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:
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 calculations should account for the time dependence and spatial distribution of these variables. For example, superheated steam followed by saturated steam may be a limiting condition and should be considered. (2) For pressurized water reactors (PWRs) with a dry containment, LOCA or MSLB containment environment should be calculated using CONTEMPT-LT or equivalent industry codes. (3) For PWRs with an ice condenser containment, LOCA or MSLB containment environment should be calculated using LOTIC or equivalent industry codes. (4) For boiling water reactors (BWRs) with a Mark I, II, or III containment, LOCA or MSLB environment should be calculated using CONTEMPT-LT or equivalent industry codes. h. Section 7.2.6.1 of IEC/IEEE Std. 60780-323, Edition 1, 2016-02, should be supplemented with the following: The radiation environment for qualification of electric equipment should be based on the radiation environment normally expected over the installed life of the equipment plus that associated with the most severe design basis accident during or following which the equipment must remain functional. The accident-related environmental conditions should be DG-1361, Page 12 assumed to occur at the end of the installed life of the equipment. Methods acceptable to the NRC staff for establishing radiation doses for the qualification of equipment for BWRs and PWRs are provided in Appendix D and the following: (1) Electric equipment that could be exposed to radiation should be environmentally qualified to a radiation dose that simulates the calculated radiation environment (normal and accident) that the equipment should withstand prior to completion of its required safety functions. Such qualification should consider that equipment damage is a function of total integrated dose and can