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At least 757 records · Page 42

Surface, Water, and Air Biocharacterization (SWAB) Flight Experiment

The determination of risk from infectious disease during spaceflight missions is composed of several factors including both the concentration and characteristics of the microorganisms to which the crew are exposed. Thus, having a good understanding of the microbial ecology aboard spacecraft provides the necessary information to mitigate health risks to the crew. While preventive measures are taken to minimize the presence of pathogens on spacecraft, medically significant organisms have been isolated from both the Mir and International Space Station (ISS). Historically, the method for isolation and identification of microorganisms from spacecraft environmental samples depended upon their growth on culture media. Unfortunately, only a fraction of the organisms may grow on a specific culture medium, potentially omitting those microorganisms whose nutritional and physical requirements for growth are not met. To address this bias in our understanding of the ISS environment, the Surface, Water, and Air Biocharacterization (SWAB) Flight Experiment was designed to investigate and develop monitoring technology to provide better microbial characterization. For the SWAB flight experiment, we hypothesized that environmental analysis using non-culture-based technologies would reveal microorganisms, allergens, and microbial toxins not previously reported in spacecraft, allowing for a more complete health assessment. Key findings during this experiment included: a) Generally, advanced molecular techniques were able to reveal a few organisms not recovered using culture-based methods; however, there is no indication that current monitoring is "missing" any medically significant bacteria or fungi. b) Molecular techniques have tremendous potential for microbial monitoring, however, sample preparation and data analysis present challenges for spaceflight hardware. c) Analytical results indicate that some molecular techniques, such as denaturing gradient gel electrophoresis (DGGE), can be much less sensitive than culture-based methods. d) More sensitive molecular techniques, such as quantitative polymerase chain reaction (QPCR), were able to identify viral DNA from ISS environments, suggesting potential transfer of the organism between crewmembers. In addition, the hardware selected for this experiment represented advances for next-generation sample collection. The advanced nature of this collection hardware was noted, when the Sartorius MD8 Air Port air sampler from the SWAB experiment remained on board ISS at the request of JAXA investigators, who intend to use it in completion of their microbial ecology experiment.

Castro, V. A.↗

Combustion, Complex Fluids, and Fluid Physics Experiments on the ISS

From the very early days of human spaceflight, NASA has been conducting experiments in space to understand the effect of weightlessness on physical and chemically reacting systems. NASA Glenn Research Center (GRC) in Cleveland, Ohio has been at the forefront of this research looking at both fundamental studies in microgravity as well as experiments targeted at reducing the risks to long duration human missions to the moon, Mars, and beyond. In the current International Space Station (ISS) era, we now have an orbiting laboratory that provides the highly desired condition of long-duration microgravity. This allows continuous and interactive research similar to Earth-based laboratories. Because of these capabilities, the ISS is an indispensible laboratory for low gravity research. NASA GRC has been actively involved in developing and operating facilities and experiments on the ISS since the beginning of a permanent human presence on November 2, 2000. As the lead Center for combustion, complex fluids, and fluid physics; GRC has led the successful implementation of the Combustion Integrated Rack (CIR) and the Fluids Integrated Rack (FIR) as well as the continued use of other facilities on the ISS. These facilities have supported combustion experiments in fundamental droplet combustion; fire detection; fire extinguishment; soot phenomena; flame liftoff and stability; and material flammability. The fluids experiments have studied capillary flow; magneto-rheological fluids; colloidal systems; extensional rheology; pool and nucleate boiling phenomena. In this paper, we provide an overview of the experiments conducted on the ISS over the past 12 years.

Motil, Brian↗

Using the Flow-3D General Moving Object Model to Simulate Coupled Liquid Slosh - Container Dynamics on the SPHERES Slosh Experiment: Aboard the International Space Station

The SPHERES Slosh Experiment (SSE) is a free floating experimental platform developed for the acquisition of long duration liquid slosh data aboard the International Space Station (ISS). The data sets collected will be used to benchmark numerical models to aid in the design of rocket and spacecraft propulsion systems. Utilizing two SPHERES Satellites, the experiment will be moved through different maneuvers designed to induce liquid slosh in the experiment's internal tank. The SSE has a total of twenty-four thrusters to move the experiment. In order to design slosh generating maneuvers, a parametric study with three maneuvers types was conducted using the General Moving Object (GMO) model in Flow-30. The three types of maneuvers are a translation maneuver, a rotation maneuver and a combined rotation translation maneuver. The effectiveness of each maneuver to generate slosh is determined by the deviation of the experiment's trajectory as compared to a dry mass trajectory. To fully capture the effect of liquid re-distribution on experiment trajectory, each thruster is modeled as an independent force point in the Flow-3D simulation. This is accomplished by modifying the total number of independent forces in the GMO model from the standard five to twenty-four. Results demonstrate that the most effective slosh generating maneuvers for all motions occurs when SSE thrusters are producing the highest changes in SSE acceleration. The results also demonstrate that several centimeters of trajectory deviation between the dry and slosh cases occur during the maneuvers; while these deviations seem small, they are measureable by SSE instrumentation.

Schulman, Richard↗

Supercritical Water Mixture (SCWM) Experiment in the High Temperature Insert-Reflight (HTI-R)

Current research on supercritical water processes on board the International Space Station (ISS) focuses on salt precipitation and transport in a test cell designed for supercritical water. This study, known as the Supercritical Water Mixture Experiment (SCWM) serves as a precursor experiment for developing a better understanding of inorganic salt precipitation and transport during supercritical water oxidation (SCWO) processes for the eventual application of this technology for waste management and resource reclamation in microgravity conditions. During typical SCWO reactions any inorganic salts present in the reactant stream will precipitate and begin to coat reactor surfaces and control mechanisms (e.g., valves) often severely impacting the systems performance. The SCWM experiment employs a Sample Cell Unit (SCU) filled with an aqueous solution of Na2SO4 0.5-w at the critical density and uses a refurbished High Temperature Insert, which was used in an earlier ISS experiment designed to study pure water at near-critical conditions. The insert, designated as the HTI-Reflight (HTI-R) will be deployed in the DECLIC (Device for the Study of Critical Liquids and Crystallization) Facility on the International Space Station (ISS). Objectives of the study include measurement of the shift in critical temperature due to the presence of the inorganic salt, assessment of the predominant mode of precipitation (i.e., heterogeneously on SCU surfaces or homogeneously in the bulk fluid), determination of the salt morphology including size and shapes of particulate clusters, and the determination of the dominant mode of transport of salt particles in the presence of an imposed temperature gradient. Initial results from the ISS experiments will be presented and compared to findings from laboratory experiments on the ground.

salts↗

NASA Bioculture System: From Experiment Definition to Flight Payload

Starting in 2015, the NASA Bioculture System will be available to the science community to conduct cell biology and microbiology experiments on ISS. The Bioculture System carries ten environmentally independent Cassettes, which house the experiments. The closed loop fluids flow path subsystem in each Cassette provides a perfusion-based method for maintain specimen cultures in a shear-free environment by using a biochamber based on porous hollow fiber bioreactor technology. Each Cassette contains an incubator and separate insulated refrigerator compartment for storage of media, samples, nutrients and additives. The hardware is capable of fully automated or manual specimen culturing and processing, including in-flight experiment initiation, sampling and fixation, up to BSL-2 specimen culturing, and the ability to up to 10 independent cultures in parallel for statistical analysis. The incubation and culturing of specimens in the Bioculture System is a departure from standard laboratory culturing methods. Therefore, it is critical that the PI has an understanding the pre-flight test required for successfully using the Bioculture System to conduct an on-orbit experiment. Overall, the PI will conduct a series of ground tests to define flight experiment and on-orbit implementation requirements, verify biocompatibility, and determine base bioreactor conditions. The ground test processes for the utilization of the Bioculture System, from experiment selection to flight, will be reviewed. Also, pre-flight test schedules and use of COTS ground test equipment (CellMax and FiberCell systems) and the Bioculture System will be discussed.

Bioculture System↗

Orion EFT-1 Catalytic Tile Experiment Overview and Flight Measurements

This paper describes the design and results of a surface catalysis flight experiment flown on the Orion Multipurpose Crew Vehicle during Exploration Flight Test 1 (EFT1). Similar to previous Space Shuttle catalytic tile experiments, the present test consisted of a highly catalytic coating applied to an instrumented TPS tile. However, the present catalytic tile experiment contained significantly more instrumentation in order to better resolve the heating overshoot caused by the change in surface catalytic efficiency at the interface between two distinct materials. In addition to collecting data with unprecedented spatial resolution of the "overshoot" phenomenon, the experiment was also designed to prove if such a catalytic overshoot would be seen in turbulent flow in high enthalpy regimes. A detailed discussion of the results obtained during EFT1 is presented, as well as the challenges associated with data interpretation of this experiment. Results of material testing carried out in support of this flight experiment are also shown. Finally, an inverse heat conduction technique is employed to reconstruct the flight environments at locations upstream and along the catalytic coating. The data and analysis presented in this work will greatly contribute to our understanding of the catalytic "overshoot" phenomenon, and have a significant impact on the design of future spacecraft.

Salazar, Giovanni↗

Observation Platform for Dynamic Biomedical and Biotechnology Experiments Using the International Space Station (ISS) Light Microscopy Module (LMM)

Techshot, Inc., has developed an observation platform for the LMM on the ISS that will enable biomedical and biotechnology experiments. The LMM Dynamic Stage consists of an electronics module and the first two of a planned suite of experiment modules. Specimens and reagent solutions can be injected into a small, hollow microscope slide-the heart of the innovation-via a combination of small reservoirs, pumps, and valves. A life science experiment module allows investigators to load up to two different fluids for on-orbit, real-time image cytometry. Fluids can be changed to initiate a process, fix biological samples, or retrieve suspended cells. A colloid science experiment module conducts microparticle and nanoparticle tests for investigation of colloid self-assembly phenomena. This module includes a hollow glass slide and heating elements for the creation of a thermal gradient from one end of the slide to the other. The electronics module supports both experiment modules and contains a unique illuminator/condenser for bright and dark field and phase contrast illumination, power supplies for two piezoelectric pumps, and controller boards for pumps and valves. This observation platform safely contains internal fluids and will greatly accelerate the research and development (R&D) cycle of numerous experiments, products, and services aboard the ISS.

Kurk, Michael A. (Andy)↗

Observation Platform for Dynamic Biomedical and Biotechnology Experiments Using the International Space Station (ISS) Light Microscopy Module (LMM)

Techshot, Inc., has developed an observation platform for the LMM on the ISS that will enable biomedical and biotechnology experiments. The LMM Dynamic Stage consists of an electronics module and the first two of a planned suite of experiment modules. Specimens and reagent solutions can be injected into a small, hollow microscope slide-the heart of the innovation-via a combination of small reservoirs, pumps, and valves. A life science experiment module allows investigators to load up to two different fluids for on-orbit, real-time image cytometry. Fluids can be changed to initiate a process, fix biological samples, or retrieve suspended cells. A colloid science experiment module conducts microparticle and nanoparticle tests for investigation of colloid self-assembly phenomena. This module includes a hollow glass slide and heating elements for the creation of a thermal gradient from one end of the slide to the other. The electronics module supports both experiment modules and contains a unique illuminator/condenser for bright and dark field and phase contrast illumination, power supplies for two piezoelectric pumps, and controller boards for pumps and valves. This observation platform safely contains internal fluids and will greatly accelerate the research and development (R&D) cycle of numerous experiments, products, and services aboard the ISS.

Kurk, Michael A. (Andy)↗

The MISSE-9 Polymers and Composites Experiment Being Flown on the MISSE-Flight Facility

Materials on the exterior of spacecraft in low Earth orbit (LEO) are subject to extremely harsh environmental conditions, including various forms of radiation (cosmic rays, ultraviolet, x-ray, and charged particle radiation), micrometeoroids and orbital debris, temperature extremes, thermal cycling, and atomic oxygen (AO). These environmental exposures can result in erosion, embrittlement and optical property degradation of susceptible materials, threatening spacecraft performance and durability. To increase our understanding of space environmental effects such as AO erosion and radiation induced embrittlement of spacecraft materials, NASA Glenn has developed a series of experiments flown as part of the Materials International Space Station Experiment (MISSE) missions on the exterior of the International Space Station (ISS). These experiments have provided critical LEO space environment durability data such as AO erosion yield values for many materials and mechanical properties changes after long term space exposure. In continuing these studies, a new Glenn experiment has been proposed, and accepted, for flight on the new MISSE-Flight Facility (MISSE-FF). This experiment is called the Polymers and Composites Experiment and it will be flown as part of the MISSE-9 mission, the inaugural mission of MISSE-FF. Figure 1 provides an artist rendition of MISSE-FF ISS external platform. The MISSE-FF is manifested for launch on SpaceX-13.

De Groh, Kim K.↗

MIP: the First ISRU Flight Experiment

The Mars ISPP Precursor, “MIP”, was a flight experiment on the 2001 Mars Surveyor Lander that was designed to demonstrate In-situ Propellant Production-- ISPP-- for the first time on Mars. The experiment was designed to show that it was possible to produce oxygen from the carbon dioxide atmosphere, and to demonstrate the individual technology components that would go into a full-scale production plant. The aimpoint of the oxygen production was to showcase the possibility of producing oxygen for use as rocket fuel, ultimately as an enabling technology for a future human expedition to Mars. The MIP team built and qualified flight hardware for the experiment to fly on the Surveyor-2001 lander, but following the failure of the 1999 Mars Polar Lander spacecraft, the Surveyor-2001 lander mission was cancelled, and the MIP experiment was never flown. The experience in building and testing the hardware did show that the carbon dioxide electrolysis process was feasible, and led to incorporation of in-situ propellant production into the NASA reference plans for human Mars missions. Twenty years later, the technology is flying to Mars in the form of the MOXIE experiment on the Perseverance rover.

Geoffrey A Landis↗

Novel Hardware for a Lunar Plant Experiment

We propose an experiment, LPX (Lunar plant growth experiment), on the surface of the Moon that will conduct a fundamental investigation into the response of the plant Arabidopsis to lunar gravity and lunar radiation. For statistical significance, we will include more than 50 seeds. The experiment begins after lunar landing with water added to the seed platform and continues for 10 days or more. The growth of the plants, reaching ~ 1 cm high with typically 3-4 leaves in 10 days, will be monitored by camera and the carbon dioxide in the sealed chamber also will be monitored. The hardware for the LPX is based on proven technology flown on the ISS in Dec 2019 (Kitto et al. 2021, Life Sci. Space Res. in press) and the “Phytofuge” canister for Techshot MVP (Multi-use Variable-gravity Platform) centrifuge – both on ISS now. Both of these systems are TRL 9. This approach will allow identical units to be sent to the Moon and to be flown on ISS - allowing direct comparisons to partial gravity experiments done on the ISS experiment. Germination and growth of Arabidopsis requires temperature range of 20–25°C with the optimum being 22–23°C (Shymanovich and Kiss 2020, Gravit. & Space Res., 8, 1-7). This level of thermal control is a challenge on a small lunar lander and is effectively set by the latitude of the landing site. Given the mass and power limitations on a small lander, and the internal power of the LPX (~ 5W) the landing site needs to be between 73° and 77° − for which the noon time lunar surface temperatures are +15°C and -3°C (Hurley et al. 2015, Icarus 255,159-163). Within this range the temperature can be set with a small thermostatically-controlled heater These proposed experiments would be the first to grow plants on another planet and would provide important insights in terms of growth of plants on the Moon as part of bioregenerative life support.

Christopher P Mckay↗

Characterization of Novel Spacecraft Materials aboard the Materials International Space Station Experiment-Flight Facility (Preliminary Results)

This work will encompass the preflight characterization of 15 novel and heritage materials currently under observation on the Materials International Space Station Experiment-Flight Facility (MISSE-FF). MISSE-FF has been upgraded to perform active reflectance measurements of the materials. Images taken in RGB/IR colors are compared to results from an extensive ground testing campaign to obtain quantitative on-orbit material evolution data. Identical materials samples are to be flown on the ram, wake, and zenith faces of MISSE-FF, enabling deconvolution of the energetic electron, proton, atomic oxygen, and ultraviolet damage pathways. Energy deposition from the space environment leads to chemical changes in the material that in turn alter the optical properties. The same chemical damage that manifests as changes in optical reflectance and absorptance also leads to changes in myriad physical properties such as mechanical strength, electrical conductivity, and chemical reactivity. Therefore, flight materials are able to be characterized based on their unique reflectance spectra by comparing on-orbit measurements of optical reflectance with extensive terrestrial experiments, which help to correlate changes in reflectance with respect to changes in other material properties. The MISSE program has been a part of the International Space Station National Laboratory for many years and has been instrumental in understanding space weather modification of material properties. However, MISSE-FF has been limited to passive experiments with only pre/post flight material studies possible. In advance of the MISSE-16 experiment, the flight facility has received a major upgrade to provide daily spectral observations by way of a RGB/IR camera and a tunable light source. The MISSE-16 mission launched in February 2022 and carries 15 material samples for 6 months of the low Earth orbital exposure. Identical materials samples are to be flown on the ram, wake, and zenith faces of MISSE-FF, enabling deconvolution of the energetic electron, proton, atomic oxygen, and ultraviolet damage pathways. This paper discusses the MISSE-16 experiment, highlights the first use of the facility upgrades, and presents results from the extensive preflight material characterization that includes directional hemispherical reflectance, bidirectional reflectance, AFM, SEM, and electrical conductivity. Additionally, data showing the modification of these properties by ground-based exposure to space-like electron and atomic oxygen flux will be discussed. Finally, updates on deployment and initial check-out of the experiment on MISSE-FF will be presented. It is the ultimate goal of this program to provide validation for the development of ground based space weather simulation facilities and techniques.

Ryan Hoffman↗

Simulation and Development of the Radial Time Projection Chamber For the Bonus12 Experiment in CLAS12

Knowledge of the structure of nucleons (i.e. protons and neutrons) is a central topic of interest to nuclear/particle physicists. Much more is known about the structure of the proton than the neutron due to the lack of high-density free neutron targets. The Barely Off-shell Nucleon Structure experiment (BONuS12) at Jefferson Lab (JLab) is a second generation experiment upgraded/optimized to advance our knowledge of the neutron's structure using the deep-inelastic scattering of electrons off deuterium. Typically, since deuterium is a nuclear target, corrections for off-shell and nuclear binding effects must be taken into account in order to extract results on the neutron. These corrections are model-dependent and therefore have limited our success in extracting neutron information using deuterium targets. In the BONuS12 experiment, 10.6 GeV electrons are scattered off of a deuterium target. By detecting the low momentum spectator proton at backward angles, the uncertainty due to final state interactions is minimized. The goal of the experiment is to measure the ratio of the neutron to proton structure functions ($F^n_2/F^p_2$) as the Bjroken scaling variable x approaches 1. The newly designed Radial Time Projection Chamber (RTPC) for BONuS12 detects the spectator proton in coincidence with the scattered electron, which is detected in the CEBAF Large Acceptance Spectrometer (CLAS12). This work presents the simulation and development of the new BONuS12 RTPC. The design, construction, and testing of the Drift-gas Monitoring Sysytem (DMS) for the BONuS12 experiment is also described. The results of the DMS operation as well as the first preliminary data from the BONuS12 experimental run are given. Because the BONuS12 data analysis depends on CLAS12 working effectively, an effort to verify the CLAS12 operation with the extraction of the inclusive deep inelastic cross section from the first experiment in CLAS12 (Run Group A) will be presented.

Dzbenski, Nathan↗

Search for CPT and Lorentz invariance violation in the muon $g -2$ experiment at Fermilab

The Muon g-2 experiment at Fermilab (E989) aims to measure the anomalous magnetic moment of the muon, $a_{\mu}= (g-2)/2$, to a groundbreaking precision of $140$ ppb, obtaining a near four-fold increase in precision over the previous experiment, E821, at the Brookhaven National Laboratory (BNL). The value of $a_{\mu}$ from BNL currently differs from the Standard Model prediction by $\sim 3.7$ standard deviations, suggesting the potential for new physics and therefore, motivating a new experiment.Because the theory predicts this number with high precision, testing the g-factor through experiment provides a stringent test of the SM and can suggest physics beyond the Standard Model. The goal of the Fermilab Muon $g-2$ experiment is to increase the statistical precision by more than a factor of 20 and reduce systematic errors by a factor of 3. By measuring muon precession rate ($\omega_a$) in an external magnetic field, the anomalous magnetic moment will be calculated. This is an incredibly challenging experiment with a unique opportunity to provide new insight into nature. \\ The $g-2$ data also provides a great opportunity for setting the most stringent limits on some of the Standard Model Extension CPT Lorentz violating (LV) parameters in the muon sector. One of the CPT and Lorentz violating signatures that we can look for using $g-2$ data is a sidereal variation of $\omega_a(t)$. Extensive simulation studies confirm that the sensitivity regarding the sidereal varation roughly scales with $\omega_a$ uncertainty. Hence, the $g-2$ experiment at FNAL should be able to reach limits of $\sim 5\times10^{-25}$ GeV. Because the CPT and LV analyses are essentially studies of variations in $\omega_a$ as a function of time and charge, performing an $\omega_a$ analysis sets the stage for the CPT and LV measurement. This dissertation focuses on the methodology of a fully functioning framework and analyzing the Fermilab Muon $g - 2$ Run 2 data containing $\sim 11$ billion events above an energy threshold of $1.7$~GeV.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗

Reactor physics benchmark experiments at the JSI TRIGA MARK II reactor - Current status and future outlook

Full text of publication follows. With the development of new high-fidelity computational methods, improvement of nuclear data, and multiphysics modelling, there is an increased need for benchmark experiments to experimentally validate the models, methods and input data. Many of the nuclear facilities designed to perform reactor physics benchmark experiments have been shut down. Therefore, research reactors offer a great opportunity for benchmark experiments, if they are well designed and performed with great care and accuracy. In this presentation we provide an overview of the past and ongoing activities related to benchmark experiments at the Jozef Stefan Institute TRIGA Mark II research reactor. The following experiments have been performed: criticality with fresh fuel, {sup 197}Au(n,γ) and {sup 27}Al(n,α) reaction rates in irradiation channels, absolute and relative {sup 197}Au(n,γ), {sup 235}U(n,f) and {sup 238}U(n,f) reaction rates in the core, burnup, kinetic parameters, control rod worth, isothermal reactivity coefficient, self-shielding, slow and fast (pulse) transients, nuclear heating, delayed and prompt gamma ray production, temperature profiles for multi-physics. Since the existing fleet of research reactors is ageing very rapidly and new experiments are needed, new research reactors should be designed and built to meet the needs of future advanced reactors, education and training, and other technologies in the coming years. We will review planned activities at the JSI TRIGA reactors and plans for the new research reactor in Slovenia. (authors)

21 SPECIFIC NUCLEAR REACTORS AND ASSOCIATED PLANTS↗

νBDX: a Coherent Elastic Neutrino Nucleus Scattering (CEνNS) experiment at Jefferson Lab

Particle physics is an ever-changing field seeking to explain phenomena that lie at the limits of our current knowledge. Among discovered and hypothesized interactions, Coherent Elastic Neutrino-Nucleus Scattering (CE?NS) stands out as a fascinating and elusive phenomenon, offering a unique window into the nature of neutrinos and their interactions with matter. CE?NS, a process predicted by the Standard Model, represents one of the subtle ways in which neutrinos can interact with atomic nuclei. Unlike other neutrinonucleus interactions, CE?NS occurs coherently, meaning that the entire nucleus collectively responds to the neutrino-mediated weak force, resulting in small energy transfers to the nucleus as a whole. The extremely rare nature of CE?NS events presents a formidable challenge to experimenters seeking to detect and study these interactions. Recent advances in detector technologies and the implementation of large-scale experiments, such as coherent neutrino scattering experiments at research facilities around the world, have opened up new avenues for exploring this elusive phenomenon. These experiments aim not only to observe CE?NS directly but also to extract valuable information on neutrino properties, nuclear structure, and potential deviations from the Standard Model. This thesis aims to study the feasibility of an experiment to study CE?NS at The Thomas Jefferson National Accelerator Facility, Newport News, VA, USA. This would be an experiment that exploits the production of neutrinos by an electron beam dumped on a thick target (the beam dump). The large quantity of neutrinos produced and their energy profile are well suited to the purpose of studying the CE?NS. In my thesis, I will start from previous studies on CE?NS and from theoretical considerations regarding the process, then quantify the expected events for a hypothetical experiment and possible backgrounds through simulations aimed at optimizing the geometry of the future detector. I will also show some tests on selected detector components that will be part of a first prototype.

Grazzi, Stefano↗

Assessment of Measurement Uncertainties in the Jupiter High-240 Experiment

The Jupiter High-240 experiment performed in May of 2019 was previously discussed as a variant of the original Jupiter experiment incorporating plutonium metal alloy fuel plates with higher 240Pu content and lead plates, using both a reference configuration and a second configuration where eight lead plates were replaced with aluminum to simulate voiding. Measurements were recorded for experiment period, the “pressure” of the Comet ram upon closure for each near-critical measurement, and temperature. The experiment reactor period is the time it would take to increase the neutron population by a factor of e. For this experiment, the copper reflectors and upper third of the fuel sits upon a support structure with the lower fuel arrays raised up into the center of the reflectors using a ram (see Fig. 1). The recorded logbook temperature for each measurement corresponds to a resistance temperature detector (RTD) located at the top center of the upper fuel array. This paper summarizes the evaluated uncertainties for the Jupiter High 240 experiment as contributed via the recorded measurements and nuclear data and their assessed impact upon the computation of system reactivity and eigenvalue.

73 NUCLEAR PHYSICS AND RADIATION PHYSICS↗

Neutronics Analysis of Cold Critical KRUSTY Experiments using MCNP and Serpent

Kilowatt Reactor Using Stirling Technology (KRUSTY) is a prototype designed as a proof of concept for NASA’s Kilo power program, which was funded in order to create a small reactor for various space applications such as providing power for a colony on Mars or the moon and eventually as a possible option for powering rockets on deep space missions. KRUSTY was tested at the National Criticality Experiments Research Center (NCERC) located at the Nevada National Security Site (NNSS) from November 2017, through March 2018. The experimental campaign was conducted in four phases: com ponent critical experiments, cold critical experiments, warm critical runs, and high temperature demonstration. The component critical and cold critical experiments were used to determine the worth of the beryllium oxide (BeO) reflector rings and the boron carbide (B4C) control rod disks under different conditions. These conditions were altered by the addition and subtraction of other components in the assembly. The component critical phase was performed at atmospheric pressure and had four solid support rods spanning the center core; whereas the cold critical phase had the center core placed in a vacuum chamber and eight sodium-filled heat pipes spanning the center core region. This summary discusses the static neutronic analysis completed on the cold critical phase of the campaign using MCNP ® and Serpent. These two codes were used to assess any potential differences or biases in the simulation results. Understanding these potential biases is a key step toward the final goal of being able to fully analyze the transient experiments performed during phases 3 and 4 of the campaign.

21 SPECIFIC NUCLEAR REACTORS AND ASSOCIATED PLANTS↗