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CCC-0522 VARSKIN 3 V3.1.0.

VARSKIN 3 V3.1.0, Dose Calculation for Skin Contamination, with Sadde Input Generator

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1. NAME OR DESIGNATION OF PROGRAM

VARSKIN 3 V3.1.0

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2. COMPUTERS
To submit a request, click below on the link of the version you wish to order. Only liaison officers are authorised to submit online requests. Rules for requesters are available here.
Program name Package id Status Status date
VARSKIN 3 V3.1.0 CCC-0522/05 Arrived 02-NOV-2009

Machines used:

Package ID Orig. computer Test computer
CCC-0522/05 PC Windows
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3. DESCRIPTION OF PROGRAM OR FUNCTION

VARSKIN 3 calculates the radiation dose (gamma and beta) to skin from radioactive contamination of skin or protective clothing. Varskin 3 Version 3.1.0 corrects a programming error in earlier versions of Varskin 3 that occurred when calculating the percent of electronic equilibrium established for the photon dose model. In general, the correction will result in lower doses calculated for radionuclides that emit high-energy photons, especially at shallow skin depths. Although this correction makes photon dose calculations more accurate, it still assumes that the photon source is a point source; and build up as a function of depth is not modeled. Subsequent versions of Varskin will take into account distributed sources and build up. The NRC is sponsoring a further enhancement to replace the existing photon dose algorithm, develop a quality assurance program for the beta dose model, and correct technical issues reported by users. To facilitate that enhancement, we encourage you to contact NRC (http://www.nrc.gov/about-nrc/regulatory/research/contact-us-varskin.html).

 

VARSKIN 3 is significantly easier to learn and use than VARSKIN Mod 2 and includes numerous corrections and enhancements that are noted in the User Manual. The default area for skin dose calculations was changed to 10 cm2 to conform to recent regulatory guidance. The backscatter correction and gamma dose models were upgraded. The input data file for VARSKIN Mod 2 was modified to reflect current physical data, to include the contribution to dose from internal conversion and Auger electrons, and to reflect a correction for low-energy electrons. In addition, the computer code SADDE (Scaled Absorbed Dose Distribution Evaluator) Mod 2, is incorporated into Varskin 3, thus eliminating the need for additional input from the user.

 

VARSKIN3 calculates the dose to 10 cm2 as a default for comparison to the 50 rad limit and also contains the capability of calculating the dose to other areas, including 1 cm2, to evaluate an exposure against the eye dose limit. The dose is computed at any depth in skin or in a volume of skin from point, disk, cylindrical, spherical, slab (rectangular), and syringe sources. Doses from multiple sources can be computed. A help file that includes all of the information from the NUREG document in addition to a tutorial has also been added to the code package.

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4. METHODS

VARSKIN 3 uses improved algorithms for calculating skin dose that take advantage of the increased power of modern personal computers that improve the overall accuracy of the calculations. Source density is reset to 0.001 g/cm3 when point and 2-D models are used for calculations. The backscatter correction model has been expanded to include 3-D sources and is applied regardless of the dose-averaging area. The minimum distance between the source and target was reduced from 0.27 micro-meter to a value of 0.01 micro-meter. Sixty radial dose calculation points are used on the target area instead of 26 points used in VARSKIN Mod 2. Once the 60-point distribution is calculated, the distribution is evaluated at 10,000 points to increase the reliability of the calculation. VARSKIN 3 evaluates the dose at 50 depths for volume-averaged doses instead of 20 points. Once the 50 point distribution is calculated, the distribution is evaluated over 10,000 points to increase the accuracy and eliminate oscillating results. VARSKIN 3 calculates the backscatter correction factor at each of the 50 depths in the volume averaged dose distribution. In VARSKIN 3, the capability of adding multiple radionuclides was eliminated and a more accurate method of creating library files was incorporated. An improved gamma dose model was incorporated into VARSKIN 3 that calculates the gamma dose to any area up to 10 cm2. BETADATA.DAT is no longer used as the input file for VARSKIN 3. Each user builds a library that contains only the radionuclides of interest to that user. The new data files contain physical data for the average energy, maximum energy, and yield based on data generated by the computer code NUCDECAY (Oak Ridge National Laboratory, 1995, distributed by RSICC as DLC-172), which uses data published in ICRP 38 (1983). Further information in the library files includes data for gamma dose calculations and contributions from internal conversion and Auger electrons.

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5. RESTRICTIONS ON THE COMPLEXITY OF THE PROBLEM

Note that VARSKIN 3 cannot accurately address the lack of charged particle equilibrium. See the User Manual for details on restrictions and comments above.

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6. TYPICAL RUNNING TIME

Run times for VARSKIN 3 vary from a few seconds to several minutes. The code is interactive.

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7. UNUSUAL FEATURES OF THE PROGRAM

UNUSUAL FEATURES OF THE PROGRAM

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9. STATUS
Package ID Status date Status
CCC-0522/05 02-NOV-2009 Masterfiled Arrived
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10. REFERENCES
  • R. J. Traub, W. D. Reece, R. I. Scherpelz, and L. A. Sigalla: Dose Calculation for Contamination of the Skin Using the Computer Code VARSKIN," NUREG/CR-4418, PNL-5610, Pacific Northwest Laboratory (August 1987).

  • J. W. Poston and D. M. Busche: Software Review: VARSKIN-MOD1, Health Physics 58(5), 665.

  • W. D. Reece, S. Miller, and J. Durham: SADDE (Scaled Absorbed Dose Distribution Evaluator), NUREG/CR-5276, PNL-6761 (January 1989).

  • J. S. Durham: Errata for NUREG/CR-5873, VARSKIN MOD 2 and SADDE MOD 2: Computer Codes for Assessing Skin Dose from Skin Contamination, Health Physics Society's Newsletter, 10, 31-32 (October 1994).

  • J. S. Durham: Further Errata for NUREG/CR-5873, VARSKIN MOD 2 and SADDE MOD 2, Health Physics Society's Newsletter, 12, 18 (December 1994).

CCC-0522/05, included references:
- J. S. Durham:
VARSKIN 3: A Computer Code for Assessing Skin Dose from Skin Contamination,
NUREG/CR-6918 (2006)
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11. HARDWARE REQUIREMENTS

VARSKIN 3 was tested at RSICC on a Pentium IV running Windows XP with Service Pack 3.0.

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12. PROGRAMMING LANGUAGE(S) USED
Package ID Computer language
CCC-0522/05 FORTRAN, VISUAL BASIC
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13. SOFTWARE REQUIREMENTS

VARSKIN 3 was developed under the Windows operating system on personal computers. Microsoft Visual Basic 6 (for the user interface) and Lahey Fortran 7.1 compilers were used to create the executables which are included in the package.

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14. OTHER PROGRAMMING OR OPERATING INFORMATION OR RESTRICTIONS

Varskin 3 is not designed for installation on a network. Attempts to install the code on a network have been unsuccessful. QA documents and source files are included on the distribution CD but will not be copied to your hard drive by the installer.

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15. NAME AND ESTABLISHMENT OF AUTHORS

Contributed by:
                Radiation Safety Information Computational Center
                Oak Ridge National Laboratory
                Oak Ridge, Tennessee, USA

 

Developed by:   Center for Nuclear Waste Regulatory Analyses
                Southwest Research Institute, San Antonio, TX, USA

 

                U.S. Nuclear Regulatory Commission, USA

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16. MATERIAL AVAILABLE
CCC-0522/05
Readme.txt
Fortran and Basic source files
Windows executables
built-in data libraries
on-line help
QA documents
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17. CATEGORIES
  • G. Radiological Safety, Hazard and Accident Analysis

Keywords: beta-ray, contamination, energy deposition, kernels, radiation doses.