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Long-lived gamma-emitting radionuclide activity forming in the 6 Li-D converter neutron field measurements and calculations were conducted for some ITER construction steels. Activation foil method and unfolding techniques were used to measure the neutron flux density; the mean neutron flux density was 2.03E13 n/(cm 2 s) whereas total fluence equalled 9.87E18 cm −2 . The activity measurements were done by means of gamma-ray spectrometry. Activity calculations were done by means of FISPACT-II code and experimentally determined neutron flux. Long-lived gamma emitting radionuclides activity in steel samples was, in average, about 1.9 MBq/g 1 year after activation; the dominant radionuclides were 60 Co, 54 Mn and 58 Co (about 52%, 24% and 20% of total activity respectively). The calculated to experimental values ratio (C/E) for particular radionuclides varies generally in range from 0.52 for 57 Co to 1.38 for 51 Cr. [ABSTRACT FROM AUTHOR]

Abstract: Estimation and characterisation of the neutron-induced radioactivity in fusion reactor materials is the basis for their classification in view of radiotoxicity. In the present study has been performed evaluations of Clearance Index (CI), Contact Dose (CD) and Decay Heat Rate (HR) for a European DEMO concept based on HCLL blanket technology, including their time behaviour and significance of particular nuclides. The main objective was to determine the activation of the various materials and components in order to quantify the amount and characteristics of wastes from the DEMO machine. Calculations of induced activity in the system, indicated sometimes the dominant contribution of very rare reactions or nuclides with hundreds years of decay. Activation and decay heat levels of the components were calculated with the use of FISPACT-2007 and EAF-2007 library, on the basis of neutron fluxes throughout the structures of the tokamak calculated with the use of MCNP and the DEMO model from CCFE. The final material balance was assessed as well. [Copyright &y& Elsevier]

Abstract: Two novel methods of tritium production rate (TPR) measurements applied in HCLL TBM mock-up neutronic experiment are described and discussed. In the first method LiF TLD detectors used for gamma radiation dose measurements are applied as detectors of −β decay of tritium (T) produced by neutrons. TL signal expressed as mGy/h is proportional to energy accumulated in self-irradiation process (SI). However, the TL signal is proportional to tritium activity generated in detector material, recalculation to Bq/mg requires calibration by independent measurement of T activity in the TLD. In our experiments determination of this activity was performed by LSC technique. Good correlation between the 3H activity and TLD signal was observed. The second presented method is based on direct measurement of T in LiPb material with the use of LSC spectrometer. Dissolution of LiPb in nitric acid, and than composing aliquot containing well known mass of irradiated LiPb mixed than with scintillation cocktail, is measured in LS spectrometer providing signal proportional to the T activity. It was proved by series of experiments that procedure performed at controlled conditions ensures no loss of tritium while preparation. Optimization measurement conditions with respect of type of the scintillator used and composition of aliquot/scintillator mixture provide counting efficiency above 22%. Sample material for testing the both techniques was irradiated by neutron flux either at nuclear research reactor “Maria”, Świerk, Poland or at the Frascati Neutron Generator Laboratory in HCLL TBM neutronic experiment. Li2CO3 pellets used as reference were irradiated in the same experiment with TLDs, and samples of LiPb-eutectic and then analysed by modified Dierckx method, a well established technique. Measurement results obtained applying the both techniques described above as well as the control Li2CO3 pellets were in very good consistency. Direct measurements of T produced in LiPb at different depth in HCLL TBM mockup agrees well with MCNP simulation results. Parameters of the simulation provide additionally information on 6Li abundance and Li content in the LiPb mixture. Spread of the T activity observed at the same depth for different samples correspond with inhomogeneity of the eutectic composition investigated and reported. Direct measurement of T activity seems to be the very promising and relatively simple method of validation of neutronic codes and nuclear data capabilities for calculation TPR in fusion relevant materials provided parameters of the irradiated material are well known. [Copyright &y& Elsevier]

Abstract: The radioactivity induced in the divertor (region) of the HCLL plant has been evaluated in two 3-D models—homogenised and heterogeneous ones. It has been established, among others, the following: due to the effect of streaming, the calculations of neutron flux, activity, heating, etc., do not bring adequate results. Even impurities can significantly affect the induced activity. The resonance self-shielding effects prove not negligible. In view of the above, certain recommendations regarding future research in this field have been formulated: the detailed representation in the model of the structure and composition of main elements of the divertor is necessary. The exact knowledge of the material composition of the model elements is needed. Also, the cross-sections for calculations of induced activity are either continuous or when they are group ones, are problem-dependent. [Copyright &y& Elsevier]

Abstract: Cross sections for production of radionuclides in (p,x) reactions on natural iron were measured for protons of 650±4 MeV with the use of HPGe gamma spectrometry and calculated with the MCNPX code. The determined cross section values were compared with the computed and other experimental ones. [Copyright &y& Elsevier]

Abstract: A European nuclear-fusion technology program is currently, except of other acivities, on the stage of validating the capability of neutronic codes and nuclear data for use in the ITER project. This requires a technique for reliable measurements of tritium produced by a neutron flux and these estimates must have a qualified uncertainty. The application of LiF TL detectors, calibrated by the direct measurement of tritium activity using the Liquid Scintillation Counting (LSC) technique, is a new approach to the assessment of the tritium production rate in fusion related benchmark experiments. Lithium Fluoride Thermoluminescent Detectors (TLD) are commonly used for measurements of thermal neutron dose using the 6Li(n,α)3H reaction. The accumulation of radioactive tritium in the LiF detectors is usually considered as an undesired effect to the detectors, increasing intrinsic background after high-dose neutron exposure. The same effect may be exploited for the measurement of generated tritium activity. A TL signal corresponding to the energy deposited in the −β decay of 3H, expressed as mGy/h to be recalculated to Bq/mg, requires calibration by an independent measurement of 3H activity. This calibration can be performed by applying e.g. LSC-technique. A good correlation was obtained in the tested range of tritium activity: 17–25 Bq/mg of LiF (0.080–0.118 mGy/h) with a slope of regression line: 1.75 × 10−4 [mGy/h]/[Bq], r 2 = 0.94. The thermal treatment of the TLDs after irradiation (annealing: 400 °C, 1 h) leads to a loss of 37% of the initial tritium content. Prolonged storage of the irradiated TLDs at room temperature, pressure and humidity causes the escape of less than 5% of the accumulated tritium after 100 days. Thus LiF TLDs after calibration can be used as one of techniques for the assessment of tritium production in neutronic experiments. [Copyright &y& Elsevier]

The purpose of this paper is to show applicability ofmultifractal analysis in investigations of the morphological changes of ultra-structures of red blood cells (RBCs) membrane skeleton measured using atomic force microscopy (AFM). Human RBCsobtainedfromhealthyandhypertensivedonorsas wellas healthy erythrocytes irradiated with neutrons (45 μGy) were studied. The membrane skeleton of the cells was imaged using AFMin a contactmode.Morphological characterization of the three-dimensional RBC surfaces was realized by amultifractal method. The nanometre scale study of human RBCs surface morphology revealed a multifractal geometry. The generalized dimensions Dq and the singularity spectrum f(α) provided quantitative values that characterize the local scale properties of their membrane skeleton organization. Surface characterization was made using areal ISO 25178-2: 2012 topography parameters in combination with AFM topography measurement. The surface structure of human RBCs is complex with hierarchical substructures resulting from the organization of the erythrocyte membrane skeleton. The analysed AFM images confirm a multifractal nature of the surface that could be useful in histology to quantify human RBC architectural changes associated with different disease states. In case of [ABSTRACT FROM AUTHOR]

The development of high quality nuclear data, radiation detectors and instrumentation techniques for fusion technology applications in Europe is supported by Fusion for Energy (F4E) and conducted in a joint and collaborative effort by several European research associations (ENEA, KIT, JSI, NPI, AGH, and CCFE) joined to form the “ Consortium on Nuclear Data Studies / Experiments in Support of TBM Activities ” . This paper presents the neutronics activities carried out by the Consortium. A selection of available results are presented. Among then a benchmark experiment on a pure copper block to study the Cu cross sections at neutron energies relevant to fusion, the fabrication of prototype neutron detectors able to withstand harsh environment and temperature >200 °C (artificial diamond and self-powered detectors) developed for operating in ITER-TBM as well as measurement of relevant activation and integral gas production cross-sections. The latter measured at neutron energies relevant to IFMIF (>14 MeV) and the development of innovative experimental techniques for tritium measurement in TBM. [ABSTRACT FROM AUTHOR]

A dedicated effort on nuclear data validation and nuclear instrumentation techniques for Test Blanket Modules (TBM) in ITER is conducted as an integral part of Fusion for Energy's (F4E) programme to ensure validated nuclear analysis capabilities for fusion technology applications. It is closely linked to nuclear data development activities, which are jointly coordinated and conducted by F4E and nuclear data consortia formed by European research institutions. The current experimental activities, an integral copper validation experiment and gas production experiments in EUROFER elements, as well as activities on the development and testing of candidate nuclear detectors for TBM in ITER and the related design integration assessment are presented in this paper. [ABSTRACT FROM AUTHOR]

Two neutronics experiments have been carried out at 14MeV neutron sources on mock-ups of the helium cooled pebble bed (HCBP) and the helium cooled lithium lead (HCLL) variants of ITER test blanket modules (TBMs). These experiments have provided an experimental validation of the calculations of the tritium production rate (TPR) in the two blanket concepts and an assessment of the uncertainties due to the uncertainties on nuclear data. This paper provides a brief summary of the HCPB experiment and then focuses in particular on the final results of the HCLL experiment. The TPR has been measured in the HCLL mock-up irradiated for long times at the Frascati 14MeV Neutron Generator (FNG). Redundant and well-assessed experimental techniques have been used to measure the TPR by different teams for inter-comparison. Measurements of the neutron and gamma-ray spectra have also been performed. The analysis of the experiment, carried out by the MCNP code with FENDL-2.1 and JEFF-3.1.1 nuclear data libraries, and also including sensitivity/uncertainty analysis, shows good agreement between measurements and calculations, within the total uncertainty of 5.9% at 1σ level. [ABSTRACT FROM AUTHOR]

Abstract: In support of the breeder blanket development program, the EU is conducting a dedicated neutronics R&D effort to provide the basis for the design of nuclear tests to be performed in ITER on the Test Blanket Modules (TBMs). It includes the development of computational tools comprising both Monte-Carlo and deterministic transport, sensitivity and uncertainty codes, the generation of high quality neutron cross-section and covariance data libraries. These are validated experimentally in view of their application in the ITER TBM and the DEMO design. To this purpose, two neutronics experiments have been carried out on mock-ups of both the Helium Cooled Pebble Bed (HCPB) and the Helium Cooled Lithium Lead (HCLL) variants of ITER TBMs, at 14-MeV neutron sources. Redundant experimental techniques have been used to measure the resulting tritium production rate and the neutron and gamma ray spectra which are needed to predict the blanket shielding performance, nuclear power production and all nuclear loads. The comparison of experiment and corresponding calculation is obtained with the associated uncertainty margin based on experimental as well as calculational uncertainties. At the same time, suitable nuclear measuring techniques for TBMs in ITER, in particular for the tritium production, are being developed, optimised, and tested in the mock-up experiments. In particular, the present paper summarizes the preliminary results of the latest of such experiments, i.e. the one conducted on a mock-up of the HCLL blanket. It describes also the dedicated neutronics R&D activities, including the efforts to specify the neutronics tests and objectives in TBMs in ITER, considering the various design concepts. [ABSTRACT FROM AUTHOR]

Abstract: A neutronics experiment on a mock-up of the EU Test Blanket Module (TBM), helium cooled lithium lead concept, is in preparation with the objective to validate the capability of the neutronics codes and nuclear data to predict nuclear responses, such as the tritium production rate (TPR), with qualified uncertainties. Three independent measurements of the TPR will be performed using Li2CO3 pellets. Other measurement techniques have been developed using thermo-luminescence detectors, and diamond detectors covered with 6LiF. Neutron flux spectra will also be measured from fast energies down to thermal energies, relevant for TPR. Comparison of measured quantities (E) with the same calculated quantities (C) will be provided, together with the related uncertainties. The paper presents the results of development of the measurement techniques and their relevance for tritium measurements in TBM in ITER. It presents also the pre-analyses conducted to optimise the mock-up configuration so that the neutron spectra are as similar as possible to those in the TBM in ITER. Sensitivity/uncertainty assessments of the TPR show that the calculation uncertainty due to the uncertainties of the neutron cross sections amounts to a few %, depending on position. The largest uncertainties are due to the elastic scattering (n,2n), and (n,3n) reactions on Pb. [Copyright &y& Elsevier]

A project of fast experimental accelerator driven system called SAD – Subcritical Assembly in Dubna – containing MOX fuel and driven by 660 MeV proton beam is described and analysed. It is shown by design calculations that the necessity exists for certain modifications, allowing for better reliability of measurements of system time characteristics. Different solutions such as: cadmium separation of the biological concrete shield, admixtures of B2O3 to the concrete and certain slowing down of neutrons were analysed. Experiments on a bare spallation targets were conducted and the production of radionuclides in the lead target were measured and compared with calculations. [Copyright &y& Elsevier]