BULGARIA - ECFBAN

INSTITUTE FOR NUCLEAR RESEARCH AND NUCLEAR ENERGY
BULGARIAN ACADEMY OF SCIENCES

Boulevard Tsarigradsko shosse 72, Sofia 1784

Telephone: +359 2 758032, 74311
Telefax: +359 2 975 3619
E-mail: krilieva@inrne.bas.bg
            jordanaj@inrne.bas.bg

Director:	Stamenov, Yordan Prof.
Neutron and Reactor Physics Sector:	Janeva, Natalia (Head of Sector)

Neutron Transport Group
Ilieva, Krassimira D. (Head of Group)
Belousov, Sergei I. (Head of the Research Contract)
Antonov, Stoyan Y. (Theory)
Popova, Irina, I.

Neutron Generator SAMES Group
Jordanova, Jordana (Head of the Research Contract)
Penchev, Orlin
Drenska, Miroluba
Trifinov, Alexander

Research activities:
Benchmarks on Neutron Leakage from Iron and Beryllium Slabs and Spheres

Neutron Transport Group - S. Belousov, K. Ilieva, I. Popova, S. Antonov:
Five benchmarks, recommended by the IAEA for nuclear power engineering have been calculated for an assessment of the Iron and Beryllium neutron data from the recent FENDL-1 version. The FENDL/MG-1.0 multigroup data processed in the IAEA by NJOY code are in VITAMIN-J energy structure in MATXS format. These data have been converted to ANISN format by TRANSX code, ported by us to PC version and collected to binary library by LIBFENDL code, that we have created especially for this purpose. Neutron transport calculations have been carried out by the codes ANISN, GRTUNCL and DORT. Two benchmarks important for fusion application correspond to the 14 MeV neutron transmission through Iron sphere shell (Simakov S.P. at al, IPPE, Obninsk) and Iron slabs (Y. Oyama and H. Maekawa, FNS/JAERI). The benchmark on neutron leakage from 25 cm radius Iron sphere with 252Cf source posses to the test FENDL-1 Iron data for LWRs application. The comparison of the measured and calculation results demonstrates discouraged inconsistency when material thickness exceeds 20 cm. Modelling of the angular neutron leakage from 14 MeV source transmitted through Beryllium slabs (H. Maekawa and Y. Oyama at FNS/JAERI) and scalar neutron leakage spectra through sphere shell (Simakov S.P. et al in IPPE, Obninsk) is important to study out the multiplication properties of Beryllium as a fusion blanket material. The measured and calculated results are in relatively good consistency.

Integral benchmark test of neutron data using 14 MeV neutrons

Neutron Generator SAMES Group: J. Jordanova, O. Penchev, M. Drenska, A.Trifinov
Neutron leakage spectra through beryllium, lead and copper slabs with different thickness have been experimentally obtained using proton recoil spectrometer. Reaction rates of threshold activation detectors in copper slabs have been measured. The results have been analysed employing MCNP-4A code and point-wise cross sections from LASL and FENDL data files to calculate the spectra and IRDF-90 dosimetry file to estimate the reaction rates.