2012:35 Technical Note, Review of SKB’s Code Documentation and QA for the SR-Site Safety Assessment

This initial review examined the Swedish Nuclear Fuel and Waste Management Company (SKB) code documentation and quality assurance, which is important to the safety assessment SR-Site because the computer codes used must be both suitable for the analyses performed and capable of producing accurate results for those analyses.  SKB has prepared a report that summarizes the code documentation available for the codes used and the quality assurance processes applied to those codes.  The review to determine whether SKB’s code documentation and quality assurance is adequate focused on SKB’s model summary report (MSR) and other documents that are identified in the MSR.

SKB used 22 codes in developing its safety case in SR-Site.  The MSR addresses three categories:  (i) commercial codes:  ABAQUS, CODE_BRIGHT, ConnectFlow, Ecolego, ERICA Tool, MATLAB, MIKE SHE, PHAST, PHREEQC, and TOUGHREACT; (ii) modified commercial codes:  3DEC, ABAQUS, and CODE_BRIGHT; and (iii) project-specific codes:  Analytical model for quantification of buffer erosion and canister corrosion, DarcyTools, FARF31, MARFA, MATLAB–COMP23,
MATLAB–FPI, MATLAB–Pandora, Numerical GIA model, Numerical permafrost model, Solubility model (Simple Functions), and UMISM.  SKB used several versions of some codes and made several modifications to commercial codes for their use.

The review found that the amount of information and the value of the information varied widely among the codes.  Some codes are well documented and the documents provide good confidence that the codes are suitable and capable to perform the analyses.  However, the information for about one-half of the codes does not clearly describe how the code is capable of producing accurate results.  Also, several codes do not meet SKB standards for developing codes which if followed would assure that they perform properly.