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The analysis of cylindrical sources,
which through user-specified input can be modeled to represent
miniature sources, line sources, disc sources, ring and thin-crescent
sources (through the combination of disk sources and penetrations
with plugs), cylindrical shells (through the combination of
large cylindrical sources), semi-infinite media (at any density),
and infinite media
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Built-in specifications for 216
pipes (ranging from 1/4"Sch10S to 36"Sch40), for
automatic source radius and wall thickness definitions
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Optimized, built-in source-meshing
algorithms for carefree applications
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Multiple cylindrical containers
with user-specified side-wall and end-wall thicknesses symmetrically
positioned around the source (user input may reduce each container
to a lateral sleeve, or to disks on both ends of the source)
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Multiple shield slabs positioned
either parallel or at right angles to the source axis
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Receptors positioned anywhere
inside the source, or at any source surface
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Receptors positioned on end [external
to the source and at distances from the source axis less than
the source radius], at locations external to all shield slabs
and/or containers
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Receptors positioned on side [external
to the source and at radial distances from the axis greater
than the source radius and at any elevation with respect to
the source], at locations external to all shield slabs and/or
containers
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Plugged penetrations for receptors
on end, with the penetration material in each container and
shield slab being user specified (receptor locations are limited
to positions along the penetration axis)
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Choice of 26 materials for the
source, containers, shield slabs and receptor medium, with
default (built-in) or user-specified densities
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Material-sequence-dependent buildup
factor formulation
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User-specified time-dependent
gamma spectra (with energies in the range 0.010 to 15 MeV),
or internally calculated 18-group spectra based on user-specified
radionuclide inventories [101-nuclide data base, with internally
defined inventories for daughter products in secular equilibrium
with their parents (for cases where the parent inventory is
user specified and that of the daughter product is not), though
without decay correction]
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Computation of time-dependent
dose rates to air (in rad/hr), and time-integrated interval
and cumulative doses (rad), for the following:
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A single source and multiple
receptors, or |
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Multiple sources and one
(and the same) receptor, the contribution from any given
source being either additive or subtractive, at user
specification
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A typical geometric arrangement
acceptable by the software is shown in Fig.
E.1. The user need only provide the following:
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General information regarding
the handling of the source (single or multiple source
geometries), any source intensity adjustment, and orientation
of the shield slabs |
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The source dimensions, material
and density for each container and each slab, the container
dimensions, materials and densities, along with the
material and density of the plug for any penetration
that may traverse the container |
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The receptor medium (material
and density) |
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The receptor location(s)
of interest, and the diameter of any associated penetration
that may affect any of the each receptors, and |
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Either the time-dependent
gamma spectra or a radionuclide inventory
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Typical applications of the software
include the following:
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Radiation levels from radioactive
recirculating fluids under Loss-of-Coolant-Accident
(LOCA) conditions (for the determination of vital-area
accessibilities and required shielding, and component
radiation damage) |
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Radiation monitor response
determinations (as required for the correlation of monitor
readings with emergency action levels) |
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Design of monitor/chamber
geometries for sampling gaseous radioactive effluents
under normal and accident conditions |
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Spent-fuel pool radiation
levels (for the determination of water depth requirements,
and potential radiation damage to immersed components) |
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Evaluation of shipping-cask
external radiation levels (spent fuel or other) |
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Shielding calculations related
to on-site storage of low-level and high-level waste |
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Evaluation of radiation
levels from waste disposal tanks, etc.
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FORTRAN 77; 4600 coded lines;
DOS and UNIX applications; ASCII file input; 132-column output
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The validity of DIDOS-5E has been
verified through extensive testing and through comparative
analysis with information available in the literature. In
general, dose rates were found to be within a few percent
of expected values, including receptors embedded in infinite
media of any density, where the energy-conservation principle
applies (energy absorbed = energy produced). |
