Model-based Software Development Process with CASE Tool for NPP Safety Systems

摘要

With the ISODE, "V c ycle" in the software development lifecycle transforms to the "Y c ycle". According to the reference, this process has the time and cost savings, depending on the lifecycle. If the "Y cycle" with qualified Code Generator as a de velopment tool is taken, compliance of the code to the low-level requirements is guaranteed and the corresp onding verification activities may be reduced. In the ISODE, the requirements and design requirements are written in formal models. The models written with formal specifications are capable of analyzing functions on a mathematical foundation. Therefore, the incompleteness, inconsistencies, and incorrectness of the software can be detected and prevented in the design phase of the software lifecycle phases. The developers and verifiers can easily understand the software structure because the formal specification language is used. Therefore, it is possible to conduct more strict verification and validation to eliminate human errors. Since the requirement documentation and de sign are co nducted simultaneously, errors can be fixed at the same time through modeling and simulation. A verified code generator substitutes the entire manpower needed for source code generation by automatically generating source code and prevents the potential of various human errors from manual code generation. Semantics checks are performed statically in verification and v alidation phase using the check ers provided from formal specification tools. Also, unintended functions can be eliminated through coverage analysis required by the requirements and it is convenient to perform an MC/DC coverage analysis with the help of the tools. The software development documents automatically generated from using ISODE always reflect the latest design. If there is no m ismatch between t he existing requirement documents and the i mplemented software, additional document development manpower is not needed. Finally, KEPCO E&C suc cessfully implemented and tested the PPS, QIAS-P software for SHN 1&2 NPP and sent them to site March, 2015.