NAS's capabilities and experience cover the complete spectrum of software development services. In addition, the NAS Quality Assurance Program has been applied for the development and maintenance of safety-related software and for software analysis applications.

The NAS staff has authored, contributed to the development of, and modified programs used for thermal-hydraulic and physics analysis of nuclear plants. These programs include RETRAN, RELAP5, CHECWORKS, CORETRAN, TRAC, SIMULATE-E, CONTEMPT, PDQ7, SHUFFLE, KENO, ANISN, SIMTRAN, QUAD-P5A, DOT, SCALE, TOODEE2, and ASTEM.

NAS offers services in four general areas

• general mathematical model development for simulating physical processes,
• software design,
• software modifications and program conversions,
• software validation and verification.

Software Model Development

NAS specializes in developing and implementing mathematical models and software to simulate physical processes such as fluid flow, heat transfer, reactor physics. NAS can develop models to simulate a single phenomenon or complex systems consisting of several interacting components and processes. These models can be developed as standalone computer programs or they can be integrated into existing software. As contributing authors of several engineering programs, we have the proven capability to design and implement solutions to the special modeling needs of our clients.

Software Design

Successful software development projects begin with the software specification and design phase by detailing the functionality, data requirements, interactions, and performance requirements. These initial steps are followed by implementation, integration, and testing. We can help ensure the success of large or small software development projects by

• developing software specifications,
• designing software,
• implementing software,
• performing reviews of software design and code,
• writing test procedures, and
• integrating software.

Software Development

NAS is experienced in the use of the FORTRAN, C, and C++ programming languages. During the useful life of engineering software, the source code may require conversion to different computers or operating systems, modifications to analyze new applications, or features. NAS has significant experience maintaining and modifying engineering software including

• program conversion to other computers and operating systems,
• user convenience modifications,
• automated interface between codes
• model enhancements, and
• graphically oriented pre and post processors.

Software Verification and Validation

NAS staff members have served on review committees responsible for the independent verification and validation of several engineering analysis programs used for safety-related work. These include RETRAN-02, VIPRE-01, COBRA-SFS, HYDRA-II, FLOWTRAN, and GOTHIC. Specific areas where NAS can provide assistance include

• developing verification and validation plans,
• reviewing verification and validation plans, and
• performing verification and validation tasks.