Validation and evaluation of the recently released ADVANTG code is presented in the paper. ADVANTG is a hybrid transport code, which combines a deterministic neutron transport code Denovo with MCNP, a well-known Monte Carlo (MC) transport code. ADVANTG was tested on an ICSBEP labyrinth benchmark where neutron fluxes were measured and calculated in a three-section concrete labyrinth for a 252Cf neutron source. The speed-up factors or the increases in relative efficiency of up to 1400 compared to analog MCNP simulations were achieved using the ADVANTG-generated variance reduction parameters. ADVANTG accelerated the calculations in terms of the CPU time and the calculated values were in good agreement with the experimental values. Additionally, it was shown that no bias was introduced by the ADVANTG code, as the mean values obtained by the ADVANTG accelerated calculation are within statistical uncertainties of the analog calculation. The presented work has shown that ADVANTG is a useful tool for use in solving neutron transport problems in geometries featuring labyrinth.
COBISS.SI-ID: 31058215
The equivalence between the neutron source and flux spectra is often implicitly used in practice although many times the users are not even aware of this. This work identifies two conditions under which the equivalence holds. Namely, if the neutron interaction between the source region and the volume where flux is observed is negligible, and the neutron mean track length in the observed volume does not depend on their energy, source and flux spectra are equivalent. Consequently, a flux determined on a closed surface from a full system calculation can be replaced by an equivalent source for a simplified model including only the region contained by the surface.
COBISS.SI-ID: 29895207
The rod insertion method for control rod worth measurement is explained and past as well as recent developments are outlined. The original methodology is updated with a more consistent use of the flux redistribution correction, conversion from dynamic to static reactivity and a new procedure to account for the so-called reactivity overshoot. As an example, the procedure is applied to real measured data from Krško NPP. Resulting integral and differential worth curves are compared with reference measurements by the boron dilution method, where a previously unattainable match is observed. Additional research is presented in order to assess the remaining small deviations. Besides other advantages, the rod insertion method is demonstrated to produce results that are in excellent agreement with those of boron dilution method and can therefore be used as replacement
COBISS.SI-ID: 30971175