Document: NUREG-0800
Document ID: 853719df-a6ea-408b-8d43-5956155abc38
Document Type: srp
Title: and 8.3.2.
Source: NUREG-0800
Source URL: https://www.nrc.gov/docs/ML1007/ML100740246.pdf
Revision Date: 2023-06
Chapter: 8
Section ID: 8.3.1
CFR Part: 
CFR Title: 

Content:
onsite power sources. It is also important that provisions for an AAC source will not adversely affect performance of offsite or onsite power system functions. AAC power sources located at or near the plant should conform to guidance provided in RG 1.155 concerning their capacity, capability, and physical independence from onsite safety-related systems and the preferred power system. See SRP Section 8.4 for details of the review of AAC power sources for SBO. For passive reactor design applications, such as the AP 1000, the potential risk contribution of an SBO is minimized by not requiring ac power sources for DBEs. The safety-related passive systems in these plants do not need non-safety-related ac power sources to perform safety-related functions. They are designed to automatically establish and maintain safe shutdown conditions after DBEs for 72 hours, without operator action, following a loss of both onsite and offsite ac power sources. Consequently, passive reactor designs meet the requirements of 10 CFR 50.63 for 72 hours. Meeting the requirements of 10 CFR 50.63 provides assurance that the nuclear power plant can be able to withstand or cope with, and recover from an SBO and will ensure that core cooling and appropriate containment integrity are maintained. 8. 10 CFR 50.65 (a)(4) requires that licensees assess and manage the increase in risk that may result from proposed maintenance activities before performing the maintenance activities. Grid stability and offsite power availability are examples of emergent conditions that may result in the need for action prior to the conduct of the assessment or that could change the conditions of a previously performed assessment. Accordingly, licensees should perform grid reliability evaluations as part of the maintenance risk assessment before performing Agrid-risk-sensitive@ maintenance activities (such as surveillances, post-maintenance testing, and preventive and corrective maintenance). Such activities are those