ML21047A152
| ML21047A152 | |
| Person / Time | |
|---|---|
| Site: | Perry  |
| Issue date: | 02/16/2021 |
| From: | Energy Harbor Nuclear Corp |
| To: | Division of Operating Reactor Licensing |
| Buckberg P | |
| References | |
| L-2021-LRM-10016 | |
| Download: ML21047A152 (15) | |
Text
February 16, 2021 NRC Pre-Submittal Meeting Proposed Request for Licensing Action Perry Flood Hazards
Confidential, Subject to Confidentiality Agreements For Discussion Purposes Only, Non-Disclosable Information Presentation Agenda 2
All Information Presented Herein is Information Only
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
Confidential, Subject to Confidentiality Agreements For Discussion Purposes Only, Non-Disclosable Information Energy Harbor Representatives 3
All Information Presented Herein is Information Only Stan Gorski, Manager - Strategic Engineering Dan Lieb, Acting Manager - Design Engineering Phil Lashley, Manager - Fleet Licensing Mark Mlachak, Manager - Fleet Oversight Jeremy Schudel, Supervisor - Design Engineering Kathy Nevins, Fleet Licensing Mark Bensi, Design Engineering
Confidential, Subject to Confidentiality Agreements For Discussion Purposes Only, Non-Disclosable Information History 4
All Information Presented Herein is Information Only 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 April 25, 2018 Notification of Permanent Cessation of Power Operations, PNPP Flooding Project Suspended December 7, 2018 PNPP Submitted Request to defer remaining flooding actions February 19,2019 RAIs received from NRC on deferral request March 20,2019 RAI Responses provided with two commitments May 6,2019 Deferral Request Accepted July 26,2019 Cessation Letter Withdrawn Flooding Project Restarted November 18, 2019 Perry Flooding Focused Evaluation Submitted May 7, 2020 50.54(f) Letter Actions Closed (Based on planned actions described in FE)
Confidential, Subject to Confidentiality Agreements For Discussion Purposes Only, Non-Disclosable Information Flood Hazards 5
All Information Presented Herein is Information Only 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 PMF streamflow stay within streams drainage basins Local Intense Precipitation (LIP)
Reevaluation of LIP shows the LIP event is controlling
Confidential, Subject to Confidentiality Agreements For Discussion Purposes Only, Non-Disclosable Information Proposed Request for Licensing Action Scope 6
All Information Presented Herein is Information Only All hazards except for LIP have been passively mitigated.
Site drainage (LIP Domain) remains the controlling site flood hazard based on reconstituted analyses using FLO-2D Pro computer program Items required for Design Basis LIP analyses and mitigation in proposed licensing action scope:
Flooding methodology changes (Amendment)
Time-based warning based on meteorological forecasting (Amendment)
Incorporated barriers (deployable and permanent) for mitigation of LIP event (Amendment)
Credit non-safety incorporated barriers to mitigate GDC-2 hazard (Exemption)
Credit non-safety plant storm system to mitigate GDC-2 hazard (Exemption)
Confidential, Subject to Confidentiality Agreements For Discussion Purposes Only, Non-Disclosable Information Time-Based Warning Protection (License Amendment Request) 7 All Information Presented Herein is Information Only 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 developed using process consistent with LIP PMF (FLO-2D Pro)
Hardened Protection also provided for other non-LIP events such as Cool-Season PMP and non-precipitation events such as exterior tank failure and ESW Swale discharge PNPP Operational Requirements Manual (ORM) will contain requirement for temporary barrier deployment in response to meteorological warning
Proposed in lieu of plant Technical Specifications as discussed RGs 1.59 and 1.102
ORM will only require plant shutdown if barriers are not deployed within specification timeframe. Anticipatory shutdown not proposed.
Proceduralized response for events in excess of SPS/SPF
Advanced warning to be received from external meteorological firm
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
Confidential, Subject to Confidentiality Agreements For Discussion Purposes Only, Non-Disclosable Information Incorporated Barriers for Mitigation of LIP Event (License Amendment Request) 8 All Information Presented Herein is Information Only In order to mitigate the reconstituted flood hazards at building exteriors, PNPP proposes use of incorporated barriers as defined in RG 1.102.
Barriers will be either permanent or temporary, depending on the location of interest.
Permanent Incorporated barriers Concrete flood walls Aluminum flood walls Ramps Closure Plates Deployable Incorporated Barriers Aluminum stop log design with steel end channels Integrated seals, very low leakage allowance Certified to ANSI/FM-2510 No tools required for deployment Designed for all loads including flood-borne missile impacts
Confidential, Subject to Confidentiality Agreements For Discussion Purposes Only, Non-Disclosable Information 9
Incorporated Barriers (License Amendment and Exemption Request)
All Information Presented Herein is Information Only
Confidential, Subject to Confidentiality Agreements For Discussion Purposes Only, Non-Disclosable Information Flooding Methodology Changes (License Amendment Request) 10 All Information Presented Herein is Information Only FLO-2D Pro Software Used to Perform Complex Flooding Simulation (precipitation and non-precipitation event)
Conservation of mass
Water storage
Site runoff
Timing of rainfall event
Storm Drain System analysis Diversion Stream berm inflow routing
Breach profile determined using USACE guidance (RD-5 and RD-13)
Incorporated as a steady-state inflow with flood-routing performed by FLO-2D FLO-2D Pro Validation Vendor Appendix B Program FEMA Maricopa County, Arizona Flood-borne Missile Evaluations Method obtained from FEMA P-259, supplemented by ASCE 7-10 and ANSI A58.1-1972
Confidential, Subject to Confidentiality Agreements For Discussion Purposes Only, Non-Disclosable Information 11 All Information Presented Herein is Information Only 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 EPAs SWMM Module
Runs as a sub-routine within FLO-2D Pro
Models subsurface flow under gravity and pressurized flow conditions
Exchanges volume with surface model (FLO-2D)
FLO-2D PRO Computer Program (License Amendment Request)
Confidential, Subject to Confidentiality Agreements For Discussion Purposes Only, Non-Disclosable Information Credit Plant Storm System (Exemption Request) 12 All Information Presented Herein is Information Only Storm Drain System 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
Confidential, Subject to Confidentiality Agreements For Discussion Purposes Only, Non-Disclosable Information Credit Plant Storm Drain System 13 All Information Presented Herein is Information Only
Confidential, Subject to Confidentiality Agreements For Discussion Purposes Only, Non-Disclosable Information Requested Licensing Action 14 All Information Presented Herein is Information Only Next Step:
Submittal planned for March 2021 Nominal 12-month review requested Items required for Design Basis LIP analyses and mitigation in proposed licensing action scope:
Flooding methodology changes (Amendment)
Time-based warning based on meteorological forecasting (Amendment)
Incorporated barriers (deployable and permanent) for mitigation of LIP event (Amendment)
Credit non-safety incorporated barriers to mitigate GDC-2 hazard (Exemption)
Credit non-safety plant storm system to mitigate GDC-2 hazard (Exemption)
Confidential, Subject to Confidentiality Agreements For Discussion Purposes Only, Non-Disclosable Information 15 All Information Presented Herein is Information Only QUESTIONS?