of a pump), the Surveillance is not met. If it is determined by subsequent evaluation that the RHR System is not rendered inoperable by the accumulated gas (i.e., the system is sufficiently filled with water) , the Surveillance may be declared met. Accumulated gas should be eliminated or brought within the acceptance criteria limits. RHR System locations susceptible to gas accumulation are monitored and, if gas is found , the gas volume is compared to the acceptance criteria for the location . Susceptible locations in the same system flow path which are subject to the same gas intrusion mechanisms may be verified by monitoring a representative sub-set of susceptible locations. Monitoring may not be practical for locations that are inaccessible due to radiological or environmental conditions , the plant configuration, or personnel safety. For these locations alternative methods (e.g ., operating parameters , remote monitoring) may be used to monitor the susceptible location . Monitoring is not required for susceptible locations where the maximum potential accumulated gas void volume has been evaluated and determ ined to not challenge system OPERABILITY. The accuracy of the method used for monitoring the susceptible locations and trend ing of the results should be sufficient to assure system OPERABILITY during the Surveillance interval. The Surveillance Frequency is controlled under the Surveillance Frequency Control Program . The Surveillance Frequency may vary by location susceptible to gas accumulation. REFERENCES 1. AR A0582812. 2 . LAR 16-01 Application to Revise Technical Specifications to Adopt TSTF-523 , "Generic Letter 2008-01, Managing Gas Accumulation ," Using the Consolidated Line Item Improvement Process.

                                                                                                     ,{ Deleted: Tab_B3!4u3rDB.DOC DDIABLO CANYON- UNITS 1 & 2 Rev SA Page 40 of 108 Tab B3f4u3r08. DO C. __________________________ 0121 .064a 1.1-1

ECCS - Operating B 3.5.2 BASES (continued) LCO In MODES 1, 2, and 3, two independent (and redundant) ECCS trains are required to ensure that sufficient ECCS flow is available, assuming a single failure affecting either train. Additionally, individual components within the ECCS trains may be called upon to mitigate the consequences of other transients and accidents. In MODES 1, 2, and 3, an ECCS train consists of a centrifugal charging subsystem, an Sl subsystem, and an RHR subsystem . Each train includes the piping, instruments, and controls to ensure an OPERABLE flow path capable of taking suction from the RWST upon an Sl signal. During an event requiring ECCS actuation, a flow path is required to provide an abundant supply of water from the RWST to the RCS via the ECCS pumps and their respective supply headers to each of the four cold legs. The ECCS suction is manually transferred to the containment recirculation sump to place the system in the recirculation mode of operation to supply its flow to the RCS hot and cold legs. During the recirculation operation, the RHR pumps provide suction to the charging and Sl pumps. Management of gas voids is important to ECCS OPERABILITY. The containment recirculation sump is considered OPERABLE when all the following conditions are met:

• All strainer disks are bolted in or blanks are installed .
• No structural distress that could impair strainer/trash rack function .
• Covers to all 13 access ports to the strainer system are installed.
• The two expansion joints connecting the rear strainer plenums to the pipe structure are intact.
• Lower plenum drain valve (SI-1-294 for Unit 1 or Sl-2-295 for Unit 2) is closed, or the pipe cap or inlet strainer (STR-440) is installed .

During recirculation operation, the flow path for each train must maintain its designed independence to ensure that no single failure can disable both ECCS trains. (continued) DIABLO CANYON -UNITS 1 & 2 Rev SA Page 13 of 39 Tab_B3!5u3r08.DOC 0120.16300919.1002 1.1-1

ECCS - Operating B 3.5.2 BASES SURVEILLANCE SR 3.5.2.2 (continued) REQUIREMENTS The Surveillance Frequency is based on operating experience, equipment reliability, and plant risk and is controlled under the Surveillance Frequency Control Program . The Surveillance is modified by a Note which exempts system vent flow paths opened under administrative control. The administrative control should be proceduralized and include stationing a dedicated individual at the system vent flow path who is in continuous communication with the operators in the control room . This individual will have a method to rapidly close the system vent flow path if directed. SR 3.5.2.3 ECCS piping and components have the VVith the exception of the operating GGP, the EGGS pumps are normally in a standby, nonoperating mode. As such , flow path piping has the potential to develop voids and pockets of entrained gases. Preventing and managing gas intrusion and accumulation is necessary for -proper operation of the ECCS and may also Maintaining the piping from the EGGS pumps to the RGS full of 'Nater ensures that the system 'Nil I perform properly, injecting its full capacity into the RGS upon demand. This will also prevent water hammer, pump cavitation, gas binding, and pumping of non-condensable gas (e.g. , air, nitrogen , or hydrogen) into the reactor vessel following an Sl signal or during shutdown oooling . Selection of ECCS locations susceptible to gas accumulation is based on a review of system design information, including piping and instrumentation drawings, isometric drawings. plan and elevation drawings . and calculations. The design review is supplemented by system walk downs to validate the system high points and to confirm the location and orientation of important components that can become sources of gas or could otherwise cause gas to be trapped or difficult to remove during system maintenance or restoration . Susceptible locations depend on plant and system configuration . such as stand-by versus operating conditions. The ECCS is OPERABLE when it is sufficiently filled with water. Acceptance criteria are established for the volume of accumulated gas at susceptible locations. If accumulated gas is discovered that exceeds the acceptance criteria for the susceptible location (or the volume of accumulated gas at one or more susceptible locations exceeds an acceptance criteria for gas volume at the suction or discharge of a pump) the Surveillance is not met. If it is determined by subsequent evaluation that the ECCS is not rendered inoperable by the accumulated gas (i.e .. the system is sufficiently filled with water), the Surveillance may be declared met. Accumulated gas should be eliminated or brought within the acceptance criteria limits. DIABLO CANYON- UNITS 1 & 2 Rev 8A Page 19 of 39 Tab_B3!5u3r08. DOC 0120.16300919.1002 1.1-1

ECCS - Operating B 3.5.2 ECCS locations susceptible to gas accumulation are monitored and . if gas is found. the gas volume is compared to the acceptance criteria for the location . Susceptible locations in the same system flow path which are subject to the same gas intrusion mechanisms may be verified by monitoring a representative sub-set of susceptible locations. Monitoring may not be practical for locations that are inaccessible due to radiological or environmental cond itions . the plant configuration . or personnel safety. For these locations alternative methods (e.g ., operating parameters. remote monitoring) may be used to monitor the susceptible location. Monitoring is not required for susceptible locations where the maximum potential accumulated gas void volume has been evaluated and determined to not challenge system OPERABILITY. The accuracy of the method used for monitoring the susceptible locations and trending of the results should be sufficient to assure system OPERABILITY during the Surveillance interval. The Surveillance Frequency is based on operating experience, equipment reliability, and plant risk and is controlled under the Surveillance Frequency Control Program. The Surveillance Frequency may vary by location susceptible to gas accumulation. The intent of the SR is to assure the ECCS piping is adequately vented. Different means of verification, as alternates to venting the accessible system high points, can be employed to provide this assurance, such as ultrasonic testing the vent lines of the ECCS pump casings and accessible high point vents. SR 3.5.2.4 Periodic surveillance testing of ECCS pumps to detect gross degradation caused by impeller structural damage or other hydraulic component problems is required by the ASME Code. (Ref. 8) This type of testing may be accomplished by measuring the pump developed head at only one point of the pump characteristic curve. This verifies both that the measured performance is within an acceptable tolerance of the original pump baseline performance and that the performance at the test flow is within the performance assumed in the plant safety analysis. SRs are specified in the applicable portions of the lnservice Testing Program, which encompasses Subsection ISTB of the ASME Code for Operation and Maintenance of Nuclear Power Plants. (Ref. 8). This section of the ASME Code provides the activities and frequencies necessary to satisfy the requirements. The following ECCS pumps are required to develop the indicated differential pressure when tested on recirculation flow: CCP ~ 2400 psid Sl pump~ 1455 psid RHR pump~ 165 psid (continued) DIABLO CANYON- UNITS 1 & 2 Rev SA Page 20 of 39 Tab_B3!5u3r08. DOC 0120.16300919.1002 1.1-1

ECCS - Operating B 3.5.2 BASES REFERENCES 1. 10 CFR 50, Appendix A, GDC 35.

2. 10 CFR 50.46.

3. FSAR, Sections 6.3 and 7.3.

4. FSAR, Chapter 15, "Accident Analysis ."

5. NRC Memorandum to V. Stello, Jr., from R.L. Baer, "Recommended Interim Revisions to LCOs for ECCS Components," December 1, 1975.

6. IE Information Notice No. 87-01.

7. BTP EICSB-18, Application of the Single Failure Criteria to Manually-Controlled Electrically-Operated Valves.

8. ASME Code for Operation and Maintenance of Nuclear Power Plants, 2001 Edition including 2002 and 2003 Addenda .

9. Design Changes DCP C-49857 (Unit 1), DCP C-50857 (Unit 2).

j_Q,_License Amendment 202/203, December 31, 2008. 11 . LAR 16-01 Application to Revise Technical Specifications to Adopt TSTF-523. "Generic Letter 2008-01 . Managing Gas Accumulation, " Using the Consolidated Line Item Improvement Process.

                                                                                                                          ) Deleted: 0919.1002 DIABLO CANYON - UNITS 1 & 2                                                                                             

Rev SA Page 22 of 39 / Tab_B3 !5u3r08. DOC 0121 .065E; _______________________________________________________________________________ ___ / 1.1-1

ECCS - Shutdown B 3.5.3 BASES (continued) LCO In MODE 4, one of the two independent (and redundant) ECCS trains (as defined for MODE 4) is required to be OPERABLE to ensure that sufficient ECCS flow is available to the core following a DBA. In MODE 4, an ECCS train consists of a centrifugal charging subsystem and an RHR subsystem. Each train includes the piping, instruments, and controls to ensure an OPERABLE flow path capable of taking suction from the RWST and transferring suction to the containment recirculation sump. The containment recirculation sump is considered OPERABLE when all the following conditions are met:

• All strainer disks are bolted in or blanks are installed.
• No structural distress that could impair strainer/trash rack function.
• Covers to all 13 access ports to the strainer system are installed.
• The two expansion joints connecting the rear strainer plenums to the pipe structure are intact.
• Lower plenum drain valve (SI-1-294 for Unit 1 or Sl-2-295 for Unit 2) is closed, or the pipe cap or inlet strainer (STR-440) is installed.

During an event requiring ECCS actuation, a flow path is required to provide an abundant supply of water from the RWST to the RCS via the ECCS charging and RHR pumps and their respective supply headers to each of the four cold legs. In the long term , this flow path may be switched to take its supply from the containment recirculation sump and to deliver its flow to the RCS hot and cold legs. Management of gas voids is important to ECCS OPERABILITY. This LCO is modified by a Note that allows an RHR train to be considered OPERABLE during system alignment and operation for decay heat removal, if capable of being manually realigned (remote or local) to the ECCS mode of operation and not otherwise inoperable. This allows operation in the RHR mode during MODE 4. (continued) DIABLO CANYON- UNITS 1 & 2 Rev 8A Page 24 of 39 Tab_B3!5u3r08.DOC 0120.16300919.1002 1.1-1

ECCS - Shutdown B 3.5.3 BASES ACTIONS A.1 (continued) With both RHR pumps and heat exchangers inoperable, it would be unwise to require the plant to go to MODE 5, where the only available heat removal system is the RHR. Therefore, the appropriate action is to initiate measures to restore one ECCS RHR subsystem and to continue the actions until the subsystem is restored to OPERABLE status. Opening the containment recirculation sump strainer system access ports, or lower plenum drain valve (SI-1-294 for Unit 1 or Sl-2-295 for Unit 2) without pipe cap or inlet strainer (STR-440) installed, in MODE 4 is considered to be a condition which is outside the accident analysis. Therefore, LCO 3.0.3 must be immediately entered. lU. With no ECCS centrifugal charging subsystem OPERABLE, due to the inoperability of the centrifugal charging pump or flow path from the RWST, the plant is not prepared to provide high pressure response to Design Basis Events requiring Sl. The 1 hour Completion Time to restore at least one ECCS centrifugal charging subsystem to OPERABLE status ensures that prompt action is taken to provide the required cooling capacity or to initiate actions to place the plant in MODE 5, where an ECCS train is not required .

                       .Q.,1 When the Required Actions of Condition B cannot be completed within the required Completion Time, a controlled shutdown should be initiated. Twenty-four hours is a reasonable time, based on operating experience, to reach MODE 5 in an orderly manner and without challenging plant systems or operators.

SURVEILLANCE SR 3.5.3.1 REQUIREMENTS The applicable Surveillance descriptions from Bases 3.5.2 apply. REFERENCES 1. Abnormal Response Guideline, ARG- 2, Rev. 0, Feb. 28, 1992. Note: The applicable references from BASES 3.5.2 apply.

2. LAR 16-01 Application to Revise Technical Specifications to Adopt TSTF-523. "Generic Letter 2008-01 . Managing Gas Accumulation. " Using the Consolidated Line Item Improvement Process.

DIABLO CANYON- UNITS 1 & 2 Rev 8A Page 26 of 39

• I Tab_B3!5u3r08.DOC 012 1.0656.

1.1-1

Containment Spray and Cooling Systems B 3.6.6 BASES APPLICABLE sequenced loading of equipment, containment spray pump startup, and SAFETY spray line filling (Ref. 4). The CFCUs performance for post accident ANALYSES conditions is given in Reference 4. The result of the analysis is that (continued) each train (two CFCUs) combined with one train of containment spray can provide 100% of the required peak cooling capacity during the post accident condition. The modeled Containment Cooling System actuation from the containment analysis is based upon a response time associated with exceeding the containment High-High pressure setpoint to achieving full Containment Cooling System air and safety grade cooling water flow. The Containment Cooling System total response time includes signal delay, DG startup (for loss of offsite power), and component cooling water pump startup times. The Containment Spray System and the Containment Cooling System satisfies Criterion 3 of 10CFR50.36(c)(2)(ii). LCO During a DBA LOCA, a minimum of two CFCUs and one containment spray train are required to maintain the containment peak pressure and temperature below the design limits (Refs. 4). Additionally, one containment spray train is also required to remove iodine from the containment atmosphere and maintain concentrations below those assumed in the safety analysis. To ensure that these requirements are met, two containment spray trains and the CFCU system consisting of four CFCUs or three CFCUs each supplied by a different vital bus must be OPERABLE. Therefore, in the event of an accident, at least one train of containment spray and two CFCUs operate, assuming the worst case single active failure occurs. Each Containment Spray train typically includes a spray pump, spray headers, nozzles, valves, piping, instruments, and controls to ensure an OPERABLE flow path capable of taking suction from the RWST upon an ESF actuation signal. Upon actuation of the RWST Low-Low alarm, the containment spray pumps are secured . Containment spray could then be supplied as required by an RHR pump taking suction from the containment sump. Management of gas voids is important to Containment Spray System OPERABILITY. Each CFCU includes cooling coils, dampers, fans, instruments, and controls to ensure an OPERABLE flow path. APPLICABILITY In MODES 1, 2, 3, and 4, a DBA could cause a release of radioactive material to containment and an increase in containment pressure and temperature requiring the operation of the containment spray trains and CFCUs. In MODES 5 and 6, the probability and consequences of these events are reduced due to the pressure and temperature limitations of these MODES. Thus, the Containment Spray System and the Containment Cooling System are not required to be OPERABLE in MODES 5 and 6.

                                                                                                                                  ,.{ Deleted: Tab_B3!6u3r08.DOC (continued)        ,'*,:,:'..{ Deleted: 1007.1502 DIABLO CANYON -UNITS 1 & 2                                                                                                           ...___ _ _ _ _ _ _ _ _       _..J Rev 8C Page 38 of 53                                                                                                     :?

1~9?_1§. _____________________________________________________________________ ~- ----------/ Tab B3!6u3r08. DO C, ___ Q1_?_ 1.1-1

Containment Spray and Cooling Systems B 3.6.6 BASES (continued) SURVEILLANCE SR 3.6.6.1 REQUIREMENTS Verifying the correct alignment for manual, power operated, and automatic valves in the containment spray flow path provides assurance that the proper flow paths will exist for Containment Spray System operation. The containment spray flow path consists of the direct flow path from the fluid source (e.g., RWST) to the supplied safety-related component (e.g., spray headers) and portions of any branch line flow path off the direct flow path that a valve misposition could result in degradation of the system safety function. This SR does not apply to valves that are locked, sealed, or otherwise secured in position, since these were verified to be in the correct position prior to locking, sealing, or securing. This SR also does not apply to valves which are closed and secured by a cap or blind flange (e.g., manual test, vent, and drain valves), to valves that cannot be inadvertently misaligned (e.g., check valves), or to valves in instrument or sample lines. This SR does not require any testing or valve manipulation . Rather, it involves verification, through a system walkdown, which may include the use of local or remove indicators, that those valves outside containment (only check valves are inside containment) and capable of potentially being mispositioned are in the correct position . The Surveillance Frequency is based on operating experience, equipment reliability, and plant risk and is controlled under the Surveillance Frequency Control Program. The Surveillance is modified by a Note which exempts system vent flow paths opened under administrative control. The administrative control should be proceduralized and include stationing a dedicated individual at the system vent flow path who is in continuous communication with the operators in the control room . This individual will have a method to rapidly close the system vent flow path if directed. SR 3.6.6.2 Operating each required CFCU for;:::: 15 minutes ensures that all trains are OPERABLE and that all associated controls are functioning properly. It also ensures that blockage, fan or motor failure, or excessive vibration can be detected for corrective action . The Surveillance Frequency is based on operating experience, equipment reliability, and plant risk and is controlled under the Surveillance Frequency Control Program. SR 3.6.6.3 Verifying that each required CFCU is receiving the required component cooling water flow of;:::: 1650 gpm provides assurance that the design flow rate assumed in the safety analyses will be achieved (Ref. 4). The component cooling water (CCW) system is hydraulically balanced during normal operation to ensure that at least 1650 gpm is delivered to * ,{ Deleted: Tab_B3!6u3ros.ooc each CFCU during a design bases event (DBA). The hydraulic system ,':::',',':A Deleted: 1oo7.1soz DIABLO CANYON -UNITS 1 & 2 '--------------------> Rev 8C 'Page 42 of 53 _ , Tab B3!6u3r08.DOC. ___ Q1_2_1 ~9X~~ --------------------------------------------------------------------------------- /* 1.1-1

Containment Spray and Cooling Systems B 3.6.6 BASES SURVEILLANCE SR 3.6.6.3 (continued) REQUIREMENTS Operation of the CFCUs is permitted with lower CCW flow to the CFCUs during ASME Section XI testing or decay heat removal in MODE 4 with the residual heat removal heat exchangers in service. To support this conclusion, a calculation was performed to evaluate containment heat removal with one train of containment spray OPERABLE and reduced CCW flow to three CFCUs. The calculation concluded that this configuration would provide adequate heat removal to ensure that the maximum design pressure of containment was not exceeded during a DBA in MODE 1. This analysis also determined that a single failure could not be tolerated during this condition and still assure that the maximum design pressure of containment would not be exceeded. (Ref. 6) The Surveillance Frequency is based on operating experience, equipment reliability, and plant risk and is controlled under the Surveillance Frequency Control Program. __ .-- { Formatted: No underline

                       ,S_f3__ ~&~ *_4 Containment Spray System piping and components have the potential to develop voids and pockets of entrained gases. Preventing and managing gas intrusion and accumulation is necessary for proper operation of the containment spray trains and may also prevent water hammer and pump cavitation .

Selection of Containment Spray System locations susceptible to gas accumulation is based on a review of system design information, including piping and instrumentation drawings, isometric drawings. plan and elevation drawings, and calculations . The design review is supplemented by system walk downs to validate the system high points and to confirm the location and orientation of important components that can become sources of gas or could otherwise cause gas to be trapped or difficult to remove during system maintenance or restoration . Susceptible locations depend on plant and system configuration . such as stand-by versus operating conditions . The Containment Spray System is OPERABLE when it is sufficiently filled with water. Acceptance criteria are established for the volume of accumulated gas at susceptible locations. If accumulated gas is discovered that exceeds the acceptance criteria for the susceptible location (or the volume of accumulated gas at one or more susceptible locations exceeds an acceptance criteria fo r gas volume at the suction or discharge of a pump) . the Surveillance is not met. If it is determined by subsequent evaluation that the Containment Spray System is not rendered inoperable by the accumulated gas (i.e .. the system is ,.{ Deleted: Tab_B3!6u3roa.ooc sufficiently filled with water) . the Surveillance may be declared met. ,,:',.,';::',*,' ) Deleted: 1oo7.1soz DIABLO CANYON - UNITS 1 & 2 Rev 8C Page 44 of 53 I Tab B3!6u3r08. DOC., 0121 . 07~!i -----------------------------------------------------------------------~-------J 1.1-1

Containment Spray and Cooling Systems B 3.6.6 Accumulated gas should be eliminated or brought within the acceptance criteria limits . Containment Spray System locations susceptible to gas accumulation are monitored and. if gas is found . the gas volume is compared to the acceptance criteria for the location . Susceptible locations in the same system flow path which are subject to the same gas intrusion mechanisms may be verified by monitoring a representative sub-set of susceptible locations. Monitoring may not be practical for locations that are inaccessible due to radiological or environmental conditions. the plant configuration. or personnel safety. For these locations alternative methods (e.g., operating parameters. remote monitoring) may be used to monitor the susceptible location. Monitoring is not required for susceptible locations where the maximum potential accumulated gas void volume has been evaluated and determined to not challenge system OPERABILITY. The accuracy of the method used for monitoring the susceptible locations and trending of the results should be sufficient to assure system OPERABILITY during the Surveillance interval. The Surveillance Frequency is controlled under the Surveillance Frequency Control Program. The Surveillance Frequency may varv by location susceptible to gas accumulation.

.1= --_ _ _ _ _ _ _ ____.~

SR 3.6.6.,f2_____________________________________________________________________________________ .- ---{.__D_e_le_te_d-' Verifying each containment spray pump's developed head at the flow test point is greater than or equal to the required developed head (205 psid) ensures that spray pump performance has not degraded during the cycle. Flow and differential pressure are normal tests of centrifugal pump performance required by the ASME O&M Code (Ref. 5). Since the containment spray pumps cannot be tested with flow through the spray headers, they are tested on recirculation flow. During refueling operation, a containment spray pump can be aligned to take suction from the refueling water storage tank (RWST) and discharge into the residual heat removal system discharge line back to the RWST. Flow using this lineup can achieve full design flow of 2600 gpm. This test confirms one point on the pump design curve and is indicative of overall performance. Such inservice tests confirm component OPERABILITY, trend performance, and detect incipient failures by abnormal performance. The Frequency of the SR is in accordance with the lnservice Testing Program. SR 3.6.6,§_and_~R- ~*~L? .Z ____________________________________________________________ ~---- - - {>=D=e=le=te=d:,;,.§=========<

                                                                                                                         ------{ Deleted:.§ These SRs require verification that each automatic containment spray valve actuates to its correct position and that each containment spray pump starts upon receipt of an actual or simulated actuation of a containment high-high pressure signal with a coincident "S" signal.                                        ,( Deleted: Tab_B3!6u3r08.DOC
              ... .. . . This Surveillance is not required for valves that are locked, sealed, or
                                                                                                                              ',',*:A Deleted: 1007.1502 DIABLO CANYON- UNITS 1 & 2                                                                                                   

Rev 8C Page 45 of 53  :/ Tab B3!6u3r08.DO<; Q}_?1_ ~074_§. ___________________________ __ ______________________________________________ ___ ___ / 1.1 -1

Containment Spray and Cooling Systems B 3.6.6 BASES SURVEILLANCE SR 3.6.6,§___________________________________________________________________________________ ___ - -- {'---o_e_le_te_d----':= z -------------' REQUIREMENTS This SR requires verification that each CFCU actuates upon receipt of (continued) an actual or simulated safety injection signal. The Surveillance Frequency is based on operating experience, equipment reliability, and plant risk and is controlled under the Surveillance Frequency Control Program. SR 3.6.6..@ ___________________________________________________________________ ----1 Deleted: .§

                                                                                                                                                           ~-----------~

With the containment spray inlet valves closed and the spray header drained of any solution, low pressure air or smoke can be blown through test connections. This SR ensures that each spray nozzle is unobstructed and provides assurance that spray coverage of the containment during an accident is not degraded. The Surveillance Frequency is based on operating experience, equipment reliability, and plant risk and is controlled under the Surveillance Frequency Control Program. SR 3.6.6 10 _/-- { Deleted:~

                     .=..:....:c........=....:..=;..:...=.~
                                                          'f ~- ------------------------------------------------------------------------------- - -        "-------------~

The CFCUs are designed to start or restart in low speed upon receipt of an Sl signal. This SR ensures that this feature is functioning properly. The Surveillance Frequency is based on operating experience, equipment reliabil ity, and plant risk and is controlled under the Surveillance Frequency Control Program. REFERENCES 1. FSAR, Appendix 3.1A

2. 10 CFR 50, Appendix K.

3. FSAR, Section 6.2.1.

4. FSAR, Section 6.2.2.

5. ASME Code for Operation and Maintenance of Nuclear Power Plants, 2001 Edition including 2002 and 2003 Addenda.

6. License Amendment 89/88, April 16, 1996.

7. Calculation STA-075, "Minimum ECCS Flow and Minimum Recirculation Spray Flow During the Sump Recirculation Phases."

8. License Amendment 202/203, December 31, 2008.

9. LAR 16-01 Application to Revise Technical Specifications to Adopt TSTF-523, "Generic Letter 2008-01, Managing Gas Accumulation ,"

Using the Consolidated Line Item Improvement Process. e , *. ***

                                                                                                                                                         ,{ Deleted: Tab_83!6u3rOB.DOC
                                                                                                                                                  , / ;)    Deleted* 1007.1502 DIABLO CANYON- UNITS 1 & 2 Rev 8C Page 47 of 53 Tab B3!6u3r08.Doc; ___ _Q121 ._ 9X1~                              -------------------------------------- ________________________________________ ./

1.1-1

RHR arid Coolant Circulation - High Water Level B 3.9.5 BASES LCO b. Mixing of borated coolant to minimize the possibility of criticality; (continued) and

c. Indication of reactor coolant temperature.

An OPERABLE RHR loop includes an RHR pump, a heat exchanger, valves, piping, instruments, and controls to ensure an OPERABLE flow path and to determine the low end temperature. The flow path starts in one of the RCS hot legs and is returned to the RCS cold legs. Management of gas voids is important to RHR System OPERABILITY. The LCO is modified by a Note that allows the required operating RHR loop to be removed from service for up to 1 hour per 8 hour period, provided no operations are permitted that would dilute the RCS boron concentration with coolant at boron concentrations less than required to meet the minimum boron concentration of LCO 3.9.1. Boron concentration reduction with coolant at boron concentrations less than required to assure the minimum required RCS boron concentration is maintained is prohibited because uniform concentration distribution cannot be ensured without forced circulation. This permits operations such as valve testing, core mapping, or alterations in the vicinity of the reactor vessel hot leg nozzles. During this 1 hour period, decay heat is removed by natural convection to the large mass of water in the refueling cavity. The LCO is also modified by a second Note that allows the required RHR Loop to be removed from service for up to 2 hours per 8 hour period to support surveillance leak rate testing of the RCS to RHR suction isolation valves, provided that no operations are permitted which might result in reduction of boron concentration. During this 2 hour period, decay heat is removed by natural convection to the large mass of water in the refueling cavity and the RCS . APPLICABILITY One RHR loop must be OPERABLE and in operation in MODE 6, with the water level 2 23 ft above the top of the reactor vessel flange, to provide decay heat removal. The 23 ft water level was selected because it corresponds to the 23 ft requirement established for fuel movement in LCO 3.9.7, "Refueling Cavity Water Level." Requirements for the RHR System in other MODES are covered by LCOs in Section 3.4, Reactor Coolant System (RCS), and Section 3.5, Emergency Core Cooling Systems (ECCS). RHR loop requirements in MODE 6 with the water level< 23ft are located in LCO 3.9.6, "Residual Heat Removal (RHR) and Coolant Circulation-Low Water Level." (continued)

                                                                                                                              ,{ Deleted: Tab_B3!9u3r08.DOC
                                                                                                                           /,{ Deleted: 0206.0612 DIABLO CANYON - UNITS 1 & 2                                                                                           ,,,',.;/

Rev SA Page 18 of 28 Tab B3!9u3r08. DO G. 0121 .0754. _________________________________________________________________________ ________ / 1.1-1

RHR and Coolant Circulation- High Water Level B 3.9.5 BASES (continued) SURVEILLANCE SR 3.9.5.1 REQUIREMENTS This Surveillance demonstrates that the RHR loop is in operation and circulating reactor coolant. The flow rate of 3000 gpm is determ ined by the flow rate necessary to provide sufficient decay heat removal capability and to prevent thermal and boron stratification in the core prior to 57 hours of core subcriticality. The second part of this Surveillance serves the same function but with 57 hours or more of core subcriticality. The flow rate of 1300 gpm is determined by the flow rate necessary to provide sufficient decay heat removal capability and to prevent thermal and boron stratification in the core. Both of these flow rates are points of the same flow rate verses decay heat. The Surveillance Frequency is based on operating experience, equipment reliability, and plant risk and is controlled under the Surveillance Frequency Control Program . SR 3.9.5.2 RHR System piping and components have the potential to develop voids and pockets of entrained gases. Preventing and managing gas intrusion and accumulation is necessary for proper operation of the RHR loops and may also prevent water hammer. pump cavitation. and pumping of noncondensible gas into the reactor vessel. Selection of RHR System locations susceptible to gas accumulation is based on a review of system design information . including piping and instrumentation drawings. isometric drawings. plan and elevation drawings . and calculations. The design review is supplemented by system walk downs to validate the system high points and to confirm the location and orientation of important components that can become sources of gas or could otherwise cause gas to be trapped or difficult to remove during system maintenance or restoration . Susceptible locations depend on plant and system configuration , such as stand-by versus operating conditions . The RHR System is OPERABLE when it is sufficiently filled with water. Acceptance criteria are established for the volume of accumulated gas at susceptible locations. If accumulated gas is discovered that exceeds the acceptance criteria for the susceptible location (or the volume of accumulated gas at one or more susceptible locations exceeds an acceptance criteria for gas volume at the suction or discharge of a pump). the Surveillance is not met. If it is determined by subsequent evaluation that the RHR System is not rendered inoperable by the accumulated gas (i.e .. the system is sufficiently filled with water) . the Surveillance may be declared met. Accumulated gas should be eliminated or brought within the acceptance criteria limits.

                                                                                                                                   ,{ Deleted: Tab_B3!9u3r08.DOC RHR System locations susceptible to gas accumulation are monitored                                          ,{
                                                                                                                              ',','>  Deleted: 0206 .0612 DIABLO CANYON- UNITS 1 & 2                                                                                                  

Rev 8A Page 20 of 28  :/ Tab B3!9u3r08. DO C. ___ 0121 .0754_ _______________________________________________________________________ __________ _/ 1.1-1

RHR and Coolant Circulation - High Water Level B 3.9.5 and, if gas is found , the gas volume is compared to the acceptance criteria for the location . Susceptible locations in the same system flow path which are subject to the same gas intrusion mechanisms may be verified by monitoring a representative sub-set of susceptible locations. Monitoring may not be practical for locations that are inaccessible due to radiological or environmental conditions. the plant configuration. or personnel safety. For these locations alternative methods (e.g., operating parameters . remote monitoring) may be used to monitor the susceptible location . Monitoring is not required for susceptible locations where the maximum potential accumulated gas void volume has been evaluated and determined to not challenge system OPERABILITY. The accuracy of the method used for monitoring the susceptible locations and trending of the results should be sufficient to assure system OPERABILITY during the Surveillance interval. The Surveil lance Frequency is controlled under the Surveillance Frequency Control Program . The Surveillance Frequency may vary by location susceptible to gas accumulation . REFERENCES 1. FSAR Section 5.5.7. I

2. License Amendment 28/27 January 5 1988.

1 1

                                                                                                                         +------ -{ Formatted Table

3. LAR 16-01 Application to Revise Technical Specifications to Adopt TSTF-523 "Generic Letter 2008-01 Managing Gas I Accumulation ," Using the Consolidated Line Item Improvement Process.

l Deleted: Tab_B3!9u3r08.DOC

                                                                                                                                 *.*.*:A Deleted: 0206.0612 DIABLO CANYON - UNITS 1 & 2                                                                                                     

Rev SA Page 21 of 28  :/ Tab B3 !9u3r08. DO C. __ Q} 21 .0~5_4.r _______________________ __________________________________________________________ / 1.1-1

RHR and Coolant Circulation- Low Water Level B 3.9.6 BASES LCD An OPERABLE RHR loop consists of an RHR pump, a heat (continued) exchanger, valves, piping, instruments and controls to ensure an OPERABLE flow path and to determine the low end temperature. The flow path starts in one of the RCS hot legs and is returned to the RCS cold legs. Management of gas voids is important to RHR System OPERABILITY. An operable RHR loop must be capable of being realigned to provide an operable flow path. APPLICABILITY Two RHR loops are required to be OPERABLE, and one RHR loop must be in operation in MODE 6, with the water level< 23ft above the top of the reactor vessel flange , to provide decay heat removal. Requirements for the RHR System in other MODES are covered by LCOs in Section 3.4, Reactor Coolant System (RCS), and Section 3.5, Emergency Core Cooling Systems (ECCS). RHR loop requirements in MODE 6 with the water level;:: 23ft are located in LCO 3.9.5, "Residual Heat Removal (RHR) and Coolant Circulation-High Water Level." ACTIONS A.1 and A.2 If less than the required number of RHR loops are OPERABLE, action shall be immediately initiated and continued until the RHR loop is restored to OPERABLE status and to operation or until;:: 23ft of water level is established above the reactor vessel flange. When the water level is ;:: 23 ft above the reactor vessel flange, the Applicability changes to that of LCO 3.9.5, and only one RHR loop is required to be OPERABLE and in operation . An immediate Completion Time is necessary for an operator to initiate corrective actions. liJ. If no RHR loop is in operation, there will be no forced circulation to provide mixing to establish uniform boron concentrations. Suspending positive reactivity additions that could result in failure to meet the minimum boron concentration limit is required to assure continued safe operation . Introduction of coolant inventory must be from sources that have a boron concentration greater than that required in the RCS for minimum refueling boron concentration. This may result in an overall reduction in RCS boron concentration, but provides acceptable margin to maintaining subcritical operation . B.2 If no RHR loop is in operation, actions shall be initiated immediately, and continued , to restore one RHR loop to operation. Since the unit is in Conditions A and B concurrently, the restoration of two OPERABLE RHR loops and one operating RHR loop should be accomplished expeditiously. (continued)

                                                                                                                                 ,{ Deleted: Tab_B3!9u3r08.DOC
                                                                                                                              /,{ Deleted: 0206.0612 DIABLO CANYON - UNITS 1 & 2                                                                                              ,,,',-:/

Rev 8A Page 23 of 28 Tab B3 !9u3r08. DO C,. 0121 .0754. _____________________ ~---- _______________________________________________________ / 1.1-1

RHR and Coolant Circulation- Low Water Level B 3.9.6 BASES ACTIONS B.3 (continued) If no RHR loop is in operation, all containment penetrations providing direct access from the containment atmosphere to the outside atmosphere must be closed within 4 hours. With the RHR loop requirements not met, the potential exists for the coolant to boil and release radioactive gas to the containment atmosphere. Closing containment penetrations that are open to the outside atmosphere ensures that dose limits are not exceeded. The Completion Time of 4 hours is reasonable at water levels above reduced inventory, based on the low probability of the coolant boiling in that time. At reduced inventory conditions or mid-loop operations, additional actions are taken to provide containment closure in a reduced period of time (Ref. 3). Reduced inventory is defined as less than Elev. 111 ft. SURVEILLANCE SR 3.9.6.1 REQUIREMENTS This Surveillance demonstrates that one RHR loop is in operation and circulating reactor coolant. The flow rate of more than 3000 gpm is determined by the flow rate necessary to provide sufficient decay heat removal capability and to prevent thermal and boron stratification in the core prior to 57 hours subcritical. The second part of this Surveillance serves the same function but with 57 hours or more of core subcriticality and provides a reduced flow rate of 1300 gpm based upon a reduced decay heat load. Both of these flow rates are points of the same flow rate verses decay heat curves. The 1300 gpm limit also precludes exceeding the 1675 gpm upper flow limit to prevent vortexing and air entrainment of the RHR piping system. RHR pump vortexing (failure to meet pump suction requirements) during mid-loop operation may result in RHR pump failure and non-conservative RCS level indication. The Surveillance Frequency is based on operating experience, equipment reliability, and plant risk and is controlled under the Surveillance Frequency Control Program . SR 3.9.6.2 Verification that the required pump is OPERABLE ensures that an additional RHR pump can be placed in operation, if needed, to maintain decay heat removal and reactor coolant circulation. Verification is performed by verifying proper breaker alignment and power available to the required pump. The Surveillance Frequency is based on operating experience, equipment reliability, and plant risk and is controlled under the Surveillance Frequency Control Program. SR 3.9.6.3 RHR System piping and components have the potential to develop voids and pockets of entrained gases. Preventing and managing gas intrusion and accumulation is necessary for proper operation of the RHR loops and may also prevent water hammer. pump cavitation . and - ADeleted: Tab_B 3!9 3r0B.DOC U DIABLO CANYON- UNITS 1 & 2 /::'A'-o_e_le_te_d_: o_2_o6_.o_61_2_ _ _ __ ____, Rev SA Page 24 of 28  :? Tab B3!9u3r08.DOC. ___ _Q~_~_t9751 ___________________________________________________________*_____________________ / 1.1 -1

RHR and Coolant Circulation- Low Water Level B 3.9.6 pumping of noncondensible gas into the reactor vessel. Selection of RHR System locations susceptible to gas accumulation is based on a review of system design information. including piping and instrumentation drawings. isometric drawings. plan and elevation drawings. and calculations. The design review is supplemented by system walk downs to validate the system high points and to confirm the location and orientation of important components that can become sources of gas or could otherwise cause gas to be trapped or difficult to remove during system maintenance or restoration. Susceptible locations depend on plant and system configuration. such as stand-by versus operating conditions . The RHR System is OPERABLE when it is sufficiently filled with water. Acceptance criteria are established for the volume of accumulated gas at susceptible locations. If accumulated gas is discovered that exceeds the acceptance criteria for the susceptible location (or the volume of accumulated gas at one or more susceptible locations exceeds an acceptance criteria for gas volume at the suction or discharge of a pump), the Surveillance is not met. If it is determined by subsequent evaluation that the RHR System is not rendered inoperable by the accumulated gas (i.e .. the system is sufficiently filled with water). the Surveillance may be declared met. Accumulated gas should be eliminated or brought within the acceptance criteria limits. RHR System locations susceptible to gas accumulation are monitored and . if gas is found . the gas volume is compared to the acceptance criteria for the location . Susceptible locations in the same system flow path which are subject to the same gas intrusion mechanisms may be verified by monitoring a representative sub-set of susceptible locations. Monitoring may not be practical for locations that are inaccessible due to radiological or environmental conditions. the plant configuration. or personnel safety. For these locations alternative methods (e.g .. operating parameters. remote monitoring) may be used to monitor the susceptible location . Monitoring is not required for susceptible locations where the maximum potential accumulated gas void volume has been evaluated and determined to not challenge system OPERABILITY. The accuracy of the method used for monitoring the susceptible locations and trending of the results should be sufficient to assure system OPERABILITY during the Surveillance interval. The Surveillance Frequency is controlled under the Surveillance Frequency Control Program . The Surveillance Frequency may vary by location susceptible to gas accumulation. (continued)

                                                                               ,{ Deleted: Tab_B3!9u3r08 .DOC 1.1-1

RHR and Coolant Circulation - Low Water Level B 3.9.6 BASES (continued) REFERENCES 1. FSAR, Section 5.5.7

2. License Amendment 28/27, January 5, 1988.

3. Generic Letter 88-17, "Loss of Decay Heat Removal. "

4. LAR 16-01 Appl ication to Revise Technical Specifications to Adopt TSTF-523, "Generic Letter 2008-01, Managing Gas Accumulation, " Using the Consolidated Line Item Improvement Process.

                                                                                                                                         ,{ Deleted: Tab_B3!9u3r08.DOC 0206 0612 DIABLO CANYON- UNITS 1 & 2                                                                                                             :('_,{ Deleted:     .         - -**--

Rev 8A Page 26 of 28  :? Tab B3 !9 u3r08. DO C. ___ 0 1_? 1.97_ 51 ______________ _____ __ ______________ __ __ ____ ______ ________________________________ / 1.1-1

Pacific Gas .and Electric Company* James M. Welsch Diablo Canyon Power Plant Vice President, Nuclear Generation P.O. Box 56 Avila Beach, CA 93424 805.545.3242 E-Mail: JMWl@pge.com January 21, 2016 PG&E Letter DCL-16-001 U.S. Nuclear Regulatory Commission 10 CFR 50.90 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 16-01, Application to Revise Technical Specifications to Adopt TSTF-523. "Generic Letter 2008-01. Managing Gas Accumulation." Using the Consolidated Line Item Improvement Process

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 Facility Operating License Nos. DPR-80 and DPR-82 for Units 1 and 2 of the Diablo Canyon Power Plant (DCPP), respectively. The enclosed license.amendment request (LAR) proposes to revise Technical Specification (TS) 3.4.6 "RCS Loops- MODE 4," TS 3.4.7 "RCS Loops- MODE 5, Loops Filled," TS 3.4.8. "RCS Loops- MODE 5, Loops Not Filled," TS 3.5.2 "ECCS- Operating," TS 3.6.6 "Containment Spray and Cooling Systems," TS 3.9.5 "RHR and Coolant Circulation- High Water Level," and TS 3.9.6 "RHR and Coolant Circulation- Low Water Level." The proposed amendment would modify TS requirements to address Generic Letter 2008-01, "Managing Gas Accumulation in Emergency Core Cooling, Decay Heat Removal, and Containment Spray Systems," as described in Technical Specification Task Force TSTF-523, Revision 2, "Generic Letter 2008-01, Managing Gas Accumulation." The enclosure provides a description and assessment of the proposed change with three attachments. Attachment 1 provides the existing TS pages marked up to show the proposed change. Attachment 2 provides revised (clean) TS pages. Attachment 3 provides existing TS Bases pages marked to show the proposed change. Changes to the existing TS Bases, consistent with the technical and regulatory analyses, will be implemented under the Technical Specification Bases Control Program. They are provided in Attachment 3 for information only. A member of the STARS (Strategic Teaming and Resource Sharing) Alliance Callaway

• Diablo Canyon
• Palo Verde
• Wolf Creek

Document Control Desk PG&E Letter DCL-16-001 January 21, 2016 Page 2 The changes in this LAR are not required to address an immediate safety concern. PG&E requests approval of this LAR by no later than January 21, 2017. PG&E requests the license amendments to be effective upon NRC issuance of the license amendment, and to be implemented within 120 days from the date of issuance. PG&E makes no new or revised regulatory commitments (as defined by NEI 99-04) in this letter. In accordance with site administrative procedures and the Quality Assurance Program, the proposed amendment has been reviewed by the Plant Staff Review Committee. If you have any questions or require additional information, please contact Mr. Hossein Hamzehee at 805-545-4720. I state under penalty of perjury that the foregoing is true and correct. Executed on January 21, 2016. Sincerely, Jl.__- ,/lA 0dl...t_~ ~:~~~;lsch Vice President, Nuclear Generation aph8/64 70/50037662 Enclosure cc: Diablo Distribution cc/enc: Marc L. Dapas, NRC Region IV Binesh Tharakan, Acting NRC Senior Resident Inspector Siva P. Ling am, NRR Project Manager Gonzalo L. .Perez, Branch Chief, California Department of Public Health A member of the STARS (Strategic Teaming and Resource Sharing) Alliance Callaway

• Diablo Canyon
• Palo Verde
• Wolf Creek

Enclosure PG&E Letter DCL-16-001 Evaluation of the Proposed Change License Amendment Request 16-01 Application to Revise Technical Specifications to Adopt TSTF-523, "Generic Letter 2008-01, Managing Gas Accumulation," Using the Consolidated Line Item Improvement Process

Enclosure PG&E Letter DCL-16-001 Evaluation of the Proposed Change License Amendment Request 16-01 Application to Revise Technical Specifications to Adopt TSTF-523, "Generic Letter 2008-01, Managing Gas Accumulation," Using the Consolidated Line Item Improvement Process

1. DESCRIPTION

2. ASSESSMENT 2.1 Applicability of Published Safety Evaluation 2.2 Optional Changes and Variations

3. REGULATORY ANALYSIS 3.1 No Significant Hazards Consideration Determination

4. ENVIRONMENTAL EVALUATION ATTACHMENTS:

1. Proposed Technical Specification Changes

2. Revised Technical Specification Pages

3. Proposed Technical Specification Bases Changes 1

                                                                         ' Enclosure PG&E Letter DCL-16-001 Evaluation of the Proposed Change

1. DESCRIPTION The proposed change revises or adds Surveillance Requirements to verify that the system locations susceptible to gas accumulation are sufficiently filled with water and to provide allowances which permit performance of the verification.

The changes are being made to address the concerns discussed in Generic Letter 2008-01, "Managing Gas Accumulation in Emergency Core Cooling, Decay Heat Removal, and Containment Spray Systems." The proposed amendment is consistent with Technical Specification Task Force TSTF-523, Revision 2, "Generic Letter 2008-01, Managing Gas Accumulation."

2. ASSESSMENT 2.1 Applicability of Published Safety Evaluation Pacific Gas and Electric (PG&E) has reviewed the model safety evaluation dated January 15, 2014, as part of the Federal Register Notice of Availability. This review included a review of the NRC Staff's evaluation, as well as the information provided in TSTF-523. PG&E has concluded that the justifications presented in the TSTF-523 proposal and the model safety evaluation prepared by the NRC Staff are applicable to Diablo Canyon Units 1 and 2 and justify this amendment for the incorporation of the changes to the Diablo Canyon Technical Specifications (TS).

2.2 Optional Changes and Variations PG&E is not proposing any variations or deviations from the TS changes described in the TSTF-523, Revision 2, or the applicable parts of the NRC staff's model safety evaluation dated January 15, 2014.

3. REGULATORY ANALYSIS 3.1 No Significant Hazards Consideration Determination Pacific Gas and Electric Company (PG&E) requests adoption of TSTF-523, Revision 2, "Generic Letter 2008-01, Managing Gas Accumulation," which is an approved change to the standard technical specifications (STS), for the Diablo Canyon Units 1 and 2 TS. The proposed change revises or adds Surveillance Requirements to verify that the system locations susceptible to gas accumulation are sufficiently filled 2

Enclosure PG&E Letter DCL-16-001 with water and to provide allowances which permit performance of the verification. PG&E has evaluated whether or not 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 change involve a significant increase in the probability or consequences of an accident previously evaluated?

Response: No. The proposed change revises or adds Surveillance R~quirement(s) (SRs) that require verification that the Emergency Core Cooling System (ECCS), the Residual Heat Removal (RHR) System, and the Containment Spray (CS) System are not rendered inoperable due to accumulated gas and to provide allowances which permit performance of the revised verification. Gas accumulation in the s.ubject systems is not an initiator of any accident previously evaluated. As a result, the probability of any accident previously evaluated is not significantly increased. The proposed SRs ensure that the subject systems continue to be capable to perform their assumed safety function and are not rendered inoperable due to gas accumulation. Thus, the consequences of any accident previously evaluated are not significantly increased. Therefore, the proposed change does 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?

Response: No. The proposed change revises or adds SRs that require verification that the ECCS, RHR System, and CS System are not rendered inoperable due to accumulated gas and to provide allowances which permit performance of the revised verification. The proposed 3

Enclosure PG&E Letter DCL-16-001 change does not involve a physical alteration of the plant (i.e., no new or different type of equipment will be installed) or a change in the methods governing normal plant operation. In addition, the proposed change does not impose any new or different requirements that could initiate an accident. The proposed change does not alter assumptions made in the safety analysis and is consistent with the safety analysis assumptions. 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 change involve a significant reduction in a margin of safety?

Response: No. The proposed change revises or adds SRs that require verification that the ECCS, the RHR System, and the CS System are not rendered inoperable due to accumulated gas, and to provide allowances which permit performance of the revised verification. The proposed change adds new requirements to manage gas accumulation in order to ensure the subject systems are capable of performing their assumed safety functions. The proposed SRs are more comprehensive than the current SRs, and will ensure that the assumptions of the safety analysis are protected. The proposed change does not adversely affect any current plant safety margins or the reliability of the equipment assumed in the safety analysis. Therefore, there are no changes being made to any safety analysis assumptions, safety limits, or limiting safety system settings that would adversely affect plant safety as a result of the proposed change. Therefore, the proposed change does not involve a significant reduction in a margin of safety. 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. 4

Enclosure PG&E Letter DCL-16-001

4. ENVIRONMENTAL EVALUATION The proposed change 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 change does not involve (i) a significant hazards consideration, (ii) a significant change in the types or a significant increase in the amounts of any effluent that may be released offsite, or (iii) a significant increase in individual or cumulative occupational radiation exposure. Accordingly, the proposed change 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 change. 5

Enclosure Attachment 1 PG&E Letter DCL-16-001 Proposed Technical Specification Changes

Enclosure Attachment 1 PG&E Letter DCL-16-001 Proposed Technical Specification Changes Add TS Insert 1 to Page 3.4-11 TS Insert 1 SR -------------------------------~()TE:----------------------------- In accordance 3.4.6.4 ~ot required to be performed until 12 hours after with the entering M()DE: 4. Surveillance Frequency Verify required RHR loop locations susceptible to Control Program gas accumulation are sufficiently filled with water. Add TS Insert 2 to Page 3.4-13 TS Insert 2 SR 3.4.7.4 Verify required RHR loop locations susceptible to In accordance gas accumulation are sufficiently filled with water. with the Surveillance Frequency Control Program Add TS Insert 3 to Page 3.4-15 TS Insert 3 SR 3.4.8.3 Verify RHR loop locations susceptible to gas In accordance accumulation are sufficiently filled with water. with the Surveillance Frequency Control Program Add TS Insert 4 to Pages 3.5-4 and 3.6-15 TS Insert 4

                    ---------------------------------~()TE:---------------------------
                    ~ot required to be met for system vent flow paths opened under administrative control.

1

Enclosure Attachment 1 PG&E Letter DCL-16-001 Add TS Insert 5 to Page 3.5-5 TS Insert 5 Verify ECCS locations susceptible to gas accumulation are sufficiently filled with water. Add TS Insert 6 to Page 3.6-15 TS Insert 6 SR 3.6.6.4 Verify containment spray locations susceptible to In accordance gas accumulation are sufficiently filled with water. with the Surveillance Frequency Control Program Add TS Insert 7 to Page 3.9-5 TS Insert 7 SR 3.9.5.2 Verify required RHR loop locations susceptible to In accordance gas accumulation are sufficiently filled with water. with the Surveillance Frequency Control Program Add TS Insert 8 to Page 3.9-7 TS Insert 8 SR 3.9.6.3 Verify RHR loop locations susceptible to gas In accordance accumulation are sufficiently filled with water. with the Surveillance Frequency Control Program 2

RCS Loops - MODE 4 3.4.6 ACTIONS (continued) CONDITION REQUIRED ACTION COMPLETION TIME B. Two required loops B.1 Suspend operations that Immediately inoperable. would cause introduction of coolant into the RCS OR . with boron concentration less than required to meet SDM of LCO 3.1.1. AND No RCS or RHR loop in B.2 Initiate action to restore Immediately operation. one loop to OPERABLE status and operation. SURVEILLANCE REQUIREMENTS SURVEILLANCE FREQUENCY SR 3.4.6.1 Verify one RHR or RCS loop is in operation. In accordance with the Surveillance Frequency Control Program SR 3.4.6.2 Verify SG secondary side water levels are ;: : 15o/o for In accordance with required RCS loops. the Surveillance Frequency Control Program SR 3.4.6.3 Verify correct breaker alignment and indicated power In accordance with are available to the required pump that is not in the Surveillance operation. Frequency Control Program DIABLO CANYON - UNITS 1 & 2 3.4-11 Unit 1 - Amendment No. ~ +42 +M 2-Ge-,. Rev 10 Page 12 of 40 Unit 2 - Amendment No. ~ +42 §9. .f?k)+- Tab_3!4u3r1 O.DOC 0124.1255 '

RCS Loops - MODE 5, Loops Filled 3.4.7 ACTIONS CONDITION REQUIRED ACTION COMPLETION TIME A. One RHR loop inoperable. A.1 Initiate action to restore Immediately a second RHR loop to AND OPERABLE status. OR Required SGs secondary A.2 Initiate action to restore Immediately side water levels not within required SG secondary limits. side water levels to within limits. B. Required RHR loops B.1 Suspend operations that Immediately inoperable. would cause introduction of coolant into the RCS OR with boron concentration less than required to meet SDM of LCO 3.1 .1. AND No RHR loop in operation. B.2 Initiate action to restore Immediately one RH R loop to OPERABLE status and operation. SURVEILLANCE REQUIREMENTS SURVEILLANCE FREQUENCY SR 3.4.7.1 Verify one RHR loop is in operation. In accordance with the Surveillance Frequency Control Program SR 3.4.7.2 Verify SG secondary side water level is;::: 15°/o in In accordance with required SGs. the Surveillance Frequency Control Program SR 3.4.7.3 Verify correct breaker alignment and indicated power In accordance with are available to the required RHR pump that is not in the Surveillance operation. Frequency Control Program DIABLO CANYON - UNITS 1 & 2 3.4-13 Unit 1 - Amendment No. ~ §8 2GB*, Rev 10 Page 14 of 40 Unit 2 - Amendment No. ~ 99- *2-8-f 1 Tab_3!4u3r1 O.DOC 0124.1255

RCS Loops - MODE 5, Loops Not Filled 3.4.8 SURVEILLANCE REQUIREMENTS SURVEILLANCE FREQUENCY f SR 3.4.8.1 Verify one RHR loop is in operation. In accordance with the Surveillance Frequency Control Program t SR 3.4.8.2 Verify correct breaker alignment and indicated power In accordance with are available to the required RHR pump that is not in the Surveillance operation. Frequency Control Program DIABLO CANYON - UNITS 1 & 2 3.4-15 Unit 1 - Amendment No. +Je, 2BB-) Rev 10 Page 16 of 40 Unit 2 -Amendment No. +Je, ~ Tab_3!4u3r1 O.DOC 0124.1255

ECCS- Operating 3.5.2 SURVEILLANCE REQUIREMENTS SURVEILLANCE FREQUENCY f SR 3.5.2.1 Verify the following valves are in the listed position In accordance with with power to the valve operator removed. the Surveillance Frequency Control Number Position Function Program 8703 Closed RHR to RCS Hot Legs 8802A Closed Safety Injection to RCS Hot Legs 88028 Closed Safety Injection to RCS Hot Legs 8809A Open RHR to RCS Cold Legs 88098 Open RHR to RCS Cold Legs 8835 Open Safety Injection to RCS Cold Legs 8974A Open Safety Injection Pump Recirc. to RWST 89748 Open Safety Injection Pump Recirc. to RWST 8976 Open RWST to Safety Injection Pumps 8980 Open RWST to RHR Pumps 8982A Closed Containment Sump to RHR Pumps 89828 Closed Containment Sump to RHR Pumps 8992 Open Spray Additive Tank to Eductor 8701 Closed RHR Suction 8702 Closed RHR Suction SR 3.5.2.2 I*V Verify each ECCS manual, power operated, and automatic valve in the flow path, that is not locked, In accordance with the Surveillance S r* S6\z..:\ 'i sealed, or otherwise secured in position, is in the Frequency Control N

• correct position. Program SR 3.5.2. 3 V-eA.f.y'-E~~~-e.f~-. In accordance with the Surveillance Frequency Control

.!1\J~er!.T 5 Program (continued) ft\v vc. ~ rz. -;. '7. -z_ . .3 7"o PAb-t ~. S- 5 DIABLO CANYON - UNITS 1 & 2 3.5-4 Unit 1 - Amendment No. +&a, ~ ;

Rev 9 Page 4 of 8 Unit 2 - Amendment No. +&a, 2-9~- J Tab_3!5u3r09.DOC 1027.1544

ECCS- Operating 3.5.2 SURVEILLANCE REQUIREMENTS (continued) SURVEILLANCE FREQUENCY SR 3.5.2.4 Verify each ECCS pump's developed head at the test In accordance with flow point is greater than or equal to the required the lnservice developed head. Testing Program. SR 3.5.2.5 Verify each ECCS automatic valve in the flow path In accordance with that is not locked, sealed, or otherwise secured in the Surveillance position, actuates to the correct position on an actual Frequency Control or simulated actuation signal. Program SR 3.5.2.6 Verify each ECCS pump starts automatically on an In accordance with actual or simulated actuation signal. the Surveillance Frequency Control Program SR 3.5.2.7 Verify, for each ECCS throttle valve listed below, In accordance with each mechanical position stop is in the correct the Surveillance position. Frequency Control Program Charging Injection Safety Injection Throttle Valves Throttle Valves 8810A 8822A 88108 88228 8810C 8822C 88100 88220 SR 3.5.2.8 Verify, by visual inspection, each ECCS train In accordance with containment recirculation sump suction inlet is not the Surveillance restricted by debris and the suction inlet trash racks Frequency Control and screens show no evidence of structural distress Program or abnormal corrosion. DIABLO CANYON - UNITS 1 & 2 3.5-5 Unit 1 - Amendment No. +as, 2-e9-, Rev 9 Page 5 of 8 Unit 2 - Amendment No. +as, ~J Tab_3!5u3r09.DOC 1027.1544

Containment Spray and Cooling Systems 3.6.6 SURVEILLANCE REQUIREMENTS SURVEILLANCE FREQUENCY SR 3.6.6.1 \-..Verify each containment spray manual, power In accordance with the operated, and automatic valve in the flow path Surveillance Frequency

'JE\~I t...\ -          that is not locked, sealed, or otherwise secured        Control Program in position is in the correct position.

SR 3.6.6.2 Operate each CFCU for 2::. 15 minutes. In accordance with the Surveillance Frequency Control Program SR 3.6.6.3 Verify component cooling water flow rate to each In accordance with the required CFCU is 2::. 1650 gpm. Surveillance Frequency Control Program

• z..,- lc; SR 3.6.6 ..4_ "'5 Verify each containment spray pump's developed In accordance with the head at the flow test point is greater than or lnservice Testing equal to the required developed head. Program SR 3.6.6.-t \c Verify each automatic containment spray valve in In accordance with the the flow path that is not locked, sealed, or Surveillance Frequency otherwise secured in position, actuates to the Control Program correct position on an actual or simulated actuation signal.

SR 3.6.6.{ *1- Verify each containment spray pump starts In accordance with the automatically on an actual or simulated actuation Surveillance Frequency signal. Control Program SR 3.6.6.( B Verify each CFCU starts automatically on an In accordance with the actual or simulated actuation signal. Surveillance Frequency Control Program SR 3.6.6:A q Verify each spray nozzle is unobstructed. In accordance with the Surveillance Frequency Control Program SR 3.6.6 J.. \0 Verify each CFCU starts on low speed. In accordance with the Surveillance Frequency Control Program DIABLO CANYON - UNITS 1 & 2 3.6-15 Unit 1 - Amendment No. ~' ~e- , Rev 6 Page 15 of 18 Unit 2 - Amendment No. ~, 2-e1* J Tab_3!6u3r06.DOC 0416.1252

RHR and Coolant Circulation- High Water Level 3.9.5 SURVEILLANCE REQUIREMENTS SURVEILLANCE FREQUENCY SR 3.9.5.1 With the reactor subcritical less than 57 hours, In accordance with the verify one RHR loop is in operation and circulating Surveillance reactor coolant at a flow rate of;;::: 3000 gpm, Frequency Control Program With the reactor subcritical for 57 hours or more, In accordance with the verify one RHR loop is in operation and circulating Surveillance reactor coolant at a flow rate of;;::: 1300 gpm. Frequency Control Program DIABLO CANYON - UNITS 1 & 2 3.9-5 Unit 1 - Amendment No. ~' ~ CJ Rev 4 Page 8 of 11 Unit 2 - Amendment No. ~, *2ttr Tab_3!9u3r04.DOC 1027.1628 5

RHR and Coolant Circulation- Low Water Level 3.9.6 SURVEILLANCE REQUIREMENTS SURVEILLANCE FREQUENCY SR 3.9.6 .1 With the reactor subcritical less than 57 hours, In accordance with the verify one RHR loop is in operation and circulating Surveillance reactor coolant at a flow rate of;:::: 3000 gpm, Frequency Control Program In accordance with the With the reactor subcritical for 57 hours or more, Surveillance verify one RHR loop is in operation and circulating Frequency Control reactor coolant at a flow rate of ;: : 1300 gpm. Program SR 3.9.6.2 Verify correct breaker alignment and indicated In accordance with the power available to the required RHR pump that is Surveillance not in operation. Frequency Control Program DIABLO CANYON - UNITS 1 & 2 3.9-7 Unit 1 - Amendment No. ~' ~G-. , Rev 4 Page 10 of 11 Unit 2 - Amendment No. ~' ZG-1* 1 Tab_3!9u3r04.DOC 1027.1628

Enclosure Attachment 2 PG&E Letter DCL-16-001 Revised Technical Specification Pages

Enclosure Attachment 2 PG&E Letter DCL-16-001 Revised Technical Specification Pages Remove Page Insert Page 3.4-11 3.4-11 3.4-13 3.4-13 3.4-15 3.4-15 3.5-4 3.5-4 3.5-5 3.5-5 3.6-15 3.6-15, 3.6-15a 3.9-5 3.9-5 3.9-7 3.9-7

RCS Loops - MODE 4 3.4.6 ACTIONS (continued) CONDITION REQUIRED ACTION COMPLETION TIME B. Two required loops B.1 Suspend operations that Immediately inoperable. would cause introduction of coolant into the RCS OR with boron concentration less than required to meet SDM of LCO 3.1.1. AND No RCS or RHR loop in B.2 Initiate action to restore Immediately operation. one loop to OPERABLE status and operation. SURVEILLANCE REQUIREMENTS SURVEILLANCE FREQUENCY SR 3.4.6.1 Verify one RHR or RCS loop is in operation. In accordance with the Surveillance Frequency Control Program SR 3.4.6.2 Verify SG secondary side water levels are ;::: 15% for In accordance with required RCS loops. the Surveillance Frequency Control Program SR 3.4.6.3 Verify correct breaker alignment and indicated power In accordance with are available to the required pump that is not in the Surveillance operation. Frequency Control Program SR 3.4.6.4 -------------------------------N0 T E------------------------------ In accordance with Not required to be performed until 12 hours after the Surveillance entering MODE 4. Frequency Control Program Verify required RHR loop locations susceptible to gas accumulation are sufficiently filled with water. DIABLO CANYON - UNITS 1 & 2 3.4-11 Unit 1 -Amendment No.~~ W 2-00, Rev 11 Page 12 of 40 Unit 2- Amendment No.~~ -ie9 ~.

RCS Loops - MODE 5, Loops Filled 3.4.7 ACTIONS CONDITION REQUIRED ACTION COMPLETION TIME A. One RHR loop inoperable. A.1 Initiate action to restore Immediately a second RHR loop to AND OPERABLE status. OR Required SGs secondary A.2 Initiate action to restore Immediately side water levels not within required SG secondary limits. side water levels to within limits. B. Required RHR loops B.1 Suspend operations that Immediately inoperable. would cause introduction of coolant into the RCS OR with boron concentration less than required to meetSDM ofLC03.1.1. AND No RHR loop in operation . B.2 Initiate action to restore Immediately one RHR loop to OPERABLE status and operation. SURVEILLANCE REQUIREMENTS SURVEILLANCE FREQUENCY SR 3.4.7.1 Verify one RHR loop is in operation. In accordance with the Surveillance Frequency Control Program SR 3.4.7.2 Verify SG secondary side water level is ; : : 15% in In accordance with required SGs. the Surveillance Frequency Control Program SR 3.4.7.3 Verify correct breaker alignment and indicated power In accordance with are available to the required RHR pump that is not in the Surveillance operation. Frequency Control Program SR 3.4.7.4 Verify required RHR loop locations susceptible to gas In accordance with accumulation are sufficiently filled with water. the Surveillance Frequency Control Program DIABLO CANYON - UNITS 1 & 2 3.4-13 Unit 1 -Amendment No. ~-tag 2-00-, Rev 11 Page 14 of 40 Unit 2 -Amendment No. ~ W W-i,

RCS Loops - MODE 5, Loops Not Filled 3.4.8 SURVEILLANCE REQUIREMENTS SURVEILLANCE FREQUENCY SR 3.4.8.1 Verify one RHR loop is in operation. In accordance with the Surveillance Frequency Control Program SR 3.4.8.2 Verify correct breaker alignment and indicated power In accordance with are available to the required RHR pump that is not in the Surveillance operation. Frequency Control Program SR 3.4.8.3 Verify RHR loop locations susceptible to gas In accordance with accumulation are sufficiently filled with water. the Surveillance Frequency Control Program DIABLO CANYON - UNITS 1 & 2 3.4-15 Unit 1 -Amendment No. ~, 00, Rev 11 Page 16 of 40 Unit 2 -Amendment No. ~ ' 2G-1-,

ECCS - Operating 3.5.2 SURVEILLANCE REQUIREMENTS SURVEILLANCE FREQUENCY SR 3.5.2.1 Verify the following valves are in the listed position In accordance with with power to the valve operator removed. the Surveillance Frequency Control Number Position Function Program 8703 Closed RHR to RCS Hot Legs 8802A Closed Safety Injection to RCS Hot Legs 88028 Closed Safety Injection to RCS Hot Legs 8809A Open RHR to RCS Cold Legs 88098 Open RHR to RCS Cold Legs 8835 Open Safety Injection to RCS Cold Legs 8974A Open Safety Injection Pump Recirc. to RWST 89748 Open Safety Injection Pump Recirc. to RWST 8976 Open RWST to Safety Injection Pumps 8980 Open RWST to RHR Pumps 8982A Closed Containment Sump to RHR Pumps 89828 Closed Containment Sump to RHR Pumps 8992 Open Spray Additive Tank to Eductor 8701 Closed RHR Suction 8702 Closed RHR Suction SR 3.5.2.2 ------------------------------N0 T E--------------------------------- Not required to be met for system vent flow paths opened under administrative control. Verify each ECCS manual , power operated, and In accordance with automatic valve in the flow path, that is not locked, the Surveillance sealed, or otherwise secured in position, is in the Frequency Control correct position. Program (continued) DIABLO CANYON - UNITS 1 & 2 3.5-4 Unit 1 -Amendment No. ~. 200, Rev 10 Page 4 of 8 Unit 2 - Amendment No. ~ . ;w..t,

ECCS - Operating 3.5.2 SURVEILLANCE REQUIREMENTS (continued) SURVEILLANCE FREQUENCY SR 3.5.2.3 Verify ECCS locations susceptible to gas In accordance with accumulation are sufficiently filled with water. the Surveillance Frequency Control Program SR 3.5.2.4 Verify each ECCS pump's developed head at the test In accordance with flow point is greater than or equal to the required the Inservice developed head. Testing Program. SR 3.5.2.5 Verify each ECCS automatic valve in the flow path In accordance with that is not locked, sealed, or otherwise secured in the Surveillance position, actuates to the correct position on an actual Frequency Control or simulated actuation signal. Program SR 3.5.2.6 Verify each ECCS pump starts automatically on an In accordance with actual or simulated actuation signal. the Surveillance Frequency Control Program SR 3.5.2.7 Verify, for each ECCS throttle valve listed below, In accordance with each mechanical position stop is in the correct the Surveillance position. Frequency Control Program Charging Injection Safety Injection Throttle Valves Throttle Valves 8810A 8822A 88108 88228 8810C 8822C 88100 88220 SR 3.5.2.8 Verify, by visual inspection, each ECCS train In accordance with containment recirculation sump suction inlet is not the Surveillance restricted by debris and the suction inlet trash racks Frequency Control and screens show no evidence of structural distress Program or abnormal corrosion. DIABLO CANYON - UNITS 1 & 2 3.5-5 Unit 1 -Amendment No.~'~, Rev 10 Page 5 of 8 Unit 2 - Amendll}ent No. ~, ~,

Containment Spray and Cooling Systems 3.6.6 SURVEILLANCE REQUIREMENTS SURVEILLANCE FREQUENCY SR 3.6.6.1 ---------------------------N0 T E------------------------------ Not required to be met for system vent flow paths opened under administrative control. Verify each containment spray manual, power In accordance with the operated, and automatic valve in the flow path Surveillance Frequency that is not locked, sealed, or otherwise secured in Control Program position is in the correct position. SR 3.6.6.2 Operate each CFCU for~ 15 minutes. In accordance with the Surveillance Frequency Control Program SR 3.6.6.3 Verify component cooling water flow rate to each In accordance with the required CFCU is~ 1650 gpm. Surveillance Frequency Control Program SR 3.6.6.4 Verify containment spray locations susceptible to In accordance with the gas accumulation are sufficiently filled with water. Surveillance Frequency Control Program SR 3.6.6.5 Verify each containment spray pump's developed In accordance with the head at the flow test point is greater than or Inservice Testing equal to the required developed head. Program SR 3.6.6.6 Verify each automatic containment spray valve in In accordance with the the flow path that is not locked, sealed, or Surveillance Frequency otherwise secured in position, actuates to the Control Program correct position on an actual or simulated actuation signal. SR 3.6.6.7 Verify each containment spray pump starts In accordance with the automatically on an actual or simulated actuation Surveillance Frequency signal. Control Program SR 3.6.6.8 Verify each CFCU starts automatically on an In accordance with the actual or simulated actuation signal. Surveillance Frequency . Control Program (continued) DIABLO CANYON - UNITS 1 & 2 3.6-15 Unit 1 -Amendment No. ~. 2-00, Rev 7 Page 15 of 19 Unit 2 -Amendment No. ~ , 2-Q.i,

Containment Spray and Cooling Systems 3.6.6 SURVEILLANCE REQUIREMENTS (continued) SURVEILLANCE FREQUENCY SR 3.6.6.9 Verify each spray nozzle is unobstructed. In accordance with the Surveillance Frequency Control Program SR 3.6.6.10 Verify each CFCU starts on low speed . In accordance with the Surveillance Frequency Control Program DIABLO CANYON - UNITS 1 & 2 3.6-15a Unit 1 -Amendment No. ~. 2-00, Rev 7 Page 16 of 19 Unit 2 -Amendment No. ~. 2-G-4-,

RHR and Coolant Circulation - High Water Level 3.9.5 SURVEILLANCE REQUIREMENTS SURVEILLANCE FREQUENCY SR 3.9.5.1 With the reactor subcritical less than 57 hours, In accordance with the verify one RHR loop is in operation and circulating Surveillance reactor coolant at a flow rate of~ 3000 gpm, Frequency Control OR Program With the reactor subcritical for 57 hours or more, In accordance with the verify one RHR loop is in operation and circulating Surveillance reactor coolant at a flow rate of~ 1300 gpm. Frequency Control Program SR 3.9.5.2 Verify required RHR loop locations susceptible to In accordance with the gas accumulation are sufficiently filled with water. Surveillance Frequency Control Program DIABLO CANYON - UNITS 1 & 2 3.9-5 Unit 1 -Amendment No.~.~. Rev 5 Page 8 of 11 Unit 2 -Amendment No. ~. :2-G-i,

RHR and Coolant C_irculation - Low Water Level 3.9.6 SURVEILLANCE REQUIREMENTS SURVEILLANCE FREQUENCY SR 3.9.6.1 With the reactor subcritical less than 57 hours, In accordance with the verify one RHR loop is in operation and circulating Surveillance reactor coolant at a flow rate of;::: 3000 gpm, Frequency Control Program In accordance with the With the reactor subcritical for 57 hours or more, Surveillance verify one RHR loop is in operation and circulating Frequency Control reactor coolant at a flow rate of;::: 1300 gpm. Program SR 3.9.6.2 Verify correct breaker alignment and indicated In accordance with the power available to the required RHR pump that is Surveillance not in operation. Frequency Control Program SR 3.9.6.3 Verify RHR loop locations susceptible to gas In accordance with the accumulation are sufficiently filled with water. Surveillance Frequency Control Program DIABLO CANYON - UNITS 1 & 2 3.9-7 Unit 1 -Amendment No. 4J.a, 2-00, Rev 5 Page 10 of 11 Unit 2 -Amendment No. 4J.a, 2-G-i,

Enclosure Attachment 3 PG&E Letter DCL-16-001 Technical Specification Bases Changes (For information only)

RCS Loops - MODE 4 B 3.4.6 BASES LCO (continued) temperature difference limits the available relative energy source and the pressurizer level condition provides an expansion volume to accommodate possible reactor coolant thermal swell. These conditions are intended to prevent a low temperature overpressure event due to a thermal transient when a RCP is started. An OPERABLE RCS loop comprises an OPERABLE RCP and an OPERABLE SG, which has the minimum water level specified in SR 3.4.6.2. Similarly for the RHR System, an OPERABLE RHR loop comprises an OPERABLE RHR pump capable of providing forced flow to an OPERABLE RHR heat exchanger. RCPs and RHR pumps are OPERABLE if they are capable of being powered and are able to provide forced flow if required. A RHR loop is in operation when the pump is operating and providing forced flow through the loop. Because a loop can be operating without being OPERABLE, the LCO requires at least one loop OPERABLE and in operation. Management of gas voids is important to RHR System OPERABILITY. APPLICABILITY In MODE 4, this LCO ensures forced circulation of the reactor coolant to remove decay heat from the core and to provide proper boron mixing. One loop of either RCS or RHR provides sufficient circulation for these purposes. However, two loops consisting of any combination of RCS and RHR loops are required to be OPERABLE to meet single failure considerations. Operation in other MODES is covered by: LCO 3.4.4, "RCS Loops - MODES 1 and 2"; LCO 3.4.5, "RCS Loops - MODE 3"; LCO 3.4.7, "RCS Loops- MODE 5, Loops Filled"; LCO 3.4.8, "RCS Loops - MODE 5, Loops Not Filled"; LCO 3.9.5, "Residual Heat Removal (RHR) and Coolant Circulation-High Water Level" (MODE 6); and LCO 3.9.6, "Residual Heat Removal (RHR) and Coolant Circulation-Low Water Level" (MODE 6). ACTIONS A.1 and A.2 If one required RCS loop is inoperable and two RHR loops are inoperable, redundancy for heat removal is lost. Action must be initiated to restore a second RCS loop or RHR loop to OPERABLE status. The immediate Completion Time reflects the importance of maintaining the availability of two paths for heat removal. (continued) DDIABLO CANYON- UNITS 1 & 2 Rev 8A Page 26 of 108 B3.4.x.DOCTab B3!4u3rm~ . DOC 0120.16270919.1043 1.1-1

RCS Loops - MODE 4 B 3.4.6 BASES SURVEILLANCE SR 3.4.6.2 REQUIREMENTS SR 3.4.6.2 requires verification of SG OPERABILITY. SG (continued) OPERABILITY is verified by ensuring that the secondary side narrow range water level is ~ 15%. If the SG secondary side narrow range water level is < 15%, the tubes may become uncovered and the associated loop may not be capable of providing the heat sink necessary for removal of decay heat. The Surveillance Frequency is based on operating experience, equipment reliability, and plant risk and is controlled under the Surveillance Frequency Control Program. SR 3.4.6.3 Verification that the required pump is OPERABLE ensures that an additional RCS or RHR pump can be placed in operation, if needed, to maintain decay heat removal and reactor coolant circulation. Verification is performed by verifying proper breaker alignment and power available to the required pump. The Surveillance Frequency is based on operating experience, equipment reliability, and plant risk and is controlled under the Surveillance Frequency Control Program. SR 3.4 .6.4 _ __ _ _ _______ _ _________ _ _ _ __ __ _ _ _ _____ ___ __ __ - 1~.....F_o_rm _ att _e_d_:_un_d_er_lin_e_ _ _ _ _ __.~ RHR System piping and components have the potential to develop voids and pockets of entrained gases. Preventing and managing gas intrusion and accumulation is necessary for proper operation of the required RHR loop(s) and may also prevent water hammer, pump cavitation, and pumping of noncondensible gas into the reactor vessel. Selection of RHR System locations susceptible to gas accumulation is based on a review of system design information. including piping and instrumentation drawings. isometric drawings. plan and elevation drawings, and calculations. The design review is supplemented by system walk downs to validate the system high points and to confirm the location and orientation of important components that can become sources of gas or could otherwise cause gas to be trapped or difficult to remove during system maintenance or restoration . Susceptible locations depend on plant and system configuration . such as stand-by versus operating conditions . The RHR System is OPERABLE when it is sufficiently filled with water. Acceptance criteria are established for the volume of accumulated gas at susceptible locations. If accumulated gas is discovered that exceeds the acceptance criteria for the susceptible location (or the volume of accumulated gas at one or more susceptible locations exceeds an acceptance criteria for gas volume at the suction or discharge of a pump) the Surveillance is not met. If it is determined by subsequent eva luation that the RHR System is not rendered inoperable by the accumulated gas (i.e. the system is sufficiently filled with water) , the Surveillance may be declared met. Accumulated gas should be DDIABLO CANYON- UNITS 1 & 2 Rev 8A Page 28 of 108 B3.4.x.DOCTab B3 !4t:J3rog .ooc 0120.16270919.1043 1.1-1

RCS Loops - MODE 4 B 3.4.6 Surveillance may be declared met. Accumulated gas should be eliminated or brought within the acceptance criteria limits. RHR System locations susceptible to gas accumulation are monitored and. if gas is found . the gas volume is compared to the acceptance criteria for the location . Susceptible locations in the same system flow path which are subject to the same gas intrusion mechanisms may be verified by monitoring a representative sub-set of susceptible locations. Monitoring may not be practical for locations that are inaccessible due to radiological or environmental conditions . the plant configuration . or personnel safety. For these locations alternative methods (e.g .. operating parameters . remote monitoring) may be used to monitor the susceptible location. Monitoring is not required for susceptible locations where the maximum potential accumulated gas void volume has been evaluated and determined to not challenge system OPERABILITY. The accuracy of the method used for monitoring the susceptible locations and trending of the results should be sufficient to assure system OPERABILITY during the Surveillance interval. This SR is modified by a Note that states the SR is not required to be performed until 12 hours after entering MODE 4. In a rapid shutdown. there may be insufficient time to verify all susceptible locations prior to entering MODE 4. The Surveillance Frequency is controlled under the Surveillance Frequency Control Program . The Surveillance Frequency may vary by location susceptible to gas accumulation .

                                                                                                                    .- --- - - -{ Formatted Table REFERENCES            1. Diablo Canyon Power Plant Pressure and Temperature Limits Report.

2. LAR 16-01 Application to Revise Technical Specifications to Adopt TSTF-523 , "Generic Letter 2008-01 . Managing Gas Accumulation ," Using the Consolidated Line Item Improvement Process.

                                                                                                                                  ,.( Deleted: Tab_83!4u3r08.DOC
                                                                                                                                                                 =====<
                                                                                                                            ',*,*:A Deleted: 0919.1043 DDIABLO CANYON- UNITS 1 & 2                                                                                                

Rev SA Page 29 of 108 ,./ Tab B3!4u3r08. DO C, __________________________ 0121 .064§,__________________________________________________________ / 1.1 -1

RCS Loops - MODE 5, Loops Filled B 3.4.7 BASES LCO The Note specifies that a RCP may be started if the pressurizer water (continued) level is less than 50% . This option of RCP start with pressurizer water level less than 50% supports plant operational flexibility. The open volume in the pressurizer provides space to sustain reactor coolant thermal swell without incurring a possible excessive pressure transient due to energy additions from the S/G secondary water. The purpose of conditions to allow initial RCP start when none is running is to prevent a possible low temperature RCS overpressure event due to a thermal transient when a RCP is started. The condition of SG/RCS temperature difference limits the available relative energy source and the pressurizer level condition provides an expansion volume to accommodate possible reactor coolant thermal swell . These conditions are intended to prevent a low temperature overpressure event due to a thermal transient when a RCP is started. Note 4 provides for an orderly transition from MODE 5 to MODE 4 during a planned heatup by permitting removal of RHR loops from operation when at least one RCS loop is in operation. This Note provides for the transition to MODE 4 where an RCS loop is permitted to be in operation and replaces the RCS circulation function provided by the RHR loops. RHR pumps are OPERABLE if they are capable of being powered and are able to provide flow if required. A SG can perform as a heat sink via natural circulation when it has an adequate water level and is OPERABLE. Management of gas voids is important to RHR System OPERABILITY. APPLICABILITY "Loops filled" is a condition in which natural circulation can be used as a backup means of decay heat removal if forced circulation via RHR is lost. RCS loops are considered filled when the RCS is capable of being pressurized to at least 150 psig, no gas has been directly injected into the RCS, and the RCS has not been drained below 112 ft (Ref. 2). In addition to these requirements, crediting heat removal via natural circulation requires at least two steam generators filled to 2::15% narrow range level and vented, or capable of being vented, to the atmosphere, and auxiliary feedwater available to add water to the relied-upon steam generators (Ref. 1). A loops filled condition is established at the completion of steam generator U-tube vacuum refill or after "bumping" RCPs. In MODE 5 with RCS loops filled, this LCO requires forced circulation of the reactor coolant to remove decay heat from the core and to provide proper boron mixing . One loop of RHR provides sufficient circulation for these purposes. However, one additional RHR loop is required to be OPERABLE, or the secondary side water level of at least two SGs is required to be ;;::: 15%. (continued) DDIABLO CANYON- UNITS 1 & 2 Rev 8A Page 32 of 108 B3.4.x.DOCTab B3!4u3FO!lDOC 0120.16270919.1043 1.1-1

RCS Loops - MODE 5, Loops Filled B 3.4.7 BASES SURVEILLANCE SR 3.4.7.2 REQUIREMENTS Verifying that at least two SGs are OPERABLE by ensuring their (continued) secondary side narrow range water levels are 2: 15% ensures an alternate decay heat removal method via natural circulation in the event that the second RHR loop is not OPERABLE. If both RHR loops are OPERABLE, this Surveillance is not needed . The Surveillance Frequency is based on operating experience, equipment reliability, and plant risk and is controlled under the Surveillance Frequency Control Program. SR 3.4.7.3 Verification that a second RHR pump is OPERABLE ensures that an additional pump can be placed in operation , if needed, to maintain decay heat removal and reactor coolant circulation. Verification is performed by verifying proper breaker alignment and power available to the RHR pump. If secondary side water level is 2: 15% in at least two SGs, this Surveillance is not needed. The Surveillance Frequency is based on operating experience, equipment reliability, and plant risk and is controlled under the Surveillance Frequency Control Program. SR 3.4.7.4 - ---- ---- - - -- - ------------ - - --- ----- ------~

                                                                                                    - Formatted: Underline RHR System piping and components have the potential to develop                    Formatted: Underline voids and pockets of entrained gases. Preventing and managing gas intrusion and accumulation is necessary for proper operation of the required RHR loop(s) and may also prevent water hammer, pump cavitation . and pumping of noncondensible gas into the reactor vessel.

Selection of RHR System locations susceptible to gas accumulation is based on a review of system design information. including piping and instrumentation drawings. isometric drawings, plan and elevation drawings. and calculations . The design review is supplemented by system walk downs to validate the system high points and to confirm the location and orientation of important .components that can become sources of gas or could otherwise cause gas to be trapped or difficult to remove during system maintenance or restoration . Susceptible locations depend on plant and system configuration, such as stand-by versus operating conditions . The RHR System is OPERABLE when it is sufficiently filled with water. Acceptance criteria are established for the volume of accumulated gas at susceptible locations . If accumulated gas is discovered that exceeds the acceptance criteria for the susceptible location (or the volume of accumulated gas at one or more susceptible locations exceeds an acceptance criteria for gas volume at the suction or discharge of a pump) , the Surveillance is not met. If it is determined by subsequent eva luation that the RHR System is not rendered inoperable by the accumulated gas (i.e .. the system is sufficiently filled with water), the DDIABLO CANYON - UNITS 1 & 2 Rev 8A Page 35 of 108 B3.4.x.DOCTab Ba !4t:Jarog.ooc 0120.16270919.104a 1.1-1

RCS Loops - MODE 5, Loops Filled B 3.4.7 accumulated gas (i.e .. the system is sufficiently filled with water). the Surveillance may be declared met. Accumulated gas should be eliminated or brought within the acceptance criteria limits. RHR System locations susceptible to gas accumulation are monitored and . if gas is found. the gas volume is compared to the acceptance criteria for the location . Susceptible locations in the same system flow path which are subject to the same gas intrusion mechanisms may be verified by monitoring a representative sub-set of susceptible locations . Monitoring may not be practical for locations that are inaccessible due to radiological or environmental conditions. the plant configuration . or personnel safety. For these locations alternative methods (e.g .. operating parameters. remote monitoring) may be used to monitor the susceptible location. Monitoring is not required for susceptible locations where the maximum potential accumulated gas void volume has been evaluated and determined to not challenge system OPERABILITY. The accuracy of the method used for monitoring the susceptible locations and trending of the results should be sufficient to assure system OPERABILITY during the Surveillance interval. The Surveillance Frequency is controlled under the Surveillance Frequency Control Program . The Surveillance Frequency may vary by location susceptible to gas accumulation . REFERENCES 1. NRC Information Notice 95-35, "Degraded Ability of Steam Generators to Remove Decay Heat by Natural Circulation ."

2. AR A0582812.

3. LAR 16-01 Application to Revise Technical Specifications to Adopt TSTF-523 . "Generic Letter 2008-01 . Managing Gas Accumulation." Using the Consolidated Line Item Improvement Process.

                                                                                                                  ,{ Deleted: Tab_B3!4u3r08.DOC DDIABLO CANYON- UNITS 1 & 2 Rev SA Page 36 of 108 Tab B3!4u3r08.DO C. ________________________ 0121 .064a nnm * *

• n* n * * * * * * *
• n.Cn_mCnC*mnn**n * * *n //::A Deleted' 0919,1043 1.1-1

RCS Loops - MODE 5, Loops Not Filled B 3.4.8 BASES LCO An OPERABLE RHR loop is comprised of an OPERABLE RHR pump (continued) capable of providing forced flow to an OPERABLE RHR heat exchanger. RHR pumps are OPERABLE if they are capable of being powered and are able to provide flow if required. Management of gas voids is important to RHR System OPERABILITY. APPLICABILITY In MODE 5 with loops not filled, this LCO requires core heat removal and coolant circulation by the RHR System. The "loops filled" condition requires that the RCS is capable of being pressurized to at least 150 psig, no gas has been directly injected into the RCS, and the RCS has not been drained to below 112ft (Ref. 1). Loops filled is based on the ability to credit natural circulation as a backup means of decay heat removal, and until the above conditions are met, the "loops not filled" condition is applicable. Operation in other MODES is covered by: LCO 3.4.4, "RCS Loops- MODES 1 and 2"; LCO 3.4.5, "RCS Loops - MODE 3"; LCO 3.4.6, "RCS Loops - MODE 4"; LCO 3.4.7, "RCS Loops- MODE 5, Loops Filled"; LCO 3.9.5, "Residual Heat Removal (RHR) and Coolant Circulation-High Water Level" (MODE 6); and LCO 3.9.6, "Residual Heat Removal (RHR) and Coolant Circulation-Low Water Level" (MODE 6). Since LCO 3.4.8 contains Required Actions with immediate Completion Times, it is not permitted to enter LCO 3.4.8 from either LCO 3.4.7, "RCS Loops - MODE 5, Loops Filled" or from MODE 6 unless the requirements of LCO 3.4.8 are met. ACTIONS A.1 If only one RHR loop is OPERABLE and in operation , redundancy for RHR is lost. Action must be initiated to restore a second loop to OPERABLE status. The immediate Completion Time reflects the importance of maintaining the availability of two paths for heat removal. (continued) DDIABLO CANYON- UNITS 1 & 2 Rev 8A Page 38 of 108 B3.4.x.DOCTal3 B3!4~::~3r08 . DOC 0120.16270919.104 d 1.1-1

RCS Loops - MODE 5, Loops Not Filled B 3.4.8 BASES ACTIONS B.1 and B.2 (continued) If no required RHR loops are OPERABLE or in operation, except during conditions permitted by Note 1, all operations involving introduction of coolant into the RCS with boron concentration less than required to meet the minimum SDM of LCO 3.1.1 must be suspended and action must be initiated immediately to restore an RHR loop to OPERABLE status and operation. Boron dilution requires forced circulation from at least one RHR pump for proper mixing so that inadvertent criticality can be prevented. Suspending the introduction of coolant into the RCS with boron concentration less than required to meet the minimum SDM of LCO 3.1.1 is required to assure continued safe operation. With coolant added without forced circulation, unmixed coolant could be introduced to the core, however coolant added with boron concentration meeting the minimum SDM maintains acceptable margin to subcritical operations. The immediate Completion Time reflects the importance of maintaining operation for heat removal. The action to restore must continue until one loop is restored to OPERABLE status and operation. SURVEILLANCE SR 3.4.8.1 REQUIREMENTS This SR requires verification that one loop is in operation. Verification may include flow rate, temperature, or pump status monitoring, which help ensure that forced flow is providing heat removal. The Surveillance Frequency is based on operating experience, equipment reliability, and plant risk and is controlled under the Surveillance

• Frequency Control Program.

SR 3.4.8.2 Verification that the required number of pumps are OPERABLE ensures that additional pumps can be placed in operation, if needed, to maintain decay heat removal and reactor coolant circulation. Verification is performed by verifying proper breaker alignment and power available to the required pumps. The Surveillance Frequency is based on operating experience, equipment reliability, and plant risk and is controlled under the Surveillance Frequency Control Program. SR 3.4 .8.3 - - ---------- - -------- - ----- ---- ------- - -- - - - - -i..._F_o_rm _a_tt _e_d_: u _ n_d_er_lin_e_ _ _ _ _ ______, RHR System piping and components have the potential to develop voids and pockets of entrained gases . Preventing and managing gas intrusion and accumulation is necessary for proper operation of the RHR loops and may also prevent water hammer. pump cavitation . and pumping of noncondensible gas into the reactor vessel. Selection of RHR System locations susceptible to gas accumulation is based on a review of system design information . including piping and instrumentation drawings. isometric drawings . plan and elevation drawings and calculations . The design review is supplemented by system walk downs to validate the system high po ints and to confirm DDIABLO CANYON- UNITS 1 & 2 Rev 8A Page 39 of 108 B3.4.x.DOCTab B3!4u3rmlDOC 0120.16270919.1043 1.1-1

RCS Loops- MODE 5, Loops Not Filled B 3.4.8 system walk downs to validate the system high points and to confirm the location and orientation of important components that can become_ sources of gas or could otherwise cause gas to be trapped or difficult to remove during system maintenance or restoration. Susceptible locations depend on plant and system configuration, such as stand-by versus operating conditions . The RHR System is OPERABLE when it is sufficiently filled with water. Acceptance criteria are established for the volume of accumulated gas at susceptible locations. If accumulated gas is discovered that exceeds the acceptance criteria for the susceptible location (or the volume of accumulated gas at one or more susceptible locations exceeds an acceptance criteria for gas volume at the suction or discharge of a pump), the Surveillance is not met. If it is determined by subsequent evaluation that the RHR System is not rendered inoperable by the accumulated gas (i.e., the system is sufficiently filled with water) , the Surveillance may be declared met. Accumulated gas should be eliminated or brought within the acceptance criteria limits. RHR System locations susceptible to gas accumulation are monitored and, if gas is found , the gas volume is compared to the acceptance criteria for the location . Susceptible locations in the same system flow path which are subject to the same gas intrusion mechanisms may be verified by monitoring a representative sub-set of susceptible locations. Monitoring may not be practical for locations that are inaccessible due to radiological or environmental conditions , the plant configuration, or personnel safety. For these locations alternative methods (e.g ., operating parameters , remote monitoring) may be used to monitor the susceptible location . Monitoring is not required for susceptible locations where the maximum potential accumulated gas void volume has been evaluated and determ ined to not challenge system OPERABILITY. The accuracy of the method used for monitoring the susceptible locations and trend ing of the results should be sufficient to assure system OPERABILITY during the Surveillance interval. The Surveillance Frequency is controlled under the Surveillance Frequency Control Program . The Surveillance Frequency may vary by location susceptible to gas accumulation. REFERENCES 1. AR A0582812. 2 . LAR 16-01 Application to Revise Technical Specifications to Adopt TSTF-523 , "Generic Letter 2008-01, Managing Gas Accumulation ," Using the Consolidated Line Item Improvement Process.

                                                                                                     ,{ Deleted: Tab_B3!4u3rDB.DOC DDIABLO CANYON- UNITS 1 & 2 Rev SA Page 40 of 108 Tab B3f4u3r08. DO C. __________________________ 0121 .064a 1.1-1

ECCS - Operating B 3.5.2 BASES (continued) LCO In MODES 1, 2, and 3, two independent (and redundant) ECCS trains are required to ensure that sufficient ECCS flow is available, assuming a single failure affecting either train. Additionally, individual components within the ECCS trains may be called upon to mitigate the consequences of other transients and accidents. In MODES 1, 2, and 3, an ECCS train consists of a centrifugal charging subsystem, an Sl subsystem, and an RHR subsystem . Each train includes the piping, instruments, and controls to ensure an OPERABLE flow path capable of taking suction from the RWST upon an Sl signal. During an event requiring ECCS actuation, a flow path is required to provide an abundant supply of water from the RWST to the RCS via the ECCS pumps and their respective supply headers to each of the four cold legs. The ECCS suction is manually transferred to the containment recirculation sump to place the system in the recirculation mode of operation to supply its flow to the RCS hot and cold legs. During the recirculation operation, the RHR pumps provide suction to the charging and Sl pumps. Management of gas voids is important to ECCS OPERABILITY. The containment recirculation sump is considered OPERABLE when all the following conditions are met:

• All strainer disks are bolted in or blanks are installed .
• No structural distress that could impair strainer/trash rack function .
• Covers to all 13 access ports to the strainer system are installed.
• The two expansion joints connecting the rear strainer plenums to the pipe structure are intact.
• Lower plenum drain valve (SI-1-294 for Unit 1 or Sl-2-295 for Unit 2) is closed, or the pipe cap or inlet strainer (STR-440) is installed .

During recirculation operation, the flow path for each train must maintain its designed independence to ensure that no single failure can disable both ECCS trains. (continued) DIABLO CANYON -UNITS 1 & 2 Rev SA Page 13 of 39 Tab_B3!5u3r08.DOC 0120.16300919.1002 1.1-1

ECCS - Operating B 3.5.2 BASES SURVEILLANCE SR 3.5.2.2 (continued) REQUIREMENTS The Surveillance Frequency is based on operating experience, equipment reliability, and plant risk and is controlled under the Surveillance Frequency Control Program . The Surveillance is modified by a Note which exempts system vent flow paths opened under administrative control. The administrative control should be proceduralized and include stationing a dedicated individual at the system vent flow path who is in continuous communication with the operators in the control room . This individual will have a method to rapidly close the system vent flow path if directed. SR 3.5.2.3 ECCS piping and components have the VVith the exception of the operating GGP, the EGGS pumps are normally in a standby, nonoperating mode. As such , flow path piping has the potential to develop voids and pockets of entrained gases. Preventing and managing gas intrusion and accumulation is necessary for -proper operation of the ECCS and may also Maintaining the piping from the EGGS pumps to the RGS full of 'Nater ensures that the system 'Nil I perform properly, injecting its full capacity into the RGS upon demand. This will also prevent water hammer, pump cavitation, gas binding, and pumping of non-condensable gas (e.g. , air, nitrogen , or hydrogen) into the reactor vessel following an Sl signal or during shutdown oooling . Selection of ECCS locations susceptible to gas accumulation is based on a review of system design information, including piping and instrumentation drawings, isometric drawings. plan and elevation drawings . and calculations. The design review is supplemented by system walk downs to validate the system high points and to confirm the location and orientation of important components that can become sources of gas or could otherwise cause gas to be trapped or difficult to remove during system maintenance or restoration . Susceptible locations depend on plant and system configuration . such as stand-by versus operating conditions. The ECCS is OPERABLE when it is sufficiently filled with water. Acceptance criteria are established for the volume of accumulated gas at susceptible locations. If accumulated gas is discovered that exceeds the acceptance criteria for the susceptible location (or the volume of accumulated gas at one or more susceptible locations exceeds an acceptance criteria for gas volume at the suction or discharge of a pump) the Surveillance is not met. If it is determined by subsequent evaluation that the ECCS is not rendered inoperable by the accumulated gas (i.e .. the system is sufficiently filled with water), the Surveillance may be declared met. Accumulated gas should be eliminated or brought within the acceptance criteria limits. DIABLO CANYON- UNITS 1 & 2 Rev 8A Page 19 of 39 Tab_B3!5u3r08. DOC 0120.16300919.1002 1.1-1

ECCS - Operating B 3.5.2 ECCS locations susceptible to gas accumulation are monitored and . if gas is found. the gas volume is compared to the acceptance criteria for the location . Susceptible locations in the same system flow path which are subject to the same gas intrusion mechanisms may be verified by monitoring a representative sub-set of susceptible locations. Monitoring may not be practical for locations that are inaccessible due to radiological or environmental cond itions . the plant configuration . or personnel safety. For these locations alternative methods (e.g ., operating parameters. remote monitoring) may be used to monitor the susceptible location. Monitoring is not required for susceptible locations where the maximum potential accumulated gas void volume has been evaluated and determined to not challenge system OPERABILITY. The accuracy of the method used for monitoring the susceptible locations and trending of the results should be sufficient to assure system OPERABILITY during the Surveillance interval. The Surveillance Frequency is based on operating experience, equipment reliability, and plant risk and is controlled under the Surveillance Frequency Control Program. The Surveillance Frequency may vary by location susceptible to gas accumulation. The intent of the SR is to assure the ECCS piping is adequately vented. Different means of verification, as alternates to venting the accessible system high points, can be employed to provide this assurance, such as ultrasonic testing the vent lines of the ECCS pump casings and accessible high point vents. SR 3.5.2.4 Periodic surveillance testing of ECCS pumps to detect gross degradation caused by impeller structural damage or other hydraulic component problems is required by the ASME Code. (Ref. 8) This type of testing may be accomplished by measuring the pump developed head at only one point of the pump characteristic curve. This verifies both that the measured performance is within an acceptable tolerance of the original pump baseline performance and that the performance at the test flow is within the performance assumed in the plant safety analysis. SRs are specified in the applicable portions of the lnservice Testing Program, which encompasses Subsection ISTB of the ASME Code for Operation and Maintenance of Nuclear Power Plants. (Ref. 8). This section of the ASME Code provides the activities and frequencies necessary to satisfy the requirements. The following ECCS pumps are required to develop the indicated differential pressure when tested on recirculation flow: CCP ~ 2400 psid Sl pump~ 1455 psid RHR pump~ 165 psid (continued) DIABLO CANYON- UNITS 1 & 2 Rev SA Page 20 of 39 Tab_B3!5u3r08. DOC 0120.16300919.1002 1.1-1

ECCS - Operating B 3.5.2 BASES REFERENCES 1. 10 CFR 50, Appendix A, GDC 35.

2. 10 CFR 50.46.

3. FSAR, Sections 6.3 and 7.3.

4. FSAR, Chapter 15, "Accident Analysis ."

5. NRC Memorandum to V. Stello, Jr., from R.L. Baer, "Recommended Interim Revisions to LCOs for ECCS Components," December 1, 1975.

6. IE Information Notice No. 87-01.

7. BTP EICSB-18, Application of the Single Failure Criteria to Manually-Controlled Electrically-Operated Valves.

8. ASME Code for Operation and Maintenance of Nuclear Power Plants, 2001 Edition including 2002 and 2003 Addenda .

9. Design Changes DCP C-49857 (Unit 1), DCP C-50857 (Unit 2).

j_Q,_License Amendment 202/203, December 31, 2008. 11 . LAR 16-01 Application to Revise Technical Specifications to Adopt TSTF-523. "Generic Letter 2008-01 . Managing Gas Accumulation, " Using the Consolidated Line Item Improvement Process.

                                                                                                                          ) Deleted: 0919.1002 DIABLO CANYON - UNITS 1 & 2                                                                                             

Rev SA Page 22 of 39 / Tab_B3 !5u3r08. DOC 0121 .065E; _______________________________________________________________________________ ___ / 1.1-1

ECCS - Shutdown B 3.5.3 BASES (continued) LCO In MODE 4, one of the two independent (and redundant) ECCS trains (as defined for MODE 4) is required to be OPERABLE to ensure that sufficient ECCS flow is available to the core following a DBA. In MODE 4, an ECCS train consists of a centrifugal charging subsystem and an RHR subsystem. Each train includes the piping, instruments, and controls to ensure an OPERABLE flow path capable of taking suction from the RWST and transferring suction to the containment recirculation sump. The containment recirculation sump is considered OPERABLE when all the following conditions are met:

• All strainer disks are bolted in or blanks are installed.
• No structural distress that could impair strainer/trash rack function.
• Covers to all 13 access ports to the strainer system are installed.
• The two expansion joints connecting the rear strainer plenums to the pipe structure are intact.
• Lower plenum drain valve (SI-1-294 for Unit 1 or Sl-2-295 for Unit 2) is closed, or the pipe cap or inlet strainer (STR-440) is installed.

During an event requiring ECCS actuation, a flow path is required to provide an abundant supply of water from the RWST to the RCS via the ECCS charging and RHR pumps and their respective supply headers to each of the four cold legs. In the long term , this flow path may be switched to take its supply from the containment recirculation sump and to deliver its flow to the RCS hot and cold legs. Management of gas voids is important to ECCS OPERABILITY. This LCO is modified by a Note that allows an RHR train to be considered OPERABLE during system alignment and operation for decay heat removal, if capable of being manually realigned (remote or local) to the ECCS mode of operation and not otherwise inoperable. This allows operation in the RHR mode during MODE 4. (continued) DIABLO CANYON- UNITS 1 & 2 Rev 8A Page 24 of 39 Tab_B3!5u3r08.DOC 0120.16300919.1002 1.1-1

ECCS - Shutdown B 3.5.3 BASES ACTIONS A.1 (continued) With both RHR pumps and heat exchangers inoperable, it would be unwise to require the plant to go to MODE 5, where the only available heat removal system is the RHR. Therefore, the appropriate action is to initiate measures to restore one ECCS RHR subsystem and to continue the actions until the subsystem is restored to OPERABLE status. Opening the containment recirculation sump strainer system access ports, or lower plenum drain valve (SI-1-294 for Unit 1 or Sl-2-295 for Unit 2) without pipe cap or inlet strainer (STR-440) installed, in MODE 4 is considered to be a condition which is outside the accident analysis. Therefore, LCO 3.0.3 must be immediately entered. lU. With no ECCS centrifugal charging subsystem OPERABLE, due to the inoperability of the centrifugal charging pump or flow path from the RWST, the plant is not prepared to provide high pressure response to Design Basis Events requiring Sl. The 1 hour Completion Time to restore at least one ECCS centrifugal charging subsystem to OPERABLE status ensures that prompt action is taken to provide the required cooling capacity or to initiate actions to place the plant in MODE 5, where an ECCS train is not required .

                       .Q.,1 When the Required Actions of Condition B cannot be completed within the required Completion Time, a controlled shutdown should be initiated. Twenty-four hours is a reasonable time, based on operating experience, to reach MODE 5 in an orderly manner and without challenging plant systems or operators.

SURVEILLANCE SR 3.5.3.1 REQUIREMENTS The applicable Surveillance descriptions from Bases 3.5.2 apply. REFERENCES 1. Abnormal Response Guideline, ARG- 2, Rev. 0, Feb. 28, 1992. Note: The applicable references from BASES 3.5.2 apply.

2. LAR 16-01 Application to Revise Technical Specifications to Adopt TSTF-523. "Generic Letter 2008-01 . Managing Gas Accumulation. " Using the Consolidated Line Item Improvement Process.

DIABLO CANYON- UNITS 1 & 2 Rev 8A Page 26 of 39

• I Tab_B3!5u3r08.DOC 012 1.0656.

1.1-1

Containment Spray and Cooling Systems B 3.6.6 BASES APPLICABLE sequenced loading of equipment, containment spray pump startup, and SAFETY spray line filling (Ref. 4). The CFCUs performance for post accident ANALYSES conditions is given in Reference 4. The result of the analysis is that (continued) each train (two CFCUs) combined with one train of containment spray can provide 100% of the required peak cooling capacity during the post accident condition. The modeled Containment Cooling System actuation from the containment analysis is based upon a response time associated with exceeding the containment High-High pressure setpoint to achieving full Containment Cooling System air and safety grade cooling water flow. The Containment Cooling System total response time includes signal delay, DG startup (for loss of offsite power), and component cooling water pump startup times. The Containment Spray System and the Containment Cooling System satisfies Criterion 3 of 10CFR50.36(c)(2)(ii). LCO During a DBA LOCA, a minimum of two CFCUs and one containment spray train are required to maintain the containment peak pressure and temperature below the design limits (Refs. 4). Additionally, one containment spray train is also required to remove iodine from the containment atmosphere and maintain concentrations below those assumed in the safety analysis. To ensure that these requirements are met, two containment spray trains and the CFCU system consisting of four CFCUs or three CFCUs each supplied by a different vital bus must be OPERABLE. Therefore, in the event of an accident, at least one train of containment spray and two CFCUs operate, assuming the worst case single active failure occurs. Each Containment Spray train typically includes a spray pump, spray headers, nozzles, valves, piping, instruments, and controls to ensure an OPERABLE flow path capable of taking suction from the RWST upon an ESF actuation signal. Upon actuation of the RWST Low-Low alarm, the containment spray pumps are secured . Containment spray could then be supplied as required by an RHR pump taking suction from the containment sump. Management of gas voids is important to Containment Spray System OPERABILITY. Each CFCU includes cooling coils, dampers, fans, instruments, and controls to ensure an OPERABLE flow path. APPLICABILITY In MODES 1, 2, 3, and 4, a DBA could cause a release of radioactive material to containment and an increase in containment pressure and temperature requiring the operation of the containment spray trains and CFCUs. In MODES 5 and 6, the probability and consequences of these events are reduced due to the pressure and temperature limitations of these MODES. Thus, the Containment Spray System and the Containment Cooling System are not required to be OPERABLE in MODES 5 and 6.

                                                                                                                                  ,.{ Deleted: Tab_B3!6u3r08.DOC (continued)        ,'*,:,:'..{ Deleted: 1007.1502 DIABLO CANYON -UNITS 1 & 2                                                                                                           ...___ _ _ _ _ _ _ _ _       _..J Rev 8C Page 38 of 53                                                                                                     :?

1~9?_1§. _____________________________________________________________________ ~- ----------/ Tab B3!6u3r08. DO C, ___ Q1_?_ 1.1-1

Containment Spray and Cooling Systems B 3.6.6 BASES (continued) SURVEILLANCE SR 3.6.6.1 REQUIREMENTS Verifying the correct alignment for manual, power operated, and automatic valves in the containment spray flow path provides assurance that the proper flow paths will exist for Containment Spray System operation. The containment spray flow path consists of the direct flow path from the fluid source (e.g., RWST) to the supplied safety-related component (e.g., spray headers) and portions of any branch line flow path off the direct flow path that a valve misposition could result in degradation of the system safety function. This SR does not apply to valves that are locked, sealed, or otherwise secured in position, since these were verified to be in the correct position prior to locking, sealing, or securing. This SR also does not apply to valves which are closed and secured by a cap or blind flange (e.g., manual test, vent, and drain valves), to valves that cannot be inadvertently misaligned (e.g., check valves), or to valves in instrument or sample lines. This SR does not require any testing or valve manipulation . Rather, it involves verification, through a system walkdown, which may include the use of local or remove indicators, that those valves outside containment (only check valves are inside containment) and capable of potentially being mispositioned are in the correct position . The Surveillance Frequency is based on operating experience, equipment reliability, and plant risk and is controlled under the Surveillance Frequency Control Program. The Surveillance is modified by a Note which exempts system vent flow paths opened under administrative control. The administrative control should be proceduralized and include stationing a dedicated individual at the system vent flow path who is in continuous communication with the operators in the control room . This individual will have a method to rapidly close the system vent flow path if directed. SR 3.6.6.2 Operating each required CFCU for;:::: 15 minutes ensures that all trains are OPERABLE and that all associated controls are functioning properly. It also ensures that blockage, fan or motor failure, or excessive vibration can be detected for corrective action . The Surveillance Frequency is based on operating experience, equipment reliability, and plant risk and is controlled under the Surveillance Frequency Control Program. SR 3.6.6.3 Verifying that each required CFCU is receiving the required component cooling water flow of;:::: 1650 gpm provides assurance that the design flow rate assumed in the safety analyses will be achieved (Ref. 4). The component cooling water (CCW) system is hydraulically balanced during normal operation to ensure that at least 1650 gpm is delivered to * ,{ Deleted: Tab_B3!6u3ros.ooc each CFCU during a design bases event (DBA). The hydraulic system ,':::',',':A Deleted: 1oo7.1soz DIABLO CANYON -UNITS 1 & 2 '--------------------> Rev 8C 'Page 42 of 53 _ , Tab B3!6u3r08.DOC. ___ Q1_2_1 ~9X~~ --------------------------------------------------------------------------------- /* 1.1-1

Containment Spray and Cooling Systems B 3.6.6 BASES SURVEILLANCE SR 3.6.6.3 (continued) REQUIREMENTS Operation of the CFCUs is permitted with lower CCW flow to the CFCUs during ASME Section XI testing or decay heat removal in MODE 4 with the residual heat removal heat exchangers in service. To support this conclusion, a calculation was performed to evaluate containment heat removal with one train of containment spray OPERABLE and reduced CCW flow to three CFCUs. The calculation concluded that this configuration would provide adequate heat removal to ensure that the maximum design pressure of containment was not exceeded during a DBA in MODE 1. This analysis also determined that a single failure could not be tolerated during this condition and still assure that the maximum design pressure of containment would not be exceeded. (Ref. 6) The Surveillance Frequency is based on operating experience, equipment reliability, and plant risk and is controlled under the Surveillance Frequency Control Program. __ .-- { Formatted: No underline

                       ,S_f3__ ~&~ *_4 Containment Spray System piping and components have the potential to develop voids and pockets of entrained gases. Preventing and managing gas intrusion and accumulation is necessary for proper operation of the containment spray trains and may also prevent water hammer and pump cavitation .

Selection of Containment Spray System locations susceptible to gas accumulation is based on a review of system design information, including piping and instrumentation drawings, isometric drawings. plan and elevation drawings, and calculations . The design review is supplemented by system walk downs to validate the system high points and to confirm the location and orientation of important components that can become sources of gas or could otherwise cause gas to be trapped or difficult to remove during system maintenance or restoration . Susceptible locations depend on plant and system configuration . such as stand-by versus operating conditions . The Containment Spray System is OPERABLE when it is sufficiently filled with water. Acceptance criteria are established for the volume of accumulated gas at susceptible locations. If accumulated gas is discovered that exceeds the acceptance criteria for the susceptible location (or the volume of accumulated gas at one or more susceptible locations exceeds an acceptance criteria fo r gas volume at the suction or discharge of a pump) . the Surveillance is not met. If it is determined by subsequent evaluation that the Containment Spray System is not rendered inoperable by the accumulated gas (i.e .. the system is ,.{ Deleted: Tab_B3!6u3roa.ooc sufficiently filled with water) . the Surveillance may be declared met. ,,:',.,';::',*,' ) Deleted: 1oo7.1soz DIABLO CANYON - UNITS 1 & 2 Rev 8C Page 44 of 53 I Tab B3!6u3r08. DOC., 0121 . 07~!i -----------------------------------------------------------------------~-------J 1.1-1

Containment Spray and Cooling Systems B 3.6.6 Accumulated gas should be eliminated or brought within the acceptance criteria limits . Containment Spray System locations susceptible to gas accumulation are monitored and. if gas is found . the gas volume is compared to the acceptance criteria for the location . Susceptible locations in the same system flow path which are subject to the same gas intrusion mechanisms may be verified by monitoring a representative sub-set of susceptible locations. Monitoring may not be practical for locations that are inaccessible due to radiological or environmental conditions. the plant configuration. or personnel safety. For these locations alternative methods (e.g., operating parameters. remote monitoring) may be used to monitor the susceptible location. Monitoring is not required for susceptible locations where the maximum potential accumulated gas void volume has been evaluated and determined to not challenge system OPERABILITY. The accuracy of the method used for monitoring the susceptible locations and trending of the results should be sufficient to assure system OPERABILITY during the Surveillance interval. The Surveillance Frequency is controlled under the Surveillance Frequency Control Program. The Surveillance Frequency may varv by location susceptible to gas accumulation.

.1= --_ _ _ _ _ _ _ ____.~

SR 3.6.6.,f2_____________________________________________________________________________________ .- ---{.__D_e_le_te_d-' Verifying each containment spray pump's developed head at the flow test point is greater than or equal to the required developed head (205 psid) ensures that spray pump performance has not degraded during the cycle. Flow and differential pressure are normal tests of centrifugal pump performance required by the ASME O&M Code (Ref. 5). Since the containment spray pumps cannot be tested with flow through the spray headers, they are tested on recirculation flow. During refueling operation, a containment spray pump can be aligned to take suction from the refueling water storage tank (RWST) and discharge into the residual heat removal system discharge line back to the RWST. Flow using this lineup can achieve full design flow of 2600 gpm. This test confirms one point on the pump design curve and is indicative of overall performance. Such inservice tests confirm component OPERABILITY, trend performance, and detect incipient failures by abnormal performance. The Frequency of the SR is in accordance with the lnservice Testing Program. SR 3.6.6,§_and_~R- ~*~L? .Z ____________________________________________________________ ~---- - - {>=D=e=le=te=d:,;,.§=========<

                                                                                                                         ------{ Deleted:.§ These SRs require verification that each automatic containment spray valve actuates to its correct position and that each containment spray pump starts upon receipt of an actual or simulated actuation of a containment high-high pressure signal with a coincident "S" signal.                                        ,( Deleted: Tab_B3!6u3r08.DOC
              ... .. . . This Surveillance is not required for valves that are locked, sealed, or
                                                                                                                              ',',*:A Deleted: 1007.1502 DIABLO CANYON- UNITS 1 & 2                                                                                                   

Rev 8C Page 45 of 53  :/ Tab B3!6u3r08.DO<; Q}_?1_ ~074_§. ___________________________ __ ______________________________________________ ___ ___ / 1.1 -1

Containment Spray and Cooling Systems B 3.6.6 BASES SURVEILLANCE SR 3.6.6,§___________________________________________________________________________________ ___ - -- {'---o_e_le_te_d----':= z -------------' REQUIREMENTS This SR requires verification that each CFCU actuates upon receipt of (continued) an actual or simulated safety injection signal. The Surveillance Frequency is based on operating experience, equipment reliability, and plant risk and is controlled under the Surveillance Frequency Control Program. SR 3.6.6..@ ___________________________________________________________________ ----1 Deleted: .§

                                                                                                                                                           ~-----------~

With the containment spray inlet valves closed and the spray header drained of any solution, low pressure air or smoke can be blown through test connections. This SR ensures that each spray nozzle is unobstructed and provides assurance that spray coverage of the containment during an accident is not degraded. The Surveillance Frequency is based on operating experience, equipment reliability, and plant risk and is controlled under the Surveillance Frequency Control Program. SR 3.6.6 10 _/-- { Deleted:~

                     .=..:....:c........=....:..=;..:...=.~
                                                          'f ~- ------------------------------------------------------------------------------- - -        "-------------~

The CFCUs are designed to start or restart in low speed upon receipt of an Sl signal. This SR ensures that this feature is functioning properly. The Surveillance Frequency is based on operating experience, equipment reliabil ity, and plant risk and is controlled under the Surveillance Frequency Control Program. REFERENCES 1. FSAR, Appendix 3.1A

2. 10 CFR 50, Appendix K.

3. FSAR, Section 6.2.1.

4. FSAR, Section 6.2.2.

5. ASME Code for Operation and Maintenance of Nuclear Power Plants, 2001 Edition including 2002 and 2003 Addenda.

6. License Amendment 89/88, April 16, 1996.

7. Calculation STA-075, "Minimum ECCS Flow and Minimum Recirculation Spray Flow During the Sump Recirculation Phases."

8. License Amendment 202/203, December 31, 2008.

9. LAR 16-01 Application to Revise Technical Specifications to Adopt TSTF-523, "Generic Letter 2008-01, Managing Gas Accumulation ,"

Using the Consolidated Line Item Improvement Process. e , *. ***

                                                                                                                                                         ,{ Deleted: Tab_83!6u3rOB.DOC
                                                                                                                                                  , / ;)    Deleted* 1007.1502 DIABLO CANYON- UNITS 1 & 2 Rev 8C Page 47 of 53 Tab B3!6u3r08.Doc; ___ _Q121 ._ 9X1~                              -------------------------------------- ________________________________________ ./

1.1-1

RHR arid Coolant Circulation - High Water Level B 3.9.5 BASES LCO b. Mixing of borated coolant to minimize the possibility of criticality; (continued) and

c. Indication of reactor coolant temperature.

An OPERABLE RHR loop includes an RHR pump, a heat exchanger, valves, piping, instruments, and controls to ensure an OPERABLE flow path and to determine the low end temperature. The flow path starts in one of the RCS hot legs and is returned to the RCS cold legs. Management of gas voids is important to RHR System OPERABILITY. The LCO is modified by a Note that allows the required operating RHR loop to be removed from service for up to 1 hour per 8 hour period, provided no operations are permitted that would dilute the RCS boron concentration with coolant at boron concentrations less than required to meet the minimum boron concentration of LCO 3.9.1. Boron concentration reduction with coolant at boron concentrations less than required to assure the minimum required RCS boron concentration is maintained is prohibited because uniform concentration distribution cannot be ensured without forced circulation. This permits operations such as valve testing, core mapping, or alterations in the vicinity of the reactor vessel hot leg nozzles. During this 1 hour period, decay heat is removed by natural convection to the large mass of water in the refueling cavity. The LCO is also modified by a second Note that allows the required RHR Loop to be removed from service for up to 2 hours per 8 hour period to support surveillance leak rate testing of the RCS to RHR suction isolation valves, provided that no operations are permitted which might result in reduction of boron concentration. During this 2 hour period, decay heat is removed by natural convection to the large mass of water in the refueling cavity and the RCS . APPLICABILITY One RHR loop must be OPERABLE and in operation in MODE 6, with the water level 2 23 ft above the top of the reactor vessel flange, to provide decay heat removal. The 23 ft water level was selected because it corresponds to the 23 ft requirement established for fuel movement in LCO 3.9.7, "Refueling Cavity Water Level." Requirements for the RHR System in other MODES are covered by LCOs in Section 3.4, Reactor Coolant System (RCS), and Section 3.5, Emergency Core Cooling Systems (ECCS). RHR loop requirements in MODE 6 with the water level< 23ft are located in LCO 3.9.6, "Residual Heat Removal (RHR) and Coolant Circulation-Low Water Level." (continued)

                                                                                                                              ,{ Deleted: Tab_B3!9u3r08.DOC
                                                                                                                           /,{ Deleted: 0206.0612 DIABLO CANYON - UNITS 1 & 2                                                                                           ,,,',.;/

Rev SA Page 18 of 28 Tab B3!9u3r08. DO G. 0121 .0754. _________________________________________________________________________ ________ / 1.1-1

RHR and Coolant Circulation- High Water Level B 3.9.5 BASES (continued) SURVEILLANCE SR 3.9.5.1 REQUIREMENTS This Surveillance demonstrates that the RHR loop is in operation and circulating reactor coolant. The flow rate of 3000 gpm is determ ined by the flow rate necessary to provide sufficient decay heat removal capability and to prevent thermal and boron stratification in the core prior to 57 hours of core subcriticality. The second part of this Surveillance serves the same function but with 57 hours or more of core subcriticality. The flow rate of 1300 gpm is determined by the flow rate necessary to provide sufficient decay heat removal capability and to prevent thermal and boron stratification in the core. Both of these flow rates are points of the same flow rate verses decay heat. The Surveillance Frequency is based on operating experience, equipment reliability, and plant risk and is controlled under the Surveillance Frequency Control Program . SR 3.9.5.2 RHR System piping and components have the potential to develop voids and pockets of entrained gases. Preventing and managing gas intrusion and accumulation is necessary for proper operation of the RHR loops and may also prevent water hammer. pump cavitation. and pumping of noncondensible gas into the reactor vessel. Selection of RHR System locations susceptible to gas accumulation is based on a review of system design information . including piping and instrumentation drawings. isometric drawings. plan and elevation drawings . and calculations. The design review is supplemented by system walk downs to validate the system high points and to confirm the location and orientation of important components that can become sources of gas or could otherwise cause gas to be trapped or difficult to remove during system maintenance or restoration . Susceptible locations depend on plant and system configuration , such as stand-by versus operating conditions . The RHR System is OPERABLE when it is sufficiently filled with water. Acceptance criteria are established for the volume of accumulated gas at susceptible locations. If accumulated gas is discovered that exceeds the acceptance criteria for the susceptible location (or the volume of accumulated gas at one or more susceptible locations exceeds an acceptance criteria for gas volume at the suction or discharge of a pump). the Surveillance is not met. If it is determined by subsequent evaluation that the RHR System is not rendered inoperable by the accumulated gas (i.e .. the system is sufficiently filled with water) . the Surveillance may be declared met. Accumulated gas should be eliminated or brought within the acceptance criteria limits.

                                                                                                                                   ,{ Deleted: Tab_B3!9u3r08.DOC RHR System locations susceptible to gas accumulation are monitored                                          ,{
                                                                                                                              ',','>  Deleted: 0206 .0612 DIABLO CANYON- UNITS 1 & 2                                                                                                  

Rev 8A Page 20 of 28  :/ Tab B3!9u3r08. DO C. ___ 0121 .0754_ _______________________________________________________________________ __________ _/ 1.1-1

RHR and Coolant Circulation - High Water Level B 3.9.5 and, if gas is found , the gas volume is compared to the acceptance criteria for the location . Susceptible locations in the same system flow path which are subject to the same gas intrusion mechanisms may be verified by monitoring a representative sub-set of susceptible locations. Monitoring may not be practical for locations that are inaccessible due to radiological or environmental conditions. the plant configuration. or personnel safety. For these locations alternative methods (e.g., operating parameters . remote monitoring) may be used to monitor the susceptible location . Monitoring is not required for susceptible locations where the maximum potential accumulated gas void volume has been evaluated and determined to not challenge system OPERABILITY. The accuracy of the method used for monitoring the susceptible locations and trending of the results should be sufficient to assure system OPERABILITY during the Surveillance interval. The Surveil lance Frequency is controlled under the Surveillance Frequency Control Program . The Surveillance Frequency may vary by location susceptible to gas accumulation . REFERENCES 1. FSAR Section 5.5.7. I

2. License Amendment 28/27 January 5 1988.

1 1

                                                                                                                         +------ -{ Formatted Table

3. LAR 16-01 Application to Revise Technical Specifications to Adopt TSTF-523 "Generic Letter 2008-01 Managing Gas I Accumulation ," Using the Consolidated Line Item Improvement Process.

l Deleted: Tab_B3!9u3r08.DOC

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RHR and Coolant Circulation- Low Water Level B 3.9.6 BASES LCD An OPERABLE RHR loop consists of an RHR pump, a heat (continued) exchanger, valves, piping, instruments and controls to ensure an OPERABLE flow path and to determine the low end temperature. The flow path starts in one of the RCS hot legs and is returned to the RCS cold legs. Management of gas voids is important to RHR System OPERABILITY. An operable RHR loop must be capable of being realigned to provide an operable flow path. APPLICABILITY Two RHR loops are required to be OPERABLE, and one RHR loop must be in operation in MODE 6, with the water level< 23ft above the top of the reactor vessel flange , to provide decay heat removal. Requirements for the RHR System in other MODES are covered by LCOs in Section 3.4, Reactor Coolant System (RCS), and Section 3.5, Emergency Core Cooling Systems (ECCS). RHR loop requirements in MODE 6 with the water level;:: 23ft are located in LCO 3.9.5, "Residual Heat Removal (RHR) and Coolant Circulation-High Water Level." ACTIONS A.1 and A.2 If less than the required number of RHR loops are OPERABLE, action shall be immediately initiated and continued until the RHR loop is restored to OPERABLE status and to operation or until;:: 23ft of water level is established above the reactor vessel flange. When the water level is ;:: 23 ft above the reactor vessel flange, the Applicability changes to that of LCO 3.9.5, and only one RHR loop is required to be OPERABLE and in operation . An immediate Completion Time is necessary for an operator to initiate corrective actions. liJ. If no RHR loop is in operation, there will be no forced circulation to provide mixing to establish uniform boron concentrations. Suspending positive reactivity additions that could result in failure to meet the minimum boron concentration limit is required to assure continued safe operation . Introduction of coolant inventory must be from sources that have a boron concentration greater than that required in the RCS for minimum refueling boron concentration. This may result in an overall reduction in RCS boron concentration, but provides acceptable margin to maintaining subcritical operation . B.2 If no RHR loop is in operation, actions shall be initiated immediately, and continued , to restore one RHR loop to operation. Since the unit is in Conditions A and B concurrently, the restoration of two OPERABLE RHR loops and one operating RHR loop should be accomplished expeditiously. (continued)

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RHR and Coolant Circulation- Low Water Level B 3.9.6 BASES ACTIONS B.3 (continued) If no RHR loop is in operation, all containment penetrations providing direct access from the containment atmosphere to the outside atmosphere must be closed within 4 hours. With the RHR loop requirements not met, the potential exists for the coolant to boil and release radioactive gas to the containment atmosphere. Closing containment penetrations that are open to the outside atmosphere ensures that dose limits are not exceeded. The Completion Time of 4 hours is reasonable at water levels above reduced inventory, based on the low probability of the coolant boiling in that time. At reduced inventory conditions or mid-loop operations, additional actions are taken to provide containment closure in a reduced period of time (Ref. 3). Reduced inventory is defined as less than Elev. 111 ft. SURVEILLANCE SR 3.9.6.1 REQUIREMENTS This Surveillance demonstrates that one RHR loop is in operation and circulating reactor coolant. The flow rate of more than 3000 gpm is determined by the flow rate necessary to provide sufficient decay heat removal capability and to prevent thermal and boron stratification in the core prior to 57 hours subcritical. The second part of this Surveillance serves the same function but with 57 hours or more of core subcriticality and provides a reduced flow rate of 1300 gpm based upon a reduced decay heat load. Both of these flow rates are points of the same flow rate verses decay heat curves. The 1300 gpm limit also precludes exceeding the 1675 gpm upper flow limit to prevent vortexing and air entrainment of the RHR piping system. RHR pump vortexing (failure to meet pump suction requirements) during mid-loop operation may result in RHR pump failure and non-conservative RCS level indication. The Surveillance Frequency is based on operating experience, equipment reliability, and plant risk and is controlled under the Surveillance Frequency Control Program . SR 3.9.6.2 Verification that the required pump is OPERABLE ensures that an additional RHR pump can be placed in operation, if needed, to maintain decay heat removal and reactor coolant circulation. Verification is performed by verifying proper breaker alignment and power available to the required pump. The Surveillance Frequency is based on operating experience, equipment reliability, and plant risk and is controlled under the Surveillance Frequency Control Program. SR 3.9.6.3 RHR System piping and components have the potential to develop voids and pockets of entrained gases. Preventing and managing gas intrusion and accumulation is necessary for proper operation of the RHR loops and may also prevent water hammer. pump cavitation . and - ADeleted: Tab_B 3!9 3r0B.DOC U DIABLO CANYON- UNITS 1 & 2 /::'A'-o_e_le_te_d_: o_2_o6_.o_61_2_ _ _ __ ____, Rev SA Page 24 of 28  :? Tab B3!9u3r08.DOC. ___ _Q~_~_t9751 ___________________________________________________________*_____________________ / 1.1 -1

RHR and Coolant Circulation- Low Water Level B 3.9.6 pumping of noncondensible gas into the reactor vessel. Selection of RHR System locations susceptible to gas accumulation is based on a review of system design information. including piping and instrumentation drawings. isometric drawings. plan and elevation drawings. and calculations. The design review is supplemented by system walk downs to validate the system high points and to confirm the location and orientation of important components that can become sources of gas or could otherwise cause gas to be trapped or difficult to remove during system maintenance or restoration. Susceptible locations depend on plant and system configuration. such as stand-by versus operating conditions . The RHR System is OPERABLE when it is sufficiently filled with water. Acceptance criteria are established for the volume of accumulated gas at susceptible locations. If accumulated gas is discovered that exceeds the acceptance criteria for the susceptible location (or the volume of accumulated gas at one or more susceptible locations exceeds an acceptance criteria for gas volume at the suction or discharge of a pump), the Surveillance is not met. If it is determined by subsequent evaluation that the RHR System is not rendered inoperable by the accumulated gas (i.e .. the system is sufficiently filled with water). the Surveillance may be declared met. Accumulated gas should be eliminated or brought within the acceptance criteria limits. RHR System locations susceptible to gas accumulation are monitored and . if gas is found . the gas volume is compared to the acceptance criteria for the location . Susceptible locations in the same system flow path which are subject to the same gas intrusion mechanisms may be verified by monitoring a representative sub-set of susceptible locations. Monitoring may not be practical for locations that are inaccessible due to radiological or environmental conditions. the plant configuration. or personnel safety. For these locations alternative methods (e.g .. operating parameters. remote monitoring) may be used to monitor the susceptible location . Monitoring is not required for susceptible locations where the maximum potential accumulated gas void volume has been evaluated and determined to not challenge system OPERABILITY. The accuracy of the method used for monitoring the susceptible locations and trending of the results should be sufficient to assure system OPERABILITY during the Surveillance interval. The Surveillance Frequency is controlled under the Surveillance Frequency Control Program . The Surveillance Frequency may vary by location susceptible to gas accumulation. (continued)

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RHR and Coolant Circulation - Low Water Level B 3.9.6 BASES (continued) REFERENCES 1. FSAR, Section 5.5.7

2. License Amendment 28/27, January 5, 1988.

3. Generic Letter 88-17, "Loss of Decay Heat Removal. "

4. LAR 16-01 Appl ication to Revise Technical Specifications to Adopt TSTF-523, "Generic Letter 2008-01, Managing Gas Accumulation, " Using the Consolidated Line Item Improvement Process.

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