Workshop on Nuclear Plant Life Workshop on Nuclear Plant Life Extension Research and Development Tom Esselman l Principal, Lucius Pitkin, Inc. February 22, 2011 Lucius Pitkin, Inc. , Consulting Engineers 1
Prepare a Containment Inspection Guide to support operation beyond 60 years support operation beyond 60 years. Obtain information on containment integrity from the Ginna and Nine Mile Point plants from the Ginna and Nine Mile Point plants. 2
Program activities are selected to: ◦ Demonstrate a linkage between a l k b degradation mechanism that may occur and inspections or tests that are to be performed inspections or tests that are to be performed. ◦ Provide inspections and tests that are quantifiably reproducible over a 40 year quantifiably reproducible over a 40 year period. 3
The scope includes concrete and other materials associated with a containment function. ◦ Concrete containment structures including C t t i t t t i l di reinforced, pre-stressed, and post-stressed systems. ◦ Tendons including wires, anchorages, shims, etc. ◦ Drywell/torus/suppression pool. ◦ Basements and foundations of the containment. ◦ Concrete structures inside the containment. ◦ Structural members housed within the concrete (RCS supports, embedments, etc.). ◦ Containment liner, penetrations, and attachments. 4
Degradation Augmented Tests Or Stressor Effect Mechanisms Inspections At Ginna Measure strain near Chronic Intermediate p penetration. Local Loss Of Local Loss Of Reduced Elastic Modulus Reduced Elastic Modulus T Temperature Exposure t E Moisture and Rupture Strength Measure concrete (>200 F) temperature at time of DIC. Effects Cement Paste By Gamma Radiation (>10 19 Radiolysis Of Water. None proposed. Rads) Reduction In Strength. Reduction In Strength Radiation Damage Radiation Damage Neutron Radiation (>10 19 Swelling of Aggregates. None proposed. N/Cm 2 ) Reduction In Strength. No augmented testing Diminished Strength Of proposed. Exposure To Water Exposure To Water Cement Paste And Cement Paste And Latest inspection did not Leaching Of Calcium Through Cracks Reduced Concrete show any active areas of Hydroxide (Seen As (Depends On Strength. Lowered pH leaching or efflorescence. Efflorescence) Temperature And And Subsequent If detected in the future, Chemistry) Breakdown Of Protective samples could be collected p Film On Rebar. Film On Rebar and tested. Magnesium And Sulfates Swelling Causing Cracking Of Potassium, Sodium, And Spalling, Leading To None Proposed. And Magnesium. Reduced Strength. Chemical Attack Increased Porosity And Increased Porosity And Acids permeability, Reduced None Proposed. Alkalinity 5
Degradation Augmented Tests Or Stressor Effect Mechanisms Inspections At Ginna Some Constituents Of Aggregate Are gg g No augmented testing Reactable In The proposed. Presence Of Moisture, Alkali-Aggregate With Chemical Expansive Stresses And This is effectively covered Reaction Compounds Present In Severe Cracking by visual examination of Cement, Mostly Alkalis , y outside surface in the outside surface in the But Also Includes existing IWL/IWE exams. Potassium, Sodium, And Calcium Oxides. Carbon Dioxide From Air Reacts With Calcium Hydroxide In Cement In Reduced pH, Rebar Carbonation test on Carbonation The Presence Of Corrosion containment exterior wall. Moisture Producing Calcium Carbonate No augmented testing No augmented testing Heavy Load Traffic proposed. Exposure To Strong This is effectively covered Pitting, Loss Of Cement Abrasion Wind by visual examination of And Aggregate Exposure the outside surface of the Exposure To Turbulent Containment in existing C t i t i i ti flow And Cavitation IWL. 6
Degradation Augmented Tests Or Stressor Effect Mechanisms Inspections At Ginna High Loading Such As Cracking Along Monitor tendon loads by Under Tendon Anchors, Cement/Aggregate gg g Creep (Mostly In Creep (Mostly In strain gages. High Temperature Such Boundary And Continued Prestressed As Near Penetrations, Strain Under Constant Measure strain at Concrete) Changes Of Moisture In Load Causing Loss Of penetration. Concrete Prestress. Concrete Cracking And g Creep Measure strain of concrete Tendon Relaxation during SIT. Cyclic Loading, Including Fatigue Loads From ILRT Loss of Bond With Rebar Monitor strain gage on rebar and concrete. Surface Spalling And Surface Spalling And Internal Cracking Measure strain of concrete Applied Load Severe Cracking during SIT at high stress locations. Overstress Overstress Loss of Prestress Loss of Prestress High Rebar Loads High Rebar Loads Monitor strain gage on Settlement Wire Relaxation rebar and concrete. Moisture Environment Cracking And Loss Of MIC MIC Such As Below Grade Such As Below Grade None Proposed None Proposed. C Cement. Exterior Walls 7
Tendon load monitoring with fiber optic strain gages. Rebar strain gage monitoring. Concrete surface strain monitoring with C f i i i i h Digital Image Correlation. Rebar corrosion protection monitoring with Rebar corrosion protection monitoring with carbonation test. 8
Fiber optic strain gages will be applied will be applied to the shims of 20 tendons. 20 tendons. 9
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Select one currently exposed rebar and install fiber optic strain gage. Install concrete strain measuring fiber optic gage in close proximity to the rebar strain gage in close proximity to the rebar strain gage. Monitor both with the tendon monitoring Monitor both with the tendon monitoring system. 13
DIC is a non-destructive non-contact technique to measure changes in shape and strain on structure surface. DIC requires that a pattern be painted onto the surface the surface. High-strain locations selected for DIC. Can be used to demonstrate that concrete Can be used to demonstrate that concrete shape is not changing due to swelling or other degradation and that strain is g appropriate during SITs. 14
Concrete Beam DIC Camera 15 and Lights
Carbonation is a chemical reaction of Portland cement with the atmosphere that causes reduction in concrete pH. d ti i t H Reduction in concrete pH makes rebar more susceptible to corrosion attack susceptible to corrosion attack Tests are performed on external surface concrete with holes drilled into the concrete. If depth of carbonation penetration is less than rebar cover, corrosion protection is adequate. 16
An improved understanding of behavior and the results from the behavior and the results from the Ginna and NMP inspections will lead into the preparation of the into the preparation of the Containment Inspection Guide. The guide will provide a methodology The guide will provide a methodology for baseline inspections and examinations and follow-up examinations and follow up inspections for long term operation. 17
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