Document: NRC Regulatory Guide
Document ID: b3436475-0452-4460-897e-ef2d0023a709
Document Type: regulatory_guide
Title: Guidelines for Lightning Protection of Nuclear Power Plants (Rev. 1)
Source: NRC Regulatory Guide Division 1
Source URL: https://www.nrc.gov/docs/ML2220/ML22208A232.pdf
Revision Date: 2023-05
Chapter: 
Section ID: RG-1.204
CFR Part: 
CFR Title: 

Content:
er. DG-1409, Page 4 B. DISCUSSION Reason for Revision Revision 0 of RG 1.204 was issued in November 2005 to endorse IEEE Std. 665-1995 (Ref. 1); IEEE Std. 666-1991 (Ref. 14); IEEE Std. 1050-1996 (Ref. 15); and IEEE Std. C62.23-1995 (Ref. 16). The IEEE standards 1050, 666 and C62.23 were revised in 2004, 2007 and 2017, respectively. This revision updates the RG to endorse IEEE Std. 665-1995; IEEE Std. 1050-2004; IEEE Std. 666-2007; and IEEE Std. C62.23-2017, with certain clarifications. Background Experience shows that lightning can pose operational threats to production and utilization facilities. Therefore, protection is essential to avoid malfunctions and upsets that, in turn, can lead to reactor trips. Nuclear power plants and other facilities should have a well-designed and properly installed lightning protection system (LPS) to safeguard their SSCs from lightning strikes and the resulting secondary effects. To protect against the effects of lightning strikes, the LPS should incorporate strike termination devices, discharge down conductors, and a grounding system. To protect against the secondary effects of lightning strikes, such as potentially disruptive surges and EMI/RFI that can propagate to internal structures and cause damage to safety-related systems, the LPS should also incorporate appropriate individual equipment grounding systems and surge protection devices (SPDs). The NRC staff has reviewed IEEE Std. 665-1995, IEEE Std. 666-2007, IEEE Std. 1050-2004, and IEEE Std. C62.23-2017 and determined that they are acceptable standards for lightning protection for production and utilization facilities. IEEE Std. 665-1995 (reaffirmed 2001) describes facility grounding practices and serves as the primary source of guidance on lightning protection for structures at power generating stations. As such, this standard identifies the grounding practices that the electric utility industry has generally accepted as contributing to effective grounding systems for