ELISA-2

A software package developed for the radiological Evaluation of LIcensing and Severe Accidents at light-water nuclear power plants. It is based on the classical and alternative-source-term methodologies.

Key Features

	414 radionuclides classifiable into a maximum of 12 groups
	Up to 3-member decay chains and second parents
	Core plus 3 compartments and offsite locations
	Two-compartment spray model with user-specified DFs
	Air recirculation and exhaust filters
	Dose rates and time-integrated doses to air, skin and 8 organs
	Indoor and outdoor finite-cloud corrections
	Gamma spectra wherever radioactivity accumulates and in the released radioactive cloud
	Ground contamination
	etc.

 

Basic Features at a Glance

Release types: Classical accidental releases (instantaneous releases from the source/core at the time of the accident)Revised-Source-Term (RST, NUREG-1465, Ref. 1) accidental releases (gradual, time-phased releases from the source) Routine releases (air immersion, inhalation and ground-shine pathways only) Pre-accident constant-feed conditions (time-interval dependent), followed by accidental releases (such as gaseous-tank fill ups prior to rupture, and establishment of reactor coolant equilibrium conditions prior to a line break and iodine spiking) Hybrid (exact/numerical) solution for optimized execution, with exact solutions being utilized for (a) all classical accidental releases, (b) RST time intervals with no radioactive releases from the source, and (c) selected routine releases and pre-accident constant-feed scenarios

	Source plus one, two or three serially connected compartments and outdoor receptors [for Exclusion Area Boundary (EAB), Low Population Zone (LPZ), and Control Room (CR) habitability analyses]
	One-, two- and three-member decay chains, and second parents; optional single-member decay chains, for testing and assessment purposes; materially-balanced equations without black-hole sinks (such that, for instance, halogen decay in the core and in any other place of accumulation, leads to the production of airborne noble gases)
	414 radionuclides; up to 12 user-specified element groups; instantaneous or multi-phase releases from the source, with pre-release buildup and decay; three chemical forms for each element ground

	Source inventory in Ci or Bq (or release rates in µCi/sec, Bq/sec); doses in rad/rem or Gy/Sv
	Built-in ORIGEN-2 default inventories for two PWRs and two BWRs (in Ci/MWt, for standard and extended burnups)
	Optional inclusion in the user-specified inventory of the radioactivity of undefined daughter products in secular equilibrium with their parents, based on default or user-specified conditions (e.g., Ba137m and its precursor Cs137)
	One- and two-compartment spray models, optionally with user-specified DFs for automatic spray-effectiveness termination; time-dependent spray removal constants for each element group and each species; time-phased release from the source, split between the sprayed and unsprayed regions according to user specification; time-dependent air circulation flow between sprayed and unsprayed regions
	Pre-accident source inventory decay (as needed for fuel handling accidents, for instance)
	Time-dependent compartment filtration flows; intake and exhaust filter time-dependent bypass fractions; filter removal efficiencies for each element group and each species
	Time-dependent radioactivity levels at all places of accumulation, including ground contamination
	Time-dependent release rates, interval releases and cumulative releases to the atmosphere; released cloud concentrations
	In-transit buildup and decay for offsite receptors
	Time-dependent radiation dose rates, interval doses and cumulative doses [nuclide-specific, group-element specific and overall totals; inhalation, air immersion, ground contamination; air gamma, air beta, skin, 7 organs, Effective Dose Equivalent (EDE), classical TID-14844 thyroid for iodines, Regulatory Guide 1.109 whole body; percent contributions of betas to skin dose; percent contribution of inhalation pathway to total doses to the lung, thyroid and EDE; partial occupancy adjustments for CR personnel]
	Time-dependent and time-integrated gamma spectra wherever radioactivity accumulates and in the released radioactive cloud (ORIGEN-2 18-group and user-specified reduced spectra; user-specified element groups, and all groups combined); preparation of output files with spectral information for input into shielding codes, such as ENTECH's DIDOS-5E. (Examples of spectral files and uses: RCS liquids and EQ/accessibility applications; filter radioactivity and CR habitability/filter heat-up rates; containment airborne radioactivity and direct-shine doses/process-monitor readings; overhead cloud radioactivity and CR doses)
	Finite-cloud adjustments for air immersion exposures (compartments and offsite receptors, the latter requiring as input special finite-cloud-corrected atmospheric dispersion factors, as computed by ENTECH's AEOLUS-3 software)
	Data library based on ORIGEN-2 (decay constants, branching fractions, photon spectra) and Federal Guidance Reports 11 and 12 (EPA 520/1-88-020 and EPA 402-R-93-081, dose conversion factors); software-prepared tabulation of the data library with identification of missing information
	FORTRAN 77; 9800 coded lines, approximately; 6683-line data library; DOS and UNIX applications; ASCII file input; 132-column output, with detailed tabular presentations at user specified times, and summaries (with and without partial occupancy for control-room applications)

Documentation Package

P100-R22, "A Software Package for the Radiological Evaluation of Licensing and Severe Accidents at Light-Water Nuclear Power Plants Based on the Classical and Revised-Source-Term (RST) Methodologies":

	P100-R22-A - User's Manual
	P100-R22-B - Technical Manual
	P100-R22-C - Programmer's Guide and Source Listing
	P100-R22-D - Data Library
	P100-R22-E - Validation Test Runs
	P100-R22-F - Software Validation Report

Further details are presented in the figures.