P. Pereslavtsev

Evaluated nuclear data files for accelerator driven systems and other intermediate and high-energy applications

Abstract Nuclear data libraries prepared for the study of processes taking place in materials irradiated by intermediate and high-energy particles (mainly neutrons) are briefly described. These libraries include data needed for transmutation, activation and neutron transport studies for a wide range of target nuclei and incident particle energies.

Status of the McDeLicious Approach for the D-Li Neutron Source Term Modeling in IFMIF Neutronics Calculations

Abstract McDeLicious is an extension to the MCNP Monte Carlo code with the ability to simulate the generation of source neutrons based on D-Li interaction processes. This paper presents an overview of the McDeLicious approach for the D-Li neutron source term modeling including latest code extensions, improvements, validation efforts, and applications to IFMIF neutronics analyses. The current McDeLicious capabilities include the generation of source neutrons and photons based on evaluated d + 6,7Li cross-section data and the sampling of the impinging deuteron beam intensity distribution using fitting functions or probability tables. The McDeLicious software has been updated to comply with the standard of the state-of-the-art version 5 of the MCNP code. A message passing interface program version enables one to run McDeLicious in parallel mode on large computer clusters. McDeLicious is in routine use for IFMIF neutronics calculations employing different nuclear data including a test version of the recent FENDL-3 nuclear data.

Power plant conceptual study - WCLL concept

Abstract A power plant conceptual study (PPCS) has been launched in the framework of the EU fusion program the objective of which is to demonstrate the credibility of fusion power plant design and the claims for safety and environmental advantages and for economic viability of fusion power. A generic set of requirements, addressing in particular safety, operational and economic aspects, has been set out with inputs from industry and from utilities. Four reactor models have been identified for a complete evaluation. The model which is presented in this paper is based on little extrapolation on both physics and technology, using a water cooled divertor based on ITER technology and associated to the water cooled lithium lead (WCLL) blanket.

In-vessel component designs for a self-cooled lithium-lead fusion reactor

Abstract This paper describes an advanced fusion power reactor based on advanced plasma physics assumptions and large technological extrapolation compared with present-day knowledge. In-vessel components are based on the use of SiCf/SiC composites structure and the use of high-temperature Pb–17Li both as coolant and breeder for the blanket. The use of high-temperature super-conducting coils is also expected. A net electrical output of 1500 MWe is assumed. Tritium breeding self-sufficiency and acceptable operating parameters have been obtained. The resulting conceptual power plant has the potential for a thermal efficiency as high as 61% and for reaching good safety standard. The technological extrapolations assumed in this study provide an indication of the necessary R&D for addressing the most critical issues.

Systematics of (n, t) reaction cross sections at 14.6 MeV

Abstract A new semi-empirical formula for the evaluation of cross sections of (n, t) reactions on even-even and odd-even nuclei with atomic number Z ≥ 13 is presented. The formula has been obtained on the basis of analytical expressions describing the triton spectra within the frame of pre-equilibrium exciton, coalescence pick-up and evaporation models.

Thermal Discrete Element Analysis of EU Solid Breeder Blanket Subjected to Neutron Irradiation

Abstract Due to neutron irradiation, solid breeder blankets are subjected to complex thermo-mechanical conditions. Within one breeder unit, the ceramic breeder bed is composed of spherical-shaped lithium orthosilicate pebbles, and as a type of granular material, it exhibits strong coupling between temperature and stress fields. In this paper, we study these thermo-mechanical problems by developing a thermal discrete element method (Thermal-DEM). This proposed simulation tool models each individual ceramic pebble as one element and considers grain-scale thermo-mechanical interactions between elements. A small section of solid breeder pebble bed in a helium-cooled pebble bed (HCPB) is modelled using thousands of individual pebbles and subjected to volumetric heating profiles calculated from neutronics under ITER-relevant conditions. We consider heat transfer at the grain scale between pebbles through both solid-to-solid contacts and the interstitial gas phase, and we calculate stresses arising from thermal expansion of pebbles. The overall effective conductivity of the bed depends on the resulting compressive stress state during the neutronic heating. The Thermal-DEM method proposed in this study provides access to the grain-scale information, which is beneficial for HCPB design and breeder material optimization, and a better understanding of overall thermo-mechanical responses of the breeder units under fusion-relevant conditions.

Data Library IEAF-2001 to Study of Activation of Irradiated Materials

The IEAF-2001 library comprises a collection of individual files for a large number of target nuclides. Each file contains data for neutron-induced reaction cross sections for energies from 10-5 eV to 150 MeV. The target nuclides cover the range from Z=1 to Z=84 i.e. from H to Po. The total amount of the IEAF-2001 library is 679 data files including stable, unstable and isomeric target nuclides. 58 data files correspond to first isomeric states of the target nuclides and 4 files to second target isomers.

Evaluation of nuclear data for transuranium elements in the intermediate energy region

Abstract A semi-empirical method of reaction cross-section evaluation for fissile nuclei irradiated by particles with the energy up to 100 MeV is presented. Using this method fission reaction cross-sections as well as (n,xn), (n,axn) and (n,αxn) reaction cross-sections have been obtained for major transuranium elements.

Overview of the HCPB Research Activities in EUROfusion

In the framework of the EUROfusion’s Power Plant Physics and Technology, the working package breeding blanket (BB) aims at investigating four different BB concepts for an EU demonstration fusion reactor (DEMO). One of these concepts is the helium-cooled pebble bed (HCPB) BB, which is based on the use of pebble beds of lithiated ternary compounds and Be or beryllides as tritium breeder and multiplier materials, respectively, EUROFER97 as structural steel and He as coolant. This paper aims at giving an overview of the EU HCPB BB Research and Development (R&D) being developed at KIT, in collaboration with Wigner-RCP, BUTE-INT, and CIEMAT. The paper gives an outline of the HCPB BB design evolution, state-of-the-art basic functionalities, requirements and performances, and the associated R&D activities in the areas of design, functional materials, manufacturing, and testing. In addition, attention is given also to the activities dedicated to the development of heat transfer augmentation techniques for the first wall and the corresponding testing. Due to their nature as design drivers, a brief overview in the R&D of key HCPB interfacing areas is given as well, namely, the tritium extraction and recovery system, the primary heat transfer and power conversion systems, and safety topics, as well as some specific activities regarding the integration of in-vessel systems through the BB. As concluding remarks, an outline of the standing challenges and future R&D plans is summarized.

Review and validation of shutdown dose rate estimation techniques for application to iter

Abstract Several methodologies have been developed for the calculation of shut-down dose rates based on the use of the Monte Carlo (MC) technique for particle transport simulations including the rigorous two-step (R2S) approach and its recent R2Smesh extension, the direct one-step (D1S) method which employs one single MC transport simulation both for neutrons and decay gammas, and a rough rule of thumb (RoT) approximation based on neutron flux-to-dose conversion factors. The paper discusses these approaches and their applications to ITER with focus on dose rate estimations for the equatorial Test Blanket and Diagnostic Ports. These applications are complemented by benchmark analyses on shut-down dose rate measurements performed on JET showing the validity of the R2S and D1S approaches.