ML13044A735

Licensee Slides from 2/12/13 Public Meeting to Discuss License Amendment Requests for Degraded Voltage Protection and Control Room Dose Analysis of Record at Diablo Canyon, Units 1 and 2

ML13044A735
Person / Time
Site:	Diablo Canyon
Issue date:	02/12/2013
From:	Stephen Baker, Ballard J, Gibbons D, Soenen P Pacific Gas & Electric Co
To:	Plant Licensing Branch IV
Polickoski J
References
TAC ME0545, TAC ME0546
Download: ML13044A735 (12)

Text

Diablo Canyon Power Plant Pre-application Meeting, Degraded Voltage Protection LAR Revision and new LAR for AST Dose Consequence Analyses Steve Baker Jerry Ballard Dan Gibbons Philippe Soenen Pacific Gas & Electric Co.

February 12, 2013 1

Agenda Objectives Description of NonConforming Conditions Options Considered Plan for Resolution Questions and Feedback 2

Objectives Present resolution plan to allow timely correction of:

- Nonconservative first level undervoltage relays (FLUR) technical specification (TS)

- Nonconforming FSAR accident analysis

- Nonconforming control room dose analysis 3

Degraded Voltage Protection NonConforming Conditions Two violations received during a 2010 Component Design Basis Inspection (Reference ML102040823) were related to the following requirements:

- The allowable time duration of a degraded voltage condition at all distribution system levels shall not result in failure of safety systems or components;

- A postulated scenario could have resulted in ESF pump motors tripping overcurrent relays due to sustained degraded voltage

- "The allowable second level undervoltage relay time delay, including margin, shall not exceed the maximum time delay that is assumed in the Final Safety Analysis Report Update accident analyses.

4

Original Scope of Degraded Voltage Protection LAR

• Addressed both violations on the previous slide

• Revise Technical Specification 3.3.5 Loss of Power (LOP) Diesel Generator (DG) Start Instrumentation to correct nonconservative TS values

• Revise the FSAR Update to increase ESF component delay times used in accident analyses to bound the maximum Second Level Undervoltage Relay (SLUR) actuation time delay.

• Revise Control Room loss of coolant accident (LOCA) dose AOR to bound the maximum SLUR actuation time delay.

• Addressed both violations together because of similarities. Revisions to the FLUR TS are independent of the SLUR time delay.

• LAR withdrawn after additional LOCA Dose AOR nonconforming conditions were identified (September 2012).

5

Additional LOCA Dose AOR NonConforming Conditions Identified after submittal of the degraded voltage protection LAR

- Addressed via corrective action program and prompt operability assessment.

1. Unapproved Atmospheric Dispersion Factors (X/q)

- Identified by PG&E License Basis Verification Project

2. Nonconservative analysis assumptions, including:

a. Release points for PostLOCA Containment and ECCS leakage sources

b. Auxiliary Building Ventilation System (ABVS) Charcoal Filter Efficiency and bypass flow

c. Containment purge releases

d. RWST backleakage

e. CRVS charcoal filter shine

3. CRVS filter bypass on single failure of a booster fan 6

Options Considered Option 1 (PG&E proposal)

Submit a FLUR LAR to address the nonconservative Technical Specification only (a subset of Degraded Voltage Protection LAR). (Est. June 2013)

Submit a LAR for approval of Full Implementation of alternate source term (AST) Methodology with updated Dose Consequence Analyses. (Est. Mid 2014)

- Include evaluation and FSAR Update to increase ESF component delay times used in accident analyses to bound the maximum SLUR actuation time delay.

Option 2 Resubmit a single LAR that addresses the scope of the original degraded voltage LAR. This LAR will also include full Implementation of AST Methodology with updated Dose Consequence Analyses for LOCA, FHA, MSLB, SGTR, LR and CREA (Est. Mid 2014) 7

Changes from Previously Submitted Degraded Voltage Protection LAR PG&E is considering adding an upper limit to the TS.

• Option 1 - Revise FLUR portion of the Tech Spec to add an upper limit with a commitment to revise the SLUR when the AST LAR is submitted.

• Option 2 - Revise FLUR and SLUR Tech Specs to add an upper limit at the same time.

8

Resolution Plan Advantages of Option 1 - FLURonly LAR followed by AST/ SLUR time delay LAR Allows correction of nonconservative FLUR TS to proceed while longer term AST analyses are performed, submitted, and approved.

AST analyses, while requiring additional time to develop, will result in increased operating margin in the long term 9

Resolution Plan continued AST Analysis Proposed Approach Adopt AST methodology to determine offsite and control room dose consequences for the following DBAs

• LOCA

• Fuel Handling Accident (Containment and FHB)

• Main Steam Line Break

• Steam Generator Tube Rupture

• Locked Rotor

• Control Rod Ejection RG 1.183 and ARCON96 X/q methods 10

Conclusions Resolution PG&E currently plans to pursue Option 1:

- Submit a FLUR LAR to address the nonconservative Technical Specification.

(June 2013)

- Submit a LAR for approval of Full Implementation of AST Methodology with updated Dose Consequence Analyses for the LOCA, FHA, MSLB, SGTR, LR and CREA . Documentation addressing SLUR time delay impacts on safety analyses will be included.

(Mid 2014) 11

Staff Feedback 12