Electrical Cable Aging: Electrical Cable Aging: What does IEEE Std. 1205-2000 What does IEEE Std. 1205-2000

Recommend?Recommend?

Module 5Module 5

Dr. John H. BickelDr. John H. BickelEvergreen Safety & Reliability Technologies, LLCEvergreen Safety & Reliability Technologies, LLC

ObjectivesObjectives Describe origins of IEEE Std.1205-2000Describe origins of IEEE Std.1205-2000 Describe requirements of standard regarding Describe requirements of standard regarding

electrical cableselectrical cables Describe results of recent application in the USDescribe results of recent application in the US

NOTE:NOTE: Standard covers Standard covers allall electrical components. electrical components. Emphasis will be on “Emphasis will be on “difficult to replacedifficult to replace” ”

electrical cables for which justification to use as-electrical cables for which justification to use as-is will be sought.is will be sought.

Origin of IEEE Std 1205-2000Origin of IEEE Std 1205-2000 Many US NPP licenses expiring in next 10 years.Many US NPP licenses expiring in next 10 years. N.R.C. issued License Renewal regulation N.R.C. issued License Renewal regulation

permitting life extension subject to demonstration of permitting life extension subject to demonstration of acceptable safetyacceptable safety

Previous IEEE Std 1205-1993 standard felt to be Previous IEEE Std 1205-1993 standard felt to be too “open ended” in considering “too “open ended” in considering “all possible aging all possible aging mechanisms”. mechanisms”.

Question: “How much is enough?” Question: “How much is enough?” IEEE standard developed as IEEE standard developed as industry – regulator industry – regulator

consensusconsensus on acceptable aging management on acceptable aging management program to demonstrate acceptable safety for program to demonstrate acceptable safety for electrical equipment.electrical equipment.

Basis of New IEEE Std 1205-2000Basis of New IEEE Std 1205-2000 Major NPP systems, components have been Major NPP systems, components have been

continually refurbished or replaced over their continually refurbished or replaced over their lifetimes.lifetimes.

- Steam Generators, RPV head- Steam Generators, RPV head- Turbine rotors- Turbine rotors- Pumps, motors, valves- Pumps, motors, valves- I&C systems, plant computers- I&C systems, plant computers

Original power (and portions of I&C) cable not Original power (and portions of I&C) cable not typically replaced for other reasons.typically replaced for other reasons.

Incorporation of new materials aging dataIncorporation of new materials aging data It is desired to demonstrate safety basis for It is desired to demonstrate safety basis for

acceptability of existing cabling and connectors.acceptability of existing cabling and connectors.

Objectives of IEEE Std 1205-2000Objectives of IEEE Std 1205-2000

Standard deals with Standard deals with all typesall types of electrical of electrical equipment.equipment.

EQ standards (IEEE Std 323-1983) deal with EQ standards (IEEE Std 323-1983) deal with thermal, radiation pre-aging for purposes of thermal, radiation pre-aging for purposes of conducting DBA qualification tests.conducting DBA qualification tests.

IEEE Std 1205-2000 credits that equipment IEEE Std 1205-2000 credits that equipment typically operates for long periods at typically operates for long periods at belowbelow pre-aging temperature, radiation levels.pre-aging temperature, radiation levels.

IEEE Std.1205-2000 Process:IEEE Std.1205-2000 Process:

IEEE Std.1205-2000 Process:IEEE Std.1205-2000 Process:

Aging Assessment ProcessAging Assessment Process

1. Define Evaluation Boundaries1. Define Evaluation Boundaries What is being evaluated?What is being evaluated? What support features are included?What support features are included? What are system interfaces?What are system interfaces? What are system boundaries with interfacing What are system boundaries with interfacing

systems?systems?

Why this is done:Why this is done:To demonstrate at end of job that all systems To demonstrate at end of job that all systems

covered, no duplications, but also no omissionscovered, no duplications, but also no omissions

2. Identify Intended Safety Function2. Identify Intended Safety Function

What safety function does system provide What safety function does system provide for DBA?for DBA?

What other safety functions is system What other safety functions is system credited for?credited for?

Why this is done:Why this is done:Frequently systems are credited for different Frequently systems are credited for different

roles in different scenarios.roles in different scenarios.

3. Identify Plant Locations3. Identify Plant Locations Identify specific rooms or zones of Identify specific rooms or zones of

equipment.equipment.

Why this is done:Why this is done:Routing of support features such as signal Routing of support features such as signal

and power cables needed for determining and power cables needed for determining most limiting rooms or zones.most limiting rooms or zones.

4. Identify Service Conditions4. Identify Service ConditionsWhat are environmental conditions in each What are environmental conditions in each

of the rooms or zones?of the rooms or zones?Temperature, radiation, moisture…..Temperature, radiation, moisture…..Which rooms or zones are most limiting?Which rooms or zones are most limiting?

Why this is done:Why this is done:Identifies locations of likely greatest Identifies locations of likely greatest

stressors for aging-related degradation.stressors for aging-related degradation.

5. Identify Equipment Materials5. Identify Equipment Materials What types of materials for this system are What types of materials for this system are

located in each room or zone?located in each room or zone? Which materials in the system are most limiting?Which materials in the system are most limiting?

Why this is done:Why this is done:A system may have both Power and A system may have both Power and

Instrumentation cables in the same zone. Instrumentation cables in the same zone. Instrumentation cables may be more limiting.Instrumentation cables may be more limiting.

6. Identify and Assess Aging Effects6. Identify and Assess Aging EffectsWhat aging effects are possible for given What aging effects are possible for given

materials and environmental stresses?materials and environmental stresses?Which aging effect is most limiting?Which aging effect is most limiting?

Why this is done:Why this is done:Identification of conditions to be monitored, Identification of conditions to be monitored,

bases for future calculationsbases for future calculations

Thermal and Radiation Thermal and Radiation Aging ModelsAging Models

Thermal and Radiation Aging ModelsThermal and Radiation Aging Models

IEEE Std 1205-2000 starts with standard IEEE Std 1205-2000 starts with standard aging models based Arrhenius type aging aging models based Arrhenius type aging and radiation damage type aging.and radiation damage type aging.

Allows credit for actual operating Allows credit for actual operating experience which may show significantly experience which may show significantly reduced aging rates.reduced aging rates.

Consideration of Operating ExperienceConsideration of Operating Experience

Cabling in areas of highest temperature and Cabling in areas of highest temperature and radiation levels is typically limiting.radiation levels is typically limiting.

Typical EQ efforts conservatively assume, 40 Typical EQ efforts conservatively assume, 40 years at 100% capacity factor.years at 100% capacity factor.

High capacity factors imply higher radiation High capacity factors imply higher radiation doses and exposure to highest temperatures.doses and exposure to highest temperatures.

Actual operation may be less limiting and should Actual operation may be less limiting and should be taken into consideration in projecting residual be taken into consideration in projecting residual cable lifetime.cable lifetime.

Projecting Residual Cable Lifetime Projecting Residual Cable Lifetime Based on Operating ExperienceBased on Operating Experience

Based on actual operating history conservative Based on actual operating history conservative “envelope” on temperature or radiation can be “envelope” on temperature or radiation can be constructed.constructed.

““Envelope” is conservative but also more Envelope” is conservative but also more realistic.realistic.

Construction of Effective Time at Construction of Effective Time at TemperatureTemperature

Desire is to construct Desire is to construct effective temperature effective temperature TTeffeff for residual life for residual life calculations.calculations.

Assume total time Assume total time tttottot

Condition MonitoringCondition Monitoring

Condition MonitoringCondition MonitoringObservation, measurement, trending of Observation, measurement, trending of

condition indicators with respect to critical condition indicators with respect to critical parameter known to cause degradation.parameter known to cause degradation.

Example parameters: Example parameters: cumulative radiation dosecumulative radiation dosecumulative time at effective temperaturecumulative time at effective temperature

Monitor: degradation vs. radiation doseMonitor: degradation vs. radiation doseMonitor: degradation vs. time at Monitor: degradation vs. time at TTeffeff

Acceptable Condition MonitoringAcceptable Condition Monitoring

Acceptable Condition MonitoringAcceptable Condition Monitoring

Some Results from Applying Some Results from Applying IEEE Std 1205-2000IEEE Std 1205-2000

What is Max What is Max TTeffeff for 60 Years ? for 60 Years ?

Calvert Cliffs SER Findings:Calvert Cliffs SER Findings:3.12.3.1 Effects of Aging3.12.3.1 Effects of Aging

““The cable insulation material types include silicone rubber, ethylene The cable insulation material types include silicone rubber, ethylene propylene rubber (EPR), crosslinked polyethylene (XLPE), crosslinked propylene rubber (EPR), crosslinked polyethylene (XLPE), crosslinked polyolefin (XLPO), mineral, Kapton, polyvinyl chloride, Teflon, and polyolefin (XLPO), mineral, Kapton, polyvinyl chloride, Teflon, and other miscellaneous insulation types. other miscellaneous insulation types.

The external environment is air. The applicant identified the applicable The external environment is air. The applicant identified the applicable ARDMs as thermal aging, synergistic thermal and radiative aging, and ARDMs as thermal aging, synergistic thermal and radiative aging, and insulation resistence reduction. insulation resistence reduction.

Although the license renewal rule requires management of aging effects Although the license renewal rule requires management of aging effects and does not require specific identification of ARDMs, the applicant and does not require specific identification of ARDMs, the applicant elected to evaluate specific ARDMs. The applicant considered a elected to evaluate specific ARDMs. The applicant considered a comprehensive list of potential ARDMs in its evaluation. comprehensive list of potential ARDMs in its evaluation.

The staff finds this acceptable because the potential ARDMs of The staff finds this acceptable because the potential ARDMs of thermal/radiative aging, and insulation resistence reduction are thermal/radiative aging, and insulation resistence reduction are considered to be plausible for cables. Accordingly, the staff finds the considered to be plausible for cables. Accordingly, the staff finds the applicant's approach of identifying ARDMs acceptable because aging applicant's approach of identifying ARDMs acceptable because aging effects are results of ARDMs.”effects are results of ARDMs.”

Calvert Cliffs SER Findings:Calvert Cliffs SER Findings:

The operating experience information in the application indicates The operating experience information in the application indicates that the number of cable failures during normal operating conditions that the number of cable failures during normal operating conditions (all voltage classes) that have occurred throughout the industry (all voltage classes) that have occurred throughout the industry have been extremely low. However, thermal aging resulting in have been extremely low. However, thermal aging resulting in embrittlement of insulation is one of the most significant aging embrittlement of insulation is one of the most significant aging mechanisms for low-voltage cable during normal operating mechanisms for low-voltage cable during normal operating conditions.conditions.

Calvert Cliffs SER Findings:Calvert Cliffs SER Findings:3.12.3.2.2 Effects of Synergistic Thermal and Radiative Aging3.12.3.2.2 Effects of Synergistic Thermal and Radiative Aging““Group 3 cables may be subjected to synergistic radiative and thermal Group 3 cables may be subjected to synergistic radiative and thermal

aging when both aging mechanisms are active and at least one may aging when both aging mechanisms are active and at least one may be significant. be significant.

Radiation-induced and thermal-induced degradation in organic Radiation-induced and thermal-induced degradation in organic materials (cable jacket and insulation) produces changes in the materials (cable jacket and insulation) produces changes in the organic material properties, including reduced elongation and organic material properties, including reduced elongation and changes in tensile strength. changes in tensile strength.

Visible indications of radiative/thermal aging may include Visible indications of radiative/thermal aging may include embrittlement, cracking, discoloration, and swelling of the jacket and embrittlement, cracking, discoloration, and swelling of the jacket and insulation. insulation.

To manage the aging effects on Group 3 cables, they will be replaced To manage the aging effects on Group 3 cables, they will be replaced before the extended period of operation if they are found to have before the extended period of operation if they are found to have plausible aging.”plausible aging.”

IEEE Std 1205-2000 Process IEEE Std 1205-2000 Process Aging Management Process has proven to Aging Management Process has proven to

be:be:Orderly Orderly Repeatable Repeatable for both NPP operators making license for both NPP operators making license

extension applications and for NRC in extension applications and for NRC in reviewing and approving.reviewing and approving.

License Renewal Status in US:License Renewal Status in US:License Extensions Approved:License Extensions Approved: Calvert Cliffs, Units 1 and 2 Oconee Nuclear Station, Units 1, 2

and 3 Arkansas Nuclear One, Unit 1    Edwin I. Hatch Nuclear Plant, Units 1

and 2  Turkey Point Nuclear Plant, Units 3

and 4 North Anna, Units 1 and 2, and Surry,

Units 1 and 2 Peach Bottom, Units 2 and 3  St. Lucie, Units 1 and 2  Fort Calhoun Station, Unit 1

License Extensions Pending:License Extensions Pending: McGuire, Units 1 and 2, and Catawba,

Units 1 and 2 - Joint application received June 14, 2001   

H.B. Robinson Nuclear Plant, Unit 2 - Application received June 17, 2002

R.E. Ginna Nuclear Power Plant, Unit 1 - Application received August 1, 2002

V.C. Summer Nuclear Station, Unit 1 - Application received August 6, 2002

Dresden, Units 2 and 3, and Quad Cities, Units 1 and 2 - Application received January 3, 2003. 

Farley, Units 1 and 2 - Application received September 15, 2003.

Arkansas Nuclear One, Unit 2 - Application received October 15, 2003.

D.C. Cook, Units 1 and 2 - Application received November 3, 2003