STARCode Analysis Tools

Polestar has developed and maintains a set of proprietary analysis codes under the company’s 10CFR50 Appendix B Quality Assurance program. These codes include:

> STARNAUA
> STARpH
> STARDOSE

Polestar also makes use of the NRC’s RADTRAD code and has contributed to its development; however, it is precisely because of the independence of its own analysis tools that some of the RADTRAD shortcomings were identified.

STARNAUA is a safety-related code that analyzes activity transport in particulate form. Since the major portion of the Alternate Source Term (AST) is particulate (a substantial change from the current TID-14844 source term), new methods are needed to characterize the transport. While such calculations are also performed within RADTRAD (the NRC’s AST dose calculation code that uses internally-calculated transport and removal coefficients), RADTRAD overlooks many important transport phenomena and does not provide for sufficiently plant-specific modeling. In supporting the review of the Perry AST submittal (the first application of AST to an operating plant), Polestar persuaded NRC to replace many of RADTRAD’s internally-calculated transport and removal coefficients with Polestar-calculated values at the input level, thus permitting NRC to come much closer to Polestar’s final result.

STARpH is a safety-related code that analyzes suppression pool pH as a function of time for systems containing radiolytically-generated strong acids and a variety of buffers and bases that may be used to control pH. Without pH control and an evaluation establishing that post-accident containment sump pH remains above 7, the advantages of AST may be lost due to re-evolution of radioiodine in elemental form.

STARDOSE is a safety-related dose-integration code. STARDOSE is a generalized model that permits a large number of control volumes, junctions, activity removal rates, filter efficiencies, decontamination factors, etc. to be specified. Because STARDOSE is so generalized, it is very flexible. For example, Polestar has completed a PWR AST study in which it was necessary (as a beginning step) to benchmark against an existing dose calculation which includes three contributions:
 
· A coolant-activity release from a potentially open containment purge valve
· An elemental iodine release from ESF leakage
· TID-14844 source term leakage from sprayed and unsprayed regions of the containment.

The existing analysis required three separate models; the Polestar STARDOSE model requires only a single model to include all three contributions.

For more information contact:
Jim Metcalf
(603) 380-3938