Document: NRC Regulatory Guide
Document ID: 4d46a966-d280-43da-9b03-8b0abe7b29ce
Document Type: regulatory_guide
Title: Alternative Radiological Source Terms for Evaluating Design Basis Accidents at Nuclear Power Reactors (Rev. 1)
Source: NRC Regulatory Guide Division 1
Source URL: https://www.nrc.gov/docs/ML2120/ML21204A065.pdf
Revision Date: 2023-05
Chapter: 
Section ID: RG-1.183
CFR Part: 
CFR Title: 

Content:
redit the piping addressed in that approval. Also, licensees that have not previously applied for such approval may do so in accordance with the guidance in Reference A-13 or using the revised seismic analysis method described below (derived from Reference A-14) for establishing a seismically rugged alternative drain path to the condenser. Licensees choosing either of these methods should define the alternative drain pathway to the main condenser and the basis for its reliability. The basis for reliability should include the qualification and redundancy of valves that must change position to establish the pathway, operator training, and procedures governing establishment of the alternative drain path as described in Regulatory Position A-5.4. Revised Seismic Analysis of the Alternative Drain Pathway All licensees choosing this alternative should describe the code of record used for the main steamlines and the extent of quality assurance measures applied to the design, materials, and fabrication of the steamlines and attached piping. The description should also include the alternate pathway identified to the main condenser and the basis for reliability of this pathway. In addition, the following information should be provided for the site, as applicable for the site seismic hazard tier: (1) If the piping and valves in the alternate pathway have been subjected to dynamic seismic analysis for the as-built configuration to a code of record (e.g., ASME B31.1, “Power Piping” (Ref. A-15)), and the magnitude of the seismic response spectrum for the analysis equals or exceeds the licensee’s SSE, a description of the dynamic analysis provides sufficient justification. (2) If the SSCs in the alternate pathway have not been subjected to dynamic seismic analysis to a code of record (e.g., ASME B31.1, “Power Piping”) and if the peak spectral acceleration of the ground motion response spectrum based on the licensee’s most recent site-specific probabilistic seismic