Program - Brookhaven National Laboratory

The CONRAD code is an object-oriented software tool developed at CEA Cadarache since 2005 to deal
with problems arising during the evaluation process (data assimilation and analysis, physical modeling,
propagation of uncertainties, etc. . . ).
This paper will present the most recent developments concerning the experimental and theoretical aspects
as well as the improvements in term of interface. The experimental descriptions capabilities have been
enhanced thanks to the implementation of both analytical (Chi-Square, Gaussian) and Monte-Carlo resolution
functions which are required for neutron resonance shape analysis. On the theoretical aspects, efforts
have been focused on the continuum energy part with the wrapping of the ECIS and TALYS codes and
the management of optical model/statistical parameters. These new features make possible for Conrad to
currently perform evaluations from 0eV to 20MeV.
Concerning the interfacing developments, a multigroup cross-sections generating tool and an ENDF parser
have been recently improved to produce multigroup cross-section covariance matrices in the frame of the
JEFF project.
Each development aspect is illustrated with several examples and comparisons with other codes (SAMMY,
REFIT) and some forecasted features are detailed as well.
PR 98
Zirconium Evaluations for ENDF/B-VII.2 for the Fast Region
David Brown, BNL. Ramon Arcilla, BNL. Roberto Capote, IAEA. Said Mughabghab, BNL. Michal
Herman, BNL. Andrej Trkov, Jozef Stefan Institute.
We have performed a new combined set of evaluations for 90-96Zr, including new resolved resonance parameterizations
from Said Mughabghab for 90,91,92,94,96 Zr and fast region calculations made with EMPIRE-3.1.
Because 90 Zr is a magic nucleus, 90 Zr is nearly spherical. Therefore, all even-even nuclei in the evaluation
set were evaluated using EMPIRE’s OPTMAN coupled channels code and a new soft-rotor optical model
potential. This then led to improved (n,el) angular distributions, helping to resolve improper leakage in
the older ENDF/B-VII.1β evaluation in KAPL proprietary, ZPR and TRIGA benchmarks. Another consequence
of 90 Zr being a magic nucleus is that the level densities in both 90 Zr and 91 Zr are unusually low
causing the (n,el) and (n,tot) cross sections to exhibit large fluctuations above the resolved resonance region.
To accomodate these fluctuations, we performed a simultaneous constrained generalized least-square
fit to (n,tot) for all isotopic and elemental Zr data in EXFOR, using EMPIRE’s TOTRED scaling factor.
TOTRED rescales reaction cross sections so that the optical model calculations are unaltered by the rescaling
and the correct competition between channels is maintained. In this fit, all (n,tot) data in EXFOR
was used for Ein ¿ 100 keV, provided the target isotopic makeup could be correctly understood, including
spectrum averaged data and data with broad energy resolution. As a result of our fitting procedure, we
have full cross material and cross reaction covariance for all Zr isotopes and reactions.
PR 99
Updated and Revised Neutron Reaction Data for 233 U
Baosheng Yu, Guochang Chen, Hua Zhang, China Nuclear Data Center, China Institute of Atomic
Energy. Wentian Cao, Guoyou Tang, School of Physics and State Key Laboratory of Nuclear Physics and
Technology, Peking University.
The updated and revised evaluation of a complete set of n+ 233 U nuclear data from 10 −5 eV ∼ 20 MeV were
carried out and recommended based on the evaluated experimental data and the feedback information of
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