2009 Release of the Evaluated Nuclear Data Library (ENDL2009)

Abstract

LLNL's Computational Nuclear Physics Group and Nuclear Theory and Modeling Group have collaborated to produce the next iteration of LLNL's evaluated nuclear database ENDL2009. ENDL2009 is the second in a series of major ENDL library releases designed to support LLNL's current and future nuclear data needs. This library contains many new evaluations for radiochemical diagnostics, structural materials, and thermonuclear reactions. We have striven to keep ENDL2009 at the leading edge of nuclear data library development by reviewing and incorporating new evaluations as they are made available to the nuclear data community. In addition, ENDL2009 support new features such as energy dependent Q values from fission and unresolved resonances. Furthermore, this is the first ENDL library release to be released in the TDF format. Finally, this release is our most highly tested release as we have strengthened our already rigorous testing regime by adding tests against LANL Activation Ratio Measurements and many more new critical assemblies. Our testing is now being incorporated into our development process and is serving to guide library improvements. Contents

Event-by-event evaluation of the prompt fission neutron spectrum from 239Pu(n, f)

“…We have simulated several foils ( 239 Pu, 233 U, 235 U, 238 U, 237 Np, 51 V, 55 Mn, 63 Cu, 93 Nb, 107 Ag, 121 Sb, 139 La, 193 Ir and 197 Au) which are tests of the (n, f ) and (n, γ) reactions in the Jezebel assembly. In all cases, our simulated values of the activation rates in these foils are either consistent with measured values or previous modeling using a modified version of the ENDF/B-VII.0 nuclear data library [54]. As the fission cross sections for 233 U, 235 U, 238 U, and 237 Np are accurately known and span all incident neutron energies, these tests merely confirm our earlier modeling of plutonium critical assemblies.…”

Event-by-event evaluation of the prompt fission neutron spectrum from239Pu(n,f)

“…Conversely, a well-characterized material can also be used to test the critical assembly flux modeling. We have simulated several foils ( 239 Pu, 233 U, 235 U, 238 U, 237 Np, 51 V, 55 Mn, 63 Cu, 93 Nb, 107 Ag, 121 Sb, 139 La, 193 Ir and 197 Au) which are tests of the (n, f ) and (n, γ) reactions in the Jezebel assembly. In all cases, our simulated values of the activation rates in these foils are either consistent with measured values or previous modeling using a modified version of the ENDF/B-VII.0 nuclear data library [55].…”

“…We have simulated several foils ( 239 Pu, 233 U, 235 U, 238 U, 237 Np, 51 V, 55 Mn, 63 Cu, 93 Nb, 107 Ag, 121 Sb, 139 La, 193 Ir and 197 Au) which are tests of the (n, f ) and (n, γ) reactions in the Jezebel assembly. In all cases, our simulated values of the activation rates in these foils are either consistent with measured values or previous modeling using a modified version of the ENDF/B-VII.0 nuclear data library [55]. As the fission cross sections for 233 U, 235 U, 238 U, and 237 Np are accurately known and span all incident neutron energies, these tests merely confirm our earlier modeling of plutonium critical assemblies.…”