U.S. Department of Energy, National Nuclear Security Administration Nevada Site Office –...

U.S. Department of Energy, National Nuclear Security Administration Nevada Site Office – Environmental Management


Nevada Test Site Low-Level Radioactive Waste Disposal

Operations

Stephen Mellington, Assistant Managerfor Environmental Management

June 7, 2006National Governor’s Association

79FY06 – 06/07/2006

• Approximately 1,375 square miles of federally owned and controlled land – surrounded by approximately 4,500 square miles of federally owned and controlled land

• Located approximately 65 miles northwest of Las Vegas, Nevada

The Nevada Test Site (NTS)

79FY06 – 06/07/2006

U.S. Department of Energy Site Comparisons

79FY06 – 06/07/2006

Arid desert climateAverage 4-6 inches annual precipitationEvaporation exceeds rainfall by 12 times

Depth to groundwater for disposal areasArea 3 – 1,600 feet (488 meters)Area 5 – 770 feet (235 meters)

Thick alluvial basinsNegligible recharge

Groundwater from past cooler/wetter climateNo “fast” pathways

Environmental Conditions

No significant surface waterNo permanent streams or lakes

Many closed basins

79FY06 – 06/07/2006

Historic Activities at the NTS

• First NTS atmospheric nuclear test detonated on January 27, 1951

• 928 atmospheric and underground nuclear tests conducted between 1951 and 1992

• Nuclear weapons development and testing generated radioactive waste

79FY06 – 06/07/2006

Early Disposal Activities

• Low-level radioactive waste (LLW) first collected for disposal at an Area 5 site in 1953

• LLW first disposed in Area 5 Sugar Bunker trench in 1961

• LLW first disposed in Area 3 subsidence crater in 1968

• Began accepting LLW generated by other U.S. Department of Energy sites in 1976

• Formal LLW disposal project established in 1978

79FY06 – 06/07/2006

Area 5Radioactive Waste Management Site

• Developed around the original Sugar Bunker trench

• 732 acres available for disposal – 140 acres currently used

• Disposal cells are excavated pits and trenches

• Eight (8) active disposal cells (21 closed and two constructed/available)

79FY06 – 06/07/2006

• Diverse radioactive waste streams and package types handled– Asbestos– Contact-handled LLW

monoliths (in excess of 90,000 pounds each)

– High-concentration thorium– Remote-handled LLW

monoliths– Roll-off intermodals– Thorium nitrate– Mixed LLW


(continued)

79FY06 – 06/07/2006


• Encompasses 120 acres

• Five (5) disposal cells (comprised of 7 subsidence craters)

• Radioactive waste managed includes LLW and Mixed LLW (cell closed)

• Subsidence craters from historic underground nuclear testing are used as disposal cells

79FY06 – 06/07/2006

Mixed LLW at the Nevada Test Site

• 1987: Mixed LLW disposal begins

• 1990: State of Nevada requires the U.S. Department of Energy to provide a Waste Analysis/Verification Plan

– Disposal of off-site generated Mixed LLW is halted

79FY06 – 06/07/2006

Mixed LLW at the Nevada Test Site (continued)

• 2000: DOE issues Waste Management Programmatic Environmental Impact Statement Record of Decision declaring the Nevada Test Site as a regional disposal site for LLW and Mixed LLW

• 2000-2005: DOE works with State to resolve technical issues affecting the acceptance of off-site Mixed LLW

• December 2005: State issues Nevada Test Site Resource Conservation and Recovery Act (RCRA) Part B Permit – lifting the off-site Mixed LLW disposal prohibition

79FY06 – 06/07/2006

Graphic Number:

/454/PICT0089.JPG

Photo Date:

4/11/2006

Mixed LLW at the Nevada Test Site (continued)

• April 11, 2006: Received first off-site MLLW shipment since 1990



Disposal Practices

79FY06 – 06/07/2006

NTS Requirements / Capabilities

• U.S. Department of Energy Order 435.1

• NTS Waste Acceptance Criteria (NTSWAC)

• Category 2 non-reactor nuclear facility

– Documented safety analyses

– Technical safety requirements

• All disposed waste containers are retrievable

– Grid coordinate tracking system for performance modeling and retrievability

79FY06 – 06/07/2006

Tailored Disposal Cells and Waste Forms• Unique waste streams of LLW require specialized

disposal cells– High-dose LLW– Non-standard waste packaging– Radon flux requirements– Classified materials

• Cells are designed and constructed prior to acceptance/receipt of waste on an as-needed basis

• Crane placement and heavy equipment requirements considered

• Approximately 200,000 cubic yards of soil moved each year to create custom disposal cells

79FY06 – 06/07/2006

Area 5 Disposal Cells –Waste Container Configuration

Boxes containing LLW are placed in a stair-stacked

configuration within a engineered grid

79FY06 – 06/07/2006

Area 5 Disposal Cells –Waste Container Configuration (continued)

LLW drums are positioned in a single layer with boxes of LLW

arranged as “book ends”

79FY06 – 06/07/2006

Area 5 Disposal Cells –Waste Container Configuration

(continued)

Remote-Handled Monoliths – 10 Rem/hour dose rates and higher

97 high-dose LLW monoliths (~20 R/hr) were received with a cumulative dose of 0.38178 man-Rem for 900 man-hours

Monoliths were “nested” in between LLW cargo containers arranged in

an H-pattern

79FY06 – 06/07/2006

Site Differences

• Area 3 Radioactive Waste Management Site located 15 miles northwest of Area 5

• Area 3 historically used for larger, bulk radioactive waste packages

• Layer-cake geometry used to dispose radioactive waste in Area 3

79FY06 – 06/07/2006


Cargo containers of LLW

79FY06 – 06/07/2006


Bulk equipment such as nozzles, compressors, converters, centrifuges, etc.

79FY06 – 06/07/200630 generators are currently approved to ship LLW to the NTS

General Atomics

NTS Approved LLW Generators

79FY06 – 06/07/2006

Mixed LLW Generators

Mound

WVDP

SRS

BNLLLNL

INL

SNL

Lexington

Paducah

Portsmouth

Perma-Fix

Oak Ridge(2)

Current

Potential

79FY06 – 06/07/2006

NTS LLW Disposal History

0

500

1,000

1,500

2,000

2,500

3,000

3,500

4,000

1980-1989*

1990-1999*

2000 2001 2002 2003 2004 2005 2006 2007 2008 2009 2010 2011

ForecastActual On-siteActual Off-site

Vo

lum

e (1

,000

ft3 )

1,67

4

Fiscal Year

2,42

2

FY 2003 (total) – 3,239,726 ft3

FY 2004 (total) – 3,743,572 ft3

FY 2005 (total) – 2,091,771 ft3

FY 2006 (total received as of 5/21/2006) – 790,933 ft3

*Indicates average per year for that decade

520

930

1,44

0 sh

ipm

ents

2,43

4

705

79FY06 – 06/07/2006

NSO Commitment

• NSO is committed to supporting accelerated cleanup by providing disposal services to all U.S. Department of Energy sites

• NSO is committed to reducing risk to NTS workers, the public, and the environment with timely, cost-effective disposal services

• NSO is committed to working cooperatively with regulators and keeping the public informed of its Environmental Management activities through the Community Advisory Board



Groundwater

79FY06 – 06/07/2006

Background Information• 1951 to 1992: United States

Government conducted 828 underground nuclear tests at the Nevada Test Site (NTS) at depths ranging from approximately 90 to 4,800 feet below the ground surface

• About one-third of these tests occurred near or below the water table, which resulted in some contamination of the area’s groundwater

79FY06 – 06/07/2006

Addressing Groundwater Contamination

• U.S. Department of Energy began preliminary hydrologic research in the 1970s

• A more intensive groundwater studies program was launched in 1989 with the formation of the Groundwater Characterization Project at the Department of Energy Nevada Site Office

79FY06 – 06/07/2006

Addressing Groundwater Contamination (continued)

• The Underground Test Area (UGTA) sub-project evaluates the historic testing impacts on groundwater resources and study the extent of contaminant migration

• The scope includes collection of multiple sources of field data in order to create a 3-D computer model

– This model includes groundwater, flow and transport parameters

• The models will be used to help create a monitoring network to ensure that the public/workers are not exposed to groundwater exceeding Safe Drink Water Act standards

79FY06 – 06/07/2006

UGTA Strategy• Drill wells, analyze existing wells, and

conduct geophysical studies to collect data

• Evaluated the NTS on a regional scale – separated areas hydrologically and geographically into five (5) manageable Corrective Action Units

• Develop phased approach – Phase I and Phase II each representing stages of data collection and analysis

• Identify contaminant movement and develop contaminant boundaries

• Implement recommendations provided by an independent peer review of the strategy

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