Antineutrinos produced at nuclear reactors constitute a severe source of background for the detection of geoneutrinos, which bring to the Earth's surface information about natural radioactivity in the whole planet. In this framework we provide a reference worldwide model for antineutrinos from reactors, in view of reactors operational records yearly published by the International Atomic Energy Agency (IAEA). We evaluate the expected signal from commercial reactors for ongoing (KamLAND and Borexino), planned (SNO+) and proposed (Juno, RENO-50, LENA and Hanohano) experimental sites. Uncertainties related to reactor antineutrino production, propagation and detection processes are estimated using a Monte Carlo based approach, which provides an overall site dependent uncertainty on the signal in the geoneutrino energy window on the order of 3%.We also implement the off-equilibrium correction to the reference reactor spectra associated with the long-lived isotopes and we estimate a 2.4% increase of the unoscillated event rate in the geoneutrino energy window due to the storage of spent nuclear fuels in the cooling pools. We predict that the research reactors contribute to less than 0.2% to the commercial reactor signal in the investigated 14 sites. We perform a multitemporal analysis of the expected reactor signal over a time lapse of 10 years using reactor operational records collected in a comprehensive database published at www.fe.infn.it/antineutrino.

Constraints on the Earth's composition and on its radiogenic energy budget come from the detection of geoneutrinos. The Kamioka Liquid scintillator Antineutrino Detector (KamLAND) and Borexino experiments recently reported the geoneutrino flux, which reflects the amount and distribution of U and Th inside the Earth. The Jiangmen Underground Neutrino Observatory (JUNO) neutrino experiment, designed as a 20 kton liquid scintillator detector, will be built in an underground laboratory in South China about 53 km from the Yangjiang and Taishan nuclear power plants, each one having a planned thermal power of approximately 18 GW. Given the large detector mass and the intense reactor antineutrino flux, JUNO aims not only to collect high statistics antineutrino signals from reactors but also to address the challenge of discriminating the geoneutrino signal from the reactor background. The predicted geoneutrino signal at JUNO is 39:7 þ6:5 −5:2 terrestrial neutrino unit (TNU), based on the existing reference Earth model, with the dominant source of uncertainty coming from the modeling of the compositional variability in the local upper crust that surrounds (out to approximately 500 km) the detector. A special focus is dedicated to the 6°× 4°local crust surrounding the detector which is estimated to contribute for the 44% of the signal. On the basis of a worldwide reference model for reactor antineutrinos, the ratio between reactor antineutrino and geoneutrino signals in the geoneutrino energy window is estimated to be 0.7 considering reactors operating in year 2013 and reaches a value of 8.9 by adding the contribution of the future nuclear power plants. In order to extract useful information about the mantle's composition, a refinement of the abundance and distribution of U and Th in the local crust is required, with particular attention to the geochemical characterization of the accessible upper crust where 47% of the expected geoneutrino signal originates and this region contributes the major source of uncertainty.

Materials containing radionuclides of natural\ud origin and being subject to regulation because of their\ud radioactivity are known as Naturally Occurring Radioactive\ud Material (NORM). By following International Atomic\ud Energy Agency, we include in NORM those materials with\ud an activity concentration, which is modified by human\ud made processes. We present a brief review of the main\ud categories of non-nuclear industries together with the levels of activity concentration in feed raw materials,\ud products and waste, including mechanisms of radioisotope\ud enrichments. The global management of NORM shows a\ud high level of complexity, mainly due to different degrees of\ud radioactivity enhancement and the huge amount of worldwide\ud waste production. The future tendency of guidelines\ud concerning environmental protection will require both a\ud systematic monitoring based on the ever-increasing sampling\ud and high performance of gamma-ray spectroscopy.\ud On the ground of these requirements a new low-background\ud fully automated high-resolution gamma-ray spectrometer\ud MCA_Rad has been developed. The design of\ud lead and cooper shielding allowed to reach a background\ud reduction of two order of magnitude with respect to laboratory\ud radioactivity. A severe lowering of manpower cost is\ud obtained through a fully automation system, which enables\ud up to 24 samples to be measured without any human\ud attendance. Two coupled HPGe detectors increase the\ud detection efficiency, performing accurate measurements on\ud small sample volume (180 cm\ud 3\ud ) with a reduction of sample\ud transport cost of material. Details of the instrument calibration\ud method are presented. MCA_Rad system can\ud measure in less than one hour a typical NORM sample\ud enriched in U and Th with some hundreds of Bq kg\ud , with\ud an overall uncertainty less than 5 %. Quality control of this\ud method has been tested. Measurements of three certified\ud reference materials RGK-1, RGU-2 and RGTh-1 containing\ud concentrations of potassium, uranium and thorium\ud comparable to NORM have been performed. As a result,\ud this test achieved an overall relative discrepancy of 5 %\ud among central values within the reported uncertainty

An increasing demand of environmental radioactivity monitoring comes both from the scientific community and from the society. This requires accurate, reliable and fast response preferably from portable radiation detectors. Thanks to recent improvements in the technology, γ spectroscopy with sodium iodide scintillators has been proved to be an excellent tool for in-situ measurements for the identification and quantitative determination of γ ray emitting radioisotopes, reducing time and costs. Both for geological and civil purposes not only (40)K, (238)U, and (232)Th have to be measured, but there is also a growing interest to determine the abundances of anthropic elements, like (137)Cs and (131)I, which are used to monitor the effect of nuclear accidents or other human activities. The Full Spectrum Analysis (FSA) approach has been chosen to analyze the γ spectra. The Non Negative Least Square (NNLS) and the energy calibration adjustment have been implemented in this method for the first time in order to correct the intrinsic problem related with the χ(2) minimization which could lead to artifacts and non physical results in the analysis. A new calibration procedure has been developed for the FSA method by using in situ γ spectra instead of calibration pad spectra. Finally, the new method has been validated by acquiring γ spectra with a 10.16 cm × 10.16 cm sodium iodide detector in 80 different sites in the Ombrone basin, in Tuscany. The results from the FSA method have been compared with the laboratory measurements by using HPGe detectors on soil samples collected particular, the (137)Cs isotopes has been implemented in the analysis since it has been found not negligible during the in-situ measurements.

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