ML042370380

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Meeting Presentation on Decommissioning, and Ltp Update
ML042370380
Person / Time
Site: Haddam Neck File:Connecticut Yankee Atomic Power Co icon.png
Issue date: 08/24/2004
From:
Connecticut Yankee Atomic Power Co
To:
NRC/FSME
Shared Package
ML042370290 List:
References
-RFPFR
Download: ML042370380 (22)
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Text

Decommissioning, and LTP Update Meeting with USNRC August 17, 2004 1

Discussion Topics

  • Decommissioning Update
  • Groundwater Monitoring Results Update
  • Building Characterization Results
  • Status of Biennial LTP Update
  • LTP Amendment Approach

- Conceptual Model

- Dose Calculation Methodology

- Implementation

  • Summary and Schedule 2

Decommissioning Update

  • FSS of 400 Acres - Class 2 and 3 Areas Complete
  • ORISE Inspection of 400 Acres Complete
  • FSS of Landfill Area - Class 1 & 2 Areas Complete
  • 13 of 43 Canisters Located at the ISFSI 8/12
  • Secondary Side Building Removal Begun
  • Complete Tank Farm Soil Removal 11/04
  • Start RCA Building Removals 8/04
  • Complete Fuel Transfer 1/05
  • Complete Physical Decommissioning 12/06
  • Release Non-ISFSI Areas From License Mid-2007 3

Biennial LTP Update

  • LTP Update Issuance expected by the End of August
  • Changes are the same as discussed on 3/9/04
  • No changes have triggered Prior NRC Approval due to the LTP License Conditions or 10CFR 50.59 Criteria 4

Tritium Trend 160,000 NRC Criteria (25 mrem/yr) = 652,000 pCi/L EPA Drinking Water Standard = 20,000 pCi/l 140,000 MW-105S MW-109D 120,000 MW-102D MW-103D Concentration in pCi/L 100,000 80,000 60,000 40,000 20,000 0

Jan-99 Jan-00 Jan-01 Jan-02 Jan-03 Jan-04 Jan-05 5

Strontium-90 Trend 250 NRC Criteria (25 mrem/yr) = 251 pCi/l EPA Drinking Water Standard = 8 pCi/l 105S 200 103S 106S Concentration in pCi/L 150 100 50 0

6/01 12/01 7/02 1/03 8/03 2/04 9/04 6

GW Source Identification X

X X TK-20 X X X X X X X X X TK-62 X

X X X X X X X X X X X RADWASTE FUEL BUILDING REDUCTION FACILITY XX X X X X

X X

X X X

X X REACTOR 115KV PAB CONTAINMENT SWITCHYARD X X X X

X X

X X

X TK TK X 25-1A 25-1B X X X X X

X X

X SWITCHGEAR BLDG. " B" SOIL AFFECTING GROUNDWATER SERVICE SOIL REMOVAL REQUIRED BUT NOT BUILDING AFFECTING GROUNDWATER NO SUBSURFACE REMEDIATION REQUIRED DIESEL BOILER ROOM AUX. BAY TURBINE BUILDING 7

Above/below grade structure removed 6 layer of popcorn concrete Below grade structure remaining REACTOR CONTAINMENT BUILDING Bed Rock El. 121-0 SPENT FUEL BUILDING El. 48-6 El. 48-6 El. 47-0 NEW FUEL STORAGE El. 35-0 SPENT FUEL POOL El. 22-0 El. 21-6 El. 21-6 FUEL RACKS El. 21-6 El. 17-6 El. 17-6 Fuel Transfer Tube El. 13-6 Fuel Transfer Tube El. 1-6 El. 6 El. 6 El. 6 El. 0 El. 6 El. 6 March 10, 2004 Yetter\BNL_SFB00. cdr NOT TO SCALE / FOR PRESENTATION PURPOSES ONLY CONNECTICUTYANKEE ATOMIC POWER COMPANY GENERAL ARRANGEMENTDRAWING 8 POTENTIALLY CONTAMINATED BELOW GROUND CONCRETE

Building/Pipe Characterization

  • Concrete Cores Taken In:

- RHR Pit

- Cable Vault

- Containment Walls and Mat (Also Bedrock Cores)

- In-Core Sump

  • Analyzed for:

- Gamma Radionuclides

- Tritium

- Selected Samples analyzed for

  • Transuranic Radionuclides
  • Other Hard to Detect Radionuclides
  • Containment Sump RHR Suction Line Survey 9

Building Characterization Results

  • RHR Pit of the Primary Auxiliary Building

- Significant Interior Surface Contamination

- H-3 Volumetric Contamination of Pit Wall near to Former RWST Area below 25 mrem/yr DCGLs

- Decision: Remove Entirely

  • Cable Vault

- Low Internal Surface Contamination

- H-3 & Sr-90 Volumetric Contamination of Walls and Floors below 25 mrem/yr DCGLs

- Decision: Remove to 4 foot Below Grade 10

Building Characterization (Cont.)

  • Containment Areas other than In-Core Sump

- Significant Surface Contamination of Internal Floors

- Volumetric Contamination of Concrete outside of the Containment Liner below 25 mrem/yr DCGLs:

  • Primarily H-3, Other Radionuclides well below DCGLs

- Decision: Remove Concrete to Containment Liner

  • Containment In-Core Sump

- One Sample (Area of expected highest activation under Reactor)

- Estimates of Levels of H-3 in Concrete to Remain Significantly Higher then Current Volumetric DCGL

- Decision: Difficult Remediation - Use Basement Fill Model 11

Building Characterization (Cont.)

- Initial Contamination Levels Approximately 1 Million dpm/100cm2

- Pipe Decon conducted using 40,000 psi Hydrolazer

- 9 Full Passes of Embedded Pipe

- Post Decon Survey: No Contamination over

Background

- FSS of pipe to be conducted when exterior soil has been removed in October 2004 time frame 12

LTP Revision 1a Demolition Approach

  • Decontaminate Building to Surface and Volumetric DCGLs
  • Conduct Final Status Survey with Building Standing
  • Buildings Demolished to 3 foot below grade
  • Demolition Debris used to backfill the basement 13

Dose Modeling and Final Status Surveys

  • Land Areas

- Three Dose Pathways Included

  • Soil
  • Existing Groundwater

- Areas Impacted by Aquifer Plume Resident Farmer

- Buildings

  • Groundwater from Buried Debris 25mr / yr DTotal = DSoil + DExisting GW + DGWfromDebris 14

Revised Demolition Approach

  • Containment Basement:

- Remove Internal Concrete to the Containment Liner

- Perform Final Status Survey of Surfaces and Volumetric Contamination to Building Occupancy DCGLs Except for Inaccessible Areas;

  • Piping to be grouted
  • In-core Sump rendered inaccessible with Flowable Fill

- Calculate Future Groundwater Dose with Basement Fill Model

- Backfill Basement w/Clean Fill to Approximately 3 ft below grade (includes a protective membrane covered with 1 foot of fill)

- Dispose of Building above 4 ft below grade, membrane and sacrificial fill above membrane as Rad Material

- Survey Surface of fill remaining at 4 ft below grade

- Backfill to grade with clean fill and conduct Surface and Subsurface Final Status Surveys after Isolation and Controls established 15

Revised Demolition Approach (Cont.)

  • Fuel Building Spent Fuel Pit: Same Approach as Containment except that liner is to be removed
  • Other RCA Building Basements to Remain (such as B Switchgear & Cable Vault with very low contamination history)

- Characterization Results indicate that Decontamination of Basement may not be required

- Membrane and Sacrificial fill layer may not be required due to low contamination history of structure above 4 foot below grade

- Otherwise approach is same as Fuel Building 16

Basement Fill Model

  • Calculates Dose from Future Groundwater
  • Determines Total Activity Inventory Available for Release to Groundwater from:

- Liner and Embedded Piping Inside Surfaces

- Radioactivity Released from Volumetric Contamination Controlled by Diffusion Rate thru Basement Walls and Flowable Fill (Based on Brookhaven Lab Diffusion Study) for:

  • Containment Walls and Floor Mat
  • In-Core Sump (Includes Flowable Fill)
  • Spent Fuel Pit 17

Basement Fill Model (Cont.)

  • Equilibrium Calculated between Backfill Soil and Groundwater for each Basement
  • Assumptions of Basement Fill Model:

- Backfill Material Kd to be determined by Testing of Actual Backfill Soil Samples at Brookhaven Lab

- No Recontamination of Liner Walls

- No Credit for Containment Liner 18

Basement Fill Model (Cont.)

  • Resulting Groundwater Concentration will be compared to the Groundwater DCGL in HNP LTP Revision 1a to determine dose from Future Groundwater
  • For Land Areas which include a Building Basement, Sum of Doses to Show compliance Includes:

- Soil Dose (per HNP LTP Revision 1a)

- Existing Groundwater Dose (per HNP LTP Revision 1a)

- Future Groundwater Dose calculated by Basement Fill Model (Per Proposed License Amendment) 19

Chapters Effected By LTP Amendment

  • Chapter 2 - Summary Charact. FSS Building of Concrete Samples Samples Characterization Containment Results Walls 4 6
  • Chapter 5 Containment

- Core Samples Mat 8 6 Required for Future In-Core 1 Taken GW dose calculation: Sump 4 Planned 4

(See Table at right)

Spent Fuel

- Additional Buried Pipe Pool 6 Planned 6 Release Values for Additional Pipe Sizes Cable Vault 7 6 20

Chapters Effected by LTP Amendment (Cont.)

  • Chapter 6

- Details of Basement Fill Model

- Method of Calculation of Dose - Basement Fill Model

- Summary of Brookhaven Concrete Diffusion Study

- Summary of Brookhaven Backfill Soil Kd Study 21

Summary and Schedule

  • Submittal of Amendment in September
  • Will Include

- Method to be used to Calculate Future Groundwater

- Estimate of Future Groundwater Dose based on Characterization Results to Date

  • Approval Needed by May 2005 to support Demolition Schedule
  • Questions/Discussion 22
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