Document: NRC Regulatory Guide
Document ID: e16da529-b6b4-4fdf-bc3f-7490180363f3
Document Type: regulatory_guide
Title: Environmental Qualification of Certain Electric Equipment Important to Safety for Nuclear Power Plants (Rev. 2)
Source: NRC Regulatory Guide Division 1
Source URL: https://www.nrc.gov/docs/ML2018/ML20183A423.pdf
Revision Date: 2023-06
Chapter: 
Section ID: RG-1.89
CFR Part: 
CFR Title: 

Content:
fe) could also adversely impact the qualified life. DG-1361, Page 11 Therefore, the following definition of “service life” should be used instead of the definition in Section 3.22 of IEC/IEEE Std. 60780-323, Edition 1, 2016-02: “period from initial operation to final withdrawal from service of a structure, system, or component.” Note: The period before the operational phase of the structure, system, or component (i.e., shelf life), could also adversely impact the qualified life and, therefore, should be addressed. e. Paragraph 4 of Section 5.1 of IEC/IEEE Std. 60780-323, Edition 1, 2016-02, notes that “Requirements, including EMC [Electromagnetic Compatibility], environmental/operational ageing and seismic requirements shall be specified in the design/purchase specifications.” The prerequisite for aging electric equipment located in a mild environment is not within the scope of 10 CFR 50.49. Therefore, this sentence should be amended as follows: “Requirements, including EMC and seismic requirements, shall be specified in the design/purchase specifications.” f. Condition monitoring and associated condition-based qualification methodologies discussed in Section 6.3 of IEC/IEEE Std. 60780-323, Edition 1, 2016-02, represent new approaches for extending or establishing the qualified life of electrical equipment. If used, these methodologies must ensure that equipment important to safety will perform under the conditions specified in 10 CFR 50.49. g. Section 7.2.6 of IEC/IEEE Std. 60780-323, Edition 1, 2016-02, should be supplemented with the following: Temperature and Pressure Conditions Inside Containment for a LOCA and Main Steam Line Break (MSLB). The following methods are acceptable to the NRC staff for calculating and establishing the containment pressure and temperature envelopes to which equipment should be qualified: (1) Methods for calculating mass and energy release rates for LOCAs and MSLBs are referenced in Appendix C to this guide. The