Document: NRC Regulatory Guide
Document ID: 31f5b507-4290-458f-9233-049d79b5ff59
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:
Advantages of the test are that it is relatively easy to perform, it does not require access to the entire cable, it does not need to be corrected for temperature effects, and it can provide trendable data. The disadvantages are that the end terminations of the cable must be disconnected to perform the test, the test is not as sensitive to insulation degradation as other electrical properties techniques, and leakage currents are very small and sensitive to surrounding environmental conditions, making it difficult to measure accurately. 8. Partial Discharge Test The partial discharge test (PDT) is a diagnostic test that applies to medium-voltage shielded cables and all types of cable insulation and jacket materials. Aging mechanisms detected by the PDT include thermally induced embrittlement and cracking, mechanical damage, radiation-induced embrittlement and cracking, and water treeing. Advantages of the PDT are that it does not require access to the entire length of the cable, it identifies the significant partial discharge sites in an insulation system, it provides information on the severity of the insulation defects, and it gives information on the location of each of the significant partial discharge sites (and insulation defects). Disadvantages are that the end terminations of the cable must be disconnected to perform the test, performance of the PDT is complex and requires a high skill level, the interpretation of PDT results requires a very high skill level and training, and the high testing voltage applied during the PDT has the potential to weaken and permanently damage the cable insulation. Also, nearby operating electrical equipment in a plant environment could cause noise interfere with the test, so this test is most successful on shielded cables. 9. Time Domain Reflectometry The time domain reflectometry (TDR) test is a diagnostic test that can be implemented on low- and medium-voltage cables and all types of cable insulation and jacket materials. The