History of the RSAC-7 Project

RSAC was originally developed and written in assembly language (MAP) for the IBM 7044/44 in 1966 by R. L. Coates and N. R. Horton for support of the Advanced Test Reactor dose consequence calculations. In 1968, a FORTRAN version of the program was prepared by L. C. Richardson. Since 1968, RSAC has undergone substantial revision.

In 1973, RSAC-2 was issued by D. R. Wenzel (Wenzel 1973) to:

  • add input and output options
  • change the inhalation dose calculations (lung and gastro-intestinal tract)
  • change the numerical integration methods for cloud gamma dose calculations
  • change the gamma-ray buildup factor model
  • revise radionuclide yields and half-lives in the standard library
  • refine output format for ease of reading
  • reduce computer memory requirements.

In 1982, RSAC-3 was issued (Wenzel 1982) to:

  • add a fifty-mile population dose calculation
  • use the U.S. Nuclear Regulatory Commission (NRC) Regulatory Guide 1.109 for ingestion dose calculations
  • use the International Commission for Radiological Protection (ICRP) Lung Dynamics Model for inhalation dose calculations
  • use the Dolphin and Eve Gastro-intestinal Tract Model
  • improve error detection.

After undergoing an extensive verification and validation, RSAC-4 (Wenzel 1990) was enhanced and issued in 1990 to:

  • convert the program to FORTRAN 77
  • execute RSAC-4 on a personal computer
  • use internal dose conversion factors from DOE/EH-0071 and external dose-rate conversion factors from DOE/EH-0070
  • add dose summary tables
  • add an ingestion dose model for an acute release
  • increase the number of organs in the dose calculations
  • include water immersion dose calculations
  • program calculated plume rise for either jet or buoyant plume
  • revise fission yields and half-lives
  • add radionuclides to the standard library
  • update the photon data library
  • enhance error diagnostics
  • include verification and validation necessary to meet the additional requirements for software imposed by ASME-NQA-1, “Quality Assurance Program Requirements for Nuclear Facilities.”

In 1994, RSAC-5 (Wenzel 1994) was issued to:

  • add an option to calculate cloud-gamma doses expressed in external dose equivalent
  • add a variable particle size option for inhalation dose calculations
  • resolve the over depletion for ground level releases during stable meteorology that was observed in earlier versions of RSAC
  • add a reflective meteorological model to better model diffusion below the mixing depth
  • include additional radionuclides to more accurately model the U-235 fission chain
  • add a dose summing option
  • incorporate a simplified notation for radionuclide identification
  • include a capability to read radionuclide inventories from external files
  • correct errors observed in earlier versions of RSAC for the finite-plume model integration for cloud-gamma dose calculations and large plumes
  • add meteorological diffusion using Pasquill-Gifford parameters
  • include an option to simulate the release of fission products from an operating reactor
  • update forage and vegetation yields
  • include an option to read ingestion transfer parameters from an external file
  • refine the model for ingestion dose calculations from an acute release.

After major modifications, RSAC-6 was released in 2001 to:

  • add radionuclides to the program library
  • use internal dose conversion factors from Federal Guidance Report (FGR)-11 and external dose-rate conversion factors from FGR-12
  • calculate doses at distances of less than 100 meters
  • correct minor errors identified in the program
  • printout radionuclides in a logical order
  • add default lung clearance classes to provide the maximum dose based on each element
  • allow entry of radionuclide input in either upper or lower case characters
  • eliminate a discontinuity in the leakage function
  • add an option to allow the user to enter a respirable fraction for inhalation dose calculations
  • add an option to allow the user to enter an occupancy factor for ground surface dose calculations
  • incorporate editorial changes in program output
  • enhance the method to estimate the building wake effect
  • evaluate the instantaneous release to a room
  • evaluate the resuspension of particulate activity
  • enhance the method for evaluation of dry deposition
  • perform calculation of an effective σ y and σ z when χ/Q is directly input.

RSAC-7 is the latest version of RSAC. The purpose of the RSAC 7 project was to upgrade the existing RSAC 6.2 software to include the new dose conversion factors (DCF). In addition to the new DCFs, the user community had suggested multiple changes to the software on both the input and output modules. The change requests are listed in Appendix A of the RSAC manual (INL/EXT-09-15275). RSAC-7.2 is the current release of RSAC-7 and it was released in 2010.

This revision of RSAC:

  • added internal dose conversion factors from ICRP 68 and 72
  • added risk analysis using the process of Federal Guidance Report 13.
  • added acute dose conversion factors for a 24 hour exposure from a sabotage event.
  • Corrected minor errors in the printing and display features
  • Added the capability to perform joint frequency meteorological conditions to calculate both 50% and 95% metrological conditions for input into RSAC.
  • Established an internal validation process to assure proper verification of installation parameters.
  • Established 20 new examples for execution of the enhanced capabilities of RSAC-7
  • Inputed units of Curies, grams and Becquerel are available in the direct input model.

RSAC 7 was developed by modifying RSAC 6.2; however, as a result of major modifications to the program, RSAC-7 is considered a new software project and not a maintenance upgrade of RSAC-6.2. The purpose of this project was to create RSAC-7 with sufficient quality so that it could confidently be released on an international scale to NQA-1-2000, “Quality Assurance Requirements for Nuclear Facility Applications,” Subpart 2.7, “Quality Assurance Requirements for Computer Software for Nuclear Facility Applications.”  In addition to the requirements of NQA-1-2000, NQA-1-2008 “Quality Assurance Requirements for Nuclear Facility Applications,” Subpart 2.7, “Quality Assurance Requirements for Computer Software for Nuclear Facility Applications,”  was also used as a basis for establishment of software requirements. Where a difference existed between the documents, the most conservative process or method was selected.

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