37600
Najjar, W.S.
The development and application of neutron radiography to study concrete, with emphasis on mierocracking Dissertation Abstracts International, Vol. 48, No. 1, p. 211 (Jul. 1987) Neutron radiography has been successfully developed and used as a testing method for studying microcracking in concrete. The microcracks in a polished concrete specimen are partially impregnated with a contrast agent and subsequently exposed to a neutron flux. The contrast agent is a material with a relatively high neutron attenuation capacity compared to concrete. Gadolinium has been used as the neutron-attenuating contrast agent, which is applied to a polished concrete surface in the form of an aqueous solution of gadolinium nitrate. When a neutron flux is passed through the specimen, neutrons are readily attenuated by the gadolinium in the cracks, which results in a sharp difference in the flux emanating from the cracked and uncracked areas. The resulting radiographs show cracks which are not visible to the unaided eye when directly observing the concrete specimens themselves. Air voids are also identified due to their partial impregnation with the contrast agent. The method is evaluated by comparing it with the more conventional X-ray radiography technique. Neutron radiography appears to be more effective than Xradiography for the identification and study of microcracking in concrete. An analytical model is developed which supports the experimental results. Neutron radiography is successfully applied to study and measure the incidence of microcracking in concrete cylinders as a function of load. 37108
Barton,J.P.; Farny, G.; Walker, J.
Neutron radiography implementation trends l l t h World Conference on Nondestructive Testing. Las Vegas, Nevada (United States), 3-8 Nov. 1985. Vol. 1, pp. 486-488. Taylor Publishing Co., Dallas (1985). Neutron radiography is a small, highly specialized field. Many countries have only one group or one individual working in the field. Their work is often unique. International communication is therefore of much importance. The objective of this paper is to provide a summary analysis of neutron radiography trends world wide, to survey briefly what it can do, and what opportunities are available for implementation.
37004 Ghosh, J.K.; Panakkal, J.P.; Roy, P.R. Quantitative nondestructive evaluation of sealed nuclear fuel elements International Advances in Nondestructive Testing, Vol. 12, pp. 53-70 (1986) Experimental investigation on sealed nuclear fuel elements has resulted in the development of some novel techniques for their quantitative nondestructive evaluation. A simple method for monitoring the internal pressure of welded fuel pins has been evolved. Use of neutron radiography and gamma autoradiography for determining plutonium enrichment and plutonium agglomerates in the fuel pin has been explored. A combination of X-radiography and gamma autoradiography (XGAR) has been evolved for checking the correct loading of fuel pellets and hardware components. Experiments have been carried out to determine the limit of detection of tungsten inclusion in the fuel pin weld configuration. The effect of pre-exposures of films on radiographic sensitivity has also been studied. The use of micro- densitometry for evaluation of weld radiographs has been discussed. The development of a fuel plate scanner for plutonium homogeneity evaluation has been described. The results of thermal nondestructive evaluation of nonbonds in metallic composites simulating defects in plate type fuel elements are also presented in this paper. 36939
Shown Denko Kabushiki Kaisha
Scintillation converter for neutron radiography U.S. Patent No. 4,620,939 (4 Nov. 1986) A scintillation converter for neutron radiography comprising a composition formed of components (A) 100 parts by weight of an olefin rubber made mainly of ethylene and propylene, (B) from 100 to 400 parts by weight of at least one inorganic compound selected from the group consisting of inorganic boron compounds and inorganic lithium compounds, and (C) from 100 to 600 parts by weight of a zinc sulfide- base fluorescent material.
Yamagata, H.; Yoneda, K.; Fujine, S.; Kanda, K.; Katsurayama, K. 36852
Standardization for determining image quality in thermal neutron radiographic testing
37098
Annual Reports of the Research Reactor Institute Kyoto University, Vol. 19, pp. 116-123 (1986) Neutron radiography is relatively recent technology developed mainly for non-destructive testing. One of the applications of this technique is the pre- and pest-irradiation testing of nuclear fuel elements. In any method of testing standard indicators are needed to determine the quality and limitation of the method of testing. Neutron radiography is no exception. At present there are the standard indicators prepared by the American Society for Testing and Materials (ASTM) and the European Atomic Energy Community (EURATOM) for determining image quality in thermal neutron radiographic testing. Although these standard indicators have been widely used. It is thought that they have some limitations for current application of precise measurements. The present paper describes the inadequacies of the current standard indicators and the proposal for solving them,
Evaluation of filter behavior by neutron radiography
36572
Journal of Aerosol Science, Vol. 18, No. 3, pp. 311-320 (Jun. 1987) The personnel at the University of Virginia Reactor Facility and the Philip Morris Research Center have jointly developed a real-time neutron radiography system. The neutron radiography system was used to observe the deposition of a neutron absorbing aerosol in a filter. An aqueous solution of gadolinium chloride was nebulized and the resulting aerosol was dried and charge neutralized. The filters used for these experiments were standard cellulose acetate cigarette filters. Neutron radiography is shown to be an effective nondestructive method for the evaluation of filter behavior. The technique is capable of real-time observation of the aerosol deposition. In addition, the deposition patterns can be analyzed quantitatively as a function of both time and penetration distance into the filter from the same experimental run.
Radiography experiments at Argonne National Laboratory
37099
Balasko, M.; Svab, E.; Cser, L.
Simultaneous dynamic neutron and gamma radiography N D T International, Vol. 20, No. 3, pp. 157-160 (3 Jun. 1987) Equipment for dynamic neutron and gamma radiography has been developed at the 4.6 MW research reactor in Budapest, using thermal neutrons and gamma radiation obtained from the reactor. Radiography images are detected by scintillator screens and by low-light-level TV cameras, providing the possibility of visualizing medium-speed movements inside the investigated objects. The images are displayed on monitors and stored on video recorders. Some applications for nondestructive investigations are given.
Brenizer,J.S.; Sulcoski, M.F.; Tobin, K. W. Jr.;Jenkins, R.W. Jr. R.W.; McRae, D.D.
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250
Richards, W.J.; Larson, H.A.
Nuclear Technology, Vol. 76, No. 3, pp. 408-419 (Mar. 1987) Several neutron radiography experiments were done at the Neutron Radiography Reactor facility, Argonne national Laboratory, Idaho Falls, Idaho. Square samples of cadmium were exposed to collimated neutrons (L/D= 185 and 300) to determine the width of the squares. Two methods of analysis, the arctangent fitting technique and the differential smoothing technique, were applied to data produced by microdensitometer measurements of several types of film. The results were compared for accuracy and precision with a carefully calibrated measurement of the samples. From the mathematical analysis a resolution parameter is obtained that might serve as a facility calibration parameter.
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NDT International August 1989