Document: NRC Regulatory Guide
Document ID: 9547afbc-5a01-4bff-a41f-8300f5ba922b
Document Type: regulatory_guide
Title: Condition Monitoring Techniques for Electric Cables Used in Nuclear Power Plants
Source: NRC Regulatory Guide Division 1
Source URL: https://www.nrc.gov/docs/ML1007/ML100760364.pdf
Revision Date: 2023-06
Chapter: 
Section ID: RG-1.218
CFR Part: 
CFR Title: 

Content:
nergized medium-voltage cables, and all types of cable insulation and jacket materials. The IB inspection technique is essentially an optically enhanced visual inspection using the IB tool to visually access cables in otherwise inaccessible conduits and ducts to assess their physical appearance and condition and to identify and locate water intrusion or contamination in the conduits or cable ducts. The IB test is capable of detecting aging mechanisms such as mechanical damage, potential for moisture intrusion, and surface contamination. Advantages of the IB test are that the test is relatively easy to implement and can be performed on inaccessible cables to detect the presence of stressors or cable damage and degradation. The disadvantage of the IB test is that it does not provide quantitative data that can be trended. 4. Visual Inspection The visual inspection technique for accessible cables is a very simple yet extremely powerful cable condition monitoring technique for evaluating cable system aging because physical damage and many degradation mechanisms are readily detectable through sight. Visual inspection can be used to identify changes in physical/visual appearance, surface texture, and damage. Flashlights or magnifiers can aid visual inspection. DG-1240, Page 6 The advantages of visual inspection are that it is easy to perform, it is minimally intrusive and nondestructive, and it can easily detect degradation because of locally adverse conditions. The disadvantages are that the cables to be inspected must be visible and accessible; results are not quantitative, making trending very difficult; and appearance is subjective and observations can vary from inspector to inspector. 5. Compressive Modulus (Polymer Indenter) This technique is a mechanical properties (hardness) technique that is applicable to polymer jacket and insulation materials, such as polyethylene, EPR, chlorosulphonated polyethylene, and neoprene, used for low-voltage cables. The compressive