Document: NUREG-0800
Document ID: 96afb1d6-6ce9-41e4-b4ec-1fc7747bc0b2
Document Type: srp
Title: Revision 8 – January 2021
Source: NUREG-0800
Source URL: https://www.nrc.gov/docs/ML2033/ML20339A647.pdf
Revision Date: 2023-05
Chapter: 7
Section ID: 7
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Content:
se Failure from Further Consideration CCF vulnerabilities in DI&C systems or components have two general causes: (1) errors BTP 7-19-21 Revision 8 – January 2021 introduced by the system hardware or software design, and (2) errors or defects introduced during the development and integration of the software, hardware, or software-based logic. When designing an I&C system, the applicant might use a robust (high-quality) development process, in conjunction with thorough system analysis (e.g., failure modes and effects analysis, system theoretic process analysis), to correct many potential design errors in the requirements or specifications for both analog and digital equipment. However, even a high-quality development process cannot completely eliminate latent design defects introduced during the design and integration process. Thorough testing can help to identify latent design defects in DI&C systems, provided the design is simple enough to allow such testing. Testing can be used to uncover latent design defects for correction in the design process and to demonstrate that any identified latent design defects have been corrected. The reviewer should determine whether testing of the proposed DI&C system or component shows that all latent design defects have been identified and corrected, so that the system or component will function as specified under the anticipated operational conditions. If so, the CCF can be eliminated from further consideration. The applicant may use various testing methods, which the reviewer should consider on a case-by-case basis. In each case, the reviewer should consider whether the technical basis for these testing methods is acceptable. Acceptance Criteria If the acceptance criteria below are met, the reviewer should conclude that the application provides sufficient information on the test results and testing methodology for a device or component to eliminate a potential CCF from further consideration. The acceptance criteria are as