Lawrence Livermore National Laboratory

Nuclear data is served to MERCURY through a variety of libraries developed by the Computational Nuclear Physics (CNP) group. The CNP website offers a Java applet that allows for a graphical viewing of the cross sections.

The Monte Carlo All Particle Method (MCAPM) library stores data in a pointwise format known as the Evaluated Nuclear Data Library (ENDL). The calculational constants used by MERCURY are generated by the MCFGEN processing code to produce MCF files that contain the nuclear data in both multigroup and pointwise forms. Material temperature dependence is added during the processing step. Energy deposits from nuclear reactions are precomputed by a program called ENDEP, which computes the average energy released by the reactions available for each isotope. Thermonuclear reaction rates and secondary particle distributions are provided by the TDF library.

In MERCURY, the reactions may be limited to specific subsets of the available reactions. For example, only those reactions that solely produce neutrons or only fission reactions. This keeps the decay chain down to a reasonable set of nuclides for many depletion problems.