ML15029A094

Alternate Source Term Pre- Submittal Meeting on February 3, 2015 (TAC Nos. MF5596 and MF5597). AST LAR NRC Meeting Presentation

ML15029A094
Person / Time
Site:	Diablo Canyon
Issue date:	02/03/2015
From:	Ashley K, Bryan M, Schrader K AREVA, CB&I, Pacific Gas & Electric Co
To:	Plant Licensing Branch IV
Lingam S
References
TAC MF5596, TAC MF5597
Download: ML15029A094 (27)

Text

1 1 1

DIABLO CANYON POWER PLANT Pre-application Meeting, Alternative Source Term License Amendment Request February 3, 2015 Ken Schrader Regulatory Services Pacific Gas & Electric Co.

Avila Beach, CA kjse@pge.com 805-545-4328 Sreela Ferguson, CB&I Marty Bryan, AREVA Kathy Ashley, AREVA

2 2 Agenda Diablo Canyon Power Plant (DCPP) Current Radiological Analysis Licensing Basis Issues to be Resolved by License Application Request (LAR)

Alternative Source Term (AST) Analyses Summary AST Impact on Other Analyses Precedent

Agenda (cont.)

Tech Spec (TS) Changes Documentation Changes PG&E Questions Staff Feedback 3

4 4 DCPP Current Licensing Basis AST Partial Implementation Fuel Handling Accident (FHA) in the Fuel Handling Building SER 163 and 165 to support changes to safety related ventilation filter testing program TID-14844 Source Terms All other post-accident dose consequence analyses Radiological Equipment Qualification (EQ)

Post-LOCA Operator Vital Area Mission Doses

DCPP Current Licensing Basis (cont.)

Assumptions similar to NUREG 0800 Loss of Coolant Accident (LOCA)

Main Steam Line Break (MSLB)

Steam Generator Tube Rupture (SGTR)

FHA in the Containment 5

DCPP Current Licensing Basis (cont.)

Pre-NUREG 0800, DCPP-Specific / No Control Room Dose Assessment Control Rod Ejection Accident (CREA)

Locked Rotor Accident (LRA)

Loss-of Load (LOL) Event 6

DCPP Current Licensing Basis (cont.)

RG 1.183 Iodine Release Rate Multiplier SGTR (X 335)

Dose Conversion Factors Different accidents use different dose conversion factors Technical Support Center (TSC) Habitability for LOCA per NUREG-0737, Supplement 1 Operation of Containment Spray during recirculation mode controlled by EOPs/TSC 7

8 8 Issues to Be Resolved by LAR Licensing Basis Verification Project Voluntarily initiated by DCPP Identified issues (addressed in Corrective Action Program)

Atmospheric dispersion factors methodology Post-accident environmental release points Containment purge system releases during LOCA Incorporate recent Control Room Tracer Gas Test Results

Proposed Changes to DCPP Licensing Basis Full Implementation of AST Remove dose contribution of a containment purge following a LOCA for purposes of hydrogen control per revised 10CFR50.44 Remove expected accident dose assessments that were part of original license application Remove dose contribution to the CR operator during daily commute from site boundary to CR following a LOCA 9

AST Analyses Summary Analyzed Events Loss of Coolant Accident (LOCA)

FHA in the Containment FHA in the Fuel Handling Building (reanalysis)

Locked Rotor Accident (LRA)

Control Rod Ejection Accident (CREA)

Main Steam Line Break (MSLB)

Steam Generator Tube Rupture (SGTR)

Loss-of Load (LOL) Event 10

11 11 AST Analyses Summary (cont.)

DCPP followed the guidance of RG 1.183, with two exceptions Non-LOCA Gap Fractions (other than CREA)

Bounding values per isotope/isotope class provided in:

RG 1.25 NUREG/CR 5009 RG 1.183 FHA analyzed without concurrent loss of offsite power per guidance provided in IN 93-17, R1

12 12 AST Analyses Summary (cont.)

Other aspects of AST analyses Update of computer codes Use of dose conversion factors (DCFs) from Federal Guidance Report (FGR) No. 11 & 12, as appropriate, for all design basis accidents New offsite (per RG 1.145) and Control Room (ARCON 96) X/Q factors Meteorological data from 2007 to 2011

AST Analyses Summary (cont.)

Control Room Model Updated CR ventilation system parameters due to new back-draft damper in CR emergency filter recirculation lines Updated CR unfiltered inleakage based on 2012 CR Tracer Gas Test Credit for CR dual intake ventilation design 13

14 14 AST Analyses Summary (Cont.)

LOCA Analysis Credit for Containment Spray in Recirculation Mode Until ~6.25 hours2.893519e-4 days <br />0.00694 hours <br />4.133598e-5 weeks <br />9.5125e-6 months <br /> Manual Initiation Updated Engineered Safety Features system leakage values and release points Elimination of Containment Purge Pathway for Hydrogen Control

15 15 AST Analyses Summary (Cont.)

FHA Credit for automatic initiation of CR emergency ventilation by safety related radiation monitors located at CR normal ventilation intake Minimum decay time prior to fuel movement reduced 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 /> MSLB, SGTR, LRA, CREA, LOL Event Primary to secondary leakage is assumed to be a total of 0.75 gpm from all steam generators (equivalent to 1080 gallons per day)

TS limit is 150 gallons per day from any one steam generator

AST Impact on Other Analyses Radiation Environments for EQ Continues to be based on TID-14844 source terms Per NUREG-0933, "Resolution of Generic Safety Issues", Section 3.0, Item 187 No discernible risk reduction associated with adopting AST for EQ Radiation environments for EQ in ESF HVAC filter cubicles will be evaluated for effect of reanalysis Effect of CS in recirculation mode already incorporated in DCPP EQ radiation environments 16

AST Impact on Other Analyses (Cont.)

Post-LOCA Vital Area Mission doses Continues to be based on TID-14844 source terms Per AST benchmarking study in SECY-98-154 TID-14844 more limiting earlier on in the event TSC Habitability Evaluated for LOCA using AST 17

18 18 AST Precedent AST Submittals in General Many AST submittals and approvals Containment Spray during Recirculation DCPP already licensed for CS operation in Recirculation Mode Salem Units 1 and 2 Non-LOCA Gap Fractions Millstone Indian Point

AST Precedent Use of CB&I Proprietary Codes (next slide)

Beaver Valley Fort Calhoun CE System 80+ Design Certification 19

CB&I Stone & Webster Proprietary Codes Code Task Precedent with AST Applications*

ACTIVITY2 Reactor coolant activity inventory Beaver Valley Fort Calhoun IONEXCHANGER Secondary coolant activity inventory Beaver Valley Fort Calhoun EN-113 EAB and LPZ atmospheric dispersion factors, follows RG 1.145 methodology Fort Calhoun SWNAUA Particulate aerosol removal coefficients Beaver Valley Fort Calhoun CE System 80+ Design Cert PERC2 Shine dose energy release rates and gamma energy releases, source terms for SW-QADCGGP Beaver Valley Fort Calhoun CE System 80+ Design Cert SW-QADCGGP Direct shine dose to control room and EAB Beaver Valley Fort Calhoun 20

• The listed codes have been used extensively by CB&I Stone & Webster in licensing applications supporting original licensing, as well as modifications to nuclear power plant design, and their results have been accepted by NRC.

21 21 Tech Spec Changes TS 1.1, Definition of Dose Equivalent I-131 Revised to only reference Table 2.1 of FGR 11 for dose conversion factors Consistent with RIS 2006-04, item 10 Consistent with TSTF-490 TS 3.4.16, RCS Specific Activity Reduce Dose Equivalent XE-133 from 600

µCi/gm to 270 µCi/gm Equivalent to ~0.5% fuel defects

22 22 Tech Spec Changes (Cont.)

TS 3.6.3, Containment Isolation Valves Currently allows operating 48-in containment purge supply and exhaust valves during Modes 1 through 4 under administrative controls Revised to require these 48-in valves closed and deactivated during Modes 1 through 4 Eliminates potential release path following LOCA Consistent with Standard TSs

Tech Spec Changes (Cont.)

TS 5.5.11, Ventilation Filter Testing Program Revise allowable methyl iodine penetration testing criteria for Auxiliary Building Ventilation system charcoal filter from 15% to 5%

Value used to determine charcoal filter efficiency for removing iodine from atmospheric releases Filtration credit only taken for offsite dose from Residual Heat Removal (RHR) pump seal passive failure following a LOCA. CR dose does not credit filtration.

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24 24 Tech Spec Changes (Cont.)

TS 5.5.19, Control Room Envelope Habitability Program Replace whole body or its equivalent to any part of the body to TEDE.

25 25 Documentation Changes TS Bases FSAR Procedures

PG&E Questions Requesting staff feedback on Proposed changes to licensing basis (Slide 9)

Planned RG 1.183 exceptions (Slide 11)

Non-LOCA Gap Fractions Analyzing FHA without concurrent loss of offsite power 26

27 27 27 Staff Feedback Staff Feedback