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RELAP5/RELAP5-3D Plug-in

The RELAP5 plug-in was designed to supports multiple versions of RELAP5 including RELAP5/MOD3.3 and RELAP5-3D versions 2.2, 2.3, 2.4, 2.6, 4.0 and 4.3. This plug-in is available to SNAP User's Group (SUG) members.

The RELAP5-3D© code was developed for best-estimate transient simulation of light water reactor coolant systems during postulated accidents. The code models the coupled behavior of the reactor coolant system and the core for loss-of-coolant accidents and operational transients such as anticipated transient without scram, loss of offsite power, loss of feedwater, and loss of flow. A generic modeling approach is used that permits simulating a variety of thermal hydraulic systems. Control system and secondary system components are included to permit modeling of plant controls, turbines, condensers, and secondary feedwater systems.

The RELAP5 Plug-in User's Manual provides instructions for working with RELAP5 models in SNAP. This Manual is also available as a searchable help set in SNAP.

Change Log

Version 4.8.1 - Released 10/4/2017:

  • The model options table in the model notebook export has been updated to write the text "Default Values" for the Print Controls when all the diagnostics are active, and no volume or junction controls are defined.
  • The model notebook export for the time dependent junction has been modified use “Time Dependent Data” as the section heading for its tabular data.
  • The model notebook export for time dependent volumes was updated to resolve an issue that prevented the Argon mass fraction from appearing in the table of noncondensable mass fractions.
  • The RELAP5 plot file parsing logic was updated to include new engineering units.
  • The following signal variables were added to RELAP5 3D Version 4.1 and 4.3: SYSTMBS, SYSTMBC, SYSTMFS, SYSTMFC, SYSTMGS, SYSTMGC, SYSTMNC, SYSTMNS, HTMWPOW, HTMWRQ, TFRONT, VFRONT
  • The error message indicating that a signal variable is not supported by the current version was updated to display the correct version number.
  • Heat structures have been modified to disable the inside cladding oxide thickness value for metal water reactions when the geometry is not set to rectangular. This only affects RELAP53D version 4.3 models.
  • The restart case logic was updated to exclude referenced variables from disabled properties from the list of replaced variables at the top of the ASCII restart case.
  • The model notebook ASCII export logic was updated to write h2o for the fluid type of the default hydraulic system.
  • The ASCII export and model notebook export logic for the print controls property of model options has been updated to export the diagnostics card when any volume or junction controls are present.
  • The model notebook export for the time dependent junction has been modified match the section heading format used for initial conditions of other hydraulic components.
  • The pump component reverse indicator property has been modified to support referencing an integer variable.
  • The restart case graphical editing logic was updated to resolve embedded variable references in the case ASCII with the preserve numerics case set to False. The variable references will be resolved when opening the case for graphical editing but when saving the case, references will be replaced with the current values.
  • The Ramona feedback nodal kinetics has been updated to resolve an issue where the Delayed Fiss Spec. editor would identify UNIX substitution variable references as invalid, unless their values summed to 1.0.
  • The nodal kinetics mesh lengths editing dialog has been updated to support variable references.
  • The RBMK feedback nodal kinetics has been updated to support variable references for the user variable values.
  • The preserve numerics logic for restart cases was updated to handle embedded variable references in the external function control block data.