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Characterizing oxide nuclear fuels is difficult due to complex fission products, which result from time-evolving system chemistry and extreme operating environments. Here, we report a machine learning-enhanced approach that accelerates the characterization of spent nuclear fuels and improves the accuracy of identifying nanophase fission products and bubbles. We apply this approach to commercial, high-burnup, irradiated light-water reactor fuels, demonstrating relationships between fission product precipitates and gases. We also gain understanding of the fission versus decay pathways of precipitates across the radius of a fuel pellet. An algorithm is provided for quantifying the chemical segregation of the fission products with respect to the high-burnup structure, which enhances our ability to process large amounts of microscopy data, including approaching the atomistic-scale. This may provide a faster route for achieving physics-based fuel performance modeling.

Tristructural-isotropic (TRISO) fuel particles are being investigated as a potential fuel for both current and advanced reactors. Due to the size of the particles (

The US Department of Energy (DOE) is partnering with fuel vendors to develop enhanced accident tolerant nuclear fuels for Generation III water cooled reactors. In comparison with the standard current uranium dioxide and zirconium alloy system UO2-Zr), the proposed alternative accident tolerant fuel (ATF) should better tolerate loss of cooling in the core for a considerably longer time while maintaining or improving the fuel performance during normal operation conditions. General Electric, Oak Ridge National Laboratory and their partners have proposed to replace zirconium based alloy cladding in current commercial power reactors with an iron-chromium-aluminum (FeCrAl) alloy cladding such as APMT. The use of FeCrAl alloys will greatly reduce the risk of operating the power reactors to produce electricity.

Ultrasonic additive manufacturing (UAM) is a three-dimensional metal printing technology which uses high-frequency vibrations to scrub and weld together both similar and dissimilar metal foils. There is no melting in the process and no special atmosphere requirements are needed. Consequently, dissimilar metals can be joined with little to no intermetallic compound formation, and large components can be manufactured. These attributes have the potential to transform manufacturing of nuclear reactor core components such as control elements for the High Flux Isotope Reactor at Oak Ridge National Laboratory. These components are hybrid structures consisting of an outer cladding layer in contact with the coolant with neutron-absorbing materials inside, such as neutron poisons for reactor control purposes. UAM systems are built into a computer numerical control (CNC) framework to utilize intermittent subtractive processes. These subtractive processes are used to introduce internal features as the component is being built and for net shaping. The CNC framework is also used for controlling the motion of the welding operation. It is demonstrated here that curved components with embedded features can be produced using a five-axis code for the welder for the first time.

Alternative cladding materials to Zr-based alloys are being investigated for accident tolerance, which can be defined as >100X improvement (compared to Zr-based alloys) in oxidation resistance to steam or steam-H2 environments at ≥1473 K (1200 °C) for short times. After reviewing a wide range of candidates, current steam oxidation testing is being conducted on Mo, MAX phases, and FeCrAl alloys. Recently reported low-mass losses for Mo in steam at 1073 K (800 °C) could not be reproduced. Both FeCrAl and MAX phase Ti2AlC form a protective alumina scale in steam. However, commercial Ti2AlC that was not single phase, formed a much thicker oxide at 1473 K (1200 °C) in steam and significant TiO2, and therefore, Ti2AlC may be challenging to form as a cladding or a coating. Alloy development for FeCrAl is seeking to maintain its steam oxidation resistance to 1748 K (1475 °C), while reducing its Cr content to minimize susceptibility to irradiation-assisted α′ formation. The composition effects and critical limits to retaining protective scale formation at >1673 K (1400 °C) are still being evaluated.

Examples are given which prove the ICARUS detector quality through relevant physics measurements. We study the μ decay energy spectrum from a sample of stopping μ events acquired during the test run of the ICARUS T600 detector. This detector allows the spatial reconstruction of the events with fine granularity, hence, the precise measurement of the range and dE/dx of the μ with high sampling rate. This information is used to compute the calibration factors needed for the full calorimetric reconstruction of the events. The Michel ρ parameter is then measured by comparison of the experimental and Monte Carlo simulated μ decay spectra, obtaining ρ=0.72±0.06(stat.)±0.08(syst.). The energy resolution for electrons below ∼50 MeV is finally extracted from the simulated sample, obtaining (Eemeas−EeMC)/EeMC=11%/E[MeV]−−−−−−−√⊕2%., The European Physical Journal C, 33 (2), ISSN:1434-6044, ISSN:1434-6052

Uncomplicated diverticular disease is a common condition in patients older than 50 years. Symptoms are aspecific and overlapping with those of irritable bowel syndrome. Nowadays, patients are often treated with antinflammatory drugs (5-aminosalicilic acid). Our purpose was to evaluate the presence of inflammation in the colonic mucosa of patients with symptomatic uncomplicated diverticular disease compared with subjects without diverticula. Endoscopic biopsies of colon from 10 patients with symptomatic uncomplicated diverticular disease and 10 from subjects without diverticula (controls) were taken. Specimens were homogenised and IL2, IL4, IL5, IL8, IL10, IL12p70, IL13, IFN gamma, TNF alfa (searchlight multiplex technique), TGF beta, transglutaminase type 2 and caspase 9 were measured. Histochemistry for transglutaminase type 2 and TUNEL were performed on the histological sections, in addition to morphologic evaluation, as markers of tissue remodelling and apoptosis. For statistical analysis Student’s t test and Spearman correlation test were used. No histological differences were detected between the patients with an uncomplicated diverticular disease and controls. Mean values of mucosal cytokines and of the other tested parameters did not show statistically significant differences between patients with uncomplicated diverticular disease and controls. Even if based on a small number of patients, the study demonstrates the absence of inflammation in the mucosa of subjects affected by uncomplicated diverticular disease.

The aim of this study was to assess the radiation dose of dose-reduced unenhanced abdominal multidetector computed tomography (MDCT) scan protocols for suspected renal colic in patients within normal weight range and overweight-obese patients and to record the cumulative dose of repeated examinations.Over a 2-year period, we performed 1,026 unenhanced CT examinations for urolithiasis; among these, 675 were performed on 636 patients referred from the emergency department. Patients were divided into two groups on the basis of body mass index (BMI): normal weight (BMI25 kg/m(2) group 1); overweight and obese (BMI25 kg/m(2) group 2). For patients in group 1 and group 2, the protocols of our 64-row scanner prescribe tube current settings at 70 mAs and 150 mAs, respectively. The dose-length product (DLP) estimated by using the manufacturer's software was converted into effective dose (ED).Mean DLP and ED were 177 and 345 mGy/cm and 2.4 and 4.8 mSv for group 1 and group 2, respectively. A subset of 25 patients (3.7%) underwent two or more examinations, with estimated ED ranging from 4.8 to 19.2 mSv.Although radiation dose is nearly double in overweight-obese patients undergoing MDCT, it remains lower than that delivered by a standard-dose protocol. Patients with flank pain, who are often young, are at increased risk for serial CT examinations. Use of a low-dose protocol is mandatory in both normal-weight and obese patients to minimise radiation exposure.

During May 2012, the CERN-CNGS neutrino beam has been operated for two weeks for a total of 1.8 10^17 pot in bunched mode, with a 3 ns narrow width proton beam bunches, separated by 100 ns. This tightly bunched beam structure allows a very accurate time of flight measurement of neutrinos from CERN to LNGS on an event-by-event basis. Both the ICARUS-T600 PMT-DAQ and the CERN-LNGS timing synchronization have been substantially improved for this campaign, taking ad-vantage of additional independent GPS receivers, both at CERN and LNGS as well as of the deployment of the "White Rabbit" protocol both at CERN and LNGS. The ICARUS-T600 detector has collected 25 beam-associated events; the corresponding time of flight has been accurately evaluated, using all different time synchronization paths. The measured neutrino time of flight is compatible with the arrival of all events with speed equivalent to the one of light: the difference between the expected value based on the speed of light and the measured value is tof_c - tof_nu = (0.10 \pm 0.67stat. \pm 2.39syst.) ns. This result is in agreement with the value previously reported by the ICARUS collaboration, tof_c - tof_nu = (0.3 \pm 4.9stat. \pm 9.0syst.) ns, but with improved statistical and systematic errors., Comment: 21 pages, 13 figures, 1 table

The final analysis of the data collected in a search for free $$n - \bar n$$ oscillations is presented. The experiment has been carried out at the Triga Mark II reactor of the Pavia University. A thermal neutrons current of 3.2·1010s−1 propagates in a quasi-free condition for an average time of flight of 8ms and impinges on two thin targets. The possible antineutron annihilation products would be detected in the first target. The second target works as a monitor of the background. No evidence for $$n - \bar n$$ transitions is found. A lower limit of 4.9·105s (90% c.l.) has been reached, with «zero» signal and with «zero» background events.

A non-destructive system for determination of silver traces in air particulates collected on cellulose filters is described, based on neutron activation followed by110Ag β− counting instead of the 657.7 keV γ-ray. The determination limit (for 10% confidence limit) is estimated to be about 10−9 g. The method is easily applicable to the determination of silver in cloud seeding experiments, since the filters themselves provide a consistent and fairly uniform source and samples are collected in general far from industrial areas, where the concentration of possible interfering elements in air is reasonably low.

The concentration of 7 elements (Na, Al, Mg, Ti, Ca, V, Mn) was determined by Neutron Activation Analysis in 35 samples of pottery and 14 samples of clay. The samples were collected in Mothia (a Phoenician stronghold in Sicily during 5th–4th century B. C.) and in its neighbourhoods. Cluster analysis of the data showed that most of the samples are homogeneous and confirmed the archaeological evidence that they are mostly local ware. The detailed results of the analyses are reported and the technique used for cluster analysis is described.

The performance of B+Cd tilter in activation analysis of biological materials is briefly discussed and compared with that of a composite filter recently proposed.

The β- and γ-radiations from185W have been investigated by means of an intermediate image β-spectrometer, a proportional counter spectrometer and a scintillation spectrometer. The disintegration has been found to be complex. It was found that the maximum energy of the main β-spectrum (90 per cent) was 426 keV and that the β-transition goes to the ground state of185Re. A faint γ-ray of 55.6 keV was detected and found to correspond to an excited level in185Re. The γ-ray arises from a magnetic dipole transition. Spin and parity have been assigned; a decay scheme is proposed.

The possibility of the β decay of169Er to the known rotational levels of169Tm has been investigated. No evidence of a complex decay was found. The transition energy results:Eo= (340 ± 2) keV and the half-life :T1/2 = (9.0± 0.2) d. The low energy transitions of169Tm from the decay of169Yb were investigated with a proportional counter spectrometer and by using a coincidence technique. The 23.4 keV γ-ray arising in the transition between the third and the second rotational level was observed; its relative intensity was obtained. No clear evidence was found of a γ-ray which should have arisen from the de-excitation of the first rotational level.

An investigation of the radiations from181W was made by means of a high transmissionβ-spectrometer, a proportional counter spectrometer and a scintillation spectrometer.181W was found to emit onlyL X- andK X-radiations, characteristic of Ta, arising fromL- andK-capture. The decay energy was found to be:E0=92 keV, and the transition was classified as once forbidden (AI=0, 1; yes). The pairing effect in the region aroundA = 181 from the Suess-Jensen plot is briefly discussed.

Per la misura di usura di utensili da taglio col metodo dei traccianti radioattivi, si esamina l’opportunita di passare in soluzione il truciolo e di eseguire i conteggi in fase liquida, onde evitare correzioni per la geometria della sorgente, l’autoassorbimento ed il backscattering. La misura assoluta dell’usura si effettua paragonando a parita di ogni condizione l’attivita di una soluzione di un frammento dell’utensile attivato con l’attivita della soluzione del truciolo. Come esempio vengono riportati i risultati ottenuti su punte da trapano di diverse caratteristiche meccaniche fatte lavorare in identiche condizioni.

Viene descritto uno spettrometro beta ad immagine intermedia del tipo Slatis-Siegbahn. Si danno i risultati delle prove di focalizzazione ed alcuni esempi di spettri ottenuti.

A multiplate cloud chamber has been operated at mountain altitude, yielding 16 000 photographs of random expansions. This paper is intended to study the production of electronic component in nuclear disintegrations induced in lead by cosmic ray particles of moderately high energy. Assuming the neutral meson hypothesis, the ratio of the numbers of neutral of charged π-mesons forming in these disintegrations is derived to be 0.42±40%. The probability of production of electron-photon component in nucleon-Pb nucleus collisions is suggestively reported for two energy intervals: the indicative values are about 0.3 and 0.6 times the geometrical cross-section, for incident particle-energies centered, respectively, around 2 and 6 GeV. It is remarked that the results obtained, though rather poor statistically, are believed to be unaffected by instrumental selections.

The β-ray spectrum of89Sr was investigated in an intermediate image β-ray spectrometer. The transition energy was found to be:E0=1.462±0.005 MeV. The spectral shape from the end-point down to about 140 keV agrees with what is to be exspected from a unique first forbidden transition (ΔI=2, yes). No branching at the 0.913 MeV isomeric level of89Y (γ/β