Nuclear Data Needs and Capabilities for Applications Whitepaper
Abstract not provided
22 GENERAL STUDIES OF NUCLEAR REACTORS↗
Engineering topics
Sonzogni, A
Publications and source records attributed to Sonzogni, A.
Improvements on Decay Heat Summation Calculations by Means of Total Absorption Gamma-ray Spectroscopy Measurements
The decay heat of fission products plays an important role in predictions of the heat released by nuclear fuel in reactors. In this contribution we present results of the analysis of the measurement of the beta decay of some refractory isotopes that were considered possible important contributors to the decay heat in reactors. The measurements presented here were performed at the IGISOL facility of the University of Jyvaeskylae, Finland. In our measurements we have combined for the first time a Penning trap (JYFLTRAP), which was used as a high resolution isobaric separator, with a total absorption spectrometer. The results of the measurements as well as their consequences for decay heat summation calculations are discussed.
11 NUCLEAR FUEL CYCLE AND FUEL MATERIALS↗
Mass Chain Evaluation for A=95
A full evaluation of the mass chain A = 95 has been done in the ENSDF format taking into account all the available data until June 2009. Excited states populated by in-beam nuclear reactions and by radioactive decay have been considered. The 'evp' editor, developed at the NNDC, has been used for the evaluation. This mass chain was last evaluated in 1993. Many new and improved data were reported since then. A total of 13 nuclei have been evaluated.
73 NUCLEAR PHYSICS AND RADIATION PHYSICS↗
AFCI-2.0 Library of Neutron Cross Section Covariances
Neutron cross section covariance library has been under development by BNL-LANL collaborative effort over the last three years. The primary purpose of the library is to provide covariances for the Advanced Fuel Cycle Initiative (AFCI) data adjustment project, which is focusing on the needs of fast advanced burner reactors. The covariances refer to central values given in the 2006 release of the U.S. neutron evaluated library ENDF/B-VII. The preliminary version (AFCI-2.0beta) has been completed in October 2010 and made available to the users for comments. In the final 2.0 release, covariances for a few materials were updated, in particular new LANL evaluations for {sup 238,240}Pu and {sup 241}Am were adopted. BNL was responsible for covariances for structural materials and fission products, management of the library and coordination of the work, while LANL was in charge of covariances for light nuclei and for actinides.
21 SPECIFIC NUCLEAR REACTORS AND ASSOCIATED PLANTS↗
AFCI-2.0 Neutron Cross Section Covariance Library
The cross section covariance library has been under development by BNL-LANL collaborative effort over the last three years. The project builds on two covariance libraries developed earlier, with considerable input from BNL and LANL. In 2006, international effort under WPEC Subgroup 26 produced BOLNA covariance library by putting together data, often preliminary, from various sources for most important materials for nuclear reactor technology. This was followed in 2007 by collaborative effort of four US national laboratories to produce covariances, often of modest quality - hence the name low-fidelity, for virtually complete set of materials included in ENDF/B-VII.0. The present project is focusing on covariances of 4-5 major reaction channels for 110 materials of importance for power reactors. The work started under Global Nuclear Energy Partnership (GNEP) in 2008, which changed to Advanced Fuel Cycle Initiative (AFCI) in 2009. With the 2011 release the name has changed to the Covariance Multigroup Matrix for Advanced Reactor Applications (COMMARA) version 2.0. The primary purpose of the library is to provide covariances for AFCI data adjustment project, which is focusing on the needs of fast advanced burner reactors. Responsibility of BNL was defined as developing covariances for structural materials and fission products, management of the library and coordination of the work; LANL responsibility was defined as covariances for light nuclei and actinides. The COMMARA-2.0 covariance library has been developed by BNL-LANL collaboration for Advanced Fuel Cycle Initiative applications over the period of three years, 2008-2010. It contains covariances for 110 materials relevant to fast reactor R&D. The library is to be used together with the ENDF/B-VII.0 central values of the latest official release of US files of evaluated neutron cross sections. COMMARA-2.0 library contains neutron cross section covariances for 12 light nuclei (coolants and moderators), 78 structural materials and fission products, and 20 actinides. Covariances are given in 33-energy groups, from 10?5 eV to 19.6 MeV, obtained by processing with LANL processing code NJOY using 1/E flux. In addition to these 110 files, the library contains 20 files with nu-bar covariances, 3 files with covariances of prompt fission neutron spectra (238,239,240-Pu), and 2 files with mu-bar covariances (23-Na, 56-Fe). Over the period of three years several working versions of the library have been released and tested by ANL and INL reactor analysts. Useful feedback has been collected allowing gradual improvements of the library. In addition, QA system was developed to check basic properties and features of the whole library, allowing visual inspection of uncertainty and correlations plots, inspection of uncertainties of integral quantities with independent databases, and dispersion of cross sections between major evaluated libraries. The COMMARA-2.0 beta version of the library was released to ANL and INL reactor analysts in October 2010. The final version, described in the present report, was released in March 2011.
21 SPECIFIC NUCLEAR REACTORS AND ASSOCIATED PLANTS↗
Reactor Decay Heat in {sup 239}Pu: Solving the {gamma} Discrepancy in the 4-3000-s Cooling Period
The {beta} feeding probability of {sup 102,104,105,106,107}Tc, {sup 105}Mo, and {sup 101}Nb nuclei, which are important contributors to the decay heat in nuclear reactors, has been measured using the total absorption technique. We have coupled for the first time a total absorption spectrometer to a Penning trap in order to obtain sources of very high isobaric purity. Our results solve a significant part of a long-standing discrepancy in the {gamma} component of the decay heat for {sup 239}Pu in the 4-3000 s range.
22 GENERAL STUDIES OF NUCLEAR REACTORS↗
Nuclear Data Sheets for A = 95
Experimental data on ground and excited state properties for all known nuclei with mass number A=95 have been compiled and evaluated. States populated in radioactive decay, as well as in nuclear reactions, have been considered. For these nuclei, level and decay schemes, as well as tables of nuclear properties, are presented. This work supersedes the 1993 evaluation by T. W. Burrows (1993Bu08). In summary, three isomers were identified in {sup 95}Ag and their respective decay schemes were presented (2003Do09) though only limits on their half lives could be obtained. Besides, high resolution prompt gamma-spectroscopy of {sup 95}Ag has been reported for the first time (2003Ma24). A comprehensive level scheme {sup 95}Pd is now available through the ? decay of {sup 95}Ag (2005Ha45) and the energy of the 21/2+ spin-gap isomer have been established for the first time by observing the gamma-rays from the yrast levels (2003Ma24). The level scheme of {sup 95}Rh has been extended up to 39/2 h by in-beam spectroscopy (1994Ro08) and the {gamma}-delayed proton decays from 96Ag isomers to low-lying levels in {sup 95}Pd have been observed (2003Ba39). The high spin level scheme of {sup 95}Ru has been extended up 43/2 h (1994Gh06) and the lifetime or lifetime limits of several high spin states have been reported (2004Ga08). In {sup 95}Tc, the level scheme has been extended by in-beam spectroscopy (2000Gh01). New data on high spin states in {sup 95}Mo have been available through in-beam spectroscopy using heavy ion reactions [(1998Kh04),(2004Ch18),(2009Zh11)]. The data on {sup 95}Nb has been considerably extended by (t,p) reaction (2005Ra30) and by ({sup 82}Se,p2n{gamma}) reaction (2005Bu08). In {sup 95}Zr, new measurements on {mu} (2005St24) and Q (1998Se01) have become available. Controversy on the existence of a 23 keV state in {sup 95}Zr has been resolved by a high-resolution measurement using magnetic spectrometer (2003So23). New data on high spin states have been published through heavy-ion induced fission [(2002Fo03), (2005Pa48)]. Very recently, new high spin data on {sup 95}Y by n-induced and spontaneous fission decay have been available (2009Ur02). High spin data on {sup 95}Sr have been reported by {gamma}-spectroscopy of spontaneous fission decay (2004Hw04). In {sup 95}Rb, revised estimate of {gamma}-n decay intensity (2002Pf04) and mass excess (2007Ra23) have been reported. New data on {sup 85}Kr it decay have been reported [(2006Ge05),(2007Si17)] and incorporated.
72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗