Building CSMs Presentation

EXAMPLE

Constructing ConceptualConstructing ConceptualSite Model (CSM) Diagrams using Site Model (CSM) Diagrams using

the Simulation Editorthe Simulation Editor

FRAMES-2.0 WorkshopU.S. Nuclear Regulatory Commission

Bethesda, MarylandNovember 15-16, 2007

Pacific Northwest National LaboratoryRichland, Washington

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IntroductionIntroduction

The Simulation Editor allows the user to drawn schematic diagrams depicting the Conceptual Site Model (CSM).The CSM is based on real-world icons depicting the flow path of the contaminant through from the release point, through various environmental media, to a receptor of concern.The Simulation Editor design is based on sequential modeling.Dynamic feedback (closed-loop) is handled within each module and is not a responsibility of the system.

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Rules of Thumb for Building CSMsRules of Thumb for Building CSMs

You can build any picture you want, but the models may not be able to exist within the scheme you build. Build step-by-step.

Many analytical and semi-analytical transport models only accept a single input.

A plus operator will most likely be required to handle multiple inputs from the same icon type, assuming the same DICs are produced by the upstream models.

Many exposure models accept multiple inputs (e.g., inhalation, ingestion, dermal contact, external dose); therefore, they may allow multiple connections.

Intake and Health Impact modules usually accept single input.

Establish standardized CSMs, if the CSMs are to be used repeatedly.

Lock models and databases, if these represent acceptable tools.

Start simple, then build on a base situation

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Start Simple(FRAMES -1.6 Example; sent by user)

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Conceptual Site Model #1Conceptual Site Model #1

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Step 1: Contaminants leaches from a landfill to the subsurface. Contaminants move through three vadose zones, through an aquifer, to Well #1, where water is withdrawn to irrigate Agricultural area #1 to feed Population #1.

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CSM #1: Step 1CSM #1: Step 1

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Conceptual Model #1Conceptual Model #1

Step 2: Precipitation events cause overland runoff from the landfill, which has surface contamination. The overland runoff flows into a nearby river. Water is withdrawn from the river, where Population #1, related to Agricultural Area #1, consume the water (i.e., drinking water).

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• Step 3: The wind blows across the top of the landfill causing suspension of contaminated particles into the air. Volatilization of organics into the air also occurs. The contaminants are transported through the air and contaminate a different Agricultural Area #2 through wet and dry deposition. This area is used to help feed Population #1.

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• Step 4: In addition to producing crops that are consumed by Population #1, Agricultural area #2 also produces crops that are consumed by Population #2.

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Conceptual Site Model #2Conceptual Site Model #2Pittsburgh is surrounded by three rivers (Monongahela, Allegheny, and Ohio). A known release, in violation of the an NPDES permit,

discharges to the Monongahela. A landfill leaches the same contaminant to the

Allegheny. Water is removed from both waterways to supply

potable water to the same population in the city.

What is the risk to the population from these two sources?Assume that the exposure module accepts only one input (i.e., same DIC).

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CSM #2CSM #2

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Step 1: There is a known discharge that contaminates an aquifer. The contamination moves through the aquifer to where water is withdrawn and used to irrigate Agricultural area #1. Crops are consumed by Population #1.

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Step 2: The contamination in the aquifer proceeds by the withdrawal well and continues to a near by river. Contamination enters the river, and Population 1 is exposed through recreational activities (e.g., swimming, boating, fishing, etc.).

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Step 3: There is a separate and known release of contaminates to the air, which is transported through the atmosphere to Agricultural Area #1, where Population 1 breathes the air.

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Step 4: Water is withdrawn from the river, and Population #2 uses the water as its potable water supply.

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Linking to theSensitivity/Uncertainty Module

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Step 1: Build the following Conceptual Site Model:

SourceVadose ZoneAquiferExposureIntakeRisk

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Step 2: Analyze parameter uncertainty, based on a Monte Carlo analysis. Vary input Kd in the vadose zone and correlate it to the peak mass flux rate from the vadose zone: Input parameter to Vadose Zone Model: Kd Output parameter from Vadose Zone model: Peak Mass Flux

Rate

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CSM #4: Step 2CSM #4: Step 2Vary Vadose Zone Kd (input) on vadose zone flux (output)

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Step 3: Analyze parameter uncertainty, based on a Monte Carlo analysis. Vary input Kd in the vadose zone, and correlated it to the peak aquifer concentration: Input parameter to Vadose Zone Model: Kd Output parameter from Aquifer: Peak Aquifer Concentration

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CSM #4: Step 3CSM #4: Step 3Uncertainty of vadose zone input Kd (input) on aquifer

concentrations (output)

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Step 4: Analyze parameter uncertainty, based on a Monte Carlo analysis. Input parameters:

Vary the source-term inventory Vary input Kd in the vadose zone

Output parameters: Peak Concentration from Aquifer Module Peak Risk from Health Impacts Module

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SummarySummary

Schematic of the Conceptual Site ModelBased on real-world IconsEasy to quickly describe and understand the CSMEasy to convey the problem to stakeholdersEasy to archive for QA/QCEasy to changeThere are also ways in which two-stage Monte Carlo analyses can be performed but were not shown.

Building CSMs Presentation

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