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Quantitative nondestructive evaluation of sealed nuclear fuel elements
very low content of gamma rays; in the other, the NR beam contains a greatly increased fraction of very highly collimated gamma rays. For some NR objects, the compound beam compared to an essentially pure neutron beam offers particular advantages for radiographic imaging. 37836
Moghadam, K.K.; Tabatabaeian, Z.; Mirhabibi, N.
Neutron radiography facility for AEOi nuclear research center N e u t r o n R a d i o g r a p h y , P r o c e e d i n g s of the S e c o n d W o r l d C o n f e r e n c e , Paris ( F r a n c e ) , 16-20 Jun. 1986. pp. 25-32. D. R e i d e l P u b l i s h i n g Company Recently a Neutron Radiography System has been designed, constructed and installed at the research reactor of Tehran Nuclear Research Center (TNRC). The 6 inch through tube was chosen because of its low gamma intensity. A collimator was made of two parts, iron and lead, which were covered thoroughly with cadmium. Cylindrical slabs of bismuth and graphite of calculated lengths were made to reduce gamma intensity and to thermalize fast neutrons respectively. The collimated thermal flux is uniform in direction and intensity, and at the reactor wall and thermal power of 1 MW, the beam has following characteristics: Average thermal flux of 6.1"104 n/cm ~ sec, cadmium ratio (thermal per total activity) of 98% and neutron gamma ratio of 5"105 n/cm2mR. 37509
Holt, R.S.; Cooper, M.J.
The uses of scattered beam X-rays NDT-86. P r o c e e d i n g s of the 21st A n n u a l British C o n f e r e n c e on N o n d e s t r u c t i v e Testing, N e w c a s t l e - u p o n - T y n e ( U n i t e d K i n g d o m ) , 16-18 Sep. 1986. pp. 645-656. E d i t e d by J.M. F a r l e y a n d P . D . H a n s t e a d . E n g i n e e r i n g M a t e r i a l s A d v i s o r y Services Ltd. (1987) The scattering of low and high energy X-ray and gamma-ray beams is becoming an important non-destructive examination probe of industrial materials. Both the elastic and inelastic (Compton) scattering intensities arc sensitive to the (electron) density of the material and have been used in a variety of ways to characterise defective structures both near the surface and deeply embedded within an object. Some of these dcnsitometric and imaging techniques arc described here together with illustrative examples highlighting the unique qualities of scatter NDE. 37436
Sauerweink
Non-destructive test equipment using X or gamma ray images - uses a mask made by exposing negative to fluorescent screen image to darken over-bright image areas
related phases. Initially, results of previously obtained measurements, using a low energy source and a low density material, were reanalyzed to determine the applicability, limitations and preferred geometrical configurations. These analyses provided valuable information for the highly successful high density and high energy source experimental program. The following voids and cracks were clearly detected: lmm central void in a 50 mm diameter aluminum rod, annular void of 2.5 mm in a 25 mm diameter iron rod, three equally spaced 3 mm holes in a 33 mm diameter aluminum rod, and mid-radius circumferential barrel-shape cracks as small as 1 mm. Submillimeter detection appears feasible but requires improved experimental facilities which are currently under development. 37099
Balasko, M.; Svab, E.; Cser, L.
Simultaneous dynamic neutron and gamma radiography N D T I n t e r n a t i o n a l , 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. 37004
Ghosh, J.K.; Panakkal, J.P.; Roy, P.R.
Quantitative nondestructive evaluation of sealed nuclear fuel elements I n t e r n a t i o n a l A d v a n c e s in N o n d e s t r u c t i v e Testing, Vol. 12, pp. 53-70 (1986) Experimental investigation on scaled 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.
E u r o p e a n P a t e n t No. 205,825 (30 Dec. 1986)
Mossop, J.R.; Kerr, S.A.; Bradley, D.A.; Chong, C.S.; Ghose, A.M.
36603 37390
Gusev, E.A.; Potapov, V.M.
Calculation of X- and gamma-radiation fields in absorbers of complex geometry
The use of coherent gamma-ray scattering for the characterisation of materials
Soviet J o u r n a l of N o n d e s t r u c t i v e Testing, Vol. 22, No. 11, pp. 756-759 (Jul. 1987) The characteristics of solving the problem of radiative transfer through barriers with a complex geometric shape as applied to the problem of nondestructive radiation inspection are examined. A method of calculating photon radiation fields is described which is based on a successive transition from a homogeneous plane-parallel absorber to a medium with a complex geometry by gradually changing the shape of the absorber and subsequent evaluation of the effect of these changes on the radiation field by means of the theory of small perturbations.
N u c l e a r I n s t r u m e n t s a n d M e t h o d s in Physics R e s e a r c h , Vol. A255, No. 1/2, pp. 419-422 (15 Mar. 1987) Gamma-ray scattering techniques are well established for the characterisation of biomedical and industrial materials. To date all have relied either on measurements of Compton scattering or the ratio of coherent to Compton scattering intensities. This paper investigates the use of coherent scattering alone and discusses the choice of scattering angle for optimum sensitivity. Experimental results are presented for the coherent scattering of 60 keV gamma-rays by potassium orthophosphate (K/suh2/HPO/sub4/) solutions with densities ranging from 1.0-t.7 g cm/sup-3/. The results demonstrate an improvement in sensitivity by a factor of 1.9, when compared with the coherent/Compton ratio method, for noninvasiv¢ density measurements on low-Z materials.
37385
Deleuze, M.P.
Inspection of high-density materials by means of X- and gammaradiography and X- and gamma-radioscopy M a t e r i a l s E v a l u a t i o n , Vol. 45, No. 8, pp. 939-942 ( A u g . 1987) This paper presents test conducted by the Commissariat a I'Energie Atomique, Paris, France, on uranium testpieces for purposes of evaluating comparatively the capabilities and limitations of x-and gamma-radiography and x- and gamma-radioscopy. The points of comparison are the exposure and inspection times, the radiographic contrast, the defect detection sensitivity, and the choice of radiation source. These tests made it possible to determine the limiting thicknesses of uranium that can be inspected by these two techniques. Accordingly, we decided to replace our existing iridium-192 gammaradiography with 420 kV x-radioscopy and -radiography. 37126
Holt, R.S.; Cooper, M.J.
Gamma-ray scattering NDE N D T I n t e r n a t i o n a l , Vol. 20, No. 3, pp. 161-165 (3 Jun. 1987) Compton scattering of gamma radiation offers an alternative approach for the nondestructive examination of defects in metals and alloys. A prototype scanner based on a 137-Cs isotope has been constructed to evaluate.the inherent sensitivity of the method in characterizing structural defects in bulk materials. The initial results show that voids with linear dimensions of the order of half of the beam width can be detected and located within a small fraction of the beam size. 37125
Anghaie, S.; Diaz, N.J.
Nondestructive detection and sizing of flaws by differential gamma scattering spectrum techniques I S A T r a n s a c t i o n s , Vol. 26, No. 2, pp. 13-33 (1987) This paper describes the results of an experimental program designed to examine the capabilities of the differential gamma scattering technique for high resolution nondestructive testings. The experimental program consisted of two
N D T & E International June 1991
36602
Henderson, I.A.; McGhee, J.
Modelling gamma-source backscatter density gauges I E E P r o c e e d i n g s , Vol. 133, No. 9, pp. 611-617 ( D e c . 1986) Gamma-source backscatter gauges arc used to obtain a nonintrusive measurement of the density of rocks and soils from the surface. The static and moving-source versions of these instruments, which have been developed previously, allow an in situ investigation of a bulk sample of a material. Changes in gauge design and factors affecting the homogeneity of the material alter the backscatter characteristics. A model, which accurately represents the detector in its working environment, is developed for all gamma-source backscatter density gauges. Whereas previous models emulate the absorption and scattering processes, the presented model allows a direct comparison of the maxima and shape, or bandwidth, of the experimental and theoretical predicted results. The model makes this comparison possible through the formulation of characteristic differential equations together with accurate calculations of both the maxima and normalised bandwidth of the characteristics for both versions of these backscatter density gauges. This allows an accurate comparison of design parameters by different routes and could form a basis for new backscatter gauge designs. Fresh applications involving surface measurements of in situ bulk materials could also result from this model. 36582
Schotanus, P.; Eijk, C. W.E.; Hollander, R. W.; Pijpelink, J.
Development study of a new gamma camera I E E E T r a n s a c t i o n s on N u c l e a r Science, Vol. NS-34, No. 1, pp. 272-276 (Feb. 1987) Energy, time and position resolution have been studied, for 511 key annihilation radiation detected in a 15 cm diameter, 8 mm thick BaF/sub2/ crystal coupled to a multiwire proportional chamber filled with TMAE. Properties of other UV scintillators have also been studied.
1 57
Moghadam, K.K.; Tabatabaeian, Z.; Mirhabibi, N.
Neutron radiography facility for AEOi nuclear research center N e u t r o n R a d i o g r a p h y , P r o c e e d i n g s of the S e c o n d W o r l d C o n f e r e n c e , Paris ( F r a n c e ) , 16-20 Jun. 1986. pp. 25-32. D. R e i d e l P u b l i s h i n g Company Recently a Neutron Radiography System has been designed, constructed and installed at the research reactor of Tehran Nuclear Research Center (TNRC). The 6 inch through tube was chosen because of its low gamma intensity. A collimator was made of two parts, iron and lead, which were covered thoroughly with cadmium. Cylindrical slabs of bismuth and graphite of calculated lengths were made to reduce gamma intensity and to thermalize fast neutrons respectively. The collimated thermal flux is uniform in direction and intensity, and at the reactor wall and thermal power of 1 MW, the beam has following characteristics: Average thermal flux of 6.1"104 n/cm ~ sec, cadmium ratio (thermal per total activity) of 98% and neutron gamma ratio of 5"105 n/cm2mR. 37509
Holt, R.S.; Cooper, M.J.
The uses of scattered beam X-rays NDT-86. P r o c e e d i n g s of the 21st A n n u a l British C o n f e r e n c e on N o n d e s t r u c t i v e Testing, N e w c a s t l e - u p o n - T y n e ( U n i t e d K i n g d o m ) , 16-18 Sep. 1986. pp. 645-656. E d i t e d by J.M. F a r l e y a n d P . D . H a n s t e a d . E n g i n e e r i n g M a t e r i a l s A d v i s o r y Services Ltd. (1987) The scattering of low and high energy X-ray and gamma-ray beams is becoming an important non-destructive examination probe of industrial materials. Both the elastic and inelastic (Compton) scattering intensities arc sensitive to the (electron) density of the material and have been used in a variety of ways to characterise defective structures both near the surface and deeply embedded within an object. Some of these dcnsitometric and imaging techniques arc described here together with illustrative examples highlighting the unique qualities of scatter NDE. 37436
Sauerweink
Non-destructive test equipment using X or gamma ray images - uses a mask made by exposing negative to fluorescent screen image to darken over-bright image areas
related phases. Initially, results of previously obtained measurements, using a low energy source and a low density material, were reanalyzed to determine the applicability, limitations and preferred geometrical configurations. These analyses provided valuable information for the highly successful high density and high energy source experimental program. The following voids and cracks were clearly detected: lmm central void in a 50 mm diameter aluminum rod, annular void of 2.5 mm in a 25 mm diameter iron rod, three equally spaced 3 mm holes in a 33 mm diameter aluminum rod, and mid-radius circumferential barrel-shape cracks as small as 1 mm. Submillimeter detection appears feasible but requires improved experimental facilities which are currently under development. 37099
Balasko, M.; Svab, E.; Cser, L.
Simultaneous dynamic neutron and gamma radiography N D T I n t e r n a t i o n a l , 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. 37004
Ghosh, J.K.; Panakkal, J.P.; Roy, P.R.
Quantitative nondestructive evaluation of sealed nuclear fuel elements I n t e r n a t i o n a l A d v a n c e s in N o n d e s t r u c t i v e Testing, Vol. 12, pp. 53-70 (1986) Experimental investigation on scaled 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.
E u r o p e a n P a t e n t No. 205,825 (30 Dec. 1986)
Mossop, J.R.; Kerr, S.A.; Bradley, D.A.; Chong, C.S.; Ghose, A.M.
36603 37390
Gusev, E.A.; Potapov, V.M.
Calculation of X- and gamma-radiation fields in absorbers of complex geometry
The use of coherent gamma-ray scattering for the characterisation of materials
Soviet J o u r n a l of N o n d e s t r u c t i v e Testing, Vol. 22, No. 11, pp. 756-759 (Jul. 1987) The characteristics of solving the problem of radiative transfer through barriers with a complex geometric shape as applied to the problem of nondestructive radiation inspection are examined. A method of calculating photon radiation fields is described which is based on a successive transition from a homogeneous plane-parallel absorber to a medium with a complex geometry by gradually changing the shape of the absorber and subsequent evaluation of the effect of these changes on the radiation field by means of the theory of small perturbations.
N u c l e a r I n s t r u m e n t s a n d M e t h o d s in Physics R e s e a r c h , Vol. A255, No. 1/2, pp. 419-422 (15 Mar. 1987) Gamma-ray scattering techniques are well established for the characterisation of biomedical and industrial materials. To date all have relied either on measurements of Compton scattering or the ratio of coherent to Compton scattering intensities. This paper investigates the use of coherent scattering alone and discusses the choice of scattering angle for optimum sensitivity. Experimental results are presented for the coherent scattering of 60 keV gamma-rays by potassium orthophosphate (K/suh2/HPO/sub4/) solutions with densities ranging from 1.0-t.7 g cm/sup-3/. The results demonstrate an improvement in sensitivity by a factor of 1.9, when compared with the coherent/Compton ratio method, for noninvasiv¢ density measurements on low-Z materials.
37385
Deleuze, M.P.
Inspection of high-density materials by means of X- and gammaradiography and X- and gamma-radioscopy M a t e r i a l s E v a l u a t i o n , Vol. 45, No. 8, pp. 939-942 ( A u g . 1987) This paper presents test conducted by the Commissariat a I'Energie Atomique, Paris, France, on uranium testpieces for purposes of evaluating comparatively the capabilities and limitations of x-and gamma-radiography and x- and gamma-radioscopy. The points of comparison are the exposure and inspection times, the radiographic contrast, the defect detection sensitivity, and the choice of radiation source. These tests made it possible to determine the limiting thicknesses of uranium that can be inspected by these two techniques. Accordingly, we decided to replace our existing iridium-192 gammaradiography with 420 kV x-radioscopy and -radiography. 37126
Holt, R.S.; Cooper, M.J.
Gamma-ray scattering NDE N D T I n t e r n a t i o n a l , Vol. 20, No. 3, pp. 161-165 (3 Jun. 1987) Compton scattering of gamma radiation offers an alternative approach for the nondestructive examination of defects in metals and alloys. A prototype scanner based on a 137-Cs isotope has been constructed to evaluate.the inherent sensitivity of the method in characterizing structural defects in bulk materials. The initial results show that voids with linear dimensions of the order of half of the beam width can be detected and located within a small fraction of the beam size. 37125
Anghaie, S.; Diaz, N.J.
Nondestructive detection and sizing of flaws by differential gamma scattering spectrum techniques I S A T r a n s a c t i o n s , Vol. 26, No. 2, pp. 13-33 (1987) This paper describes the results of an experimental program designed to examine the capabilities of the differential gamma scattering technique for high resolution nondestructive testings. The experimental program consisted of two
N D T & E International June 1991
36602
Henderson, I.A.; McGhee, J.
Modelling gamma-source backscatter density gauges I E E P r o c e e d i n g s , Vol. 133, No. 9, pp. 611-617 ( D e c . 1986) Gamma-source backscatter gauges arc used to obtain a nonintrusive measurement of the density of rocks and soils from the surface. The static and moving-source versions of these instruments, which have been developed previously, allow an in situ investigation of a bulk sample of a material. Changes in gauge design and factors affecting the homogeneity of the material alter the backscatter characteristics. A model, which accurately represents the detector in its working environment, is developed for all gamma-source backscatter density gauges. Whereas previous models emulate the absorption and scattering processes, the presented model allows a direct comparison of the maxima and shape, or bandwidth, of the experimental and theoretical predicted results. The model makes this comparison possible through the formulation of characteristic differential equations together with accurate calculations of both the maxima and normalised bandwidth of the characteristics for both versions of these backscatter density gauges. This allows an accurate comparison of design parameters by different routes and could form a basis for new backscatter gauge designs. Fresh applications involving surface measurements of in situ bulk materials could also result from this model. 36582
Schotanus, P.; Eijk, C. W.E.; Hollander, R. W.; Pijpelink, J.
Development study of a new gamma camera I E E E T r a n s a c t i o n s on N u c l e a r Science, Vol. NS-34, No. 1, pp. 272-276 (Feb. 1987) Energy, time and position resolution have been studied, for 511 key annihilation radiation detected in a 15 cm diameter, 8 mm thick BaF/sub2/ crystal coupled to a multiwire proportional chamber filled with TMAE. Properties of other UV scintillators have also been studied.
1 57