A Method to Improve the Software Acceptance Criteria for Nuclear Power Plants

The license is a mandatory process required by a governmental authority and the certification is a voluntary process administrated by a professional community. A software certification is a result of an assessment that the certified software conforms to required criteria or standards. The certification is used as a committed promise to produce a high quality software, so software acquirers are requiring it from their suppliers. For example, US DoD (Department of Defense) requires an achievement of CMMI-SW (Capability Maturity Model Integration-Software) certification for participating in a major military software project. It is commonly said that the purpose of achieving a certification is to improve the product quality. In the nuclear area, a software certification has been rarely concerned with or required for the software used in a safety function of NPPs (Nuclear Power Plants). The safety critical software for NPPs is accepted by the nuclear regulators when the following three criteria are met: acceptable plans should be prepared to control the software development activities, the plans should be followed in an acceptable software life cycle, and the process should produce acceptable design outputs. The acceptance criteria are so abstractive that the nuclear regulators may assess the software development plans, activities, outputs based on their subjective engineering judgments. This is inevitable because a software has invisible or intangible characteristics. It is hard to assess the totality of a software prior to running it. These have caused the judgments to be biased. The regulators may want some objectiveness in assessing how much capability for software development the supplier possesses. In that case, the software certification can assist them for such an assessment. This paper proposes a method to improve the software acceptance criteria by applying the software certification to the criteria. This will assist the regulators to assess the supplier's software development capability. For this, the criteria should include the following certification requirements: software process, software engineers, and software product