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DOE OSTI2025

The Advanced Dimensional Depletion for Engineering of Reactors (ADDER) Software for Depletion and Fuel Management

The Advanced Dimensional Depletion for Engineering of Reactors (ADDER) software is being developed in the Research and Test Reactor (RTR) Program at Argonne National Laboratory to meet the reactor design and analysis needs of the Conversion Program. ADDER is a flexible tool that (1) provides a depletion capability through coupling external neutronics codes with a built-in CRAM solver or external depletion code and (2) provides a user-friendly interface to perform fuel management and criticality search operations. The ADDER software is a Python 3 application written using modern software development practices subject to a compliant implementation of NQA-1 and applicable Department of Energy software quality assurance standards. This report is the user guide for the software release referred to as ADDER v1.1.0. The motivation for a software to have flexible capabilities that ADDER possesses is the need to support a wide variety of geometries that are commonly required in analysis of research and test reactors. These reactors can have complex fuel, experiment, or control material shuffling patterns that persist over several years with many fuel management and partial refueling intervals. The scale of fuel management analysis can require tracking of an inventory that is multiple times the core loading. Many reactors, both power and non-power reactors of various types, will find the features of ADDER useful to facilitate key tasks that a fuel or core design engineer must perform with the convenience of concise input and validated functionality.

22 GENERAL STUDIES OF NUCLEAR REACTORS↗

DOE OSTI2025

The Advanced Dimensional Depletion for Engineering of Reactors (ADDER) Software for Depletion and Fuel Management

22 GENERAL STUDIES OF NUCLEAR REACTORS↗

NASA NTRS1985

Simulations and observations of plasma depletion, ion composition, and airglow emissions in two auroral ionospheric depletion experiments

Observations of plasma depletion, ion composition modification, and airglow emissions in the Waterhole experiments are presented. The detailed ion chemistry and airglow emission processes related to the ionospheric hole formation in the experiment are examined, and observations are compared with computer simulation results. The latter indicate that the overall depletion rates in different parts of the depletion region are governed by different parameters.

Yau, A. W.↗

NASA NTRS1989

The 1988 Antarctic ozone depletion - Comparison with previous year depletions

The 1988 spring Antarctic ozone depletion was observed by TOMS to be substantially smaller than in recent years. The minimum polar total ozone values declined only 15 percent during September 1988, compared to nearly 50 percent during September 1987. At southern midlatitudes, exceptionally high total ozone values were recorded beginning in July 1988. The total integrated southern hemispheric ozone increased rapidly during the Austral spring, approaching 1980 levels during October. The high midlatitude total ozone values were associated with a substantial increase in eddy activity as indicated by the standard deviation in total ozone in the zonal band 30-60 deg S. Mechanisms through which the increased midlatitude eddy activity could disrupt the formation of the Antarctic ozone hole are briefly discussed.

Schoeberl, Mark R.↗

NASA NTRS1994

Interaction of chronic reatine depletion and muscle unloading effects on postural and locomotor muscles

In this study, creatine depletion was induced separately and in combination with non-weight-bearing activity to determine if the response to lowering this metabolite would counter the MHC transitions expected from non-weight-bearing. Creatine depletion was induced by feeding rats a diet supplemented with the creatine analogue beta-guanidinopropionic acid (beta-GPA). Animals were fed a diet containing the creatine analogue for 68 days. Hindlimb non-weight-bearing in BS and NS animals was accomplished by tail suspension for the final 30 days of this period. Beta-GPA feeding lowered the creatine content of muscles sampled by 65%. Creatine depletion resulted in a 16% increase in citrate synthase activity in the soleus (SOL) and a 24% increase in the plantaris (PLN). In two postural muscles, the SOL and vastus intermedius (VI), tail suspension resulted in large decreases in the type I MHC expression and increases in type IIx and IIb MHCs. In two locomotor muscles, the PLN and medial gastrocnemius, type I MHC declined and type IIb increased with suspension. Creatine depletion did not prevent the suspension-induced decline in type I MHC in any of these muscles. The increase in type IIb MHC was either prevented or reduced by creatine depletion before and during suspension in the SOL, VI, and PLN. Creatine depletion alone resulted in small increases in type I and IIa MHCs in the two locomotor muscles, but it had no effect on the MHC profile of the postural muscles studied. These results indicate that the mechanical signal generated by the hindlimb non-weight-bearing state dominated over the metabolic stimulus of creatine depletion with respect to the primary adaptation involving a reduction in type I MHC.

Adams, Gregory R.↗

DOE OSTI2026

Integration of Online Cross-Section Generation Capability with Depletion and Transient Solvers in Griffin

Griffin is a Multiphysics Object-Oriented Simulation Environment (MOOSE)-based reactor multiphysics analysis application jointly developed by Argonne and Idaho National Laboratories under the DOENE Nuclear Energy Advanced Modeling and Simulation (NEAMS) program. In FY25, an online crosssection generation capability based on the Self-Shielding Application Programming Interface (SSAPI) was demonstrated for TRISO-fueled reactor problems under steady-state conditions. This fiscal year, that capability was extended to support depletion and transient multiphysics calculations, enabling high-fidelity analyses that generate self-shielded cross sections on the fly from the actual evolving composition and temperature states rather than from pre-tabulated libraries. For depletion, a two-way coupling was established in which SSAPI computes compact-averaged self-shielded cross sections that the depletion solver then uses to advance the Bateman equations, with the updated compositions returned to SSAPI at each step; the depletion module was refactored to support both library-based and SSAPI-based cross sections, and additional logic was added to track daughter isotopes and to exclude minor isotopes for efficiency. For transient analysis, the SSAPI multigroup library was extended with the kinetics data required for time-dependent calculations, the Improved Quasi-Static (IQS) scheme was coupled with SSAPI, and several supporting capabilities were implemented, including a self-shielding treatment that lets control rods and drums move within a self-shielded model, which had previously been impossible and had ruled out rod- and drum-movement transients with on-the-fly cross sections altogether, a new mixing scheme for delayed-neutron precursor decay constants, a checkpoint-based restart workflow, and performance improvements such as pointwise cross-section interpolation and the bypassing of unnecessary Dancoff factor calculations. The implemented capabilities were verified against Serpent Monte Carlo solutions. For depletion, a prismatic pin-cell problem based on a Next Generation Nuclear Plant (NGNP) Very High Temperature Reactor benchmark showed excellent agreement, with eigenvalue differences within 200 pcm over the entire burnup range (up to 140 MWD/kgU) and fission-product and actinide inventories agreeing to within 0.8% and 2.5%, respectively; a heat-pipe microreactor assembly problem with a much higher fuel loading confirmed the same behavior and quantified the bias introduced when the multigroup equivalence effect is neglected. For transient analysis, a pin-cell problem with a step reactivity insertion and temperature feedback reproduced the analytically expected asymptotic power and showed close agreement between the direct and IQS solutions, and a two-dimensional microreactor core problem with control-drum rotation exercised the new moving-drum self-shielding treatment and demonstrated successful coupling of the online crosssection generation with both the direct and IQS transient methods. The capability was further exercised on a full-core pebble-bed problem, in which Griffin was coupled with the System Analysis Module (SAM) to simulate load-following operation of the gPBR with the Doppler feedback resolved at the TRISO fuel kernel temperature. These developments in Griffin provide a convenient, high-fidelity approach to cross-section generation for advanced thermal reactors with geometrically complex and highly heterogeneous configurations, including TRISO-fueled prismatic and pebble-bed systems, and support steady-state, depletion, and transient multiphysics calculations. They also enable self-shielded cross sections to be evaluated directly at the actual coupled state of the system, thereby establishing a foundation for high-fidelity, fully coupled multiphysics analysis of advanced reactors

Park, H.↗

NASA NTRS1980

Interstellar depletions and far-ultraviolet extinction in the Rho Ophiuchi cloud

Copernicus ultraviolet data on six stars embedded in the well-studied Rho Ophiuchi cloud complex have been analyzed for interstellar abundances, densities, and far-ultraviolet extinction parameters, in an effort to determine how interstellar depletions depend on physical conditions. While there are variations within the cloud in the overall depletions, the pattern of depletions from element to element is constant for all six lines of sight. A picture is suggested in which the cloud core has a small velocity dispersion or is either so strongly depleted or so dense (hence not ionized) that the lines of first ions of heavy elements do not arise there, but rather form in a less-dense or less-depleted outer region. The cloud as a whole has substantial depletions, average to low far-ultraviolet extinction, and a low ratio of molecular to atomic hydrogen.

Snow, T. P., Jr.↗

NASA NTRS1982

Coordinated airborne and satellite measurements of equatorial plasma depletions

A series of experiments conducted in December 1979 to investigate the structure of plasma depletions in the low latitude, nighttime ionosphere is discussed. Density biteouts of about one order of magnitude in the dominant ion, O(+), are mapped to lower altitudes along magnetic field lines for comparison with 6300-A and 7774-A O I airglow depletions. Owing to the different airglow production mechanisms (dissociative recombination of O2(+) for 6300 A and radiative recombination of O(+) for 7774 A), the 6300-A depletions reflect plasma depletions near the bottomside of the F layer, while those at 7774 A are located near the peak of the layer. The O(+) biteouts map directly into the 7774-A airglow depletions in the same hemisphere and also when traced into the opposite hemisphere, which suggests magnetic flux tube alignment over north-south distances of approximately 2220 km. The 6300-A (bottomside) depletions are found to be wider in longitude than the 7774-A (F-peak) depeletions near the equatorward edge of the Appleton anomaly.

Weber, E. J.↗

NASA NTRS1984

Interstellar abundances and depletions inferred from observations of neutral atoms

Data on neutral atomic species are analyzed for the purpose of inferring relative elemental abundances and depletions in diffuse cloud cores, where it is assumed that densities are enhanced in comparison with mean densities over integrated lines of sight. Column densities of neutral atoms are compared to yield relative column densities of singly ionized species, which are assumed dominant in cloud cores. This paper incorporates a survey of literature data on neutral atomic abundances with the result that no systematic enhancement in the depletions of calcium or iron in cloud cores is found, except for zeta Ophiuchi. This may imply that depletions are not influenced by density, but other data argue against this interpretation. It is concluded either that in general all elements are depleted together in dense regions so that their relative abundances remain constant, or that typical diffuse clouds do not have significant cores, but instead are reasonably homogeneous. The data show a probable correlation between cloud-core depletion and hydrogen-molecular fraction, supporting the assumption that overall depletions are a function of density.

Snow, T. P.↗

NASA NTRS1988

Are relative depletions altered inside diffuse clouds?

The data of Jenkins, Savage, and Spitzer (1986) were used to analyze interstellar abundances and depletions of Fe, P, Mg, and Mn toward 37 stars, spanning nearly 1.0 (dex) in mean line-of-sight depletion. It was found that the depletions of these elements are linearly correlated and do not show evidence of differences in the rates of depletion or sputtering from one element to another. For a given level of overall depletion, the sightline-to-sightline rms variance in the depletion for each of these elements was less than 0.16 (dex), which is significantly smaller than is the element-to-element variance. The results suggest that, for most diffuse lines of sight, the relative abundances of these elements are set early in the lifetime of the grains and are not altered significantly thereafter.

Joseph, Charles L.↗

NASA NTRS1992

Evolutionary models of halo stars with rotation. II - Effects of metallicity on lithium depletion, and possible implications for the primordial lithium abundance

Models of metal-poor stars with rotation were computed and their lithium depletion was compared with observations of halo stars. The models that have turn-off ages compatible with the observations have a nearly flat Li-T(eff) relationship in the region of the Spite lithium 'plateau'. Depending on the initial angular momentum, the models have a depletion factor ranging between a factor of 5 and a factor of 10 at fixed T(eff), implying a maximum initial lithium abundance of 3.1. Both the dispersion and the overall depletion factor are much smaller for metal-poor models than for solar metallicity ones. The factors that determine lithium depletion in rotational models are discussed and the different depletion patterns in solar metallicity and metal-poor models are traced to differences in their structure and evolution. The dependence of the lithium depletion on age, mass, initial angular momentum, and metallicity is also discussed. The dispersion predicted from these models is not inconsistent with the observations.

Pinsonneault, M. H.↗

NASA NTRS1995

Gas-phase chemistry in dense interstellar clouds including grain surface molecular depletion and desorption

We present time-dependent models of the chemical evolution of molecular clouds which include depletion of atoms and molecules onto grain surfaces and desorption, as well as gas-phase interactions. We have included three mechanisms to remove species from the grain mantles: thermal evaporation, cosmic-ray-induced heating, and photodesorption. A wide range of parameter space has been explored to examine the abundance of species present both on the grain mantles and in the gas phase as a function of both position in the cloud (visual extinction) and of evolutionary state (time). The dominant mechanism that removes molecules from the grain mantles is cosmic-ray desorption. At times greater than the depletion timescale, the abundances of some simple species agree with abundances observed in the cold dark cloud TMC-1. Even though cosmic-ray desorption preserves the gas-phase chemistry at late times, molecules do show significant depletions from the gas phase. Examination of the dependence of depletion as a function of density shows that when the density increases from 10(exp 3)/cc to 10(exp 5)/cc several species including HCO(+), HCN, and CN show gas-phase abundance reductions of over an order of magnitude. The CO: H2O ratio in the grain mantles for our standard model is on the order of 10:1, in reasonable agreement with observations of nonpolar CO ice features in rho Ophiuchus and Serpens. We have also examined the interdependence of CO depletion with the space density of molecular hydrogen and binding energy to the grain surface. We find that the observed depletion of CO in Taurus in inconsistent with CO bonding in an H2O rich mantle, in agreement with observations. We suggest that if interstellar grains consist of an outer layer of CO ice, then the binding energies for many species to the grain mantle may be lower than commonly used, and a significant portion of molecular material may be maintained in the gas phase.

Bergin, E. A.↗

NASA NTRS1995

Age dependence of myosin heavy chain transitions induced by creatine depletion in rat skeletal muscle

This study was designed to test the hypothesis that myosin heavy chain (MHC) plasticity resulting from creatine depletion is an age-dependent process. At weaning (age 28 days), rat pups were placed on either standard rat chow (normal diet juvenile group) or the same chow supplemented with 1% wt/wt of the creatine analogue beta-guanidinopropionic acid (creatine depletion juvenile (CDJ) group). Two groups of adult rats (age approximately 8 wk) were placed on the same diet regimens (normal diet adult and creatine depletion adult (CDA) groups). After 40 days (CDJ and normal diet juvenile groups) and 60 days (CDA and normal diet adult groups), animals were killed and several skeletal muscles were removed for analysis of creatine content or MHC ditribution. In the CDJ group, creatine depletion (78%) was accompanied by significant shifts toward expression of slower MHC isoforms in two slow and three fast skeletal muscles. In contrast, creatine depletion in adult animals did not result in similar shifts toward slow MHC isoform expression in either muscle type. The results of this study indicate that there is a differential effect of creatine depletion on MHC tranitions that appears to be age dependent. These results strongly suggest that investigators contemplating experimental designs involving the use of the creatine analogue beta-guanidinopropionic acid should consider the age of the animals to be used.

Adams, Gregory R.↗

NASA NTRS2002

Constraining the Material that Formed the Moon: The Origin of Lunar V, CR, and MN Depletions

The mantles of the Earth and Moon are similarly depleted in V, Cr, and Mn relative to chondritic values. Core formation deep within the Earth was suggested by as the origin of the depletions. Following Earth's core formation, the Moon was proposed to have inherited its mantle from the depleted mantle of the Earth by a giant impact event. This theory implied the Moon was primarily composed of material from the Earth's mantle. Recent systematic metal-silicate experiments of V, Cr, and Mn evaluated the behavior of these elements during different core formation scenarios. The study found that the V, Cr, and Mn depletions in the Earth could indeed be explained by core formation. The conditions of core formation necessary to deplete V, Cr, and Mn in the Earth's mantle were consistent with the deep magma ocean proposed to account for the Earth's mantle abundances of Ni and Co. Using the parameterizations of for the metal-silicate partition coefficients (D) of V, Cr, and Mn, we investigate here the conditions needed to match the depletions in the silicate Moon and determine if such conditions could have been present on the giant impactor.

Chabot, N. L.↗

DOE OSTI2026

Application of Fuel Depletion Chain Simplification to Experiment Analysis in the Advanced Test Reactor

An irradiation experiment analysis can be informed by high-fidelity reactor engineering depletion results, but this comes at a computational cost. Applying depletion chain simplification to the advanced test reactor driver fuel before performing experiment depletions permits their programmatic parameters to be calculated faster, with a small penalty to accuracy. Here, this work contrasts the results of two irradiation experiments with different neutronic characteristics. Overall, the simplified nuclide library produced using a simple one-group microscopic cross-section library for a pressurized water reactor in the depletion chain simplification process performed comparably in terms of accuracy and runtime to the simplified nuclide library produced using a three-group microscopic cross-section library generated specifically for the advanced test reactor experiments being modeled. This is attributed to the additional nuclides and transmutation pathways preserved in the one-group cross-section library, which has data for 297 nuclides, compared to the three-group cross-section library, which has data for 217 nuclides. This indicates that a cross-section library with more nuclides is better than a cross-section library with fewer nuclides for the depletion chain simplification process, even if the cross-section library with fewer nuclides better represents the flux spectrum of the system being considered.

11 - NUCLEAR FUEL CYCLE AND FUEL MATERIALS↗

NASA NTRS1973

Measured and calculated fast neutron spectra in a depleted uranium and lithium hydride shielded reactor

Measurements of MeV neutron were made at the surface of a lithium hydride and depleted uranium shielded reactor. Four shield configurations were considered: these were assembled progressively with cylindrical shells of 5-centimeter-thick depleted uranium, 13-centimeter-thick lithium hydride, 5-centimeter-thick depleted uranium, 13-centimeter-thick lithium hydride, 5-centimeter-thick depleted uranium, and 3-centimeter-thick depleted uranium. Measurements were made with a NE-218 scintillation spectrometer; proton pulse height distributions were differentiated to obtain neutron spectra. Calculations were made using the two-dimensional discrete ordinates code DOT and ENDF/B (version 3) cross sections. Good agreement between measured and calculated spectral shape was observed. Absolute measured and calculated fluxes were within 50 percent of one another; observed discrepancies in absolute flux may be due to cross section errors.

Lahti, G. P.↗

NASA NTRS1982

Seasonal dependence of the distribution of large-scale plasma depletions in the low-latitude F region

From several years of Atmosphere Explorer data, it is shown that large-scale plasma density depletions (horizontal scale greater than 1000km) in the nocturnal F region occur mainly during the first half of the night. The geomagnetic latitude of these depletions depends on season: at solstice periods the occurrence is mainly in the summer hemisphere and at equinoxes mainly on the geomagnetic equator. Large-scale depletions occur most often at longitudes characterized by a large magnetic declination. The large-scale plasma depletions are interpreted to be a consequence of imposed upward drift which raises the F region above the satellite trajectory. This interpretation is tested by calculating the vertical ion drift velocity imposed by zonal and meridional winds and electrostatic fields, with allowance for the effects of diffusion. The calculations reveal a correspondence between the locations of maxima in the calculated vertical ion drift velocity and the large-scale plasma depletions.

Dachev, T. P.↗

NASA NTRS1985

Ozone depletion during solar proton events in solar cycle 21

Ozone profile data from the Solar Backscattered Ultraviolet Instrument on Nimbus 7 from 1979 to the present and clear cases of ozone destruction associated with five sudden proton events (SPEs) on June 7, 1979, August 21, 1979, October 13-14, 1981, July 13, 1982, and December 8, 1982 are found. During the SPE on July 13, 1982, the largest of this solar cycle, no depletion at all at 45 km is observed, but there is a 15 percent ozone depletion at 50 km increasing to 27 percent at 55 km, all at a solar zenith angle of 85 deg. A strong variation of the observed depletion with solar zenith angle is found, with maximum depletion occurring at the largest zenith angles (near 85 deg) decreasing to near zero for angles below about 70 deg. The observed depletion is short lived, disappearing within hours of the end of the SPE.

Mcpeters, R. D.↗