Measurement of the Neutron Capture and Fission Cross Sections of ²³⁹Pu and ²³⁵U, 0.02 eV to 200 keV, the Neutron Capture Cross Sections of ¹⁹⁷Au, 10 to 50 keV, and Neutron Fission Cross Sections of ²³³U, 5 to 200 keV

Review and Assessment of Neutron Cross Section and Nubar Covariances for Advanced Reactor Systems

“…16 237 Np(n, el) 2.17 241 Am(n, el) 2.18 243 Am(n, el) 2.19 242m Am(n, el) Chapter 3: Fission Cross Sections 3.1 232 Th(n, f) 3.2 238 U(n, f) 3.3 236 U(n, f) 3. 4 234 U(n, f) 3.5 238 Pu(n, f) 3.6 240 Pu(n, f) 3.7 242 Pu(n, f) 3.8 242 Cm(n, f) 3.9 244 Cm(n, f) 3.10 235 U(n, f) 3.11 233 U(n, f) 3.12 239 Pu(n, f) 3.13 241 Pu(n, f) 3.14 243 Cm(n, f) 3.15 245 Cm(n, f) 3.16 237 Np(n, f) 3.17 241 Am(n, f) 3.18 243 Am(n, f) 3.19 242m Am(n, f) Chapter 4: Inelastic Scattering 4.1 232 Th(n, n' 4.2 238 U(n, n') 4. 3 236 U(n, n') 4.…”

“…4 234 U(n, gamma) 5.5 238 Pu(n, gamma) 5. 6 240 Pu(n, gamma) 5.7 242 Pu(n, gamma) 5.8 242 Cm(n, gamma) 5.9 244 Cm(n, gamma) 5.10 235 U(n, gamma) 5.11 233 U(n, gamma) 5.12 239 Pu(n, gamma) 5.13 241 Pu(n, gamma) 5.14 243 Cm(n, gamma) 5.15 245 Cm(n, gamma) 5. 16 237 Np(n, gamma) 5.17 241 Am(n, gamma) 5.18 243 Am(n, gamma) 5.19 Chapter I…”

“…The improvements of the nuclear reaction modeling and nuclear parameter systematic, developed based on neutron data description of major actinides 232 Th, 233 U, 235 U, 238 U and 239 Pu is shown to provide a sound basis for critical assessment of the fission, capture, inelastic scattering, (n,xn) reaction cross sections of minor actinides. The main reasons of improvements are justified by: a) refined treatment of the spectra of collective states at equilibrium and saddle deformations; b) consistent description of (n,F) as a superposition of (n, f) and (n, xnf) reactions, (n,xn) reaction cross sections and prompt fission neutron spectra of 235 U, 238 U and 232 Th; c) refined treatment of the collective and intrinsic excitations influence on the level densities at equilibrium and saddle deformations; d) calculation of the exclusive neutron spectra of (n,xn) and (n,xnf) reactions.…”

“…The NNDC produced preliminary uncertainties and correlation matrices for 15 actinides, including 233,234,236 U, 237 Np, 238,240,241,242 Pu, 241,242m,243 Am, 242,243,244,245 Cm [1,2]. These results are crosschecked by making comparisons with measured cross section data and newly calculated data for fission, capture, elastic, inelastic, (n,2n) cross sections and neutron multiplicities of major ( 232 Th, 235,,238 U, 239 Pu)…”

“…For fissile target nuclides 235 U or 239 Pu the spectroscopic properties of the transition states at inner and outer saddles deformations of fissioning 236 U or 240 Pu nuclides, respectively, are of key importance. Though the relative contributions of transition states to the fission cross section are much affected by the target spin value I =7/2 -for 235 U and 1/2 + for 239 Pu and relative heights of the inner and outer fission barrier humps [3,4,5], the fair description of 235 U(n,f) (I =7/2 -) [3], 237 U(n,f) (I =1/2 + ) [5], 233 U(n,f) (I =5/2 + ) and 239 Pu(n,f) (I =1/2 + ) allows to reproduce measured data on capture and inelastic scattering rather reliably. That approach paves the way to prediction of fission, capture, elastic and inelastic scattering cross sections at 1 keV -5 MeV energy range for fissile minor actinide nuclides.…”