ML102581096

Containment Investigation and Repair

ML102581096
Person / Time
Site:	Crystal River
Issue date:	09/02/2010
From:	Progress Energy Florida
To:	NRC/RGN-II
References
Download: ML102581096 (19)

Text

Crystal River Unit #3 Containment Investigation and Repair September 2, 2010

2 Fission Product Barriers Simplified Schematic Liner Concrete Tendons (horizontals depicted)

Barrier # 1-Cladding Enclosing The Fuel Barrier # 2 - Reactor Vessel & Coolant Piping Barrier # 3 - Containment Liner Tendon depiction is for illustrative purposes and is not an exact scale

3 Steam Generator Replacement Opening Identification of Issue 3

SGR Opening Dimensions

@ Liner 23 6 x 24 9

@ Concrete Opening 25 0 x 27 0

4

• Comprehensive Team Commissioned

• Progress Energy personnel - expertise across fleet

• Industry peers:

• Exelon

• Southern Company

• SCE&G

• External expertise:

• Performance Improvement International (PII)

• MPR Associates

• AREVA

• Worley Parsons

• Wiss, Janney, Elstner Associates (WJE)

• Construction Technology Laboratories (CTL)

Root Cause Analysis Investigation & Design Basis Team

5

• Material Laboratories Support

• MacTec

• Soil & Materials Engineers (S&ME)

• Field Data Support

• Sensing Systems, Inc

• Core Visual Inspection Services (Core VIS)

• Nuclear Inspection & Consulting, Inc

• Precision Surveillance

• Gulf West Surveying, Inc

• AREVA Root Cause Analysis Investigation & Design Basis Team (continued) 5

6

• Numerous PhDs (11) with expertise in:

• Root Cause Investigation Techniques

• Nuclear Engineering

• Nuclear Operations & Maintenance

• Material Science & Testing

• Concrete Standards & Construction

• Concrete Testing

• Concrete Creep

• Concrete Fracture

• Human Performance

• Process Analysis

• Containment Analysis

• Computer Modeling Root Cause Analysis Investigation & Design Basis Team (continued)

7

• Worley Parsons

• 1976 dome delamination investigation and repair (as Gilbert Commonwealth)

• Structural Preservation Systems (SPS)

• Largest Concrete Repair Contractor in the US, 2nd largest Concrete Contractor (of any type) in the US

• Performs > 4,000 repair projects per year

• Wiss, Janney, Elstner Associates, Inc (WJE)

• Structural engineering and materials science firm specializing in failure investigations and problem solving

• Specialist in structural condition assessments and design of repairs and retro-fits for reinforced and post tension concrete structures

• Conducted original CR3 Structural Integrity Test (SIT)

Concrete Operational Experience (OE) 7

8 Nuclear Safety Oversight Committee (NSOC)

Containment Sub-Committee Membership Member Title John Elnitsky (PGN)

VP - New Generation Programs and Projects (Chairman)

Joe Donahue (PGN)

VP - Nuclear Oversight Chris Burton (PGN)

VP - Harris Greg Selby Technical Director - EPRI Dr. Shawn Hughes VP - Shaw Stone & Webster Dr. Paul Zia Civil Engineering Professor, NCSU Hub Miller 33 years industry oversight experience Darrell Eisenhut 41 years industry operation and oversight experience 8

9 Complex Investigation with 75 Potential Failure Modes Considered

• Non-Destructive Testing (NDT) of Containment Wall Surfaces

• Use of Impulse Response (IR) Method and Ground Penetrating Radar (GPR)

• Over 8,000 IR data points taken

• Comprehensive on all accessible areas

• Concrete Core Bores

• Over 150 core bores performed

• Ranged from 1 to 8 diameter, 6 to 32 long

• Validated Impulse Response (IR) data, along with boroscopic inspections

• Laboratory testing Root Cause Analysis Investigation Approach 9

10 Core Borings Conclusion - Physical observation of core boring has validated the delamination boundary, as accurately predicted by Impulse Response (IR).

11

• Concrete Core Laboratory Analyses

• Petrographic Examination

• Modulus of Elasticity and Poissons Ratio

• Density, Absorption, and Voids

• Compressive Strength, Splitting Tensile Strength, and Direct Tensile Strength

• Fracture Energy

• Accelerated Creep Test

• Accelerated Alkali Silica Reaction (ASR) Test

• Chemistry and Contamination Test

• Scanning Electron Microscope (SEM) Examination of Micro-Cracking Root Cause Analysis Laboratory Analysis

12

• Existing Industry Analysis Techniques Predicted Acceptable Margin to Delamination at CR3

• Investigation Required Development of New FEA Tools of Progressively Increasing Complexity based on Data Obtained from the Delamination

• 360o global containment model

• Visco-elastic / non-linear model

• Model includes individual tendons, rebar, liner, etc.

• Sub-models (1 mesh) provide higher resolution of localized behavior Root Cause Analysis Finite Element Analysis (FEA) Modeling Tools

13

• Conclusions

• Design is Acceptable for Normal and Emergency Operations

• Construction was in Accordance with Design

• Delamination Occurred During the Outage

• Investigation was Thorough and Comprehensive

• New State-of-the-Art Analytical Methods had to be Created to Analyze Containment Response

• Root cause: De-tensioning scope and sequence resulted in redistribution of stresses that exceeded tensile capacity

• Could not have been predicted based on existing information and models at that time Root Cause Analysis Summary

14

• Containment Design Features Remain Unchanged

• Prestressed concrete cylindrical wall (shell), shallow dome roof

• Carbon steel liner serves as fission product barrier

• Liner anchored to concrete

• Containment Design Basis Maintained

• Leak-tight structure to contain Design Basis LOCA

• Elastic response to design basis loading to protect liner

• Design loads and combinations based on operating, accident and applicable code requirements

• Load factors applied to provide safety margin Design Basis & Repair FSAR Structural Design Parameters

15

• All Containment Design Loads Analyzed

• Live, Prestress, Dead Loads

• Wind

• Tornado Wind

• Tornado Pressure

• Tornado Missiles

• Seismic

• Temperature Loads

• Accident Pressure (LOCA)

• Accidental Containment Spray Actuation Pressure Design Basis Repair FSAR Design Loads

16

• Final repair condition expected to be acceptable under 10 CFR 50.59

• Design basis loading conditions will be satisfied

• Design code requirements will be met

• Changes to analysis inputs accepted by 50.59 evaluation

• Analysis consistent with the existing FSAR described Method of Evaluation Design Basis & Repair Summary

17 17

• Stress Relief Cut - Complete

• De-tensioning - Complete

• Concrete Removal - Complete

• Concrete Placement - In Progress

• Re-tensioning

• Post-Repair Testing

• Unit Restart Design Basis & Repair Repair Sequence

18

• Integrated Leak Rate Test (ILRT) required per ASME XI code

• For removing / replacing liner in SGR opening

• Plan to perform a Structural Integrity Test (SIT)

• Normally a one-time initial construction structural test

• Test intent: measures structural integrity and deformation at 1.15 Peak Design Pressure (63.3 psig)

• SIT will be followed by ILRT Post Repair Testing Pressure Tests

19 Summary 19 Containment original design and construction are acceptable for normal and emergency operations Planned repair approach meets design basis requirements and code requirements The final repair condition is expected to be acceptable under 10 CFR 50.59 Containment will be fully capable of meeting its design safety function upon completion of repairs and testing