Measurement of (n, γ) cross section of ⁹⁰Zr [Abstract]

Conference · Thu Jul 28 04:00:00 EDT 2022

OSTI ID:1899768

Brown, Jesse M. ^[1]; Guber, Klaus H. ^[1]; Paradela, Carlos ^[2]; Schillebeeckx, Peter ^[2]; Kopecky, Stefan ^[2]

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1. Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
2. European Commission, Geel (Belgium). Joint Research Centre (JRC)

The isotopes of Zr with A = [90, 91, 92, 94] make up more than 97% of naturally occurring Zr and are important to many nuclear applications such as nuclear reactors. One of the attractive qualities of naturally occurring Zr isotopes is that they have a low σγ/σt ratio at most neutron energies, such that they improve the neutron economy in reactors by preferentially scattering neutrons rather than absorbing them. This same quality also presents a challenge to measuring the capture cross section, σγ, of Zr isotopes. The ENDF/B-VIII.0 library has a relative uncertainty of approximately 10-20% for incident neutron energies < 0.1 MeV, and uncertainty greater than 20% for energies > 0.1 MeV for the majority of natural Zr isotopes. This motivated the Nuclear Criticality Safety Program (NCSP) to embark on a campaign to accurately measure and evaluate these isotopes of Zr. Here we will show energy-dependent neutron capture cross section measurements for the first enriched sample to be measured: ⁹⁰Zr. The measurements of isotopically enriched samples are being carried out at the Geel Electron Linear Accelerator (GELINA) facility of the Joint Research Center - Geel (JRC-Geel) of the European Union. As isotopic enrichment is a costly process we are careful not to activate any of the samples, as this may hinder future radiation-sensitive measurements. The activation analysis is presented in a report by Brown et al.. Once we were satisfied that the Zr samples would not be activated by the measurements, the ⁹⁰Zr sample was fabricated at Oak Ridge National Laboratory (ORNL) and shipped to GELINA. The dimensions of the cylindrical sample are approximately 0.12 cm thick and a radius of 2.5 cm. Since ⁹⁰Zr is not chemically reactive to air, bare metallic samples were employed. The sample was measured at a flight path (FP) length of 60 m, using four C₆D₆ detectors on FP14. The final paper will include experimental details and measured cross section data for ⁹⁰Zr compared to current evaluated nuclear data libraries.

• Research Organization: Oak Ridge National Laboratory (ORNL), Oak Ridge, TN (United States)
• Sponsoring Organization: USDOE National Nuclear Security Administration (NNSA), Nuclear Criticality Safety Program (NCSP)
• DOE Contract Number: AC05-00OR22725
• OSTI ID: 1899768
• Country of Publication: United States
• Language: English

Related Subjects

07 ISOTOPE AND RADIATION SOURCES
73 NUCLEAR PHYSICS AND RADIATION PHYSICS
Geel Electron Linear Accelerator (GELINA)
Nuclear Criticality Safety Program (NCSP)
Nuclear Data
Zirconium (Zr)