Measurements and evaluation of 54-fe in the kev neutron energy region
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Authors
Singh, Sukhjinder
Issue Date
2025-05
Type
Electronic thesis
Thesis
Thesis
Language
en_US
Keywords
Nuclear engineering and science
Alternative Title
Abstract
Accurate neutron-induced reaction data is at the precipice of various nuclear applicationsthat require high accuracies to reduce uncertainties in calculations involving nuclear data
when simulating nuclear systems. These calculations can vary widely, ranging from burnup
calculations of nuclear power reactors, predictions of stellar abundances, radiation dose calculations behind shielding walls, and more. The nuclear data evaluation process ensures that
the latest high fidelity nuclear data are available for end users to make use of in their simulations and calculations. Iron is an important constituent of many nuclear-grade materials,
and relative to the major isotope of 56Fe, the cross-sections of the minor isotopes of Fe are
not as well-characterized and understood.
RPI has updated the RRR evaluation of 54Fe to improve upon the previously evaluated neutron radiative capture cross section as well as the energy-energy covariance of 54Fe
cross sections. To improve upon the existing 54Fe evaluation, new differential neutron TOF
measurements were performed at the Gaerttner LINAC Center. A radiative capture yield
measurement was performed using an enriched 0.021 a/b metallic 54Fe sample using an array
of C6D6 detectors to provide additional capture yield data below 1 MeV. This measurement
was in good agreement with a previous n TOF experiment, and both suggest that the capture cross section in ENDF/B-VIII.0 is too low. Additionally, a transmission experiment
was conducted using a 6Li glass detector on the same enriched 54Fe sample to constrain the
resonance evaluation. Full experimental nuclear data covariances were generated for both
experiments and were propagated to the fitting of resonance parameters with SAMMY. Together with these experiments and other relevant EXFOR data, an improved set of resonance
parameters were generated along with a resonance parameter covariance matrix (MF=32).
The updated RPI 54Fe evaluation improved the agreement to RPI and EXFOR differential data. Additionally, the RPI evaluation was tested against integral critical experiments
and other shielding experiments and found to have maintained the agreement between calculated and experimental values that was observed with previous evaluations.
Description
May2025
School of Engineering
School of Engineering
Full Citation
Publisher
Rensselaer Polytechnic Institute, Troy, NY