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Title: METHODOLOGY FOR EXAMINING SYSTEM AGING DUE TO INTERACTIONS BETWEEN CHEMICALLY INCOMPATIBLE MATERIALS

We start with a stored and unused population of fielded engineered units that are composed of chemically incompatible materials. The units age primarily through heterogeneous chemical reactions between the materials resulting in possible degradation in performance. The engineered units are unused in storage, but may be called into actual service at any time. We sample several units from the population per year and perform a number of non-destructive evaluation (NDE) techniques, such as radiography, low-frequency vibration analysis, and ultrasonic imaging on the selected units. From those units, some are selected for destructive testing (D-test) involving disassembly and testing of internal parts and components. Chemical analyses, mechanical properties measurements and other tests are performed. All of the above steps provide information that is used in the system simulation mathematical model. The system simulation model incorporates chemical reactions and gas-solid transport processes, along with changes in both the surface and bulk properties of the solids. Model results are used to suggest improvements in NDE analyses of the units and improvements in component and material analyses. Model results give trending indications of individual component and overall system changes over time, plus some understanding of the mechanisms involved which allow science-based predictions of themore » aged state of the units in future times. The NDE, D-test, and model results can also be used to assess statistically the reliability and performance of the overall aging population of units.« less
Authors:
;
Publication Date:
OSTI Identifier:
773892
Report Number(s):
LA-UR-99-3453
TRN: AH200123%%54
DOE Contract Number:
W-7405-ENG-36
Resource Type:
Conference
Resource Relation:
Conference: Conference title not supplied, Conference location not supplied, Conference dates not supplied; Other Information: PBD: 1 Apr 1999
Research Org:
Los Alamos National Lab., NM (US)
Sponsoring Org:
US Department of Energy (US)
Country of Publication:
United States
Language:
English
Subject:
42 ENGINEERING; 36 MATERIALS SCIENCE; AGING; CHEMICAL REACTIONS; DESTRUCTIVE TESTING; MATHEMATICAL MODELS; MECHANICAL PROPERTIES; MATERIALS; COMPATIBILITY; SERVICE LIFE