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ELISA-2
A software package developed for the radiological Evaluation
of LIcensing and Severe
Accidents at light-water nuclear
power plants. It is also suitable for selected routine applications,
such as buildup of radioactivity in purification systems, noble-gas
buildup in delay beds, atmospheric releases, etc.
Key Features
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444 radionuclides classifiable
into a maximum of 12 groups |
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Up to 3-member decay chains and
second parents |
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Core plus 3 compartments and offsite
locations |
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Two-compartment spray model with
user-specified DFs |
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Air recirculation and exhaust
filters |
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Dose rates and time-integrated
doses to air, skin and 8 organs |
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Indoor and outdoor finite-cloud
corrections |
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Gamma spectra wherever radioactivity
accumulates and in the released radioactive cloud |
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Ground contamination |
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etc. |
Basic Features at a Glance
- Applications:
- Routine applications, such as (a) activity buildup in
the RCS and associated components during normal operation
(based on user-specified core inventory and applicable escape
rate coefficients), (b) in-containment buildup of airborne
radioactivity from RCS leakage during normal operation,
and (c) atmospheric releases and ensuing air submersion,
inhalation and ground-shine radiation doses.
- Classical accidental releases (predefined source inventory
and instantaneous releases from the source/core at the time
of the accident).
- Alternative-Source-Term (AST) accidental releases (gradual,
time-phased releases from the source, in line with NRC Regulatory
Guide 1.183).
- 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) AST time intervals with no radioactive releases
from the source, and (c) selected routine releases and pre-accident
constant-feed scenarios.
- Fixed geometries for source plus one, two or three serially
connected compartments and outdoor receptors [for Exclusion
Area Boundary (EAB), Low Population Zone (LPZ), and Main Control
Room (MCR) habitability analyses].
- One-, two- and three-member decay chains, and second parents;
optional single-member decay chains for all radionuclides, 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).
- 444 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 group.
- Source inventory in Ci or Bq (or release rates from the source,
in ?Ci/sec or Bq/sec); doses in rad/rem or Gy/Sv.
- Built-in ORIGEN-2 optional 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,
currently affecting 74 radionuclides (83 decay chains counting
second parents) in the data library (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 releases 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, recirculation
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 submersion, ground contamination; air
gamma, air beta, skin, 7 organs, Total Effective Dose Equivalent
(TEDE), 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 TEDE; partial occupancy adjustments
for Control Room Habitability analyses].
- Time-dependent and time-integrated photon spectra wherever
radioactivity accumulates and in the released radioactive cloud
(ORIGEN-2 18-group and user-specified spectral structures; user-specified
element grouping, and all groups combined); preparation of output
files with spectral information for input into shielding codes.
(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 submersion exposures [compartments
(with subcompartments) 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); Federal Guidance Reports 11 and
12 (EPA 520/1-88-020 and EPA 402-R-93-081) dose conversion factors
(DCFs); TID-14844 DCFs for thyroid dose due to iodine inhalation;
RG 1.109 DCFs for whole body doses due to submersion in noble-gas
clouds, with equivalent DCFs prepared for the iodines; ELISA-2-generated
tabulation of the data library with identification of missing
information.
- FORTRAN 77; approximately 11.5 thousand coded lines (for Version
2.5); 7197-line data library; DOS and UNIX applications; ASCII
file free-format input; 132-column primary output file, with
detailed tabular presentations at user specified times (nuclide-specific
and group-element subtotals), and summaries; secondary output
files with photon spectra (user-specified element groupings
and all groups combined), and tabulation of time-dependent radioactivity
at all places of accumulation for a user-specified nuclide grouping
(for instance, noble gases, halogens and alkalis only).
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
Alernative-Source-Term Methodologies":
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P100-R22-A - User's Manual |
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P100-R22-B - Technical Manual |
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P100-R22-C - Programmer's Guide
and Source Listing |
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P100-R22-D - Data Library |
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P100-R22-E - Validation Test
Runs |
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P100-R22-F - Software Validation
Report |
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P100-R22-G-J - Software Upgrades
Since Original Issue in 1999 |
Further details are presented in the figures.
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