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RESRAD-BUILD Presentations
Environmental Science Division
Argonne National Laboratory
April 11-12, 2011
RESRAD-BUILD Workshop
2
RESRAD-BUILD Workshop Overview
Introduction to RESRAD-BUILD– Comparison of RESRAD and RESRAD-BUILD
– History of RESRAD-BUILD development
– Overview of RESRAD-BUILD pathways
– Pathways considered
– Sources and receptors considered
– Building Geometry
– Code requirements
– Supporting documentation
Demonstration
3
RESRAD-BUILD Workshop Overview
Methodology– Time integration– Source Geometry– Source/Receptor Specification– Coordinate system– Source removal and injection– Air flow model– Dose calculations for each pathway– Special models for tritium and radon– Guideline Development
Output ResultsProblem Solving TechniquesVerification of RESRAD-BUILDRESRAD-BUILD Configuration Control
Introduction to RESRAD-BUILD
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Comparison of RESRAD and RESRAD-BUILD
RESRAD (soil) and RESRAD-BUILD (building) codes address different contamination sources and uses: – Soil contamination which might lead
to contamination of food and water through movement by natural processes
– Building contamination in man-made products and air-flows which might lead to exposure during normal building occupancy or D&D activities
6
History of RESRAD-BUILD Development
Motivation for RESRAD-BULD– Increased D&D activity
– Limitations of regulatory guidelines
– Movement towards dose-based release criteria
Development History of RESRAD-BUILD– DOS version released Dec. 1994
– Windows version released July 1996
– Uncertainty module upgraded Sep 2000
– Currently at version 3.5
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The Potential Problem with Concentration Based Regulations
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Removal of contaminated material– Time (source life time)
– Fraction
Fate of removed material– Disposed of
– Released in to air
Fate of material released to air– Deposition of surfaces
• Resuspension
– Moved by air circulation• From room to room
• Out of building
Processes Considered in RESRAD-BUILD
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External– Direct
– Deposition
– Immersion
Ingestion– Direct
– Deposition
Inhalation– Airborne particulates
• Resuspension
– Radon
Pathways Considered in RESRAD-BUILD
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Sources and Receptors Considered
Four distinct source types– Point
– Line
– Area• Circular
• Rectangular
– Volume• Cylindrical
• Rectangular prism
Ability to co-locate sources– Area source above a volume source
– Hot-spot in an area source
Up to 10 sources in a single run
Up to 10 receptors in a single run
11
Building Geometry in RESRAD-BUILD
1-RoomWarehouse
2-Room House
3-Room House
2-StoryHouse 2-Story Building with
2 Rooms on the First Floor3-StoryHouse
2-Story Housewith Basement
(No air exchangebetween basement
and outdoors)
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RESRAD-BUILD Computer Requirements
Microsoft Windows platform– Windows 2000
– Windows XP
– Windows Vista
Requires active internet connection for download– http://www.evs.anl.gov/resrad/
19 MB downloadable file
Current Version: RESRAD-BUILD 3.5
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RESRAD-BUILD Manual Version 3
Updated descriptions of sources, receptors and roomsUpdated users guide Procedure for performing probabilistic analysisMathematical modelsParameter descriptions
– Name– Range– Default
• Deterministic• Probabilistic
– Measurement Methodology
RESRAD-BUILD Demonstration
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RESRAD-BUILD Problem Demonstration
RESRAD-BUILD Methodology
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RESRAD-BUILD Time integrated Dose Calculations
Calculates an average concentration of the radionuclide over the exposure duration– Average calculation based on the
number of integration points selected
– Larger number of integration points are required for longer exposure times or short source lifetimes
– Integration point set to 1 calculates the instantaneous dose and projects the dose over the entire exposure duration• May overestimate the dose when the
source lifetime is small
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Source Geometry
Source Types– Point
– Line
– Area
– Volume
Source Geometry– Area source
• Circular
• Rectangular
– Volume source• Cylindrical
• Rectangular
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Receptor & Source Specifications
Receptor– Room in which he/she is located
• 1, 2, 3– Center point of receptor
• X, Y, Z coordinates in space• Usually 1 m above “floor”
Point source– Room in which it is located– X, Y, Z coordinates in space
Line source– Room in which it is located– Center point of line source
• X, Y, Z coordinates in space– Length of the source– Orientation of source
• X, Y or Z
(0,0,0)
(1,1,1)
2m
(1,1,-1)
X
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Area Source Specifications
Area source– Room in which it is located
• 1, 2, or 3
– Center point of the source• X, Y, Z coordinates in space
– Direction normal or perpendicular to the surface of the source
– Circular source• Area of the source
– Rectangular source• Lengths of sides
(0,1,1)
Y Direction
3.3 m
10 m
(3,2,2)
24 m2
X
Z
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Volume Source Specifications
Volume source– All area source specifications from
previous slide• Room in which it is located• Center point of the source• Direction normal or perpendicular to the
surface of the source• Area of circular source• Lengths of sides of rectangular source
– Number of regions in the third dimension• Up to 5 regions
– Region 1 will be closest to (0,0,0)
– Region where contamination exists• Only 1 contaminated region per source
– Thickness, density and erosion rate of each region
(0,1,1)
Y Direction
3.3 m
10 m
(3,2,2)
24 m2
X
Z
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RESRAD-BUILD Coordinate System
Rectangular coordinate system
Origin of coordinate system is chosen by the user – Not specified in the code
– Should not coincide with the center of a volume source
– For any volume source, the region closest to the origin has to be region 1
Helpful Hints– Have a drawing of the rooms
you want to model
– Base distances from a room corner
– Negative Z distances couldinfer a building with a basement
(0,0,2)Z
(2,0,2)
(3,0,3)Y
(4,1,2)X
(0,0,0)
Z
X
Y
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“Rotated” Coordinate Systems
Coordinate systems may be rotated (with respect to the walls) – For example, if a contaminated
pipe runs along the diagonal of a room
If multiple sources are present then RESRAD-BUILD may have to be run more than once.– If the sources can not all be
described by the same coordinate system
Source
ReceptorSour
ce
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Models the release of the radionuclides from the source to the air
– Building renovation– Building occupancy
The airflow in the building will transport the airborne nuclides from room to room
Nuclides will deposit and will be resuspended
Pathways considered– External
• Submersion, deposited nuclides
– Inhalation– Ingestion
• Deposited nuclides
Source Injection to Air Pathways
25
RESRAD-BUILD One Room Air Flow Model
V dC/dt = I - QC - VC + VCP - DVC + RDVC / ( R+)
Change of Activity in the room
Injection Rate
Exchange with outside
Decay in Air
Decay of parent in Air
Deposition
Resuspension
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Three Room Air Flow Model
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Source Removal/Injection - Point, Line, Area Sources
Source removal and injection treated the same for point, line and area
Parameters affecting source removal– Removable fraction– Source lifetime
Parameters affecting source injection– Source lifetime– Removable fraction– Air fraction
Source is linearly removed over the source lifetime– “Erosion Rate” or removal rate
• Removable Fraction/ Source Lifetime• 20% over 10 years
– 2% per year
Radioactive decay occurs simultaneously
Removable fraction
Fraction remaining “fixed”
Fraction remaining “fixed”
Air fraction × Removable fraction
Lifetime
Removed from building
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Source Removal/Injection-Volume Source
In a multi-region source, the regions erode in order– Region 1 first, region 2 next and so on– User specifies the regions– Region 1 is closest to 0,0,0
• Used to compute direct external radiation
Removal calculated using the erosion rate (cm/d), area (m2) and the bulk density of the material (g/cc)
Injecting calculated by applying the air fraction to the quantity removed
(1,1,1)
Region 1 Region 2
(2,1,1)
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Calculation of Injection Rate
5 m2 Area Source U-238 @ 100 pCi/m2
Source lifetime =3650 days Removable fraction =0.1 (10%) Air fraction =0.01 (1%) Calculate the injection rate Calculate the amount of U-238 remaining
after 10 years (neglect radioactive decay)
● Total Activity● 5*100 = 500 pCi of U-238
● Removal rate per day● 500*0.1/3650 = 0.0137 pCi/day
● Injection rate● 0.0137*0.01/24/60/60 = 1.59E-9 pCi/s
● Total activity remaining● 100*0.9 = 90 pCi/m2
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RESRAD-BUILD Example 1
Input the following into RESRAD-BUILD and compare the results with the last slide.– 5 m2 Area Source– U-238 @ 100 pCi/m2
– Source lifetime = 3650 days– Removable fraction = 0.1– Air fraction =0.01– evaluation time of 10 years– Run the code and check the code
calculated values of • injection rate
– View Last Detailed Output
• the amount of U-238 remaining after 10 years
– View Last Report
31
Direct External Pathway
FGR 12 External Dose conversion FactorsCorrected for:
– Finite area
– Finite thickness
– Density
– Shielding • thickness
• density
• material
32
The Direct External Pathway
A single shield is allowed between each source receptor pair– 10 Sources– 10 Receptors– 100 Source shield combinations
Users may wish to use a composite shield if multiple shields are present
Shielding by uncontaminated regions of volume sources is also modeled– thickness– density– region 1 is closest to origin
33
Direct Ingestion Pathway
Receptor MUST be in the same room as the source
Removable fraction must be greater than 0
Models the incidental ingestion of contaminated material
FGR 11 dose conversion factors
User must ensure mass balance– See next slide
34
Calculation of Direct Ingestion
RESRAD-BUILD does not perform a mass balance when computing the direct ingestion dose
– Can end up modeling a situation where the quantity ingested is more than the removable part or even the entire source
Direct ingestion rate is the fraction of the removable portion of the source ingested per hour (point, line, area)
Direct ingestion rate is in grams per hour for volume sources of the portion that is removable
30
locationreceptor at fraction Time ctionIndoor Fra duration Exposure 24
(hours) locationreceptor at Time
nnniI DCFStD RateIngestionTime Ingestion)(
35
Inhalation
Models the inhalation of particulates
Removable fraction and Air fraction determine respirable fraction– Only removable fraction ×
airborne fraction is considered in the inhalation dose
– Balance of the removable material is removed from the building and is not considered in RESRAD-BUILD
Includes resuspension of deposited material
Air quality model is used to estimate the airborne concentration
36
Inhalation
Source and receptor may be in different rooms
Does not depend on exact location within the room
Inhalation dose based on 1 m particle size
FGR 11 inhalation dose conversion factors
Dose is integrated over the exposure duration– Average concentration in
air over the exposure duration
37
Ingestion of deposited material
Models indirect ingestion of particulates deposited from air– Ingestion dose dependents
on removable fraction and air fraction
– If material is removed but not airborne RESRAD-BUILD will ignore this portion
Air quality model calculates the concentration of the deposited radionuclides
Ingestion rate for indirect ingestion is in units of m2
per hour
38
Ingestion of deposited material
Source and receptor may be in different rooms
Does not depend on exact location within the room
FGR 11 Ingestion dose conversion factors
Dose is integrated over the exposure duration– Average deposited
concentration over the exposure duration
Dose from direct ingestion and indirect ingestion are summed and reported as a single ingestion dose– direct and indirect
ingestion rates can be independently set to zero
39
External exposure from air borne and deposited nuclides
External dose from– Deposition
– Submersion
– dependents on air fraction and removable fraction
Air quality model calculates the concentration in air and the concentration of the deposited radionuclides
FGR 12 external dose conversion factors
Dose from deposition corrected for finite area
No shielding considered in the deposition dose
40
External exposure from air borne and deposited nuclides
Source and receptor may be in different rooms
Not based on exact location within a room
Dose from submersion is small compared to deposition
Dose is integrated over the exposure duration– Average deposited
concentration over the exposure duration
41
RESRAD-BUILD Example 2
Demonstration of the air pathways 1 Source, 3 ReceptorsModel Ra-226 using a point source -10 pCi 2 Room model
– Room 1 36 m2
– Room 2 100 m2
Source 1 in room 1 (5, 5, 0)Receptor 1 in room 1 (1, 1, 1)Receptor 2 in room 2 (3, -5, 1)Receptor 3 in room 2 (6, -8, 1)What is the external, inhalation and
ingestion dose to receptors 2 and 3?How do the doses compare with the dose
to receptor 1?
Source 1
Receptor 1
Receptor 2
Receptor 3
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RESRAD-BUILD Example 2
Sensitivity on– release fraction– air fraction– lifetime
With and without direct ingestion– for all receptors
With and without shielding from wall between rooms– Sensitivity on density– Can vary material type
Default air exchangeHigh air exchange between rooms
Source 1
Receptor 1
Receptor 2
Receptor 3
43
Special Models for H-3: Point Line & Area
Point, Line, Area Sources– Modeled similar to other
radionuclides– Removable fraction should be set
to 1 to model the complete release of tritium vapor (HTO)
– Air fraction should be set to 0.1– Deposition velocity of HTO should
be set to 0• There will be no deposition• Resuspension rate not considered• Indirect ingestion rate not
considered
Dermal absorption is modeled by increasing the inhalation dose by 50%
Air fraction
Removable fraction
Fraction remaining “fixed”
Fraction remaining “fixed”
44
Special Models for H-3: Volume Source
Models the vaporization of HTO– Assume equilibrium conditions– Diffusion of HTO from the source
to the indoor air– As humidity increases diffusion
decreases– Larger the moisture content
lower the H-3 content in the water
Fraction available for vaporization– Default 1.0
H-3 in solid form is released through erosion
Pathways considered– Inhalation– Ingestion– Dermal absorption
Wet Zone ThicknessDry Zone Thickness
45
Special Models for Radon
Point, Line and Area– Calculation of the injection rate is
similar to other point line and area sources.
– Uses the emanation fraction for the release fraction.
Volume Source– Models the diffusion of radon from
a single contaminated region through up to 4 uncontaminated regions.
– Source is only in ONE room• Can not diffuse the source into two
roomsRadon Flux
Radon Flux
46
RESRAD-BUILD: Risk Calculations
RESRAD-BUILD allows users to calculate cancer risk– FGR 13 mortality
– FGR 13 morbidity
– HEAST 2001 morbidity
– User library
Methodology is the same as the dose calculations– Same external model
– Same injection model
– Same air quality model
47
Guideline Development
Users must develop guideline values for each source type
Units of guideline values– Activity per mass (Volume
Source)• pCi/g
– Activity per area (Area Source)• DPM/m2
– Activity per length (Line Source)• pCi/m
– Activity (Point Source)
Use RESRAD-BUILD to develop DSRi(t)
)()(
tDSR
HtG
i
Ei
Gi(t) Single Radionuclide GuidelineHE Dose Limit (25 mrem/yr)DSRi(t) Dose to Source Ratio
(mrem/yr // Unit Concentration)
48
Output Results
RESRAD-BUILD provides users with graphical and text based results– Summary report provides
• Parameter Used
• Source term
• Dose
– Detailed Report• Intermediate calculations
involving airflow
• Injection rates
• External dose parameters
– Graphical Results• Interactive plotting
Problem Solving Techniques
50
Multiple Receptors in a Building
RESRAD-BUILD can be used to model multiple receptors in a building to obtain a collective dose
More realistically model a single individual performing multiple tasks at multiple locations
0.9 0.5
1.0
0.3 0.2
.5
51
Co-Locate Volume and Surface Sources
With up to 10 sources available in a single run, RESRAD-BUILD can allow users to model surface contamination and volumetric contamination in a single run
Use the same coordinates and source parameters to co-locate a volume and a surface source
52
Building Occupancy vs. Building Renovation
Building Occupancy Scenarios– Low release over a long
period of time
– Material that is more likely to become airborne
– Exposure duration is typically one year
Building Renovation– Large release over a short
time
– Airborne fraction lower than building occupancy
– Exposure duration 30 to 90 days
53
Multi-Room Air-Flow Model Input
Easy way to provide air-flow into the RESRAD-BUILD Computer Code
Automatically calculates room exchange rates, and overall building air exchange rate
Allows users to visualize airflow within a building
Provide instantaneous feedback when airflows are inconsistent
54
RESRAD-BUILD Example 3
Model the following scenario in RESRAD-BUILD– Pu-239 in a laboratory hood
– Laboratory• 36 m2 , 2.5 meters
– Laboratory hood• 1 m2 , 3 meters
– Hallway • 30 m2, 2.5 meters
– Air-flow is from the hallway to the room and out through the laboratory hood• There is no airflow from the hood
into either the room or the hallway
Laboratory
Laboratoryhood
Hal
lway
Receptor 1Receptor 2
55
Three-Dimensional Display
Allows users to visually place sources and receptors to model building geometry
Sources and receptors are color coded to room location
Sources are displayed as icons and do not represent the entire source– Volume Source: Square– Area Source: Circle– Line Source: Thin
Rectangle– Point Source: Point
56
Dose Conversion and Slope Factors
Shared Nuclide Dose Conversion Factor Database– Access to more complete set of nuclides
– Ability to construct “site-specific” DCF libraries
– Ability to use in both RESRAD and RESRAD-BUILD
– Editor has no equilibrium assumptions built in
– RESRAD-BUILD automatically constructs DCFs with a 30-day half-life cutoff equilibrium assumption
Risk calculation– Uses same exposure time for dose and risk
– Risk slope factors are applied
RESRAD-BUILD Probabilistic Demonstration
58
RESRAD-BUILD Probabilistic Demonstration
Use question 7 from deterministic workbook– Inhalation rate
– Removable fractions for all five sources
– Air release fractions for all five sources• Correlate?
Turn off Radon pathway to speed up calculations?
Verification of RESAD-BUILD
60
Internal Verification of RESRAD-BUILD
Published internal verification report October 2001
Compared RESRAD-BUILD calculations with those given in the users manual using MS Excel– Tritium model
– Radon model
– Direct ingestion
– Inhalation
– Indirect ingestion
Benchmarked external model with MCNP
61
Independent Verification of RESRAD-BUILD
Completed by Tetra Tech NUS Inc. March 2003
Provided verification of the: – Supporting radionuclide
database
– Input parameters
– Individual pathways
– Uncertainty Modules
Quality Assurance &
Quality Control
63
RESRAD-BUILD QA/QC Program
Changes to RESRAD-BUILD must be approved by the Project Leader and Program Manager
A modification must be reviewed by:– An independent scientist or programmer
– The Project Systems Analyst
– The Project Leader
– The Program Manager
All modifications are reviewed prior to release by all programmers
RESRAD-BUILD source code stored in Visual Source Safe to allowing for version control
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Thank You For Attending!!!!
E-mail: [email protected]
Web Site: http://www.evs.anl.gov/RESRAD