ML17187A574
| ML17187A574 | |
| Person / Time | |
|---|---|
| Site: | Perry  |
| Issue date: | 06/29/2017 |
| From: | FirstEnergy Nuclear Generation |
| To: | Kimberly Green Plant Licensing Branch III |
| Green K | |
| References | |
| CAC MF9777 | |
| Download: ML17187A574 (16) | |
Text
FENOC - NRC Pre-Submittal Meeting Proposed Request for Licensing Action Perry Flood Hazards June 29, 2017
FENOC - NRC Pre-Submittal Meeting Proposed Request for Licensing Action Perry Flood Hazards
Introductions
Meeting Purpose Site Design Basis External Flood Hazard Reconstitution direction and scope of License Amendment Request Topics for todays discussion History Flood Hazards Proposed Licensing Action Scope Requested Licensing Action 6/29/2017 2
FENOC Representatives Ben Huck, Manager - Design Engineering Tom Lentz, Manager - Fleet Licensing Phil Lashley, Supervisor - Fleet Licensing Mark Bensi, Design Engineering John Sabo, Design Engineering Steve Osting, Project Manager Kathy Nevins, Fleet Licensing 6/29/2017 3
History March 12, 2012; April 11, 2013; March 10, 2015; NRC Issues Prompt Rev. 0 Flood 50.54(f) letter Functionality Hazard Re-Assessment evaluation Report Condition Report (FHRR) Submitted 2013-05625, Updated by CR 2015-05079 and 2015-08036 November 3, 2015; March 24, 2016; July 25, 2016; July 25, 2017; New Diversion Rev. 1 Flood NRC Interim Staff Submittal to NRC of Channel and Hazard Re- Response -Flood Mitigating Stream evaluation Report Hazard Re-Strategies Modifications, Field Submitted evaluation Report Implemented Audit Assessment Summary Document 6/29/2017 4
6/29/2017 5 Flood Hazards Dam Breaches and Failures No traditional dams in Perry watershed Storm Surge and Seiche Passively protected by bluff height Tsunami - N/A Ice-Induced Flooding - N/A, High bluffs, stream ice blockage bounded by all-season event Channel Migration or Diversion - N/A No cooling water channels exist Flooding in Streams and Rivers New diversion channel installed Railroad embankment removed for major stream Secondary access road raised LIP Reevaluation of LIP remains a challenge 6/29/2017 6
Proposed Request for Licensing Action Scope All hazards with the exception of LIP have been mitigated.
Site drainage Items required for Design Basis LIP analyses and mitigation in proposed licensing action scope:
Technical Specification for time-based warning protection Incorporated barriers for mitigation of LIP event FLO-2D computer program Credit all building exteriors as flood boundaries Credit plant storm system 6/29/2017 7
Time-Based Warning Protection (License Amendment Request)
Provide Hardened Protection for all events up to and including the Standard Project Storm/Standard Project Flood (SPF)
Standard Project Storm (SPS) for PNPP determined to be 28.4% of PMP SPS determined using the guidance of EM 1110-2-1411 SPS process provides an event reasonably characteristic of the region SPF results will be developed using process consistent with LIP PMF (FLO-2D)
Technical Specification to provide limiting condition for operations for potential flood conditions Proceduralized response for events in excess of SPS/SPF Advanced warning to be received from FE Meteorology Dept.
Warning response to be incorporated into plant procedures Plant personnel to deploy temporary incorporated barriers Similar to approach adopted for Beyond Design Basis hazards Similar in concept to Regulatory Position 2 of RG 1.59, Rev. 2 Warning time will be sufficient to reach cold shutdown, if required SSCs needed for cold shutdown will utilize temporary barriers for PMF effects 6/29/2017 8
Incorporated Barriers for Mitigation of LIP Event (License Amendment Request)
LIP remains an issue, anticipated flood levels may exceed doors thresholds, installation of flood panels, ramps, thresholds needed to mitigate event Incorporated barriers Permanent ramps Permanent door thresholds Permanent/temporary flood panels Preventative maintenance 6/29/2017 9
Flood Barriers for Mitigation of LIP Event Flood Panel Storage ESW Pumphouse Ramp Flood Panel & Threshold FLEX Bay Ramp 6/29/2017 10
FLO-2D Computer Program (License Amendment Request)
FLO-2D program employs an unsteady state modeling technique; Change in analytical methodology Utilized in Beyond Design Basis event calculations Complex Flooding Simulation Conservation of mass Water storage Site runoff Timing of rainfall event Validation Vendor Appendix B Program FEMA Maricopa County, Arizona 6/29/2017 11
FLO-2D Computer Program (License Amendment Request)
FLO-2D program employs an unsteady state modeling technique Also known as a transient flow technique Unsteady state modeling is described in ANSI N170-1976 Underlying computational methodology of FLO-2D, the program employs the use of the shallow water equations (also known as Saint Venants Equations).
Numerical solution of these equations are referenced in Section 5.4 of ANSI N170-1976 (Reference 1 of Section 5.4.2.1 is Strelkoffs Numerical Solution of Saint-Venant Equation as published in ASCEs Journal of the Hydraulics Division, Jan. 1970)
One of the key capabilities of the program is the ability to perform storage routing functions Storage routing is referenced in the PNPP USAR in that the USAR credits the topographic storage of six inches of precipitation for LIP domain analyses 6/29/2017 12
Crediting Building Exteriors (Exemption Request)
Anticipated flood levels to exceed nuclear island Calculations to evaluate forces to building structures Water height Flow velocity Building construction standards (safety and non safety)
Concrete - ACI 318 or ACI 349 Steel - AISC 7th Edition Periodic maintenance inspections to maintain building conditions Utilize existing Maintenance Rule walkdowns Update to include flood protection criteria Calculations for crediting structures will be established for critical characteristics for periodic inspections 6/29/2017 13
Credit Plant Storm System (Exemption Request)
Storm Sewers Minimizes water surface elevation during LIP Reduces duration of LIP event Corrugated metal with paved invert AASHTO M190 Bituminous Coated AASHTO M218 Galvanized Cleaned and inspected in 2016 Included in FLO-2D model Roof drains Conservatively included in FLO-2D model Roof drains would result in roof storage if inoperable Periodic maintenance inspections to maintain conditions Critical characteristics for periodic inspections will be identified 6/29/2017 14
Credit Plant Storm Drain System 6/29/2017 15
Requested Licensing Action Next Step:
Submittal planned for December 2017 Nominal 12 month review requested Items required for Design Basis LIP analyses and mitigation in proposed licensing action scope:
Technical Specification for time-based warning protection Incorporated barriers for mitigation of LIP event FLO-2D computer program Credit all building exteriors as flood boundaries Credit plant storm drain system 6/29/2017 16