Document: NRC Regulatory Guide
Document ID: 4056a39f-0c52-46d1-b8d4-097c0827389f
Document Type: regulatory_guide
Title: Spray Pond Piping Made from Fiberglass-Reinforced Thermosetting Resin (Rev. 2)
Source: NRC Regulatory Guide Division 1
Source URL: https://www.nrc.gov/docs/ML0037/ML003740253.pdf
Revision Date: 2023-06
Chapter: 
Section ID: RG-1.72
CFR Part: 
CFR Title: 

Content:
itions, the qualifica tion procedures may not result in. a design factor of 6, and it is therefore necessary to perform an additional short-time cyclic and burst test to ensure that the desired design factor is obtained. Failure is defined in ASTM D-2992 as either leaking, weeping, or bursting. Whichever of these occurs first defines failure. General guidance for loading combinations relative to design limits for Class 3 piping may be found in Regulatory Guide 1.48, "Design Limits and Loading Combinations for Seismic Category I Fluid System Components." How ever, specific equations and limits from Code Case N-155 are not addressed in Regulatory Guide 1.48. Normal commercial practice provides a weather-resistant coating to the exterior of RTR piping that will be exposed to weather conditions. Experience has shown that this practice provides adequate protection for the service considered in this guide. Distribution of resin is generally such that more resin Is applied to the exterior of the pipe than to the interior, and part of the outer resin may have special properties to protect the underlying material from deleterious effects from sources such as ultraviolet radiation and weather. RTR piping has been used to distribute cooling water to nozzles in spray ponds. It Is desirable to provide weather protection to such piping. However, the omission of an exterior protective coating would be acceptable for piping installed in covered but accessible trenches, provided the inservice inspection frequency is increased to require visual inspection for leaks of all such piping at least once every year. Limited information is available on the effects of radiation on laminates (fiberglass and resin materials bonded together). However, short time exposure tests have been made, and they showed no appreciable change in the tensile strength of the pipe test piece. For cooling water application,. there appears little opportu nity for radiation exposure, and the piping should be