Document: NUREG-0800
Document ID: be3ce44f-6784-4f40-baef-12c96ec1ff96
Document Type: srp
Title: provides additional guidance on digital data communications systems.
Source: NUREG-0800
Source URL: https://www.nrc.gov/docs/ML0706/ML070670183.pdf
Revision Date: 2023-06
Chapter: 7
Section ID: 7.9
CFR Part: 
CFR Title: 

Content:
) should be produced. The code should include all of the functional and process characteristics listed below. B.3.3.4.1 Functional Characteristics of CL For each of the functional characteristics, the requirements imposed on the software for that characteristic should be satisfied by the code. Functional characteristics addressed by the code documents should include accuracy, robustness, safety, and timing. Accuracy means that the actual source code is written so that the accuracy requirements and accuracy design specifications are met. In particular, special care should be taken for floating point arithmetic, round-off errors, and the retention of precision during numerical operations. If mathematical subroutine libraries are used, the accuracy characteristics of the subroutines should be known and documented, and shown to meet the accuracy requirements and accuracy design specifications. Robustness means that the system is coded in such a way that corrupted data will not cause the safety system to fail. Data corruption should be avoided. All input data should be checked to ensure that the correct data is being read and that the data is in the correct format. All messages should be checked to ensure that the correct message is being read and that the message contents are in the correct format. Appropriate corrective actions should take place if any of these criteria are violated. Safety means that the code introduces no new hazards into the safety system. Security means that the code introduces no new security threats into the safety system software. Timing means that the execution time is deterministic. SRP BTP 7-21 provides additional guidance on real-time performance. BTP 7.14-60 Revision 5 - March 2007 B.3.3.4.2 Process Characteristics of CL Software development process characteristics exhibited by the code documents should include completeness, consistency, correctness, style, traceability, and verifiability. Completeness means that the code meets all the