An aging assessment of relays and circuit breakers and system interactions

Technical Report · Mon Jun 01 04:00:00 EDT 1987

OSTI ID:6096829

Toman, G J; Bacanskas, V P; Shook, T A; Ladlow, C C

This report provides an assessment of the aging of circuit breakers and relays which are vital components of the nuclear power plant electrical safety system, and was conducted under the auspices of the NRC Nuclear Aging Research (NPAR) Program. The study included protective, control, and logic relays, and molded-case and metal-clad switchgear circuit breakers. The relay failures were attributable to coil deterioration, changes in dimensions of critical organic components, and changes in characteristics of timing diaphragms from thermal deterioriation. Some of the failure modes will prevent fail-safe operation. The electrical control and mechanical portions of metal-clad switchgear were found to be more failure prone than the main contacts and arc extinguishing systems. Circuit breakers and relays in a PWR safety injection system were evaluated with respect to the aging induced by system operation. The effect of circuit breaker and relay deterioration on the ability of the system to perform its safety functions was also evaluated.

• Research Organization: Brookhaven National Lab., Upton, NY (USA); Nuclear Regulatory Commission, Washington, DC (USA). Office of Nuclear Regulatory Research
• DOE Contract Number: AC02-76CH00016
• OSTI ID: 6096829
• Report Number(s): NUREG/CR-4715; BNL-NUREG-52017; ON: DE88000884
• Country of Publication: United States
• Language: English

Related Subjects

22 GENERAL STUDIES OF NUCLEAR REACTORS
220400 -- Nuclear Reactor Technology-- Control Systems
220900* -- Nuclear Reactor Technology-- Reactor Safety
AGING
CIRCUIT BREAKERS
DATA ANALYSIS
ELECTRICAL EQUIPMENT
ENGINEERED SAFETY SYSTEMS
EQUIPMENT
EQUIPMENT PROTECTION DEVICES
FAILURES
NUCLEAR FACILITIES
NUCLEAR POWER PLANTS
POWER PLANTS
REACTOR COMPONENTS
REACTOR SAFETY
RELAYS
SAFETY
STRESSES
THERMAL POWER PLANTS
WEAR