User’s Guide for 

RESRAD-OFFSITE 

Office of Nuclear Regulatory Research

NUREG/CR-7189

ANL/EVS/TM-14/2
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User’s Guide for 

RESRAD-OFFSITE

Manuscript Completed: September 2014

Date Published: April 2015

Prepared by:

E. K. Gnanapragasam

C. Yu

Argonne National Laboratory

9700 South Cass Avenue

Argonne, IL 60439

M. Fuhrmann, NRC Project Manager

NRC Job Code V6467

Office of Nuclear Regulatory Research

NUREG/CR-7189

ANL/EVS/TM-14/2

iii

ABSTRACT

The RESRAD-OFFSITE code can be used to model the radiological dose or risk to an offsite 

receptor. This User’s Guide for RESRAD-OFFSITE Version 3.1 is an update of the User’s Guide 

for RESRAD-OFFSITE Version 2 contained in the Appendix A of the User’s Manual for 

RESRAD-OFFSITE Version 2 (ANL/EVS/TM/07-1, DOE/HS-0005, NUREG/CR-6937). This 

user’s guide presents the basic information necessary to use Version 3.1 of the code. It also 

points to the help file and other documents that provide more detailed information about the 

inputs, the input forms and features/tools in the code; two of the features (overriding the source 

term and computing area factors) are discussed in the appendices to this guide. 

Section 2 describes how to download and install the code and then verify the installation of the 

code. Section 3 shows ways to navigate through the input screens to simulate various exposure 

scenarios and to view the results in graphics and text reports. Section 4 has screen shots of 

each input form in the code and provides basic information about each parameter to increase 

the user’s understanding of the code. Section 5 outlines the contents of all the text reports and 

the graphical output. It also describes the commands in the two output viewers. Section 6 deals 

with the probabilistic and sensitivity analysis tools available in the code. Section 7 details the 

various ways of obtaining help in the code. 

v

CONTENTS

ABSTRACT........................................................................................................................iii

CONTENTS......................................................................................................v

FIGURES.........................................................................................................ix

TABLES..........................................................................................................xv

1 INTRODUCTION.......................................................................................................1

1.1 Purpose Of User’s Guide ..................................................................................1

1.2 Organization Of User’s Guide ...........................................................................1

2 INSTALLATION........................................................................................................3

2.1 Installing From The RESRAD Website..............................................................3

2.2 Checking The Installation..................................................................................3

2.3 Uninstalling .......................................................................................................3

3 NAVIGATION............................................................................................................5

3.1 Menus and Toolbars .........................................................................................6

 3.1.1 Menus .....................................................................................................6

 3.1.2 Toolbars................................................................................................11

3.2 RESRAD DOS-Emulator.................................................................................12

3.3 Iconic Navigator Window.................................................................................13

3.4 Linked Input Forms .........................................................................................15

4 INPUT FORMS .......................................................................................................17

4.1 Title.................................................................................................................20

4.2 Preliminary Inputs ...........................................................................................23

4.3 Site Layout......................................................................................................25

4.4 Map Interface..................................................................................................27

4.5 Source (Initial Concentrations of Radionuclides at Site)..................................40

4.6 Source Release and Deposition Velocity.........................................................43

4.7 Distribution Coefficients ..................................................................................52

4.8 Transfer Factors..............................................................................................54

4.9 Set Pathways..................................................................................................56
vi

4.10 Reporting Times............................................................................................57

4.11 Storage Times...............................................................................................59

4.12 Physical and Hydrological Parameters..........................................................60

4.13 Primary Contamination (Contaminated Zone and Cover): Physical 

and Hydrological Data ..................................................................................62

4.14 Agricultural Areas and Livestock Feed Growing Areas: Physical 

and Hydrological Data ..................................................................................66

4.15 Offsite Dwelling Area: Physical and Hydrological Data..................................69

4.16 Atmospheric Transport Parameters...............................................................70

4.17 Unsaturated Zone Hydrology ........................................................................73

4.18 Saturated Zone Hydrology ............................................................................75

4.19 Water Use.....................................................................................................77

4.20 Surface Water Body......................................................................................79

4.21 Groundwater Transport Parameters..............................................................80

4.22 Ingestion Rates .............................................................................................84

4.23 Livestock Intakes (Factors) ...........................................................................86

4.24 Livestock Feed Factors and Plant Factors ....................................................87

4.25 Inhalation and External Gamma....................................................................88

4.26 External Radiation Shape and Area Factors .................................................90

4.27 Occupancy Factors .......................................................................................93

4.28 Radon Data...................................................................................................95

4.29 Carbon-14 Data ............................................................................................97

4.30 Tritium (H-3) Data .........................................................................................98

5 RESULTS ..........................................................................................................99

5.1 Report Viewer ...............................................................................................102

5.2 Graph Viewer (Deterministic and Sensitivity Analysis) .................................. 106

6 ENHANCEMENTS................................................................................................111

6.1 One-Parameter-at-a-Time Sensitivity Analysis.............................................. 111

6.2 Uncertainty and Probabilistic Analysis...........................................................114

 6.2.1 Parameter Distributions Tab ...............................................................117

 6.2.2 Sample Specifications Tab .................................................................119

 6.2.3 Input Rank Correlations Tab ...............................................................121

 6.2.4 Output Specifications Tab...................................................................122
vii

 6.2.5 Step-by-Step Analysis Tab..................................................................123

 6.2.6 Post Run Regression Tab...................................................................129

6.3 Multiparameter Sensitivity Analysis ...............................................................130

7 HELP.......... ........................................................................................................133

7.1 Application Help (on Input Parameters).........................................................134

7.2 Message Log ................................................................................................135

7.3 Website.........................................................................................................136

7.4 Run Time Feedback Form.............................................................................138

8 REFERENCES......................................................................................................139

APPENDIX A: Overriding the Source Term and Specifying Releases from Primary 

Contamination................................................................................... A-1

A.1 Nuclides with No Progeny ................................................................................. A-3

A.1.1 RESRAD-OFFSITE Source Module Output........................................... A-3

A.1.2 Checklist of Steps to Override the RESRAD-OFFSITE Source Model... A-9

A.2 Nuclides with Progeny in a Simple Transformation Chain ............................... A-16

A.3 Nuclides with Progeny in a Transformation Chain with Branches .................. A-20

A.4 Reference for Appendix A............................................................................... A-23

APPENDIX B: Computing Area Factors for Offsite Exposure Scenarios ................. B-1

B.1 Range of the X Dimension of the Small Area of Elevated Contamination.......... B-2

B.2 Range of the Y Dimension of the Small Area of Elevated Contamination.......... B-2

B.3 Distribution of the X and Y Dimensions of the Small Area of Elevated

 Contamination ................................................................................................... B-3

B.4 Location of the Center of the Small Area of Elevated Contamination ................ B-5

B.5 Number of Points on the Dose—Area Plot ........................................................ B-5

B.6 Generate Dimensions ....................................................................................... B-5

B.7 Generate Dose—Area Plot ............................................................................... B-6

B.8 Table of Area Factors........................................................................................ B-7

B.9 Reference for Appendix B............................................................................... B-16

ix

FIGURES

Figure 1. RESRAD-OFFSITE Interface ............................................................................5

Figure 2. Main Menu and Submenus ...............................................................................7

Figure 3. Primary Tool Bar ............................................................................................. 11

Figure 4. Pathways Toolbar ........................................................................................... 12

Figure 5. Sensitivity Analysis Summary Bar and Variable Information Toolbar............... 12

Figure 6. DOS-button Emulator...................................................................................... 13

Figure 7. Iconic Navigator .............................................................................................. 14

Figure 8. Title Form........................................................................................................ 20

Figure 9. Preliminary Inputs Form .................................................................................. 23

Figure 10. Site Layout Form........................................................................................... 25

Figure 11. The coordinate system used in RESRAD-OFFSITE...................................... 26

Figure 12. Map Interface ................................................................................................ 27

Figure 13. Map Interface File Dialog Form ..................................................................... 30

Figure 14. Setting the Scale in the Map Interface........................................................... 31

Figure 15. Locating and Sizing the Primary Contamination on the Map Interface........... 32

Figure 16. Locating and Sizing the Offsite icons on the Map Interface ........................... 33

Figure 17. Tracing a Groundwater flow line on the Map interface, first segment............. 34

Figure 18. Tracing a Groundwater flow line on the Map interface, last segment............. 35

Figure 19. Groundwater transport distances computed by Map Interface....................... 36

Figure 20. Fully Defined Map Interface........................................................................... 37

Figure 21. Site Layout Form........................................................................................... 38

Figure 22. Source Form ................................................................................................. 40

Figure 23. Source Release and Deposition Velocity Form ............................................. 43

Figure 24. Specifying Inputs for Version 2 Release Methodology................................... 44

Figure 25. Specifying Inputs for a First Order Rate Controlled Release with 

Transport....................................................................................................... 45

Figure 26. Specifying Inputs for a First Order Rate Controlled Release where the 

Radionuclide-Bearing Material Becomes Susceptible to Release Linearly 

over Time ...................................................................................................... 46

Figure 27. Specifying Inputs for a First Order Rate Controlled Release where the 

Radionuclide-Bearing Material Becomes Susceptible to Release Stepwise 

over Time ...................................................................................................... 47

Figure 28. Specifying Inputs for an Instantaneous Equilibrium Desorption Release ....... 48
x

Figure 29. Specifying Inputs for an Instantaneous Release where the 

Radionuclide-Bearing Material Becomes Susceptible to Release 

Linearly over Time......................................................................................... 49

Figure 30. Specifying Inputs for an Instantaneous Release where the 

Radionuclide-Bearing Material Becomes Susceptible to Release 

Stepwise over Time....................................................................................... 50

Figure 31. Distribution Coefficients Form for Version 2 Release..................................... 52

Figure 32. Distribution Coefficients Form for Version 3 Releases................................... 53

Figure 33. Transfer Factors Form................................................................................... 54

Figure 34. Transfer Factors Form for H-3 and C-14 ....................................................... 55

Figure 35. Set Pathways DOS-Emulator. ....................................................................... 56

Figure 36. Reporting Times Form................................................................................... 57

Figure 37. Storage Time Form ....................................................................................... 59

Figure 38. Physical and Hydrological Properties Form................................................... 60

Figure 39. Primary Contamination Form......................................................................... 62

Figure 40. Agricultural Area Form .................................................................................. 66

Figure 41. Livestock Feed Growing Areas Form ............................................................ 67

Figure 42. Offsite Dwelling Area Form ........................................................................... 69

Figure 43. Atmospheric Transport Form......................................................................... 70

Figure 44. Unsaturated Zone Hydrology Form ............................................................... 73

Figure 45. Saturated Zone Hydrology Form ................................................................... 75

Figure 46. Water Use Form............................................................................................ 77

Figure 47. Surface Water Body Form............................................................................. 79

Figure 48. Groundwater Transport Form........................................................................ 80

Figure 49. Ingestion Rates Form.................................................................................... 84

Figure 50. Livestock Intakes Form ................................................................................. 86

Figure 51. Plant Factors and Livestock Feed Factors Forms.......................................... 87

Figure 52. Inhalation and External Gamma Form........................................................... 88

Figure 53. External Radiation Shape and Area Factors Form ........................................ 90

Figure 54. Non-Rectangular Primary Contamination in External Radiation Shape 

and Area Factors Form.................................................................................. 91

Figure 55. Occupancy Factor Form................................................................................ 93

Figure 56. Radon Form.................................................................................................. 95

Figure 57. Carbon-14 and Carbon-12 Forms ................................................................. 97

Figure 58. Tritium Form.................................................................................................. 98

Figure 59. Report Viewer ............................................................................................. 102
xi

Figure 60. File Dialog box of Report Viewer................................................................. 103

Figure 61. Graph Viewer.............................................................................................. 106

Figure 62. Set Sensitivity Analysis Range Form........................................................... 111

Figure 63. Uncertainty and Probabilistic Analysis Form................................................ 114

Figure 64. Parameter Distributions Tab of the Uncertainty and Probabilistic 

Analysis Form ............................................................................................. 117

Figure 65. Help on Statistical Distributions Form.......................................................... 118

Figure 66. Sample Specification Tab of the Uncertainty and Probabilistic 

Analysis Form ............................................................................................ 119

Figure 67. Input Rank Correlations Tab of the Uncertainty and Probabilistic 

Analysis Form ............................................................................................. 121

Figure 68. Output Specifications Tab of the Uncertainty and Probabilistic 

Analysis Form ............................................................................................. 122

Figure 69. Step by Step Analysis Tab of the Uncertainty and Probabilistic 

Analysis Form ............................................................................................ 123

Figure 70. Step by Step Analysis Tab of the Uncertainty and Probabilistic Analysis 

Form when a Previously Executed Input File is Opened.............................. 124

Figure 71. The CDF of Output view of the Probabilistic/Uncertainty Graphics Output... 125

Figure 72. Scatter Plot of Output against Input view of the Probabilistic/Uncertainty 

Graphics Output .......................................................................................... 126

Figure 73. Scatter Plot of Output against Output view of the Probabilistic/Uncertainty

Graphics Output .......................................................................................... 127

Figure 74. Probabilistic Temporal Plots........................................................................ 128

Figure 75. Regression Analysis Tab of the Uncertainty and Probabilistic Analysis

Form ........................................................................................................... 129

Figure 76. Multi-Parameter Sensitivity Analysis View of Parameter Distributions

Tab of the Uncertainty and Probabilistic Analysis Form ............................... 130 

Figure 77. Regression Output ...................................................................................... 131

Figure 78. Output against Input Scatter plot Showing the Variation of Output with

One Input at Different Values of Another Input ............................................ 132

Figure 79. Context Sensitive Help................................................................................ 134 

Figure 80. Message Log Generated by the Computational Code ................................. 135 

Figure 81. RESRAD Website ....................................................................................... 136

Figure 82. A portion of the Documents Page of the RESRAD Website ........................ 137

Figure 83. Run Time Feedback Form........................................................................... 138
xii

Appendix Figures

Figure A.1 Examples of SFSIN.DAT and CZTHICK3.DAT Files Created by the 

Source Term Model of RESRAD-OFFSITE under the Traditional 

RESRAD Leach Model..............................................................................A-2

Figure A.2 Examples of AQFLUXIN.DAT, AIFLUXIN.DAT, and SWFLUXIN.DAT 

Files Created by the Source Term Model of RESRAD-OFFSITE 

under the Traditional RESRAD Leach Model.............................................A-3

Figure A.3 Temporal Profile of Activity in the Primary Contamination under the 

Traditional RESRAD First-Order Leach Rate Release Model ....................A-4

Figure A.4 Temporal Profile of Release to Groundwater under the Traditional 

RESRAD First-Order Leach Rate Model.................................................A-4

Figure A.5 Temporal Profile of Release to Atmosphere under the Traditional 

RESRAD First-Order Leach Rate Model ..................................................A-5

Figure A.6 Temporal Profile of Release to Surface Erosion under the Traditional 

RESRAD First-Order Leach Rate Model ...................................................A-5

Figure A.7 Temporal Profile of Release to Groundwater under the Equilibrium 

Desorption Release Model ........................................................................A-6

Figure A.8 Temporal Profile of Release to Groundwater under the First-Order 

Leach Rate with Transport Release Model................................................A-6

Figure A.9 Input Files AQFLUXIN.DAT, AIFLUXIN.DAT, and SWFLUXIN.DAT 

Created to Specify the Releases of This Example to 

RESRAD-OFFSITE..................................................................................A-9

Figure A.10 RESRAD-OFFSITE Input File Showing the Locations Where the 

Numbers of Time Points at which the Different Releases Are to Be 

Read Are Specified .................................................................................A-10

Figure A.11 Comparison of the Input Flux Specified in This Example Case for 

AQFLUXIN.DAT and the Flux Interpolated by RESRAD Using 

Different Numbers of Computational Time Points....................................A-11

Figure A.12 Comparison of the Input Flux Specified in This Example Case for 

AIFLUXIN.DAT and the Flux Interpolated by RESRAD Using 

Different Numbers of Computational Time Points....................................A-12

Figure A.13 Comparison of the Input Flux Specified in This Example Case for 

SWFLUXIN.DAT and the Flux Interpolated by RESRAD Using 

Different Numbers of Computational Time Points....................................A-13

Figure A.14 Automatic Selection of All Progeny with a Half-Life Greater Than the 

Cutoff Half-Life, When a Nuclide Is Specified To Be Initially Present 

in the Contamination ...............................................................................A-14

Figure A.15 Selection of Cutoff Half-Life.....................................................................A-16

Figure A.16 Source Term Output Files for Case with only 230Th Initially Present.........A-16
xiii

Figure A.17 Long-Lived Progeny Are at the Same Concentration as the Parent 

in the Initial Contamination ......................................................................A-17

Figure A.18 Source Term Output Files for Case in which 230Th and Its 

Long-Lived Progeny Are Initially Present.................................................A-18

Figure A.19 Progeny of 242mAm Modeled Explicitly by RESRAD-OFFSITE 

When a Cutoff Half-Life of 30 Days Is Specified ......................................A-19

Figure A.20 Chain File Generated by RESRAD-OFFSITE Showing the Branches 

and Threads of the 242mAm Transformation Chain ...................................A-20

Figure B.1 Area Factors Form—Default Options.........................................................B-2

Figure B.2 Area Factors Form—Option to Specify the Range of the Y Dimension 

of the Small Area of Elevated Contamination ............................................B-3

Figure B.3 Distribution of Area of the Small Area of Elevated Contamination under 

Three Distributions Options for Sampling the Dimensions of the Small 

Area of Elevated Contamination: Triangular Skewed to the High End, 

Uniform, and Triangular Skewed to the Low End.......................................B-4

Figure B.4 Area Factors Form—Generate Dose-Area Plot Command 

Button Activated ........................................................................................B-7

Figure B.5 Scatter Plot of Dose against Area of Contamination for Cs-137 

Where the Direct External Exposure from the Primary Contamination 

is the Dominant Pathway...........................................................................B-9

Figure B.6 Scatter Plot of Dose against Area of Contamination for Pu-239 for 

Which Atmospheric Transport Is the Dominant Route of Exposure .........B-10

Figure B.7 Scatter Plot of Dose against Area of Contamination for Tc-99 for 

Which Groundwater Transport Is the Dominant Route of Exposure.........B-11

Figure B.8 Sample of Area Factor Text Report for Cs-137........................................B-13

Figure B.9 Sample of Area Factor Text Report for Pu-239........................................B-14

Figure B.10 Sample of Area Factor Text Report for Tc-99..........................................B-15

TABLES

Table 1 Icon Identification. .......................................................................................... 28

Table A.1 Release to Be Input to RESRAD-OFFSITE....................................................A-8

1

1 INTRODUCTION

The RESRAD-OFFSITE code was initially developed to extend the capability of the RESRAD 

(onsite) code for modeling offsite receptor exposure scenarios (Yu et al. 2007). The transition 

from RESRAD (onsite) to RESRAD-OFFSITE, including benchmarking of RESRAD-OFFSITE 

code against peer codes, was documented in DOE/EH-0708 (Yu et al. 2006). The capability of 

RESRAD-OFFSITE code was further enhanced in the modeling of the source release term for 

handling containerized waste materials. This new source term model was documented in 

NUREG/CR-7127 (Yu et al. 2013) for potential application to low-level radioactive waste 

disposal facility performance assessment. A new version of RESRAD-OFFSITE (Version 3.1) 

was released following the incorporation of this new source term model. Version 3.1 includes 

additional features such as time-distributed source release and computation of area factors for 

offsite exposure scenarios.

1.1 Purpose Of User’s Guide

The primary purpose of this user’s guide is to help users understand and use the RESRADOFFSITE code Version 3.1. It describes how to download and install the code, as well as how to 

navigate through the input screens to simulate various exposure scenarios and view the results 

in graphics and text reports. This user’s guide not only describes the features of RESRADOFFSITE, Version 3.1, it also provides additional information about the input parameters to 

increase the user’s understanding of the code. Some advanced features, such as overriding the 

source term model, use of probabilistic and sensitivity analysis, and computing the area factors, 

are also included in this user’s guide.

1.2 Organization Of User’s Guide 

This information is organized into the following major sections:

• Section 2. Installation: Installation procedures and system requirements.

• Section 3. Navigation: Instructions for moving around the interface to 

accomplish various tasks and to save input and output.

• Section 4. Input forms: Description of each input form, information on how to 

use each form, and parameters in the input forms.

• Section 5. Outputs: Instructions on how to find results in the textual and 

graphical output.

• Section 6. Enhancements: Explanation of the probabilistic/uncertainty 

analysis and sensitivity analysis features.

• Section 7. Help: Various ways of obtaining help.

• Section 8. References: List of references.

• Appendix A. Overriding the source term module: Description of how to 

override the source and release module of the computational code, as well as 

how to specify temporal information about the primary contamination and the 

release.

• Appendix B. Computing the area factors: Description of a menu option that 

facilitates the calculation of area factors of small areas with elevated 

contamination for offsite exposure scenarios.

3

2 INSTALLATION

The RESRAD family of codes, including RESRAD-OFFSITE, Version 3.1, is distributed through 

the RESRAD Website (http://www.evs.anl.gov/resrad). The code requires a Windows XP or 

later operating system and about 100 MB of disk space. The code has been tested and is fully 

compatible with the Windows 7 operating system. The procedure for downloading and installing 

RESRAD-OFFSITE code is described in Section 2.1, the procedure for checking the installation 

is outlined in Section 2.2, and the procedure for uninstalling RESRAD-OFFSITE code is 

described in Section 2.3.

2.1 Installing From the RESRAD Website

1. Connect to the RESRAD Website at http://www.evs.anl.gov/resrad.

2. Click on “Download Codes”.

3. Fill in the requested information and download the installation program.

4. When the installation program launches, enter the information requested by 

the standard installation program.

5. If the default installation selections are used, the files needed to execute 

RESRAD-OFFSITE version 3.1 will be installed in

C:\RESRAD_Family\OFFSITE\3.1\.

The installation would also have created the following subdirectories:

..\Metfiles\: The STAR format meteorological files will be installed here. 

..\Userfiles: The input and output files are saved in this directory. 

..\QAfiles\: The QA files from the RESRAD Website can be copied here.

6. After installation, a new RESRAD-OFFSITE icon will appear on the computer 

desktop. Double-click this icon to start RESRAD-OFFSITE.

2.2 Checking the Installation

1. Connect to the RESRAD Website at http://www.evs.anl.gov/resrad. 

2. Click on “User Center”.

3. Save the QA_RESRAD_OFFSITE_3.1.zip file to the QA subdirectory.

4. Follow the instructions in the ReadMe file, which is in the zip file.

2.3 Uninstalling

1. Use Uninstall, a program utility in the Windows control panel.

5

3 NAVIGATION

Four independent methods are available to access information through the RESRAD-OFFSITE 

interface (Figure 1):

Figure 1. RESRAD-OFFSITE Interface

1. Menu and Toolbars: These are the standard Windows tools used to 

manipulate files, input forms (i.e., screens), and output forms; shortcut keys 

are included for advanced users. These are described in Section 3.1.

2. Linked Input Forms: All relevant input forms are linked together by two 

buttons in each input form; these buttons save the data in that input form and 

then open either the next input form or the previous one (Section 3.4). Start 

by pressing the “New user, Chain through all Input Screens” button in the 

About RESRAD-OFFSITE popup window that displays upon starting 

RESRAD-OFFSITE. The About screen can also be accessed via the Help 

menu [press Alt-H, then press A]. 
6

3. RESRAD DOS-Emulator: This set of textual command buttons is similar to 

the buttons used in RESRAD for the DOS interface (Section 3.2).

4. Iconic Navigator Window: This tabbed window provides access to the 

information through more graphical cues (Section 3.3).

3.1 Menus and Toolbars

3.1.1 Menus

The menu on the main RESRAD-OFFSITE window (i.e., the Main Menu) gives complete access 

to all the forms, functions, and features of the code. The Main Menu and the submenus that 

branch from it are shown below (Figure 2).
7

Figure 2. Main Menu and Submenus
8

The menu operations can be performed by clicking the mouse, by pressing the hot (underlined) 

keys after activating them with the Alt key, or by using the shortcut keys shown next to the 

submenu commands.

File Submenu: The first block of four commands performs common file operations. The next 

two commands facilitate the modeling of onsite scenarios. The remaining five commands can 

be used to access the Title window, to perform an analysis using the current inputs, to initiate 

the process of generating area factors, to generate all the files that are necessary to execute the 

computational code in batch mode (Generate files for batch mode execution), or to launch the 

Dose Conversion Factor Editor (DCF Editor).

• New: This starts afresh with a set of default or placeholder values for all the 

parameters.

• Open: This brings up the dialogue box to open a previously saved input file. 

• Save: This saves the current input file.

• Save As: This brings up the dialogue box to save the current inputs under a 

different filename.

• Onsite Scenario Template File: This menu provides a starting point to use 

the RESRAD-OFFSITE methodology to model an onsite exposure scenario. 

The interface is reset as follows when this menu command is clicked: (1) all 

the agricultural areas are placed on top of the primary contamination; (2) the 

surface water body and the well are placed at the down-gradient edge of the 

primary contamination and the dispersivities in the saturated zone are 

adjusted accordingly; (3) the wind speed, the well pumping rate, the fractions

of meat and milk from the affected area, and the onsite dwelling occupancies 

(indoor and outdoor) are set to the RESRAD default values; (4) the 

occupancies in the agricultural areas are set to add up to the RESRAD 

default outdoor occupancy, and the offsite dwelling occupancies are set to 

zero; and (5) the volume of surface water body is set to a value that will yield 

surface water results similar to RESRAD. All the inputs (including the offsite 

ones) remain enabled so that the user may take advantage of all the 

processes modeled by RESRAD-OFFSITE.

• Simulate RESRAD (onsite) Code: This command mimics the RESRAD 

(onsite) code to the extent possible by resetting the interface as follows:

(1) all the agricultural areas are placed on top of the primary contamination; 

(2) the surface water body and the well are placed at the down-gradient edge 

of the primary contamination; (3) the wind speed, the erosion rates of the 

cover and primary contamination, the well pumping rate, the fractions of meat 

and milk from the affected area, and the onsite dwelling occupancies (indoor 

and outdoor) are set to the RESRAD default values; (4) the dispersivities in 

the groundwater transport zones, the sediment delivery ratio, the 

occupancies in the agricultural areas are set to zero; (5) the volume of 

surface water body is set to a value that will yield surface water results similar 

to RESRAD; and (6) the shape of the primary contamination is treated as a 

circle for direct external radiation calculations. The inputs that are common 

with RESRAD remain enabled; most of the others are disabled and are set to 

the values of the corresponding values in RESRAD. 

• Title: This displays the Title form.

• Run RESRAD-OFFSITE: This command saves the input file, generates all 

the data files that are necessary to execute the computational code, and 

launches the computational code. 
9

• Generate Area Factors: This initiates the process of generating area factors. 

The process of generating area factors is summarized in Appendix B of this

user’s guide and is discussed in greater detail in Appendix E of 

NUREG/CR-7127.

• Generate Files for Batch Mode Execution: This command saves the input 

file and generates all the data files that are necessary to execute the 

computational code, but does not launch the computational code.

• DCF Editor: This launches the Dose Conversion Factor Editor.

Pathways Submenu: This is used to activate, deactivate, or verify the status of each exposure 

pathway. A checkmark next to a pathway indicates that it is currently active.

Site Data Submenu: All but four of the forms that are needed to specify the situation to be 

modeled are directly accessible from this submenu. The shape and area factor form for external 

radiation is accessible from the inhalation and external gamma form, and the nuclide-dependent 

property forms (the source release and atmospheric transport form, the distribution coefficients 

form and the transfer factors form) are accessible after the nuclides have been selected from 

the source form. Any forms that are currently open (i.e., being displayed) are indicated by a 

checkmark on the submenu.

View Submenu: This submenu has two functions: it provides access to the various output 

windows, and it is used to set the display options for a number of features of the code. The first 

two subgroups display the textural and graphical outputs of a RESRAD-OFFSITE analysis, 

which are discussed in Section 5. The last group of commands on this submenu is used to set 

the user’s preference to display (indicated by a checkmark) or hide (no checkmark) the following 

functions of the code:

• Iconic Navigator: This is the Iconic Navigator window, which can also be 

used to access the forms, to perform the analysis and to view the output. This 

is discussed in Section 3.3.

• Tool Bar: This is the primary toolbar, shown in Section 3.1.2.

• Pathway Bar: This is the pathways toolbar, shown in Section 3.1.2.

• Sensitivity Input Summary: This is the sensitivity analysis (one parameter 

at a time) information bar, shown in Section 3.1.2.

• Uncertainty/Probabilistic Interface: This form, which details any 

probabilistic analysis that is to be performed for the current input file, is 

discussed in Section 6.2. This form can also be used to perform step-by-step 

probabilistic analysis and to view plots of the results.

• Map Interface: This is the form that displays the plan view of the locations of 

the primary and secondary contamination. Section 4.4 describes the map 

interface. Unlike in the other cases where the user’s preference is a simple 

show or hide, there are three possibilities in this case. The user may indicate 

a preference to see the map only when the site layout form is displayed in the 

sequence of forms (to set this, set the preference to view map while the 

layout form is displayed), to see the map at all times (to set this, set the 

preference to view map when the layout form is not being displayed), or to 

never see the map.

• Soil Strata Graphics: This is a sketch of the cross-section of the ground 

below the primary contamination.
10

• Button Prompts: A button prompt is a short descriptive name for a control 

on the toolbar or on the Pathways/Inputs tab of the Iconic Navigator window.

A prompt is displayed when the mouse cursor moves over the control and 

lingers there for a short while. The descriptions of the objects in the map 

interface are also displayed as the mouse lingers over the different objects in 

the map interface.

• Variable Information: This is the variable information bar, shown in 

Section 3.1.2.

Form Options Submenu: The first two commands on the Form Options submenu, Save 

current form and Cancel current form, are used to save or cancel the changes made to an open 

form (Section 4). The remaining six commands perform operations on the input boxes contained 

in the forms, as follows:

• Sensitivity Analysis (single parameter): This is used to activate “one 

parameter at a time sensitivity analysis” (Section 6.1) on the input parameter 

and to set the range of the parameter for the analysis.

• Uncertainty/Probabilistic Analysis: This is used to include the input 

parameter in the probabilistic or uncertainty analysis (Section 6.2). It can also 

be used to display the uncertainty/probabilistic analysis form if it is not visible.

• Multi-parameter Sensitivity Analysis: This is used to include the input 

parameter in the probabilistic or uncertainty analysis with uniform or loguniform distribution of a selectable range about its current value and to 

display the uncertainty/probabilistic analysis form if it is not visible.

• Lower Bound: This is used to set the input to the lowest value accepted by 

RESRAD-OFFSITE. The lowest value may be a physical bound (i.e., the 

lowest value that is applicable for the parameter because of physical 

considerations) or simply a numerical bound imposed to prevent the code 

from crashing.

• Default: This is used to set the input to the default value assigned in the 

RESRAD-OFFSITE code. While some default values (e.g., ingestion rates, 

inhalation rates) are generally accepted values, others (e.g., field capacity, 

distribution coefficient) are merely placeholder values.

• Upper Bound: This is used to set the input to the highest value accepted by 

RESRAD-OFFSITE. The highest value may be a physical bound (i.e., the 

highest value that is applicable for the parameter because of physical 

considerations) or simply a numerical bound imposed to prevent the code 

from crashing.

Help submenu: This is used to obtain context-sensitive information about the inputs, forms,

and features in RESRAD-OFFSITE; to access PDF versions of this user’s guide and the user’s

technical manual; and to display the About RESRAD-OFFSITE form.

• Context-Sensitive Help: Information about a specific input parameter, form,

or feature in RESRAD-OFFSITE can be obtained by pressing the F1 function 

key while the input control is in focus (box, option buttons, dropdown box, 

etc.). The input control is in focus when the cursor is in the field of the control.

• User’s Guide: This opens the PDF version of this document.

• User’s Technical Manual: This opens the PDF version of the user’s manual.
11

• NUREG/CR-7127: This opens the PDF version of NUREG/CR-7127, which 

deals with the source release options added to Version 3.1 of 

RESRAD-OFFSITE and with performing sensitivity analysis.

• About RESRAD-OFFSITE: This displays the About RESRAD-OFFSITE form 

(i.e., the About form). This form shows the version and release date of the 

RESRAD-OFFSITE software installed on the computer, the amount of 

physical memory that is available on the computer, and the e-mail contact for 

the RESRAD team; it also provides a link to access the RESRAD Website.

3.1.2 Toolbars

Primary Toolbar

The primary toolbar below (Figure 3) is displayed if the user preference is set to display it in the 

View submenu (Section 3.1.1) (the default is to show this toolbar). The operations that can be 

performed by clicking on the icons on the primary toolbar are shown below. If the Button 

Prompts option was selected from the View submenu on the Main Menu, a message prompt 

appears as the cursor lingers over an icon to display what the icon means.

 Files Input Results Display Feedback RESRAD

Figure 3. Primary Tool Bar

• Files

− Reset all input parameters to default values

− Open an existing input file

− Save data currently in all input forms to a file

• Input

− Perform calculations

− Save changes to current input form

− Cancel changes to current input form

− Display/hide sensitivity analysis input form

− Display/hide uncertainty analysis input form

• Results

− View summary report

− View deterministic graphics

− View uncertainty/probabilistic graphics

• Display Feedback

− Display/hide soil strata graphics

− Display/hide pathway button bar

− Display/hide variables for sensitivity analysis

• RESRAD—Simulate RESRAD (onsite) code
12

Pathways Toolbar

The pathways toolbar below (Figure 4) is displayed if the user preference is set to display it in 

the View submenu (Section 3.1.1) (the default is to hide this toolbar). The pathways toolbar is 

used to toggle between active and inactive for each pathway, and it displays the status of the 

pathways.

Figure 4. Pathways Toolbar

Sensitivity Analysis Input Summary Bar

The sensitivity analysis input summary bar (shown in the upper half of Figure 5 below) is 

displayed if the user preference is set to display it in the View submenu (Section 3.1.1) (the 

default is to show this interactive summary bar). It shows the number of variables selected for 

one-parameter-at-a-time sensitivity analysis (Section 6.1) and contains a button for each of 

those variables. The buttons display the FORTRAN variable name and the range factor for the 

sensitivity analysis on the variable. Left-click the mouse with the cursor on the sensitivity button 

to access the Sensitivity Analysis form for the variable. Right-click the mouse with the cursor on 

the sensitivity button to remove that variable from sensitivity analysis. The height of the bar 

depends on the number of variables selected for sensitivity analysis and should not be adjusted 

by the user.

Figure 5. Sensitivity Analysis Summary Bar and Variable Information Toolbar

Variable Information Bar

The variable information bar (shown in the lower half of Figure 5 above) is displayed if the user 

preference is set to display it in the View submenu (Section 3.1.1) (the default is to show this 

information bar). This bar displays information (FORTRAN name, default, and bounds) about 

the current input.

3.2 RESRAD DOS-Emulator

All applicable input fields can be accessed by following the command buttons in the RESRAD 

DOS-Emulator found on the left side of the interface. Some of the command buttons are linked 

directly to forms, while other commands lead to a group of second-level commands that appear 

to the right of the primary command list. All the buttons (Figure 6) can be followed sequentially 

except for the Radon pathway button; it can be turned on only after a radon precursor has been 

selected from the Source form. The forms that are linked to these command buttons are 

discussed in Section 4. 
13

Figure 6. DOS-button Emulator

If the screen resolution is not sufficient to display the expanded modify data command buttons 

(1024 × 768 pixels), a compact version can be displayed by clicking on the “Hide Subscreens” 

command button.

3.3 Iconic Navigator Window

The Iconic Navigator window (Figure 7) will be displayed if that user preference has been set 

using the View submenu (the default preference is to display this window). It has four tabs. The 

first tab, Problem, gives the broad outline of the sequence to be adopted to perform the 

analysis. Buttons on the tab lead to the second tab, Pathways/Input, which is for specifying the 

site-specific scenario being analyzed, and to the third tab, Results, for viewing the results. The 

forms that are accessed by these buttons are described in Section 1.3. Prompts displaying a 
14

descriptive name will appear as the cursor lingers over the buttons on the Pathways/Input tab.

This feature is turned on using the Button Prompts option from the View submenu (prompts are 

displayed by default).

Figure 7. Iconic Navigator
15

• Problem: This tab guides the user to set up a case in RESRAD-OFFSITE.

Each button brings up windows or forms to continue with the process. 

• Pathways/Input: This tab allows the user to view and activate pathways.

Buttons for the pathways can be found in the three black boxes. Inhalation 

pathways are above the person, and ingestion pathways are to the left. The 

single external pathway is at the lower right. Input windows are accessed by 

clicking on icons. Prompts appear to display what the icon means if the 

Button Prompts option was selected from the View submenu.

• Results: The top two buttons give access to the main deterministic results in 

report and graphical formats. The next two buttons open supplementary 

reports. If an uncertainty analysis was run, three more buttons below the 

purple line to provide access to the two reports and a set of graphics.

• Help: If the user operating system is connected to the Internet, this tab gives 

the user access to the RESRAD Website and provides the address to which 

users can e-mail questions for the RESRAD team.

3.4 Linked Input Forms

All the input forms that are relevant to the current analysis can be displayed in sequence by 

using the forward and backward arrows in each form. The linked sequence begins in the About 

RESRAD-OFFSITE window, which is displayed every time RESRAD-OFFSITE is launched.

This window is also accessible from the Help submenu (press Alt-H, then press A). The last 

form in the sequence has the run command instead of a forward arrow; it issues the command 

to perform the RESRAD-OFFSITE analysis using the current set of inputs. The sequence of the 

forms is as follows: Title, Preliminary Inputs, Site Layout (and map interface), Source, Source 

Release and Deposition Velocity, Distribution Coefficients, Transfer Factors, Set Pathways, 

Reporting Times, Storage Times, Physical and Hydrological, Primary Contamination, 

Agricultural Areas, Livestock Feed Growing Areas, Offsite Dwelling Area, Atmospheric 

Transport, Unsaturated Zone Hydrology, Saturated Zone Hydrology, Water Use, Surface Water 

Body, Groundwater Transport, Ingestion Rates, Livestock Intakes, Livestock Feed Factors, 

Plant Factors, Inhalation and External Gamma, External Radiation Shape and Area Factors, 

Occupancy, Radon, Carbon-14, Mass Fractions of Carbon-12, and Tritium. The last four forms 

are displayed only if they are relevant to the current selection of nuclides. The forms are 

described in the linked sequence in Section 4.

17

4 INPUT FORMS

There are more than 30 input forms for entering the parameters that define the site data, 

assumptions, site identification, and calculation specifications. Sections 4.1 through 4.30

describe each form in detail and have a description of each input on the form. Additional 

information about each input can also be obtained by clicking the help command, F1, when the 

cursor is in that input field. The RESRAD-OFFSITE predictions of dose and risk, dependent on 

the values specified for the inputs on these forms. The sensitivity of the predictions to the value 

of an input depends on the scenario being considered and the values of the other inputs. Hence 

it is imperative that site-specific or site-appropriate values be used for all the inputs except for 

those that are defined by the standard receptor. Most input is entered by keying numbers into 

boxes, but some input is entered through list boxes, check boxes, and option boxes. Some 

features common to all input forms are described here.

Saving Information to Memory

There are two levels at which information can be saved in RESRAD-OFFSITE. The first level is 

to temporarily save the information to memory. This can be done with any of the following 

commands:

• Command Buttons: Click on the Save button, Forward button, or Backward 

button on the form.

• Menu: Select Form Options, then Save current form (Ctrl-K).

• Toolbar: Click on the Folder button.

Saving Information to File

The second level is to save the settings to a file. This can be done with any of the following 

commands:

• DOS-Emulator: Press the File button on the DOS-Emulator to activate the 

File Options form. Then select Save or Save As.

• Menu: Select File, then either Save (Ctrl-S) or Save As (Ctrl-A).

• Toolbar: Press the Disk button to save to a file.

• Run: If any input form was exited with a save operation (as opposed to a 

cancel operation), then the file will need to be saved to disk before 

calculations are performed. This will perform a save, but not a save as.

Canceling Changes Made to a Form

The changes to the inputs in a form can be canceled if they have not yet been saved to 

memory. 

• Function Keys: Press the Esc key.
18

• Command button: Click on the Cancel button on the form.

• Menu: Select Form Options, then Cancel current form (Ctrl-U).

• Toolbar: Click on the Canceled Folder button.

Saving Information to Memory and Opening Next or Previous Form

The information in a form can be saved to memory, and the next or previous form can be 

opened by pressing the forward arrow or the backward arrow on each form, as appropriate. 

Entering Numbers

Some input boxes may be grayed out (disabled) because they are not applicable 

to the current case, either because some pathways have been turned off or because the 

pertinent radionuclide was not chosen. Values representative of the site should be entered in all 

input boxes that are active.

The default value and the bounds (upper and lower) of the selected parameter will be displayed 

in the variable information bar. The value in the input box may be set to the default value or to 

an upper or lower bound, as described below.

• Defaults: To set the selected parameter to its default, either select Form 

Options and then Default from the Main Menu, or press the F6 function key.

While some default values (e.g., ingestion rates, inhalation rates) are 

generally accepted values, others (e.g., field capacity, distribution coefficient) 

are merely placeholder values.

• Bounds: To set the selected parameter to its upper (or lower) bound, either 

select Form Options and then UpperBound (or LowerBound) from the Main 

menu, or press the F7 (F5) function key. These may be a physical bound 

(i.e., the highest or lowest value that is applicable for the parameter because 

of physical considerations) or simply a numerical bound imposed to prevent 

the code from crashing.

Obtaining Help

Context-specific help will be shown anytime the F1 function key is pressed. For additional 

sources of help, please refer to the Help section (Section 7) of this user’s guide. 

Selecting a Parameter for Probabilistic or Uncertainty Analysis

Input parameters can be selected for inclusion in a probabilistic or uncertainty analysis by 

pressing the F8 key while the cursor is in the input box for that parameter (see Section 6.2,

Uncertainty and Probabilistic Analysis). Some parameters are ineligible for uncertainty analysis, 

either because it does not make sense to perform the analysis on those parameters, or because 

of the unmanageable constraints imposed by interrelationships with other parameters.
19

Selecting a Parameter for One-Parameter-at-a-Time Sensitivity Analysis

Input parameters can be selected for one-parameter-at-a-time sensitivity analysis by pressing 

the F9 key while the cursor is in the input box for that parameter (see Section 6.1, Sensitivity 

Analysis). Some parameters are ineligible for sensitivity analysis because it does not make 

sense to perform a sensitivity analysis on those parameters.

Selecting a Parameter for Multi-parameter Sensitivity Analysis

Input parameters can be selected for inclusion in a multi parameter sensitivity analysis by 

pressing Shift-F8 while the cursor is in the input box for that parameter. The selected 

parameters can have a uniform distribution with a half range of 50%, 25%, 10%, 5%, or 0.1% of 

the deterministic value on either side of the deterministic value, or a log-uniform distribution 

ranging from 1/10 to 10, 1/5 to 5, 1/3 to 3, 1/2 to 2, or 1/1.001 to 1.001 times the deterministic 

value (see Section 6.2, Uncertainty and Probabilistic Analysis). Only the parameters that are 

eligible for uncertainty analysis can be included in the Multi-parameter Sensitivity Analysis. The 

sensitive parameters can be ranked using the standardized regression coefficient or the 

standardized rank regression coefficient. Multi-parameter Sensitivity Analysis is discussed in 

section 6.3 of this guide.
20

4.1 Title

Figure 8. Title Form

The title form (Figure 8) does not have a cancel feature. Any changes made to this form can be 

reversed only by re-inputting the original inputs. None of the parameters in this form are eligible 

for uncertainty analysis or for one-at-a-time sensitivity analysis.

Title: This box shows the text that describes the site/scenario being modeled. This identification 

text will appear at the top of each textural report page. Note that the apostrophe character (‘) 

cannot be used in the Title field or the code will crash.

Location of Dose, Slope, and Transfer Factor Database Library: This is the directory in 

which the RESRAD dose, slope, and transfer factor database and editor are located. A common 

dose, slope, and transfer factor database can be used by many of the RESRAD codes 

(RESRAD [onsite], RESRAD-BUILD, RESRAD-OFFSITE), which makes any user-created 

library accessible to all the codes. Therefore, the database file need not reside in the OFFSITE 

directory; instead, it can be in a directory that is shared by the RESRAD family of codes. 

Double-click on this input box to activate a file dialog form, then navigate to the directory in 

which the database that you want to use is located. Open the database you want to use, and 

the libraries available in that database will be displayed in the appropriate drop-down lists.
21

External Exposure Library and the Inhalation and Ingestion Dose Library: The dose 

conversion factors in these libraries will be used for the current analysis. Libraries of dose 

conversion factors can be set up by using the RESRAD Dose Conversion Factors Editor, which 

is a standalone utility program common to the RESRAD family of codes. The libraries are stored 

in a database file. The second drop-down list contains all the internal exposure dose conversion 

factor libraries that are available in the current database; these include the standard RESRAD 

FGR11 (Eckerman et al. 1988) and age-dependent ICRP72 (ICRP 1996) libraries and any 

libraries created by the user. The library displayed in the first drop-down box for external 

exposure depends on the library chosen in the second drop-down box for internal exposure. If 

the ICRP 30 based internal exposure library, FGR 11, is chosen, then the external exposure 

dose factors will be from FGR 12. The external exposure dose factors will be from ICRP 60 if an 

ICRP60-based age-dependent internal dose library from ICRP72 is chosen. Both the internal 

and external exposure dose factors will come from the user-created library when a user-created 

library is selected.

Slope Factor Library: The slope factors (risk) in this library will be used for the current 

analysis. Libraries of slope factors can be set up by using the RESRAD Dose Conversion 

Factors Editor, which is a standalone utility program common to the RESRAD family of codes.

The libraries are stored in a database file. The drop-down list contains all the slope-factor 

libraries that are available in the current database: the standard RESRAD FGR13 morbidity

(Eckerman et al. 1999), FGR13 mortality, the HEAST2001 morbidity libraries (EPA 2001), and 

any created by the user.

Transfer Factor Library: The transfer factors in this library will be used for the current analysis 

unless the values are changed in the nuclide-specific transfer factor form (Section 4.8). Libraries 

of transfer factors can be set up using the RESRAD Dose Conversion Factors Editor, which is a 

standalone utility program common to the RESRAD family of codes. The libraries are stored in a 

database file. The drop-down list contains all the dose conversion factor libraries that are 

available in the current database, including the standard RESRAD default transfer factor library 

and any libraries created by the user. The RESRAD transfer factor library contains only one soilto-plant transfer factor for each nuclide, whereas the RESRAD-OFFSITE code can accept and 

use different factors for the vegetation in each of the four different agricultural and farmed areas.

The transfer factors are site and species specific; the transfer factor form (Section 4.8) allows 

these values to be changed for each input file without having to create a different library for 

each site.

Cutoff Half-Life: The fate and transport of nuclides with half-lives larger than the specified halflife are modeled explicitly by the code. Progeny nuclides with a half-life shorter than the 

specified value are assumed to be in secular equilibrium with their immediate parent. The user 

can select from the values in the list (180, 30, 7, or 1 day[s]) or type in any value that is not less 

than 10 minutes. Only the nuclides that have a half-life greater than the cutoff half-life are listed 

in the right scroll box on the Source form.

Informational Boxes: There are two informational boxes in this form. The first shows the 

number of radionuclides in the current ICRP38 (ICRP 1983) database that have a half-life 

greater than or equal to the current cutoff half-life. The second shows the number of such 

nuclides that are lacking at one or more dose conversion or slope factors.
22

Intermediate Time Points

• Number of Points: This shows the number of time points at which 

concentrations, doses, and risks are computed. Because RESRAD-OFFSITE 

can compute concentration and flux at any time on the basis of the 

concentrations and fluxes computed at preceding times, and because the 

code uses all the time points that fall within the appropriate exposure duration 

to perform time integration of dose and risk, this parameter determines the 

accuracy of the computed values. The number of points in the temporal 

graphics will be set to this number. Straight line segments connect the points 

in the curve. A larger number of times enables the code to compute offsite 

accumulation, groundwater transport, and time integration of dose and risk 

more accurately and will result in smoother plots. However, a larger number 

will also increase the execution time. For most radionuclides, a number of 

time points equal to about one-tenth to one-fifth of the prediction time horizon 

should give results of sufficient accuracy. A greater number of intermediate 

time points are required if the rate of release of a radionuclide changes 

rapidly over time. The number of points shown must be such that a linear 

approximation between the values of flux at those times is a good 

representation of the actual temporal variation of the flux. The interval of time 

between the intermediate time points must also not exceed the travel time in 

any of the groundwater transport zones.

• Linear Spacing or Log Spacing: The spacing shows the manner in which 

the intermediate time points are distributed over the time horizon. The time 

horizon is the sum of the maximum user-specified reporting time 

(Section 4.10, Reporting Times) and the exposure duration (Section 4.2, 

Preliminary Inputs). The spacing may be linear or log.

1. Linear: If linear is chosen, the intermediate time points are spaced 

uniformly (in an arithmetic sequence) between 0 and the time horizon.

2. Log: If log is chosen, the intermediate time points are spaced in a 

geometric sequence (uniformly on a logarithmic scale) between the 

specified minimum time increment and the time horizon. The spacing in 

this case may be adjusted by the minimum time increment, as described 

below.

• Minimum Time Increment: In addition to being the first intermediate time 

point under the choice of log spacing, as described above, this is also the 

lower bound for spacing between intermediate time points of a geometric 

sequence. Depending on the time horizon and the number of points, the 

spacing between the intermediate time points can be very small at the 

beginning of the geometric sequence. In order to avoid unnecessary 

calculations, if the spacing is less than the specified minimum value, the 

sequence of time points will then be modified to a linear sequence with the 

minimum time increment, followed by a geometric sequence with a time 

increment that is never less than the specified minimum.

Update Progress of Computation Message: The time needed to perform the RESRADOFFSITE computations can range from a few minutes to a couple of hours, depending on the 

number of intermediate time points, number of radionuclides, number and lengths of 
23

transformation chains, groundwater transport characteristics of the nuclides, and, in the case of 

probabilistic analysis, number of realizations that are chosen. The FORTRAN computational 

code periodically writes out a message indicating the progress of the computation to reassure 

the user that computations are being performed and, in the case of probabilistic analysis, to 

provide an estimate of the time required to finish the computations. This input box specifies the 

frequency at which this message will be updated by the computational code and the frequency 

at which it is sampled for display in the interface.

Writing the progress message can increase the total run time significantly. A “0.0" option is 

provided to turn off message writing by computational code. This can reduce the run time of 

probabilistic analysis. In this case, an estimate of the computation time will be made based on 

the size of the output files.

Use Line Draw Character: MS LineDraw Font is recommended for use in the reports. This font 

produces well-formatted tables and lines. If another font is desired, it is suggested that this box 

be unchecked to substitute minus signs for the lines.

Forward Arrow Button: Save the current values, hide the Title form, and open the next form 

(Section 4.2, Preliminary Inputs), all with one click of this button (or Alt-O). The same button 

appears on all input forms to facilitate rapid movement through all the relevant input forms.

OK Button: Use this button to hide (i.e., minimize away from view) the Title form.

4.2 Preliminary Inputs

Figure 9. Preliminary Inputs Form
24

The preliminary inputs form (Figure 9) allows selection of dose units, the default release 

mechanism and other parameters that determine the appearance of other input forms. It also 

contains the two inputs which do not belong in any of the other input forms. None of the 

parameters in this form are eligible for uncertainty analysis or for one-at-a-time sensitivity 

analysis.

Radiological Units

• Activity: The drop-down boxes allow the user to choose the desired unit of 

radiological activity. Available choices are curie (Ci), becquerel (Bq), 

disintegrations per second (dps), and disintegrations per minute (dpm); the 

first two can be combined with metric prefixes ranging from atto (10-18) 

through exa (1018).

• Dose: The drop-down boxes allow the user to choose the desired unit of 

radiological dose. Available choices are roentgen equivalent man (rem) and 

sievert (Sv); these can be combined with metric prefixes ranging from atto 

(10-18) through exa (1018).

Basic Radiation Dose Limit: This is the annual radiation dose limit used to derive all sitespecific soil guidelines.

Exposure Duration: This is the length of time that the receptor is exposed to radiation at this 

site. Values reported for risk are time-integrated over this exposure duration. The risk is 

calculated by using the trapezoidal formula on contaminated intakes computed at all the 

intermediate time points falling within the exposure duration and at the intermediate time point 

that is just outside the exposure duration. Dose is time integrated over 1 year or the exposure 

duration, whichever is less. (Given the current lower bound of 1 year on the exposure duration, 

dose is currently integrated over a 1-year period.)

Number of Unsaturated Zones: This is the number of partially saturated layers between the 

primary contamination and the saturated zone. The code has provisions for up to five different 

horizontal strata.

Default Release Mechanism: Two additional release mechanisms were introduced in 

Version 3.1. These release mechanisms are discussed in Section 4.6. The default mechanism 

specified in this form when a nuclide is selected for analysis will be used as the release 

mechanism for that nuclide. Changing the release mechanism for each nuclide after adding all 

the nuclides is tedious. If a file contains many nuclides it would be more convenient for the user 

to specify a release mechanism here and then add in the source form all the nuclides that will

use the selected release mechanism. Then a different release mechanism can be selected in 

this form before continuing to add the nuclides that will use the newly selected release 

mechanism.
25

4.3 Site Layout

Figure 10. Site Layout Form

The site layout form (Figure 10) allows numerical input of site dimensions. The map interface 

(Section 4.4) can be used to input the same information in an interactive graphical fashion. The 

site layout form is appropriate when measured or computed lengths are available, and it is likely 

to be a quicker way to specify the dimensions of the site. The interactive map interface is 

appropriate when visible features in the map are to be used to define the various areas.

Uncertainty and sensitivity analysis can be performed on any parameter on this form.

The inputs on this form are used by the atmospheric transport module, the direct external 

exposure from the primary contamination module, and to compute the areas of primary 

contamination and the offsite locations of secondary contamination. The atmospheric transport 

model assumes that the primary contamination and the offsite locations of secondary 

contamination are rectangular in shape and that a pair of sides of each of the rectangles is 

oriented in the same direction. The two sides of the primary contamination that meet at the 

lower left corner are the axes of the 
26

coordinate system. Each offsite 

area is defined by the four 

coordinates as shown in figure 11. 

These can be thought of as the 

coordinates of the sides of the 

offsite area.

Bearing of X-axis: This is the 

clockwise angle from north to the 

direction of the positive X-axis.

X Dimension of the Primary 

Contamination: This is the length 

of the side of the idealized primary 

contamination that is parallel to the 

X-axis, the length of the lower side.

Y Dimension of the Primary Contamination: This is the length of the side of the idealized 

primary contamination that is parallel to the Y-axis, the length of the left side.

The X Coordinates of an Offsite Area: These are the X coordinates of the two sides that are 

parallel to the Y-axis. When the save command or one of the form linking arrow commands is 

issued, the code will compare the two X coordinates of each area and interchange them if the 

larger value is entered in the column for the smaller value, and vice versa. 

The Y Coordinates of an Offsite Area: These are the Y coordinates of the two sides that are 

parallel to the X-axis. When the save command or one of the form linking arrow commands is 

issued, the code will compare the two Y coordinates of each area and interchange them if the 

larger value is entered in the column for the smaller value and vice versa. 

All the information that has been entered and saved in the site layout form will be reflected in 

the display map. Conversely, the position and size that have been set and accepted in the map 

interface will be reflected in the site layout form. 

Figure 11. The coordinate system used in 

RESRAD-OFFSITE.

Y axis

X axis

X dimension of 

primary contamination

Larger Y coordinate of offsite area

(0,0)

Y dimension of 

primary contamination

Smaller Y coordinate of offsite area

Smaller X coordinate of offsite area

Larger X coordinate of offsite area
27

4.4 Map Interface

Figure 12. Map Interface

The map interface (Figure 12) can be used to position and, where appropriate, size the objects 

and directions of interest in RESRAD-OFFSITE (primary contamination, offsite dwelling, well, 

surface water body, agricultural fields, direction of groundwater flow, and direction of north), 

either by dragging and dropping or by resizing the corresponding icons. Alternatively, the map 

interface can be used to view the layout that was specified in the standard input forms (site 

layout form, Section 4.3, and groundwater transport form, Section 4.21). It can also be used to 

access the forms specifying the properties of the locations represented by each icon, by rightclicking the icon opens the corresponding form. The forms that are linked to the icons are in the 

Table 1.
28

Table 1. Icon Identification

Icon Form, Section in User’s Guide

N Site layout, Section 4.3

Radioactivity Primary Contamination, Section 4.13

Cow Livestock Feed Growing Areas, 

Section 4.14

Leaf or fruits Agricultural Areas, Section 4.14

House Offsite Dwelling Area, Section 4.15

Well Saturated Zone Hydrology, Section 

4.18

Blue 

circle/ellipse

Surface Water Body, Section 4.20

GW Groundwater Transport, Section 4.21

The process for using the map interface is as follows:

1. View map interface form.

2. Add a background image (using Get Image button).

3. Set the scale (using the Set Scale button) on the basis of a known distance in 

the background map.

4. Move and size the radioactivity icon to define the location of the primary 

contamination.

5. Move and size the other icons to define the corresponding locations. The GW 

(groundwater flow direction) and N (North) icons indicate direction; they 
29

cannot be resized, because size has no meaning for the direction. The well 

cannot be resized because the diameter of the well is not an input.

6. Trace the groundwater flow line passing through the center of the primary 

contamination, if that information is available. 

7. Click on the Accept Changes button.

8. The image location, scale, and object locations will be written to the input file 

when the RESRAD-OFFSITE file is saved. This information is used to display 

the map image and the icons when the input file is opened at a later time.

Details on Using Map Interface

Steps 2 through 8 are described in greater detail below.

Step 2 (in detail): To get an image, click on the Get Image button and navigate to an image 

(bitmap, metafile, enhanced metafile, JPEG, or GIF file) of the site that is large enough to 

contain all the objects of interest and open it.

• Click on the Get Image button on the map interface. A file dialog box will pop 

up (Figure 13).

• Use the file dialog box to navigate to the directory containing the image, 

typically the same folder that contains the RESRAD-OFFISTE input files (for 

example, the highlighted folder, “Userfiles,” in the figure 13).

• Double-click the file to be opened (for example, the highlighted file, 

“HypotheticalSuburbanResidentGroundwaterFlog.jpg,” in the figure 13).
30

Figure 13. Map Interface Dialog Form
31

Step 3 (in detail): Find the scale on the map or find two points on the map that are a known 

distance apart (these points should be as far apart as possible). Move each of the two blue 

arrows to a different point; if using the scale, move each blue arrow to a point on either end of 

the scale. Enter the distance (in meters) between the arrows in the entry box above the Set 

Scale button, then click the Set Scale button. In the example illustrated in Figure 14, it is better 

to set the scale using the Y-axis and the right edge of the surface water body (a distance of 

1250 m) than to use the two points denoting the scale distance of 106 m on the map. This 

reduces the error that results from not placing the blue arrows exactly where you intended. 

Figure 14. Setting the Scale in the Map Interface
32

Step 4 (in detail): Left-click on the source icon (the yellow and black radiation symbol) and drag 

it to the location of the primary contamination. Move the sides of the icon to expand or shrink it 

to cover the entire primary contamination. Notice that all the other icons that represent exposure 

locations and directions move with the source icon (Figure 15). This is why it is necessary to 

locate the primary contamination before locating any of the other icons.

Figure 15. Locating and Sizing the Primary Contamination on the Map Interface
33

Step 5 (in detail): Left-click on each of the other objects in turn and drag them to the appropriate 

locations (Figure 16). Expand or shrink each icon (by moving its sides) to cover the entire area it

represents. The GW icon, which indicates the direction of the groundwater flow from the source; 

the N icon, which indicates north; and the Well icon cannot be resized. If an icon does not 

appear on the map interface, it can be moved onto the map by specifying its location in the site 

layout form (Section 4.3).

Figure 16. Locating and Sizing the Offsite icons on the Map Interface
34

Step 6 (in detail): Click on the Trace Groundwater Flow Line command button if the path of the 

groundwater flow line through the center of the primary contamination is available. The icons 

representing the various locations will be removed, providing a clutter-free map on which to 

trace the flow line (Figure 17). A curved groundwater flow line must be approximated by up to 

10 linear segments. Use the following procedure to trace the curved path on the map interface.

• Grab the large GW icon and move it to the first approximately linear portion of 

the flow line; the small GW icon is anchored to the center of the primary 

contamination and cannot be moved.

Figure 17. Tracing a Groundwater flow line on the Map interface, first segment

• Click on the Extend Flow Line command button to fix the position of the GW 

icon that you just moved and use it to define the next linear approximation of 

the flow line; grab and move the new large GW icon to define the second 

approximately linear portion of the flow line. Continue in this fashion to define 

the flow line with up to 10 linear segments (Figure 18). 
35

Figure 18. Tracing a Groundwater flow line on the Map interface, last segment

• Click on the Compute and Display Flow Distances command button if you 

wish to see the lengths and location of the transport distances. If not, skip to 

the next step. 

The transport distances to the well and the surface water body will be 

displayed on top of the corresponding icons (Figure 19). 
36

• Click on the Well option and then on the “up down” arrow control to see the 

bottom of the perpendicular from the well to the flow line. If it is possible to 

draw perpendiculars from the well to more than one of the line segments, the 

up down arrow control can be used to scroll over all of these possibilities and 

to view the corresponding distances.

• The same procedure can be repeated after clicking on the Surface water 

body option to see the bottom of the perpendicular from the center of the 

surface water body to the flow line.

Figure 19. Groundwater transport distances computed by Map Interface
37

• Click on the Keep Changes to Flow Line button (Figure 19) to preserve the 

flow line that was defined in the preceding steps and to return to the view of 

the map that displays all the icons. 

Figure 20. Fully Defined Map Interface

Step 7 (details): Be sure to click on either of the Accept Changes buttons (Figure 20) if you want 

to save all the locations and directions that you defined in the map interface.
38

• The location and transport distances specified in the map interface will be 

transferred to the appropriate forms when changes are accepted. These 

forms include the site layout form (Section 4.3), the primary contamination 

form (Section 4.13), the groundwater transport form (Section 4.21), and the 

external radiation shape and area factors form (Section 4.26). The numbers 

that were transferred to the site layout form for this example are shown in 

figure 21 to illustrate their deviations from the dimensions used to draw the 

figure. These deviations occur because of the difficultly of placing the location 

and scale icons exactly in the correct positions.

Figure 21. Site Layout Form

• Any changes made in the map interface since they were last accepted will be 

lost if you click on either of the two Cancel Changes buttons (Figure 20).
39

Step 8 (details): The image location, scale, and object locations will be written to the 

input file when the RESRAD-OFFSITE file is saved. This information is used to display 

the map image and the icons when the input file is opened at a later time. If the input file 

is being sent to a different computer, the image files should also be sent in order for it to 

be displayed on that computer. The Get Image command may need to be used on the 

receiving computer after opening the input file if the structures and/or the names of the 

RESRAD-OFFSITE directories are different on the two computers. If the image file is not 

sent, the image of the map cannot be displayed; however, the icons will be in their 

specified locations, so the analysis will yield the same results.
40

4.5 Source (Initial Concentrations of Radionuclides at Site)

Figure 22. Source Form

The Source form (Figure 22) does not have a cancel feature. Any changes made to this form 

can be reversed only by re-inputting the original inputs.

An uncertainty analysis can be performed on the concentration of any nuclide that has a 

nonzero initial concentration. This can be done by clicking on the nuclide in the left scroll box 

(List of Nuclides Present at the Site) and then pressing the F8 key. Only positive values can be 

sampled for the concentration. A discrete distribution that produces a zero value should not be 

used because it will cause the code to crash. One parameter at a time sensitivity analysis 

cannot be performed on the concentration because the response is known to be directly 

proportional to concentration under all release models of RESRAD-OFFSITE.

List of Nuclides in Database: This list (in the right scroll box) shows all the radionuclides in the 

database that have a half-life greater than the cutoff half-life selected in the Title form. Any 

nuclides that are lacking one or more of the dose or slope factors are flagged with a “No DCFs” 

comment on the side. This notifies the user that these nuclides cannot be analyzed unless a 

library with a nonzero dose and slope factors is selected.
41

List of Nuclides Present at the Site: This list (in the left scroll box) shows radionuclides that 

will be explicitly considered in the current analysis. It includes all radionuclides that were 

specified to be initially present at the site and their principal nuclide progeny (see cutoff half-life

in the Title form). Although the fate and transport of any associated radionuclides will not be 

modeled explicitly, their contributions to dose and risk will be included on the basis of the 

assumption that they are in secular equilibrium with their principal radionuclide parent.

Add Nuclide: To add a radionuclide, either click on its name in the right scroll box and then 

click the Add Nuclide button, or just double-click on its name in the right scroll box. The 

radionuclide will be added to the left scroll box with a concentration specified in the top center 

input box. All potential decay products will be added to the left scroll box with a default 

concentration of zero if they are not already present. 

Delete Nuclide: To delete a radionuclide, click on its name in the left scroll box and then click 

on the Delete Nuclide button. All potential decay products that arise only from the deleted 

radionuclide and have an initial concentration of zero will also be deleted automatically.

Nuclide Concentration: This is the radionuclide concentration averaged over an appropriate 

depth and area. See Section 3.3 of the RESRAD (onsite) Manual and the RESRAD Data 

Collection Handbook for more details.

• To change the concentration of a radionuclide that is in the left scroll box:

Click on the radionuclide in the left scroll box and type in the concentration.

• To change the default concentration when adding new radionuclides: Click on 

the right scroll box, then enter the concentration in the top center box. To add 

radionuclides with this concentration, see above description.

Accessing Other Related Forms

The three command buttons on this form, which are listed below, provide access to the three 

forms that contain the radionuclide-dependent inputs. Alternatively, the first form can be opened 

by clicking on the forward arrow button on this form, and then the other two forms can be 

accessed by continuing to use the forward arrow buttons on the successive forms. If the 

computer monitor is large enough (17 inches or more diagonally), all of these forms can be 

viewed simultaneously by clicking on the All Nuclide Factors button. All three forms can also be 

accessed by double-clicking on the radionuclide name in the left scroll box.

Source Release and Deposition Velocity: Use this button to specify the release mechanism, 

the parameters of the release mechanism, and the temporal variation of nuclides eligible for 

release, as well as to specify the deposition velocity of the material with which the nuclide is 

being transported in the atmosphere. This opens the Source Release and Deposition Velocity 
42

form (Section 4.6). As discussed in Appendix A, it is also possible to override the source term 

module of RESRAD-OFFSITE.

Distribution Coefficients: Use this button to open the Distribution Coefficients form 

(Section 4.7).

Transfer Factors: Use this button to access the Transfer Factors form (Section 4.8).
43

4.6 Source Release and Deposition Velocity

Figure 23. Source Release and Deposition Velocity Form

RESRAD-OFFSITE offers a choice of three release mechanisms: Version 2 release 

methodology, first-order rate-controlled release with transport, and instantaneous equilibrium 

desorption release. The temporal variation of the eligibility of nuclides for release can be 

specified for the latter two release mechanisms. Uncertainty and sensitivity analysis can be 

performed on any parameter on the Source Release and Deposition Velocity form (Figure 23). 

Version 2 Release Methodology: This was the only release mechanism available in RESRADOFFSITE through Version 2.6; it is based on the release mechanism of RESRAD (onsite) code. 

If a nonzero first-order leach rate is specified, it will be used to compute the contaminant 

concentration in the region of primary contamination and the releases to groundwater. Because 
44

the contaminant concentration in the primary contamination contributes to the releases to the 

atmosphere and to surface runoff, the leach rate indirectly affects those two releases as well. If 

a zero is entered, the code will estimate a release rate on the basis of the equilibrium desorption 

concentration using the specified distribution coefficient (Figure 24). 

Figure 24. Specifying Inputs for Version 2 Release Methodology

First-Order Rate-Controlled Release with Transport: The radionuclides that are released 

from material at the top of the primary contamination need to travel the entire depth or thickness 

of the primary contamination before they become part of the release from the primary 

contamination. Those radionuclides that are released from material at the bottom of the primary 

contamination immediately become part of the release from the primary contamination. This 

mechanism, which can be selected as shown in Figure 25, extends the Version 2 methodology 

by considering the travel time of the radionuclides within the primary contamination.
45

Figure 25. Specifying Inputs for a First Order Rate Controlled Release with Transport

First-Order Rate-Controlled Release with Transport, with Radionuclide-Bearing Material 

Becoming Available for Release Linearly over Time: It is possible to specify a release where 

the radionuclide-bearing material becomes susceptible to release linearly over time. In the 

example in Figure 26, the radionuclide-bearing material is intact and does not release nuclides 

for a period of 200 years. At that time, the radionuclides in 25% of the material become 

available for release. Over the next 100 years, the nuclides in an additional 65% of the material 

become available for release, with the percentage of release susceptible material increasing 

linearly over time from 25% to 90%. The leach rate increases linearly over time from the initial 

leach rate (0.001/year in this example) to the final leach rate (0.002/year in this example).
46

Figure 26. Specifying Inputs for a First Order Rate Controlled Release where the 

Radionuclide-Bearing Material Becomes Susceptible to Release Linearly 

over Time

First-Order Rate-Controlled Release with Transport with Radionuclide-Bearing Material 

Becoming Available for Release Stepwise over Time: It is possible to specify a release 

where the radionuclide bearing material becomes susceptible to release stepwise over time. In 

the example in Figure 27, the radionuclide-bearing material is intact and does not release 

nuclides for a period of 200 years. At that time, the radionuclides in 25% of the material become 

available for release, and the nuclides in this fraction of the material are released at the initial 

leach rate. After another 100 years, at year 300, the nuclides in an additional 65% of the 

material become available for release. The nuclides in this fraction of material are released at 

the final leach rate. The leach rates from the two fractions of material do not vary over time. 
47

Figure 27. Specifying Inputs for a First Order Rate Controlled Release where the 

Radionuclide-Bearing Material Becomes Susceptible to Release Stepwise over 

time

Instantaneous Equilibrium Desorption Release: In this release mechanism, the radionuclides 

are modeled as being released instantaneously from the radionuclide-bearing material (Figure 

28). The radionuclides are then transported through the primary contamination according to the 

specified distribution coefficient. If the primary contamination is conceptualized as a mixture of 

soil and an ion-exchange medium on which the radionuclides are adsorbed, then weighted 
48

average values need to be input for the distribution coefficients and the physical characteristics 

of the primary contamination.

Figure 28. Specifying Inputs for an Instantaneous Equilibrium Desorption Release

Instantaneous Equilibrium Desorption Release with Radionuclide-Bearing Material 

Becoming Available for Release Linearly over Time: It is possible to specify a release where 

the radionuclide-bearing material becomes susceptible to release linearly over time. In the 

example in Figure 29, the radionuclide-bearing material is intact and does not release nuclides 

for a period of 200 years. At that time, the radionuclides in 25% of the material become 

available for release. Over the next 100 years, the nuclides in an additional 65% of the material 

become available for release, with the percentage of release susceptible material increasing 

linearly over time from 25% to 90%. The radionuclides are released by partitioning between the 

solids in the soil and the soil moisture according to the specified distribution coefficient.
49

Figure 29. Specifying Inputs for an Instantaneous Release where the RadionuclideBearing Material Becomes Susceptible to Release Linearly over Time

Instantaneous Equilibrium Desorption with Radionuclide-Bearing Material Becoming 

Available for Release Stepwise over Time: It is possible to specify a release where the 

radionuclide-bearing material becomes susceptible to release stepwise over time. In the 

example in Figure 30, the radionuclide-bearing material is intact and does not release nuclides 

for a period of 200 years. At that time, the radionuclides in 25% of the material become 

available for release. After another 100 years, at year 300, the nuclides in an additional 65% of 

the material become available for release. The radionuclides in both fractions of material are 

released by partitioning between the solids in the soil and the soil moisture according to the 

specified distribution coefficient.
50

Figure 30. Specifying Inputs for an Instantaneous Release where the RadionuclideBearing Material Becomes Susceptible to Release Stepwise over Time

Release to Atmosphere: The RESRAD-OFFSITE code computes the release of particulates to 

the atmosphere (and to runoff) using the radionuclide concentration in the surface layer. By 

default, only the nuclides in the material in the release-susceptible form are released from the 

surface layer. The user can choose to include both the release-susceptible form and the 

release-immune form in the atmospheric release calculations. The radionuclides that are 

released into the soil moisture in the primary contamination can resorb onto the solids in soil; 

these radionuclides are not included in the calculations of the releases from the surface soil,

even though some of those radionuclides may still be within the mixing layer.
51

Deposition Velocity: The deposition velocity of the material with which the nuclide is being 

transported is used by the code to account for loss from dry deposition along the atmospheric 

transport path and to compute the deposition flux at the offsite locations.

Click on the up or down arrow next to the radionuclide name to save the inputs for the currently 

displayed radionuclide and to view the inputs for the next or previous radionuclide.
52

4.7 Distribution Coefficients

Figure 31. Distribution Coefficients Form for Version 2 Release

Distribution coefficients are the ratios of the mass of solute that is adsorbed on or precipitated 

onto the soil (per unit of dry mass) to the solute concentration in the liquid phase at the different 

transport zones and locations of accumulation. Default values are provided for each 

radionuclide; however, site-specific values should be used since literature values can vary over 

many orders of magnitude, depending on the chemical form, soil type, pH, redox potential, and 

the presence of other ions. The Distribution coefficients in the different transport zones and 

regions of accumulation are input in the form shown in Figure 31. Uncertainty and sensitivity 

analysis can be performed on the distribution coefficients.

Click on the up or down arrow next to the radionuclide name to save the distribution coefficients 

of the current radionuclide and to view the distribution coefficients of the next or previous 

radionuclide.

Contaminated Zone: If a Version 2 release methodology is specified, this distribution 

coefficient is used to estimate a first-order release rate when the user does not specify a release 

rate. In this case, the form has a pink horizontal line to differentiate the distribution coefficient 

that is used to estimate the leach rate from the distribution coefficients that are used to model 

transport.
53

This distribution coefficient is used to compute the radionuclide transport rate within the primary 

contamination for the other release methodologies. In these cases, the distribution coefficient in 

the contaminated zone is used for the same purpose as the distribution coefficients in the 

unsaturated and saturated zones. There is then no need to separate the distribution coefficients 

of those zones in this case, and the pink horizontal line is not displayed as shown in Figure 32. 

Figure 32. Distribution Coefficients Form for Version 3 Releases

Unsaturated Zone and Saturated Zone: These distribution coefficients are used to compute 

the radionuclide transport rate for groundwater transport calculations.

Sediment in Surface Water Body: This distribution coefficient is used to compute the 

concentration of the radionuclide in the surface water body.

Fruit, Grain, Nonleafy Fields; Leafy Vegetable Fields; Pasture, Silage Growing Areas; 

Livestock Feed Grain Fields; Dwelling Site: These five distribution coefficients for agricultural 

fields, pastures, and dwelling sites are used to account for leaching when accumulation in the 

fields, pastures, and dwelling sites is being computed.

Clicking on the button displaying the number of unsaturated zones causes the Preliminary 

Inputs form (Section 4.2) to open, because the number of unsaturated zones can be changed 

only on the Preliminary Inputs form.
54

4.8 Transfer Factors

Figure 33. Transfer Factors Form

Uncertainty and sensitivity analysis can be performed on the transfer factors. The transfer 

factors form (Figure 33) is linked to the list of radionuclides specified to be present at the site.

Therefore, it displays the transfer factors for each radionuclide that is specified to be present at 

the site. However, the transfer factors are element specific; thus, any changes made to the 

factors of an isotope will be used for all the isotopes of that element. The form displays the 

radionuclide name and the element name to remind the user that the transfer factors are 

element specific. The factors for each element and radionuclide that were specified for the site 

can be viewed by clicking on the up or down button next to the radionuclide name.

Soil to Plant Transfer Factor: This is the root uptake transfer factor, which is the ratio between 

the contaminant concentration in the edible plant and that in the soil upon which the plant is 

grown. The RESRAD database contains only one default value for each element. Values 

appropriate for the site-specific vegetation must be entered in the four input boxes. Values 

displayed for tritium (H-3) (Figure 34) and for carbon-14 (C-14) cannot be changed by the user 

because the transfer factors are computed by the code (see Appendix L of the RESRAD 

Manual).
55

Figure 34. Transfer Factors Form for H-3 and C-14

Intake to Animal Product Transfer Factor: This is the ratio between the concentration of the 

radionuclide in meat or milk and the rate of intake of the radionuclide by livestock. Values 

displayed for H-3 and for C-14 cannot be changed by the user because the transfer factors are 

computed by the code (see Appendix L of the RESRAD Manual).

Water to Aquatic Food Transfer Factor: This is the ratio between the radionuclide 

concentration in the edible parts of aquatic food and that in the water in which the aquatic food 

sources live.
56

4.9 Set Pathways

Figure 35. Set Pathways DOS-Emulator

All pathways, except the radon pathway, are active by default but can be turned off. The user 

can activate the radon pathway after selecting a radon precursor.

An inactive pathway can be activated by clicking on either the crossed-out icon corresponding to 

the pathway or the name of the pathway, or by using the hotkey (Alt + underlined letter) 

corresponding to that pathway (Figure 35).

An active pathway can be deactivated by clicking on either the icon corresponding to the 

pathway or the name of the pathway, or by using the hotkey (Alt + underlined letter) 

corresponding to that pathway.

 

 
57

4.10 Reporting Times

Figure 36. Reporting Times Form

None of the inputs on the Reporting Times form (Figure 36) are eligible for uncertainty analysis 

or for sensitivity analysis.

Times at which Output is Reported: These are the times after the radiological survey when 

results are to be reported in the textual output. A time horizon of 1,000 years is commonly used; 

however, calculations can be carried out to longer periods to identify potential problems from 

delayed contributions from the groundwater or other pathways. The forecast time horizon is the 

sum of the last reporting time and the exposure duration. Results are always calculated and 

reported for year 0.

The code predictions are available at each of the intermediate time points generated by the 

specification in the Title form (Section 4.1). Interpolation is performed between those time points 

to produce the textual report at the times specified in this form.

Add: Use this button to add a time:

• Click on the Add button and a new clock icon and time box will appear. Set 

the time following the change time procedure, or

• Click the right mouse button while the cursor is in the frame containing the 

clock icons.
58

Remove: Use this button to remove a time:

• Click on the appropriate time box or clock icon, then click on the Remove 

button.

To change a time:

• Click on the appropriate time box and enter new value, or

• Click on the appropriate clock icon and drag to desired time location.

Storage Times: The Storage Times form can be assessed by clicking on this button. The 

Storage Times form is the next linked form, so the forward arrow can also be used to get to it.
59

4.11 Storage Times

Figure 37. Storage Time Form

Uncertainty and sensitivity analysis can be performed on the storage times.

Storage Times: These are the various amounts of time over which foodstuffs and water are 

stored before being consumed or used (Figure 37). The concentrations of radionuclides in food 

and water are adjusted for decay and ingrowth during this period. See Appendix D of the 

RESRAD Manual for more details.
60

4.12 Physical and Hydrological Parameters

Figure 38. Physical and Hydrological Properties Form

Uncertainty and sensitivity analysis can be performed on the parameters listed on the Physical 

and Hydrological Parameters form (Figure 38).

Precipitation: This the annual average value of precipitation at the site. It is used to compute 

the infiltration rate in the primary contamination, the leach rates in all areas, and the 

evapotranspiration of tritium. The leach rate is used to compute contaminant concentration in 

soil in the agricultural, pasture, and dwelling areas and in some cases at the primary 

contamination site. The infiltration rate affects the rate of transport through the unsaturated zone

and in the primary contamination. 

Wind Speed: This is the annual average wind speed used to calculate the area factor for 

inhalation and foliar deposition (see Appendices B and D of the RESRAD Manual). It is also 

used for ingrowth calculations for the radon pathway (Appendix C) and in the tritium and 

C-14 models (Appendix L). It is computed by the code using the wind speed and frequencies 

specified in the Atmospheric Transport form.
61

Accessing Other Related Forms

The four command buttons on this form (Figure 38), Contaminated Zone and Cover, Agricultural 

Areas, Livestock Feed Growing Areas, and Offsite Dwelling Site, provide access to the four 

forms that provide physical and hydrological data on four subarea properties (see Sections 4.13, 

4.14, and 4.15). Clicking on any of these four buttons opens the respective form. The current 

parent form will not be closed and will remain in the background, and it will appear again when 

the other form is exited. Alternatively, the first form can be opened by clicking on the forward 

arrow button on this form; the other three forms can be accessed by continuing to use the 

forward arrow buttons on the successive forms.
62

4.13 Primary Contamination (Contaminated Zone and Cover): Physical and 

 Hydrological Data

Figure 39. Primary Contamination Form

Uncertainty and sensitivity analysis can be performed on any parameter that is an input on the 

Primary Contamination form (Figure 39). Parameters that are not inputs to the code are shown 

in gray italics for information only.
63

Area of Primary Contamination: This is not a direct input; it is computed using the information 

input in the Site Layout form. The primary contamination is a compact area that contains the 

locations of all soil samples with radionuclide concentrations that are clearly (i.e., two standard 

deviations) above background.

Length of Contamination Parallel to Aquifer Flow: This is the distance between two parallel 

lines that are perpendicular to the direction of the aquifer flow: one at the up-gradient edge of 

the contaminated zone, and the other at the down-gradient edge. It is used in groundwater 

transport calculations. The code computes this value from the information input in the map 

interface. The user can change the value computed by the code. The connection between this 

form and the map interface is one-directional; the information entered in this form will not affect 

the map interface.

Depth of Soil Mixing Layer: This is the thickness of the surface soil at the location of the 

primary contamination, which may be assumed to be mixed uniformly from time to time as a 

result of anthropogenic or physical processes. It is used to calculate the concentration of 

contaminants in surface soil.

Deposition Velocity of Dust: This is the representative deposition velocity of dust at the 

location of primary contamination. It is used to compute the release to the atmosphere on the 

basis of the assumption that there is no net deposition of particulates at the site.

The next three inputs and the precipitation rate are used to compute the infiltration rate and to 

compute the evapotranspiration of tritium from the primary contamination. They affect all 

releases from the primary contamination as well as the transport rate through the unsaturated 

layers.

Irrigation Applied per Year: This is the volume of irrigation water that is applied over a period 

of 1 year per unit area of land. It is not the actual rate of irrigation during the growing season; 

instead, it is the irrigation rate averaged over 1 year.

Evapotranspiration Coefficient: This is the fraction of precipitation and irrigation water that 

penetrates the topsoil, which is lost to the atmosphere by evaporation and by transpiration by 

vegetation.

Runoff Coefficient: This is the fraction of precipitation that does not penetrate the topsoil, and 

instead leaves the area of concern as surface runoff; no loss is assumed for irrigation water.

The next six inputs are used to compute the rate of erosion. Erosion Rate is not an input in 

RESRAD-OFFSITE; it is displayed for the information of users.
64

Rainfall and Runoff Index: This is a measure of the energy of the rainfall. It is used to compute 

the erosion rate.

Slope-Length-Steepness Factor: This factor accounts for the effect the profile of the terrain 

has on the erosion rate.

Cover and Management Factor: This factor (formerly called the Cropping-Management 

Factor) accounts for the effects land use, vegetation, and management have on the erosion 

rate.

Support Practice Factor: This factor (formerly called the Conservation Practice Factor) 

accounts for the effects conservation practices have on the erosion rate.

Dry Bulk Density (of Soil in the Contaminated Zone and in Clean Cover): This is the mass 

of (dry) solids in a unit volume of soil in the respective layers of soil. In addition to being used to 

compute the erosion rate, this is also used to compute the exposure to external radiation. The 

density in the contaminated zone is also used to compute the release to groundwater, and thus 

the concentration in the primary contamination. 

Soil Erodibility Factor: This is a measure of the susceptibility of the soil to erosion.

Thickness (of Contaminated Zone): This is the distance (in meters [m]), between the 

uppermost and lowermost soil samples with radionuclide concentrations that are clearly (i.e., 

two standard deviations) above background.

Thickness (of Clean Cover): This is the distance from the ground surface to the location of the 

uppermost soil sample with radionuclide concentrations that are clearly above background.

Total Porosity (of Contaminated Zone and Clean Cover): This is the fraction of soil (by 

volume) that is occupied by liquid and gaseous phases in the respective layers.

Field Capacity (of Contaminated Zone): This is the volumetric moisture content of soil at 

which (free) gravity drainage ceases. This is the amount of moisture that will be retained in a 

column of soil against the force of gravity.

b Parameter (of Contaminated Zone): The soil-specific exponential b parameter relates the 

hydraulic conductivity of partially saturated soil to its moisture content.
65

Hydraulic Conductivity (of Contaminated Zone): This is the apparent flow velocity through 

the contaminated zone under a unit hydraulic gradient.

Effective Porosity: This is the fraction of soil (by volume) through which water flows. Part of the 

soil moisture may not contribute to the movement of contaminants. Therefore, the effective 

porosity will be less than or equal to the total porosity.

Longitudinal Dispersivity: This is the ratio between the longitudinal dispersion coefficient and 

pore water velocity. It has the dimension of length. This parameter depends on the thickness of 

the zone and ranges from one one-hundredth of the thickness to the order of the thickness.

Volumetric Water Content (of Clean Cover): This is the fraction of soil (by volume) that is 

occupied by water. 
66

4.14 Agricultural Areas and Livestock Feed Growing Areas: Physical and 

 Hydrological Data

Figure 40. Agricultural Area Form

Uncertainty and sensitivity analysis can be performed on any parameter that is an input on the 

Agricultural Areas and Livestock Feed Growing Areas forms (Figures 40 and 41).

Area: This is the area of agricultural land on which the crop is cultivated, or pasture land on 

which the livestock are allowed to feed. This is not a direct input, but is computed based on the 

information input in the site layout form.

Fraction of Area Directly over the Primary Contamination: This is the areal fraction of the 

agricultural or pasture land that lies directly above the primary contamination. If the entire area 

is completely on the contamination, the fraction is one; if the entire area is away from the region 

of primary contamination, the fraction is zero. This fraction is used to account for direct root 

uptake of contaminants from the primary contamination.
67

Figure 41. Livestock Feed Growing Areas Form

Irrigation Applied per Year: This is the volume of irrigation water that is applied over a period 

of 1 year per unit area of land. It is not the actual rate of irrigation during the growing season; it 

is the irrigation rate averaged over 1 year.

Evapotranspiration Coefficient: This is the fraction of precipitation and irrigation water that 

penetrates the topsoil and is lost to the atmosphere due to evaporation and to transpiration by 

vegetation.

Runoff Coefficient: This is the fraction of precipitation that does not penetrate the topsoil but 

leaves the area of concern as surface runoff; no loss is assumed for irrigation water.

Depth of Soil Mixing Layer or Plow Layer: This is the thickness of the surface soil, which may 

be assumed to be mixed uniformly from time to time as a result of anthropogenic or physical 

processes. It is used to calculate offsite accumulation.

Volumetric Water Content of Soil: This is the fraction of soil moisture by volume.
68

Dry Bulk Density of Soil: This is the mass of solids in a unit volume of soil.

Soil Erodibility Factor: This is a measure of the susceptibility of the soil to erosion.

Slope-Length-Steepness Factor: This factor accounts for the effect the profile of the terrain 

has on the erosion rate.

Cover and Management Factor: This factor (formerly called the Cropping-Management 

Factor) accounts for the effects land use, vegetation, and management have on the erosion 

rate.

Support Practice Factor: This factor (formerly called the Conservation Practice Factor) 

accounts for the effects conservation practices have on the erosion rate.

Total Porosity: This is the fraction of soil (by volume) that is occupied by liquid and gaseous 

phases.
69

4.15 Offsite Dwelling Area: Physical and Hydrological Data

Figure 42. Offsite Dwelling Area Form

Uncertainty and sensitivity analysis can be performed on any parameter that is an input on the 

Offsite Dwelling Area form (Figure 42). The descriptions for most of these parameters are the 

same as the descriptions for the agricultural and pasture lands in Section 4.14.

Area: This is the area of the plot of land on which the offsite dwelling is located. This is not a 

direct input, but is computed based on the information input in the site layout form.

Irrigation Applied per Year: This is the volume of irrigation water that is applied to the lawn or 

home garden over a period of 1 year per unit area of land.
70

4.16 Atmospheric Transport Parameters

Figure 43. Atmospheric Transport Form

Uncertainty analysis can be performed on all but the following parameters on the Atmospheric 

Transport Parameters form: Grid spacing for areal integration, the joint frequency, and the two 

parameters involving choices. One-parameter-at-a-time sensitivity analysis can be performed 

on all but the two parameters involving choices. The code will not check whether the sum of the 

frequencies of the joint frequency distribution sums equal to one when one-parameter-at-a-time 

sensitivity analysis is performed on a joint frequency. 

Release Height: This is the height of the release above the ground level at that location. 

Release Heat Flux: This is the heat energy that accompanies the contaminant release. It is 

used to account for the rise of the plume.

Anemometer Height: This is the height at which the wind speed was measured.
71

Ambient Temperature: This is the temperature of the air at the location of release.

AM and PM Atmospheric Mixing Heights: The atmospheric mixing height is the thickness of 

the layer of air that is bounded by the ground surface and a layer of stable air above it. The 

spreading of the contaminants is limited to the thickness of the mixing layer. AM and PM refer to 

the portion of the day during which the measurement was taken.

Dispersion Model Coefficients: This is the formulation used to generate the dispersion 

coefficients for the atmospheric transport model.

Wind Speed Terrain: The choice of terrain determines the relationship between the wind speed 

and the elevation above the ground surface.

Elevation of Offsite Location, relative to the Ground Level at Primary Contamination:

When the ground level at the offsite location is above the ground level at the site of primary 

contamination, the code adjusts for the upward deflection of the wind. It is the difference in the 

height of the ground surface at the offsite location of contaminant accumulation and the height 

of the ground surface at the site of primary contamination.

Grid Spacing for Areal Integration: The primary contamination and the offsite receptor areas 

are assumed to be rectangular in shape (as defined in Section 4.3), when modeling the 

atmospheric transport. Rather than use a single transport distance from the center of the source 

to the center of the receptor, the code provides the option to subdivide the source and receptor 

areas into smaller squares or rectangles. The transport from each subdivision of the source to 

each subdivision of the offsite receptor area is computed and summed together to produce a 

better estimate of the atmospheric transport. Smaller grid spacings improve the accuracy of the 

calculations, but they require a longer computation time. This input is the maximum dimension 

of each subdivided rectangle.

Read Meteorological STAR File: This button is used to select the data file that contains the 

joint frequency distribution of the wind speed and stability class in STAR format. Files 

containing the meteorological data at a number of airports are placed in the .\metfiles\

subdirectory during installation.

Modify Joint Frequency Data Read from STAR File: The data read from a STAR file is locked 

to prevent accidental alteration. This box must be checked if the user wants to change the data 

(joint frequencies, wind speed) that were read. This label also shows the name of the 

metrological data STAR file that was read.

Wind Speed: This is the average wind speed for the wind speed interval. 
72

Joint Frequency (of Wind Speed, Wind Direction and Stability Class): This is the joint 

frequency distribution (i.e., it is the fraction of the time during which the atmospheric conditions 

fall within each wind speed interval, wind direction, and stability class combination). There are 

six atmospheric stability classes (A through F), six wind speed intervals, and 16 wind directions.

The form displays the joint frequency for the direction specified in the drop-down box. The 

information for each wind direction can be viewed and edited by selecting the desired direction 

from the drop-down box. Both the direction from which wind blows and the direction toward 

which it blows are shown in order to avoid confusion; customarily, wind is identified by the 

direction from which it blows rather than by the direction toward which it blows.
73

4.17 Unsaturated Zone Hydrology

Figure 44. Unsaturated Zone Hydrology Form

Uncertainty and sensitivity analysis can be performed on any parameter on the Unsaturated 

Zone Hydrology form (Figure 44) except the number of unsaturated zones.

Number of Unsaturated Zones: This is the number of partially saturated layers between the 

primary contamination and the saturated zone. The number of unsaturated zones can be 

changed only in the Preliminary Inputs form (Section 4.2). The code has provisions for up to five 

different horizontal strata. Clicking on the button displaying the number of unsaturated zones 

causes the Preliminary Inputs form to open. Because the distribution coefficients are likely to be 

different for each zone, the Distribution Coefficient form (Section 4.7) is also opened.

Thickness: This is the thickness of the specific unsaturated zone.

Dry Bulk Density: This is the mass of solids in a unit volume of soil in the specific unsaturated 

zone.

Total Porosity: This is the fraction of soil (by volume) that is occupied by liquid and gaseous 

phases.

Effective Porosity: This is the volume fraction of soil through which water flows. Part of the soil 

moisture may not contribute to the movement of contaminants. 
74

Field Capacity: This is the volumetric moisture content of soil at which (free) gravity drainage 

ceases, or the amount of moisture that will be retained in a column of soil against the force of 

gravity. This is the minimum moisture content of the unsaturated layer in the absence of 

evapotranspiration and root uptake.

Hydraulic Conductivity: This is the apparent flow velocity of water through the contaminated 

zone under a unit hydraulic gradient.

b Parameter: The soil-specific exponential b parameter relates the hydraulic conductivity of 

partially saturated soil to its moisture content.

Longitudinal Dispersivity: This is the ratio between the longitudinal dispersion coefficient and 

pore water velocity. It has the dimension of length. This parameter depends on the thickness of 

the zone and ranges from one one-hundredth of the thickness to the order of the thickness.
75

4.18 Saturated Zone Hydrology

Figure 45. Saturated Zone Hydrology Form

Uncertainty and sensitivity analysis can be performed on any parameter whose value can be 

input on the Saturated Zone Hydrology form (Figure 45).

Thickness of Saturated Zone: This is used when dispersion in the vertical direction in the 

saturated zone is being modeled. It is also used to check that the total groundwater flow under 

primary contamination exceeds the inflow from infiltration through the primary contamination.

Dry Bulk Density of Saturated Zone: This is the mass of solids in a unit volume of soil in the 

specific unsaturated zone.

Total Porosity of Saturated Zone: This is the fraction of soil (by volume) that is occupied by 

liquid and gaseous phases.

Effective Porosity of Saturated Zone: This is the fraction of soil (by volume) through which 

water flows. Part of the soil moisture may not contribute to the movement of moisture and 

contaminants. 
76

Hydraulic Conductivity of Saturated Zone: This is the apparent flow velocity of water through 

the contaminated zone under a unit hydraulic gradient.

There are two columns for the remaining properties specified in the form, the first for transport 

from the primary contamination to the well and the second for transport to the surface water

body.

Hydraulic Gradient of Saturated Zone: This is the slope of the surface of the water table.

Depth of Aquifer Contributing: Water flowing through the specified depth of the aquifer is 

assumed to be intercepted by the well or surface water body. This parameter is used to 

calculate the contaminant concentration in well water or the contaminated flux into the surface 

water body. 

Longitudinal Dispersivity of Saturated Zone: This is the ratio between the longitudinal 

dispersion coefficient and pore water velocity. It has the dimension of length. This parameter 

depends on the length of the saturated zone.

Horizontal Lateral Dispersivity of Saturated Zone: This is the ratio between the horizontal 

lateral dispersion coefficient and pore water velocity. It has the dimension of length. 

Vertical Lateral Dispersivity of Saturated Zone: This is the ratio between the vertical lateral 

dispersion coefficient and pore water velocity. It has the dimension of length. 
77

4.19 Water Use

Figure 46. Water Use Form

The quantities of water obtained from the two sources of water are the focus of the Water Use 

form (Figure 46). The water requirements of humans, livestock, and irrigation are in the first 

column. The water requirements also appear in other input forms; if they are changed in one 

form, the other will be updated immediately. The second and third columns are the fractions of 

these water requirements that are obtained from the contaminated surface water body and 

contaminated well. These fractions can add up to less than one if water from uncontaminated 

sources is also used. Uncertainty and sensitivity analysis can be performed on any parameter 

that is an input on this form except the number of individuals as noted below. The user must 

ensure that the sum of the pair of fractions does not exceed unity when performing uncertainty 

analysis.

Water Consumed by Humans: This is the total amount of water consumed by an individual; it 

includes water that is used in the preparation of and consumed with food.

Water Used in Dwelling: This is the total amount of water used in the home. It includes water 

used for cleaning, washing, showering/bathing, and so forth. It is used to compute the dose from 

waterborne radon.
78

Water for Beef Cattle: This is the amount of water consumed by each individual animal raised 

for meat.

Water for Dairy Cows: This is the amount of water consumed by each individual animal raised 

for milk production.

Number of Individuals: These are the number of humans or livestock that obtain the specified 

water needs from the water source. These inputs are used only to compute the required 

minimum well pumping rate and are not used by the computational code. These inputs are not 

eligible for uncertainty analysis.

Irrigation Applied per Year: This is the volume of irrigation water that is applied over a period 

of 1 year per unit area of land. It is not the actual rate of irrigation during the growing season; it 

is the irrigation rate averaged over 1 year.

Well Pumping Rate Needed To Support Specified Water Use: This is the total volume of 

water that needs to be withdrawn from the well to satisfy the demand described in this form. It is 

provided to help the user select an appropriate well pumping rate. This value is computed every 

time a change is made to an input in this form. The well pumping rate is increased 

automatically, so it will never be less than this minimum required rate.

Well Pumping Rate: This is the rate at which water is extracted from the well. The interface will 

not accept a well pumping rate that is insufficient to meet the needs specified in this form. While 

the code performs this check for the deterministic case, the user is responsible for ensuring that 

this condition is not violated when performing sensitivity or probabilistic/uncertainty analysis.
79

4.20 Surface Water Body

Figure 47. Surface Water Body Form

Uncertainty and sensitivity analysis can be performed on any parameter that is an input on the 

Surface Water Body form (Figure 47).

Sediment Delivery Ratio: This is the fraction of the contaminated soil that was eroded from the 

primary contamination that reaches the surface water body. This is used to compute the 

contaminant flux from surface erosion.

Volume of Surface Water Body: This is the volume of water in the surface water body.

Mean Residence Time of Water in Surface Water Body: This is the average amount of time 

water spends in the surface water body. It is obtained by dividing the volume of the surface 

water body by the quantity of contaminated water that flows or is extracted from it each year.

Surface Area of Water in Surface Water Body: This is the area of the surface water body. It is 

not a direct input, but is computed based on the information input in the site layout form. It is 

used to compute the contaminant flux from atmospheric deposition.
80

4.21 Groundwater Transport Parameters

Figure 48. Groundwater Transport Form

Subscreens (Accessing Other Related Forms)

Four forms can be accessed by using the four buttons listed. If the forward arrow buttons are 

being used to access each form in turn, the forms would have been accessed before this 

Groundwater Transport form (Figure 48) and need not be revisited from here.

Unsaturated Zone Properties, Saturated Zone Properties, Water Use Parameters, Surface 

Water Body: These buttons can be used to open the respective forms. The current parent form 
81

will not be closed and will remain in the background. It will reappear when the other forms have 

been exited.

Uncertainty and sensitivity analysis can be performed on the distances that are inputs on this 

form. One-at-a-time sensitivity analysis can also be performed on the number of subzones, but 

not uncertainty analysis. Neither uncertainty analysis nor one-parameter-at-a-time sensitivity 

analysis can be performed on the convergence criteria. The code will compute the five 

groundwater transport distances if the locations of the well and the surface water body relative 

to the primary contamination were specified in the map interface. The user can change the 

values computed by the code. The connection between this form and the map interface is onedirectional; the information entered in this form will not affect the map interface.

Distance in the Direction Parallel to Aquifer Flow from Contamination to Well: This is the 

distance (in meters [m]) along a groundwater flow line from the down-gradient edge of the 

primary contamination to the well. It is used in the computation of transport in the saturated 

zone to the well. A negative value indicates that the well is either up-gradient of or within the 

primary contamination. If this value is negative or if the combination of water and land usage 

and exposure pathways indicates that well water has no influence on dose, the computational 

code will skip the well water concentration computations in order to reduce computational time.

Distance in the Direction Parallel to Aquifer Flow from Contamination to Surface Water

Body: This is the distance (in meters [m]) along a groundwater flow line from the down-gradient 

edge of the primary contamination to the up-gradient edge of the surface water body. It is used 

in the computation of transport in the saturated zone to the surface water body. A negative 

value indicates that the surface water body is up-gradient of the primary contamination. If this 

value is negative or if the combination of water and land usage and exposure pathways 

indicates that water from the surface water body has no influence on dose, the computational 

code will skip the surface water computations in order to reduce computational time.

Distance in the Direction Perpendicular to Aquifer Flow from Contamination to Well: This 

is the distance (in meters [m]) between two groundwater flow lines, one through the center of 

the contamination and the other thorough the well. It is used in the computation of dilution due 

to dispersion in the saturated zone, and it applies to water extracted from a well.

Distance in the Direction Perpendicular to Aquifer Flow from Contamination to Right

Edge of Surface Water Body: This is the distance (in meters [m]) between two groundwater 

flow lines, one through the center of the contamination and the other through the right edge of 

the surface contamination. It is used to compute the contamination flux from the groundwater 

into the surface water body.

Distance in the Direction Perpendicular to the Aquifer Flow from Contamination to Left

Edge of Surface Water Body: This is the distance (in meters [m]) between two groundwater 

flow lines, one through the center of the contamination and the other thorough the left edge of 

the surface contamination. It is used to compute the contamination flux from the groundwater 

into the surface water body.
82

Convergence Criterion: This is the fractional accuracy desired in the Romberg integration 

used to calculate the contaminant flux or concentration in groundwater. A lower value will likely 

require the use of a larger number of points in this numerical integration technique, and will thus 

have a longer computation time. For each Romberg refinement or cycle number, the number of 

integrand function evaluations is 2N

, where N is the cycle number. Therefore, if the convergence 

criterion is set too low, the computation time becomes excessive, and convergence may not be 

achieved. If convergence is not achieved, RESRAD will indicate the failure in the QRFAIL.LOG 

file, and the last estimate of the integral using 32,769 points will be used. If the convergence 

criterion is set at zero, Simpson’s rule with 32 integration intervals will be used.

Modeling Transport of Progeny Produced in Transit

RESRAD-OFFSITE has two groundwater transport algorithms. One models the effects of the 

differences in the water-to-soil interaction of the parent nuclide and the progeny nuclides, and 

the other models the longitudinal dispersion. When one of these processes is clearly dominant, 

the user can choose the appropriate algorithm to model the transport of the progeny produced 

in transit. When both the longitudinal dispersion and the differences in the water-to-soil 

interaction are of comparable importance, the prediction of progeny nuclides produced in transit 

in the transport zones can be improved by breaking up the transport zones into a number of 

subzones; then both processes will be modeled over most of the transport path. Additional run 

time will be needed to do this.

Main Subzones in Primary Contamination: This is the number of subzones into which the 

saturated zone is to be divided in order to improve the predictions of progeny nuclides produced 

in transit. 

Main Subzones in Each Partially Saturated Zone: This is the number of subzones into which 

the partially saturated zone is to be divided in order to improve the predictions of progeny 

nuclides produced in transit. 

Main Subzones in Saturated Zone: This is the number of subzones into which the saturated 

zone is to be divided in order to improve the predictions of progeny nuclides produced in transit. 

Modeling Nuclide -Specific Retardation or Dispersion

The two transport algorithms give rise to three choices for the algorithm to be used in the zones 

where the specific atom undergoes transformations. One of three options can be selected to do 

the following:

• Model the effects of the nuclide-specific distribution coefficients of the parent 

and progeny in the zone of transformation and ignore the effects of 

longitudinal dispersion,
83

• Model the effects of longitudinal dispersion and use the retardation factor of 

the parent nuclide for both the parent and the progeny produced in that zone 

and ignore the retardation factor of the progeny, or

• Model the effects of longitudinal dispersion and use the retardation factor of 

the progeny nuclide for both the parent and the progeny produced in that 

zone and ignore the retardation factor of the parent.

Anticlockwise Angle from X-axis to Direction of Groundwater Flow: This input will appear 

only if the GW icon in the map interface was used to specify the direction of groundwater flow.
84

4.22 Ingestion Rates

Figure 49. Ingestion Rates Form

Uncertainty and sensitivity analysis can be performed on any parameter that is an input on the 

Ingestion Rates form (Figure 49).

Consumption Rates: Consumption rates are national averages that are usually site 

independent. Adjustments for regional differences in diet may sometimes be appropriate.

Fraction from Affected Area: This is the fraction of the consumption rates that is obtained from 

any area that is affected by the primary contamination. The entry for drinking water is the sum of 

the fraction obtained from the contaminated well and from the contaminated surface water body.

Clicking on the entry for drinking water will open the Water Use form (Section 4.19); the 

fractions from each water source can be changed in that form.
85

Accessing Other Related Forms

Three forms can be accessed by using the three buttons listed below. Alternatively, the first 

form can be opened by clicking on the forward arrow button on this form; after that, the other 

forms can be opened by continuing to use the forward arrow buttons on the successive forms.

Livestock Factors, Livestock Feed Factors, and Plant Factors: These buttons can be used 

to open the respective forms. The current parent form will not be closed and will remain in the 

background; it will reappear when the form has been exited.
86

4.23 Livestock Intakes (Factors)

Figure 50. Livestock Intakes Form

Livestock intake (i.e., ingestion) rates (Figure 50) are national averages that are usually site 

independent. Adjustments for regional differences in animal husbandry practices are necessary.

The first column is the intake rates for each head of livestock raised for meat, while the second 

column is for each head of livestock raised for milk production. The incidental ingestion of soil 

associated with the ingestion of the two types of feed (grain or pasture/silage) must be specified 

separately because the contaminant concentrations in the soils could be different. Uncertainty 

and sensitivity analysis can be performed on any parameter in this form.
87

4.24 Livestock Feed Factors and Plant Factors

Figure 51. Plant Factors and Livestock Feed Factors Forms

Plant (i.e., vegetable and livestock feed) factors (Figure 51) are related to growth and 

contaminant transfer. They depend on the mix of crops and on regional farming practices.

Uncertainty and sensitivity analysis can be performed on any parameter that is an input on 

these forms.
88

4.25 Inhalation and External Gamma

Figure 52. Inhalation and External Gamma Form

Uncertainty and sensitivity analysis can be performed on any parameter on the Inhalation and 

External Gamma form (Figure 52).

Mass Loading for Inhalation: This is the average mass of respirable particulate in a unit 

volume of air when humans are present at the site (includes the effects of human activity). It is 

used in the inhalation pathway computations.

Mean Onsite Mass Loading: This is the average mass loading of airborne contaminated soil 

particles above the primary contamination. It is used to estimate the contaminant release rate to 

the atmosphere.

Indoor to Outdoor Dust Concentration Ratio: This accounts for the effect of the building 

structure on the level of contaminated dust existing indoors. It is the fraction of outdoor 

contaminated dust that is present indoors. 

External Gamma Penetration Factor: This factor accounts for the effect of the building 

structure on the level of gamma radiation existing indoors. It is the fraction of outdoor gamma 

radiation that penetrates the building.
89

Accessing Other Related Forms

Two forms can be accessed by using the two buttons listed below. Alternatively, the first form 

can be opened by clicking on the forward arrow button on this form, and then the other form can 

be opened by continuing to use the forward arrow button on the first form.

Shape of Primary Contamination, Occupancy Factors: These buttons can be used to open 

the respective forms. The current parent form will not be closed and will remain in the 

background; it will reappear when the form has been exited.
90

4.26 External Radiation Shape and Area Factors

Figure 53. External Radiation Shape and Area Factors Form

The primary contamination is shown in black against a white backdrop in the picture box at the 

top left corner of the form (Figure 53). The primary contamination will change to pink if the 

Calculate Radii and Fractions button near the top of the right side is pressed (Figure 54).

Shape of the Plan of the Primary Contamination: As a default, the shape of the primary 

contamination and the centroid of the offsite dwelling specified in the site layout/map interface 

form are used to calculate the shape and area factors for the external radiation pathway. The 

onsite dwelling is assumed to be located at the center of the primary contamination. This form 

can be used to specify different locations for the dwellings and to define a polygonal shape for 

the primary contamination.

The user may override the radii and fractions. If the user overrides the computed values, the 

code will place a check in the check box as an indication of the override.
91

Changing the Location of the Dwellings

If the primary contamination is not completely within the picture box, change the number in the 

box next to Scale (in the middle near the bottom of the form) until it is visible in its entirety. At 

the top right, select the tab (Onsite tab or Offsite tab) corresponding to each dwelling in turn and 

specify its location, either by inputting the coordinates or by clicking on the location in the picture 

box. If the coordinates of the location are keyed in, the Calculate Radii and Fractions button 

must be pressed to compute the area fractions. This must be done before proceeding to the 

other tab (Onsite tab or Offsite tab). The coordinates of the position of the cursor are shown in 

the Current X and Current Y information boxes at the top center of the form; this information is 

helpful when the cursor is being used to click on the location of the dwelling.

Figure 54. Non-Rectangular Primary Contamination in External Radiation Shape and Area 

Factors Form

Changing the Shape of the Primary Contamination

Set the number in the box next to Scale to the length of the square enclosing the primary 

contamination and the two dwelling locations. Choose the Polygonal option; “Clear” image if 

there is already a polygon in the drawing area. The polygon can be “drawn” using the mouse 

and following the drawing instructions given in the yellow information box on the form.

Alternatively, the vertices of the polygon can be keyed in by following the instructions given in 

the green Instructions box. After the polygon is completed, the location of the onsite and offsite 

dwellings must be specified, as described in the previous paragraph. The area of the polygon 
92

will be computed when the radii and area fractions are computed. The area is displayed in the 

box at the top center of the form (Figure 54).

Because the fraction of each annular area that is contaminated is computed graphically in the 

interface, it is not possible to perform uncertainty or sensitivity analysis on any of the 

parameters on this form. However, it is possible to perform probabilistic analysis on the input on 

the site layout form (Section 4.3). The FORTRAN computational code will compute the 

appropriate radii and fractions for all exposure locations (onsite and offsite dwellings, 

agricultural areas, livestock feed growing area, and pasture) for the probabilistic runs using the 

rectangular shapes specified in the site layout form. 
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4.27 Occupancy Factors

Figure 55. Occupancy Factor Form

The Occupancy factor form (Figure 55) is used to input fractions of time spent in various 

locations.

Fraction of Time Spent on Primary Contamination

• Indoors: This is the fraction of time that the receptor spends in a building situated on 

top of the primary contamination.

• Outdoors: This is the fraction of time that the receptor spends outdoors on 

top of the primary contamination. If any agricultural or pasture land lies over 

the primary contamination, the time spent in that common area should be 

included here and in the entry for that agricultural or pasture land.
94

Fraction of Time Spent in Offsite Dwelling Site

• Indoors: This is the fraction of time that the receptor spends in a building 

situated away from the primary contamination.

• Outdoors: This is the fraction of time that the receptor spends outdoors of 

the offsite dwelling that is located away from the primary contamination.

Fraction of Time Spent in Farmed Areas: This is the fraction of time that the receptor spends 

outside in agricultural land and pasture land contaminated by irrigation or by atmospheric 

deposition. If any agricultural or pasture land overlies the primary contamination, the time spent 

in that common area should be included in the entry for the agricultural or pasture land and in 

the outdoor time fraction above the primary contamination.

Note: The sum of the time fractions spent indoors and outdoors on the primary contamination 

and in the offsite dwelling site cannot exceed unity. Because of the way the time fractions are 

defined here, it is possible for the sum of all the time fractions of a single individual to exceed 

unity. However, the sum of the time fractions will not exceed 2. (The sum will equal 2 if an 

individual spends all the time outdoors in an agricultural or pasture land that overlies the primary 

contamination.) In addition, the time fractions spent indoors on the primary contamination and 

indoors and outdoors in the offsite dwelling site, and in the farmed areas, cannot exceed unity.

Uncertainty and sensitivity analysis can be performed on any parameter on this form. The user 

must ensure that the combined occupancy limits discussed in the preceding paragraph are not 

violated during uncertainty analysis.
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4.28 Radon Data

Figure 56. Radon Form

The radon model is discussed in Appendix C of the RESRAD (onsite) Manual (Yu et al. 2001).

The radon parameters are activated only when the radon pathway is turned on. The radon 

pathway can be turned on only if a parent of either radon-222 (Rn-222) or radon-220 (Rn-220) is 

present as a contaminant. The wind speed found on the Physical and Hydrological Parameters 

form (Section 4.12), the volumetric water content of the clean cover on the Primary 

contamination form (Section 4.13), and the total porosities in the offsite locations (Sections 4.14 

and 4.15) are also used for the outdoor radon dose component calculation. Uncertainty and 

sensitivity analysis can be performed on any parameter on this form (Figure 56).

Depth of Foundation Below Ground Level: This is the depth from the ground surface to the 

bottom of the basement slab. The default value of −1 indicates that the slab will be placed 

directly on top of the contaminated zone.
96

Onsite Vertical Dimension of Mixing: This is used to define the mixing volume used to 

compute the onsite concentrations of radon, C-14, and H-3.

Building Indoor Area Factor: This is the fraction of the floor area built on the contaminated 

area. Values greater than 1.0 indicate a contribution from walls penetrating the contaminated 

zone. The default value of 0 indicates that the time-dependent area factor is derived from an 

assumed floor area of 100 m2 and the amount of wall extending into the contaminated zone.
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4.29 Carbon-14 Data

Figure 57. Carbon-14 and Carbon-12 Forms

Appendix L of the RESRAD (onsite) Manual contains a description of the C-14 parameters and 

their use in the C-14 model. The vertical dimension of mixing parameter on the Radon Data 

form (Section 4.28) is also used to compute the onsite concentrations of C-14 and H-3.

Uncertainty and sensitivity analysis can be performed on any parameter on these forms (Figure 

57).
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4.30 Tritium (H-3) Data

Figure 58. Tritium Form

Parameters for the tritium model can be input on the tritium form (Figure 58). Appendix L of the 

RESRAD Manual contains a description of the H-3 parameters and their use in the H-3 model. It 

also contains a map of average U.S. humidity values. The vertical dimension of mixing 

parameter on the Radon Data form (Section 4.28) is also used to compute the onsite 

concentrations of C-14 and H-3. Uncertainty and sensitivity analysis can be performed on any 

parameter on this form.
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5 RESULTS

For each deterministic analysis, RESRAD-OFFSITE produces three textual reports and a data 

file that can be viewed by using the RESRAD graphics interface. The first few pages of each 

report list the table of contents of the report. The RESRAD graphics interface provides many

options for viewing the results.

Sensitivity analysis (one-parameter-at-a-time) results are also viewed by using the RESRAD 

graphics interface. Uncertainty analysis results are produced in a report and in a number of data 

files that can be graphed in the uncertainty interface. The contents of the reports are as outlined 

below.

Textual Deterministic Reports

1. Parent Dose Report (.par)

A. Inputs

• Dose conversion factors

• Transfer factors

• Site characteristics

B. Pathway selections

C. Total dose

• At user-specified reporting times

• Peak and time of peak

D. Pathway doses from transformation chain of initially present nuclides

• At user-specified reporting times

E. Guideline information

• Dose/source ratios at user-specified reporting times, attributed to 

initially present nuclides

• Single radionuclide soil guidelines at user-specified reporting times

• Single radionuclide soil guidelines at time of peak dose from nuclide

• Radionuclide soil guidelines at time of peak dose from all nuclides

F. Run-time information

• Execution time

• Convergence failures of numerical integration (groundwater transport)
100

2. Progeny Dose Report (.pro)

A. Pathway doses from nuclides at point of exposure

• At user-specified reporting times

3. Cancer Risk Report (.rsk)

A. Cancer risk slope factors

B. Excess cancer risks

• Attributed to initially present nuclides

• Attributed to nuclides at point of exposure

• Radon and short-lived progeny contributions

Uncertainty and Probabilistic Analysis Reports

1. Dose and Risk Report (.prb)

A. Inputs

• Summary of distribution of each input

B. Minimum, maximum, mean, and standard deviation at reporting times

• Total dose from each initially present nuclide

• Total risk from each initially present nuclide

• Pathway dose from each initially present nuclide

C. Cumulative distribution function

• Peak total dose

• Peak pathway dose

• Peak total risk

• Peak pathway risk

D. Correlation and regression coefficients (if requested by user)

• Peak total dose with inputs

• Peak pathway dose with inputs

• Peak nuclide dose with inputs

• Peak total risk with inputs

• Peak pathway risk with inputs

• Peak nuclide risk with inputs
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2. Probabilistic Input Report (.smp)

A. Input specification

• Distribution of each input 

• RCC

• Warnings of incompatible input correlations

B. Input samples

• Input vectors 

• Rank of input vectors

• Correlation coefficients of raw data

• Correlation coefficients of rank data
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5.1 Report Viewer

Figure 59. Report Viewer

The Report Viewer (Figure 59) is launched automatically at the end of each run to display the 

Parent Dose Report (summary.rep). The Report Viewer may also be accessed at any time from 

the Main Menu, toolbar, DOS-Emulator, or Navigator to view any of the current reports or any 

reports from the past that were saved.

Getting to Report Viewer

• Menu: Click on Select View, Text Output, and then any of the available 

choices: Parent Dose Report, Risk Report, Progeny Dose Report, 

Uncertainty/Probabilistic Dose and Risk Report, Uncertainty/Probabilistic 

Inputs Report, Linear Regression Report, and Area Factors Report.

• Toolbar: Only the Parent Dose Report can be accessed from the toolbar.

Click on the report page icon (the left button on the third cluster).

• DOS-Emulator: Click on the View Output button and then the command 

button corresponding to the desired report.
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• Navigator: Go to the Results tab and click on the command button 

corresponding to the desired report.

Viewing a Previously Saved Report

From within the Report Viewer, click on File and View another File (Ctrl-F) from the Report 

Viewer main menu. Point to the subdirectory where the input files are located. Select the file that 

you want to view. The saved files have the same root name as the input file. Three-character 

extensions identify the seven types of report files as follows:

• af = area factors report,

• par = parent dose report,

• prb = uncertainty and probabilistic dose and risk report,

• pro = progeny dose report,

• reg = regression report,

• rsk = cancer risk report, and

• smp = uncertainty-probabilistic input report.

Figure 60. File Dialog box of Report Viewer

The complete set of files that are saved for a particular input file can be viewed by typing in the 

input file name followed by a period and the wild card character in the view file dialog box

(Figure 60). Some of the other file extensions of interest are as follows:
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• chn = a file listing the transformation threads and principal nuclides for each 

initially present nuclide.

• pds or prk = formatted data file of peak probabilistic dose or risk for each 

simulation, and

• pin = data file of probabilistic samples for each simulation.

Moving Around

• Pages: To go to another page, choose one of the following methods:

− Enter the page number in the page text box and hit Enter.

− Pull down the page list and click on the desired page.

− Advance a page by pressing the “Page Down” key or by clicking on the 

double down arrows.

− Go back a page by pressing the “Page Up” key or by clicking on the 

double up arrows.

• Within a Page: Use scroll bars to position text.

• Between Reports: Click on File and View another File (Ctrl-F) from the 

Report Viewer main menu to view another report. You can also close the 

Report Viewer and go back to the Main Menu to select a different file.

Saving Files

Every time a calculation is run, the previous reports and graphics files are overwritten. The 

results can be saved under different names, which allows for their retrieval later.

• Saving All Files: Click on File and Save All under the Report Viewer main 

menu. This will save all textual reports to files. If the input filename is 

xxxx.rad, the reports will be saved as xxxx.yyy, where the extension yyy 

identifies the report as described in “Viewing a Previously Saved Report” 

above.

• Saving the Open Report: Click on File and Save under the Report Viewer 

main menu. This will prompt the user for a name under which to save the 

currently displayed report.
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Copying Selections

• Copy Highlighted Section: Click on Edit/Copy under the Report Viewer 

main menu. The selected text will be placed on the Windows clipboard and 

can be placed into any document, such as a spreadsheet or word-processed 

text.

• Copy the Current Page: Click on Edit/Select All, followed by Edit/Copy.

Another option is to click on the icon that looks like two pages.

Printing

• Setting up the Printer: RESRAD-OFFSITE uses the standard Windows 

printer. The setup for the printer can be accessed through the 

File/Printer/Setup menu option. Options that can be selected include printer, 

paper size, and orientation.

• Setting up the Report for Printing: Click on the icon that looks like a single 

page to automatically select the best font size that will fit the report to a single 

page width.

• Printing: Select the File/Print menu option or click on the printer icon button.

A dialogue box will appear for printing the whole report, sets of pages, or the 

current highlighted text.
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5.2 Graph Viewer (Deterministic and Sensitivity Analysis)

Figure 61. Graph Viewer

Getting to Graph Viewer 

• Menu: Click on View on the RESRAD-OFFSITE menu, then select 

Deterministic Graphics (Figure 61).

• Toolbar: Click on the middle icon in the third cluster, the one with the button 

prompt saying “View Deterministic Graphics.”

• DOS-Emulator: Click on View Output to bring up the output form. Click on 

Deterministic Graphics.
107

• Windows Navigator: Click on the Results tab, then click on the Deterministic 

Graphics icon.

Choosing from the Plot Selection Pallet

All dose, risk, and concentration data produced by RESRAD-OFFSITE for each radionuclide 

and pathway or media combination are available to the Graph Viewer. Thus a wide choice of 

plots is available. The plots are selected by specifying the following:

• Type (of Plot)

− Dose: Select Dose to view a graphical representation of the radiological 

dose over the user-specified time horizon.

− Concentration: This displays a plot of the concentration of the selected 

radionuclide in various media over the user-specified time horizon.

− Dose/Source Ratio: This displays a graph of the ratio of an individual 

radionuclide’s dose contribution to its initial concentration in soil in the 

primary contamination, over the user-specified time horizon.

− Soil Guidelines: Select Soil Guidelines to view a graph of the initial 

radionuclide concentration in soil that will produce the specified basic 

radiation dose limit at that specific time as a function of time.

− Risk: Select Risk to view a graphical representation of the excess cancer 

risk over the user-specified time horizon.

• Radionuclide

− Summed: This option is available for Dose and Risk plots; it displays the 

dose or risk due to all the radionuclides specified to be present at the site.

− Individual: This option is available for all five types of plots, but its 

definition depends on the type of plot. Select the radionuclide by using the 

drop-down scroll box.

 When used with the concentration plots, it displays the concentration of the 

selected radionuclide (either an initially present nuclide or a progeny) in the 

selected media.

 When used with the other four types of plots, it displays the total quantity due 

to the selected radionuclide (initially present nuclide) and its progeny.

− Individual and Progeny: This option is available for Dose, Dose/Source 

Ratio, and Risk plots. It displays the individual dose, dose-to-source ratio, 

or risk due to the selected radionuclide (initially present nuclide) and each 

of its progeny.

− Individual and Threads: This option is available for Dose, Dose/Source 

Ratio, and Risk plots. It displays the individual dose, dose-to-source ratio, 
108

or risk due to each of the transformation chains of the initially present 

radionuclide.

• Pathways: Options are available for Dose, Dose/Source Ratio, and Risk 

plots.

− Summed: This sums the selected quantity over all pathways and plots 

the sum.

− Components: This plots the selected quantity from each pathway in one 

plot.

− Water Indep./Dependent: This plots two lines on the graph. The first one 

shows the waterborne contribution, and the second one shows the 

airborne and any direct contribution from the selected quantity.

− Individual: This plots a single selected pathway. The pathway is selected 

by using the drop-down scroll box.

• Media: This appears in place of the Pathways options when concentration 

plots are selected. Select the medium by using the drop-down scroll box.

• Sensitivity: This is displayed when a sensitivity analysis is performed.

− Base Case: This shows only the results of the deterministic run.

− Sensitivity to a Parameter: Select a parameter from the drop-down list 

to see the sensitivity of the output to that parameter.

Selecting from the Graph Viewer Menu

• File

− Open: This command is used to open the deterministic graphics data file 

from a previous run. The deterministic graphics data file is stored in the 

same directory as the input files at the end of each run. These files have 

the same root name as their input files but end with the extension .grp.

− New Window: This command displays another Graph Viewer window.

Two plots from the same data file can be viewed. Plots from two different 

graphics data files cannot be viewed in the different windows.

− Save Plot Data for Text Viewer: This command writes the x and y 

values used in the plot that is displayed in columns in an ASCII (American 

Standard Code for Information Interchange) file. A header row is printed 

after every 61 lines, making it easier to view the data over multiple pages.

− Save Plot Data for Graphing: This command writes the x and y values 

used in the plot that is displayed in columns in an ASCII file. The header 
109

row is printed once at the beginning of the file, making it easier to use 

these data in other graphing programs.

− Print: This command is used to produce a hard (paper) copy of the 

current plot.

− Print Setup: This opens a window displaying the list of available printers 

and printing specifications.

− Close Window: When multiple Graph Viewer windows are open, this 

command is used to close an individual window.

− Exit: This closes all Graph Viewer windows.

• Edit

− Copy: This command saves the plot in a metafile. The print screen (Print 

Scrn) key on the keyboard produces a much better quality image.

− Export to Excel: This command opens a new Excel file and transfers the 

x and y values used in the plot. If multiple lines are displayed in the plot, a 

pair of columns is output for each line that is displayed. The first three 

rows contain the plot title, plot footer, and column headers.

• Options: This menu is used to change the appearance of the plot. The 

following choices can be made: display either axis in linear or logarithmic 

scale, display or suppress grid lines, use different colors for different plots or 

use black for all plots, and use the same or different line styles for the 

different plots. This menu is also used to hide or show the prompts for the 

buttons on the toolbar.

• View: This menu is used to view the plot data. The plot data must have been 

saved previously by using the Save Plot Data command described above 

under the first option, File.

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6 ENHANCEMENTS

The influence of each input on RESRAD-OFFSITE predictions can be investigated by using two 

independent features available in the code. The sensitivity analysis option can be used to 

observe the independent influence of each individual parameter. The uncertainty and 

probabilistic analysis option can be used to study the variation in the prediction and the 

importance of each individual parameter when a number of parameters are varied 

simultaneously over their likely range. These analyses are discussed in Sections 6.1 through 

6.3 and in greater detail in Chapter 4 and in Appendix C of NUREG/CR-7127.

6.1 One-Parameter-at-a-Time Sensitivity Analysis

Figure 62. Set Sensitivity Analysis Range Form

Purpose

One-parameter-at-a-time sensitivity analysis is used to study the independent influence of each 

individual parameter on the predicted dose, risk, and concentrations. Each of the selected 

parameters is varied in turn by a factor, which is first higher than its deterministic (base) value, 

and then lower. Thus, two additional runs of the code are performed for each parameter 

selected for sensitivity analysis. Three curves are plotted to show the variation of the predictions 

over time for the three values (low, base, high) of the parameter, while all the other parameters

are held at their base values.
112

Displaying the Sensitivity Analysis Range

• Menu: First click on the input box of the parameter of interest to put it in 

focus. Then click on Form Options on the RESRAD-OFFSITE menu and 

Sensitivity Analysis (F9 key).

• Toolbar: First click on the input box of the parameter of interest to put it in 

focus. Then click on the Set Sensitivity Button (fourth button in the second 

cluster on the toolbar).

• Input Window: First click on the parameter of interest, then press the F9 key.

• Sensitivity Input Summary Bar: The sensitivity input summary bar (shown if 

Sensitivity Input Summary under the View option is checked) will include a 

button for each parameter selected for sensitivity analysis. The title of the 

button includes the variable name, the symbols */, and the factor by which to 

multiply and divide. Right Click on any of these buttons to review, change, or 

remove a sensitivity analysis on the corresponding parameter.

Selecting a Parameter for Sensitivity Analysis

First display the Set Sensitivity Analysis Range form (Figure 62) while the cursor is in the input 

box corresponding to the desired parameter. Then set the multiplication and division factor as 

described below.

Choose one of the options for the multiplication and division factor. The resultant values for the 

two sensitivity runs will be shown at the right along with the base value. If you choose the last 

option, you can enter any value greater than 1 or accept the value of 10. If the selected factor 

causes a parameter value to exceed its bounds, a warning message will be displayed with the 

option to set the factor to the maximum allowable value. If the base value specified for any 

variable selected for sensitivity analysis is changed, the sensitivity button corresponding to that 

factor should be revisited to ensure that the values for the sensitivity analysis will still be within 

the bounds.

Click on the OK button to include the parameter in the sensitivity analysis. A button for this 

parameter will be added on the sensitivity input summary bar, and the parameter will be 

selected for sensitivity analysis.
113

Removing a Parameter from Sensitivity Analysis

If a parameter has already been selected for sensitivity analysis, the button corresponding to it 

will be on the sensitivity input summary bar. Either right-click on that button, or left-click and 

choose No Analysis to remove the sensitivity analysis. Clicking on Cancel will not remove the 

parameter from the sensitivity analysis in this case.

If the parameter has not yet been selected, simply click Cancel on the Set Sensitivity Analysis 

Range form to disregard the information in the form.

Viewing Results of Sensitivity Analysis

Sensitivity analysis results are shown only in a graphic format, not in any textual report. Launch 

the deterministic Graph Viewer after performing a sensitivity analysis on the selected 

parameters; the Sensitivity option will be displayed at the bottom of the plot selection pallet 

(Section 5.2). Select a parameter from the drop-down box to see the sensitivity of the output to 

that parameter.

More information on performing sensitivity analysis using RESRAD-OFFSITE is available in 

Chapter 4 and in Appendix C of NUREG/CR-7127.
114

6.2 Uncertainty and Probabilistic Analysis

Figure 63. Uncertainty and Probabilistic Analysis Form

Purpose

Uncertainty and probabilistic analysis is used to determine the variation in the predictions (dose, 

risk, or media concentrations) due to the uncertainty in the values of some parameters and the 

probabilistic nature of other parameters. It can also be used to identify the input parameters that 

are responsible for the major part of the variation in the output (Multiparameter Sensitivity 

Analysis, Section 6.3). Then the resources can be focused on reducing any uncertainty in those 

parameters in order to most efficiently reduce the variation in the predicted dose, risk, or media 

concentration.
115

Selecting an Input Parameter for Uncertainty and Probabilistic Analysis

• Menu: First click on the input box of the parameter of interest to put it in 

focus. Then click on Form Options and Uncertainty/Probabilistic Analysis 

(F8 key) (Figure 63).

• Toolbar: First click on the input box of the parameter of interest to put it in 

focus. Then click on the Uncertainty/Probabilistic Analysis button (farthest 

button on the right in the second cluster on the toolbar; it has a ±? symbol 

on it).

• Input Window: Press the F8 function key while the focus is on the input 

parameter to be included for uncertainty or probabilistic analysis.

The distribution of the selected variable is specified in the Parameter distributions tab 

(Section 6.2.1) of the Uncertainty and Probabilistic Analysis interface form.

Displaying the Uncertainty and Probabilistic Analysis (Interface) Form

• Menu: Click on View and then Uncertainty/Probabilistic interface (Ctrl-F8).

This displays the form and sets the user preference to always display the 

form when the RESRAD-OFFSITE interface is launched.

The methods just described (Selecting an Input Parameter for Uncertainty and Probabilistic 

Analysis) will also display the form if it is not already visible. They are not included here because 

they also select the input that is in focus at the time they were invoked for uncertainty or 

probabilistic analysis.

The Uncertainty and Probabilistic Analysis form currently has one tab (Related inputs) under 

development and six active tabs as follows.

1. Parameter distributions: The uncertainty in the value of an input or the 

probabilistic nature of an input is specified in the form of a probabilistic 

distribution on this tab.

2. Sample specifications: This tab is used to specify how the probabilistic 

input sets will be generated from the distributions specified in the previous 

tab.
116

3. Input rank correlations: This tab accepts the specification of correlations 

between pairs of uncertain/probabilistic inputs if the appropriate choice is 

made in the Sample specifications tab.

4. Output specifications: This tab describes the different types of probabilistic 

display and analysis options that are available for the various outputs and is 

used to specify whether the component doses, risks, and concentrations for 

each realization of a probabilistic run need to be saved. It is also used to 

specify the desired output-input correlation and regression coefficients.

5. Step-by-step analysis: This tab allows the analysis to be carried out in 

sequence and provides an option to view the results of each step before 

proceeding to the next. It also allows viewing of the probabilistic graphics 

from a previous analysis.

6. Post run regression: This tab is used to obtain a specific selection of outputinput correlation and regression coefficients.

These six tabs are described more fully in Sections 6.2.1 through 6.2.6.
117

6.2.1 Parameter Distributions Tab

Figure 64. Parameter Distributions Tab of the Uncertainty and Probabilistic Analysis 

Form

All the input parameters that are selected for uncertainty and probabilistic analysis are listed in 

the Variable Description box at the left of the Parameter Distributions tab (Figure 64). Click on 

any of the entries in that box to display the distribution specified for that input parameter. When 

an input parameter is selected for uncertainty and probabilistic analysis, it is added to the 

bottom of the list. The uncertainty in the value of the input parameter or the probabilistic nature 

of the input parameter can be specified on the right side of the tab. This is done as follows:

1. Select the type of distribution from the drop-down box.

2. Enter the statistics necessary to define the selected distribution in the input 

boxes below the drop-down box.

3. Save the distribution and its statistics by clicking on the Update Parameter 

stats and distribution button, the Previous parameter arrow, or the Next 

parameter arrow.

4. You can cancel any changes made to the distribution type or statistics if they 

have not yet been saved by clicking on the Restore Parameter stats and 
118

distribution button or by simply clicking on a different input parameter in the 

list on the left.

Clicking on the Help button on this tab displays the Help on Statistical distributions form for the 

selected distribution. This Help form (Figure 65) displays the probability density function of the 

selected distribution in the brown box on the right side of the form. Interrelationships among 

alternative forms for specifying the same distribution, or the definitions of the distribution 

statistics, are also included in the same box, where appropriate. Any conditions that must be 

satisfied by the distribution statistics are in the gray box at the bottom of the form. The 

probability density function of the distribution is sketched on the left side of the form. The 

bounds of the input parameter are indicated by two red (vertical) lines if they fall within the 

sketch. If the red lines are visible, the statistics for the distribution need to be changed to confine 

the distribution within these bounds.

Figure 65. Help on Statistical Distributions Form
119

6.2.2 Sample Specifications Tab

Figure 66. Sample Specification Tab of the Uncertainty and Probabilistic Analysis Form

This tab (Figure 66). specifies how the distributions specified in the previous tab are sampled 

and how the samples for the different inputs are to be combined to produce the set of inputs

The frame on the right side of the tab describes the purpose and effect of each of the items on 

this tab.

• Number of Observations: This is the number of values that will be sampled 

from the distribution of each input parameter specified in the Parameter 

distributions tab. This must exceed the number of input parameters if 

correlations are specified between inputs or if regression statistics are to be 

produced. The accuracy of the probabilistic predictions can be improved by 

increasing the number of observations.

• Sampling Technique: The code offers a choice of two sampling techniques: 

Latin hypercube sampling (LHS) or Monte Carlo. In the LHS technique, the 

distribution is divided into equally probable segments, equal in number to the 

desired number of observations. Then a value is picked at random from each 
120

segment according to the probability density function within that segment.

This ensures that the sample covers the entire range of the distribution, even 

when the number of samples is relatively small. In the Monte Carlo technique, 

the desired observations are each picked at random from the entire 

distribution according to the probability density function. When the number of 

samples is small, the sampled values do not represent the distribution as well 

as the values obtained by using the LHS technique.

• Random Seed: Both sampling techniques choose the sample value from the 

appropriate part of the distribution at random according to the probability 

density function. The sampling code has a random number generator to 

produce the pseudo-random numbers needed to do the random sampling.

The random number generator produces a random number on the basis of 

the seed it receives. It also increments the seed to the next integer, every 

time a random number is generated. Thus, the sequence of random numbers 

that is generated to obtain the sample can be exactly reproduced if the same 

starting seed is used again. The Random Seed input is the starting seed; it 

allows the code to reproduce the same set of probabilistic inputs should there 

be a need to rerun the same analysis at a later time on a different computer.

• Grouping of Observations: After the code obtains the required number of 

samples for each input parameter, it produces the probabilistic set of inputs.

Each element of the set of inputs will contain one sample from each of the 

input parameters. The code offers two choices on how the samples from 

each input parameter are combined to make the set of inputs: (1) Random 

grouping or (2) Correlated or Uncorrelated grouping. If it is necessary to have 

correlations between some of the inputs, or if it is necessary to ensure that 

there is no correlation between some of the inputs (i.e., zero correlation), the 

correlated grouping must be used. 

• Number of Repetitions: This is the number of times the analysis needs to 

be repeated in order to obtain a measure of the accuracy of the probabilistic 

predictions. Increasing the number of observations increases the accuracy of 

the probabilistic predictions, but a measure of the accuracy can be obtained 

only if the analysis is repeated. The closeness of the results, or the lack 

thereof, is an indication of the accuracy, or lack of accuracy, of the 

predictions.
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6.2.3 Input Rank Correlations Tab

Figure 67. Input Rank Correlations Tab of the Uncertainty and Probabilistic Analysis 

Form

This tab (Figure 67) becomes active to accept input only if the Correlated or uncorrelated 

grouping option on the Sample specifications tab has been chosen. Correlations are specified 

between the ranks of the inputs, not the raw values of the inputs. The pair of inputs that are to 

be correlated are chosen from the two dropdown boxes, and the RCC is specified in the 

corresponding input box, all on the frame at the left. The Update Correlation table button on the 

right frame saves the information in the correlation table at the left. Correlations that were saved 

can be deleted by first clicking on the corresponding line in the table at the left and then clicking 

on the Remove correlation button on the right. The correlations can also be edited by clicking on 

the appropriate row in the table and then changing the value of the RCC. The revised 

correlation must be updated for it to take effect. A pair of uncorrelated inputs (i.e., a pair with a 

zero correlation coefficient) need not be specified in the table because the correlation between 

any pair of inputs that are not included in the table is implicitly set to zero in the sampling code.
122

6.2.4 Output Specifications Tab

Figure 68. Output Specifications Tab of the Uncertainty and Probabilistic Analysis Form

The frame at the top left of this tab (Figure 68) shows the five categories of dose and risk for 

which probabilistic results can be obtained. Four of the five categories are always active; the 

user can choose whether or not to save in a file the dose, risk, and concentration at each 

graphical time for each realization (each observation of each repetition). The execution time 

increases when this option is checked. Clicking on the checkbox displays, in the frame at the 

right, the various forms of output that are available for each category. The frame at the lower left 

is used to select the output-input correlation coefficients to be computed during the analysis.

Alternatively, these can be unselected before the run, and only the desired correlation and 

regression coefficients can be computed after the main computational code is run. This is done 

by using the Post run regression tab.
123

6.2.5 Step-by-Step Analysis Tab

Figure 69. Step by Step Analysis Tab of the Uncertainty and Probabilistic Analysis Form

This tab (Figure 69) fulfills three main functions: (1) permits a step-by-step approach to 

performing probabilistic analysis, (2) serves as the starting point for viewing the probabilistic 

graphics, and (3) permits viewing of previously saved results. The different command buttons 

become active at the appropriate juncture.

The Generate input samples (LHS) command is the only button that is visible for a newly 

created uncertainty/probabilistic input file. Clicking on the button launches the probabilistic 

sample generating code (LHS). The remaining three buttons in the upper active (first) row 

become active when the input samples have been generated. The Generate output samples 

(RESRAD-O) button is also activated at this time. The three buttons in the first row are used to 

view the corresponding plots and to check the statistics of the input distributions. These plots 

can be viewed to confirm that the samples accurately represent the specified distribution and to 

visualize any correlations that were specified between the inputs.

Clicking on the Generate output samples button launches the main computational code. The 

execution time can be significant for probabilistic analysis. While some simple cases might run 
124

in a few minutes, a typical analysis can run for hours. An estimate of the run time is displayed in 

the run time feedback form (Run form; Section 7.4). The remaining command buttons become 

active when the output samples have been produced.

The other three buttons in the third row are used to view the probabilistic plots pertaining to the 

output. These are discussed in more detail in the following paragraphs. The buttons on the 

fourth row produce temporal plots. The left button produces temporal plots and statics for the 

total dose and corresponding plots for the component doses, risks, and concentration have not 

yet been developed. Instead, the right button will produce a deterministic plot file for each of the 

realizations; these can then be viewed in the deterministic Graph Viewer. Clicking on the 

Generate output-input correlation and regression coefficients button (bottom row) displays the 

Post run regression tab.

Figure 70. Step by Step Analysis Tab of the Uncertainty and Probabilistic Analysis Form 

when a Previously Executed Input File is Opened

Plots from previous runs can also be viewed from this tab by opening the corresponding input 

file. When a preexisting input file is opened, the code checks for an indication that the file has 

been executed previously. If it has and if probabilistic results are available, the Preexisting 

Output button is displayed at the bottom right of the tab (Figure 70). Click on this button to load 

the probabilistic input and output into the interface memory. This usually takes some time, so a 
125

Please Wait bar is displayed to ask for the patience of the user. The seven view plot buttons can 

then be used to view the three input plots (scatter plots of input against input, histogram of input, 

and CDF [cumulative distribution function] of input), the three output plots (CDF of output, 

scatter plots of output against input, and scatter plots of output against output) and the temporal 

plots for total dose. Input-output regression analysis can also be performed.

Figure 71. The CDF of Output view of the Probabilistic/Uncertainty Graphics Output

The CDF of the output (Figure 71) can be used to obtain any desired percentile of the output 

(dose or risk). The value of the percentile can be obtained by keying in the desired percentile in 

the gray box in the X-axis frame on the right side of the Probabilistic/Uncertainty outputs screen.

This frame also displays the mean and the standard deviation of the output. Error ranges are 

shown, where appropriate, after a plus/minus symbol (±). (If the error range is less significant 

than the number of significant figures in the output, it will not be shown.) The value of the 

percentile for the different repetitions can also be displayed by clicking on the location of the 

desired percentile on the plot. This value is shown in the yellow tooltip that appears below the 

cursor. The tooltip disappears when the cursor moves away from the box. The up and down 

arrow buttons can be used to cycle over all the probabilistic outputs. One or more repetitions 

can be omitted from the plot if needed to improve the clarity. At the bottom right of the screen, 

the Display graph button must be depressed to show the changes made in the Plot Settings 

frame. This form can be resized by expanding the sides or corners.
126

Figure 72. Scatter Plot of Output against Input view of the Probabilistic/Uncertainty 

Graphics Output

The scatter plots of output against input are helpful in identifying the input parameters that have 

a significant influence on the output, especially when there are few significant input parameters.

However, as the case illustrated in Figure 72 shows, it is not easy to visually pick out the 

important parameters when they are masked by the compounding effects (interference) of other 

equally important input parameters. The important parameters can be identified by using the 

regression coefficients, as was done in the case illustrated above. 
127

Figure 73. Scatter Plot of Output against Output view of the Probabilistic/Uncertainty 

Graphics Output

Scatter plots of output against output (Figure 73) are useful for identifying the pathways and 

nuclides that make a significant contribution to the variation in the dose or risk. They can also 

point to the importance of common parameters that affect the significant pathways.
128

Figure 74. Probabilistic Temporal Plots

The temporal plot shows the variation of the mean, median, and one other user specifiable 

percentile of the total dose (dose summed over nuclides and pathways) with time (Figure 74).

The plots for all repetitions can be displayed together as shown above to see the variation 

among repetitions; plots of each repetition can be displayed for clarity. The coordinates of any 

location on the plot can be displayed in a highlighted box by moving the cursor to that point. The 

data from the plots for that corresponding year can be displayed by clicking the mouse; the data 

for each of the repetitions will be shown in the box at the lower right of the form.
129

6.2.6 Post Run Regression Tab

Figure 75. Regression Analysis Tab of the Uncertainty and Probabilistic Analysis Form

This tab (Figure 75) is used to perform regression analysis between the desired outputs and the 

probabilistic inputs after RESRAD-OFFSITE main computational code is run. Check the desired 

outputs (dose and/or risk and the pathways) and click on the Determine correlation and 

regression coefficients button. The results are appended to the probabilistic dose and risk 

report. A separate regression report with the probabilistic inputs sorted in decreasing order of 

influence is displayed in the Report Viewer.
130

6.3 Multiparameter Sensitivity Analysis

Figure 76. Multi-Parameter Analysis View of Parameter Distributions Tab of the 

Uncertainty and Probabilistic Analysis Form 

Multiparameter sensitivity analysis can be performed using the uncertainty feature (Figure 76) 

by allowing more than one parameter to vary at the same time. A parameter can be selected for 

this analysis by pressing Shift-F8 when the parameter has focus. The selected parameters can 

have a uniform distribution with a half range of 50%, 25%, 10%, 5%, or 0.1% of the deterministic 

value on either side of the deterministic value, or a log-uniform distribution ranging from 1/10 to 

10, 1/5 to 5, 1/3 to 3, 1/2 to 2, or 1/1.001 to 1.001 times the deterministic value (see Section 6.2,

Uncertainty and Probabilistic Analysis). The sensitivity of the dose or risk to the parameters is 

given by the standardized regression coefficient or the standardized rank regression coefficient 

(Figure 77).

More information on performing sensitivity analysis using RESRAD-OFFSITE is available in 

Chapter 4 and in Appendix C of NUREG/CR-7127.
131

Figure 77. Regression Output
132

Figure 78. Output against Input Scatter plot Showing the Variation of Output with One 

Input at Different Values of Another Input

The uncertainty analysis feature can also be used to see the variation of dose over the range of 

one parameter at various levels of another parameter. The scatter plot of output against input is 

useful in seeing this variation and the interaction among the inputs, as shown in Figure 78. The 

coordinates of any point on the figure can be found by moving the cursor to that point; clicking 

the mouse will display the crosshairs. This is useful in finding the peak of a curve.
133

7 HELP

Various levels of help are available in RESRAD-OFFSITE: 

• Application Help Form: A help file that is accessible from the code gives a 

description of each input and explains how the parameter is used in the code.

• Message Log (View - OUTPUT.FIL) Form: A message log that is produced 

during the execution of the computational code is useful for debugging if the 

code should terminate before completion.

• RESRAD Website: The RESRAD Website has documents that relate to the 

RESRAD family of codes. The latest code is available for downloading from 

the site. The About RESRAD-OFFSITE form from the Help menu of the code 

contains a link to the RESRAD Website and e-mail address of the RESRAD 

team.

• Run Time Feedback Form: This gives information about the progress of the 

computation and a dynamic estimate of the run time for probabilistic cases.

• PDF Versions of the User’s Guide, the User’s Manual, and other 

Documents: This guide, the technical manual, and the other reports that are 

listed in the menu can be accessed in PDF form. 
134

7.1 Application Help (on Input Parameters)

Figure 79. Context Sensitive Help

Getting Help

• Menu: When the desired parameter is in focus, select context help from the 

Help submenu (press Alt-H, then press C) (Figure 79).

• Input Window: Press the F1 key.

• From within the Help window:

− Click on the desired parameter name on the Contents tab.

− Search for a word in the Search tab.

The Help file has a simple description of the input parameter selected by the user and how the 

parameter is used in the code. For a more detailed description of the parameter and for 

information on how to obtain site-specific values, please refer to the RESRAD Data Collection 

Handbook.
135

7.2 Message Log

Figure 80. Message Log Generated by the Computational Code

Getting to the Log

From the Main menu, choose View and Message Log. The message log (Figure 80) will also be 

displayed if the computational code encounters an error.

Interpreting the Log

This file lists the progress of the computational code as it completes each phase of calculation 

and begins the next phase. If the computational code ended before completing the calculations, 

the file will contain an error message that should be reported to the RESRAD team.

Reporting Problems

The e-mail address for communicating about problems and asking questions is resrad@anl.gov.
136

7.3 Website

Figure 81. RESRAD Website

Getting to the Home Page

Type the RESRAD Website address, http://www.evs.anl.gov/resrad, in your Web browser or 

click on the link to it in the code. The links are found on the About RESRAD-OFFSITE form 

(press Alt-H, then press A) and in the Help tab of the Navigator window.

The RESRAD Website contains the following (Figure 81):

• Descriptions of the RESRAD family of codes;

• Downloadable version of the latest code;

• Table of current versions and release status;

• Information on upcoming training workshops and pictures from previous 

workshops;

• List of version releases and dates, along with a short description of the 

modifications included in the updated versions;

• E-mail contact; and

• Documents related to the RESRAD family of codes.
137

Getting to a RESRAD Document

Figure 82. A portion of the Documents Page of the RESRAD Website

Go to the Documents page of the Website (Figure 82). These documents can be downloaded to 

your computer. Presently there are 45 documents available.
138

7.4 Run Time Feedback Form

Figure 83. Run Time Feedback Form

The colored highlighted information bar displays the progress of the computation (Figure 83).

The information bar cycles through yellow, blue, and green as it checks the progress of the 

computational code. For a deterministic run, both UNC (uncertainty) and SENS (sensitivity) will 

equal zero. If a sensitivity analysis is being performed, the SENS counter will show the index of 

the current sensitivity run; there will be two sensitivity runs for each input parameter selected for 

sensitivity analysis. The UNC counter displays the index of the current uncertainty/probabilistic 

run. The remainder of the information bar shows the code module being executed; the primary 

contaminant being considered; the transport layer or location, if appropriate; and, in the case of 

groundwater transport, the nuclides entering and leaving the transport layer and the current 

intermediate time. The frequency at which this information bar is updated can be changed in the 

Title form (Section 4.1). Frequent updates can increase the run time.

The time that elapsed since the run command was executed is shown in the first line below the 

information bar. This is followed by two more lines that are displayed only when an 

uncertainty/probabilistic analysis is performed. The second line shows the estimated calculation 

time. It includes the time that has elapsed and the amount of time the code is likely to continue 

running. This line should stabilize after the first few probabilistic runs. The stability of the 

calculation time is an indication of the reliability of the estimated time to completion, which is 

shown in the third line. 

While frequent updates from the computational program gives the user a good idea of what the 

code is currently doing and how long it is likely to take before the run ends, this can come at the 

cost of increased run time. For probabilistic runs it may be advantageous to shut off message 

writing by the computational code, as described in Update Progress of Computation Message in 

Section 4.1. The interface will still be able to display the UNC counter of the index of the current 

uncertainty/probabilistic run, and will give estimates of calculation time and time to completion 

based on the size of the output files generated.
139

8 REFERENCES

Eckerman, K.F., et al., 1988, Limiting Values of Radionuclide Intake and Air Concentration and

Dose Conversion Factors for Inhalation, Submersion, and Ingestion, EPA-520/1-88-020, 

Federal Guidance Report No. 11, prepared by Oak Ridge National Laboratory, Oak Ridge, 

Tenn., for U.S. Environmental Protection Agency, Office of Radiation Programs, Washington, 

D.C.

Eckerman, K.F., et al., 1999, Cancer Risk Coefficients for Environmental Exposure to

Radionuclides, EPA-402-R-99-001, Federal Guidance Report No. 13, prepared by Oak Ridge

National Laboratory, Oak Ridge, Tenn., for U.S. Environmental Protection Agency, Office of

Radiation Programs, Washington, D.C.

EPA (U.S. Environmental Protection Agency), 2001, “Risk Assessment, Radionuclide Table

Slope Factors Download Area,” April 16. Available at http://www.epa.gov/radiation/heast/

download.htm.

ICRP (International Commission on Radiological Protection), 1983, Radionuclide

Transformations: Energy and Intensity of Emissions, ICRP Publication 38, Annals of the ICRP,

Vols. 11−13, Pergamon Press, New York, N.Y.

ICRP, 1996, Age-Dependent Doses to Members of the Public from Intake of Radionuclides:

Part 5 ⎯ Compilation of Ingestion and Inhalation Dose Coefficients, ICRP Publication 72,

Annals of the ICRP, Vol. 26(1), Pergamon Press, New York, N.Y.

Yu, C., A.J. Zielen, J.-J. Cheng, D. LePoire, E. Gnanapragasam, S. Kamboj, J. Arnish, 

A. Wallo III, W.A Williams, and H. Peterson, 2001, User’s Manual for RESRAD Version 6, 

ANL/EAD-4, Argonne National Laboratory, Argonne, Ill., July.

Yu, C., E. Gnanapragasam, J.-J. Cheng, and B. Biwer, 2006, Benchmarking of RESRADOFFSITE: Transition from RESRAD (onsite) to RESRAD-OFFSITE and Comparison of the 

RESRAD-OFFSITE Predictions with Peer Codes, ANL/EVS/TM/06-3, DOE/EH-0708, May.

Yu, C., E. Gnanapragasam, B.M. Biwer, S. Kamboj, J.-J. Cheng, T. Klett, D. LePoire, 

A.J. Zielen, S.Y. Chen, W.A. Williams, A. Wallo, S. Domotor, T. Mo, and A. Schwartzman, 2007, 
140

User’s Manual for RESRAD-OFFSITE Version 2, ANL/EVS/TM/07-1, DOE/HS-0005, 

NUREG/CR-6937, June.

Yu, C., E.K. Gnanapragasam, J.-J. Cheng, S. Kamboj, and S.Y. Chen, 2013, Revised New 

Source Term Model for the RESRAD-OFFSITE Code Version 3, ANL/EVS/TM/11-5, 

NUREG/CR-7127, prepared by Argonne National Laboratory for U.S. Nuclear Regulatory 

Commission, June.
APPENDIX A:

OVERRIDING THE SOURCE TERM AND SPECIFYING 

RELEASES FROM PRIMARY CONTAMINATION

A-1

APPENDIX A:

OVERRIDING THE SOURCE TERM AND SPECIFYING RELEASES FROM PRIMARY 

CONTAMINATION

Three cases are discussed: (1) nuclides with no progeny, (2) nuclides with progeny in a simple 

single transformation chain, and (3) nuclides with progeny in a transformation chain with 

branches. For each case, the output from the RESRAD-OFFSITE source models is presented 

first to illustrate the input that RESRAD-OFFSITE needs. This is followed by illustrations of 

specific input.

A.1 Nuclides with No Progeny

This section applies to nuclides with no radioactive progeny and to nuclides whose progeny all 

have transformation half-lives of less than the cutoff half-life. Figures A.1 and A.2 are examples 

of the source files generated by RESRAD-OFFSITE for such nuclides for the traditional 

RESRAD first-order leach rate model. Plots of these data are shown in Figures A.3 through A.6. 

Figures A.7 and A.8 illustrate the releases to groundwater generated by RESRAD-OFFSITE for 

other release options.

A.1.1 RESRAD-OFFSITE Source Module Output

SFSIN.DAT in Figure A.1 tabulates the concentration of the nuclide in the primary contamination 

as a function of time. RESRAD-OFFSITE lists this information for every graphical time specified 

for the run. The leftmost column lists the graphical times in years; the second column lists the 

concentration, in pCi/g, at the corresponding graphical time. 

CZTHICK3.DAT in Figure A.1 tabulates the thicknesses of the three layers in the area of 

primary contamination (clean cover, contaminated mixing layer, and the unmixed primary 

contamination) and the composite modification factor for the concentration of nuclides in the 

mixing zone. These are described in Section 2.2.3 of the RESRAD-OFFSITE manual (Yu et al. 

2007); the composite modification factor is the ratio between the concentrations of the nuclide in 

the mixing layer and in the primary contamination. The leftmost column lists the graphical times; 

the second column lists the composite modification factor for the concentration of nuclides in the 

mixing zone at each graphical time. The last three columns list the thicknesses of the clean 

cover, contaminated mixing layer, and unmixed primary contamination respectively, in meters, 

at the graphical times.
A-2

AQFLUXIN.DAT in Figure A.2 tabulates the rate of release of the nuclide from the lower 

boundary of the primary contamination due to leaching as a function of time. The leftmost 

column lists the graphical times; the second column lists the rate of release of the nuclide, in 

pCi/yr, at the corresponding graphical time. 

FIGURE A.1 Examples of SFSIN.DAT and CZTHICK3.DAT Files Created by the Source 

Term Model of RESRAD-OFFSITE under the Traditional RESRAD Leach 

Model
A-3

FIGURE A.2 Examples of AQFLUXIN.DAT, AIFLUXIN.DAT, and SWFLUXIN.DAT Files 

Created by the Source Term Model of RESRAD-OFFSITE under the 

Traditional RESRAD Leach Model
A-4

FIGURE A.3 Temporal Profile of Activity in the Primary Contamination under the 

Traditional RESRAD First-Order Leach Rate Release Model

FIGURE A.4 Temporal Profile of Release to Groundwater under the Traditional 

RESRAD First-Order Leach Rate Model
A-5

FIGURE A.5 Temporal Profile of Release to Atmosphere under the Traditional 

RESRAD First-Order Leach Rate Model

FIGURE A.6 Temporal Profile of Release to Surface Erosion under the 

Traditional RESRAD First-Order Leach Rate Model
A-6

FIGURE A.7 Temporal Profile of Release to Groundwater under the Equilibrium 

Desorption Release Model

FIGURE A.8 Temporal Profile of Release to Groundwater under the First-Order 

Leach Rate with Transport Release Model
A-7

AIFLUXIN.DAT in Figure A.2 tabulates the rate of release of the nuclide from the mixing layer 

into the atmosphere as a function of time. The leftmost column lists the graphical times; the 

second column lists the rate of release of the nuclide, in pCi/yr, at the corresponding graphical 

time. 

SWFLUXIN.DAT in Figure A.2 tabulates the rate of release of the nuclide from the mixing layer 

due to erosion by runoff as a function of time. The leftmost column lists the graphical times; the 

second column lists the rate of release of the nuclide, in pCi/yr, at the corresponding graphical 

time. 

A.1.2 Checklist of Steps to Override the RESRAD-OFFSITE Source Model

The procedure to override the source module of RESRAD-OFFSITE and to specify the releases 

and concentration in the contaminated zone is illustrated using a hypothetical and not 

necessarily realistic example. Suppose that the following source term information is to be 

specified in this example. 

1. The receptor is far enough offsite that the direct exposure from the primary 

contamination is insignificant. It is therefore not necessary to specify the 

concentration in the primary contamination (SFSIN.DAT), or the thicknesses 

of the various zones in the primary contamination (CZTHICK3.DAT).

2. For illustrative purposes, assume that the releases to groundwater, to the 

atmosphere, and to surface runoff to be input are as given in Table A.1. 

These inputs are illustrative of the care needed when modeling with input 

fluxes that change rapidly and where there are few data points to be input.
A-8

TABLE A.1 Release to Be Input to RESRAD-OFFSITE

Release to 

Groundwater

Release to 

Atmosphere Release in Soil to Surface Runoff

Time 

(yr)

99Tc 

(pCi/yr)

Time 

(yr)

99Tc 

(pCi/yr)

Time 

(yr) 

99Tc 

(pCi/yr)

Soil 

(g/yr)

0 to 5 0 0 to 2 0.1 0 to 3 0 0

5 50 2 0.5 3 0 0

6 100 3 4 4 5 0.5

7 100 4 5 5 4 0.45

9 75 5 4 6 2 0.3

10 50 6 2 7 and 

beyond

0 0

12 10 9 and 

beyond

0

15 and 

beyond

0

1. Set up the input file for the nuclide (with no decay chain) in RESRAD-OFFSITE and run it to 

produce the RESRAD-OFFSITE generated source output files SFSIN.DAT, CZTHICK3.DAT, 

AQFLUXIN.DAT, AIFLUXIN.DAT, and SWFLUXIN.DAT.

2. Place the source data in the appropriate files. For this example, the data in Table A.1 need to 

replace the information in the files that were generated by RESRAD-OFFSITE in Step 1 above. 

Open AQFLUXIN.DAT in a simple text editor (e.g., Notepad); the file will be in the RESRADOFFSITE root directory. Replace the content of that file with the information in the first two 

columns of Table A.1 while retaining the format of the original file. Save the file back in the 

RESRAD-OFFSITE directory; it would be good practice to also save the file in the “UserFiles” 

subdirectory of RESRAD-OFFSITE under an appropriate name, say, “Inputfilename.AQF.” The 

resulting file is shown in Figure A.9.

Do the same with the other input file; only AIFLUXIN.DAT and SWFLUXIN.DAT in this example, 

as direct onsite exposure is not being modeled in this example case. These files are also shown 

in Figure A.9.
A-9

FIGURE A.9 Input Files AQFLUXIN.DAT, AIFLUXIN.DAT, and SWFLUXIN.DAT Created to 

Specify the Releases of This Example to RESRAD-OFFSITE

3. Open the input file using a simple text editor (e.g., Notepad). The variables NAIFLXT, 

NAQFLXT, NSFST, and NSWFLXT are set at two locations of the input file as shown in 

Figure A.10. They are the number of data points to be read from the input files AIFLUXIN.DAT, 

AQFLUZIN.DAT, SFSIN.DAT, and SWFLUXIN.DAT, respectively. NSFST is also the number of 

data points to be read from the file CZTHICK3.DAT. These are all set to zero by default to 

signify that no inputs need to be read and that the releases are to be calculated by RESRADOFFSITE. A positive integer value needs to be specified for at least one of these variables in 

order to shut off the source term calculations of RESRAD-OFFSITE and to have it read the 

specified releases. The values of NAIFLXT, NAQFLXT, NSFST, and NSWFLXT are set to 

reflect the number of points being specified in the respective files (8, 9, 0, and 6, respectively, in 

this example). Save this file and close the text editor.

4. Open in RESRAD-OFFSITE the input file that you just modified and saved in the text editor 

in Step 3. Run this file in RESRAD-OFFSITE.

5. Compare the source term output files SFSIN.DAT, CZTHICK3.DAT, AQFLUXIN.DAT, 

AIFLUXIN.DAT, and SWFLUXIN.DAT that RESRAD-OFFSITE created by interpolating between 

the values that you specified. Compare the temporal release plots with the fluxes that you 

specified to ensure that the number of computational time points being used in RESRADOFFSITE is sufficient to accurately model the specified input. Figures A.11 through A.13 show 

these comparisons for three different RESRAD-OFFSITE runs with 64, 128, and 512 

computational time points for this example case. These plots illustrate the need to choose a 

large number of computational time points in cases in which the input flux experiences rapid 

change in a short time period. There are other constraints, such as the need to represent with 

sufficient precision the temporal variation of flux across all the transportation zone boundaries, 

that also indicate the need for a large number of intermediate time points. Note that the 

RESRAD-OFFSITE code will overwrite the flux files SFSIN.DAT, CZTHICK3.DAT, 

AQFLUXIN.DAT, AIFLUXIN.DAT, and SWFLUXIN.DAT every time it is executed. Thus, if you 

want to rerun a case in which you are specifying the releases from the source, you will need to 

copy back the information from the source release files that you created and saved in the 

“Userfiles” subdirectory.
A-10

FIGURE A.10 RESRAD-OFFSITE Input File Showing the Locations Where the Numbers of 

Time Points at which the Different Releases Are to Be Read Are Specified 

(Default Case at the Top, Current Example at the Bottom)
A-11

FIGURE A.11 Comparison of the Input Flux Specified in This Example Case for 

AQFLUXIN.DAT and the Flux Interpolated by RESRAD Using 

Different Numbers of Computational Time Points
A-12

FIGURE A.12 Comparison of the Input Flux Specified in This Example Case for 

AIFLUXIN.DAT and the Flux Interpolated by RESRAD Using 

Different Numbers of Computational Time Points
A-13

FIGURE A.13 Comparison of the Input Flux Specified in This Example Case for 

SWFLUXIN.DAT and the Flux Interpolated by RESRAD Using 

Different Numbers of Computational Time Points
A-14

FIGURE A.14 Automatic Selection of All Progeny with a Half-Life Greater 

Than the Cutoff Half-Life, When a Nuclide Is Specified to Be Initially

Present in the Contamination

A.2 Nuclides with Progeny in a Simple Transformation Chain

Two examples are used to illustrate the format of the RESRAD-OFFSITE source term output. 

First, consider the case of a contamination where only thorium-230 (230Th) is initially present. 

When this isotope is selected in RESRAD-OFFSITE, the code automatically adds its long-lived 

progeny as seen in Figure A.14. Which progeny are added for explicit consideration of fate and 

transport depend on the cutoff half-life selected by the user (Figure A.15). The three files that list 

the releases computed by the source term module of RESRAD-OFFSITE are shown in 

Figure A.16. The first column in each of those three files lists the times at which calculations are 

performed. The second column lists the release of 230Th at each of the times. The third, fourth, 

and fifth columns list the release of the long-lived progeny at each of those times in the order in 

which they occur in the transformation chain; radium-226 (226Ra), lead-210 (

210Pb), and 

polonium-210 (210Po).

In the second example, 230Th and its long-lived progeny are initially present at the same 

concentration (Figure A.17). The file listing the release to groundwater, AQFLUXIN.DAT, is used 
A-15

to illustrate the output in this case (Figure A.18). The first column again lists the times at which 

calculations are performed. RESRAD-OFFSITE analyzes the initially present nuclides in 

alphabetical order: 210Pb, 210Po, 226Ra, and 230Th. The second column therefore contains the 

release of 210Pb at each of the times followed by columns of data for any progeny of 210Pb at 

each of the times. Thus the third column lists the release of 210Po that was derived from the 

transformation of the initially present 210Pb. Next, the code computes and lists the release of the 

nuclides in the transformation chain of the second initially present nuclide in the list, namely 

210Po. There being no long-lived progeny for 210Po, the code lists a single column of data for the 

release of the initially present 210Po in column four. Next, the code computes the releases of the 

nuclide in the transformation chain of the third initially present nuclide, 226Ra. The fifth, sixth, and 

seventh columns of data list the release of initially present 226Ra, the 210Pb that was derived from 

the initially present 226Ra, and the 210Po that was derived from the initially present 226Ra. The 

release of the initially present 230Th and the 226Ra, 210Pb, and 210Po that were derived from the 

initially present 230Th are listed in columns 8, 9, 10, and 11, respectively. The code does this in 

order to be able to attribute the dose at any time back to the initial nuclide that gave rise to the 

progeny that produced the dose. This is necessary if a cleanup guideline is to be computed. If, 

however, the purpose is to make predictions of the exposure, then it is not necessary to 

separately keep track of the progeny, say, 210Pb, that resulted from the different initially present 

parent nuclides. In that case, flag the code with only the first member of the transformation 

chain as being initially present and combine the release of each progeny from all initially present 

nuclides in one column of data. Then the data can be entered in fewer columns: four in the first 

example rather than 10 in the second example.
A-16

FIGURE A.15 Selection of Cutoff Half-Life

FIGURE A.16 Source Term Output Files for Case with Only 230Th Initially Present
A-17

FIGURE A.17 Long-Lived Progeny Are at the Same Concentration as 

the Parent in the Initial Contamination
A-18

FIGURE A.18 Source Term Output Files for Case in which 230Th and Its Long-Lived 

Progeny Are Initially Present

A.3 Nuclides with Progeny in a Transformation Chain with Branches

This example illustrates the format of the output of the source term modules of RESRADOFFSITE for nuclides with branches within a transformation chain. A good illustration of the 

complexity of the output is americium-242m (242mAm). Figure A.19 shows the nuclides that are 

included by the code when 242mAm is selected with a cutoff half-life of 30 days. According to the 

chain file created when the input file is saved in RESRAD-OFFSITE, eight threads of the 

transformation chain of 242mAm are considered in this case (Figure A.20). The fraction of 242mAm 

that follows each thread of the transformation chain and the nuclides in that thread are also 

shown in Figure A.20. 

The source term output files generated by RESRAD-OFFSITE contain 35 columns of data, one 

each for the long-lived nuclides in the eight transformation threads. The first three 

transformation threads start with 242mAm, which transforms via short-lived 242Am to curium-242 

(

242Cm). The first transformation thread contains the fraction of 242Cm that then undergoes 
A-19

spontaneous fission. The release of 242mAm and 242Cm that follows this transformation thread 

are listed in the second and third columns of the source module output files. The second thread 

is the fraction of 242mAm that follows the same route as the first thread to 242Cm; the 242Cm in this 

thread transforms to plutonium-238 (238Pu), which then undergoes spontaneous fission. The 

releases of 242mAm, 242Cm, and 238Pu that follow this second transformation thread are listed in 

the fourth, fifth, and sixth columns of the source module output files, respectively. The third 

thread is thefraction of 242mAm that follows the same route as the second thread to 238Pu; the 

thread then continues through uranium-234 (234U), 230Th, and 226Ra and a web of short-lived 

nuclides, 210Pb and its short-lived progeny bismuth-210 (210Bi), and finally to 210Po. The releases 

of 242mAm, 242Cm, 238Pu, 234U, 230Th, 226Ra, 210Pb, and 210Po that follow this transformation thread 

are listed in the seventh through fourteenth columns of the source module output files. The 

fourth, fifth, and sixth threads start with 242mAm, which transforms via short-lived 242Am to 242Pu 

and are similar to the first three threads, with 242Pu taking the place of 242Cm, and 238U taking the 

place of 238Pu. Thus, columns 15 and 16 show the release of 242mAm and 242Pu that follows the 

fourth transformation thread; columns 17, 18, and 19 show the release of 242mAm, 242Pu, and 

238U that follows the fifth transformation thread; and columns 20 through 27 show the release of 

242mAm, 242Pu, 238U, 234U, 230Th, 226Ra, 210Pb, and 210Po that follows the sixth transformation 

thread. The last two threads start with 242mAm, which transforms via short-lived neptunium-238 

(

238Np) to 238Pu; from that point, these two threads correspond to threads two and three. 

Columns 28 and 29 list the release of 242mAm and 238Pu, which follows the seventh 

transformation thread; columns 30 through 36 show the release of 242mAm, 238Pu, 234U, 230Th, 

226Ra, 210Pb, and 210Po, which follow the eighth transformation thread.

FIGURE A.19 Progeny of 242mAm Modeled Explicitly by RESRAD-OFFSITE 

When a Cutoff Half-Life of 30 Days Is Specified
A-20

If a user is providing the releases calculated by a different code, the flux input files to RESRADOFFSITE will need to have the temporal release information about each nuclide in each thread 

in the order specified in the chain file. Depending on the transformation chain, it may be 

possible to combine some of the threads and place the combination in one column and to put 

zeros in the other columns of the same nuclide. This will need to be done after verifying that 

there are no further branches beyond that nuclide and after ensuring that the dose factors for 

the nuclides in the columns being combined are the same.

FIGURE A.20 Chain File Generated by RESRAD-OFFSITE Showing the Branches and 

Threads of the 242mAm Transformation Chain
A-21

A.4 Reference for Appendix A

Yu, C., E. Gnanapragasam, B.M. Biwer, S. Kamboj, J.-J. Cheng, T. Klett, D. LePoire, 

A.J. Zielen, S.Y. Chen, W.A. Williams, A. Wallo, S. Domotor, T. Mo, and A. Schwartzman, 2007, 

User’s Manual for RESRAD-OFFSITE Version 2, ANL/EVS/TM/07-1, DOE/HS-0005, 

NUREG/CR-6937, June.

APPENDIX B: 

COMPUTING AREA FACTORS FOR 

OFFSITE EXPOSURE SCENARIOS 

B-1 

APPENDIX B:

COMPUTING AREA FACTORS FOR

OFFSITE EXPOSURE SCENARIOS

The area factor is the ratio of the dose from the whole (large or wide) area of primary 

contamination to the dose from a small (hot spot or elevated activity) area within the large (wide) 

area. The small (elevated activity) area is referred to as the elevated measurement comparison 

(EMC) area in the Multi-Agency Radiation Survey and Site Investigation Manual (MARSSIM) 

(2000). The area factor can be used in conjunction with MARSSIM applications to determine the 

Derived Concentration Guideline Level (DCGL) for a small EMC area (i.e., DCGLEMC). In 

MARSSIM terminology, the DCGL for the large (wide) area is called DCGLW. Because the 

DCGL is inversely proportional to the corresponding dose, the area factor is equivalent to the 

quotient of DCGLEMC divided by DCGLW, as shown in Equation B.1. The area factors are 

especially useful in field applications for quick determination of DCGLEMC, which is simply the 

product of the area factor and the DCGLW: 

AAAAAAAA FF FFFFFF = 

DDDDDDDD ffff ff wwh oo aa aa pp ii ii cc cccc cc cc cc

DDDDDDDD ffff ff aa aa ee ee aa

= 

DDDDDDDDEEEEEE

DDDDDDDDWW

(B.1)

RESRAD-OFFSITE code Version 3 provides users with a way to obtain a set of area factors for 

an offsite receptor scenario, prior to the post cleanup survey. Because neither the sizes nor the 

locations of any small areas of elevated measurement are known prior to the final survey, the 

code uses the probabilistic analysis feature to analyze a number of small areas of elevated 

measurement, each of a different size and each possibly at a different location within the wide 

area. The first step is to prepare an input file just as in the case of a regular RESRAD-OFFSITE 

run. The layout of the site is specified in the site layout form or in the map interface, and siteappropriate values are input for all of the variables in the RESRAD-OFFSITE interface. Then, 

the “Generate Area Factors” command is chosen in the File menu to display the Area Factors 

form (Figure B.1). The user can then specify parameters related to area factor calculations. The 

X dimension of the small area of elevated contamination is always sampled. The Y dimension of 

the small area of elevated contamination can either be sampled or it can be made proportional 

to the X dimension. If the Y dimension is to be sampled, the correlation between the samples of 

the X and Y dimensions can be specified. The location of the small area of elevated 

contamination can be fixed at the center of the primary contamination, or it can be allowed to 

move within the confines of the original primary contamination.
B-2

FIGURE B.1 Area Factors Form—Default Options

B.1 Range of the X Dimension of the Small Area of Elevated Contamination

By default, the X dimension of the small area of elevated contamination will be obtained by 

sampling a triangular distribution skewed to the low end ranging from 1/50 to 1 times the 

X dimension of the primary contamination. The user can change the lower and upper limits; 

however, the upper limit may not exceed the X dimension of the primary contamination; that is, 

the X dimension of the small area of elevated contamination cannot be larger than the 

X dimension of the primary contamination (wide area).

B.2 Range of the Y Dimension of the Small Area of Elevated Contamination

By default, the Y dimension of the small area of elevated contamination is set to be proportional 

to the X dimensions of the small area of elevated contamination. The default proportionality 

constant is the ratio of the Y dimension of the primary contamination to the X dimension of the 

primary contamination (Figure B.1). The user may change the proportionality constant; however, 

the code will not then check to ensure that the resulting Y dimension of the small area of 

elevated contamination is less than the Y dimension of the primary contamination.

Alternatively, the Y dimension can be sampled in the same manner as the X dimension. If this 

option is chosen (Figure B.2), by default the Y dimension will be sampled from a uniform 

distribution ranging from 1/50 to 1 times the Y dimension of the primary contamination. The user 
B-3

can change the lower and upper limits; however, again, the upper limit may not exceed the 

Y dimension of the primary contamination. In this case, the user can specify the rank correlation 

coefficient between the X and Y dimensions of the small area of elevated contamination; the 

default value of 0.99 will produce results that are similar to the default proportionality option. A 

negative rank correlation coefficient would simulate small areas of elevated contamination that 

are elongated in either the X or Y directions.

B.3 Distribution of the X and Y Dimensions of the Small Area of Elevated Contamination

Three options are available for the distribution of the dimensions of the small area of elevated 

contamination: (1) triangular distribution skewed to the high end, (2) uniform distribution, and 

(3) triangular distribution skewed to the low end. Option 1 (i.e., triangular distribution skewed to 

the high end) will result in uniform spacing of the sampled contamination area. This result can 

be seen from the cumulative distribution function of the area that was produced under this 

option (see Figure B.3). Option 2 (i.e., sampling the dimensions uniformly) will result in a 

distribution of the contamination area that is skewed to the lower end. The distribution of the 

sampled area will be skewed even more toward the low end if Option 3 (i.e., triangular 

distribution that is skewed to the low end) is selected. Either Option 2 or Option 3 would be 

appropriate if the number of small areas of elevated contamination is likely to be low and a user 

desires to sample a larger number of small areas.

FIGURE B.2 Area Factors Form—Option to Specify the Range of the 

Y Dimension of the Small Area of Elevated Contamination 
B-4

FIGURE B.3 Distribution of Area of the Small Area of Elevated Contamination under 

Three Distributions Options for Sampling the Dimensions of the Small 

Area of Elevated Contamination: Triangular Skewed to the High End 

(top), Uniform (bottom left), and Triangular Skewed to the Low End 

(bottom right)
B-5

B.4 Location of the Center of the Small Area of Elevated Contamination

There are two choices for the location of the center (or centroid) of the small area of elevated 

contamination: it can be fixed at the center of the primary contamination, or it can be allowed to 

vary. The fixed option will produce a tighter curve between the dose and the small area of 

elevated contamination. Under the variable option, the small area of elevated contamination is 

constrained to be within the primary contamination. Thus, the center has to lie within a rectangle 

with dimensions that are the difference between the corresponding dimensions of the primary 

contamination and the small area of elevated contamination. The code samples two unit uniform 

distributions and uses those samples to locate the center of the small area of elevated 

contamination. A sample value of zero for the X location would place the left edge of the small 

area of elevated contamination on the left boundary of the primary contamination; a unit value 

would place the right edge of the small area of elevated contamination on the right boundary of 

the primary contamination. Likewise, a sample value of zero for the Y location would place the 

lower edge of the small area of elevated contamination on the lower boundary of the primary 

contamination; a unit value would place the top edge of the small area of elevated 

contamination on the upper boundary of the primary contamination. Because the calculated 

dose will vary with the location of the small area of elevated contamination, the first option 

(centers fixed) could produce area factors that are higher than reasonable, whereas the second 

option (moving centers) will produce conservative area factors.

B.5 Number of Points on the Dose—Area Plot

This specifies the number of times the distribution of the dimensions of the small area of 

elevated contamination is to be sampled. The default value is 1,000. A smaller value can be 

used if the dose–area relationship is expected to be in a tight band or a single curve. This result 

would be the case if the Y dimension of the small area of elevated contamination is set to be 

proportional to the X dimension and the center is fixed. A larger value might be required if the 

dose–area relationship is expected to be in the shape of a wide band. This result could be the 

case when both dimensions of the small area of elevated contamination are sampled and/or the 

location of these small areas of elevated contamination was allowed to vary.

B.6 Generate Dimensions

The Generate Dimensions command button is used to generate the layout—dimensions and 

location—of each sample of small area of elevated contamination and the offsite transport 

distances from each sample of small area of elevated contamination to the offsite receptor 

locations. The Generate Dimension command must be clicked after the user does the following: 

specifies the limits and type of distribution for the X dimension of the small area of elevated 

contamination, chooses the method of determining the Y dimension and specifies the required 

values for that method, selects the desired location option for the centers of the small areas of 

elevated contamination, and sets the number of samples. This command button first launches 

the probabilistic sampling code to sample all of the specified distributions. That information is 

then read by the interface, which uses the sampling results to develop the relationships for the 

offsite transport distances. Three types of plots of the dimension that were generated can be 
B-6

viewed before proceeding to generate the dose from each small area of elevated contamination: 

scatter plots, histograms, and cumulative distribution functions. These plots are used to verify 

that the desired layout and transport distances have been generated. The Generate Dose-Area 

Plot command button becomes active after the layout and transport distances have been 

generated (Figure B.4).

B.7 Generate Dose—Area Plot

This command launches the computational code of RESRAD-OFFSITE to process the inputs for 

each of the sampled small areas of elevated contamination to generate the dose from each of 

those small areas of elevated contamination. A scatter plot of dose against the area of elevated 

contamination and a text report of area factors are displayed at the end of the run. Four sample

plots, obtained by using four options for sizing and locating the small area, for three different 

radionuclides (i.e., cesium-137 [Cs-137], plutonium-239 [Pu-239], and technetium-99 [Tc-99]) 

are shown in Figures B.5 through B.7. The four options are case (a) the Y dimensions of the 

small areas of elevated contamination are proportional to the X dimensions of the small areas of 

elevated contamination, and the centers of the small areas of elevated contamination coincide 

with the center of the whole contamination; case (b) the Y dimensions of the small areas of 

elevated contamination are proportional to the X dimensions, and the small areas of elevated 

contamination are located within the whole contamination but are not constrained to be 

concentric; case (c) the Y dimensions of the small areas of elevated contamination are sampled 

and paired with the samples of the X dimension at a specified correlation, and the centers of the 

small areas of elevated contamination coincide with the center of the whole contamination; and 

case (d) the Y dimensions of the small area of elevated contamination are sampled and paired 

with the samples of the X dimension at a specified correlation, and the small area of elevated 

contamination is located within the whole contamination but is not constrained to be concentric.
B-7

FIGURE B.4 Area Factors Form—Generate Dose-Area Plot Command 

Button Activated

B.8 Table of Area Factors

The area factor of a nuclide is the ratio of the activity concentration of the nuclide in a small area 

of elevated contamination located within the primary contamination, DDDDDDDDEEEE , to the activity 

concentration of the nuclide in the whole primary contamination, DDDDDDDDWW, both of which result in 

a peak total dose equal to the basic radiation dose limit to the same offsite receptor. Dose is 

linearly related to the activity concentration in the primary contamination under the RESRADOFFSITE model. Thus, the area factor can be computed by dividing the RESRAD-OFFSITE 

predicted peak nuclide dose from the entire primary contamination by the RESRAD-OFFSITE 

predicted peak nuclide dose from a small area of elevated activity when both areas are modeled 

at the same activity concentration:

AAAAAAAA FF FFFFFF = DDDDDDDDEEEEEE

DDDDDDDDWW

= DDDDDDDD pp uu aa ffff ff pp aa cc cccc cc cc cc

DDDDDDDD pp uu aa ffff ff aa aa ee ee aa (B.2)

The dose versus area plots for case (a) in Figures B.5, B.6, and B.7 are all single curves, 

whereas the plots for cases (b) and (d) are scattered over a wide band. The plots for case (c) 
B-8

are similar to case (a), with some scatter that is noticeable at higher doses. In cases (a) and 

(c), the small area of elevated contamination is constrained to be concentric with the primary 

contamination. In cases (b) and (d), the small area of elevated contamination is constrained to 

be within the primary contamination, but it does not have to be concentric with it. The dose from 

the small area of elevated contamination will be influenced by its location relative to the receptor 

for almost all exposure pathways. For example, in Figure B.5, where the direct external 

exposure pathway dominates, a small area of elevated contamination that is located closer to 

the receptor will subject the receptor to a greater dose than one that is located farther away, all 

other conditions being equal. Similarly in Figure B.6, where the atmospheric transport is the 

dominant exposure pathway, a small area of elevated contamination that is located in an 

unfavorable location with respect to atmospheric stability, wind speed, and distance will subject 

the receptor to a greater dose than one that is located at a favorable location, all other 

conditions being equal. Likewise in Figure B.7, where groundwater transport is the dominant 

exposure pathway, a small area of elevated contamination that has considerable overlap of flow 

lines with the source of water will subject the receptor to a greater dose than one that has little 

overlap of flow lines, all other conditions being equal. The transport distance will also influence 

the dose depending on the relative effects of ingrowth, decay, and dispersion. In cases (a) and 

(b), the small area of elevated contamination is constrained to be similar in shape to the primary 

contamination. In cases (c) and (d), the small area of elevated contamination is of a different 

shape, because its two dimensions are sampled separately and paired according to a userspecified correlation. The small area of elevated contamination will more closely resemble the 

shape of the primary contamination if the dimensions are directly correlated to a high degree 

(rank correlation coefficient of almost 1). The dose from the small area of elevated 

contamination will be influenced by its shape for almost all exposure pathways; the relationship 

between shape and dose is complex.
B-9

FIGURE B.5 Scatter Plot of Dose against Area of Contamination for Cs-137 Where the 

Direct External Exposure from the Primary Contamination is the Dominant 

Pathway. Top left: Case (a), Y dimension is proportional to the X dimension; 

the center of the small area of elevated contamination is located at the 

center of the primary contamination. Bottom left: Case (b), Y dimension is 

proportional to the X dimension; the small area of elevated contamination is 

located anywhere within the primary contamination. Top right: Case (c), X 

and Y dimensions are highly correlated (rank regression coefficient 0.99); 

the center of the small area of elevated contamination is located at the 

center of the primary contamination. Bottom right: Case (d), X and 

Y dimensions are highly correlated (rank regression coefficient 0.99); the 

small area of elevated contamination is located anywhere within the primary 

contamination.
B-10

FIGURE B.6 Scatter Plot of Dose against Area of Contamination for Pu-239 for Which 

Atmospheric Transport Is the Dominant Route of Exposure. Top left: Case 

(a), Y dimension is proportional to the X dimension; the center of the small 

area of elevated contamination is located at the center of the primary 

contamination. Bottom left: Case (b), Y dimension is proportional to the X 

dimension; the small area of elevated contamination is located anywhere 

within the primary contamination. Top right: Case (c), X and Y dimensions 

are highly correlated (rank regression coefficient 0.99); the center of the 

small area of elevated contamination is located at the center of the primary 

contamination. Bottom right: Case (d), X and Y dimensions are highly 

correlated (rank regression coefficient 0.99); the small area of elevated 

contamination is located anywhere within the primary contamination.
B-11

FIGURE B.7 Scatter Plot of Dose against Area of Contamination for Tc-99 for Which 

Groundwater Transport Is the Dominant Route of Exposure. Top left: Case 

(a), Y dimension is proportional to the X dimension; the center of the small 

area of elevated contamination is located at the center of the primary 

contamination. Bottom left: Case (b), Y dimension is proportional to the X 

dimension; the small area of elevated contamination is located anywhere 

within the primary contamination. Top right: Case (c), X and Y dimensions 

are highly correlated (rank regression coefficient 0.99); the center of the 

small area of elevated contamination is located at the center of the primary 

contamination. Bottom right: Case (d), X and Y dimensions are highly 

correlated (rank regression coefficient 0.99); the small area of elevated 

contamination is located anywhere within the primary contamination.
B-12

Thus, the area factor depends not only on the size of the small area of elevated measurement 

but also on its shape and its location within the primary contamination. Because neither the 

dimensions nor the location of any potential small area of elevated contamination are known 

prior to the final site survey, the area factor table generated by RESRAD-OFFSITE must be that 

for the most detrimental location and dimensions. The code will be better able to find the most 

detrimental location if a sufficiently large number of simulations are performed. The code groups 

the simulations (the default is 1,000 simulations) into 20 intervals based on the area of the small 

area of elevated contamination. Then the code determines the simulation within each interval for 

which the dose/area ratio is the greatest. This method generally allows the code to find the 

20 points from the simulations that are closest to the upper boundary of the dose-area curve. 

The areas and doses of these 20 simulations are used to generate the area factor text report.

The RESRAD-OFFSITE code calculates area factors, and the corresponding small areas are 

output to the file named “AreaFactorText.REP” in the RESRAD-OFFSITE directory. A copy of 

this file is saved as “inputfilename.AF” to the directory where the input file is saved. This file 

contains a list of up to 21 pairs of areas and area factors for each radionuclide analyzed; the 

20 from the probabilistic run and the whole area deterministic run. The area factors for different 

radionuclides are listed on separate pages of the text report. Figures B.8 through B.10 show the 

text reports derived from the information shown in the scatter plots in Figures B.5 through B.7. 

These area factors are for the specific scenario analyzed. They are derived on the basis of 

pathways selected and parameter values used for that particular case. Therefore, for different 

scenarios, the calculated area factors will most likely be different. The user must check the area 

factor table to see whether the number of simulations was sufficient for the code to determine 

the upper boundary of the scatter plot. One way to do this is to check whether the area factors 

are increasing as the area decreases. If they do not, the user could rerun the analysis with a

larger number of simulations.
B-13

FIGURE B.8 Sample of Area Factor Text Report for Cs-137. Top left: Case (a), Y 

dimension is proportional to the X dimension; the center of the small area of 

elevated contamination is located at the center of the primary 

contamination. Bottom left: Case (b), Y dimension is proportional to the X 

dimension; the small area of elevated contamination is located anywhere 

within the primary contamination. Top right: Case (c), X and Y dimensions 

are highly correlated (rank regression coefficient 0.99); the center of the 

small area of elevated contamination is located at the center of the primary 

contamination. Bottom right: Case (d), X and Y dimensions are highly 

correlated (rank regression coefficient 0.99); the small area of elevated 

contamination is located anywhere within the primary contamination.
B-14

FIGURE B.9 Sample of Area Factor Text Report for Pu-239. Top left: Case (a), Y 

dimension is proportional to the X dimension; the center of the small area of 

elevated contamination is located at the center of the primary 

contamination. Bottom left: Case (b), Y dimension is proportional to the X 

dimension; the small area of elevated contamination is located anywhere 

within the primary contamination. Top right: Case (c), X and Y dimensions 

are highly correlated (rank regression coefficient 0.99); the center of the 

small area of elevated contamination is located at the center of the primary 

contamination. Bottom right: Case (d), X and Y dimensions are highly 

correlated (rank regression coefficient 0.99); the small area of elevated 

contamination is located anywhere within the primary contamination.
B-15

FIGURE B.10 Sample of Area Factor Text Report for Tc-99. Top left: Case (a), Y 

dimension is proportional to the X dimension; the center of the small area of 

elevated contamination is located at the center of the primary 

contamination. Bottom left: Case (b), Y dimension is proportional to the X 

dimension; the small area of elevated contamination is located anywhere 

within the primary contamination. Top right: Case (c), X and Y dimensions 

are highly correlated (rank regression coefficient 0.99); the center of the 

small area of elevated contamination is located at the center of the primary 

contamination. Bottom right: Case (d), X and Y dimensions are highly 

correlated (rank regression coefficient 0.99); the small area of elevated 

contamination is located anywhere within the primary contamination.
B-16

The radionuclide-specific area factor for radionuclide i, AAAAAAAA FF FFFFFF ii, can be used with the wide 

area, radionuclide-specific DDDDDDDDWW

ii to quickly estimate a conservative value for the small area 

DDDDDDDDEEEE

ii during the final survey using Equation B.3:

DDDDDDDDEEEE

ii = AAAAAAAA FF FFFFFF ii × DDDDDDDDWW

ii (B.3)

The location and dimension-specific value of the small area DDDDDDDDEEEE

ii can be obtained after the 

final survey by running RESRAD-OFFSITE in the deterministic mode using the information 

obtained during the final survey. If there are multiple radionuclides in the contaminated area, the 

sum of fractions rule can be used to determine whether the dose criterion is exceeded or not.

B.9 Reference for Appendix B

MARSSIM, 2000, Multi-Agency Radiation Survey and Site Investigation Manual (MARSSIM), 

NUREG-1575, Rev. 1, EPA 402-R-97-016, Rev. 1, DOE/EH-0624, Rev. 1, Aug.






NUREG/CR-7189 User’s Guide for RESRAD-OFFSITE