5.1.7. OPUS Module

The analysis of ORIGEN results often involves evaluating large amounts of output data that may include time-dependent nuclide and element inventories, radiological decay properties, and neutron, alpha, beta and photon source spectra. Visualization of the output data from ORIGEN often provides a means of rapidly evaluating the dominant nuclides in a problem, identifying important trends in the results, and providing insight into the problem that is not easily obtained otherwise. The OPUS utility program has been developed to read and process ORIGEN binary concentration results file (f71) into a format easily entered into graphics-plotting packages.

5.1.7.1. Key Features

The output of OPUS is a PLT file with extension “.plt” which can be easily read by most graphics packages, including the SCALE GUI Fulcrum. An example of the PLT file is shown in Figure 5.1.28.

Figure 5.1.28. Example of the OPUS PLT file.

The various types of data that can be returned by OPUS fall into two separate classes, briefly described as (1) dominant or selected isotopes or elements and (2) photon, alpha, beta and neutron source spectra. These requested data may be extracted for either irradiation or decay time periods of interest. One key feature of the program is that by default, it will automatically extract the 40 most dominant nuclides or elements in the problem, rank them using the output response and time periods of interest as specified by the user, and give the total response. The returned data may be selected, ranked, and plotted according to the group (types) of nuclides in the problem. The groups include the actinides, fission products, activation products, fission products and actinides, or all nuclides in the problem. The totals are printed for all nuclides in the specified group, and a subtotal is generated for all nuclides in the printed list. The user may also specify any other nuclide or element to be included in the output, regardless of its importance to the problem. The nuclides may be ranked using different output units of mass, density, atomic density, activity, toxicity, decay heat, or isotopic fractions.

Default values are assigned to most input variables, allowing a comprehensive visual analysis of returned data with relatively little user input.

5.1.7.2. Input Description

OPUS input records are limited to a maximum of 80 columns. A single data entry may be entered anywhere in a record but cannot be divided between two records; however, array-data entries may be divided over many records. A data entry (from left to right) is composed of a keyword, an equal sign (=), and numeric or alphanumeric data. A data entry is illustrated in the following example:

title="PWR 33 GWD/MTU 3.3 wt % U-235"

The program identifies keywords either by using only the first four characters in the keyword name or the full keyword name. In the example above, “titl” may be used, omitting the “e.” 1 Alphanumeric data (as titles or axis labels) must be enclosed in double quotes, with nuclide or element symbols being the notable exception.

1

Unlike in the previous OPUS versions, it is not permitted to enter four characters followed by any alphanumeric characters: only full keyword names or four-letter short-hands are allowed.

Floating-point data may be entered in various forms; for example, the value 12340.0 may be entered as 12340, 12340.0, 1.234+4, 1.234E+4, 1.234E4, or 1.234E04. Also, the value 0.012 may be entered as 12E-3, 12-3, 1.2-2, etc. Numeric data must be followed immediately by one or more blanks.

Array data (alphanumeric floating-point and integer) for an array-type parameter must always be terminated with an END that does not begin in column one.

Input parameters in a single OPUS sequence input (i.e., between “=opus” and “end”) may be entered in any order. Usually each sequence input produces a single plot file with the name “${OUTBASENAME}N.plt” where ${OUTBASENAME} is the base of the input file name, e.g., my.inp has the base name “my,” and “N” is an 18-digit integer that is incremented with each opus plot.

The OPUS input uses keywords. Keywords, descriptions, and allowed choices for each entry are listed in Table 5.1.14 for plot setup options and Table 5.1.15 for response units and nuclide selection. Input keywords and their choices occupy the first column. The next two columns indicate the type of plot in which the keyword may be entered. The last column is a description of the input keyword. All spectral data also supports a keyword between the short 4-character form and the long “spectrum” for with the suffix “spec”, e.g. “anspec” and “nspec”.

Table 5.1.14 OPUS input for plot setup

Input keywords

Nuclide /

element plot

Spectra

plot

Keyword description

LIBRARY= (“”)

*

*

ORIGEN binary cross section library (.f33). Only required in order to perform reaction rate calculations (see ABSO and FISS units below).

DATA= (“ft71f001”)

*

*

ORIGEN concentrations file (.f71). If enetered, must be enclosed in double quotes.

TITLE= (“”)

*

*

Title of plot. If entered, must be enclosed in double quotes.

TYPARAMS=

NUCLIDES

ELEMENTS

 

*

*

 

NA

NA

Inventory data to be plotted

individual nuclides (DEFAULT)

elements

TYPARAMS=

ASPECTRUM

BSPECTRUM

GSPECTRUM

NSPECTRUM

SFSPECTRUM

ANSPECTRUM

DNSPECTRUM

 

NA

NA

NA

NA

NA

NA

NA

 

*

*

*

*

*

*

*

Spectral data to be plotted

alpha spectrum

beta spectrum

photon spectrum

total neutron spectrum from all sources

spontaneous fission

\(\left(\alpha,n\right)\)

delayed neutrons

FACTOR=

*

NA

User-defined multiplicative factor for all concentrations

VOLUME=

*

NA

Material volume in cm 3; required when plotting in units of grams/cm 3 or atoms/barn-cm

XLABEL=

YLABEL=

*

*

X- and Y-axis labels. If this parameters is not entered, a label is generated automatically. If entered, it must be enclosed in double quotes

COLS= (YES)/NO

Print nuclide edits by colummn (one nuclide per column)

ROWS= (YES)/NO

Print nuclide edits by colummn (one nuclide per row)

TIME=

SECONDS

MINUTES

HOURS

DAYS

YEARS

*

*

*

*

*

*

NA

NA

NA

NA

NA

NA

Unit of time to be plotted

seconds

minutes

hours

days (DEFAULT)

years
Table 5.1.15 OPUS input for response units and nuclide selection

Input keywords

Nuclide /

element plot

Spectra

plot

Keyword description

NRANK=(40)

*

N/A

Total number of nuclides or elements to be returned for the plot. If user-selected nuclides or elements are requested (see SYMNUC), output will include these nuclides plus any remaining ones with the highest rankings for the quantity specified. The total and subtotal are always printed.

Default is not used if SYMNUC is entered.

UNITS=

(GATO)

(INTENSITY)

*

N/A

Requested data units

Gram-atoms are default for nuclide / element plots, and particles / MeV-sec are default for spectrum plots

ABSORPTIONS

*

N/A

Absorption / removal rate (using removal XS on library)

AIRM**3

*

N/A

Radiotoxicity; cubic meters of air to dilute to RCGa

APELEM

*

N/A

Atom % of element; isotopic atom percentages of all elements specified in SYMNUC

ATOMS / B-CM

*

N/A

Atoms/barn-cm; requires VOLUME entry

BECQUERELS

*

N/A

Radioactivity, Bq.

CAPTURES

*

N/A

Capture reaction rate (removal minus fission; not equivalent to radiative capture)

CURIES

*

N/A

Radioactivity, Ci

FISSIONS

*

N/A

Fission reaction rate (using XS on library).

GAMWATTS

*

N/A

Gamma-ray thermal power, watts

GATOMS

*

N/A

Gram atoms, gram-atomic weights or moles

GPERCM**3

*

N/A

Partial density, grams/cm3; requires VOLUME entry

GRAMS

*

N/A

Mass, grams

H2OM**3

*

N/A

Radiotoxicity; cubic meters of water to required to dilute to to RCGw

KILOGRAMS

*

N/A

Mass, kilograms

WPELEM

*

N/A

Weight % of element; isotopic weight percentages of all elements specified in SYMNUC

WATTS

*

N/A

Total thermal power, watts

PARTICLES

N/A

*

Print spectra in units of particles/sec

INTENNSITY

N/A

*

Print spectra in units of particles/MeV-sec (normalized to energy bin width)

ENERGY

N/A

*

Print spectra in units of MeV/MeV-s (normalized to energy bin width; multiplied by mean bin energy)

LIBTYPE=

LITE

ACT

FISS

FISSACT

ALL

*

*

*

*

*

*

N/A

N/A

N/A

N/A

N/A

N/A

Selects sublibrary(ies) for nuclide/elements

Include light-nuclide sublibrary

Include actinide sublibrary

Include fission product sublibrary

Include actinide and fission products

Include all (DEFAULT)

SYMNUC=

*

N/A

Symbolic notation of nuclides or elements requested in the plot data. The list is an array terminated with an END.

Nuclide entry is by chemical symbol and mass number, separated by a dash “–”. Metastable states are indicated with an “m” immediately following the mass number (e.g., 242mAm). Element entry is by chemical symbol only (e.g., Pu)

For nuclide entry, it is also allowed to use element identifiers; in such cases, all isotopes of the element found in the ORIGEN library are used.

SORT=

*

N/A

Option to sort user-requested nuclides input via the SYMNUC array by descending order of importance. If SORT is not given or is SORT=NO, the order of the nuclides in the plot table is the same order as in the input.

Options that can be given to SORT are the same as for UNITS. If SORT=YES, the same units provided in the UNITS entry are used.

RESPONSE=

*

N/A

Optional, user-specified arbitrary response conversion factor array. These factors are applied to the individual nuclides after conversion to quantities in the units requested by UNITS.

Entries are in nuclide ID-response factor pairs. Nuclide identifiers are entered as legacy ORIGEN ZZAAAI 6-digit integer IDs, where the isomeric state is the last digit.

The array must be terminated with an END.

The default values are given in parentheses after the input keyword definitions. Only the first four characters of any keyword (the letters are in bold) plus the “=,” are required; they can be used instead of the full keyword name. However, unlike in previous versions of OPUS, the only two options accepted are the full keyword name or its first four letters. The keyword default value is listed in parentheses, and values are provided for almost all numeric input and axis labels. For example, the user has the option to enter axis labels using XLABEL= and YLABEL= entries, or “built-in” axis labels based on the time units and the type of data units can be used.

The remaining sections give more detail on the nuclide/element plots, the spectra plots, and time range, and case selection to further filter the results on an f71 file.

5.1.7.2.1. Nuclide/element plots

Various responses may be returned either by nuclide or by element, as a function of time, for a specified time interval. By default, the top nuclides/elements contributing to the response of interest over the time range are returned. An explicit list of nuclides/elements can also be entered, in which case these nuclides will always be included, regardless of their ranking. Results for nuclides in specific sublibraries may be filtered (e.g., to only see output of 155Gd the fission product (FP) sublib and not the light nuclide version [LT] sublib. The default behavior is to sum over all sublibs.

Response totals are always generated for each plot. These totals represent the sum over all nuclides or elements in the specified library type. In addition, a subtotal is printed (both in the printout and the plot file) that represents the sum over the printed nuclides or elements. The subtotal can be very useful in identifying whether the nuclides in the printed list include all of the dominant nuclides in the problem.

OPUS allows the user to sort using any of the provided concentration units. For each nuclide/element, approximate integral value over all selected time steps is calculated in the selected units; nuclides/elements are then ranked according to this value. The NRANK cutoff is applied after the sort has been performed.

It is permitted to enter SORT=YES, which is equivalent to setting SORT= to the same value as UNITS=.

If the SORT key is not entered, nuclides/elements are sorted according to their position in the SYMNUC array.

5.1.7.2.2. Spectra plots

Alpha, beta, photon and neutron energy spectra calculated by ORIGEN may also be stored on the f71 file, and plotted by OPUS. One difference in the units of the spectra returned by OPUS and those printed by ORIGEN is that the intensities are typically converted from units of photons/s (stored on f71 file) to particles/s-MeV by dividing by the energy-group width. This conversion produces intensities that are more easily comparable across different energy groups and energy-group structures. Energy-intensity spectra in units of MeV/s-MeV and intensity spectra in units of particles/s may also be requested.

5.1.7.2.3. Selection of plotting data

OPUS provides four basic options for selecting a subset of the data on an f71 file:

  1. a range of times with TMIN and TMAX (floating point numbers),

  2. a range of positions on the f71 file with MINPOSITION and MAXPOSITION (integers),

  3. a single CASE selection, and

  4. a list of positions in the NPOSITION list.

A full overview of keywords that can be entered for time point selection is given in Table 5.1.16.

If no selection inputs are used, all available steps on the concentration file are printed. Range bounds (CASE, TMIN, TMAX, MINPOSITION, MAXPOSITION) are used as independent constraints, so any combination of those can be supplied, in which case all of the specified constraints are applied.

In case invalid positions are specified in the NPOSITION array, an error is raised, and no valid output is produced; the same happens if no steps fit into the specified selection.

The case number is useful for ORIGEN stacked cases. Furthermore, TRITON stores the mixture number (with 0 for the sum of all depletion materials and -1 for the sum of selected materials) as the case number, so this option can be used to obtain a plot of the desired depletion mixture without actually knowing the time step numbers=. When an ORIGEN f71 file is accessed, a table of contents is printed in the output (.out) file. This can be very useful for understanding what is contained on the f71 at each position.

Table 5.1.16 OPUS input keywords for data set selection

Input keywords

Type

Keyword description

NPOSITION=

Array

List of all requested position numbers of data (on NUMUNIT), in ascending order. No other entries are required since NPOSITION is a unique data set identifier. Terminate with END.

NPOSITIONS cannot be specified together with any of TMIN, TMAX, MINPOSITION or MAXPOSITION.

If none of the position selectors is entered, all available positions on the data file will be returned.

CASE=

Variable

Number of ORIGEN case (or, a mixture number for TRITON-produced f71 files).

MINPOSITION=

Variable

Minimum position number, used to request a range of positions

MAXPOSITION=

Variable

Maximum position number

All positions between MINPOSITION and MAXPOSITION, inclusive, are requested.

MINPOSITION and/or MAXPOSITION cannot be specified together with NPOSITIONS, but they can be specified at the same time as TMIN and/or TMAX. Up to all four conditions (TMIN, TMAX, MINPOSITION, MAXPOSITION) will be used to constraint the selected time points.

If none of the position selectors is entered, all available positions on the data file will be returned.

TMAX=

TMIN=

Variable

Variable

Minimum and maximum time for selection of positions on the data file. The units of TMAX and TMIN are the same as for TIME.

TMIN and/or TMAX cannot be specified together with NPOSITIONS, but they can be specified at the same time as MINPOSITION and/or MAXPOSITION. Up to all four conditions (TMIN, TMAX, MINPOSITION, MAXPOSITION) will be used to constraint the selected time points.

If none of the position selectors is entered, all available positions on the data file will be returned.

5.1.7.3. Plot File Formats

The plot file produced by OPUS is a text file that contains plot information, including the title, axis labels, plot type, and the time-dependent data for inventory-type plots or energy-dependent data for spectral-type plots. The plot file is a free-format reading, so the column positions have no particular significance. However, the plot files created by OPUS are aligned by column to facilitate reading of the files by other graphics programs.

File header information

The format of the first five records of the plot file is common to all plot types. They are:

Record 1: TITL - problem title (maximum 32 characters)

Record 2: XHEA - x-axis label (maximum 20 characters)

Record 3: YHEA. y-axis label (maximum 20 characters)

Record 4: Plot type - The type of plot is selected by the words “nuclide,” “element,” “case,” or “spec.” The nuclide and element entries have the same effect and produce time-dependent plots of individual nuclides or elements in the specified units. The “case” entry is used to identify case comparisons of total quantities or individual nuclides. The “spec” entry identifies spectral-type plots.

The remaining records and formats depend on the plot type specified in Record 4.

Nuclide and element plot types

Record 5: NPTONC, KTOT - the number of time points (x-axis) for the plot data KTOT - the number of nuclides or elements in the plot; includes the last record that contains the totals, if present

Record 6: TIMES(NPTONC) - NPTONC entries for the times associated with each data point; units are in the units specified in Record 2 (XHEA)

Record 7: SYMBOL, (X(N,I), I=1, NPTONC) - symbol is the alphanumeric symbol for the nuclide or element. No spaces are permitted in PlotOPUS. This symbol entry is followed by NPTONC entries containing the plot data for the nuclide or element SYMBOL with index N.

Record 8: Record 7 is repeated for all KTOT nuclides or elements.

Record 7+KTOT: Last record - contains the totals or other related quantity for the plot. The record has the same format as Record 7.

Spectral plot types

Record 5: NPTONC, NGP - the number of entries that follow to construct the spectral histogram, where NGP=(NG+1)*2 and NG is the number of energy groups. The histogram is made using a series of connecting lines, and therefore does not require any special histogram plotting capability in the graphics code.

Record 6: EN, YY - Each record contains a pair of entries: EN is the energy (MeV), and YY is the value for energy EN.

Repeat Record 6 NGP times.

Case comparison plot types

Record 5: NCAS - the negative value of the total number of cases in the plot

Record 6: NPTONC - the number of time points (x-axis) for the plot data for the case (non-user-entered data)

Record 7: INPOIN the number of time points (x-axis) for the plot data for user-entered data

Record 8: XINP(INPOIN) - INPOIN entries for the times associated with each data point of the user-entered data

Record 9: YINP(INPOIN) - INPOIN entries containing the plot data for the user-entered data

Record 10: LEGEND - legend for the user-entered data case.

The remaining records contain the case comparison data for the non-user-input data. Repeat records 7, 8, 9, and 10 for the case comparison plots, NPTONC times (same as case comparisons with no user-entered data).