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Aging and service wear of air-operated valves used in safety-related systems at nuclear power plants

Description: Air-operated valves (AOVs) are used in a variety of safety-related applications at nuclear power plants. They are often used where rapid stroke times are required or precise control of the valve obturator is required. They can be designed to operate automatically upon loss of power, which is often desirable when selecting components for response to design basis conditions. The purpose of this report is to examine the reported failures of AOVs and determine whether there are identifiable trends … more
Date: May 1, 1995
Creator: Cox, D. F.; McElhaney, K. L. & Staunton, R. H.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

Development of wear-resistant coatings for cobalt-base alloys

Description: The level of nuclear plant radiation exposure due to activated cobalt wear debris could potentially be reduced by covering the cobalt-base materials with a wear resistant coating. Laboratory pin-on-disc and rolling contact wear tests were used to evaluate the wear performance of several coatings. Based on the results of these tests, multilayer Cr-nitride coatings and ion nitriding are the most promising approaches.
Date: October 22, 1999
Creator: Cockeram, B.V.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

Development of wear-resistant coatings for cobalt-base alloys

Description: The costs and hazards resulting from nuclear plant radiation exposure with activated cobalt wear debris could potentially be reduced by covering the cobalt-base materials with a wear resistant coating. However, the hardnesses of many cobalt-base wear alloys are significantly lower than conventional PVD hard coatings, and mechanical support of the hard coating is a concern. Four approaches have been taken to minimize the hardness differences between the substrate and PVD hard coating: (1) use a … more
Date: March 1, 1999
Creator: Cockeram, B.V.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

Axial piston pump wear plates, Delta-Q Corporation

Description: The Savannah River Technical Center visually examined several axial piston pump wear plates from Delta-Q Corporation in an effort to determine the cause of the scratches. The investigation found the material and hardness to be approximately consistent with vendor specifications. The visual examination revealed gouges and tears on plates 1 - 4, silicon and aluminum contamination on plates 2 & 3 and a heavy inclusion content in the base metal. The scratches were most likely attributable to either… more
Date: April 6, 1994
Creator: Campbell, J. K. & White, M. B.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

Detection of pump degradation

Description: There are a variety of stressors that can affect the operation of centrifugal pumps. Although these general stressors are active in essentially all centrifugal pumps, the stressor level and the extent of wear and degradation can vary greatly. Parameters that affect the extent of stressor activity are manifold. In order to assure the long-term operational readiness of a pump, it is important to both understand the nature and magnitude of the specific degradation mechanisms and to monitor the per… more
Date: December 31, 1994
Creator: Casada, D.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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High rate sputter deposition of wear resistant tantalum coatings

Description: The refractory nature and high ductility of body centered cubic (bcc) phase tantalum makes it a suitable material for corrosion- and wear-resistant coatings on surfaces which are subjected to high stresses and harsh chemical and erosive environments. Sputter deposition can produce thick tantalum films but is prone to forming the brittle tetragonal beta phase of this material. Efforts aimed at forming thick bcc phase tantalum coatings in both flat plate and cylindrical geometries by high-rate tr… more
Date: November 1, 1991
Creator: Matson, D. W.; Merz, M. D. & McClanahan, E. D.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

Aging and service wear of spring-loaded pressure relief valves used in safety-related systems at nuclear power plants

Description: Spring-loaded pressure relief valves (PRVS) are used in some safety-related applications at nuclear power plants. In general, they are used in systems where, during accidents, pressures may rise to levels where pressure safety relief is required for protection of personnel, system piping, and components. This report documents a study of PRV aging and considers the severity and causes of service wear and how it is discovered and corrected in various systems, valve sizes, etc. Provided in this re… more
Date: March 1, 1995
Creator: Staunton, R.H. & Cox, D.F.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

Laboratory galling tests of several commercial cobalt-free weld hardfacing alloys

Description: Since the mechanical properties of most wear materials are generally insufficient for structural applications, hardfacing alloys have been traditionally weld deposited to provide a wear resistance surface for a base material. An important attribute of a hardfacing alloy that is subjected to high load sliding contact is the resistance to adhesive (galling) damage. Although Co-base hardfacing alloys generally possess excellent galling wear resistance, there is interest in developing cobalt-free r… more
Date: April 1, 1997
Creator: Cockeram, B. V.; Buck, R. F. & Wilson, W. L.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

Aging of Electric Motors in Nuclear Power Plants

Description: Motor degradation due to aging and service wear decreases reliability and increases the potential for failure during nuclear plant accident and post accident conditions. The impact of motor failures on plant safety is an important concern among the nuclear utilities and the government agency regulating this industry. Economic impacts, relating to plant availability and safety, as well as corrective maintenance, have prompted utilities to improve their maintenance programs to mitigate such aging… more
Date: June 1, 1987
Creator: Subudhi, Mano & Taylor, John H.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Engineering evaluation of the General Motors (GM) diesel rating and capabilities

Description: K-Reactor`s number one GM diesel (GM-lK) suffered recurrent, premature piston pin bushing failures between July 1990 and January 1991. These failures raised a concern that the engine`s original design capabilities were being exceeded. Were we asking old engines to do too much by powering 1200 kw (continuous) rated electrical generators? Was excessive wear of the piston pin bushings a result of having exceeded the engine`s capabilities (overload), or were the recent failures a direct result of p… more
Date: April 1, 1992
Creator: Gross, R. E.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

Check valves aging assessment

Description: In support of the NRC Nuclear Plant Aging Research (NPAR) program, the Oak Ridge National Laboratory (ORNL) has carried out an assessment of several check value diagnostic monitoring methods, in particular, those based on measurements of acoustic emission, ultrasonics, and magnetic flux. The evaluations have focussed on the capabilities of each method to provide information useful in determining check valve aging and service wear effects, check valve failures, and undesirable operating modes. T… more
Date: January 1, 1991
Creator: Haynes, H. D.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

Effects of aging and service wear on main steam isolation valves and valve operators

Description: In recent years main steam isolation valve (MSIV operating problems have resulted in significant operational transients (e.g., spurious reactor trips, steam generator dry out, excessive valve seat leakage), increased cost, and decreased plant availability. A key ingredient to an engineering-oriented reliability improvement effort is a thorough understanding of relevant historical experience. A detailed review of historical failure data available through the Institute of Nuclear Power Operation`… more
Date: March 1996
Creator: Clark, R. L.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

Status of motor operated valves aging assessment

Description: Motor operated valves (MOVs) have a long history of operational problems in nuclear power plants. Resolution of MOV problems in the past has tended to focus on symptoms rather than root cause. Although there has been more attention focused recently on identifying root causes, problems with valve operational readiness resulting from aging and service wear still persist. In addition, weaknesses in the currently used design equations for sizing of MOVs, identified in tests carried out by industry … more
Date: January 1, 1989
Creator: Eissenberg, D.M.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

Reactor safety research section probability of heat exchanger leaks

Description: Three heat exchangers (HXs) were changed out after the December 1991 leak of Process Water to the Savannah River. This leaves 6 of the original 304 stainless steel heat exchangers which will remain in K-Reactor for restart. This report discusses SRS site specific data which were used to estimate the probability of a leak within a one-year period as a function of leak rate and root cause in these six heat exchangers in conjunction with six new heat exchangers presently in service in K-Reactor. B… more
Date: February 1, 1992
Creator: Cramer, D. S.; Shine, E. P. & Copeland, W. J.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

Aging and service wear of auxiliary feedwater pumps for PWR nuclear power plants

Description: This paper describes investigations on auxiliary feedwater pumps being done under the Nuclear Plant Aging Research (NPAR) Program. Objectives of these studies are: to identify and evaluate practical, cost-effective methods for detecting, monitoring, and assessing the severity of time-dependent degradation (aging and service wear); recommend inspection and maintenance practices; establish acceptance criteria; and help facilitate use of the results. Emphasis is given to identifying and assessing … more
Date: January 1, 1989
Creator: Greenstreet, W. L.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

Aging assessment of the boiling-water reactor (BWR) standby liquid control system. Phase 1

Description: Pacific Northwest Laboratory conducted a Phase I aging assessment of the standby liquid control (SLC) system used in boiling-water reactors. The study was based on detailed reviews of SLC system component and operating experience information obtained from the Nuclear Plant Reliability Database System, the Nuclear Document System, Licensee Event Reports, and other databases. Sources dealing with sodium pentaborate, borates, boric acid, and the effects of environment and corrosion in the SLC syst… more
Date: October 1, 1992
Creator: Orton, R. D.; Johnson, A. B.; Buckley, G. D. & Larson, L. L.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

Procedures for evaluating technical specifications

Description: The Procedures for Evaluating Technical Specifications (PETS) Program being conducted by Brookhaven National Laboratory for the Office of Research, US Nuclear Regulatory Commission (NRC), is developing various risk-based approaches for modifying Technical Specifications (TS). This paper highlights the various risk-based issues being addressed by the program and presents examples that exemplify the use of PRA models for modifying TS, primarily elements of the Limiting Condition of Operation (LCO… more
Date: January 1, 1987
Creator: Boccio, J. L.; Robinson, R. C.; Samanta, P. K. & Vesely, W. E.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

High rate sputter deposition of wear resistant tantalum coatings

Description: The refractory nature and high ductility of body centered cubic (bcc) phase tantalum makes it a suitable material for corrosion- and wear-resistant coatings on surfaces which are subjected to high stresses and harsh chemical and erosive environments. Sputter deposition can produce thick tantalum films but is prone to forming the brittle tetragonal beta phase of this material. Efforts aimed at forming thick bcc phase tantalum coatings in both flat plate and cylindrical geometries by high-rate tr… more
Date: November 1, 1991
Creator: Matson, D. W.; Merz, M. D. & McClanahan, E. D.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

Life testing of a low voltage air circuit breaker

Description: ADS-416 low voltage air circuit breaker manufacture by Westinghouse was mechanically cycled to identify age-related degradation in various breaker subcomponents, in particular, the power-operating mechanism. This accelerated aging test was performed on one breaker unit for over 36,000 cycles. Three separate pole shafts, one with a 60 degree weld, one with a 120 degree weld and one with a 180 degree weld in the third pole lever were used to characterize the cracking in these welds. In addition, … more
Date: January 1, 1991
Creator: Subudhi, M.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

Engineering evaluation of the General Motors (GM) diesel rating and capabilities

Description: K-Reactor's number one GM diesel (GM-lK) suffered recurrent, premature piston pin bushing failures between July 1990 and January 1991. These failures raised a concern that the engine's original design capabilities were being exceeded. Were we asking old engines to do too much by powering 1200 kw (continuous) rated electrical generators Was excessive wear of the piston pin bushings a result of having exceeded the engine's capabilities (overload), or were the recent failures a direct result of po… more
Date: April 1, 1992
Creator: Gross, R. E.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

Aging assessment of reactor instrumentation and protection system components. Aging-related operating experiences

Description: A study of the aging-related operating experiences throughout a five-year period (1984--1988) of six generic instrumentation modules (indicators, sensors, controllers, transmitters, annunciators, and recorders) was performed as a part of the Nuclear Plant Aging Research Program. The effects of aging from operational and environmental stressors were characterized from results depicted in Licensee Event Reports (LERs). The data are graphically displayed as frequency of events per plant year for o… more
Date: July 1, 1992
Creator: Gehl, A. C. & Hagen, E. W.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

Phase I Aging Assessment of the Boiling-Water Reactor (BWR) Standby Liquid Control System

Description: Pacific Northwest Laboratory conducted a Phase I aging assessment of the standby liquid control (SLC) system used in boiling-water reactors. The study was based on detailed reviews of SLC system component and operating experience information obtained from the Nuclear Plant Reliability Database System, the Nuclear Document System, Licensee Event Reports, and other databases. Sources dealing with sodium pentaborate, borates, boric acid, and the effects of environment and corrosion in the SLC syst… more
Date: October 1, 1992
Creator: Orton, R. D.; Johnson, A. B.; Buckley, G. D. & Larson, L. L.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

Aging assessment of BWR control rod drive systems

Description: This study examines the aging phenomena associated with boiling water reactor (BWR) control rod drive mechanisms (CRDMs) and assess the merits of various methods of managing this aging. Information for this study was acquired from (1) the results of a special CRDM aging questionnaire distributed to each US BWR utility, (2) a first-of-its-kind workshop held to discuss CRDM aging and maintenance concerns, (3) an analysis of Nuclear Plant Reliability Data System (NPRDS) failure cases attributed to… more
Date: January 1, 1991
Creator: Greene, R.H.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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