Tungsten Nuclear Data
Evaluation and Integral Validation of Nuclear Data of Tungsten – Candidate Material of Fusion Reactor Diverter
Tech Area / Field
- FUS-HSF/Hybrid Systems and Fuel Cycle/Fusion
3 Approved without Funding
Kurchatov Research Center, Russia, Moscow
- FEI (IPPE), Russia, Kaluga reg., Obninsk\nVNIIEF, Russia, N. Novgorod reg., Sarov
- Forschungszentrum Karlsruhe Technik und Umwelt / Institut fuer Reaktorsicherheit, Germany, Karlsruhe\nTechnische Universität Dresden / Institut für Kern- und Teilchenphysik, Germany, Dresden
Project summaryThe Purpose of the Project is performing complex experimental and calculational researches directed to creating an improved version of nuclear data for tungsten and a set of benchmark experiments for validating these data relevant to activation and transport of neutrons and gamma-rays. The needs for these researches arise, on the one hand, from the high priority of tungsten as a candidate material for the pertor of fusion reactor, and, on the another hand, from deficiencies of reliable nuclear data of tungsten and their validation by integral experiments.
The use of tungsten in a fusion reactor is accompanied by high demands for accuracy of its nuclear data, relevant to transport of radiation, induced by 14-MeV neutrons in the reactor pertor, nuclear heating and activation. At present, the most advanced nuclear data library for fusion reactor applications is the FENDL-2 library. It contains for each relevant nuclide the best versions of evaluated data. They were tested on available integral neutronics benchmark-experiments and used for the ITER design. But the tungsten nuclear data in that library are based on an old ENDF/B-IV file, and do not completely correspond to the modern level of nuclear data evaluation. That requires a new evaluation and the creation of data files not only for the element, but also for the tungsten isotopes. For reliable validation of the evaluated data of tungsten integral benchmark-experiments are necessary in the neutron energy range from thermal up to 14 MeV.
The program of experiments during the first two years consists in manufacturing spherical shells of a tungsten sample and carrying out a cycle of "outer" measurements (neutrons and gamma-ray leakage spectra, neutron leakage multiplication) from four tungsten spheres of outer diameters, ranging from 10 to 22 cm, with a 14 MeV neutron source in the center. During the third year, a set of "inner" measurements (distributions of nuclear reactions and gamma-dose rates on the sphere radius) in the sphere with diameter of 22 cm, where neutron of a 14 MeV source, fission neutrons, as well as reactivity weighting of tungsten sphere in the center of critical fission assembly from highly enriched metallic uranium are to be used. During all the project activation investigations are performed with micro samples of tungsten fabricated by different technology. Planning and performing the experiments are based on corresponding neutronics analyses. By completing the experiments, a complete validation of new elemental and isotopic evaluated data files of tungsten created in the project and their final correction are carried out in the energy range up to 14 MeV.
The components of this work are:
· Measurement in VNIIEF of neutron leakage spectrum from tungsten spheres with a 14-MeV neutron source in the center by the time-of-flight method with stilbene and polystyrene detectors.
· Measurement in VNIIEF of neutron leakage spectrum from tungsten spheres with a 14-MeV neutron source in the center by a gas proportional counter.
· Measurement in VNIIEF of gamma leakage spectrum from tungsten spheres with a 14-MeV neutron source.
· Measurement in RRC KI of the total neutron leakage multiplication in tungsten spheres with a 14-MeV neutron source.
· Activation researches of micro samples from tungsten manufactured by different technology under irradiation by 14 MeV neutrons at the SNEG-13 facility.
· Measurements in RRC KI of local characteristics on neutron and gamma fields on tungsten sphere radius with a 14-MeV neutron source.
· Measurements in VNIIEF of reactivity effects in critical assembly containing the shells of W, 235U (90%), 235U (36%), 238U and polyethylene or beryllium.
· Measurement in VNIIEF of activation and fission integrals in the center of tungsten sphere placed in the center of critical fission assembly.
· Evaluation of nuclear data of the element and isotopes of tungsten.
· Calculational verification of the available versions of nuclear data of tungsten in the energy range from thermal up to 14 MeV.
The proposed work will result in comprehensive information for international testing of evaluated data of tungsten that in final will ensure their qualities on a level of requirements for designing ITER and other potential fusion reactors.
The cooperation in frame of the Project with foreign interested institutions in areas of task definition, working discussions and uses of the results of Project activities is agreed.