2.5. Input and Output Files

2.5.1. SAS Input File

In the past, SAS4A/SASSYS-1 input was limited to 80-column, fixed-formatted card images. This is still the basic format used by most SAS input files. However, Version 5.3 introduces the option to use free-formatted input of any length for integer and floating-point input blocks. A full description of the contents of the input file is contained in Section 2.7.

In all SAS input files, the first three (non-comment) records of the input file are required. The first two records each contain 72 columns of problem title data that will appear at the top of each page of the output file. Columns 73‑80 of the first card image must contain, left adjusted, the major and minor version number of the SAS code being executed. The third record is the storage allocation card, which provides SAS information needed to allocate the various data containers used for input processing. If the DIF3D interface option is invoked, an additional storage allocation card (fourth record) is required.

If the current execution is to be restarted from a prior execution, the input file must contain a RESTART directive to invoke the reading of a restart file from RESTART.bin (see Section 2.5.3). The reading of the restart file takes place at the point the restart record is encountered on the input file. Input blocks loaded before the restart record will be over-written by the restart file data, and input blocks following the restart record will modify or replace data read from the restart file.

The input data blocks for SAS are described in Section 2.7. Each input data block begins with a block identifier record and ends with a block delimiter record. The block identifier record contains the block name and number, and two integers denoting the relevant current channel and the type of background data fill to be supplied before data reading begins. (The background may be “zeros” or the same block entered previously for this or another channel.) The block delimiter record accepts either a negative integer one (“-1” right adjusted) entered in the first I6 field of the record, or a left adjusted “END” statement.

Within the body of a SAS input file, INCLUDE directives may be used to read additional input data from external files. Any number of nested INCLUDE directives may be used, but circular references are not allowed. Support for INCLUDE directives was added in Version 5.3.

Reading of input is terminated by an ENDJOB directive. Any records following the ENDJOB record are ignored.

2.5.2. SAS Output Files

SAS4A/SASSYS-1 prints ascii output as 133-column, formatted, printed line images. Listings of example output files can be found in the example problems output listings provided with the code distribution.

The ascii output file is occasionally divided by logical page breaks. (A fixed page size of 60 lines is no longer maintained.) Each logical page break is headed with the two title records that begin the input deck. The title lines also contain code version identification, the page number, job and user identification, the execution date, and the clock time. Pages containing channel-dependent information will have the channel number printed in the upper left-hand corner.

The ascii output file begins with a print of information from the header, including primary and secondary titles and memory allocation flags. During input processing, each record from the input file is recorded to the file SAS.log. An optional compiled version of the input may be written to INPUT.dat (see IPDECK). An optional, formatted and annotated print of the input data is available, followed by a tabular print of coolant material properties. This is followed by printer plots of curves formed by the tabular fitting procedure.

The steady-state results are printed next, beginning with prints of channel-dependent data. The prints vary depending on the computational modules invoked, but usually contain node-wise masses, porosities, and temperatures, as well as radial and axial pin geometry. Also printed are nodal powers and reactivity feedback coefficients. Following the channel-dependent prints, steady-state results from the primary loop (PRIMAR‑4), control system, and balance-of-plant may appear, if those modules are employed.

A short print of time, power, and reactivity is produced on each main transient time step. The exact form of this print varies depending on whether the default reactivity feedback routines are employed or the EBR-II feedback routines are used. On specified main time steps, long prints of the current channel conditions (geometry, pressure, temperature, etc.) are produced. In addition, each module may produce intermittent transient prints of calculated results. These prints are controlled by input data. Extensive diagnostic prints may also be triggered through input for most of the computational modules.

SAS4A/SASSYS-1 also prints binary output files. These files and their contents are summarized in the following sections.

2.5.2.1. CHANNEL.dat

CHANNEL.dat is output if requested by the user (ICLCMP). At a user-defined frequency, see MSTPL1, channel-dependent and core wide data is written to the CHANNEL.dat file. The CHANNEL.dat file is an unstructured binary file. Converter utilities are provided as part of the distribution package. The converter utilities translate the binary data into a CSV or XML format.

Each time data is written to the binary file a row is created for each channel that contains the data presented in Table 2.5.1. Following the channel-dependent entries is an additional row containing the core-wide data, presented in Table 2.5.2, is written.

Data that has a corresponding CSV column number is converted by the CHANNELtoCSV tool distributed with the code.

Table 2.5.1 Channel-Dependent Contents of CHANNEL.dat

Binary Index	CSV Column	Data Type	Description
1		Integer	Time step number
2	Appears in CSV file name	Integer	Channel number
3		Integer	KMAX
4	2	Double	ZFuel - Fuel elevation at JCLN or Peak (m)
5	3	Double	ZClad - Clad elevation at JNEN or Peak (m)
6	4	Double	ZCool - Coolant elevation at JNCN or Peak (m)
7	5	Double	ZStruct - Structure elevation at JNSN, if specified (m)
8	6	Double	Fuel elevation at JRPRO, if specified (m)
9	7	Double	Average coolant temperature at ZCool (K or C)
10	8	Double	Clad temperature at ZClad (K or C)
11	9	Double	Fuel temperature at ZFuel (K or C)
12	10	Double	Coolant saturation temperature at ZCool (K or C)
13	11	Double	Fuel melt fraction (-)
14	12	Double	Clad midpoint temperature at ZClad (K or C)
15	13	Double	Clad melt? (No - 0.0, Yes - 1.0)
16	14	Double	Coolant temperature at ZCool (K or C)
17	15	Double	Inner structure temperature at ZStruct (K or C)
18	16	Double	Channel outlet flowrate (kg/s per pin)
19	17	Double	Channel inlet flowrate (kg/s per pin)
20	18	Double	Channel outlet temperature (K or C)
21	19	Double	Channel inlet temperature (K or C)
22-25		Double(4)	Reserved
26		Integer	Reserved
27		Double	Reserved
28-29		Integer(2)	Reserved
Remaining		Double(3*KMAX)	Reserved

Table 2.5.2 Core-Wide Contents of CHANNEL.dat

Binary Index	CSV Column	Data Type	Description
1	1	Integer	Time step number (-)
2	2	Integer	Power option, IPOWER (-)
3	3	Double	Time (s). Note the CSV converter copies the time entry into column one of each channel specific file.
4	4	Double	Time step size (s)
5	5	Double	Normalized total power (-)
6	6	Double	Reactor period (s)
7	7	Double	Integrated normalized total power (-)
8	8	Double	Normalized decay power (-)
9	9	Double	Net reactivity ($)
10	10	Double	Programmed reactivity ($)
11	11	Double	Doppler reactivity ($)
12	12	Double	Axial expansion reactivity ($)
13	13	Double	Radial expansion reactivity ($)
14	14	Double	CRDL expansion reactivity ($)
15	15	Double	Coolant void reactivity ($)
16	16	Double	Fuel relocation reactivity ($)
17	17	Double	Clad relocation reactivity ($)
Remaining		Double(3* NCHAN + 1)	Reserved

2.5.2.2. PRIMAR4.dat

PRIMAR4.dat is output if requested by the user (NBINOT > 0). Data is written to PRIMAR4.dat at a frequency specified by the user (INULLT, IBINST). The PRIMAR4.dat file is an unstructured binary file. Converter utilities are provided as part of the distribution package. The converter utilities translate the binary data into a CSV or XML format and print the formatted data to the standard output.

Each time data is written to PRIMAR4.dat, a row is created that contains the values shown in Table 2.5.3. For non-restart cases, the first row in the PRIMAR4.dat file has the IBINOT information appended to the row. In this case, at binary index 5 + NCols NBINOT is written as an Integer. In columns (6 + NCols) - (5 + NCols + NBINOT) a transpose of the IBINOT information is written as an Integer. This information is not included in the binary file for restart cases and is therefore not utilized by the converter utility.

Table 2.5.3 Initial Contents of PRIMAR4.dat

Binary Index	CSV Column	Data Type	Description
1	1	Integer	Time step number
2	2	Integer	PRIMAR-4 time step number
3	3	Integer	NCols - Total number of output columns
4	4	Double	Time (s)
5 - (4 + NCols)	5 - (4 + NCols)	Double(NCols)	Output data requested in IBINOT

2.5.2.3. CONTROL.dat

CONTROL.dat is output when the control system is in use and the user requests the data is printed. Users can define the frequency of CONTROL.dat print using the J1 parameter for signal 999. The CONTROL.dat file is an unstructured binary file. Converter utilities are provided as part of the distribution package. The converter utilities translate the binary data into a CSV or XML format and print the formatted data to the standard output.

CONTROL.dat contains a header section which defines the number of signals contained within the file and a description of the signals. The format of the header section is described in Table 2.5.4. Each time data is written to CONTROL.dat, i, two rows are created that contain the values shown in Table 2.5.5.

Table 2.5.4 Initial Contents of CONTROL.dat

Binary Entry	Binary Index	Data Type	Description
1	1	Integer	NSigs - total number of signals
2	1 - (NSigs - 1)	Integer(NSigs)	Signal Number
3	1 - (NSigs - 1)	Integer(NSigs)	Signal Type Id
4	1 - (NSigs - 1)	Character(32*NSigs)	Signal Type Description

Table 2.5.5 Main Contents of CONTROL.dat

Binary Entry	Binary Index	CSV Column	Data Type	Description
i	1	1	Integer	PRIMAR-4 time step number (-)
i	2	2	Double	Time at the beginning of the time step (s)
i + 1	1 - (NSigs - 1)	3 - (2 + NSigs)	Double(NSigs)	Signal values

2.5.2.4. STRATCV.dat

STRATCV.dat is output when the stratified volume model is active and the user requests the data is printed. Users can define the frequency of STRATCV.dat print using the IFT16 parameter. The STRATCV.dat file is an unstructured binary file. Converter utilities are provided as part of the distribution package. The converter utilities translate the binary data into a CSV or XML format.

Each time data is written to STRATCV.dat, i, several rows are created that contain the values shown in Table 2.5.6 and Table 2.5.7. If users define a negative value for IFT16, additional debug information is included in the binary file, this information is presented in Table 2.5.8. Table 2.5.7, and Table 2.5.8 if debug information is requested, is written to the binary file for each stratified volume, j.

Table 2.5.6 Contents of STRATCV.dat

Binary Entry	Binary Index	CSV Column	Data Type	Description
i	1		Integer	Print frequency, IFT16 (-)
i	2		Integer	NSTRCV - Number of stratified CVs (-)
i	3	1	Integer	PRIMAR-4 time step number (-)
i	4	2	Double	Time (s)
i + 1			Multi-line entry for each CV	see Table 2.5.7

Table 2.5.7 Contents of STRATCV.dat for a given stratified volume

Binary Entry	Binary Index	CSV Column	Data Type	Description
j	1	Appears in CSV file name	Integer	ICVSTR - Stratified CV number
j	2	3	Integer	NL4 - Number of layers
j	3	4	Integer	ISTAG4 - Stage number
j + 1	1	5	Double	ZLAYR4(1) - Bottom elevation of first layer (m)
j + 1	2	6	Double	TSTCV4(1) - Temperature of first layer (K)
j + 1	3	7	Double	XLSTM4(1) - Mass of first layer (kg)
j + 2	1	8	Double	ZLAYR4(2) - Bottom elevation of the second layer (m)
j + 2	2	9	Double	TSTCV4(2) - Temperature of second layer (K)
j + 2	3	10	Double	XLSTM4(2) - Mass of second layer (kg)
j + 3	1	11	Double	ZLAYR4(3) - Bottom elevation of third layer (m)
j + 3	2	12	Double	TSTCV4(3) - Temperature of third layer (K)
j + 3	3	13	Double	XLSTM4(3) - Mass of third layer (kg)
j + 4	1	14	Double	ZLAYR4(1+NL4) - Upper elevation of the last layer (m)

Table 2.5.8 Optional debug contents of STRATCV.dat for a given stratified volume

Binary Entry	Binary Index	CSV Column	Data Type	Description
j + 5	1	15	Double	WPLUME - Flow rate into plume (kg/s)
j + 5	2	16	Double	TPLUME - Temperature of plume (K)
j + 5	3	17	Double	Z0 - Plume established height (m)
j + 5	4	18	Double	V0 - Plume exit velocity (m/s)
j + 5	5	19	Double	VJ - Plume velocity at interface (m/s)
j + 5	6	20	Double	FR - Froude number (-)
j + 5	7	21	Double	HJET - Jet height (m)
j + 5	8	22	Double	WENTR - Flow entrainment rate (kg/s)

2.5.2.5. MFUEL Binary Files

As described in Section 9.6, when the MFUEL model is activated, a pre-transient and a transient binary file are created which contain the peak values of relevant parameters at the end of a main MFUEL time step. Two unique binary files are created for each channel, one for the pre-transient results and one for the transient results. A converter utility is provided as part of the distribution package. The converter utility translates the binary data into a CSV.

The MFUEL Peak value file contains a header section which defines the channel number, axial and radial meshing, the number of data columns and the time unit. The format of the header section is described in Table 2.5.9. Each time data is written to a peak axial file, i, a row is created that contains the values shown in Table 2.5.10.

MFUEL also outputs a pre-transient binary file including axial distributions of relevant parameters. Users can control the frequency at which the axial data is written during pre-transient characterization using the table-based MSTEP input. A unique binary file is created for each channel that uses MFUEL. A converter utility is provided as part of the distribution package. The converter utility translates the binary data into a multiple CSV files.

The axial-dependent MFUEL file contains a header section which defines the channel number, the number of included time steps, the axial meshing, and the number of data columns. The format of the header section is described in Table 2.5.11. Each time data is written to the axial-dependent file, i, MZ rows are created that contain the values shown in Table 2.5.12.

Table 2.5.9 Initial Contents of the Peak Value MFUEL Files

Binary Entry	Binary Index	Data Type	Description
1	1	Integer	iChan - channel number
1	2	Integer	MZ - number of axial fuel nodes
1	3	Integer	NEP - number of radial nodes
1	4	Integer	nCol - number of data columns
1	5	Character(3)	Unit of time, sec - seconds, or day - days

Table 2.5.10 Contents of MFUEL Peak Channel Files

Binary Entry	Binary/CSV Index	Data Type	Description
i	1	Double	Time (days for steady state file, seconds for transient file)
i	2	Double	Maximum burnup (at%)
i	3	Double	Maximum linear heat rate (kW/m)
i	4	Double	Maximum fuel temperature (K)
i	5	Double	Maximum clad inner temperature (K)
i	6	Double	Maximum clad hoop stress (MPa)
i	7	Double	Maximum fuel permanent axial expansion (%)
i	8	Double	Maximum fuel total axial expansion (%)
i	9	Double	Maximum clad permanent axial expansion (%)
i	10	Double	Maximum clad total axial expansion (%)
i	11	Double	Maximum fission gas release (%)
i	12	Double	Maximum plenum pressure (MPa)
i	13	Double	Maximum total clad hoop strain (%)
i	14	Double	Maximum total creep hoop strain (%)
i	15	Double	Maximum thermal creep hoop strain (%)
i	16	Double	Maximum irradiation creep hoop strain (%)
i	17	Double	Maximum volumetric swelling (%)
i	18	Double	Maximum total clad wastage (microns)
i	19	Double	Maximum lanthanide wastage (microns)
i	20	Double	Maximum eutectic wastage (microns)
i	21	Double	Maximum Na corrosion thickness (microns)
i	22	Double	Maximum CDF (-)
i	23	Double	Maximum MCF (-)
i	24	Double	Maximum neutron fluence (n/cm 2)
i	25	Double	Maximum clad dose (dpa)

Table 2.5.11 Initial Contents of the MFUEL Axial Files

Binary Entry	Binary Index	Data Type	Description
1	1	Integer	iChan - channel number
1	2	Integer	nSteps - number of time steps included in the file
1	3	Integer	MZ - number of axial nodes
1	4	Integer	nCol - number of data columns

Table 2.5.12 Contents of MFUEL Axial Files

Binary Index	Data Type	Description
1	Double	Axial location (m)
2	Double	Relative axial location (-)
3	Double	Cold cladding strain (%)
4	Double	Clad inner wastage (microns)
5	Double	Clad inner temperature (C)
6	Double	Clad hoop stress (MPa)
7	Double	Fuel outer radius (m)

2.5.3. Auxiliary Input and Output Files

The input and output files used in SAS4A/SASSYS-1 are listed in Table 2.5.13.

Table 2.5.13 SAS4A/SASSYS-1 Assigned External Files

File	Type	Assigned Use	Subroutine
stdin	Formatted	Input Data Records	READIN
stdout	Formatted	Printed Output	READIN
			DATOUT
			SSPRNT
			TSPRNT
			PSHORT
			PKPAGE
INPUT.dat	Formatted	Edited Input Data Records	DATOUT
8	Formatted	Scratch BOP Input Data	READIN
			RENUM
SAS.log	Formatted	Printed Output
CHANNEL.dat	Binary	Main Time Step Plotting	TSPLOT
12	Binary	PLUTO2/LEVITATE Data for Plotting	PLOUT
13	Binary	PLUTO2/LEVITATE Data for Plotting	PLOUT
14	Binary	PLUTO2/LEVITATE Data for Plotting	PLOUT
PRIMAR4.dat	Binary	PRIMAR‑4 Data for Plotting	SSPRPL
			TSPRPL
CONTROL.dat	Binary	Control System Signal Data	CNTL_Data
16	Formatted	PINACLE/LEVITATE Data for Plotting	SSPLOT
			PNPICO
			LEPICO
RESTART.dat	Binary	Output Restart File	RESTAR
RESTART.bin	Binary	Input Restart File	RESTAR
20	Binary	TSBOIL Data for Plotting	TSCMP0
			TSCMP1
21	Binary	DEFORM‑5 Plotting	DFORM5
22	Binary	EBR2 Reactivity Plotting	EBR2
23	Binary	FPIN2 Data for Plotting	FPNOUT
24	Binary	EBR-II Mark-V Safety Case Scratch Plotting Data File	TSPLOT
26	Binary	BOP Data for Plotting	LBPLOT
27	Binary	Steam Generator Data for Plotting	INIT, TSBOP
28	Binary	BOP Data for Plotting	INITS, TSBOP
29	Binary	BOP Data for Plotting	PLTBOP
MaxTemps.txt	Formatted	Summary of Maximum Temperatures in the Core	PRTMXT
MFUELss_ICH.dat	Binary	Summary of the MFUEL pre-transient irradiation predictions. Unique file for each channel using MFUEL is created.	MFUEL_SSInit
MFUELss_ICH-axial.dat	Binary	Axial summary of select MFUEL pre-transient irradiation predictions. Unique file for each channel using MFUEL is created.	MFUEL_SSInit
MFUELts_ICH.dat	Binary	Summary of the MFUEL transient predictions. Unique file for each channel using MFUEL is created.	MFUEL_SSInit