RELAP5-3D Developmental Assessment Paul D. Bayless RELAP5 International Users Seminar July 2011

Developmental Assessment Overview Will be documented as Volume III of the code manual Written from a user’s perspective – Includes assessment judgments Has 53 assessment cases – 17 phenomenological problems – 27 separate effects experiments – 9 integral effects cases (8 experiments) Uses the AVscript capability in SNAP (pre-2.0 versions) Both semi- and nearly-implicit calculations performed for most cases Code manual is expected to be updated with each IRUG version release

Recent Activity Report has been extensively edited for consistency Some input models were modified to better represent the facility One case identified where the NRC Data Bank channels were mislabeled Neptunus model draining behavior showed need for a user guideline on modeling the surge line for a prizer component – Don’t connect a time-dependent volume directly to the pressurizer; donoring during outflow may be wrong

Legacy Assessment Cases Used to maintain code pedigree and for convenience Input models – Usually no documentation of the input model – May not conform to current modeling guidelines – May not use newer code features that would be used if the model were being developed today – Often not enough dimensional information on the experiment to allow the model to be changed Experiment data – Often have only the data shown in previous assessments – May not have a clearly defined trail back to the experiment – Often does not have measurement uncertainty information available

Ancillary Benefits Scripts have been altered to allow – Comparison of current assessment to previous – Comparison of one code version to another Assessment comparison – Allows quick visual indication of whether any assessment cases have changed significantly – Generates a document showing the comparisons Version-to-version comparison used to test a potential code update – Found that differences in the assessment case results did not support the update – The code was left unchanged

Status A couple of cases need to have their input models modified to conform to current modeling recommendations and then be re-run Waiting for the general release Fortran90 code version