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ORNL high-temperature structural design methods development program

Description: From joint meeting of the American Nuclear Society and the Atomic Industrial Forum and Nuclear Energy Exhibition; San Francisco, California, USA (11 Nov 1973). A program to develop and evaluate high-temperature structural design methods and criteria for use in the design of Liquid Metal Fast Breeder Reactor (LMFBR) system components is described. Inelastic behaviors of these components under timevarying temperature and load conditions are of primary interest. Time-varying temperature conditions are especially important because, in addition to producing significant changes in material properties, large thermal strains can be induced due to the good heat transfer characteristics of the sodium coolant. The program addresses three major aspects; these are (1) deformation behavior, (2) failure associated with creep rupture, brittle fracture, fatigue, creep-fatigue interactions, and crack propagation, and (3) the establishment of appropriate design criteria. Included in the first category are studies of materials behavior, the development of mathematical analogs, or constitutive equations, to describe the essential features of this behavior, and the development and assessment of structural analysis methods. The materials of interest are types 304 and 316 stainless steel, and temperatures of interest range to 1200 deg F. (auth)
Date: January 1, 1973
Creator: Greenstreet, W.L.
Partner: UNT Libraries Government Documents Department

Summary and accomplishments of the ORNL program for nuclear piping design criteria

Description: The ORNL Piping Program was defined and established to develop basic information on the structure behavior of nuclear power plant piping components and to prepare this information in forms suitable for use in design codes and standards. Charts are presented showing the percentage completion of the various program tasks. (DG)
Date: November 1, 1975
Creator: Greenstreet, W.L.
Partner: UNT Libraries Government Documents Department

Experimental study of plastic responses of pipe elbows

Description: Load-deflection responses were determined experimentally for sixteen 152.4-mm (6-in.) (nominal) commercial carbon steel pipe elbows and four 152.4-mm (6-in.) stainless steel elbows. Each specimen was loaded with an external force of sufficient magnitude to produce predominantly plastic response. The influences of bend radius and wall thickness were studied, as well as the effect of internal prssure on load-deflection behavior. Comparisons of results from stainless steel and from carbon steel elbows indicate differences in responses attributable to material differences. The results were interpreted in terms of limit analysis concepts, and collapse loads were determined. Trends given by the collapse loads are identified and discussed.
Date: January 20, 1978
Creator: Greenstreet, W.L.
Partner: UNT Libraries Government Documents Department

Aging assessment of auxiliary feedwater pumps

Description: ORNL is conducting aging assessments of auxiliary feedwater pumps to provide recommendations for monitoring and assessing the severity of time-dependent degradation as well as to recommend maintenance and replacement practices. Cornerstones of these activities are the identification of failure modes and causes and ranking of causes. Failure modes and causes of interest are those due to aging and service wear. Design details, functional requirements, and operating experience data were used to identify failure modes and causes and to rank the latter. Based on this input, potentially useful inspection, surveillance, and condition monitoring methods that are currently available for use or in the developmental stage were examined and recommendations made. The methods selected are listed and discussed in terms of use and information to be obtained. Relationships between inspection, surveillance, and monitoring and maintenance practices entered prominently into maintenance recommendations. These recommendations, therefore, embrace predictive as well as corrective and preventative maintenance practices. The recommendations are described, inspection details are discussed, and periodic inspection and maintenance interval guidelines are given. Surveillance testing at low-flow conditions is also discussed. It is shown that this type of testing can lead to accelerated aging.
Date: January 1, 1987
Creator: Greenstreet, W.L.
Partner: UNT Libraries Government Documents Department

Low-flow operation and testing of pumps in nuclear plants

Description: Low-flow operation of centrifugal pumps introduces hydraulic instability and other factors that can cause damage to these machines. The resulting degradation has been studied and recorded for pumps in electric power plants. The objectives of this paper are to (1) describe the damage-producing phenomena, including their sources and consequences; (2) relate these observations to expectations for damage caused by low-flow operation of pumps in nuclear power plants; and (3) assess the utility of low-flow testing. Hydraulic behavior during low-flow operation is reviewed for a typical centrifugal pump stage, and the damage-producing mechanisms are described. Pump monitoring practices, in conjunction with pump performance characteristics, are considered; experience data are reviewed; and the effectiveness of low-flow surveillance monitoring is examined. Degradation caused by low-flow operation is shown to be an important factor, and low-flow surveillance testing is shown to be inadequate. 18 refs., 5 figs., 4 tabs.
Date: January 1, 1989
Creator: Greenstreet, W.L.
Partner: UNT Libraries Government Documents Department

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 methods for detecting failure in the incipient stage and to developing degradation trends to allow timely maintenance, repair or replacement actions. 3 refs.
Date: January 1, 1989
Creator: Greenstreet, W.L.
Partner: UNT Libraries Government Documents Department