DCL-16-061, Supplement to License Amendment Request 15-03, Application of Alternative Source Term.

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Supplement to License Amendment Request 15-03, Application of Alternative Source Term.
ML16169A264
Person / Time
Site: Diablo Canyon  Pacific Gas & Electric icon.png
Issue date: 06/09/2016
From: Baldwin T
Pacific Gas & Electric Co
To:
Document Control Desk, Office of Nuclear Reactor Regulation
Shared Package
ML16169A267 List:
References
DCL-16-061
Download: ML16169A264 (18)
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Text

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Pacific Gas and Bectric Company"'

Thomas R. Baldwin Diablo Canyon Power Plant Director P.O. Box66 Nuclear Site Services] Avila Beach, CA 93424 805.645.6060 Internal: 691.6060 Fax: 805.545.4234 June 9, 2016 PG&E Letter DCL-16-061 10 CFR 50.90 U.S. Nuclear Regulatory Commission ATTN: Document Control Desk Washington, D.C. 20555-0001 Diablo Canyon Units 1 and 2 Docket No. 50~275, OL-DPR-80 Docket No. 50-323, OL-DPR-82 Supplement to License Amendment Request 15-03. "Application of Alternative Source Term" Referenqes: 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 Acce~sion No. ML15243A363)
3. PG&E Letter DCL-15-152, "Respon_se to NRG Request for Additional Information Regarding License Amendment Request 15-03, 'Application of Alternative Source Term,"' dated December 17, 2015 (ADAMS Accession No. ML16004A356)
4. PG&E Letter DCL-16-044, "Response to NRG Request for Additional Information Regarding License Amendment Request 15-03, 'Application of Alternative Source Term,"' dated April 21, 2016 (ADAMS Accession No. ML16120A027)

Dear Commissioners and Staff:

License Amendment Request (LAR) 15-03, "Application of Alternative Source Term" was submitted by Pacific Gas and Electric (PG&E) Letter DCL-15-069 (Reference 1) and supplemented by PG&E Letter DCL-15-105 (Reference 2). The LAR requested a 'change to the Diablo Canyon Power Plant (DCPP) Units 1 and 2 licensing bases to adopt the alternative source term used in the radiological consequences analysis in accordance with the requirements of 10 CFR 50.67.

A member of the STARS (Strategic Teaming and Resource Sharing)

  • Alliance Callaway
  • Diablo Canyon
  • Palo Verde*
  • Wolf Creek

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Document Control Desk PG&E Letter DCL-16-061 June 9, 2016 Page2 LAR 15-03 stated that a portion of the 2-i,nch gaseous radwaste system line which currently connects to the plant vent will be reclassified as PG&E Design Class I.

The line is currently classified as PG&E Design Class II.

This letter supplements LAR 15-03 by removing one of the proposed license conditions to reclassify the portion of the 2-inch gaseous radwaste system line that connects to the plant vent, as PG&E Design Class I. Classifying the piping as PG&E Design Class I would not have resulted in any physical changes to the piping. It would have, however, resulted in additional administrative burden and increased inspections associated with PG&E Design Class I piping, hangers, and testing, which would increase personnel dose and be an additional burden to plant maintenance, engineering, and inservice inspection personnel.

In consideration of the above, PG&E has evaluated the impacts of not reclassifying (leaving as PG&E Design Class II) the portion of the 2-inch gaseous radwaste system line that connects to the plant*vent. Based on a PG&E assessment, it is concluded there is no need to upgrade the design classification of the 2-inch gaseous radwaste system line that connects to the plant vent to PG&E Design Class I, since:

  • The estimated dose at the exclusion area boundary (EAB) and low population zone (LPZ) is not impacted by a potential break in the 2-inch gaseous radwaste system line (and the associated back flow from the plant vent),

since the atmospheric dispersion factors developed for the EAB and LPZ encompass all post-accident environmental release locations including that associated with the ref~renced break.

  • The dose impact in the control room of a potential break location at the interface of the 2-inch gaseous radwaste system line with the plant vent is bounded by the current dose consequence analyses since the r./O values developed for the plant vent are either conservative or representative of a break at the interface point.
  • The cumulative dose impact in the control room due to back flow from the plant v~nt out of a potential break in (a) the 2-inch gaseous radwaste system line, and (b) in the GSC/SJAE 16-inch exhaust header (or any other PG&E Design Class II piping connected to it), at a location other than the point of interface with the plant vent, is insignificant.

Section 2.4 of LAR 15-03 (Reference 1) has been updated to delete the .

reclassification of the 2-inch gaseous radwaste system line as PG&E Design Class I.

. Section 2.2 of the Technical Report has been updated to delete the reclassification of the 2-inch gaseous radwaste system line as PG&E Design Class I. Section 5.2 of the Technical Report has also been updated to include a discussion of the 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-16-061 June 9, 2016 Page3 cumulative dose impact in the control room as a result of a worst case break in the PG&E Design Class II 2-inch gaseous radwaste system line.

In addition, the applicable pages of the Updated Final Safety Analysis Report (UFSAR) markup, the supplement to LAR 15-03 (Reference 2), and the proposed markup of Appendix D of the license conditions for the Unit 1 and Unit 2 Operating Licenses have been revised.

The attachments to the Enclosure to this letter update the following attachments previously submitted in References 1, 2, 3, and 4: *

  • Attachment 1 - Replacement Markup Pages for License Amendment Request 15-03, Application of Alternative Source Term. This attachment replaces pages 14, 15, and 27 through 29 submitted in the original LAR 15-03 (Reference 1).
  • Attachment 2 - Diablo Canyon Power Plant Technical Report Prepared by WECTEC Global Project Services Inc. (WECTEC) - Implementation of Alternative Source Terms, Summary of Dose Analyses and Results, Revision 3. This attachment replaces Revision 2 of the Technical Report, submitted in Reference 4. Revision 3 of the Technical Report removes the discussion of the reclassification of the 2-inch gaseous radwaste system line connecting to the plant vent. Changes are marked with revision bars.

attachment replaces markup page 2.3-34 of the UFSAR submitted in Reference 3.

  • Attachment 4 - Replacement Markup Page for Supplement to License Amendment Request 15-03, "Application of Alternative Source Term," dated August 31, 2015. This attachment replaces page 2 of the cover letter of the LAR 15-03 Supplement letter (Reference 2).
  • Attachment 5 - e Updated Insert #1-for the License Conditions in Appendix D of the the Unit 1 and Unit 2 Operating Licenses. This attachment replaces the proposed Insert #1 of the markup for the license conditions in Appendix D of -

the Unit 1 and Unit 2 Operating Licenses, previously submitted in Attachment 1 of Reference 2.

The revised pages of LAR 15-03 provided in Attachment 1 supersede those previously submitted in Reference 1.

The revised Technical Report provided in Attachment2 supersedes those previously submitted in Reference 1, Reference 3, and Reference 4.

The revised UFSAR page provided in Attachment 3 supersedes the page previously contained in Reference 3.

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-16-061 June 9, 2016 Page4 This information does not affect the results of the technical evaluation, or the no significant hazards consideration determination, previously submitted in Reference 1.

In accordance with site administrative procedures and the Quality Assurance Program, the proposed amendment has been reviewed by the Plant Staff Review Committee*.

Pursuant to 10 CFR 50.91, PG&E is sending a copy of this proposed amendment to the California Department of Public Health.

PG&E makes no new or revised regulatory commitments (as defined by NEI 99-04) in this letter.

If you have any questions or require additional information, please contact Mr.

Hossain Hamzehee at 805-545-4720.

I have been delegated the authority of James M. Welsch, Vice President - Nuclear Generation, during his absence. I declare under penalty of perjury that the foregoing is true and correct.

  • Executed on June 9, 2016.

Thomas R. Baldwin Director, Nuclear Site Services mjrm/4557150705089 Enclosure cc: Diablo Distribution cc/enc: Marc L. Dapas, NRC Region IV Gonzalo L. Perez, Branch Chief, California Dept of Public Health John P. Reynoso, NRC Acting Senior Resident Inspector Balwant K. Singal, NRR Senior Project Manager A member of the STARS (Strategic Teaming and Resource Sharing) Alliance

  • Callaway
  • Diablo Canyon
  • Palo Verde
  • Wolf Creek r

Enclosure PG&E Letter DCL-16-061 Evaluation This letter supplements License Amendment Request (LAR) 15-03 by removing one of the proposed license conditions to reclassify the portion of the 2-inch gaseous radwaste system line that connects to the plant vent, as PG&E Design Class I.

Classifying the piping as PG&E Design Class I would not have resulted in any physical changes to the piping. It would have, however, resulted in additional administrative burden and increased inspections associated with PG&E Design Class I piping, hangers, and testing, which would increase personnel dose and be an additional burden to plant maintenance, engineering, and inservice inspection personnel.

In consideration of the above, PG&E has evaluated the impacts of not reclassifying (leaving as PG&E Design Class II) the portion of the 2-inch gaseous radwaste system line that connects to the plant vent. Based on a PG&E assessment, it is concluded there is no need to upgrade the design classification of the 2-inch gaseous radwaste system line that connects to the plant vent to PG&E Design Class I, since:

  • The estimated dose* at the exclusion area boundary (EAB) and low population zone (LPZ) is not impacted by a potential break in the 2-inch gaseous radwaste system line (and the associated back flow from the plant vent),

since the atmospheric dispersion factors developed for the EAB and LPZ encompass all post-accident environmental release locations including that associated with the referenced break.

.

  • The dose impact in the control room of a potential break location at the interface of the 2-inch gaseous radwaste system line with the plant vent is bounded by the current dose consequence analyses since the xlQ values developed for the plant vent are either conservative or representative of a break at the interface point.
  • The cumulative dose impact in the control room due to back flow from the plant vent out of a potential break in (a) the 2-inch gaseous radwaste system line, and (b) in the GSC/SJAE 16-inch exhaust header (or any other PG&E Design Class II piping connected to it), at a location other than the point of interface with the plant vent, is insignificant.

The following attachments to the Enclosure to this letter replace pages previously .

submitted in References 1, 2, 3, and 4:

  • Attachment 1 - Replacement Markup Pages for License Amendment Request 15-03, Application of Alternative SourceTerm. This attachment replaces pages 14, 15, and 27 through 29 submitted in the original LAR 15-03 (Reference 1)
  • Attachment 2- Diablo Canyon Power Plant Technical Report Prepared by WECTEC Global Project Services Inc. (WECTEC) - Implementation of Alternative Source Terms, Summary of Dose Analyses and ResuJts, 1

Enclosure PG&E Letter DCL-16-061 Revision 3. This attachment replaces Revision 2.ofthe Technical Report, submitted in Reference 4. Revision 3 of the Technical Report removes the discussion of the reclassification of the 2-inch gaseous radwaste system line connecting to the plant vent. Changes are marked with revision bars.

  • Attachment 4 - Replacement Markup Page for Supplement to License Amendment Request 15-03, "Application of Alternative Source Term," dated August 31, 2015. This attachment replaces page 2 of the cover letter of the LAR 15-03 Supplement letter (Reference 2).
  • Attachment 5 - Updated Insert #1 for the License Conditions in Appendix D of the Unit 1 and Unit 2 Operating Licenses. This attachment replaces the proposed Insert #1 of the markup for the license conditions in Appendix D of the Unit 1 and Unit 2 Operating Licenses, previously submitted in Attachment 1 of Reference 2.

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. PG&E Letter DCL-15-152, Response to NRC Request for Additional Information Regarding License Amendment Reqµest 15-03, "Application of Alternative Source Term," dated December 17, 2015 (ADAMS Accession No. ML16004A356)
4. PG&E Letter DCL-16-044, Response to NRC Request for Additional Information Regarding License Amendment Request 15-03, "Application of Alternative Source Term," dated April 21, 2016 (ADAMS Accession No. ML 16120A~27) 2

Enclosure Attachment 1 PG&E Letter DCL-16-061 ATTACHMENT 1 Replacement Markup Pages for License Amendment Request 15-03 Application of Alternative Source Term

Enclosure Attachment 1 PG&E Letter DCL-16-061 Enclosure PG&E Letter DCL-15-069 consequences to the public at the EAB and LPZ, and to personnel in the Control Room and TSC .

which is the dose criteria specified in 10 CFR 50.67 (Reference 1).

2.3 Technical Specification Bases Changes The TS Bases will be revised to reflect the licensing basis changes outlined in Section 2.1 and the TS changes identified in Section 2.2. A markup of the TS Bases changes is provided for information only in Attachment 3 to this Enclosure.

These TS Bases changes will be implemented in accordance with TS 5.5 .14, "Technical Specification (TS) Bases Control Program, " upon NRC approval of this LAR.

2.4 Plant Changes The following plant design modifications will be performed as part of AST implementation. These plant modifications support the AST analyses provided in Attachment 4.

  • Install shielding material, equivalent to that provided by the Control Room outer walls, at the external concrete west wall of the Control Room briefing room.
  • Install a high efficiency particulate air filter (HEPA) in the TSC normal ventilation system intake.
  • Update setpoints for the redundant safety related gamma sensitive area radiation monitors (1-RE 25/26, 2-RE 25/26). These monitors are located at the Control Room normal intakes and are designed to automatically isolate the normal CRVS intakes and shift to CRVS Mode 4 (pressurized filtered emergency ventilation) . These monitors are relied upon to perform their design function following a FHA in the FHB or Containment.

Setpoints for these monitors are contained in the Offsite Dose Calculation Manual, which is controlled by TS 5.5.1, requirements.

  • Reclassify a portion of the 40-inch Containment Penetration Area (GE/GW) Ventilation line from PG&E Design Class II to PG&E Design Class I and upgrade the damper actuators, pressure switches , and the damper solenoid valves to PG&E Design Class I. See Attachment 4, Section 5.2 for further details.
  • Reclassify a portion of the 2 inch gaseous radwaste system line which connects to the Plant Vent as PG&E Design Class I. This line is currently 14

Enclosure Attachment 1 PG&E Letter DCL-16-061 Enclosure PG&E Letter DCL-15-069 classified as PG&E Design Class II. See Attachment 4, Section 5.2 for further details.

2.5 Procedure Changes As part of AST implementation , the following procedural updates will include:

  • Update Equipment Control Guideline (ECG) 42.1, "Refueling Operations -

Decay Time," to lower the restriction on fuel movement from 100 hours0.00116 days <br />0.0278 hours <br />1.653439e-4 weeks <br />3.805e-5 months <br /> to 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br /> post-shutdown.

  • Update ECG 42 .5, "Refueling Operations - Water Level - Reactor Vessel (Control Rods)" to reflect the FHA AST analysis assumptions.
  • Update ECG 23 .3, "Containment Ventilation System ," to reflect changes to TS 3.6.3.
  • Review and update, as necessary, the EOPs and operator training procedures to ensure that the requisite steps to select the least contaminated CRVS pressurization intake are in use throughout the event.

This review is to be performed as verification , since the EOPs currently include steps to select the least contaminated CRVS intake.

  • Update Surveillance Test Procedure M-57, "Control Room Ventilation System (CRVS) Tracer Gas Test," to include the new Control Room inleakage test acceptance criteria and the range of CRVS ventilation flows deemed acceptable by the AST dose consequence analyses.
  • Update the TSC administrative procedures to ensure that:
a. The nominal normal operation TSC ventilation air intake flowrate is 500 cubic feet per minute (cfm).
b. Following a LOCA, the TSC will be manually placed in Mode 4 operation such that filtered pressurization and recirculation can be credited within 2 hours2.314815e-5 days <br />5.555556e-4 hours <br />3.306878e-6 weeks <br />7.61e-7 months <br /> of accident initiation.
c. The nominal post-LOCA TSC ventilation filtered pressurization and recirculation flowrates are 500 cfm, respectively.
  • Review EOPs to verify valve alignment information to manually initiate containment spray in the recirculation mode. Update EOPs to include direction to perform the realignment action within 12 minutes of termination of injection spray to ensure that the duration of spray operation (injection plus recirculation) exceeds 6 .25 hours2.893519e-4 days <br />0.00694 hours <br />4.133598e-5 weeks <br />9.5125e-6 months <br /> following the event. An associated TCOA will be implemented .
  • Update ESF system leak testing procedures that are controlled by TS 5.5.2 , "Primary Coolant Sources Outside Containment, " to establish administrative acceptance criteria to ensure:

15

Enclosure Attachment 1 PG&E Letter DCL-16-061 Enclosure PG&E Letter DCL-15-069 revised to require the 48-inch containment purge supply and exhaust valves to be sealed closed during operation MODES 1, 2, 3, and 4 eliminating a potential dose contribution release path , the accident induced leakage performance criterion for the steam generator tube inspection program is revised to be more restrictive, and the testing requirement for the auxiliary building ventilation system charcoal filter is also revised to be more restrictive. Other changes to the TSs involve the adoption of terminology on which AST is based .

AST methods have been utilized in the analysis of the limiting design basis accidents, as follows: loss of coolant accident (LOCA) , fuel handing accident (FHA) in the containment and in the fuel handling building, locked rotor accident (LRA), control rod ejection accident (CREA) , main steam line break (MSLB) , and steam generator tube rupture (SGTR) . AST methods have also been utilized in the analysis of the limiting Condition II event, the loss of load (LOL) accident.

Other changes incorporated in the revised analyses include revising atmospheric dispersion factors (x/0) , reducing the minimum decay time before fuel movement, adding shielding to the Control Room for additional protection of Control Room personnel and adding a high efficiency particulate air (HEPA) filter for additional protection of TSC personnel. In addition , a portion of the 40-inch Containment Penetration Area Ventilation line and a portion of the 2 inch gaseous radwaste system line which connects to the Plant Vent areis being reclassified from PG&E Design Class II to PG&E Design Class I. Because AST methodologies better represent the physical characteristics and timing of the radionuclide release following a postulated LOCA, containment spray is now relied upon during the recirculation of sump water for continued removal of iodine and particulate from the containment atmosphere for spray duration (injection plus recirculation) greater than 6.25 hours2.893519e-4 days <br />0.00694 hours <br />4.133598e-5 weeks <br />9.5125e-6 months <br />. In addition , setpoint changes are being made to the Control Room intake radiation monitors to incorporate the effect of all possible release points from a FHA.

PG&E has evaluated whether or not a significant hazards consideration is involved with the proposed amendment 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.

This license amendment does not physically impact any system , structure ,

or component (SSC) that is a potential initiator of an accident. Therefore ,

implementation of AST, the AST assumptions and inputs, the proposed TS changes, and new xlO values have no impact on the probability for initiation of any design basis accident. Once the occurrence of an accident has been postulated , the new accident source term and x!O 27

Enclosure Attachment 1 PG&E Letter DCL-16-061 Enclosure PG&E Letter DCL-15-069 values are inputs to analyses that evaluate the radiological consequences of the postulated events.

Reactor coolant specific activity, testing criteria of charcoal filters , and the accident induced primary-to-secondary system leakage performance criterion are not initiators for any accident previously evaluated . The proposed change to require the 48-inch containment purge valves to be sealed closed during operating MODES 1, 2, 3, and 4 is not an accident initiator for any accident previously evaluated . The change in the classifications of a portion of the 40-inch Containment Penetration Area Ventilation line and a portion of the 2 inch gaseous radwaste system line is also not an accident initiator for any accident previously evaluated .

Thus, the proposed TS changes and AST implementation will not increase the probability of an accident.

The change to the decay time prior to fuel movement is not an accident initiator. Decay time is used to determine the source term for the dose consequence calculation following a potential FHA and has no effect on the probability of the accident. Likewise, the change to the Control Room radiation monitors setpoint cannot cause an accident and the operation of containment spray during the recirculation phase is used for mitigation of a LOCA, and thus not an accident initiator.

As a result, there are no proposed changes to the parameters or conditions that could contribute to the initiation of an accident previously evaluated in Chapter 15 of the Updated Final Safety Analysis.Report (UFSAR) . As such , the AST cannot affect the probability of an accident previously evaluated.

Regarding accident consequences, equipment and components affected by the proposed changes are mitigative in nature and relied upon once the accident has been postulated. The license amendment implements a new calculation methodology for determining accident consequences and does not adversely affect any plant component or system that is credited to mitigate fuel damage. Subsequently, no conditions have been created that could significantly increase the consequences of any accidents previously evaluated.

Requiring that the 48-inch containment purge supply and exhaust valves be sealed closed during operating MODES 1, 2, 3, and 4 eliminates a potential path for radiological release following events that result in radioactive material releases to the containment, thus reducing potential consequences of the event. The steam generator tube inspection testing criterion for accident induced leakage is being changed , resulting in lower leakage rates , and thus less potential releases due to primary-to-28

Enclosure Attachment 1 PG&E Letter DCL-16-061 Enclosure PG&E Letter DCL-15-069 secondary leakage. The auxiliary building ventilation system allowable methyl iodide penetration limit is being changed , which results in more stringent testing requirements , and thus higher filter efficiencies for reducing potential releases.

Changes to the operation of the containment spray system to require operation during the recirculation mode are also mitigative in nature.

While the plant design basis has always included the ability to implement containment spray during recirculation , this license amendment now requires operation of containment spray in the recirculation mode for dose mitigation. DCPP is designed and licensed to operate using containment spray in the recirculation mode. As such , operation of containment spray in the recirculation mode has already been analyzed, evaluated , and is currently controlled by Emergency Operating Procedures. Usage of recirculation spray reduces the consequence of the postulated event.

Likewise , the additional shielding to the Control Room and the addition of a HEPA filter to the TSC ventilation system reduces the consequences of the postulated event to the Control Room and TSC personnel. Lowering the limit for DEX lowers potential releases. By reclassifying a portion of the 40-inch Containment Penetration Area Ventilation line and a portion of the 2 inch gaseous radwaste system line to PG&E Design Class I, th isese lines will be seismically qualified , thus assuring that post-LOCA release points are the same as those used for determining x!O values .

The change to the decay time from 100 hours0.00116 days <br />0.0278 hours <br />1.653439e-4 weeks <br />3.805e-5 months <br /> to 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br /> prior to fuel movement is an input to the FHA Although less decay will result in higher released activity, the results of the FHA dose consequence analysis remain within the dose acceptance criteria of the event. Also, the radiation levels to an operator from a raised fuel assembly may increase due to a lower decay time, however, any exposure will continue to be maintained under 10 CFR 20 limits by the plant Radiation Protection Program .

Plant-specific radiological analyses have been performed using the AST methodology, assumption and inputs, as well as new x!O values. The results of the dose consequences analyses demonstrate that the regulatory acceptance criteria are met for each analyzed event.

Implementing the AST involves no facility equipment, procedure, or process changes that could significantly affect the radioactive material actually released during an event. Subsequently, no cond itions have been created that could significantly increase the consequences of any of the events being evaluated .

29

Enclosure Attachment 3 PG&E Letter DCL-16-061 ATTACHMENT 3 Replacement Markup Page for Diablo Canyon Power Plant Updated Final Safety Analysis Report Markup (For Information Only)

Enclosure Attachment 3

& PG&E Letter DCL-16-061 DCPP UNITS 1 & 2 FSAR UPDATE degrees azimuth with the use of ARCON96, as described in Regulatory Position C.3 .3.2 of Regulatory Guide 1.194, June 2003.

Redundant Radiation Monitors Per Regulatory Guide 1.194,,June 2003 , Regulatory Position C.3.3.2 .3, based on the dual intake design of the control room pressurization intakes, and the availability of redundant PG&E Design Class I radiation monitors at each pressurization intake (which provide the capability of initial selection of the cleaner intake and support the expectation that the operator will manually make the proper intake selection throughout the event) , allows the x!O values applicable to the more favorable control room pressurization intake to be reduced by a factor of 4 and utilized to estimate the dose consequences.

PG&E Design Class II Lines Connecting to PG&E Design Class I Plant Vent The 16 inch PG&E Design Class II gland seal steam exhauster line and the 2-inch PG&E Design Class II gas decay tank vent line connect to the PG&E Design Class I plant vent. In addition, the plant vent expansion joint may experience a tear during a seismic event, however the plant vent will remain intact and functional.

a) The gland seal steam 16 inch exhauster line connects to the plant vent at El 144'-6" (Centerline) on the North-East side I South-East side of the Unit 1 and Un it 2 containments, res ectively. The 2-inch gas decay tank vent line connects to the plant vent at El 137'-6" on the North-East side I South-East side of the Unit 1 and Unit 2 containments, respectively.

b) The plant vent expansion joint is located at El 155.83' North-East side I South-East side of the Unit 1 and Unit 2 containments , respectively. As discussed earlier, the plant vent expansion joint may experience a tear during a seismic event.

An assessment of the potential release locations identified above indicates that the x/O values developed for the plant vent are either conservative or representative of these potential release points.

Release points and receptor locations are provided in Figure 2.3-5, while Table 2.3-146 provides the release point I receptor combinations that were evaluated . Tables 2.3-147 and 2.3-148 provide the control room x!O values for the individual release point-receptor combinations for Unit 1 and Unit 2, respectively.

The x!O values selected for use in the dose consequence analyses are intended to support bounding analyses for an accident that occurs at either unit. They take into consideration the various release points-receptors applicable to each accident in order to identify the bounding x!O values and reflect the allowable adjustments and reductions in the values as discussed earlier and further summarized in the notes of Tables 2.3-147 and 2.3-148 .

2.3-34 Revision 21 September 2013

Enclosure Attachment 4 PG&E Letter DCL-16-061 ATTACHMENT 4 Replacement Markup Page for Supplement to License Amendment Request 15-03, "Application of Alternative Source Term," dated August 31, 2015

Enclosure Attachment 4 PG&E Letter DCL-16-061 Document Control Desk PG&E Letter DCL-15-105 August 31 , 2015 Page 2

2. Please provide a license condition indicating that the modifications will be completed in support of the commitments made in Attachment 7 of the LAR.

During the clarification call on July 28 , 2015 , the licensee stated that these modifications will be implemented prior to application of the amendment.

The Enclosure to this letter contains summary information in response to the NRC's first request listed above. Additional detailed information on changes made to the thermal-hydraulic analysis from the CLB to the AST analysis, in addition to that previously contained in Appendix B of Attachment 4 of the LAR 15-03, will be submitted by September 30 , 2015.

In response to the NRC's second request listed above, PG&E proposes the following license condition to support application of AST:

Upon implementation of the amendment adopting the alternative source term , the following plant modifications will be complete:

  • Install shielding material , equivalent to that provided by the Control Room outer walls, at the external concrete west wall of the Control Room briefing room prior to implementation of Alternate Source Term .
  • Re-classify a portion of the 40-inch Containment Penetration Area (GE/GW)

Ventilation line from PG&E Design Class II to PG&E Design Class I and upgrade the damper actuators , pressure switches , and the damper solenoid valves to PG&E Design Class I prior to implementation of Alternate Source Term .

  • Re classify a portion of the 2 inch gaseous radwaste system line which connects to the Plant Vent as PG&E Design Class I prior to implementation of Alternate Source Term.
  • Update setpoints for the redundant safety related gamma sensitive area radiation monitors (1-RE 25/26, 2-RE 25/26) prior to implementation of Alternate Source Term . to the Enclosure of this letter contains the proposed markup for the license conditions in Appendix D of the Unit 1 and 2 operating licenses. The plant modifications contained in Attachment 1 to the Enclosure were previously proposed as license commitments one through five in Attachment 7 to the Enclosure of Reference 1. Since the modifications are being proposed as license conditions, the commitments one through five previously provided in Attachment 7 to the Enclosure of Reference 1 are deleted.

A member of the STARS (Strategic Teaming and Resource Sharing) Alliance Callaway

  • Diablo Canyon
  • Palo Verde
  • Wolf Creek

Enclosure Attachment 5 PG&E Letter DCL-16-061 ATTACHMENT 5 Updated Insert #1 for the License Conditions in Appendix D of the Unit 1 and 2 Operating Licenses

Enclosure Attachment 5 PG&E Letter DCL-16-061 Enclosure Attachment 1 PG&E Letter DCL-15-105 Insert #1 xxx Implementation of the amendment adopting the The amendment is alternative source term shall include the effective as of the date of following plant modifications: its issuance and the condition shall be implemented within 365 days of its issuance Install shielding material , equivalent to that provided by the Control Room outer walls, at the external concrete west wall of the Control Room briefing room.

Install a high efficiency particulate air filter in the Technical Support Center normal ventilation system.

Re-classify a portion of the 40-inch Containment Penetration Area (GE/GW)

Ventilation line from PG&E Design Class II to PG&E Design Class I and upgrade the damper actuators, pressure switches, and the damper solenoid valves to PG&E Design Class I.

Update setpoints for the redundant safety related gamma sensitive area radiation monitors (1-RE 25/26 , 2-RE 25/26).

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