ML18318A064

San Onofre Nuclear Generating Station; Public Meeting Slides with Extra Content

ML18318A064
Person / Time
Site:	San Onofre
Issue date:	11/08/2018
From:	NRC Region 4
To:
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Download: ML18318A064 (39)

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San OnofreSpecial Inspection WebinarNovember 8, 2018NRC Region IV, Arlington, TX Logistics*Webinar Format

• Back-up Bridge Line(888) 469-1677, Passcode 2471451

• Questions and Answers 2

NRC Staff*Eric Simpson, Special Inspection Team LeaderRegion IV Fuel Cycle and Decommissioning Branch

• Patricia Silva, Branch ChiefDivision of Spent Fuel Management

• Troy Pruett, DirectorRegion IV Division of Nuclear Materials Safety 3

Webinar Agenda

• Background

• Canister Downloading Operations

• Inspection Team Findings

• Current Status

• Summary*Questions & Answers 4

ISFSI Layout 5TN NUHOMSDesignHoltecUMAXDesign TransnuclearNUHOMS 6 Holtec UMAX 7

Vertically Ventilated Module (Vault) 8 Spent Fuel Canister 9Holtec MPCTransfer Cask Downloading: Shield Cone 10 Downloading: Transporter 11 Downloading: Vault Door 12 Downloading: Alignment 13 Downloading: Attaching Slings 14 Downloading: Attaching Slings 15 Downloading Preparations 16 17What Happened on August 3rd?Low Dose AreaLow Dose Area What Happened on August 3 rd?18 What Happened on August 3 rd?19 What Happened on August 3rd?

20 21What Happened on August 3 rd?

Post Event Actions

• Spent Fuel Handling Activities Suspended

• NRC Inspection Activities

• San Onofre Notification to NRC

• Causal Evaluations

• Corrective Actions 22 Spent Fuel Handling Activities Suspended 23*MPC 29 lowered into vault

• San Onofre suspends fuel loading

• MPC 30 -Inside Transfer Cask

-Seismically Restrained in Fuel Building NRC Inspection Activities 24*August 6 th: NRC Region IV informally notified of Misalignment Event and initiates daily oversight communications

• August 7 th: San Onofrecommits to NRC review before resuming operations

• August 17 th: NRC decides to conduct Special Inspection

• September 10

-14: NRC Special Inspection Team onsite

• NRC to perform inspection prior to resumption of fuel loading NRC Inspection Activities 25*2 Preliminary Escalated Findings

-Failure to provide redundant drop protection

-Failure to report

• 3 Preliminary Severity Level IV Violations

-Procedures

-Corrective actions

-Training*Management Oversight Weaknesses Causal Evaluations 26*San OnofreApparent Cause Evaluation

• Holtec Root Cause Analysis

• Common Cause Evaluation Root Causes

• San OnofreManagement failed to provide-Adequate procedures

-Adequate training to support procedure-Adequate oversight 27 Corrective Actions

• Training Requirements

• Procedure Enhancements

• Equipment Enhancements

• Oversight Improvements 28 Event Significance

• No Actual Drop of Canister*No Radiological Release

• Load Drop Analysis (if canister fell) 29 Next Steps

• Issue NRC Inspection Report

• NRC Inspection of Causal Analyses

• NRC Inspection of Corrective Actions 30 Summary*Could have been prevented

• Weaknesses in management oversight

• Multiple failed barriers

• Increased NRC oversight 31 Questions 32 Shims 33 ShimsDesign Change: Standoffs PinsOriginal Design:

Machined Slots 34 35Radiation Levels on the ISFSI PadTS limit on Lid = 0.4 mR/hrTS limit on Outlet Vent = 1.8 mR/hrCanister #29 levels in GammaLid: 0.015 mR/hrOutlet Vent: 0.12 mR/hrLids: 0.015

-0.018 mR/hrOutlet Vents: 0.12

-0.24 mR/hrSurvey Results found by the NRC:Closure Lid Aging Management Plan

• Required upon license renewal

• Tracks Degradation of Structures, Systems, and Components

-Concrete-Steel-Stainless Steel

• Some licensees have performed Aging Management Inspections

-No breaches of the canisters have been identified

-No chloride induced stress corrosion cracking has been identified

• California Costal Commission Commitment 36 Canister Drop analysis*San Onofreprovided preliminary analysis

• Analysis under NRC review

• San Onofrepreliminary results: no loss of containment 37 Unresolved Item

• Last NRC Inspection report (2017

-001) documented an Unresolved Item

• Licensee has modified loading operations to address NRC concern 38 Seismic and Flooding

• Both ISFSI systems at San Onofreare evaluated for:

-Design Base Earthquake

-Maximum flood height and flood velocity (Tsunami) 39