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At least 181 records · Page 10
All sourcesNASA NTRSDOE OSTI
DOE OSTI2020

Materials Data on SbXe2OF15 by Materials Project

XeF5XeOF4SbF6 crystallizes in the monoclinic P2_1/m space group. The structure is zero-dimensional and consists of two SbF6 clusters, two XeF5 clusters, and two XeOF4 clusters. In each SbF6 cluster, Sb is bonded in an octahedral geometry to six F atoms. There are a spread of Sb–F bond distances ranging from 1.89–1.97 Å. There are five inequivalent F sites. In the first F site, F is bonded in a distorted single-bond geometry to one Sb atom. In the second F site, F is bonded in a single-bond geometry to one Sb atom. In the third F site, F is bonded in a single-bond geometry to one Sb atom. In the fourth F site, F is bonded in a single-bond geometry to one Sb atom. In the fifth F site, F is bonded in a single-bond geometry to one Sb atom. In each XeF5 cluster, Xe is bonded in a 5-coordinate geometry to five F atoms. There are a spread of Xe–F bond distances ranging from 1.95–1.98 Å. There are three inequivalent F sites. In the first F site, F is bonded in a single-bond geometry to one Xe atom. In the second F site, F is bonded in a single-bond geometry to one Xe atom. In the third F site, F is bonded in a single-bond geometry to one Xe atom. In each XeOF4 cluster, Xe is bonded in a square pyramidal geometry to one O and four F atoms. The Xe–O bond length is 1.83 Å. All Xe–F bond lengths are 2.03 Å. O is bonded in a single-bond geometry to one Xe atom. There are two inequivalent F sites. In the first F site, F is bonded in a single-bond geometry to one Xe atom. In the second F site, F is bonded in a single-bond geometry to one Xe atom.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Sb4Au(Xe2F11)2 by Materials Project

Xe4Au(Sb2F11)2 crystallizes in the tetragonal P4_32_12 space group. The structure is zero-dimensional and consists of eight Sb2F11 clusters and four Xe4Au clusters. In each Sb2F11 cluster, there are two inequivalent Sb sites. In the first Sb site, Sb is bonded to six F atoms to form corner-sharing SbF6 octahedra. The corner-sharing octahedral tilt angles are 30°. There are a spread of Sb–F bond distances ranging from 1.89–2.07 Å. In the second Sb site, Sb is bonded to six F atoms to form corner-sharing SbF6 octahedra. The corner-sharing octahedral tilt angles are 30°. There are a spread of Sb–F bond distances ranging from 1.89–2.11 Å. There are eleven inequivalent F sites. In the first F site, F is bonded in a bent 150 degrees geometry to two Sb atoms. In the second F site, F is bonded in a single-bond geometry to one Sb atom. In the third F site, F is bonded in a single-bond geometry to one Sb atom. In the fourth F site, F is bonded in a single-bond geometry to one Sb atom. In the fifth F site, F is bonded in a single-bond geometry to one Sb atom. In the sixth F site, F is bonded in a single-bond geometry to one Sb atom. In the seventh F site, F is bonded in a single-bond geometry to one Sb atom. In the eighth F site, F is bonded in a single-bond geometry to one Sb atom. In the ninth F site, F is bonded in a single-bond geometry to one Sb atom. In the tenth F site, F is bonded in a single-bond geometry to one Sb atom. In the eleventh F site, F is bonded in a single-bond geometry to one Sb atom. In each Xe4Au cluster, there are three inequivalent Xe sites. In the first Xe site, Xe is bonded in a single-bond geometry to one Au atom. The Xe–Au bond length is 2.82 Å. In the second Xe site, Xe is bonded in a single-bond geometry to one Au atom. The Xe–Au bond length is 2.84 Å. In the third Xe site, Xe is bonded in a single-bond geometry to one Au atom. The Xe–Au bond length is 2.77 Å. Au is bonded in a square co-planar geometry to four Xe atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Cr2XeF10 by Materials Project

XeCr2F10 crystallizes in the triclinic P-1 space group. The structure is two-dimensional and consists of one XeCr2F10 sheet oriented in the (1, 0, 0) direction. there are two inequivalent Xe sites. In the first Xe site, Xe is bonded in a linear geometry to two F atoms. There are one shorter (2.00 Å) and one longer (2.21 Å) Xe–F bond lengths. In the second Xe site, Xe is bonded in a linear geometry to two F atoms. There are one shorter (2.02 Å) and one longer (2.18 Å) Xe–F bond lengths. There are four inequivalent Cr sites. In the first Cr site, Cr is bonded to six F atoms to form corner-sharing CrF6 octahedra. The corner-sharing octahedra tilt angles range from 20–41°. There are a spread of Cr–F bond distances ranging from 1.75–1.98 Å. In the second Cr site, Cr is bonded to six F atoms to form corner-sharing CrF6 octahedra. The corner-sharing octahedra tilt angles range from 20–43°. There are a spread of Cr–F bond distances ranging from 1.74–2.08 Å. In the third Cr site, Cr is bonded to six F atoms to form corner-sharing CrF6 octahedra. The corner-sharing octahedra tilt angles range from 31–43°. There are a spread of Cr–F bond distances ranging from 1.76–2.08 Å. In the fourth Cr site, Cr is bonded to six F atoms to form corner-sharing CrF6 octahedra. The corner-sharing octahedra tilt angles range from 31–41°. There are a spread of Cr–F bond distances ranging from 1.75–2.02 Å. There are twenty inequivalent F sites. In the first F site, F is bonded in a single-bond geometry to one Xe atom. In the second F site, F is bonded in a distorted bent 150 degrees geometry to one Xe and one Cr atom. In the third F site, F is bonded in a single-bond geometry to one Cr atom. In the fourth F site, F is bonded in a bent 150 degrees geometry to two Cr atoms. In the fifth F site, F is bonded in a bent 150 degrees geometry to two Cr atoms. In the sixth F site, F is bonded in a single-bond geometry to one Cr atom. In the seventh F site, F is bonded in a bent 150 degrees geometry to two Cr atoms. In the eighth F site, F is bonded in a single-bond geometry to one Cr atom. In the ninth F site, F is bonded in a single-bond geometry to one Cr atom. In the tenth F site, F is bonded in a single-bond geometry to one Cr atom. In the eleventh F site, F is bonded in a distorted bent 120 degrees geometry to one Xe and one Cr atom. In the twelfth F site, F is bonded in a single-bond geometry to one Xe atom. In the thirteenth F site, F is bonded in a bent 150 degrees geometry to two Cr atoms. In the fourteenth F site, F is bonded in a single-bond geometry to one Cr atom. In the fifteenth F site, F is bonded in a bent 150 degrees geometry to two Cr atoms. In the sixteenth F site, F is bonded in a single-bond geometry to one Cr atom. In the seventeenth F site, F is bonded in a single-bond geometry to one Cr atom. In the eighteenth F site, F is bonded in a bent 150 degrees geometry to two Cr atoms. In the nineteenth F site, F is bonded in a single-bond geometry to one Cr atom. In the twentieth F site, F is bonded in a single-bond geometry to one Cr atom.

36 MATERIALS SCIENCE↗
DOE OSTI2025

Application of Indirect Quantification of 133mXe to Calibration of HPGe Detector

The INL Noble Gas Laboratory provides intercomparison samples for the noble gas analysis laboratories as part of the CTBTO PrepCom IMS. Xe-133m is one of the four relevant radionuclides in nuclear explosion monitoring. Without commercially available Xe-133m calibration standards laboratories must create and improve calibration methods. Improvements in calibration methods at the INL NGL benefit the CTBTO PrepCom through better certified values for Xe-133m intercomparison samples. Calibration of High Purity Germanium detectors for Xe-133m quantification is complicated by the coexistence of Xe-133 in samples under analysis. Xe-133 is typically produced in larger quantities, has higher gamma emission probabilities, and its gammas are detected more efficiently than Xe-133m. Xe-133m activity of samples can be indirectly inferred through the 133:133m activity ratio of a batch of material, and the Xe-133 counts in the assay of a small aliquot of the same material. This indirect quantification method can be leveraged to perform detector calibrations for quantification of Xe-133m. Calibrations can be performed by inferring the Xe-133m to certify the sample, and direct counting to determine detector efficiency. A comparison of method results will be shown.

133mXe↗
DOE OSTI2020

Materials Data on SbXe2F9 by Materials Project

Xe2F3SbF6 crystallizes in the monoclinic Cc space group. The structure is zero-dimensional and consists of four SbF6 clusters and four Xe2F3 clusters. In each SbF6 cluster, Sb is bonded in an octahedral geometry to six F atoms. There is three shorter (1.92 Å) and three longer (1.93 Å) Sb–F bond length. There are six inequivalent F sites. In the first F site, F is bonded in a single-bond geometry to one Sb atom. In the second F site, F is bonded in a single-bond geometry to one Sb atom. In the third F site, F is bonded in a single-bond geometry to one Sb atom. In the fourth F site, F is bonded in a single-bond geometry to one Sb atom. In the fifth F site, F is bonded in a single-bond geometry to one Sb atom. In the sixth F site, F is bonded in a single-bond geometry to one Sb atom. In each Xe2F3 cluster, there are two inequivalent Xe sites. In the first Xe site, Xe is bonded in a linear geometry to two F atoms. There are one shorter (2.01 Å) and one longer (2.22 Å) Xe–F bond lengths. In the second Xe site, Xe is bonded in a linear geometry to two F atoms. There are one shorter (2.01 Å) and one longer (2.21 Å) Xe–F bond lengths. There are three inequivalent F sites. In the first F site, F is bonded in a single-bond geometry to one Xe atom. In the second F site, F is bonded in a bent 150 degrees geometry to two Xe atoms. In the third F site, F is bonded in a single-bond geometry to one Xe atom.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on OsXeO3F8 by Materials Project

XeOsO3F8 crystallizes in the tetragonal P4_2/n space group. The structure is zero-dimensional and consists of eight XeOsO3F8 clusters. Xe is bonded in a 5-coordinate geometry to eight F atoms. There are a spread of Xe–F bond distances ranging from 1.98–2.55 Å. Os is bonded in a distorted octahedral geometry to three O and three F atoms. There is two shorter (1.71 Å) and one longer (1.72 Å) Os–O bond length. There are a spread of Os–F bond distances ranging from 2.04–2.09 Å. There are three inequivalent O sites. In the first O site, O is bonded in a single-bond geometry to one Os atom. In the second O site, O is bonded in a single-bond geometry to one Os atom. In the third O site, O is bonded in a single-bond geometry to one Os atom. There are eight inequivalent F sites. In the first F site, F is bonded in a single-bond geometry to one Xe atom. In the second F site, F is bonded in a single-bond geometry to one Xe atom. In the third F site, F is bonded in a water-like geometry to one Xe and one Os atom. In the fourth F site, F is bonded in a distorted single-bond geometry to one Xe and one Os atom. In the fifth F site, F is bonded in a distorted water-like geometry to one Xe and one Os atom. In the sixth F site, F is bonded in a single-bond geometry to one Xe atom. In the seventh F site, F is bonded in a single-bond geometry to one Xe atom. In the eighth F site, F is bonded in a single-bond geometry to one Xe atom.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Re4Xe3(O5F7)2 by Materials Project

Xe3Re4(O5F7)2 crystallizes in the triclinic P-1 space group. The structure is zero-dimensional and consists of one Xe3Re4(O5F7)2 cluster. there are two inequivalent Xe sites. In the first Xe site, Xe is bonded in a linear geometry to two equivalent O atoms. Both Xe–O bond lengths are 2.22 Å. In the second Xe site, Xe is bonded in a linear geometry to one O and one F atom. The Xe–O bond length is 2.06 Å. The Xe–F bond length is 2.43 Å. There are two inequivalent Re sites. In the first Re site, Re is bonded to two O and four F atoms to form distorted corner-sharing ReO2F4 octahedra. The corner-sharing octahedral tilt angles are 21°. There is one shorter (1.71 Å) and one longer (1.72 Å) Re–O bond length. There are a spread of Re–F bond distances ranging from 1.88–2.08 Å. In the second Re site, Re is bonded to two O and four F atoms to form distorted corner-sharing ReO2F4 octahedra. The corner-sharing octahedral tilt angles are 21°. There is one shorter (1.70 Å) and one longer (1.72 Å) Re–O bond length. There are a spread of Re–F bond distances ranging from 1.89–2.28 Å. There are five inequivalent O sites. In the first O site, O is bonded in a single-bond geometry to one Re atom. In the second O site, O is bonded in a single-bond geometry to one Re atom. In the third O site, O is bonded in a single-bond geometry to one Re atom. In the fourth O site, O is bonded in a bent 120 degrees geometry to two Xe atoms. In the fifth O site, O is bonded in a single-bond geometry to one Re atom. There are seven inequivalent F sites. In the first F site, F is bonded in a distorted bent 150 degrees geometry to one Xe and one Re atom. In the second F site, F is bonded in a bent 150 degrees geometry to two Re atoms. In the third F site, F is bonded in a single-bond geometry to one Re atom. In the fourth F site, F is bonded in a single-bond geometry to one Re atom. In the fifth F site, F is bonded in a single-bond geometry to one Re atom. In the sixth F site, F is bonded in a single-bond geometry to one Re atom. In the seventh F site, F is bonded in a single-bond geometry to one Re atom.

36 MATERIALS SCIENCE↗
DOE OSTI2024

Impacts of future nuclear power generation on the international monitoring system

Many countries are considering nuclear power as a means of reducing greenhouse gas emissions, and the IAEA (IAEA, 2022) has forecasted nuclear power growth rates up to 224% of the 2021 level by 2050. Nuclear power plants release trace quantities of radioxenon, an inert gas that is also monitored under international agreements as a signature of nuclear weapons tests. To better understand how nuclear energy growth (and resulting Xe emissions) could affect this global nonproliferation architecture, we modeled daily releases of radioxenon isotopes used for nuclear explosion detection in the International Monitoring System (IMS) that is part of the Comprehensive Nuclear Test-Ban Treaty: 131m Xe, 133 Xe, 133m Xe, and 135 Xe to examine the change in the number of radioxenon detections as compared to the 2021 detection levels. If a 40-station IMS network is used, the detections of 133 Xe in 2050 would range from 82% for the low-power scenario to 195% for the high-power scenario, compared to the detections in 2021. If an 80-station IMS network is used, the detections of 133 Xe in 2050 would range from 83% of the 2021 detection rate for the low-power scenario to 209% for the high-power scenario. Essentially no detections of 131m Xe and 133m Xe are expected. The high growth scenario could lead to a six-fold increase in 135 Xe detections, but the total number of detections is still small (on the order of 1 detection per day in the entire network).

22 GENERAL STUDIES OF NUCLEAR REACTORS↗
DOE OSTI2024

Photonuclear Production of Radioxenon for Air Samples

Radioxenon plays an important role in ensuring compliance with the Comprehensive Nuclear-Test-Ban Treaty due to its ability to be transported through the atmosphere, as well as the fact that the half-lives of its isotopes provide a window long enough to be detected but not long enough that it could become background radiation. This allows it to be correlated with specific events that indicate the testing of nuclear weapons. Idaho National Laboratory supports this mission by providing spiked air samples for monitoring stations to enable instrument calibration and ensure measurement accuracy. We tested a photonuclear method of producing one of the main isotopes of radioxenon, Xe-135. We also tested the separation of Xe-135 from the parent isotope Xe-136 using the method of kinematic recoil. Aluminum coils were placed in quartz ampoules filled with enriched Xe-136 and were irradiated by a bremsstrahlung beam with an endpoint energy of 21 MeV. The results showed that we were not only successful in producing Xe-135 but also that the Xe-135 was deposited into the coil allowing it to be removed from the Xe-136 gas. The coil and the Xe-135 can then be chemically separated. At the time of counting the coil, it was calculated that there was about 18 Bq of activity from Xe-135 remaining in the coil. Future work includes determining the optimal material and geometry of the catcher to maximize the amount of Xe-135 captured.

07 ISOTOPE AND RADIATION SOURCES↗
DOE OSTI2020

Materials Data on TcXeO4F5 by Materials Project

Xe(OF)2TcO2F3 crystallizes in the orthorhombic Cmc2_1 space group. The structure is one-dimensional and consists of four Xe(OF)2 clusters and two TcO2F3 ribbons oriented in the (0, 0, 1) direction. In each Xe(OF)2 cluster, Xe is bonded in a see-saw-like geometry to two equivalent O and two F atoms. Both Xe–O bond lengths are 1.86 Å. There are one shorter (2.05 Å) and one longer (2.10 Å) Xe–F bond lengths. O is bonded in a single-bond geometry to one Xe atom. There are two inequivalent F sites. In the first F site, F is bonded in a single-bond geometry to one Xe atom. In the second F site, F is bonded in a single-bond geometry to one Xe atom. In each TcO2F3 ribbon, Tc is bonded to two O and four F atoms to form distorted corner-sharing TcO2F4 octahedra. The corner-sharing octahedral tilt angles are 23°. Both Tc–O bond lengths are 1.68 Å. There are a spread of Tc–F bond distances ranging from 1.88–2.14 Å. There are two inequivalent O sites. In the first O site, O is bonded in a single-bond geometry to one Tc atom. In the second O site, O is bonded in a single-bond geometry to one Tc atom. There are two inequivalent F sites. In the first F site, F is bonded in a single-bond geometry to one Tc atom. In the second F site, F is bonded in a bent 150 degrees geometry to two equivalent Tc atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on XeNO2F5 by Materials Project

XeOF5NO crystallizes in the monoclinic P2_1/c space group. The structure is zero-dimensional and consists of four nitroxyl molecules and four XeOF5 clusters. In each XeOF5 cluster, Xe is bonded in a pentagonal pyramidal geometry to one O and five F atoms. The Xe–O bond length is 1.83 Å. There are a spread of Xe–F bond distances ranging from 2.07–2.17 Å. O is bonded in a single-bond geometry to one Xe atom. There are five inequivalent F sites. In the first F site, F is bonded in a single-bond geometry to one Xe atom. In the second F site, F is bonded in a single-bond geometry to one Xe atom. In the third F site, F is bonded in a single-bond geometry to one Xe atom. In the fourth F site, F is bonded in a single-bond geometry to one Xe atom. In the fifth F site, F is bonded in a single-bond geometry to one Xe atom.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on OsXe2O3F14 by Materials Project

Xe2OsO3F14 crystallizes in the orthorhombic Pnma space group. The structure is zero-dimensional and consists of four Xe2OsO3F14 clusters. Xe is bonded in a 7-coordinate geometry to seven F atoms. There are a spread of Xe–F bond distances ranging from 1.98–2.44 Å. Os is bonded in a distorted octahedral geometry to three O and three F atoms. There is two shorter (1.71 Å) and one longer (1.72 Å) Os–O bond length. There are one shorter (2.00 Å) and two longer (2.09 Å) Os–F bond lengths. There are two inequivalent O sites. In the first O site, O is bonded in a single-bond geometry to one Os atom. In the second O site, O is bonded in a single-bond geometry to one Os atom. There are eight inequivalent F sites. In the first F site, F is bonded in a single-bond geometry to one Os atom. In the second F site, F is bonded in a single-bond geometry to one Xe atom. In the third F site, F is bonded in a single-bond geometry to one Xe atom. In the fourth F site, F is bonded in a bent 120 degrees geometry to one Xe and one Os atom. In the fifth F site, F is bonded in a single-bond geometry to one Xe atom. In the sixth F site, F is bonded in a bent 150 degrees geometry to two equivalent Xe atoms. In the seventh F site, F is bonded in a single-bond geometry to one Xe atom. In the eighth F site, F is bonded in a single-bond geometry to one Xe atom.

36 MATERIALS SCIENCE↗
DOE OSTI2022

Xenon in the Protoplanetary Disk (PPD), in Two Planets, and a Comet

Isotopic anomalies in several elements, as recently observed in meteorites, are generally interpreted to indicate nonequilibrium environments in the protoplanetary disk (PPD). Here we study reported Xe isotopic compositions on planets Earth and Mars, in a comet, and in meteorites for precursor discrepancies. Abundance variations of inferred presolar nano-diamonds, the carrier phase of the Xe-HL component, appear to be the primary source of nonuniformity of Xe precursors in the PPD, together with mechanisms of mass-dependent fractionation. While planet Mars kept a record of initial solar Xe isotopic abundances, such a record is missing for planet Earth. Xe isotopic abundances in paleo-atmospheres of both planets represent secondary reservoirs that show mass-dependent fractionation effects, but the inferred compositions of their PPD precursors differ: Mars atmospheric precursor Xe had solar isotopic composition, while Earth’s Xe precursor is consistent with a PPD reservoir of low nano-diamond abundance. Strong mass-dependent fractionation effects are observed in Xe components of IAB irons and in Yamato carbonaceous (CY) chondrites, and show that fractionation mechanisms are not restricted to planetary atmospheres. These records show that Xe isotopes in solar system reservoirs are useful tracers of evolutionary processes and of nonequilibrated presolar components in the PPD.

79 ASTRONOMY AND ASTROPHYSICS↗
DOE OSTI2020

Materials Data on OsXe(O2F3)2 by Materials Project

XeOF4OsO3F2 crystallizes in the triclinic P-1 space group. The structure is zero-dimensional and consists of one OsO3F2 cluster and two XeOF4 clusters. In the OsO3F2 cluster, Os is bonded in a 6-coordinate geometry to three O and three F atoms. All Os–O bond lengths are 1.71 Å. There are a spread of Os–F bond distances ranging from 1.96–2.16 Å. There are three inequivalent O sites. In the first O site, O is bonded in a single-bond geometry to one Os atom. In the second O site, O is bonded in a single-bond geometry to one Os atom. In the third O site, O is bonded in a single-bond geometry to one Os atom. There are two inequivalent F sites. In the first F site, F is bonded in a water-like geometry to two equivalent Os atoms. In the second F site, F is bonded in a single-bond geometry to one Os atom. In each XeOF4 cluster, Xe is bonded in a square pyramidal geometry to one O and four F atoms. The Xe–O bond length is 1.83 Å. There are two shorter (2.03 Å) and two longer (2.04 Å) Xe–F bond lengths. O is bonded in a single-bond geometry to one Xe atom. There are four inequivalent F sites. In the first F site, F is bonded in a single-bond geometry to one Xe atom. In the second F site, F is bonded in a single-bond geometry to one Xe atom. In the third F site, F is bonded in a single-bond geometry to one Xe atom. In the fourth F site, F is bonded in a single-bond geometry to one Xe atom.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on HXeF7 by Materials Project

XeHF7 crystallizes in the trigonal R-3 space group. The structure is zero-dimensional and consists of eighteen XeHF7 clusters. Xe is bonded in an octahedral geometry to six F atoms. There are a spread of Xe–F bond distances ranging from 1.99–2.12 Å. H is bonded in a single-bond geometry to two F atoms. There is one shorter (0.96 Å) and one longer (1.65 Å) H–F bond length. There are seven inequivalent F sites. In the first F site, F is bonded in a single-bond geometry to one Xe atom. In the second F site, F is bonded in a single-bond geometry to one Xe atom. In the third F site, F is bonded in a single-bond geometry to one H atom. In the fourth F site, F is bonded in a single-bond geometry to one Xe atom. In the fifth F site, F is bonded in a single-bond geometry to one Xe atom. In the sixth F site, F is bonded in a distorted bent 120 degrees geometry to one Xe and one H atom. In the seventh F site, F is bonded in a single-bond geometry to one Xe atom.

36 MATERIALS SCIENCE↗
DOE OSTI2022

Projected network performance for multiple isotopes using next-generation xenon monitoring systems

Since about 2000 (Bowyer et al., 1998), radioxenon monitoring systems have been under development and testing for the verification of the Comprehensive Nuclear Test-Ban Treaty (CTBT). Operation of the systems since then has resulted in development of a next-generation of systems that are nearly ready for operational deployment. By 2010, the need to screen out civilian sources was well known (Auer et al., 2010; Saey, 2009), and isotopic ratio approaches were soon considered (Kalinowski et al., 2014) to identify specific sources. New generation systems are expected to improve the ability to verify the absence of nuclear tests by using isotopic ratios when multiple isotopes are detected. In this work, thousands of releases were simulated to compute the global detection probability of 131m Xe, 133m Xe, 133 Xe, and 135 Xe at 39 noble gas systems in the International Monitoring System (IMS) for both current and next-generation systems. Three release scenarios are defined at 1 h, 1 d, and 10 d past a 1 kt TNT equivalent 235U explosion event. Multiple cases using from one part in a million to the complete release of the xenon isotopic activity are evaluated for each scenario. Coverage maps and global integrals comparing current and next-generation monitoring systems are presented showing that next-generation noble gas systems will create measurable improvements in the IMS. The global detection probability for 133 Xe is shown to be strong in all scenarios, but only modestly improved by next-generation equipment. However, the detection probability for 131m Xe and 133m Xe increased to about 50% in different scenarios, providing a second detectable isotope for many events. As anticipated from shorter sampling intervals, the expected number of detecting samples roughly doubled and the expected number of detecting stations rose by approximately 50% for all release scenarios. Thus, it might be anticipated that future events would consist of multiple 133 Xe detections and one or more second isotope detections. In conclusion, signals of this nature should increase detection confidence, tighten release location estimates, improve rejection of civilian signals, and lessen the impacts from individual systems being offline for maintenance or repair reasons.

98 NUCLEAR DISARMAMENT, SAFEGUARDS, AND PHYSICAL P↗
DOE OSTI2022

A new algorithm for estimating radioxenon concentrations

A new algorithm (Xcounts) is introduced for estimating the activity concentrations of the xenon isotopes 131m Xe, 133m Xe, 133 Xe, and 135 Xe using beta-gamma coincidence data. The algorithm simultaneously estimates the decay counts associated with the four xenon isotopes, background, and radon in contrast to the net-counts method that uses sequential residual removal to account for background and interreferences. Calibration data for background counts are determined from gas-background measurements and simulation. In Xcounts, the false positive count rates for 131m Xe and 133m Xe are lower than the false positive rates for 133 Xe and 135 Xe. This algorithm appears to reliably detect the metastable isotopes at lower activity levels than the net-counts method and have similar performance for the other isotopes.

46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND ↗
DOE OSTI2020

Evaluation of Engineered Form MOFs CaSDB and HKUST-1

Idaho National Laboratory (INL) and Pacific Northwest National Laboratory (PNNL) have studied different sorbents for the purpose of separating krypton (Kr) and xenon (Xe). PNNL has researched various metal-organic frameworks (MOFs) that have characteristics theoretically suitable for the separation. Based on computational analysis, PNNL chose Calcium–4,4’–sulfonyl dibenzoate (CaSDB) and Hong Kong University of Science and Technology MOF1 (HKUST–1). The raw MOFs are supplied in a powder form and must be incorporated into a robust engineered form to be viable for gas separation. In 2016, PNNL produced an engineered form of CaSDB by compressing and grinding the raw MOF material. This form was sent to INL for adsorption testing. Gentle mechanical agitation of the compressed form produced a large amount of powder, resulting in the conclusion that the form was not viable for the application. In 2019, INL successfully produced two engineered forms, CaSDB–EF1 and HKUST–EF2, by incorporating the active MOF powders into a polyacrylonitrile (PAN) binder. PNNL also produced two engineered forms, CaSDB–10pmma and HKUST–10pmma, by using polymethyl methacrylate (PMMA) as a binder. Surface area analysis indicated that the forms could be viable for separations in which the CaSDB–EF1 retained 84% of the raw CaSDB surface area and CaSDB–10pmma retained 48%. HKUST–EF2 retained all the raw HKUST–1 surface area, whereas HKUST–10pmma retained only 28%. Mechanical stability testing demonstrated that the PMMA forms formed a fine powder whereas, the PAN forms did not. In general, adsorption testing showed that CaSDB–10pmma had a lower Xe breakthrough capacity than CaSDB–EF1, but a higher saturation capacity at both room temperature and at 253 K. The CaSDB MOF was intended to be used as a room temperature sorbent to capture Xe. However, both CaSDB engineered forms displayed relatively short initial break through times. Reduced temperature increased the Xe capacity of both engineered forms. HKUST–1 was expected to be effective only at sub-zero temperatures. At 195 K, HKUST–10pmma had an initial Xe breakthrough capacity of 119 mmol/ kg, compared to HKUST–EF2 at 339 mmol/ kg. The saturation capacities were 275 and 383 mmol/ kg, respectively. HKUST–10ppm also had a lower Kr capacity of 1.7 mmol/kg, whereas the HKUST–EF had a Kr capacity of 3 mmol/ kg. Test results indicate that the PAN engineered forms are a more suitable choice for the complete separation of Xe and Kr, due to the increase in initial breakthrough capacity. CaSDB allows rapid breakthrough of Kr and Xe regardless of the type of engineered form. At 253 K, it is more viable, but is still not the most effective sorbent. HKUST–EF2 demonstrated viability for Xe capture at 195 K, which may merit further study, however it may be cost prohibitive.

11 - NUCLEAR FUEL CYCLE AND FUEL MATERIALS↗