Critical experiments have been analyzed to verify a nuclear analysis system for fast reactors used in Japan Nuclear Cycle Development Institute (JNC). The experiments were performed in a collaboration work between JNC and the Institute of Physics and Power Engineering of Russia to dispose Russian surplus weapons plutonium, focusing on the effect of the introduction of uranium-plutonium mixed-dioxide (MOX) fuel and stainless steel reflector into the current BN-600 core that is comprised of UO 2 fuel and blanket.The analysis results agreed well with measured values on most of the nuclear characteristics. The accuracies are comparable to those obtained for the conventional MOX fueled fast reactors. It suggests that the JNC analysis system can analyze accurately nuclear characteristics in uranium fueled cores as well.A significant improvement was achieved on the sodium void reactivity by employing an ultra fine group cell calculation system. A change in adjoint neutron spectrum mostly contributes to the improvement.A discrepancy of more than 20% was found on the fission rate distribution of 235 U or 239 Pu in stainless steel reflector regions, which cannot be solved by introducing continuous Monte Carlo calculation or different nuclear data sets.

No abstract

Critical experiments have been analyzed to verify a nuclear analysis system for fast reactors used in Japan Nuclear Cycle Development Institute (JNC). The experiments were performed in a collaboration work between JNC and the Institute of Physics and Power Engineering of Russia to dispose Russian surplus weapons plutonium, focusing on the effect of the introduction of uranium-plutonium mixed-dioxide (MOX) fuel and stainless steel reflector into the current BN-600 core that is comprised of UO 2 fuel and blanket.The analysis results agreed well with measured values on most of the nuclear characteristics. The accuracies are comparable to those obtained for the conventional MOX fueled fast reactors. It suggests that the JNC analysis system can analyze accurately nuclear characteristics in uranium fueled cores as well.A significant improvement was achieved on the sodium void reactivity by employing an ultra fine group cell calculation system. A change in adjoint neutron spectrum mostly contributes to the improvement.A discrepancy of more than 20% was found on the fission rate distribution of 235 U or 239 Pu in stainless steel reflector regions, which cannot be solved by introducing continuous Monte Carlo calculation or different nuclear data sets.

The JASPER Experiment had been conducted to obtain useful information on FBR shielding analysis accuracy. Results obtained from the post-experimental analyses are summarized in this paper. Both characteristics for bulk shielding attenuation and streaming of neutron through configurations consisting of several materials including B 4C, stainless steel, sodium and etc. were clarified and the analysis accuracy confirmed. The shielding analysis system for fast reactors has been improved and verified. These experimental data and analytical results were reviewed from a viewpoint of the applicability to the shielding design analysis of the DFBR. Useful information to be utilized in the design study of the DFBR is accumulated through those activities.

This report has been reproduced directly from the best available copy.