DCL-15-135, Response to NRC Request for Additional Information Regarding License Amendment Request 15-03, Application of Alternative Source Term.

Response to NRC Request for Additional Information Regarding License Amendment Request 15-03, Application of Alternative Source Term.

ML15310A522
Person / Time
Site:	Diablo Canyon
Issue date:	11/06/2015
From:	Allen B Pacific Gas & Electric Co
To:	Document Control Desk, Office of Nuclear Reactor Regulation
References
DCL-15-135
Download: ML15310A522 (7)

Text

Pacific Gas and Electric Company Barry S. Allen Diablo Canyon Power Plant Vice President, Nuclear Services Mail Code 104/6 P. 0. Box 56 Avila Beach, CA 93424 November 6, 2015 805.545.4888 Internal: 6 91.4888 Fax: 805.545.6445 PG&E Letter DCL-15-135 U.S. Nuclear Regulatory Commission 10 CFR 50.90 ATTN: Document Control Desk Washington, DC 20555-0001 Docket No. 50-275, OL-DPR-80

• Docket No. 50-323, OL-DPR-82 Diablo Canyon Units 1 and 2 Response to NRC Request for Additional Information Regarding License Amendment Request 15-03. "Application of Alternative Source Term"

References:

1. PG&E Letter DCL-15-069, License Amendment Request 15-03, "Application of Alternative Source Term," dated June 17, 2015 (ADAMS Accession No. ML15176A539)

2. PG&E Letter DCL-15-105, Supplement to License Amendment Request 15-03, "Application of Alternative Source Term," dated August 31, 2015 (ADAMS Accession No. ML15243A363)

3. E-mail from NRC Project Manager Siva P. Lingam, "Diablo Canyon 1 and 2- Requests for Additional Information for License Amendment Request 15-03 to Adopt the Alternative Source Term per 10 CFR 50.67 (TAG Nos. MF6399 and MF6400)," dated October 7, 2015

Dear Commissioners and Staff:

Pacific Gas and Electric (PG&E) Letter DCL-15-069, "License Amendment Request 15-03, 'Application of Alternative Source Term,"' (Reference 1), dated June 17, 2015, and supplemented by PG&E Letter DCL-15-105, "Supplement to License Amendment Request 15-03, 'Application of Alternative Source Term,"'

(Reference 2), dated August 31, 2015, submitted License Amendment Request (LAR) 15-03, "Application of Alternative Source Term."

On October 7, 2015, the NRC Electrical Engineering Branch (EEEB) requested additional information (Reference 3) required to complete the review of LAR 15-03.

PG&E's responses to the EEEB's staff's questions are provided in the Enclosure.

This information does not affect the results of the technical evaluation or the no significant hazards consideration determination previously transmitted in References 1 and 2.

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-15-135 November 6, 2015 Page2 A regulatory commitment is included, as identified in Attachment 1 of the Enclosure.

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 November 6, 2015.

Sincerely,

/J~-=5. M-Barry s fAuen Vice President, Nuclear Services MJRM/4557/50705089-12 Enclosure cc: Diablo Distribution cc/enc: Marc L. Dapas, NRC Region IV Administrator

.Thomas R. Hipschman, NRC Senior Resident Inspector Siva P. Lingam, NRR Project Manager Gonzalo L. Perez, Branch Chief, California Dept 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-15-135 EEEB Response

Enclosure PG&E Letter DC L-15-135 PG&E Response to NRC Request for Additional Information Regarding License Amendment Request 15-03, "Application of Alternative Source Term" NRC EEEB-RAI-1 Address whether any nonsafety-related systems and components are credited in the accident source term analyses. If so,:

Describe the independence (electrical and physical separation) of these systems from the safety-related systems. Provide a detailed discussion on why a fault on the non-Class 1E electrical circuit will not propagate to the Class 1E electrical circuit.

PG&E Response

i. As described in Sections 2.2 and 5.2 of Attachment 4 of the license amendment request (LAR), to maintain the integrity of the safety-related (Pacific Gas and Electric Company (PG&E) Design Class I) plant vent discharge pathway, the 40-inch GE/GW containment penetration area ventilation line and the 2-inch gaseous radwaste system line (originally designed as PG&E Design Class I but currently classified as non-safety-related (PG&E Design Class II)), which connect to the plant vent, will be upgraded as follows:

a. The portion of the 2-inch gaseous radwaste system line that connects to the plant vent will be upgraded to safety-related (PG&E Design Class 1).

b. The portion of the GE/GW 40-inch containment penetration area ventilation line that connects to the plant vent up to and including the isolating damper solenoid valves, the associated damper actuators, and the pressure switches will be upgraded to safety-related (PG&E Design Class 1).

Based on the above upgrades to PG&E Design Class I, there will be no credit taken for non-safety-related (PG&E Design Class II) electrical or instrumentation components because the independence (electrical and physical separation) of the upgrades will be in accordance with PG&E Design Class I.

ii. Safety-related (PG&E Design Class I) systems and components are credited in the alternative source term (AST) analyses except as described in Section 7 .2.3.1 of Attachment 4 of the LAR. Credit is taken for pressure boundary integrity of the containment pressure/vacuum relief system ductwork, which, though classified as non-safety-related (PG&E Design Class II), is seismically qualified. Thus, environmental releases from the containment pressure/vacuum relief system ductwork are assumed to occur via the safety-related (PG&E Design Class I) plant vent. The credit taken for the PG&E Design Class II containment pressure/vacuum relief system ductwork is for pressure boundary integrity only and does not credit any electrical or instrumentation components.

2

Enclosure PG&E Letter DCL-15-135 NRC EEEB-RAI-2 On page 7 of the LAR, the licensee stated that for the containment spray system no changes in operation are being proposed, other than requiring its operation within 12 minutes following terminating injection spray, instead of being optional in accordance with emergency operating procedures or at the discretion of the Technical Support Center. Does this change in operation require a change to the emergency diesel generators (EDGs) loading sequence?

PG&E Response The change in operation of the containment spray system does not impact the EDG loading sequence. When the containment spray system is operating in the "injection" phase, the motive force is provided by the containment spray pumps. The injection mode of operation is unchanged by the AST LAR. The AST LAR credits containment spray operation in the "recirculation" phase. Motive force is provided by a residual heat removal (RHR) pump. The RHR pumps are manually restarted in the recirculation

• phase. The RHR recirculation flow will be shared between containment spray and core cooling. Both RHR pumps are assumed to be in operation in the 4 kV bus loading calculation 015-DC prior to implementation of AST.

NRC EEEB-RAI-3 Is there a change of equipment qualification (EQ) profile? If so, provide a list and description of components being added to your Title 10 of the Code of Federal Regulations (10 CFR), Part 50, Section 50.49 program due to this LAR. Confirm that these components are qualified for the environmental conditions they are expected to be exposed to. Also, please confirm that the source terms used for EQ of safety-related equipment, and the shielding and vital area access dose rates will continue to be based on assumptions in Technical Information Document [TID]-14844, "Calculation of Distance Factors for Power and Test Reactor Sites."

PG&E Response EQ Containment Pressure and Temperature Profile:

The Diablo Canyon Power Plant (DCPP) Units 1 and 2 containment integrity analysis performed by Westinghouse in support of implementation of AST at DCPP determined that there has been no impact on the EQ envelope post-LOCA peak pressure and temperature inside containment. The containment analysis also concluded that the use of containment spray in the recirculation mode for the minimum safeguards case (i.e.,

recirculation spray initiated 12 minutes after termination of injection spray and continuing on to about 6.25 hours2.893519e-4 days <br />0.00694 hours <br />4.133598e-5 weeks <br />9.5125e-6 months <br /> following a loss of coolant accident (LOCA)) has a minimal effect on the current long term pressure and temperature envelopes used for equipment qualification.

3

Enclosure PG&E Letter DCL-15-135 PG&E is making the following regulatory commitment:

Existing environmentally qualified components will be evaluated per the EQ program to confirm acceptability as part of AST implementation. As required, the list of the components associated with 50.49 program will be updated after completing the evaluation per the EQ program, as part of the AST implementation.

Radiation Source Terms used for EQ of safety-related equipment, and the shielding and vital area access dose rates As stated in Section 2.0 of Attachment 4 of AST LAR 15-03 which provides the technical assessment supporting the application, and Attachment 8 of LAR 15-03 which provides the proposed update of Sections 3.11 and 12.1.1 of the Updated Final Safety Analysis Report, the post-LOCA integrated doses utilized for radiological environmental qualification of PG&E Design Class I equipment, and the estimated operator mission doses while performing vital functions post-LOCA, will continue to be based on assumptions in TID-14844, and will remain unaffected by this application.

4

Enclosure Attachment 1 PG&E Letter DCL-15-135 Regulatory Commitment PG&E is making the following regulatory commitment:

Existing environmentally qualified components will be evaluated per the EQ program to confirm acceptability as part of AST implementation. As required, the list of the components associated with 50.49 program will be updated after completing the evaluation per the EQ program, as part of the AST implementation.

Pacific Gas and Electric Company Barry S. Allen Diablo Canyon Power Plant Vice President, Nuclear Services Mail Code 104/6 P. 0. Box 56 Avila Beach, CA 93424 November 6, 2015 805.545.4888 Internal: 6 91.4888 Fax: 805.545.6445 PG&E Letter DCL-15-135 U.S. Nuclear Regulatory Commission 10 CFR 50.90 ATTN: Document Control Desk Washington, DC 20555-0001 Docket No. 50-275, OL-DPR-80

• Docket No. 50-323, OL-DPR-82 Diablo Canyon Units 1 and 2 Response to NRC Request for Additional Information Regarding License Amendment Request 15-03. "Application of Alternative Source Term"

References:

1. PG&E Letter DCL-15-069, License Amendment Request 15-03, "Application of Alternative Source Term," dated June 17, 2015 (ADAMS Accession No. ML15176A539)

2. PG&E Letter DCL-15-105, Supplement to License Amendment Request 15-03, "Application of Alternative Source Term," dated August 31, 2015 (ADAMS Accession No. ML15243A363)

3. E-mail from NRC Project Manager Siva P. Lingam, "Diablo Canyon 1 and 2- Requests for Additional Information for License Amendment Request 15-03 to Adopt the Alternative Source Term per 10 CFR 50.67 (TAG Nos. MF6399 and MF6400)," dated October 7, 2015

Dear Commissioners and Staff:

Pacific Gas and Electric (PG&E) Letter DCL-15-069, "License Amendment Request 15-03, 'Application of Alternative Source Term,"' (Reference 1), dated June 17, 2015, and supplemented by PG&E Letter DCL-15-105, "Supplement to License Amendment Request 15-03, 'Application of Alternative Source Term,"'

(Reference 2), dated August 31, 2015, submitted License Amendment Request (LAR) 15-03, "Application of Alternative Source Term."

On October 7, 2015, the NRC Electrical Engineering Branch (EEEB) requested additional information (Reference 3) required to complete the review of LAR 15-03.

PG&E's responses to the EEEB's staff's questions are provided in the Enclosure.

This information does not affect the results of the technical evaluation or the no significant hazards consideration determination previously transmitted in References 1 and 2.

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-15-135 November 6, 2015 Page2 A regulatory commitment is included, as identified in Attachment 1 of the Enclosure.

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 November 6, 2015.

Sincerely,

/J~-=5. M-Barry s fAuen Vice President, Nuclear Services MJRM/4557/50705089-12 Enclosure cc: Diablo Distribution cc/enc: Marc L. Dapas, NRC Region IV Administrator

.Thomas R. Hipschman, NRC Senior Resident Inspector Siva P. Lingam, NRR Project Manager Gonzalo L. Perez, Branch Chief, California Dept 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-15-135 EEEB Response

Enclosure PG&E Letter DC L-15-135 PG&E Response to NRC Request for Additional Information Regarding License Amendment Request 15-03, "Application of Alternative Source Term" NRC EEEB-RAI-1 Address whether any nonsafety-related systems and components are credited in the accident source term analyses. If so,:

Describe the independence (electrical and physical separation) of these systems from the safety-related systems. Provide a detailed discussion on why a fault on the non-Class 1E electrical circuit will not propagate to the Class 1E electrical circuit.

PG&E Response

i. As described in Sections 2.2 and 5.2 of Attachment 4 of the license amendment request (LAR), to maintain the integrity of the safety-related (Pacific Gas and Electric Company (PG&E) Design Class I) plant vent discharge pathway, the 40-inch GE/GW containment penetration area ventilation line and the 2-inch gaseous radwaste system line (originally designed as PG&E Design Class I but currently classified as non-safety-related (PG&E Design Class II)), which connect to the plant vent, will be upgraded as follows:

a. The portion of the 2-inch gaseous radwaste system line that connects to the plant vent will be upgraded to safety-related (PG&E Design Class 1).

b. The portion of the GE/GW 40-inch containment penetration area ventilation line that connects to the plant vent up to and including the isolating damper solenoid valves, the associated damper actuators, and the pressure switches will be upgraded to safety-related (PG&E Design Class 1).

Based on the above upgrades to PG&E Design Class I, there will be no credit taken for non-safety-related (PG&E Design Class II) electrical or instrumentation components because the independence (electrical and physical separation) of the upgrades will be in accordance with PG&E Design Class I.

ii. Safety-related (PG&E Design Class I) systems and components are credited in the alternative source term (AST) analyses except as described in Section 7 .2.3.1 of Attachment 4 of the LAR. Credit is taken for pressure boundary integrity of the containment pressure/vacuum relief system ductwork, which, though classified as non-safety-related (PG&E Design Class II), is seismically qualified. Thus, environmental releases from the containment pressure/vacuum relief system ductwork are assumed to occur via the safety-related (PG&E Design Class I) plant vent. The credit taken for the PG&E Design Class II containment pressure/vacuum relief system ductwork is for pressure boundary integrity only and does not credit any electrical or instrumentation components.

2

Enclosure PG&E Letter DCL-15-135 NRC EEEB-RAI-2 On page 7 of the LAR, the licensee stated that for the containment spray system no changes in operation are being proposed, other than requiring its operation within 12 minutes following terminating injection spray, instead of being optional in accordance with emergency operating procedures or at the discretion of the Technical Support Center. Does this change in operation require a change to the emergency diesel generators (EDGs) loading sequence?

PG&E Response The change in operation of the containment spray system does not impact the EDG loading sequence. When the containment spray system is operating in the "injection" phase, the motive force is provided by the containment spray pumps. The injection mode of operation is unchanged by the AST LAR. The AST LAR credits containment spray operation in the "recirculation" phase. Motive force is provided by a residual heat removal (RHR) pump. The RHR pumps are manually restarted in the recirculation

• phase. The RHR recirculation flow will be shared between containment spray and core cooling. Both RHR pumps are assumed to be in operation in the 4 kV bus loading calculation 015-DC prior to implementation of AST.

NRC EEEB-RAI-3 Is there a change of equipment qualification (EQ) profile? If so, provide a list and description of components being added to your Title 10 of the Code of Federal Regulations (10 CFR), Part 50, Section 50.49 program due to this LAR. Confirm that these components are qualified for the environmental conditions they are expected to be exposed to. Also, please confirm that the source terms used for EQ of safety-related equipment, and the shielding and vital area access dose rates will continue to be based on assumptions in Technical Information Document [TID]-14844, "Calculation of Distance Factors for Power and Test Reactor Sites."

PG&E Response EQ Containment Pressure and Temperature Profile:

The Diablo Canyon Power Plant (DCPP) Units 1 and 2 containment integrity analysis performed by Westinghouse in support of implementation of AST at DCPP determined that there has been no impact on the EQ envelope post-LOCA peak pressure and temperature inside containment. The containment analysis also concluded that the use of containment spray in the recirculation mode for the minimum safeguards case (i.e.,

recirculation spray initiated 12 minutes after termination of injection spray and continuing on to about 6.25 hours2.893519e-4 days <br />0.00694 hours <br />4.133598e-5 weeks <br />9.5125e-6 months <br /> following a loss of coolant accident (LOCA)) has a minimal effect on the current long term pressure and temperature envelopes used for equipment qualification.

3

Enclosure PG&E Letter DCL-15-135 PG&E is making the following regulatory commitment:

Existing environmentally qualified components will be evaluated per the EQ program to confirm acceptability as part of AST implementation. As required, the list of the components associated with 50.49 program will be updated after completing the evaluation per the EQ program, as part of the AST implementation.

Radiation Source Terms used for EQ of safety-related equipment, and the shielding and vital area access dose rates As stated in Section 2.0 of Attachment 4 of AST LAR 15-03 which provides the technical assessment supporting the application, and Attachment 8 of LAR 15-03 which provides the proposed update of Sections 3.11 and 12.1.1 of the Updated Final Safety Analysis Report, the post-LOCA integrated doses utilized for radiological environmental qualification of PG&E Design Class I equipment, and the estimated operator mission doses while performing vital functions post-LOCA, will continue to be based on assumptions in TID-14844, and will remain unaffected by this application.

4

Enclosure Attachment 1 PG&E Letter DCL-15-135 Regulatory Commitment PG&E is making the following regulatory commitment:

Existing environmentally qualified components will be evaluated per the EQ program to confirm acceptability as part of AST implementation. As required, the list of the components associated with 50.49 program will be updated after completing the evaluation per the EQ program, as part of the AST implementation.