Defining End State and Exit

Strategy Approaches

Michael Truex

October 30, 2018

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Outline

• Context and remediation management challenge

• Example exit strategies and integration with site management

• Monitoring considerations

• International Atomic Energy Agency (IAEA) efforts on end states

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Context

• Recent documents recognize subsurface remediation complexities and identify site management approaches to address challenges

http://rmcs-1.itrcweb.org National Research Council 2013

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ContextInterstate Technology

and Regulatory Council

(ITRC) Remediation

Management

of Complex Sites

Bunn et al., 2012

http://rmcs-1.itrcweb.org

EPA Superfund Task

Force Recommendation

#3: Broaden the Use of

Adaptive Management

www.epa.gov/superfund/

superfund-task-force

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Remediation Management of Complex Sites

• Remediation Management of Complex Sites: Adaptive Site Management Adaptive approaches are needed

when site complexities render remediation uncertain and a stepwise approach is needed

The stepwise approach capitalizes on information gained along the way

Interim and site objectives are used to define a path toward closure

http://rmcs-1.itrcweb.org

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Remediation Management Challenge

• Active remediation needs to be managed

Meet performance objectives

With an exit strategy in mind (e.g., transition to passive remediation)

• Performance monitoring is needed to support remedy decisions (adaptive management) and an exit strategy

• An end state needs to be defined to set site objectives

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Exit Strategies

Truex et al., 2015, 2017

Truex et al., 2013

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SVE Exit Strategy Application

Hanford Soil Vapor Extraction

Treatment Termination

DOE 2014, 2016

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P&T Exit Strategy Application

Hanford P&T Performance Monitoring Plan (Decisional Draft)

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Monitoring Advancements

• Consideration of monitoring is integral with end states and exit strategies

Strickland et al. 2018

Bunn et al., 2012

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IAEA End State Efforts

• Determination of Environmental Remediation End States (DERES)

A resource and guide for the process of determining an appropriate environmental remediation end state

Intended audience are site owners/operators, regulators, policy makers, decision makers, and stakeholders/interested parties

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IAEA DERES Document

• DERES Document Scope

describe a process for determining an end state for environmental remediation and to address facilities or structures through decommissioning activities

considers reduction or mitigation of radiological risks, chemical risks, socio-political and regulatory factors, and structural or other factors related to reaching an end state that is suitable for the intended future use of the site

may also be relevant for the decommissioning of facilities of the nuclear fuel cycle and NORM

does not include development of specific remediation or decommissioning plans

does not include selection of specific technologies

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IAEA DERES Document

• DERES Document Content

Definition of terms

Aid for communication

A flow chart of the end state determination process

Description of flow-chart elements and links to resources

Recommendations for stakeholder involvement

Optimization approaches for end state determination

Developing and refining options

Approaches for describing the characteristics of different end state options so that they can be compared

Costs and benefits

Balance of risk

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IAEA DERES Document

• DERES Document Content

Considering uncertainties

Making decisions with limited information

Predicted performance of remediation activities

Use of interim states as adaptive steps toward the end state

Managing implementation

Consideration of life-cycle elements

Short term activities and long-term requirements (e.g., monitoring needs)

Documentation of end state plan

Transition to implementation

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IAEA DERES Document

• Exposure Situations

Emergency Exposure Situation

Apply DERES after emergency response

Existing Exposure Situations

Primary DERES target

Planned Exposure Situations (managed nuclear facility)

Likely have defined end state in decommissioning plan

Some elements of the site may need DERES

• Incorporate IAEA Principles of Radiation Protection

Management of radiological materials, facilities, and contamination

risk and exposure limits

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IAEA DERES Document

• Regulatory Requirements

Prescriptive regulations (strict requirements)

Optimization approaches (balance of risks)

Context

National strategies for radionuclide site remediation

International regulations and principles

Establishing roles and responsibilities of regulators and site owners

Stakeholder involvement

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DERES Process

• Decisions and Actions

Need for action

Conceptual Site Model

Develop and evaluate options

• Information and Analysis

Factors for consideration

Site-specific information

Analysis to support decisions

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DERES Process

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DERES Process

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References

Bunn AL, DM Wellman, RA Deeb, EL Hawley, MJ Truex, M Peterson, MD Freshley, EM Pierce, J McCord, MH Young, TJ Gilmore, R Miller, AL Miracle, D Kaback, C Eddy-Dilek, J Rossabi, MH Lee, RP Bush, P Beam , GM Chamberlain, J Marble, L Whitehurst, KD Gerdes, and Y Collazo. 2012. Scientific Opportunities for Monitoring at Environmental Remediation Sites (SOMERS): Integrated Systems-Based Approaches to Monitoring. PNNL-21379, Pacific Northwest National Laboratory, Richland, WA.

DOE. 2016. Endpoint Evaluation for the 200-PW-1 Operable Unit Soil Vapor Extraction System Operations. DOE/RL-2014-48 Rev. 0, U.S. Department of Energy, Richland Operations Office, Richland, Washington.

DOE. 2014. Path Forward for Future 200-PW-1 Operable Unit Soil Vapor Extraction Operations. DOE/RL-2014-18 Rev. 0, U.S. Department of Energy, Richland Operations Office, Richland, Washington.

National Research Council (NRC). 2013. Alternatives for Managing the Nation’s Complex Contaminated Groundwater Sites. National Academies Press, Washington, D.C.

Strickland, CE, MJ Truex, RD Mackley, and TC Johnson. 2018. Deep Vadose Zone Monitoring Strategy for the Hanford Central Plateau. PNNL-28031, Pacific Northwest National Laboratory, Richland, WA.

Truex, MJ, DJ Becker, MA Simon, M Oostrom, AK Rice, and CD Johnson. 2013. Soil Vapor Extraction System Optimization, Transition, and Closure Guidance. PNNL-21843, Pacific Northwest National Laboratory, Richland, WA.

Truex, MJ, CD Johnson DJ Becker, MH Lee, and MJ Nimmons. 2015. Performance Assessment for Pump-and-Treat Closure or Transition. PNNL-24696, Pacific Northwest National Laboratory, Richland, WA.

Truex, MJ, CD Johnson, DJ Becker, K Lynch, T Macbeth, and MH Lee. 2017. Performance Assessment of Pump-and-Treat Systems. Ground Water Monitoring and Remediation. doi: 10.1111/gwmr.12218