ML110910132
| ML110910132 | |
| Person / Time | |
|---|---|
| Site: | Diablo Canyon  |
| Issue date: | 03/31/2011 |
| From: | Pacific Gas & Electric Co |
| To: | Office of Nuclear Reactor Regulation |
| Polickoski J, NRR/DORL/LPL4, 415-5430 | |
| Shared Package | |
| ML110910125 | List: |
| References | |
| TAC ME5033, TAC ME5034 | |
| Download: ML110910132 (3) | |
Text
DRAFT DCPP Long Term Seismic Program Update Evaluation of Updated Seismic Hazard Information Flowchart A - Overview Updated LTSP Seismic Hazard Input Information Received by DCPP (2) or Ten Years Since Prior Update (1)
See Flowchart C
See Flowchart B
Submit Peer-Reviewed Updated LTSP Information to Nuclear Regulatory Commission (NRC) /
Nuclear Reactor Regulation (NRR)
Restart 10 Year Interval Notes:
(1) Update to be performed at less than a 10 year interval if significant new information becomes available. The start of each interval to be based on submittal date of prior update.
(2) Seismic Hazard Input is developed by the PG&E Geosciences Department. Types of input include seismic hazard curves, deterministic ground motion response spectrum, source characterization, ground motion spectral shapes, etc.
(3) Seismic Margins Assessment based on deterministic ground motion response spectrum.
(4) Seismic Hazard Curves are typically available within 30 days.
DRAFT (03-29-2011)
Seismic Probabilistic Risk Assessment Confirmatory Path Used for Safety Risk Assessment (cannot start until seismic hazard curves are available (4) and typically, the assessment will take 6 months to complete)
Seismic Margins Assessment Primary Path Used for Operability Determination (to be performed within 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> of receipt of data) (3)
Process for Updates to the Long Term Seismic Program (LTSP)
Seismic Probabilistic Risk and Seismic Margins Assessment (to be performed on a 10 year interval) (1)
DRAFT DCPP Long Term Seismic Program Update Evaluation of Updated Seismic Hazard Information Flowchart B - Seismic Margins Assessment Is Min. Seismic Margin > 1.0
?
DRAFT (03-29-2011)
Notes:
(1) The Deterministic Ground Motion Response Spectrum (DGMRS) is developed by the PG&E Geosciences Department in accordance with peer-reviewed methodologies.
(2) Changes in the DGMRS may impact the in-structure response spectra, which are an input to the High Confidence Low Probability of Failure (HCLPF) capacities of Structures, Systems, and Components (SSCs).
(3) The HCLPF capacities are based on the methodologies defined in EPRI NP-6041-SL.
(4) The 1991 LTSP DGMRS is that defined in the 1988 LTSP Final Report, as modified by the NRC in SSER-34 (1991).
(5) Update required if the Updated DGMRS exceeds the 1991 LTSP DGRMS at any frequency.
(6) Update required if the Updated DGMRS exceeds the design basis 1977 Hosgri Earthquake response spectrum, as defined in in the DCPP Updated Final Safety Analysis Report, Section 2.5, at any frequency (7) The 1991 LTSP DGMRS and/or the 1977 Hosgri RS may be updated based new information subsequent to NRC approval of a License Amendment.
Is Updated DGMRS Enveloped by 1991 LTSP DGMRS(4)
?
Do Changes to DGMRS Require Updated High Confidence Low Probability of Failure (HCLPF)
Capacities (2)
?
No Update HCLPF Capacities for Impacted Structures, Systems, and Components (SSCs) (3)
Reassess Plant Seismic Margins for Impacted Structures, Systems, and Components (SSCs) with Updated DGMRS, HCLPF Capacities No No Enter Tech. Spec. Limiting Condition for Operation (LCO) for Impacted SSC(s)
Develop Modifications to Restore Seismic Margins (SSC(s) Inoperable)
Document Updated LTSP DGMRS (7),
Hosgri RS(7), HCLPF Capacities, Seismic Margins in DCPP Records Yes Entry Point from Flowchart A Yes Return to Flowchart A Submit License Amendment Request to Update 1991 LTSP DGMRS (5) and/or 1977 Hosgri Response Spectrum (RS) (6)
Updated Seismic Hazard Information for Seismic Margins Assessment (SMA) Received by DCPP or 10 Year Update
- Updated Deterministic Ground Motion Response Spectrum (DGMRS) (1)
Yes Update HCLPF Capacities for Impacted Structures, Systems, and Components (SSCs) (3),
if required
DRAFT DCPP Long Term Seismic Program Update Evaluation of Updated Seismic Hazard Information Flowchart C - Seismic Probabilistic Risk Assessment Conduct SPRA to Determine Seismic Core Damage Frequency (SCDF)
With
- Updated Input Information (3)
- Updated Methodologies (2), (4)
Document Updated SHC, GMSS, Fragilities, and SCDF in DCPP Records Notes:
(1) The Seismic Hazard Curves (SHC) and Ground Motion Spectral Shape (GMSS) are developed by the PG&E Geosciences Department in accordance with peer-reviewed methodologies.
(2) The Seismic Probabilistic Risk Assessment (SPRA) will be based on Capability Category II of ASME/ANS RA-Sa-2009, as modified by Reg. Guide 1.200.
(3) Input information includes seismic hazard curves, ground motion spectral shape, and fragilities.
(4) Fragilities are based on the shape of the ground motion spectral shape and peer-reviewed fragility calculation methods (ASME/ANS RA-Sa-2009, as modified by Reg. Guide 1.200, EPRI TR-103958, 1002988, 1019200)
DRAFT (03-29-2011)
Notify Nuclear Regulatory Commission (NRC)
Entry Point from Flowchart A Updated Seismic Hazard Information for Seismic Probabilistic Risk Assessment (SPRA)
Received by DCPP or 10 Year Update
- Updated Seismic Hazard Curve (SHC) (1)
- Updated Ground Motion Spectral Shape (GMSS) (1)
Return to Flowchart A