ML21047A152

Slides - Perry Pre-Application Flooding 2/16/2021 Meeting Slides (L-2021-LRM-10016)

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

NRC Pre-Submittal Meeting Proposed Request for Licensing Action Perry Flood Hazards February 16, 2021

Presentation Agenda

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 All Information Presented Herein is Information Only For Discussion Purposes Only, Non-Disclosable Information 2

Energy Harbor Representatives 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 All Information Presented Herein is Information Only Confidential, Subject to Confidentiality Agreements For Discussion Purposes Only, Non-Disclosable Information 3

History March 12, 2012; NRC April 11, 2013; Prompt March 10, 2015; Rev. 0 November 3, 2015; New March 24, 2016; Rev. 1 Issues 50.54(f) letter Functionality Assessment Flood Hazard Re- Diversion Channel and Flood Hazard Re-Condition Report 2013- evaluation Report (FHRR) Stream Modifications, evaluation Report 05625, Submitted Field Implemented Submitted Updated by CR 2015-05079 and 2015-08036 July 25, 2016; NRC July 25, 2017; Submittal to April 25, 2018 December 7, 2018 February 19,2019 Interim Staff Response - NRC of Mitigating Notification of Permanent PNPP Submitted Request RAIs received from NRC Flood Hazard Re- Strategies Assessment Cessation of Power on deferral request to defer remaining flooding evaluation Report Audit Operations, PNPP Summary Document Flooding Project actions Suspended March 20,2019 May 6,2019 July 26,2019 November 18, 2019 May 7, 2020 RAI Responses provided Deferral Request Accepted Cessation Letter Perry Flooding Focused 50.54(f) Letter Actions with two commitments Withdrawn Evaluation Submitted Closed (Based on planned Flooding Project Restarted actions described in FE)

All Information Presented Herein is Information Only Confidential, Subject to Confidentiality Agreements For Discussion Purposes Only, Non-Disclosable Information 4

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 PMF streamflow stay within streams drainage basins Local Intense Precipitation (LIP)

Reevaluation of LIP shows the LIP event is controlling All Information Presented Herein is Information Only Confidential, Subject to Confidentiality Agreements For Discussion Purposes Only, Non-Disclosable Information 5

Proposed Request for Licensing Action Scope 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)

All Information Presented Herein is Information Only Confidential, Subject to Confidentiality Agreements For Discussion Purposes Only, Non-Disclosable Information 6

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 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 All Information Presented Herein is Information Only Confidential, Subject to Confidentiality Agreements For Discussion Purposes Only, Non-Disclosable Information 7

Incorporated Barriers for Mitigation of LIP Event (License Amendment Request)

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 All Information Presented Herein is Information Only Confidential, Subject to Confidentiality Agreements For Discussion Purposes Only, Non-Disclosable Information 8

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 9

Flooding Methodology Changes (License Amendment Request)

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 All Information Presented Herein is Information Only Confidential, Subject to Confidentiality Agreements For Discussion Purposes Only, Non-Disclosable Information 10

FLO-2D PRO 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 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)

All Information Presented Herein is Information Only Confidential, Subject to Confidentiality Agreements For Discussion Purposes Only, Non-Disclosable Information 11

Credit Plant Storm System (Exemption Request)

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 All Information Presented Herein is Information Only Confidential, Subject to Confidentiality Agreements For Discussion Purposes Only, Non-Disclosable Information 12

Credit Plant Storm Drain System All Information Presented Herein is Information Only Confidential, Subject to Confidentiality Agreements For Discussion Purposes Only, Non-Disclosable Information 13

Requested Licensing Action 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)

All Information Presented Herein is Information Only Confidential, Subject to Confidentiality Agreements For Discussion Purposes Only, Non-Disclosable Information 14

QUESTIONS?

All Information Presented Herein is Information Only Confidential, Subject to Confidentiality Agreements For Discussion Purposes Only, Non-Disclosable Information 15