Speaker
Władysław Pohorecki
(Faculty of Energy and Fuels)
Description
Measurement and calculations of long-lived radionuclide activity forming in the 14 MeV neutron field, in 66Li-D converter were done, in some steel composites of ITER. The activation was conducted in September, 2014 in the thermal-to-14MeV neutron converter constructed in National Centre for Nuclear Research in Poland. This irradiation facility was placed in the core of MARIA research fission reactor. The activation lasted 135 hours. The steel samples were of 10x10x1 mm plate-shape and of approximately 0.8 g mass. The neutron spectrum in 66LiD converter was assessed as a combination of MCNP simulated spectra and tailored to the measured activity of activation foils. The very high threshold (ca 15 MeV) reactions, Au-197(n,3n)Au-195 and Bi-209(n,3n)Bi-207 were especially useful as indicator of converter neutrons.
Fast neutron fraction (above 1 keV) was 53% and fraction of fast neutrons from 66LiD converter in the energy range above 12.5, 13,5 and 14.2 MeV was respectively 80, 97 and 98.7%. Neutron density in the same energy ranges was respectively 3.5, 3.1 and 2.1 1099 cm-2-2 s-1-1.
The activity measurement of the radionuclides formed in steel composites was done by means of gamma-ray spectrometry.
Activity calculations were done by means of FISPACT-2010 using the activation library EAF-2010 and assessed neutron flux. Total activity of measured gamma emitting radionuclides in steel samples after 20 days of cooling was in the range 185 – 208 MBq/g.
The calculated to experimental values ratio (C/E) differs for particular radionuclides and are in the range 0.63-0.86 for Cr-51, 0.72-0.83 for Mn-54, 0.68-0.85 for Co-58, 1.08-1.24 Fe-59, 1.21-1.40 for Co-57 and 0.0-2.54 for Co-60. Carried out measurements and calculations confirm the presence of high fusion neutron flux and proves that tested converter is one of the strongest available continuous 14 MeV neutron source.
Co-authors
Krzysztof Pytel
(Reactor Research & Technologies Division, National Centre for Nuclear Research, ul. Andrzeja Sołtana 7 05-400 Otwock, Świerk, Poland)
Paweł Jodłowski
(Faculty of Physics and Applied Computer Science, AGH-University of Science and Technology, Al. Mickiewicza 30 30-059 Kraków, Poland)
Rafał Prokopowicz
(Reactor Research & Technologies Division, National Centre for Nuclear Research, ul. Andrzeja Sołtana 7 05-400 Otwock, Świerk, Poland)
Władysław Pohorecki
(Faculty of Energy and Fuels, AGH-University of Science and Technology, Al. Mickiewicza 30 30-059 Kraków, Poland)
