7 th session of the AER Working Group “f “ - Spent Fuel Transmutations Simulations of experimental “ADT systems” Mitja Majerle Nuclear Physics Institute Academy of Sciences Řež, Czech Republic Supercomputer Cray I

AER Working Group “f “ - Spent Fuel Transmutations Introduction  The current state of our experiments : Data from the Phasotron experiment are analyzed In the summer ’04 took place another experiment on the Nuclotron So far ~10 experiments provided us with benchmark data  Simulations – the other half of our work : DCM, MCNP+LAHET, MCNPX (v 2.3.0) Input - parameters of the experiments (setup, beam energy,...) Output – production rates in detectors (can be directly compared to experimental values)

AER Working Group “f “ - Spent Fuel Transmutations Topics  MCNPX  The simulations : the Phasotron experiment the „Energy plus Transmutation“ setup  Exploring parallel computing  Conclusion

AER Working Group “f “ - Spent Fuel Transmutations How MCNPX calculates ?  We input the setup of the experiment  The paths of an incident particle and its reaction products are recorded  Neutrons are counted at the place of our detectors  The neutron spectra are convoluted with the cross-sections for the specific reaction  Result : the number of produced nuclei in the detector foil

AER Working Group “f “ - Spent Fuel Transmutations

First results  Simplified setup : lead target + protons  Good accordance to experimental values for higher energy region  Problem : Homogenous field of lower energy neutrons

AER Working Group “f “ - Spent Fuel Transmutations Low energy neutrons  Concrete walls moderate and reflect fast neutrons  We put the setup inside a narrow concrete corridor and new calculated values suited the experimental ones

AER Working Group “f “ - Spent Fuel Transmutations How MCNPX calculates ?  We input the setup of the experiment  The paths of an incident particle and its reaction products are recorded  Neutrons are counted at the place of our detectors  The neutron spectra are convoluted with the cross-sections for the specific reaction  Result : the number of produced nuclei in the detector foil

AER Working Group “f “ - Spent Fuel Transmutations Neutron spectrum along the target

AER Working Group “f “ - Spent Fuel Transmutations Other uses of simulations  Conclusions based only on simulations Cadmium layer function Criticality calculations  Tests of “strange” experimental results Maximum positions independent of the beam energy ? The best energy of the beam ?

AER Working Group “f “ - Spent Fuel Transmutations Cadmium layer (Vlada Wagner)

AER Working Group “f “ - Spent Fuel Transmutations Criticality calculations (S.R. Hashemi-Nezhad)  We cannot measure the criticality of the system  K eff = 0.22 => 0.4  G = 0.67 => 1.7  Recommendations for improvements are based on simulations

AER Working Group “f “ - Spent Fuel Transmutations Position of the maximum of the neutron field  Some experiments showed that the position of the maximum does not depend of the beam energy !  Simulations on the Phasotron setup confirmed this fact in the energy range MeV

AER Working Group “f “ - Spent Fuel Transmutations Parallel computing with MCNPX  A cluster of computers running LINUX, booted with EtherBoot communicating via MPI (Message Parsing Interface)  MCNPX v f has built-in MPI support  We want to explore : The efficiency of parallel computing in this field Other models ( CEM, ISABEL,..)  First results will be presented on M&C 05 in Auvignon

AER Working Group “f “ - Spent Fuel Transmutations Conclusions  Our experiments ARE a good tool for testing MCNPX capabilities !  MCNPX can be successfully used to get a more profound view of what is going on at our experiments  We follow the main goal of our collaboration : testing simulation codes ! Thank you.