Document: NUREG-0800
Document ID: fe8ec6c2-e960-404c-854f-55c77bde1672
Document Type: srp
Title: NUREG-0800
Source: NUREG-0800
Source URL: https://www.nrc.gov/docs/ML2400/ML24005A077.pdf
Revision Date: 2024-05
Chapter: 7
Section ID: 7
CFR Part: 
CFR Title: 

Content:
ceptable consequences. BTP 7-19-18 Revision 9 — May 2024 Although a spurious operation is not always anticipated, it can be detected, because this type of failure is normally self-announcing through instrumentation on the actuated system. However, in some circumstances, a spurious operation may not occur until a particular signal or set of signals is present. In these cases, rather than occurring immediately upon system startup, the spurious operation would occur only under certain plant conditions. Such a spurious operation is still self-announcing (by the actuated system), even if failure did not occur on initial test or startup. Because of the potential consequences of a spurious operation, a system’s failure to actuate might not be the most limiting failure. This is especially true in view of the time needed to identify and respond to conditions resulting from spurious operation in DI&C systems. In some cases, a failure to trip might be less limiting than a partial actuation. For example, a partial actuation of an emergency core cooling system (i.e., spurious operation of a single division), together with a false indication of a successful actuation, may take an operator longer to evaluate and correct than a total failure to send any actuation signal would. Therefore, the reviewer should consider the possibilities of both partial actuation and total failure to actuate, together with false indications, stemming from a CCF. Sources of Spurious Operation Spurious operations originating from CCFs due to latent design defects are considered beyond design-basis events and are within the scope of this BTP.8 As stated in the background section of this BTP, CCFs should be evaluated in a manner consistent with SRM-SECY-22-0076. Therefore, the reviewer may apply the methodologies described in this BTP when evaluating spurious operations resulting from CCFs. Spurious Operation and Interconnected Systems As stated in the background section of this BTP, the