Panel discussion of engineered barriers
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Panel Discussion of Engineered Barriers. Ernest Hardin (Moderator) Sandia National Laboratories, Lead Laboratory Yucca Mountain Project. SAND #: 2008-7211P. TOPICS. Compare EBS concepts developed for different settings How to demonstrate EBS capability?

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Panel discussion of engineered barriers

Panel Discussion of Engineered Barriers

Ernest Hardin (Moderator)

Sandia National Laboratories, Lead Laboratory

Yucca Mountain Project

SAND #: 2008-7211P


Topics

TOPICS

  • Compare EBS concepts developed for different settings

  • How to demonstrate EBS capability?

  • How to select the spent-fuel repository EBS design?

Panelists

  • Chris White, U.S. Department of Energy

  • Peter Baumgartner, Atomic Energy of Canda, Ltd.

  • Neil Brown, Los Alamos National Laboratory

  • Ernest Hardin, Sandia National Laboratories (moderator)


Ebs panel discussion

EBS Panel Discussion

  • What is an Engineered Barrier System?

    • Canadian EBS design: 1) the sealing system, 2) the container system and 3) the spent fuel.

    • KBS-3 EBS design: 1) sealing system including backfill and buffer material, 2) waste container, and 3) spent fuel.

    • Yucca Mountain EBS design: 1) emplacement drift, 2) drip shield, 3) container system, and 4) waste forms.

  • What are the EBS functions?

    • 1) limit contact of groundwater with waste or waste containers (in conjunction with natural barriers),

    • 2) limit rates of radionuclide release from waste forms, and

    • 3) limit rates of release to the natural system (in conjunction with natural barriers).


Disposal concept examples

Disposal Concept Examples

Yucca Mountain and KBS-3 Repositories


Ebs design principles hydrologic environment

EBS Design Principles - Hydrologic Environment

Saturated

  • Liquid water as transport vector

  • Long-range hydraulics

  • Small hydraulic gradient (after equilibration)

  • Near-field as hydro-barrier (e.g., salt or bentonite)

  • Material interactions limited by transport through near-field barriers

  • Seals influence movement to/from waste containers

Unsaturated

  • Liquid water as transport vector

  • Predominantly vertical flow

  • Fixed flow potential gradient

  • EBS drains freely; use repository “grade plan”

  • Material interactions are limited by patterns of vertical drainage

  • Sealing limited to backfilling


Ebs design principles performance of ebs features

EBS Design Principles - Performance of EBS Features

Saturated

  • Sealing System

    • Limit water contacting container

    • Stagnate water around containers

    • Seal important locations

    • Use sorptive materials

  • Container System

    • Limit water contacting waste form

    • Structural strength

    • Resist degradation (corrosion)

    • Feasible/flexible

  • Spent Fuel Waste Form

    • Rate limited degradation

    • Solubility limited release (redox)

    • Retarded diffusive release

Unsaturated

  • Sealing System

    • Backfilling of shafts, boreholes, and access tunnels only

  • Container System

    • Limit water contacting waste form

    • Structural strength

    • Resist degradation (corrosion)

    • Feasible/flexible

  • Spent Fuel Waste Form

    • Rate limited degradation

    • Solubility limited release

    • Retarded diffusive release


Ebs design principles thermal chemical environment

EBS Design Principles - Thermal-Chemical Environment

Saturated

  • Reducing environment

    • Buffer as micro-environment

    • Reducing minerals in host rock

  • Waste package environment

    • Controlled by buffer

  • Heat transfer

    • Conduction dominated

    • T < boiling preserves clays (or other water-sensitive EBS materials)

  • Radionuclide transport

    • Diffusive release into natural system

    • Naturally occurring materials

Unsaturated

  • Oxidizing environment

    • Gas exchange with atmosphere

    • Oxidizing minerals

  • Waste package environment

    • Controlled by host rock

  • Heat transfer

    • Conduction dominated; radiative across air gaps

    • T > boiling possible

  • Radionuclide transport

    • Diffusive release into natural system

    • EBS degradation


Demonstrating ebs capability

Demonstrating EBS Capability

  • Underground laboratories are needed to demonstrate EBS capability

    • Aspö Hard Rock Laboratory

    • Underground Research Laboratory

    • Exploratory Studies Facility

  • International collaboration

  • Pilot-scale initial/confirmatory testing of spent-fuel disposal

    • Salt Vault (1965)

    • Spent Fuel Test - Climax (1982)

    • SKB’s SFR-1 project (planned)

    • U.S. DOE Performance Confirmation (planned)


Spent fuel test climax

Spent Fuel Test - Climax

Unsaturated quartz monzonite, Climax stock, Nevada Test Site

Canister Drift, Transfer Vehicle

Receiving Room, Canister Borehole


Yucca mountain performance confirmation program thermally accelerated drift concept

Yucca Mountain Performance Confirmation ProgramThermally Accelerated Drift Concept

Source: TDR-PCS-SE-000001 Rev. 05, Fig. 3-1


Yucca mountain repository design selection 1999

Formulate

Enhanced

Alternatives;

Analyze

  • Reference Design

  • Alternatives:

  • Low thermal

  • Postclosure ventilation

  • Enhanced access

  • Emplacement modes

  • Modular/phased

Design

Selection

Evaluation Criteria:

Preclosure performance

Postclosure performance

Assurance

Engineering acceptance

Construction/operations/maintenance

Environmental

Schedule

Cost

Independent

Design

Features

& Analysis

Yucca Mountain Repository Design Selection (1999)

Boundary conditions: sited in unsaturated, fractured, welded tuff; spent fuel and defense waste streams; previous conceptual design work.


Yucca mountain repository design selection

Yucca Mountain Repository Design Selection

Independent Design Features Included:

2. PACKAGING

  • Corrosion resistant materials

  • Ceramic coatings

  • Canistered assemblies

  • Rod consolidation

  • Waste package fillers

  • Canistered assemblies

1. CONFIGURATION/THERMAL

  • Thermal loading/aging/blending

  • Preclosure ventilation

  • Postclosure ventilation

  • Drift and package diameters

  • Waste package spacing

  • Backfill

  • Shielding/self-shielding options

  • Ground support options

3. ISOLATION

  • Drip shield

  • Richards barrier

  • Diffusion barrier

  • Getters

  • Rock pre-treatment


Ebs design panel discussion

EBS Design Panel Discussion

  • Repository programs have demonstrated the feasibility of EBS concepts for geologic disposal

  • Different EBS designs for unsaturated vs. saturated hydrologic conditions; different sealing strategies

  • Other design issues:

    • Spent fuel vs. HLW glass and other waste forms

    • Criticality control

    • Performance assessment requirements

    • Retrievability

  • Need for demonstration in situ, e.g., at pilot scale

  • Design selection involves multiple, non-technical factors


Ebs design panel discussion1

EBS Design Panel Discussion

Backup Slides on Yucca Mountain Repository Design Selection


Ebs design alternatives a low thermal

Point Load

Line Load

EBS Design Alternatives - A. Low thermal

See also: Aging/blending, and drift/package diameter design features

Source: B00000000-01717-4600-00123 Rev. 01


Ebs design alternatives b postclosure ventilation

Warm air

Natural air circulation in one postclosure loop

Cool air

Waste

packages

Emplacement drift

Vertical vent raise

Waste

packages

Open

Closed - Triangle

EBS Design Alternatives - B. Postclosure ventilation

Source: B00000000-01717-4600-00123 Rev. 01


Ebs design alternatives c enhanced access

Pedestal

(or rail car)

Waste package

Pedestal

(or rail car)

Waste package

Ground

support

Temporary

concrete cover

Waste

package

support

Waste package

on supports

Pedestal

(or rail car)

Waste package

EBS Design Alternatives - C. Enhanced Access

Source: B00000000-01717-4600-00123 Rev. 01


Ebs design alternatives d emplacement modes

Crowned

invert

Plug

Plug

Waste package

Lined

borehole

Waste package

Waste

package

support

Invert

EBS Design Alternatives - D. Emplacement modes

Source: B00000000-01717-4600-00123 Rev. 01


Ebs design features 1 f backfill

Granular Backfill

Emplaced at Closure

EBS Design Features - 1 f) Backfill

Source: B00000000-01717-4600-00123 Rev. 01


Ebs design features 2 a corrosion resistant materials

Alloy 22

Alloy 22

Titanium

Titanium

Titanium

Alloy 22

EBS Design Features - 2 a) Corrosion resistant materials

Source: B00000000-01717-4600-00123 Rev. 01


Ebs design features 2 e waste package fillers

Steel Shot or

Iron Oxide

Thickened

Carbon Steel

Supports

Granular Filler

Integral Filler

EBS Design Features - 2 e) Waste package fillers

Source: B00000000-01717-4600-00123 Rev. 01


Ebs design features 3 a drip shield

Drip

Shield

Drip Shield

Emplaced

at Closure

Granular

Backfill

Emplaced at

Closure

Granular

Backfill

Emplaced at

Closure

Borttom of

Drip Shield

End Plate

EBS Design Features - 3 a) Drip shield

Source: B00000000-01717-4600-00123 Rev. 01


Ebs design features 3 b richards barrier

Fine-Grained

Backfill Emplaced

at Closure

Coarse-Grained

Backfill Emplaced

at Closure

EBS Design Features - 3 b) Richards barrier

Source: B00000000-01717-4600-00123 Rev. 01


Ebs design features 3 c diffusion barrier

Coarse-Grained

Backfill Emplaced

at Closure

Diffusive Barrier Placed

During Construction, Prior to Emplacement of Waste Packages

EBS Design Features - 3 c) Diffusion barrier

Source: B00000000-01717-4600-00123 Rev. 01


Ebs design features 3 d getters

Fine-Grained Backfill

Emplaced at Closure

Getter Material Placed

During Construction, Prior

to Emplacement

of Waste Packages

EBS Design Features - 3 d) Getters

Source: B00000000-01717-4600-00123 Rev. 01


Ebs design panel discussion2

EBS Design Panel Discussion

Backup Slides on History of EBS Design Development in the U.S. Spent Fuel/HLW Repository Program


Short history of ebs design developments in the u s spent fuel repository program

Short History of EBS Design Developments in the U.S. Spent Fuel Repository Program

  • Background: Project Salt Vault (1967)1,2 and R&D at Avery Island (1982)

  • Spent Fuel Test - Climax (1983)1

  • Basalt Waste Isolation Project (1987)2

  • Salt Repository Project (1987)2

  • Yucca Mountain Site Characterization Plan Conceptual Design (1988)2

  • Viability Assessment (1998)2

  • Yucca Mountain License Application (2008)2

    1Advanced to in situ testing with spent fuel2Includes a conceptual EBS design for spent fuel/HLW disposal


Spent fuel test climax1

Pit Liner

Concrete Shield Plug

Granite

Concrete

Steel Shield Plug

Grout

Canister Support Pin

Liner Assembly

Canister

Grout

Spent Fuel Test - Climax

Near-Field Configuration and Facility Layout

Source: SFT-C Final Report (NNA.19870901.0052) Figures 1-1 and 12-3.


Basalt waste isolation project 1987

CONTAINER

PRE-FORMED PACKING

CLOSURE

PLATE

SHELL

CONSOLIDATED

SPENT FUEL

RODS

HOST ROCK

Basalt Waste Isolation Project (1987)

Horizontal Emplacement Reference Concept (not shown: backfill, seals)

Source: BWIP CDR (HQZ.890410.1107) Figure 2.1-1


Bedded salt repository ebs design 1987

Entry and Emplacement Hole

Emplacement

Hole

Emplacement Hole Container

Counterbore

Salt Backfill Shield

Emplaced Disposal Container

Disposal

Container

Borehole

VERTICAL SECTION

Crushed Salt Packing

Material in Annulus

Crushed Salt Pad

Bedded Salt Repository EBS Design (1987)

Horizontal and Vertical Emplacement Options

(not shown: backfill, seals)

Sources: Salt Repository CDR

(vertical: MOL.20061122.0125, and horizontal: MOL.20061214.0266)


Yucca mountain site characterization plan conceptual design 1988

Borehole Cover

Shield Plug

Liner

Cover

Standoff

Emplacement Drift

Crushed Tuff

Backfill

Emplacement

Drift

Shield Plug

Partial Liner

Waste Container

Support Plate

Yucca Mountain Site Characterization Plan Conceptual Design (1988)

Horizontal and Vertical Emplacement Options

Source: SAND84-2641 (HQS.19880517.0945) Figures 3-12 and 3-13.


Yucca mountain repository viability assessment 1998

Yucca Mountain Repository Viability Assessment (1998)

Conceptual EBS Design

Source: DOE/RW-0508, Figures 5-1 and 5-2.


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