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
6/29/2017 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 2
6/29/2017 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 3
6/29/2017 History 4
March 12, 2012; NRC Issues 50.54(f) letter April 11, 2013; Prompt Functionality Assessment Condition Report 2013-05625, Updated by CR 2015-05079 and 2015-08036 March 10, 2015; Rev. 0 Flood Hazard Re-evaluation Report (FHRR) Submitted November 3, 2015; New Diversion Channel and Stream Modifications, Field Implemented March 24, 2016; Rev. 1 Flood Hazard Re-evaluation Report Submitted July 25, 2016; NRC Interim Staff Response -Flood Hazard Re-evaluation Report Audit July 25, 2017; Submittal to NRC of Mitigating Strategies Assessment Summary Document
6/29/2017 5
6/29/2017 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
6/29/2017 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 7
6/29/2017 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 8
6/29/2017 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 9
6/29/2017 Flood Barriers for Mitigation of LIP Event Flood Panel & Threshold FLEX Bay Ramp ESW Pumphouse Ramp 10 Flood Panel Storage
6/29/2017 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 11
6/29/2017 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 12
6/29/2017 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)
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 13
6/29/2017 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 14
6/29/2017 Credit Plant Storm Drain System 15
6/29/2017 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 16