Document: NUREG-0800
Document ID: f1629507-6318-4e71-94a6-9d6664ba96a3
Document Type: srp
Title: of the plant safety analysis report (SAR).  Although NRC did not endorse the annexes of
Source: NUREG-0800
Source URL: https://www.nrc.gov/docs/ML0706/ML070660327.pdf
Revision Date: 2023-06
Chapter: 7
Section ID: 7.6
CFR Part: 
CFR Title: 

Content:
eration • Maintenance • Retirement. The activities during the lifecycle phases are summarized as: • Creating the conceptual design of the system, translation of the concepts into specific system requirements • Using the requirements to develop a detailed system design • Implementing the design into hardware and software functions • Testing the functions to assure the requirements have been correctly implemented • Installing the system and performing site acceptance testing • Operating and maintaining the system • Retiring the system. SRP BTP 7-14 describes the characteristics of a software development process that the NRC staff evaluates when assessing the quality criteria of the entire Clause 5.3 of IEEE Std 7-4.3.2-2003. Software characteristics can be divided into two sets: functional characteristics and software development process characteristics. The first set includes those characteristics that directly relate to the actions that the safety system software should take, while the second includes those characteristics of the software development process that contribute to assurance that the software will perform the required actions. Both sets are important in safety system software. The sets, and the definitions of the characteristics, are listed below. Functional Characteristics: • Accuracy — The degree of freedom from error of sensor and operator input, the degree of exactness exhibited by an approximation or measurement, and the degree of freedom from error of actuator output. • Functionality — The operations which must be carried out by the software. Functions generally transform input information into output information in order to affect the reactor operation. Inputs may be obtained from sensors, operators, other equipment, or other software. Outputs may be directed to actuators, operators, other equipment, or other software. • Reliability — The degree to which a software system or component operates without failure. This