Document: NUREG-0800
Document ID: 4b0fa4a0-ce32-4f59-9360-9426826a668c
Document Type: srp
Title: Rev. 4 — June 1997
Source: NUREG-0800
Source URL: https://www.nrc.gov/docs/ML0525/ML052500496.pdf
Revision Date: 2023-06
Chapter: 7
Section ID: 7
CFR Part: 
CFR Title: 

Content:
assumed should be consistent with the control system failure modes described in Section 7.7 of the SAR and the reactivity control interlock functions described in Section 7.6 of the SAR. Section 3(2) requires in part the identification of variables that are monitored in order to provide protective action. The tables in Sections 7.2 and 7.3 of the SAR should provide this information. Section 3(3) requires in part the identification of the minimum number and location of sensors for those variables in 3(2) that have a spatial dependence. The applicant/licensee's analysis should demonstrate that the number and location of sensors are adequate. Item 3 below discusses the consideration of the single failure criterion in the evaluation of this analysis. Sections 3(4), 3(5), and 3(6) require in part the identification of operational limits, the margin between operational limits, and the level for the onset of unsafe conditions (setpoint), and limits that require protective action (safety limit — i.e., value assumed in the safety analysis) for each variable. The applicant/licensee's analysis should confirm that an adequate margin exists between operating limits and setpoints, such that a low probability exists for inadvertent actuation of the system. The applicant/licensee's analysis should confirm that an adequate margin exists between setpoints and safety limits, such that the system initiates protective actions before safety limits are exceeded. Draft Reg. Guide DG-1045 (the proposed revision 3 to Reg. Guide 1.105, "Instrument Setpoints for Safety Systems") and BTP HICB-12 provide guidance on the establishment of safety system setpoints. The instrument performance data used in setpoint analyses should be consistent with the performance requirements established in the design basis as discussed in section 3(9). BTP HICB-6 provide specific guidance for determining if the timing margins for changeover from injection to recirculation mode are sufficient to allow manual