Document: NRC Regulatory Guide
Document ID: 0b9a3243-ab39-402c-9f4b-215c6e4f79ab
Document Type: regulatory_guide
Title: Inservice Inspection of Ungrouted Tendons in Prestressed Concrete Containments (Rev. 3)
Source: NRC Regulatory Guide Division 1
Source URL: https://www.nrc.gov/docs/ML0037/ML003740007.pdf
Revision Date: 2023-06
Chapter: 
Section ID: RG-1.35
CFR Part: 
CFR Title: 

Content:
ainments that differ from these two types, the program described should serve as the basis for the development of a comparable inservice inspection program. 1.3. The inservice inspection should be per formed 1, 3, and 5 years after the initial structural integrity test (ISIT) and every 5 years thereafter. 1.4. Containments should be designed and con structed so that the prestressing anchor hardware is accessible for inservice inspection. 1.5. All containment structures with ungrouted tendons should be inspected in accordance with this guide. However, the liftoff force comparison may be performed as shown in Figure 1 if any two contain ments at the same site are shown to satisfy all three of the following conditions: a. The containments are identical in all aspects such as size, tendon system, design, materials of construction, and method of construction. b. Their ISITs were performed within two years of each other. c. There is no unique situation that may subject either containment to a differ ent potential for structural or tendon deterioration. For both containments, the visual and filler grease inspection should be performed according to Regulatory Positions 3 and 6 at frequencies described in Regulatory Position 1.3. 2. SAMPLE SELECTION 2.1. For the inspections at 1, 3, and 5 years, 4% of the population of each group (vertical, hoop, dome, and inverted U) of tendons should be selected randomly with a minimum of four tendons from each group. The sample size from any group need not ex ceed ten. 2.2. If the inspections performed at 1, 3, and 5 years indicate no abnormal degradation of the post tensioning system, 2% of the population of each group (vertical, hoop, dome, and inverted U) of ten dons or five tendons, whichever is less, may be se lected for the subsequent inspection with a minimum of three tendons for each group. 2.3. The fraction obtained as a percentage of a tendon population should be rounded off to the near est integer. 2.4. The tendons to be