Status report to the DOE Nuclear Data Committee. [ORNL]

Abstract

The report was mostly generated through a review of abstracts of work completed to the point of being subjected to some form of publication in the open literature, formal ORNL reports, ORNL technical.memoranda, progress reports, or presentation at technical conferences. As much as possible we have reproduced the complete abstract of the original publication with only minor editing. In a few cases •progress reports were written specifically for this publication. The editors have selected the materials to be included in this report on the basis of perceived interests of DOE Nuclear Data Committee members and cannot claim completeness.

Recent Developments in Neutron Dosimetry and Damage Calculations for Fusion Materials Irradiations

“…As an example, a preliminary test has been conducted for the Ti(n,x)47sc reaction. The STAY'SL [4] computer code was used to readjust the cross section as shown in Figure 1 The results agree well with new measurements [5]. The adjustment started with ENDF/B-V cross sections and considered new integral activities and spectra.…”

Progress in the Evaluation and Validation of n+56,57Fe Cross Sections

“…The resonance parameters of 56 Fe are essentially those evaluated by Perey and Perey [24] which were included in the Fröhner evaluation in the JEF-2.2 library [25]. Some typos in the original evaluation were corrected (one resonance energy was changed from 767.240 keV to 766.724 keV and the spurious resonance at 59.5 keV was deleted [2]).…”

“…It was already noted by Perey and Perey [24] that there are missing levels above 400 keV and they did not consider evaluated resonance parameters reliable in that energy range and suggested using average resonance parameters to describe data there. This situation imposes constraints on the use of reconstructed angular distributions from evaluated resonance parameters; non-zero angular momentum states ("p" and "d" waves) are very important The resonance parameters of 57 Fe were not changed compared to the ENDF/B-VIII.0 evaluation, but the 57 Fe cross sections in the fast neutron range above 190 keV were modified as described in Section 2.3.…”

New ideas in dosimetry and damage calculations for fusion materials irradiations

“…Combining all of these data along with previous me ^surements allows us to adjust the neutron cross sections. These adjustments were performed with the STAY'SL [6] computer code which performs a generalized least-squares calculation considering uncertainties in the cross sections, activation measurements, and reference spectra. This technique is especially valuable in cases where the cross sections are not well-known or difficult to measure more directly.…”