Proton activation data file PADF-2. Targets with atomic numbers from 6 to 15

A new version of the Proton Activation Data File, PADF-2, has been prepared for targets from carbon to phosphorus. The file contains cross-sections of all protoninduced reactions occurring at primary energies up to 200 MeV. The new data were obtained using all available experimental data and results of calculations using modern nuclear models and up-to-date versions of computer codes. A preliminary version of the file can be downloaded at: https://t1p.de/3vzu

Arc-dpa and NRT displacement cross-sections for neutron irradiation of materials from Be to Bi calculated using JEFF-4T1, ENDF/B-VIII, JENDL-5, and TENDL-2021 data

Atomic displacement cross-sections for an advanced assessment of radiation damage rates were calculated for materials from Be to Bi using the arc-dpa model and NRT model, and data from JEFF-4T1 test library, the ENDF/B-VIII, JENDL-5, and TENDL-2021 libraries at neutron incident energies from 10-5 eV to the maximum available energy. Obtained cross-sections were extended to 200 MeV using TENDL-2021 data and earlier TENDL versions. Data prepared in ENDF/B and ACE format are available on the site https://bit.ly/3L8ZlH

Improved modelling of alpha-particle emission in nucleon induced reactions

This report discusses the phenomenological approach proposed to estimate the contribution of direct processes to the emission of α-particles in nucleon induced reactions. Using available measured energy distributions, the values of the parameters required for the calculations are obtained. The analysis was performed using the TALYS code

Swelling of safety rod guide tubes in nonuniform fields of temperature and irradiation

AbstractSafety rod guide tubes are important components of fast reactor cores for ensuring safe reactor operation. Their failure or considerable changes of their size may lead to safety rod wedging that is unacceptable. Two guide tubes, one each from BN-350 and BOR-60, were examined post-irradiation to determine the reasons for their deformation and loss of functionality. These tubes were constructed from high-nickel alloy EP-150 and austenitic 18Cr9Ni, respectively.It is found that various forms of deformation of safety rod guide tubes occur due to non-uniform swelling along the tube height, perimeter and across-wall thickness. The swelling gradients can lead to bowing and ovality, and can be accompanied by significant internal stresses within the tube material. The latter can lead to size reduction of guide tube dimension in some directions due to irradiation creep. High levels of swelling-induced residual stresses, in combination with a swelling-induced embrittlement of the tube material, can lead to the tube failure even in the absence of any external loading

New evaluation of general purpose neutron data for stable W-isotopes up to 200 MeV

In the frame of the Power Plant Physics and Technology of EUROfusion, new evaluations of general purpose neutron cross-section data were performed for the 180,182,183,184,186W isotopes covering the neutron energy up to 200 MeV. A special version of the TALYS nuclear model code implementing the geometry dependent hybrid model supplied with models for the non-equilibrium cluster emission was applied for calculations of the nuclide production and the energy distribution of the emitted particles. The parameters of the GDH model were properly estimated using measured data for individual tungsten isotopes. The neutron cross-sections were evaluated making use of available experimental data, systematics including estimated A-dependence of components of gas production cross-sections, and covariance information produced as part of the evaluation process. The BEKED code package, developed at KIT, was applied for calculations of co-variances using a dedicated Monte Carlo method. The evaluated data were processed into standard ENDF data format using the TEFAL code and the FOX module of the BEKED system. The evaluated data files were checked for errors and inconsistencies, processed with the NJOY code into ACE data format, and benchmarked against available integral experiments with MCNP neutron transport calculations

Impact of secondary particles on microdistribution of deposited dose in biological tissue in the presence of gold and gadolinium nanoparticles under photon beam irradiation

It is experimentally proven that nanoparticles of high-Z materials can be used as radiosensitizers for photon beam therapy. In the authors' opinion, data available as of today on the impact of secondary particles (electrons, photons and positrons generated in biological tissue by penetrating beam of primary photons) on the distribution of deposited dose during photon beam therapy in the presence of nanoparticles, are insufficient. Investigation of this impact constituted the main goal of this work. Two-stage simulation was performed using Geant4 platform. During the first stage a layer of biological tissue (water) was irradiated by monoenergetic photon sources with energies ranging from 10 keV to 6 MeV. As the result of this modeling spectra of electrons, photons and positrons were obtained at the depth of 5 cm. During the second stage the obtained photon spectra were used to irradiate gold, gadolinium and water nanoparticles. Radial distributions of energy deposited around nanoparticles were obtained as the result of this modeling. Radial DEF (Dose Enhancement Factor) values around nanoparticles of gold and gadolinium positioned in water at the depth of 5 cm were obtained after processing the collected data. Contributions from primary photons and secondary particles (electrons, photons and positrons generated in the layer of water with 5-cm thickness by the penetrating beam of primary photons) in the additional dose deposited around the nanoparticles were calculated as well. It was demonstrated that layer of biological tissue placed between the source of photons and nanoparticles considerably changes the initial spectrum of photons and this change is significant in the analysis of mechanism of radiosensitization of biological tissues by nanoparticles for all energies of photon sources (up to 6 MeV). It was established that interaction of electrons and positrons with nanoparticles does not lead to significant increase of additional dose in the vicinity of their surfaces and can be most likely excluded from consideration in the analysis of radiosensitization mechanism of nanoparticles

Statistical Analysis of Tritium Breeding Ratio Deviations in the DEMO Due to Nuclear Data Uncertainties

For the stable and self-sufficient functioning of the DEMO fusion reactor, one of the most important parameters that must be demonstrated is the Tritium Breeding Ratio (TBR). The reliable assessment of the TBR with safety margins is a matter of fusion reactor viability. The uncertainty of the TBR in the neutronic simulations includes many different aspects such as the uncertainty due to the simplification of the geometry models used, the uncertainty of the reactor layout and the uncertainty introduced due to neutronic calculations. The last one can be reduced by applying high fidelity Monte Carlo simulations for TBR estimations. Nevertheless, these calculations have inherent statistical errors controlled by the number of neutron histories, straightforward for a quantity such as that of TBR underlying errors due to nuclear data uncertainties. In fact, every evaluated nuclear data file involved in the MCNP calculations can be replaced with the set of the random data files representing the particular deviation of the nuclear model parameters, each of them being correct and valid for applications. To account for the uncertainty of the nuclear model parameters introduced in the evaluated data file, a total Monte Carlo (TMC) method can be used to analyze the uncertainty of TBR owing to the nuclear data used for calculations. To this end, two 3D fully heterogeneous geometry models of the helium cooled pebble bed (HCPB) and water cooled lithium lead (WCLL) European DEMOs were utilized for the calculations of the TBR. The TMC calculations were performed, making use of the TENDL-2017 nuclear data library random files with high enough statistics providing a well-resolved Gaussian distribution of the TBR value. The assessment was done for the estimation of the TBR uncertainty due to the nuclear data for entire material compositions and for separate materials: structural, breeder and neutron multipliers. The overall TBR uncertainty for the nuclear data was estimated to be 3~4% for the HCPB and WCLL DEMOs, respectivel