RELAP5_channels.txt

Purpose

RELAP5_channels.txt maps elements of the RELAP5 thermal-hydraulic model to named communication channels used by the ADS-IDAC control panel. Together with ControlPanel.txt, it establishes the data links necessary to pass information between the RELAP simulation and the operator model.

Seven channel types are available. Each channel associates a name (used throughout ADS-IDAC input files) with a specific RELAP card or variable number.

Bidirectional communication

Only Interactive Control (IC_) channels allow ADS-IDAC to write values back to RELAP. All other channel types are read-only — they carry data from RELAP to the ADS-IDAC control panel but cannot modify RELAP variables.

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Channel Type Summary

Prefix	Type	RELAP Card Format	Direction	Notes
HV_	Hydraulic Volume	nnnxx0000 (9 digits)	RELAP → ADS-IDAC	nnn = volume number, xx = subvolume (usually 01 for single-subvolume components)
HJ_	Hydraulic Junction	nnnxx0000 (9 digits)	RELAP → ADS-IDAC	nnn = junction number, xx = subjunction (usually 00; use specific value for branch components)
VT_	Variable Trip	Trip number (nnnn)	RELAP → ADS-IDAC	Cards 401–599 (standard) or 1–1000 (expanded trip format). Useful for alarms and state indicators.
LT_	Logical Trip	Trip number (nnnn)	RELAP → ADS-IDAC	Cards 601–799 (standard) or 1001–2000 (expanded). Combines variable/logical trips using Boolean operators.
IC_	Interactive Control	Variable number (nnn)	ADS-IDAC ↔ RELAP	Cards 801–999 (standard) or 801–9999 (expanded). The only channel type that writes to RELAP. Used for controllable components such as pumps, valves, and actuation switches.
HS_	Heat Structure	cccg0nn (7 digits)	RELAP → ADS-IDAC	ccc = structure number, g = geometry, nn = axial node. Requires an additional mesh_point field.
CV_	Control Variable	Variable number (nnn or nnnn)	RELAP → ADS-IDAC	Defined by 205-series cards (205nnn000). Expandable to 1–9999 with optional extended format.

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Card Number Conventions

Hydraulic Volume (HV_)

The hv_card_number is a 9-digit integer of the form nnnxx0000, where nnn is the volume number (first three digits of the component definition card) and xx is the subvolume number.

INFO

Volume defined by card 2040000 → nnn = 204, single subvolume → xx = 01 → card number 204010000, channel name HV_204.

Hydraulic Junction (HJ_)

The hj_card_number is a 9-digit integer of the form nnnxx0000, where nnn is the junction number and xx is the subjunction number (typically 00).

INFO

Junction defined by card 2050000 → nnn = 205, xx = 00 → card number 205000000, channel name HJ_205.

Variable Trip (VT_)

The vt_trip_number is the integer trip number derived from the card number. Leading zeros are not required for numbers below 1000.

INFO

Variable trip card 0000450 → trip number 450, channel name VT_450. In expanded format, card 20604500 → trip number 450.

Logical Trip (LT_)

The lt_trip_number is the integer trip number. In expanded format, card 20616500 → trip number 1650.

Interactive Control (IC_)

The interactive_control_number is the 3-digit (or 4-digit in expanded format) variable number from cards 801–999.

INFO

Card 0000850 → variable number 850, channel name IC_850.

Heat Structure (HS_)

The hs_card_number is a 7-digit integer of the form cccg0nn. Each heat structure entry also requires a mesh_point (radial mesh point number) on the same line.

INFO

Heat structure card 12051000, axial node 5 → hs_card_number = 2051005. Channel name HS_85008 corresponds to node 8 of heat structure 850.

Control Variable (CV_)

The control_variable_number is the 3-digit (or 4-digit) number from the 205-series card.

INFO

Control variable card 20553500 → variable number 535, channel name CV_535.

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Input File Format

Each channel is one line; section names below match the shipped reference file tests/BV4/Input/System/RELAP5_channels.txt. The parser is token-based (line breaks and other whitespace are interchangeable, and section header words are not validated — order and counts drive parsing):

Control_volume             number_of_hydraulic_volumes
hydraulic_volume_name_1    hv_card_number_1
.
hydraulic_volume_name_n    hv_card_number_n

Control_junction           number_of_hydraulic_junctions
hydraulic_junction_name_1  hj_card_number_1
.
hydraulic_junction_name_n  hj_card_number_n

Variable_trips             number_of_variable_trips
variable_trip_name_1       vt_trip_number_1
.
variable_trip_name_n       vt_trip_number_n

Logical_trips              number_logical_trips
logical_trip_name_1        lt_trip_number_1
.
logical_trip_name_n        lt_trip_number_n

Interactive_controls       number_of_interactive_controls
interactive_control_name_1 interactive_control_number_1
.
interactive_control_name_n interactive_control_number_n

Heat_structure             number_of_heat_structures
heat_structure_name_1      hs_card_number_1  mesh_point_1
.
heat_structure_name_n      hs_card_number_n  mesh_point_n

Control_variables          number_of_control_variables
control_variable_name_1    control_variable_number_1    units_1
.
control_variable_name_n    control_variable_number_n    units_n

INFO

If a channel type is not used, set its count to 0 and omit the associated name/number entries entirely.

Control variable field order

A control variable line reads name, then number, then units — e.g. CV_002 002 Seconds. The units string is the third field, not part of the name line; a missing or extra units token shifts every following entry.

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Parameter Reference

Parameter	Format	Description
number_of_*	Integer ≥ 0	Count of channels in the section. Set to 0 to omit the section.
*_name	String (no spaces)	Channel identifier used in ADS-IDAC input files. Use _ in place of spaces.
hv_card_number	9-digit Integer	RELAP hydraulic volume component card number (nnnxx0000).
hj_card_number	9-digit Integer	RELAP hydraulic junction card number (nnnxx0000).
vt_trip_number	Integer	Variable trip number (401–599 standard, 1–1000 expanded).
lt_trip_number	Integer	Logical trip number (601–799 standard, 1001–2000 expanded).
interactive_control_number	Integer	Interactive variable number (801–999 standard, 801–9999 expanded).
hs_card_number	7-digit Integer	Heat structure card number (cccg0nn).
mesh_point	Integer	Radial mesh point number for the heat structure channel.
control_variable_number	Integer	Control variable number (1–999 standard, 1–9999 expanded).
units	String (no spaces)	Units of the control variable quantity. Use _ in place of spaces. Note: RELAP outputs SI units unless the card converts to another system.

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Sample Input

This sample defines 2 hydraulic volume channels, 3 hydraulic junction channels, 1 variable trip, 1 logical trip, 4 interactive controls, 1 heat structure, and 8 control variable channels.

Control_volume             2
HV_204                     204040000
HV_953                     953010000

Control_junction           3
HJ_527                     527000000
HJ_627                     627000000
HJ_727                     727000000

Variable_trips             1
VT_0465                    465

Logical_trips              1
LT_1507                    1507

Interactive_controls       4
IC_801                     801
IC_802                     802
IC_803                     803
IC_804                     804

Heat_structure             1
HS_57001                   5701001    8

Control_variables          8
CV_002                     002    Seconds
CV_100                     100    %
CV_101                     101    F
CV_477                     477    Watts
CV_515                     515    gpm
CV_519                     519    gallons
CV_984                     984    lbm/s
CV_864                     864    rpm

The RELAP input deck associated with this problem must define all referenced volumes, junctions, trips, interactive variables, heat structures, and control variables, or errors will be generated during input file processing.