BGS is committed to being at the forefront of providing engineering and technical solutions to clients in a wide range of activities. This requires our engineers and contractors to have access to the most important and cutting-edge computational tools available. Originally, BGS engineers primarily utilized the SCALE computational suite developed and maintained by the Oak Ridge National Laboratory, and in particular, the CSAS5 sequence in SCALE 6.2, which provides a three-dimensional multi-group and continuous energy eigenvalue Monte Carlo analysis. It is used to provide criticality safety analysis for clients, such as Four Rivers Nuclear Partnership, LLC, to aid in the deactivation and remediation activities at the Paducah Gaseous Diffusion Plant. However, as BGS expanded its scope of work further into nuclear safety analysis, fire safety, and other technological solutions for clients such as the Y-12 National Security Complex, the Pantex Plant, Oak Ridge National Laboratory, and the Savannah River Site, it became clear that the scope of the computational tools available to BGS engineers must also be expanded.
On its controlled server, BGS has installed or is in the process of installing, multiple new software packages this year. In addition to SCALE 6.2, BGS is adding MACCS2, a Gaussian plume model used for dispersion analysis developed and maintained by Sandia National Laboratories, CFAST, a two-zone fire modelling code developed and maintained by the Fire Research Division at the National Institute of Standards and Technology, and MathCAD, a mathematics software for engineering calculations. Each software package is given a share of the controlled server known as partitions, which act effectively as separate drives on the same server. On each partition, each software package is installed and undergoes verification and validation processes. Verification refers to the running of multiple sample inputs provided by the developer to ensure the software was installed on the BGS server correctly and that the resulting outputs match the outputs provided by the software developer. Software on the BGS server undergoes re-verification every six months to maintain functionality. Validation, on the other hand, is a more rigorous task in which benchmark (controlled real-world example) cases are modeled independently to ensure that the software results correlate to real-world applications. Validation is usually tailored toward benchmarks that are relevant to the work being performed for BGS clients. For example, the SCALE 6.2 validation covers only certain modules, such as CSAS5, certain cross-section groups, and even only certain enrichments of uranium and other factors relevant to the systems being modeled themselves. This means the validation must be amended to support work outside these parameters. Once verification and validation are completed, the software is deemed safe to run on the controlled server by qualified BGS engineers in order to carry out the necessary mission of each client. However, it is the configuration management plan which provides the framework to ensure it continues to be safe to use. Configuration management maintains records on the version of a particular software that is approved for use, provides the means through which to report non-conformances (i.e. discovered errors that would impede a tool’s ability to follow its approved protocol) and issues corrective actions such that the software remains available to BGS personnel, and ensures that necessary updates are completed within the same framework.
The computational tools mentioned earlier: SCALE, MACCS2, MathCAD, and CFAST have greatly expanded the ability of BGS to perform tasks such as modeling dose rates in dispersion analysis, ensuring criticality incredibility in long-term storage at deactivated nuclear sites, evaluating fire protection and suppression systems, and many more analyses. The addition of any software to the BGS toolbox is never as simple as installing it on a computer. It is a rigorous and heavily documented process, but it is necessary to maintain the commitment to safety and security that BGS provides for all its technical solutions.