Document: NUREG-0800
Document ID: 61ecb2ca-a7c2-4d16-bd86-57189f5d7175
Document Type: srp
Title: B-6
Source: NUREG-0800
Source URL: https://www.nrc.gov/docs/ML0705/ML070550087.pdf
Revision Date: 2023-06
Chapter: 7
Section ID: 7.1
CFR Part: 
CFR Title: 

Content:
th the organization responsible for the review of seismic qualification. Mild environment qualification should conform with the applicable guidance of IEEE Std. 323-1974, "IEEE Standard for Qualifying Class 1E Equipment for Nuclear Power Generating Stations." Additionally, the applicant/licensee should confirm that a single failure within the environmental control system, for any area in which protection system equipment is located, will not result in conditions that could result in damage to the protection system equipment, nor prevent the balance of the protection system not within the area from accomplishing its safety function. In this regard, the loss of an environmental control system is treated as a single failure that should not prevent the protection system from accomplishing its safety functions. Because the loss of environmental control systems does not usually result in prompt changes in environmental conditions, the design bases may rely upon monitoring environmental conditions and taking appropriate action to ensure that extremes in environmental conditions are maintained within non-damage limits until the environmental control systems are returned to normal operation. If such bases are used, the applicant/licensee should confirm that there is independence between environmental control systems and sensing systems that would indicate the failure or malfunctioning of environmental control systems. Review of mild environment qualification should also include confirmation that the environmental protection of instrument sensing lines conforms with the guidance of Regulatory Guide 1.151, "Instrument Sensing Lines."