Coal Combustion Facility Assessment Report. October 20, 2010

Transcription

1 Coal Combustion Facility Assessment Report October 20, 2010

2 Introduction Stantec Consulting Services Inc. North American Consulting Firm 10,000 Engineers, Geologists, Architects, Scientists and Technicians 140 Geotechnical Engineers Clients include: USACE FEMA Power Generating Industry John S. Montgomery, PE Senior Principal Licensed Professional Engineer in Tennessee, Kentucky and Alabama Over 23 Years Experience Dam and CCP Disposal Design and Construction 1

3 Presentation Outline Program Overview Phase 1 Facility Review Phase 2 Engineering Assessment Phase 3 Remediation Design and Construction Phase 4 Programmatic Improvements 2

4 Presentation Outline Program Goals Assess Structural Conditions of Impoundments Implement Improvements Program Statistics FY10 Man-hours ~ 472,324 FY 09 Engineering g Man-hours ~ 168,074 Borings ~781 (47,000 ft of footage drilled) Instruments ~ 594 Rock Placed ~ 455,305 tons Sand ~ 26,277 tons Phases 1,2,3 and 4 in Parallel Construction of Improvements at Bull Run 3

5 Program Overview Phase 1 Facility Review COMPLETE Records Review/Staff Interviews Site Condition Review Recommendations for Future Analysis, Studies, and Program Improvements Final Report Issued June 24, 2009 Phase 2 Engineering Assessments COMPLETE Geotechnical Explorations Hydrologic and Hydraulic Analysis Dam Safety Hazard Classifications Spillway Inventories 4

6 Program Overview Phase 3 Remediation Design and Construction Structural Deficiencies Improve Freeboard (Storage) Risk Reduction Phase 4 Programmatic Improvements COMPLETE Dam Safety Inspection Training Programmatic Documents 5

7 Phase 2 Engineering Assessments General Findings Seepage Steep Slopes Slope Stability Occasional Surface Slumps Operational and Storm Freeboard (Storage) Poor Surface Drainage / Standing Water All Issues Are Being Addressed Geotechnical Drilling at Cumberland 6

8 Phase 2 Engineering Assessments Geotechnical Explorations Geotechnical Exploration Statistics 781 Borings 47,000 Linear Feet of Drilling FS=1.4 20,000 Samples Retrieved 17,000 Tests Performed Ash 594 Instruments Installed Slope Stability Findings All Facilities > Met Criteria Aggressively Working to Improve Others Conditions Suggesting Imminent Failure not Observed FS Factor of Safety : Strength Driving Force Minimum Criteria: FS > 1.5 (Long Term, Static) Source US Army Corps of Engineers EM

9 Phase 2 Engineering Assessments Geotechnical Explorations Comparison to Kingston Root Cause Analysis Increased Loads Due to Higher Fill Fill Geometry and Setbacks Unusual Weak Silt/Ash Slime Foundation Hydraulically Placed Loose Wet Ash This Combination of Conditions Was Not Observed at Any Other Facility 8

10 Phase 2 Engineering Assessments Dam Safety Hazard Classification Low Hazard Potential No Probable Loss of Human Life Low Economic/Environmental Losses Losses Principally Limited to Owners Property. Significant Hazard Potential No Probable Loss of Human Life Can Cause: Economic Loss Environmental Damage Disruption of Lifeline Facilities Impacts to Other Concerns High Hazard Potential Probable Loss of Human Life Source: FEMA 333 Issued April

11 Phase 2 Engineering Assessments Dam Safety Hazard Classification - Initial TVA Fossil Plants Allen Bull Run Colbert Cumberland Gallatin John Sevier Johnsonville Kingston Paradise Shawnee Widows Creek Facility Ash Disposal Ash Pond Gypsum Dry Stack Bottom Ash Ash Pond Gypsum Ash Disposal Dry Stack Bottom Ash Ash Disposal Dike C Ash Pond Scrubber Complex Dry Stack Ash Pond Ash Pond Gypsum Initial Hazard Classification N/A N/A N/A Hazard Classification High Significant Low 10 Colbert Bottom Ash Pond Dike Lowering to Remove High Hazard

12 Phase 2 Engineering Assessments Dam Safety Hazard Classification Current TVA Fossil Plants Allen Bull Run Colbert Cumberland Gallatin John Sevier Johnsonville Kingston Paradise Shawnee Widows Creek Facility Ash Disposal Ash Pond Gypsum Dry Stack Bottom Ash Ash Pond Gypsum Ash Disposal Dry Stack Bottom Ash Ash Disposal Dike C Ash Pond Scrubber Complex Dry Stack Ash Pond Ash Pond Gypsum Hazard Classification High Significant Low Current Hazard Classification N/A N/A N/A 11

13 Phase 2 Engineering Assessments Spillway Inventory Spillway Pipe That Discharges Permitted Flows From an Impoundment Tall Unsupported Risers Outlet Pipes Spillway Replacement Johnsonville Colbert Shawnee Widows Creek Cumberland Outlet Pipe Dam Riser Shawnee Spillway Replacement Typical Spillway 12

14 Status 76 Capital Projects Currently in Planning, Design, Construction or Completed Phase TVA Fossil Plant Planning Design Implementation/ Complete Allen Bull Run Colbert Cumberland Gallatin 1-1 John Sevier 2-1 Johnsonville 3-6 Kingston Paradise Shawnee Widows Creek System Wide

15 Status East Ash Pond Allen East Stilling Pond Main Ash Pond Area 2 Bull Run Bottom Ash Disposal Area 1 Gypsum Disposal Area 2A Disposal Area 5 Colbert Ash Pond 4 Dry Ash Stack Cumberland Ash Pond Gypsum Storage Area Fly Ash Pond E Gallatin Bottom Ash Pond A Stilling Pond B, C and D Dry Fly Ash Stack John Sevier Bottom Ash Disposal Area 2 Ash Disposal Area J (Closed) Johnsonville Ash Disposal Area 2 Kingston Paradise Shawnee Widows Creek Dike C Scrubber Sludge Complex Peabody Ash Pond Dry Stack AhP Ash Pond Ash Pond Complex Gypsum Stack Complex Calendar Year Global Stability As Found Current July or 1.5 Greater to Less than Oct

16 Johnsonville Ash Pond ACTION: Spillway Closure ACTION: Spillway Replacement Kentucky Lake ACTION: Lower Pool 2.6 Feet ACTION: Spillway Closure ACTION: Rock Buttress / Seepage Blanket ACTION: Rock and Clay Buttress / Seepage Blanket Improvement Actions

17 Johnsonville Ash Pond South Spillway Inlets - Before South Spillway Inlets - After 16

18 Johnsonville Ash Pond South Spillway Outlets - Before South Spillway Outlets - After 17

19 Johnsonville Ash Pond North East Dike - Before North East Dike - After 18

20 Johnsonville Ash Pond North East Dike - Before North East Dike - After 19

21 Paradise Scrubber Sludge Complex ACTION: Drainage Improvements ACTION: Trees Removed and Vegetation Cut to Facilitate Frequent Slope Inspections. ACTION: Relocate Operating Pool Spring, 2011 Scrubber Sludge Complex East Pond ACTION: Fill and Regrade Pond ACTION: Rock Buttress /Slope Armoring / Seepage Blanket Spillways West Pond Stilling Pond ACTION: Grout Abandoned Pipes Improvement Actions

22 Paradise Scrubber Sludge Complex East Pond South Slope Buttress - Before East Pond South Slope Buttress - After 21

23 Paradise Scrubber Sludge Complex East Pond East Slope Armoring - Before East Pond East Slope Armoring - After 22

24 Bull Run Ash Pond and Gypsum Stack ACTION: Ditch Grading ACTION: East, West and North Slope Grading East and West Dredge Cells Bottom Ash Disposal Area 1 Gypsum Disposal Area 2A ACTION: French Drain ACTION: Lower Pool in Ash pond to Elev. 801 ACTION: West and South Slope Grading Fly Ash Pond Area 2 ACTION: Slope Armoring ACTION: Rock Buttress / Armoring Stilling Pond Area 2 Improvement Actions

25 Bull Run Gypsum Stack Gypsum Stack Buttress - After Gypsum Stack Buttress - Before 24

26 Bull Run Gypsum Stack Gypsum Stack Buttress After Pool Lowering Ash Pond Pool Before Pool Lowering 25

27 Bull Run Gypsum Stack Slope and Drainage Improvements Slope and Drainage Improvements 26

28 Widows Creek Gypsum Stack and Ash Pond ACTION: Rock Toe Buttress Around Perimeter of Main Ash Pond ACTION: Surface Water Drainage System with Seepage Control around Gypsum ACTION: Main Ash Pond Dredging and Spillway Replacements with Lowered Normal Pool Red Water Pond Main Ash Pond A ACTION: Grouted Abandoned Spillway Pipes ACTION: Constructed Buttress on West Slope of Gypsum Stack ACTION: Seepage Control Bottom Ash Stack Gypsum Stack Abandoned Ash Disposal Area Stilling Ponds Old Scrubber Sludge Pond Dredge Cell Gypsum Stack Stilling Pond ACTION: Dredge Cell Closure Construction with Crowned Cap Pump Pond Tennessee River Improvement Actions ACTION: Seepage control along North/South Perimeter of Dredge Cell

29 Widows Creek Gypsum Stack Gypsum Stack West Slope Buttress - Before Gypsum Stack West Slope Buttress - After

30 Widows Creek Gypsum Stack Gypsum Stack Seepage Drain and Armoring Gypsum Stack Seepage Drain and Armoring 29

31 Cumberland Ash Pond and Gypsum Stack ACTION: Lower Ash Pond Pool Cumberland River Ash Pond ACTION: Spillway Modifications ACTION: Permanent Pool Eliminated from Gypsum Stack, March 2009 Dry Ash Stack ACTION: Regrade Slopes and Perimeter Ditch, Buttressing Gypsum Disposal Area ACTION: Rock Toe Buttress Improvement Actions

32 John Sevier Ash Complex ACTION: Construct Toe Drain at Lower Perimeter Road ACTION: Grout Abandoned Spillway Pipes ACTION: Regrade / Flatten Slope ACTION: Regrade Slope between Upper and Lower Perimeter Roads Dry Ash Stack ACTION: Placement of Riprap Shoreline Protection for Scour Mitigation Sediment Pond East Ash Disposal Area J Sediment Pond West ACTION: Armor Interior Slopes to Eliminate Wave Erosion and Animal Burrows ACTION: Reshaped Slope near Spillway Outlets Stilling Pond Area 2 Bottom Ash Disposal Area 2 Improvement Actions

33 Phase 4 Programmatic Improvements Dam Safety Inspection Training Training Sessions at Each Fossil Plant Two Sessions in Chattanooga Over 300 Staff Received Training Training Elements Included: Roles and Responsibilities Failure Modes Case Histories Specific Plant CCP Features Design Philosophy Inspection Program Dam Safety Training Coal Combustion Product Management Unit Impoundments Tennessee Valley Authority Prepared for Gallatin Fossil Plant (GAF) Personnel Inspection Program August 26,

34 Phase 4 Programmatic Improvements Programmatic Documents Volume 1 Program Management and Responsibilities Volume 2 Facilities Design and Construction Requirements Volume 3 Operation, Maintenance, and Inspection 33

35 Coal Combustion Facility Assessment Report Thank You

36 Status Material Totals For FY10 (excluding KIF) Man-hours ~ 472,324 Rock Placed ~ 455,305 tons Sand ~ 26,277 tons Instrumentation at Gallatin Paradise Scrubber Complex Armoring 35