Nondestructive Gamma-ray Spectrometry Research Articles

Gamma-ray spectrometry attribute analysis of highly enriched uranium based on relative efficiency calibration

Experimental measurements of gamma-ray spectra emitted by a highly enriched uranium sample were performed to improve an algorithm for calculating the enrichment and age. Specifically, passive, non-destructive gamma-ray spectrometry based on a relative efficiency calibration was utilized to determine these key uranium attributes. Comparisons were made with results from the commercial code PC/FRAM and reference values. A comprehensive discussion of the uncertainty and performance of this method is presented.

The degradation of gamma-ray mass attenuation of UOX and MOX fuel with nuclear burnup

Nondestructive gamma-ray spectrometry of nuclear fuel is routinely performed in axial gamma scanning devices and more recently with gamma emission tomography. Following the irradiation of a fresh nuclear fuel with high intensity neutron flux in a nuclear reactor core, a great number of gamma-emitting radionuclides are created. These can be utilized for gamma spectrometric techniques. However, due to the high density and atomic number of the nuclear fuel, self-attenuation of gamma-rays is a challenge, which requires attenuation correction in order to perform accurate analysis of the source activity in the fuel.In this study, the degradation of the gamma-ray mass attenuation with burnup was investigated and, in addition, a predictive model was created by investigating the attenuation change at various gamma energies caused by the burnup of the nuclear fuel. This model is intended for use by spectrometry practitioners inspecting nuclear fuel. To this aim, the energy-dependent gamma-ray mass-attenuation coefficients were investigated as a function of burnup for UOX, and three MOX fuels having different initial Pu contents. The Serpent 2 reactor physics code was used to simulate the burnup history of the fuel pins. The nuclide inventory of the Serpent 2 output is combined with the NIST XCOM database to calculate the mass attenuation coefficients.The mass attenuation coefficient of the fuel was found to decrease with the fuel burnup, in the range of a few percent, depending on the burnup and gamma energy. Also, a theoretical burnup dependent swelling model was imposed on fuel density to see how linear attenuation coefficient of fuel material is changed. Furthermore, greater effect may be expected on the transmitted intensity, where a simulation study of a PWR assembly revealed that the contribution from the inner rods in a scanned fuel assembly increased by tens of percent compared to the one with non-irradiated fresh fuels, when shielded by the outer rods of the assembly. A sensitivity analysis was performed in order to test the effect of a number of geometrical and operational reactor parameters that were considered to potentially effect the mass attenuation coefficient. Finally, a simple-to-use predictive model was constructed providing the mass-attenuation coefficient [cm2/g] of fuel as a function of burnup [MWd/kgHM] and initial Pu content [wt%]. The resulting predictive model was optimized by using the nonlinear regression method.

Radionuclides in Chassigny and Nakhla meteorites of Mars origin: Implications for their pre-atmospheric sizes and cosmic-ray exposure ages

Two Martian meteorites, Chassigny and Nakhla, were analyzed by non-destructive gamma-ray spectrometry to determine concentrations of cosmogenic (26Al) and primordial (40K, 238U, 232Th) radionuclides, and to estimate their pre-atmospheric sizes and cosmic-ray exposure ages. The pre-atmospheric radii of the Chassigny and Nakhla meteorites were estimated using the cosmogenic 26Al to be 17 ​± ​4 and 30 ​± ​5 ​cm, which would result in their total masses of 30–130 and 210–580 ​kg, respectively. This is comparable to the size and mass estimated for other chassignites and nakhlites. The cosmic-ray exposure ages of the Chassigny and Nakhla meteorites estimated using the 26Al – 21Ne isotope pair were 12.8 ​± ​2.5 and 11.6 ​± ​1.8 Myr, respectively, in agreement with published ages of chassignites and nakhlites averaged from several isotope methods, i.e. 11.6 ​± ​0.8 and 12.2 ​± ​0.8 Myr, respectively.

Analyses of radionuclides in the Oued Awlitis 001 and Galb Inal lunar meteorites by HPGe gamma-ray spectrometry

Highly sensitive nondestructive HPGe gamma-ray spectrometry was used for the analysis of the cosmogenic (26Al) and primordial (40K, 238U, and 232Th) radionuclides in the Oued Awlitis 001 and Galb Inal lunar meteorites. The measured 26Al activities were very different (84.0 ± 4.8 dpm/kg vs. 8.4 ± 1.2 dpm/kg, respectively), mainly because of different cosmic-ray exposure ages of the investigated meteorites. The pre-atmospheric radii were 5 ± 1 cm and 11 ± 2 cm, respectively, which would result in total pre-atmospheric masses in the range of 0.7–2.5 kg and 7–23 kg, respectively.

Basic characterization of uranium by high-resolution gamma spectroscopy

Abstract A basic characterization of uranium samples was performed using gamma- and X-ray spectroscopy. The studied uranium samples were eight types of certified reference materials with 235U enrichments in the range of 1–97%, and the measurements were performed over 24 h using a high-resolution and high-purity planar germanium detector. A general peak analysis of the spectrum and the XKα region of the uranium spectra was carried out by using HyperGam and HyperGam-U, respectively. The standard reference sources were used to calibrate the spectroscopy system. To obtain the absolute detection efficiency, an effective solid angle code, EXVol, was run for each sample. Hence, the peak activities and isotopic activities were determined, and then, the total U content and 234U, 235U, and 238U isotopic contents were determined and compared with those of the certified reference values. A new method to determine the model age based on the ratio of the activities of 223Ra and 235U in the sample was studied, and the model age was compared with the known true age. In summary, the present study developed a method for basic characterization of uranium samples by nondestructive gamma-ray spectrometry in 24 h and to obtain information on the sample age.

Unusual morphological features in a presumably Neolithic individual from Riparo della Rossa, Serra San Quirico (Ancona, Italy)

The present study describes human skeletal remains from Riparo della Rossa, a rock shelter in the Marche region (Central Italy). The remains consist of a cranial vault and a few non-articulated postcranial bones, possibly belonging to the same adult individual. As the cranial vault showed some morphological features that are unusual for a modern human (marked prominence of the supraorbital region, very prominent nasal bones and rather high thickness of the vault), an accurate anthropological analysis and quantification of the antiquity of the bones were required. The remains were dated with two different absolute dating methods, AMS 14C and 235U– 231Pa non-destructive gamma-ray spectrometry (NDGRS), which produced discordant results: the uncalibrated 14C dating produced 5690±80 BP for the cranial vault and 6110±80 BP for the clavicle; the NDGRS dating produced 10,000±3000 BP for the cranial vault. The sex discriminant morphological characters on the skull are not unequivocal, though the masculine ones appear more evident. The aims of the present paper are: to provide a morphological and metric description of the remains; to interpret their unusual morphological features; to attempt to attribute them to male or female sex and to one of the possible prehistoric cultural groups, according to dating results (Upper Palaeolithic, Mesolithic or Neolithic). The attribution was obtained by a Bayesian procedure taking into account the reliability of the combined information of morphological/metric features and absolute dating results. The results suggest that the Riparo della Rossa remains are best attributed to a male individual of the Neolithic age.

Performance Characteristics of Sequential Separation and Quantification of Lead‐210 and Polonium‐210 by Ion Exchange Chromatography and Nuclear Spectrometric Measurements

A selective separation and quantitative determination procedure for 210Pb and 210Po in various environmental matrices from different sources such as IAEA-326 soil, phosphate rocks (PR), and phosphogypsum (PG) was developed. The tested samples were digested sequentially using concentrated mineral acids (HF, HNO3) by a programmable high-pressure microwave digestion system. The sample solution was loaded onto a preconditioned ion exchange column (Sr-resin) for chromatographic separation. Polonium-210 was eluted by 6 M HNO3 then spontaneously deposited onto polished silver discs to be measured using low-background alpha spectrometry. Lead-210 was sequentially eluted using 6 M HCl solution, precipitated as lead oxalate, dissolved in HNO3 solution, and mixed with scintillation cocktail to be measured by liquid scintillation counting (LSC). Performance of the developed procedure was tested using a reference soil (IAEA-326), with recommended isotope values, that was used as a quality control to assess separation and quantification efficiency (recovery %). The minimum detectable activities of 210Pb and 210Po were found to be 24 and 0.28 Bq kg(-1) for the measurements using LSC and alpha spectrometry, respectively. The recoveries (%) of 210Pb and 210Po were found to be 80 and 60%, respectively. To test the validity of the proposed LSC method, a comparative study was performed by measuring 210Pb activity concentration in test samples by nondestructive gamma-ray spectrometry.

Traceability in the amount-of-substance analysis of natural potassium, thorium and uranium by the method of passive gamma-ray spectrometry

This paper describes the amount-of-substance analysis of the long-lived naturally occurring radionuclides 40K, 232Th, 235U and 238U by the method of non-destructive passive gamma-ray spectrometry. Calibrands used were standard reference materials and high-purity analytical grade chemicals. Traceability of the measured results to reference materials was established. The emission probabilities of several high-energy gamma-rays were determined. High-energy gammas were measured to decrease the effect of gamma self-attenuation.

Modified Conversion Ratio Measurement in Light Water-Moderated UO2Lattices

To investigate the accuracy of the neutronic calculations in various neutron spectra, the modified conversion ratios [(MCR): ratio of {sup 238}U capture rate-to-total fission rate] of four kinds of light water-moderated UO{sub 2} fuel lattices were measured. In the measurements, the relative reaction rates of {sup 238}U capture and total fission were obtained from the nondestructive gamma-ray spectrometry of {sup 239}Np and {sup 143}Ce, respectively, which accumulated in the fuel rod irradiated at the Tank-Type Critical Assembly. The moderator-to-fuel volume ratios V{sub m}/V{sub f} of the measured lattices were 1.50 (undermoderate) to 3.00 (overmoderate). The measured MCRs were 0.477 {+-} 0.014(V{sub m}/V{sub f} = 1.50), 0.434 {+-} 0.013(1.83), 0.383 {+-} 0.011(2.48), and 0.356 {+-} 0.011(3.00), respectively. The Monte Carlo calculation employing the JENDL-3 library showed good agreement with the experiments for all the cores, although they showed a tendency of overestimation for larger values of MCR, as shown in the case of UO{sub 2} tight lattices. Therefore, it was concluded that, for the cores investigated, the accuracy of the neutronic calculation method currently used was very good.

Determination of the Modified Conversion Ratio of Light-Water-Moderated Uranium-Plutonium Mixed-Oxide-Fuel Lattice

The modified conversion ratio (MCR) (the ratio of the {sup 238}U capture rate to the total fission rate) in a light-water-moderated uranium-plutonium mixed-oxide (MOX-) fuel lattice was measured for four types of lattices with different plutonium enrichment. In the current method, the relative reaction rates of {sup 238}U capture and total fission were obtained from nondestructive gamma-ray spectrometry of {sup 239}Np and fission products, respectively, which accumulated in the fuel rod irradiated at the Tank-Type Critical Assembly. The measured results of the fission rates derived from two different fission products agreed well with each other, and the measured MCRs showed good agreement with the results of the Monte Carlo calculation with the whole-core model. Therefore, the current nondestructive method is applicable to the MCR measurement of MOX fuel.

南・北大東島の後期更新世サンゴ化石の非破壊γ線測定による｀２２６´Ｒａ／｀２３８´Ｕ年代

The 226Ra/238U method based on non-destructive gamma-ray spectrometry is discussed for dating 18 specimens of Pleistocene autochthonous corals in Minami-and Kita-Daito Islands. The 238U and 226Ra contents are indirectly determined by their daughter nuclides of 234Th and 214Pb, respectively, on account of the assumption that the radioactive equilibrium between 288Th and 234Th, and between 220Ra and 214Pb has been maintained. All specimens, initially aragonitic minerals, were powdered, compressed to a disc shape of 50 mm in diameter and made airtight. These specimens have been measured by the Hyper Pure Germanium Detector for 2 to 3 days.The 226Ra/238U dates of 15 specimens in Minami-and 3 specimens in Kita-Daito Island are obtained. The highest frequency of the dates is 120 to 130 ka, and the mean value of those is 128±27 ka, although these dates including counting error (1σ) range from 80 to 190 ka. The mean value of the 226Ra/238U dates is concordant with the weighted average of the 230Th/234U dates of the autochthonous corals, i.e. 123±1 ka, obtained from the same locations of the islands by the method of alpha-spectrometry, which is correlated with the oxygen isotope stage 5 e. In addition, the 226Ra/238U dates of 12 in 18 specimens of the islands correspond to the 230Th/234U dates of the same specimens. This implies that the 226Ra/238U dates by the present study are, as a whole, correlated with the 5 e.The non-destructive 226Ra/238U dating by the gamma spectrometry has advantages that the elaborate and time-consuming chemical procedures are unnecessary and no change in the chemical state occurs in the sample analyzed, hence, the same sample can be used for further investigation after the non-destructive measurement. If smaller counting errors (1 σ) can be made than those by the present study on condition that a detector of lower background is prepared, the detector is heavily shielded, and sample is measured about one week, the non-destructive gamma-ray method will be more valid for dating middle to late Pleistocene corals.

26Al survey of Antarctic meteorites

An 26Al survey by non-destructive gamma ray spectrometry was conducted as part of the preliminary examination effort for Antarctic meteorites. A total of 220 samples were studied. The majority of the samples were from the Allan Hills area; however, samples from several other sites, including the Yamato Mountains, were studied. Compared to worldwide falls and finds, the Antarctic group shows a clear trend toward lower 26Al levels. At leasr 10% of the samples studied were clearly undersaturated in 26Al. The frequency of undersaturated samples suggests that terrestrial ages of several hundred thousand years are common among the Antarctic meteorite collection. The absence of samples with extremely low 26Al implies that the upper limit for terrestrial ages in the Antarctic is on the order of 1 million years.

Comments on “The evidence of ‘CH01’ in sediment core samples of Pacific Ocean collected among FGGE” by Peng Han‐Chang, Zhao Kui‐Huan, and Chen Sui‐Tian

Journal of Geophysical Research: Solid EarthVolume 89, Issue B7 p. 6351-6352 CommentariesFree Access Comments on “The evidence of ‘CH01’ in sediment core samples of Pacific Ocean collected among FGGE” by Peng Han-Chang, Zhao Kui-Huan, and Chen Sui-Tian B. P. Glass, B. P. GlassSearch for more papers by this author B. P. Glass, B. P. GlassSearch for more papers by this author First published: 10 July 1984 https://doi.org/10.1029/JB089iB07p06351Citations: 1AboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL No abstract is available for this article. References Chao, E. C. T., The petrographic and chemical characteristics of tektites, Tektites J. A. O'Keefe, 51– 94, University of Chicago Press, Chicago, Ill., 1963. Chao, E. C. T., E. J. Dwornik, J. Littler, New data on the nickel-iron spherules from Southeast Asian tektites and their implications, Geochim. Cosmochim. Acta, 28, 971– 980, 1964. Eldridge, J. S., G. D. O'Kelley, K. J. Northcutt, Radionuclide concentrations in Apollo 16 lunar samples determined by nondestructive gamma-ray spectrometry, Proc. Lunar Sci. Conf., 4th, 2115– 2122, 1973. Glass, B. P., Microtektite surface sculpturing, Geol. Soc. Am. Bull., 85, 1305– 1314, 1974. Glass, B. P., High-silica (> 60%) lunar glasses in an Apollo 14 soil sample: Evidence for silicic lunar volcanism?, Earth Planet. Sci. Lett., 33, 79– 85, 1976. Glass, B. P., Zhamanshin crater, a possible source of Australasian tektites ?, Geology, 7, 351– 353, 1979. Glass, B. P., R. A. Barlow, Mineral inclusions in Muong Nong-type indochinites: Implications concerning parent material and process of formation, Meteoritics, 14, 55– 67, 1979. Glass, B. P., M. B. Swincki, P. A. Zwart, Australasian, Ivory Coast and North American tektite strewn fields: Size, mass and correlation with geomagnetic reversals and other earth events, Proc. Lunar Planet. Sci. Conf., l0th, 2535– 2545, 1979. Peng, H., K. Zhao, S. Chen, The evidence for ‘CH01’ in sediment core samples of Pacific Ocean collected among FGGE, J. Geophys. Res., 87, 5563– 5565, 1982. Taylor, H. P., S. Epstein, O18/O16 ratios of Apollo 11 lunar rocks and minerals, Proc. Lunar Sci. Conf., 1st, 1613– 1626, 1970. Taylor, S. R., The chemical composition of australites, Geochim. Cosmochim. Acta, 26, 685– 722, 1962. Taylor, S. R., Tektites: A post-Apollo view, Earth Sci. Rev., 9, 101– 123, 1973. Tilton, G. R., Isotopic composition of lead from tektites, Geochim. Cosmochim. Acta, 14, 323– 330, 1958. Citing Literature Volume89, IssueB710 July 1984Pages 6351-6352 ReferencesRelatedInformation

Quantitative estimates of biological mixing rates of North Atlantic pelagic sediments using non-destructive gamma ray spectrometry (GeHP)

Quantitative estimates of biological mixing rates of North Atlantic pelagic sediments using non-destructive gamma ray spectrometry (GeHP)

Determination of210Pb in volcanic gases and210Pb,226Ra,238U in lavas by non-destructive gamma-ray spectrometry

Determination of210Pb in volcanic gases and210Pb,226Ra,238U in lavas by non-destructive gamma-ray spectrometry

137Cs in volcanic rocks.

A non-destructive gamma-ray spectrometry was applied to a number of volcanic products from Japan. Considerable amounts of 137Cs (∼10-13Ci/g) were determined in some volcanic rocks. The presence of 137Cs does not appear to have any relation to the type, age and spatial distribution of the volcanic rocks. This nuclide is not observed in new volcanic products such as ejecta which were collected immediately after eruption, while it is occasionally present in the interior of historic massive lavas. Based on the assumption that the source of the observed 137Cs is a fall-out, 239Pu in volcanic rocks is estimated to be ∼10-15Ci/g, being of the same order of magnitude as has been reported by MEIER et al. (1974).

Gamma-ray spectrometric characterization of volcanic magmas.

Several suites of volcanic rock samples from Japan are investigated by non-destructive gamma-ray spectrometry. Each suite consists of a variety of rock types from a single volcano. The individual volcanoes show a variation in both Th and U series specific activities which parallels the change in K content. Strong coherence between Th and U series activities is also present. A detailed examination of three types of plot, Th series vs. U series, Th series vs. K and U series vs. K, reveals that each volcano has a characteristic pattern. It appears that gamma-ray spectrometric data can be used to distinguish between products from different families of magma.

Non-Destructive Gamma-Ray Spectrometry on Spent Fuels of a Boiling Water Reactor

The spent fuels from the JPDR-I reactor were measured by means of a γ-scanning facility installed in the fuel storage pool. The spatial distributions of the fission products (134Cs and 137Cs) were measured and analyzed in reference to the effects of control rod pattern. The ratios holding between the products of neutron capture and of direct fission (134Cs/137Cs and 154Eu/137Cs) were also examined for its relevance to non-destructive burnup determination. The activity ratios of the fission products can be expressed by a linear function of burnup, provided that corrections are made to account for differences in irradiation history and for spatial variations in the neutron spectrum.

Non-Destructive Gamma-Ray Spectrometry on Spent Fuels of a Boiling Water Reactor

Non-Destructive Gamma-Ray Spectrometry on Spent Fuels of a Boiling Water Reactor

Gamma spectrometry of deep-sea cores and sediment accumulation rates

Deep-sea sediment accumulation rates can be determined by nondestructive gamma ray spectrometry with about as much confidence and with far less effort than by radiochemical alpha spectrometry. Both methods are based on the decay of 230Th within the sediment column, sometimes normalized against232Th; with the gamma ray technique, the isotopes actually measured are 214Bi, a daughter of 230Th, and 208Tl, a daughter of 232Th. Comparison of alpha and gamma measurements on four cores from the South Indian Basin shows that near the tops of some cores 214Bi is not in equilibrium with 230Th, partly because of diffusion of the intervening daughter, 226Ra. If 214Bi is assumed to be equilibrium with 226Ra, a value for the diffusion coefficient of radium in sediments is determined to be in the order of 10−9 to 10−8 cm2s−1, in agreement with previous results. Because such zones of diffusion are shallow compared to the total region of 230Th decay in the sediment, there is little effect on the apparent sediment accumulation rate as determined by the decrease in the 214Bi/208Tl activity ratio down and core.