The assessment of the condition of low-voltage instrumentation, control, and power cables in nuclear power plants (NPP’s) is of increasing importance as plants age and lifetime is extended.
Furthermore, as new reactors are being constructed, effective in-situ condition monitoring (CM) techniques to follow cable condition indicators from the beginning, can be valuable for cable lifetime management.
At NPP’s two basic types of thermal and radiation aging of cables are of concern: bulk (global) aging, where the degradation is distributed over the cable length, and local aging (hot spots), where a localized heat or radiation source, such as a hot pipe, is close to the cable tray or conduit. Such local adverse environmental stressors can cause excessive aging in the exposed sections of a cable that could significantly shorten its effective service life and cause unexpected early failures.
LIRA® is a non-destructive, full length and in-situ CM technique with the capabilities of:
- Electrical assessment of nuclear cables used in the field to determine the current condition of installed cables over the entire length: global aging and hot spot assessment.
- Predict Remaining Useful Life (RUL), including the establishment of acceptance criteria and correlation of physical cable properties to electrical properties.
- Correlate condition indicators of cables near the end of life with accident (DBE) survivability.
- Investigate new cables and perform fingerprint reference measurement, e.g. input to Asset Management.
- Detect degradations due to temperature, radiation, corrosion, water intrusion, scratches, bends, mechanical impacts, fatigue, water trees, etc.