Benchmark calculation of APOLLO2 and SLAROM-UF in a fast reactor lattice

Hazama, Taira 

Accuracy in k-infinity and reaction rates is compared between APOLLO2 and SLAROM-UF on a fast reactor infinite pin cell model. In the 1st reference level calculation, APOLLO2 and SLAROM-UF agree with the reference value of k-infinity obtained by a continuous energy Monte Carlo calculation within 50 pcm. However, larger errors are observed in a particular reaction rate and energy range. A major problem common to both codes is in the cross section library of Pu in the unresolved energy range. In the 2nd reference level calculation, which is based on the ECCO 1968 group structure, both results of k-infinity agree with the reference value within 100 pcm. The resonance overlap effect is observed by several percents in cross sections of heavy nuclides. In the standard level calculation based on the APOLLO2 library creation methodology, a discrepancy appears by more than 300 pcm. SLAROM-UF original standard level calculation is the best among the standard level calculations.