Howard L. Hall

Development of synthetic nuclear melt glass for forensic analysis

A method for producing synthetic debris similar to the melt glass produced by nuclear surface testing is demonstrated. Melt glass from the first nuclear weapon test (commonly referred to as trinitite) is used as the benchmark for this study. These surrogates can be used to simulate a variety of scenarios and will serve as a tool for developing and validating forensic analysis methods.

Fukushima Daiichi: Implications for carbon‐free energy, nuclear nonproliferation, and community resilience

Implications of the nuclear power plant accidents at Fukushima Daiichi are explored in this commentary. In addition to questions of nuclear reactor regulatory standards, broader implications on noncarbon-emitting energy production, nuclear nonproliferation objectives, and community resilience and emergency response against catastrophic events are explored.

Compositional planning for development of synthetic urban nuclear melt glass

A method is developed for predicting and formulating realistic synthetic post-detonation debris relevant to a nuclear surface detonation in arbitrary urban settings. Using these methods guides the development of synthetic debris that serves as a tool for developing and validating novel rapid forensic analysis methods. In order to accurately fabricate realistic homogenous surrogate material, the method incorporates regional soil compositions, land use data, and vehicle contributions to the urban environment.

Thermodynamic analysis of volatile organometallic fission products.

The ability to perform rapid separations in a post nuclear weapon detonation scenario is an important aspect of national security. In the past, separations of fission products have been performed using solvent extraction, precipitation, etc. The focus of this work is to explore the feasibility of using thermochromatography, a technique largely employed in superheavy element chemistry, to expedite the separation of fission products from fuel components. A series of fission product complexes were synthesized and the thermodynamic parameters were measured using TGA/DSC methods. Once measured, these parameters were used to predict their retention times using thermochromatography.

Gas-phase detection of solid-state fission product complexes for post-detonation nuclear forensic analysis

This study presents the first known detection of fission products commonly found in post-detonation nuclear debris samples using solid sample introduction and a uniquely coupled gas chromatography inductively-coupled plasma time-of-flight mass spectrometer. Rare earth oxides were chemically altered to incorporate a ligand that enhances the volatility of the samples. These samples were injected (as solids) into the aforementioned instrument and detected for the first time. Repeatable results indicate the validity of the methodology, and this capability, when refined, will prove to be a valuable asset for rapid post-detonation nuclear forensic analysis.

Characterization and thermogravimetric analysis of lanthanide hexafluoroacetylacetone chelates

This work reports the thermodynamic characterizations of organometallic species as a vehicle for the rapid separation of volatile nuclear fission products via gas chromatography due to differences in adsorption enthalpy. Because adsorption and sublimation thermodynamics are linearly correlated, there is considerable motivation to determine sublimation enthalpies. A method of isothermal thermogravimetric analysis, TGA-MS and melting point analysis are employed on thirteen lanthanide 1,1,1,5,5,5-hexafluoroacetylacetone complexes to determine sublimation enthalpies. An empirical correlation is used to estimate adsorption enthalpies of lanthanide complexes on a quartz column from the sublimation data. Additionally, four chelates are characterized by SC-XRD, elemental analysis, FTIR and NMR.

Review of current nuclear fallout codes

The importance of developing a robust nuclear forensics program to combat the illicit use of nuclear material that may be used as an improvised nuclear device is widely accepted. In order to decrease the threat to public safety and improve governmental response, government agencies have developed fallout-analysis codes to predict the fallout particle size, dose, and dispersion and dispersion following a detonation. This paper will review the different codes that have been developed for predicting fallout from both chemical and nuclear weapons. This will decrease the response time required for the government to respond to the event.

A comparison of gamma spectra from trinitite versus irradiated synthetic nuclear melt glass

The development of realistic nuclear melt glass surrogates is important to the nuclear forensics community in order to establish analytical protocols for post-detonation analysis. In addition to creating surrogates that are accurate with regard to physical morphology and chemical composition, it is important to develop surrogates that also have similar radiological characteristics. A synthetic melt glass sample was irradiated at the High-Flux Isotope Reactor at Oak Ridge National Laboratory. This sample was counted twice using a semiconductor radiation detector to capture both fission-product signatures as well as those from neutron activation. A qualitative and quantitative analysis was performed to make recommendations for the next irradiation campaign.

Modern Advancements in Post-Detonation Nuclear Forensic Analysis

Deterring nuclear terrorism is a critical national asset to support the preclusion of non-state actors from initiating a nuclear attack on the United States. Successful attribution of a detonated nuclear weapon, which includes locating the source of the radiological materials used in the weapon, allows for timely responsive measures that prove essential in the period following a nuclear event. In conjunction with intelligence and law enforcement evidence, the technical nuclear forensics (TNF) post-detonation community supports this mission through the development and advancement of expertise to characterize weapon debris through a rapid, accurate, and detailed approach. Though the TNF field is young, numerous strides have been made in recent years toward a more robust characterization capability. This work presents modern advancements in post-detonation expertise over the last ten years and demonstrates the need for continued extensive research in this field.

Ion exchange of alkali metal cations with an inorganic resin

ABSTRACT A comparison of the ion exchange properties of the inorganic resin Isolute SCX-2 with alkali metal cations, including francium, to the organic Dowex 50X8 resin is presented. The purpose of this study was to investigate the ion exchange properties of the alkali metal cations with a resin containing a less hydrophobic backbone structure. It was found that the less hydrophobic Isolute SCX-2 resin had a smaller range of values for the distribution coefficients when exchanged with the alkali metals than Dowex 50X8.