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:
arge light-water reactors similar to those currently in operation. The methodology and assumptions described within may not be appropriate for other reactor designs, and the use of the methodology and specific assumptions described in this section for other reactor designs must be demonstrated to be appropriate for the specific application and will be evaluated on a case by case basis. In addition, all applicants may propose alternative methods to address environmental qualification (EQ) requirements. Regardless of the reactor design, consistent with Title 10 of the Code of Federal Regulations (10 CFR) section 50.49(e)(4), the methodology and assumptions for normal operation must be based on the total dose expected during normal operation over the installed life of the equipment, and the methodology and assumptions used for accident EQ must account for the radiation environment associated with the most severe design-basis accident for which the equipment is required to remain functional for the given reactor design. Therefore, the total integrated dose (i.e., the total of the normal operational and accident dose) for EQ must be based on the appropriate contribution of all significant radionuclides to which the equipment is exposed, considering the types of radiation (e.g., gamma, beta, and neutron radiation) and energy spectrum to which the equipment is exposed. As an alternative, a simplifying assumption may be used if the total integrated dose is justified to bound the total dose to the equipment and if sufficient margin is included to bound uncertainties associated with the assumptions. D-1. Normal Operations Radiation Dose The radiation environment resulting from normal operations should be based on the conservative source term estimates reported in the facility’s safety analysis report or should be consistent with the primary coolant specific activity limits contained in the facility’s technical specifications. The use of equilibrium primary coolant