Document: NRC Regulatory Guide
Document ID: d35b20dd-1c15-4bc0-ab12-86d3766156f4
Document Type: regulatory_guide
Title: Withdrawing RG 1.41 because its guidance has been incorporated into RG 1.32, Revision 4
Source: NRC Regulatory Guide Division 1
Source URL: https://www.nrc.gov/docs/ML1427/ML14272A332.pdf
Revision Date: 2023-06
Chapter: 
Section ID: RG-1.41
CFR Part: 
CFR Title: 

Content:
onal testing of on-site electrical power systems important to safety, for load group assignments, electrical separation, and redundancy. Since that time, the Commission has amended its regulations for loss of all alternating current power (Station Blackout, § 50.63), loss of large areas of the plant due to explosions or fire (§ 50.54 (hh)(2)), and has established a new combined (construction and operating) licensing process (under Part 52). The Commission issued Order Environmental Assessment (EA)-12-049, “Order Modifying Licenses with Regard to Requirements for Mitigation Strategies for Beyond Design Basis External Events” which requires, in part, “licensees or construction permit holders shall develop, implement, and maintain guidance and strategies to maintain or restore core cooling, containment and SFP cooling capabilities following a beyond design basis external event,” and “these strategies must be capable of mitigating a simultaneous loss of all alternating current power and loss of normal access to the ultimate heat sink and have adequate capacity to address challenges to core cooling, containment, and Spent Fuel Pool (SFP) cooling capabilities at all units on a site subject to this Order”. Additional requirements in response to Fukushima lessons learned are in development. The current RG 1.41 recommends testing Class 1E electrical systems to verify that they are not cross-connected such that a single event could cause faults in multiple trains and that they are not cross-dependent such that a single event could cause the loss of required support systems for multiple trains. The RG does not address non Class 1E systems that may be required and used by station emergency procedures to respond to loss of all alternating current power (Station Blackout, § 50.63), loss of large areas of the plant due to explosions or fire (§ 50.54 (hh)(2)), and Order EA-12-049. 2. What is the impact on internal and external stakeholders of not updating the RG for