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DOE OSTI2011

Application of different nuclides in retrospective dosimetry

The activities of nuclides produced via the neutron irradiation of reactor pressure vessel (RPV) steel are used to validate respective fluence calculations. Niobium, nickel, and technetium isotopes from RPV trepans of the decommissioned NPP Greifswald (VVER-440) have been analyzed. The activities were determined by TRAMO (Monte-Carlo) fluence calculations, newly applying 640 neutron-energy groups and ENDF/B7 data. Relative to earlier results, fluences up to 20% higher have been computed, leading to somewhat better agreement between measurement and calculation, particularly in the case of Tc-99. (authors)

21 SPECIFIC NUCLEAR REACTORS AND ASSOCIATED PLANTS↗

DOE OSTI2024

Simple separation of technetium from molybdenum for tracer isotope production

A procedure for the separation of technetium isotopes from bulk molybdenum was developed in nitric acid media. After irradiation of nat Mo foils, and dissolution in H 2 O 2 , the solution is acidified to 2 M HNO 3 , and anion exchange resin is used to separate technetium from molybdenum. The procedure is simple, requiring only basic laboratory equipment and, with a two-column separation, the technetium yield is high (~ 85%) with extremely high purity (< 0.1 ppm nat Mo). In conclusion, this is ideally suited for laboratory production of technetium tracer isotopes, particularly 95m Tc.

38 RADIATION CHEMISTRY, RADIOCHEMISTRY, AND NUCLEA↗

DOE OSTI2011

Nuclear Data Sheets for A = 93

Nuclear structure data pertaining to all nuclei with mass number A=93 (Se, Br, Kr, Rb, Sr, Y, Zr, Nb, Mo, Tc, Ru, Rh, Pd, Ag) have been compiled and evaluated and incorporated into the ENSDF data file. This publication for A=93 supersedes the previous publication by C.M. Baglin, Nuclear Data Sheets80, 1 (1997) (literature cutoff date November 1996) and subsequent revisions by C.M. Baglin of the ENSDF files for 93Br and {sup 93}Kr (literature cutoff 26 February 2001) and for {sup 93}Rh (literature cutoff 27 February 2001); it includes all data available prior to 15 December 2010. Significant changes since prior evaluations include the following: 2010Hw03 identified several high-spin states in {sup 93}Kr in {sup 252}Cf SF decay; in addition to the many low-spin levels already known in {sup 93}Rb from {beta}{sup -} decay, several higher-spin states have now been identified in a {sup 252}Cf SF decay study (2009Hw03); this SF decay has also been used to identify additional states in {sup 93}Sr (2003Hw01) and the {sup 238}U({sup 82}Se,X{gamma}) reaction (2007Bu35) has provided new information on {sup 93}Y. (HI,xn{gamma}) reaction studies have expanded our knowledge of the structure of {sup 93}Zr (2002Fo03, 2005Pa48), {sup 93}Nb (2007Wa45), {sup 93}Mo (2005Fu01), {sup 93}Tc (2003Ha22) and {sup 93}Pd (2004So04,2004Ru02). Considerable information on {sup 93}Nb was provided by a (p,2n{gamma}) study (2010Or01, 2006Or09, 2007Or01). The level schemes of {sup 93}Ru, {sup 93}Rh and {sup 93}Pd have undergone the most extensive revision thanks to studies of {sup 93}Rh {epsilon} decay (2004De40), {sup 94}Ag {epsilon}p decay (2004Mu30) and {sup 94}Ag p decay (2005Mu15, 2005Mu30), respectively. The half-life of the Zr member of this chain is of particular interest because of {sup 93}Zr's large contribution to long-term activity of nuclear reactor waste and also due to its potential as a supernova chronometer. During 2010, two new well-documented measurements of T{sub 1/2}({sup 93}Zr) were published (2010Ya01 and 2010Ca01); one agrees well with an earlier, undocumented measurement but, unfortunately, the other is many standard deviations lower for reasons which are not immediately apparent.

73 NUCLEAR PHYSICS AND RADIATION PHYSICS↗

DOE OSTI2019

Diagnostic value of stress thallium-201/rest technetium-99m-sestamibi sequential dual isotope high-speed myocardial perfusion imaging for the detection of haemodynamically relevant coronary artery stenosis

Background: The aim of this study was to determine the diagnostic accuracy of stress thallium-201/rest technetium-99m-sestamibi sequential dual-isotope high-speed myocardial perfusion imaging (DI-HS-MPI) against invasively determined fractional flow reserve (FFR). Methods: Fifty-four consecutive patients prospectively underwent DI-HS-MPI before invasive coronary angiography. Perfusion was scored visually by summed stress score on a patient and coronary territory basis. Significant coronary artery disease (CAD) was defined by the presence of ≥ 90% stenosis/occlusion or fractional flow reserve ≤ 0.80 for coronary stenosis ≥ 50%. Results: FFR was measured in 69 of 162 coronary vessels, with 1.28 ± 0.56 vessels assessed/patient. Sensitivity, specificity, and diagnostic accuracy of MPI for the detection of significant CAD were 92.8%, 69.2%, and 81.4%, on a patient basis, and 83.7%, 90.4%, and 88.8% by coronary territory. Conclusions: DI-HS-MPI accurately detects functionally significant CAD as defined by using FFR.

62 RADIOLOGY AND NUCLEAR MEDICINE↗

DOE OSTI2023

Mo-99 Concentration and processing by Solvent Extraction and Ion Exchange

Normally derived from its transient-equilibrium parent molybdenum-99 ( 99 Mo) (t½ = 66 h), the short-lived isotope technetium-99m ( 99m Tc) (t ½ = 6.0 h) is the most widely used medical isotope in diagnostic imaging today. The National Nuclear Security Administration’s (NNSA’s) Material Management and Minimization (M3) program—established under the auspices of the American Medical Isotope Production Act—has been tasked with facilitating the work of domestic 99 Mo suppliers that do not use highly enriched uranium (HEU). Superconducting electron linear accelerators that employ high-Z converter targets can generate bremsstrahlung photons and neutron fluxes that can induce photonuclear reactions and uranium (U) fission. Argonne, in collaboration with industrial partners, has been developing the process chemistry for superconducting linear accelerator (LINAC)-irradiated triuranium octoxide (U 3 O 8 ) targets to produce 99 Mo. In short, the process involves dissolving the irradiated targets in nitric acid, which simultaneously releases valuable fission products (xenon and iodine). After adjusting the acid concentration, producers process the feed using tri-n-butyl phosphate (TBP), then mix the raffinate derived from this extraction cycle with a phosphinic acid such as Cyanex 272 or di(2-ethylhexyl) phosphoric acid (HDEHP), which is selective for Mo (molybdenum liquid liquid extraction [MoLLE]). In the next step, a concentration column comprising an anion exchange platform is used to decontaminate the remaining fission products, generating a pure 99 Mo stream in sodium hydroxide (NaOH)/sodium chloride (NaCl).

38 RADIATION CHEMISTRY, RADIOCHEMISTRY, AND NUCLEA↗

DOE OSTI2020

Impact of UV-light and pH on the Fate of Tc, I, and U in Wetlands at Savannah River Site - 20230

The Savannah River Site (SRS) is one of the major nuclear facilities owned by the U.S Department of Energy. During the Cold War, these facilities produced large amounts of radioactive and hazardous waste. On site, three unlined seepage basins in the F-Area received approximately 1.8 billion gallons of low-level waste containing nitric acid, radionuclides, and dissolved metals due to plutonium and tritium production operations. The acidic nature of the waste created a source of relatively mobile radionuclides below the basins. Radionuclides previously disposed of within the F-Area, including uranium isotopes (U), technetium-99 (Tc-99), and iodine-129 (I-129), are moving with groundwater towards Four Mile Branch Wetland, where they are subsequently upwelling and interacting with natural organic matter (NOM). Many environmental factors including redox conditions, porewater composition, pH, light, and temperature affect the degradation of organic matter as well as interactions with Tc-99, U, and I-129. In particular, the high concentrations of nitrate from the acidic waste may increase the formation of reactive oxygen species (ROS) that impact both degradation of NOM and behavior of contaminants. In the presence of sunlight, I-129, Tc-99, and U speciation and complexation behavior may be affected by ROS and NOM degradation products in addition to the factors generally considered in subsurface systems in the absence of light. This research aims to determine whether the interactions between radionuclides, NOM, and nitrate affect the fate of I-129, Tc-99, and U and which processes are controlling their behavior. Experiments were conducted at variable pH in the presence of NaNO{sub 3} in order to determine the impact of light and pH on NOM degradation and to evaluate the impact on the fate of contaminants of concern. Soil samples high in NOM collected from two sites in the Southeastern United States (Savannah River Site and the Everglades) were studied. Batch experiments were conducted with NOM and the following aqueous contaminants, U, I-129, Tc-99 with exposure to ultraviolet (UV) light in an environmental chamber. This study was conducted in a sterile environment in order to exclude the potential for microbial degradation of organic matter. Results indicated photodegradation of NOM and significant interaction of radionuclides with NOM. (authors)

12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗

DOE OSTI2011

X-Rays Compton Detectors For Biomedical Application

Collimators are usually needed to image sources emitting X-rays that cannot be focused. Alternately, one may employ a Compton Camera (CC) and measure the direction of the incident X-ray by letting it interact with a thin solid, liquid or gaseous material (Tracker) and determine the scattering angle. With respect to collimated cameras, CCs allow higher gamma-ray efficiency in spite of lighter geometry, and may feature comparable spatial resolution. CCs are better when the X-ray energy is high and small setups are required. We review current applications of CCs to Gamma Ray Astronomy and Biomedical systems stressing advantages and drawbacks. As an example, we focus on a particular CC we are developing, which is designed to image small animals administered with marked pharmaceuticals, and assess the bio-distribution and targeting capability of these latter. This camera has to address some requirements: relatively high activity of the imaged objects; detection of gamma-rays of different energies that may range from 140 keV (Tc99m) to 511 keV; presence of gamma and beta radiation with energies up to 2 MeV in case of 188Re. The camera consists of a thin position-sensitive Silicon Drift Detector as Tracker, and a further downstream position-sensitive system employing scintillating crystals and a multi-anode photo-multiplier (Calorimeter). The choice of crystal, pixel size, and detector geometry has been driven by measurements and simulations with the tracking code GEANT4. Spatial resolution, efficiency and scope are discussed.

46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND ↗

DOE OSTI2011

[{sup 13}N] Ammonia Cardiac Program At West Virginia University Health Sciences

Due to the shortage of the more traditional cardiac imagining isotopes, specifically, Technicium-99, the Cardiologists at WVU have had to look to alternative imagining techniques such as PET. This has led to a dramatic increase in the use of [{sup 13}N] Ammonia PET scans at the Health Sciences Center. The patient load has gone from one to two patients one day a week to typically two to three patients, two days a week, with occasional add-on in-house patients; each patient typically requiring two target irradiations. In this paper, we will discuss the process that is being used to meet this increased demand from the production of the isotope through the final result.

62 RADIOLOGY AND NUCLEAR MEDICINE↗

DOE OSTI2011

Mass Measurements of Very Neutron-Deficient Mo and Tc Isotopes and Their Impact on rp Process Nucleosynthesis

The masses of ten proton-rich nuclides, including the N=Z+1 nuclides {sup 85}Mo and {sup 87}Tc, were measured with the Penning trap mass spectrometer SHIPTRAP. Compared to the Atomic Mass Evaluation 2003 a systematic shift of the mass surface by up to 1.6 MeV is observed causing significant abundance changes of the ashes of astrophysical x-ray bursts. Surprisingly low {alpha} separation energies for neutron-deficient Mo and Tc are found, making the formation of a ZrNb cycle in the rp process possible. Such a cycle would impose an upper temperature limit for the synthesis of elements beyond Nb in the rp process.

73 NUCLEAR PHYSICS AND RADIATION PHYSICS↗

DOE OSTI2017

Technetium: The First Radioelement on the Periodic Table

The radioactive nature of technetium is discussed using a combination of introductory nuclear physics concepts and empirical trends observed in the chart of the nuclides and the periodic table of the elements. Trends such as the enhanced stability of nucleon pairs, magic numbers, and Mattauch's rule are described. Here, the concepts of nuclear binding energies and the nuclear shell model are introduced and used to explain the relative stability of radionuclides and, in particular, the isotopes of technetium.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗

DOE OSTI2015

Superconducting state parameters of monovalent and polyvalent amorphous

In the present study deals, we have calculated superconducting state parameter (SSP) like electron-phonon coupling strength λ, coulomb pseudo potential, μ*, transition temperature Tc, isotope effect exponent α and effective interaction strength N{sub 0}V of monovalent (Li), divalent (Zn), trivalent (In) and tetravalent (Pb) amorphous. To carry out this work we have used our newly constructed model pseudo potential to describe electron ion interaction along with three different local field correction functions like Hartree, Taylor and Sarkar et al. The present results are found in good agreement with other available theoretical as well as experimental data.

36 MATERIALS SCIENCE↗

DOE OSTI2014

Contribution of Recently Measured Nuclear Data to Reactor Antineutrino Energy Spectra Predictions

The aim of this work is to study the impact of the inclusion of the recently measured β decay properties of the {sup 102,104,105,106,107}Tc, {sup 105}Mo, and {sup 101}Nb nuclei in the calculation of the antineutrino (anti-ν) energy spectra arising after the fissions of the four main fissile isotopes {sup 235,238}U, and {sup 239,241}Pu in PWRs. These β feeding probabilities, measured using the Total Absorption Technique (TAS) at the JYFL facility of Jyväskylä, have been found to play a major role in the γ component of the decay heat for {sup 239}Pu in the 4-3000 s range. Following the fission product summation method, the calculation was performed using the MCNP Utility Reactor Evolution code (MURE) coupled to the experimental spectra built from β decay properties of the fission products taken from evaluated databases. These latest TAS data are found to have a significant effect on the Pu isotope energy spectra and on the spectrum of {sup 238}U showing the importance of their measurement for a better assessment of the reactor anti-ν energy spectrum, as well as importance for fundamental neutrino physics experiments and neutrino applied physics.

73 NUCLEAR PHYSICS AND RADIATION PHYSICS↗

DOE OSTI2017

Design of a Fission 99 Mo Recovery Process and Implications toward Mo Adsorption Mechanism on Titania and Alumina Sorbents

Molybdenum-99 is a parent of the most widely used medical isotope technetium-99m. Proliferation concerns have prompted development of alternative Mo production methods utilizing low enriched uranium. Alumina and titania sorbents were evaluated for separation of Mo from concentrated uranyl nitrate solutions. System, mass transfer, and isotherm parameters were determined to enable design of Mo separation processes under a wide range of conditions. A model-based approach was utilized to design representative commercial-scale column processes. The designs and parameters were verified with bench-scale experiments. The results are essential for design of Mo separation processes from irradiated uranium solutions, selection of support material and process optimization. Mo uptake studies show that adsorption decreases with increasing concentration of uranyl nitrate; howeveL, examination of Mo adsorption as a function of nitrate ion concentration shows no dependency, indicating that uranium competes with Mo for adsorption sites. These results are consistent with reports indicating that Mo forms inner-sphere complexes with titania and alumina surface groups.

73 NUCLEAR PHYSICS AND RADIATION PHYSICS↗

DOE OSTI2017

Controlling Pu behavior on Titania: Implications for LEU Fission-Based Mo-99 Production

Molybdenum-99 is the parent isotope of the most widely used isotope, technetium-99m, in all diagnostic nuclear medicine procedures. Due to proliferation concerns associated with the use of highly enriched uranium (HEU), the preferred method of fission-based Mo-99 production uses low enriched uranium (LEU) targets. Using LEU versus HEU for Mo-99 production produces similar to 30 times more Pu-239, due to neutron capture on U-238 to produce Np-239, which ultimately decays to Pu-239 (t(1/2) = 24,110 yr). Argonne National Laboratory is supporting a potential US Mo-99 producer in their efforts to produce Mo-99 from an LEU solution. In order to mitigate the generation of large volumes of greater-than-class-C (GTCC) low level waste (Pu-239 concentrations greater than 1 nCi/g), we have focused our efforts on the separation chemistry of Pu and Mo with a titania sorbent in sulfate media. Results from batch and column experiments show that temperature and acid wash concentration can be used to control Pu behavior on titania.

low enriched uranium↗

DOE OSTI2013

Computational analysis of kidney scintigrams

The scintigraphic investigation of normal and pathological kidneys was carried out using specialized gamma-camera device from nuclear medicine hospital department. Technetium 90m isotope with gamma radiation emission, coupled with vector molecules for kidney tissues was introduced into the subject body, its dynamics being recorded as data source for kidney clearance capacity. Two representative data series were investigated, corresponding to healthy and pathological organs respectively. The semi-quantitative tests applied for the comparison of the two distinct medical situations were: the shape of probability distribution histogram, the power spectrum, the auto-correlation function and the Lyapunov exponent. While power spectrum led to similar results in both cases, significant differences were revealed by means of distribution probability, Lyapunov exponent and correlation time, recommending these numerical tests as possible complementary tools in clinical diagnosis.

62 RADIOLOGY AND NUCLEAR MEDICINE↗

DOE OSTI2013

Nuclear Fuel Reprocessing

Reprocessing is essential to closing nuclear fuel cycle. Natural uranium contains only 0.7 percent 235U, the fissile (see glossary for technical terms) isotope that produces most of the fission energy in a nuclear power plant. Prior to being used in commercial nuclear fuel, uranium is typically enriched to 3–5% in 235U. If the enrichment process discards depleted uranium at 0.2 percent 235U, it takes more than seven tonnes of uranium feed to produce one tonne of 4%-enriched uranium. Nuclear fuel discharged at the end of its economic lifetime contains less one percent 235U, but still more than the natural ore. Less than one percent of the uranium that enters the fuel cycle is actually used in a single pass through the reactor. The other naturally occurring isotope, 238U, directly contributes in a minor way to power generation. However, its main role is to transmute into plutoniumby neutron capture and subsequent radioactive decay of unstable uraniumand neptuniumisotopes. 239Pu and 241Pu are fissile isotopes that produce more than 40% of the fission energy in commercially deployed reactors. It is recovery of the plutonium (and to a lesser extent the uranium) for use in recycled nuclear fuel that has been the primary focus of commercial reprocessing. Uraniumtargets irradiated in special purpose reactors are also reprocessed to obtain the fission product 99Mo, the parent isotope of technetium, which is widely used inmedical procedures. Among the fission products, recovery of such expensive metals as platinum and rhodium is technically achievable, but not economically viable in current market and regulatory conditions. During the past 60 years, many different techniques for reprocessing used nuclear fuel have been proposed and tested in the laboratory. However, commercial reprocessing has been implemented along a single line of aqueous solvent extraction technology called plutonium uranium reduction extraction process (PUREX). Similarly, hundreds of types of reactor fuels have been irradiated for different purposes, but the vast majority of commercial fuel is uranium oxide clad in zirconium alloy tubing. As a result, commercial reprocessing plants have relatively narrow technical requirements for used nuclear that is accepted for processing.

11 NUCLEAR FUEL CYCLE AND FUEL MATERIALS↗

DOE OSTI2017

Tc-99 Decontamination From Heat Treated Gaseous Diffusion Membrane -Phase I

12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗

DOE OSTI2017

TC-99 Decontaminant from heat treated gaseous diffusion membrane -Phase I, Part B

Uranium gaseous diffusion cascades represent a significant environmental challenge to dismantle, containerize and dispose as low-level radioactive waste. Baseline technologies rely on manual manipulations involving direct access to technetium-contaminated piping and materials. There is a potential to utilize novel decontamination technologies to remove the technetium and allow for on-site disposal of the very large uranium converters. Technetium entered these gaseous diffusion cascades as a hexafluoride complex in the same fashion as uranium. Technetium, as the isotope Tc-99, is an impurity that follows uranium in the first cycle of the Plutonium and Uranium Extraction (PUREX) process. The technetium speciation or exact form in the gaseous diffusion cascades is not well defined. Several forms of Tc-99 compounds, mostly the fluorinated technetium compounds with varying degrees of volatility have been speculated by the scientific community to be present in these cascades. Therefore, there may be a possibility of using thermal or leaching desorption, which is independent of the technetium oxidation states, to perform an insitu removal of the technetium as a volatile species and trap the radionuclide on sorbent traps which could be disposed as low-level waste. Based on the positive results of the first part of this work1 the use of steam as a thermal decontamination agent was further explored with a second piece of used barrier material from a different location. This new series of tests included exposing more of the material surface to the flow of high temperature steam through the change in the reactor design, subjecting it to alternating periods of stream and vacuum, as well as determining if a lower temperature steam, i.e., 121°C (250°F) would be effective, too. Along with these methods, one other simpler method involving the leaching of the Tc-99 contaminated barrier material with a 1.0 M aqueous solution of ammonium carbonate, with and without sonication, was evaluated.

12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗