Effect of aging on the PWR Chemical and Volume Control System
- Brookhaven National Lab., Upton, NY (United States)
The PWR Chemical and Volume Control System (CVCS) is designed to provide both safety and non-safety related functions. During normal plant operation it is used to control reactor coolant chemistry, and letdown and charging flow. In many plants, the charging pumps also provide high pressure injection, emergency boration, and RCP seal injection in emergency situations. This study examines the design, materials, maintenance, operation and actual degradation experiences of the system and main sub-components to assess the potential for age degradation. A detailed review of the Nuclear Plant Reliability Data System (NPRDS) and Licensee Event Report (LER) databases for the 1988--1991 time period, together with a review of industry and NRC experience and research, indicate that age-related degradations and failures have occurred. These failures had significant effects on plant operation, including reactivity excursions, and pressurizer level transients. The majority of these component failures resulted in leakage of reactor coolant outside the containment. A representative plant of each PWR design (W, CE, and B and W) was visited to obtain specific information on system inspection, surveillance, monitoring, and inspection practices. The results of these visits indicate that adequate system maintenance and inspection is being performed. In some instances, the frequencies of inspection were increase in response to repeated failure events. A parametric study was performed to assess the effect of system aging on Core Damage Frequency (CDF). This study showed that as motor-operated valve (MOV) operating failures increased, the contribution of the High Pressure Injection to CDF also increased.
- Research Organization:
- US Nuclear Regulatory Commission (NRC), Washington, DC (United States). Div. of Engineering Technology; Brookhaven National Lab. (BNL), Upton, NY (United States)
- Sponsoring Organization:
- Nuclear Regulatory Commission, Washington, DC (United States)
- DOE Contract Number:
- AC02-76CH00016
- OSTI ID:
- 86970
- Report Number(s):
- NUREG/CR-5954; BNL-NUREG-52410; ON: TI95014434; TRN: 95:017325
- Resource Relation:
- Other Information: PBD: Jun 1995
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
21 NUCLEAR POWER REACTORS AND ASSOCIATED PLANTS
PWR TYPE REACTORS
ECCS
AGING
RELIABILITY
BW STANDARD REACTOR
CE STANDARD REACTOR
WESTINGHOUSE STANDARD REACTOR
REACTOR SAFETY
COOLANTS
WATER CHEMISTRY
INFORMATION SYSTEMS
LOSS OF COOLANT
IN-SERVICE INSPECTION
HIGH PRESSURE COOLANT INJECTION
RECOMMENDATIONS
COMPILED DATA