Electrical Cable Aging and Condition Monitoring Codes and Standards for

Nuclear Power PlantsElectrical Cable Task Group (ECTG)

Co-Chairs:Dr. Stephanie Watson, NIST Corey McDaniel, R-SCC

ECTG Scope

Objectives:

Inventory of relevant standards with gaps and overlaps analysis.

Recommendations for revisions or new electrical cable

standards.

Review of current citations of electrical cables codes and

standards in NRC regulatory documents.

Recommendations for research that is needed.

Gaps in Research (Previously discussed; still relevant)

1. Determination of aging mechanisms

a. Low voltage cable under wet conditions

b. High voltage cables under temperature, radiation, and wet conditions

c. Accident condition qualification

d. Newly developed insulation materials

2. Determination of extended service life of aged cables

3. Determination of the effectiveness of cable splicing and aging process

4. Standardization of procedures for condition monitoring test methods

a. Calibration of equipment and optimization of test parameters

b. Development and optimization of acceptance criteria

Priority NRC Regulatory DocumentsRecommendation: Revise RG 1.218, Condition Monitoring Techniques for Electric Cables Used in Nuclear Power Plants (Revision 0, April 2012).

a. Include Transmission & Distribution (T&D) Techniques, such as dielectric spectroscopy, on-line partial discharge, VLF.

b. Discuss caveats of Cable Indenter

• Acceptable for elastomer polymers, but NOT reliable for semi-crystalline polymers like PE and XLPE

• Complex results for multi-component/multi-polymer cables

c. Clarify DC HiPot procedure- potentially harmful influence with degree of degradation

d. Note that EPRI guides -1020804, 1020805, and 1021629 are being used by US NPPs for programmatic and condition monitoring techniques.

e. Caution about applying any single diagnostic to achieve the goal

Priority NRC Regulatory Documents (Continued)

2. Recommendation: Revise RG 1.89 “Environmental Qualification of Certain Electric Equipment Important to Safety for Nuclear Power Plants” (Revision 1, June 1984)• Update reference to IEEE 323-2003.

3. Recommendation: Revise RG 1.189 “Fire Protection for Nuclear Power Plants (Revision 2, October 2009)• using recent versions of IEEE 323 and IEEE 1202.

Question: Even if we determine that new or revised standards are needed, how will the changes be driven? SDOs have processes for revisions; revisions are not always from emerging technical issues or demands of users.

Gaps in Research and Standards1. Cable Aging Studies

a. Accelerated aging and extrapolation to 60 yearsi. Thermal and radiation sequenceii. Diffusion limited oxidation

2. Water Submergence and its Effectsa. Medium versus low voltage

3. Activation Energy Determination

4. Adequacy of Cable Characterization Techniquesa. Destructive versus non-destructiveb. Line Resonance Analysis (LIRA)

i. Low voltage cable applications; SDOs need to develop a methodii. Currently used in NPPs (I&C, power), T&D, Wind Parks (on/offshore), Process Industry, Oil

and Gas Industry (above ground, underground, submarine, umbilical cables), Cable Manufacturers (reference measurements, QC)

c. Joint Time and Frequency Domain Reflectometryd. Cable field tests for non-shielded cables (5 kV and above)

5. Universal procedure for walk-downs of cable installations

Existing NPPs

Gaps in Research and Standards

1. Qualification testing on low smoke zero halogen cables

2. Performance correlation between fast non-oxidative diffusion limited

oxidation controlled exposure (IEEE 323) with oxidatively driven materials

degradation for long term plant normal operation (low dose radiation and

low temperature)

3. Commonly accepted definitions of low and medium (action for SDOs)

New NPPs

Status and Path Forward• July:

• Added task group co-chair from industry.• Draft report submitted to Steering Committee for review and

comment.• Task group co-chair facilitating review and update of draft report by

industry.• Late August:

• Finalization of draft final report.• Draft final report to Steering Committee and NESCC.

• September:• Completion of final report.• Publication.