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Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.

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At least 37 records · Page 2

Assessment and Accommodation of Thermal Expansion of the Internal Active Thermal Control System Coolant During Launch to On-Orbit Activation of International Space Station Elements

The International Space Station (ISS) employs an Internal Active Thermal Control System (IATCS) comprised of several single-phase water coolant loops. These coolant loops are distributed throughout the ISS pressurized elements. The primary element coolant loops (i.e. U.S. Laboratory module) contain a fluid accumulator to accomodate thermal expansion of the system. Other element coolant loops are parasitic (i.e. Airlock), have no accumulator, and require an alternative approach to insure that the system maximum design pressure (MDP) is not exceeded during the Launch to Activation (LTA) phase. During this time the element loops is a stand alone closed system. The solution approach for accomodating thermal expansion was affected by interactions of system components and their particular limitations. The mathematical solution approach was challenged by the presence of certain unknown or not readily obtainable physical and thermodynamic characteristics of some system components and processes. The purpose of this paper is to provide a brief description of a few of the solutions that evolved over time, a novel mathematical solution to eliminate some of the unknowns or derive the unknowns experimentally, and the testing and methods undertaken.

Edwards, Darryl↗

Research and Applications Modules Thermal Control System.

Research and Applications Modules (RAMs) are shuttle-compatible payload carriers providing economical experiment/payload accommodations for earth orbital space research and application objectives. The RAM Thermal Control System (TCS) incorporates a pumped fluid coolant loop to provide the flexibility for the wide range of cooling loads and mission operations. The concept employs two fluids: water inside the habitable region to absorb heat, Freon 21 outside to reject heat through radiators. The external surfaces of RAM vehicles are effectively insulated. Therefore, virtually all internally generated heat is rejected through the radiators. The selected system is described along with key analysis techniques developed during the study.

Cross, R. I.↗

International Space Station Internal Thermal Control System Lab Module Simulator Build-Up and Validation

As part of the Sustaining Engineering program for the International Space Station (ISS), a ground simulator of the Internal Thermal Control System (ITCS) in the Lab Module was designed and built at the Marshall Space Flight Center (MSFC). To support prediction and troubleshooting, this facility is operationally and functionally similar to the flight system and flight-like components were used when available. Flight software algorithms, implemented using the LabVIEW(Registered Trademark) programming language, were used for monitoring performance and controlling operation. Validation testing of the low temperature loop was completed prior to activation of the Lab module in 2001. Assembly of the moderate temperature loop was completed in 2002 and validated in 2003. The facility has been used to address flight issues with the ITCS, successfully demonstrating the ability to add silver biocide and to adjust the pH of the coolant. Upon validation of the entire facility, it will be capable not only of checking procedures, but also of evaluating payload timelining, operational modifications, physical modifications, and other aspects affecting the thermal control system.

Paul Wieland↗

Passive cooling to cold shutdown

A cooling system for a reactor module includes a reactor pressure vessel that houses primary coolant and a steam generator that lowers a temperature of the reactor pressure vessel by transferring heat from the primary coolant to a secondary coolant. The steam generator releases at least a portion of the secondary coolant as steam. Additionally, the cooling system includes a containment vessel that at least partially surrounds the reactor vessel in a containment region. The containment region is dry during normal operation of the reactor module. A controller introduces a source of water into the containment region in response to a non-emergency shut down of the reactor module. The source of water is located external to the containment vessel, and the water is introduced into the containment region after the steam generator has initially lowered the temperature of the reactor pressure vessel in response to releasing the steam.

Keller, Michael↗

Engineering aspects of a thermal control subsystem for the 25 kW power module

The paper presents the key trade study results, analysis results, and the recommended thermal control approach for the 25 kW power module defined by NASA. Power conversion inefficiencies and component heat dissipation results in a minimum heat rejection requirement of 9 kW to maintain the power module equipment at desired temperature levels. Additionally, some cooling capacity should be provided for user payloads in the sortie and free-flying modes. The baseline thermal control subsystem includes a dual-loop-pumped Freon-21 coolant with the heat rejected from deployable existing orbiter radiators. Thermal analysis included an assessment of spacecraft orientations, radiator shapes and locations, and comparison of hybrid heat pipe and all liquid panels.

Schroeder, P. E.↗

Ammonia Vent of the External Active Thermal Control System (EATCS) Radiator #3 Flow Path #2 on the International Space Station (ISS)

The External Active Thermal Control System (EATCS) provides cooling for all pressurized modules and the main Power Distribution Electronics (PDE) on the International Space Station (ISS). There are 2 EATCS loops (Loop A and Loop B) which includes 3 deployable radiators. Each deployable radiator contains 2 flow paths to provide heat rejection.Telemetry monitoring identified a coolant (liquid ammonia) leak in EATCS Loop B. Robotic External Leak Locator (RELL) scans found higher concentrations of vaporous ammonia near the EATCS Loop B Radiator #3 Flow Path #2. On May 3, 2017, the EATCS Loop B Radiator #3 Flow Path #2 was isolated and vented. As of the data to date, the ammonia leak has ceased. The purpose of this presentation is to discuss the analysis for venting the EATCS Loop B Radiator #3 Flow Path #2. Venting analysis is performed to determine the worst case time to empty the flow path and maximum thrusts imposed on the ISS. Flight controllers and engineers in the Mission Control Center (MCC) uses this data to develop operational procedures and perform the vent safely. It was predicted that the worst case time to empty the EATCS Loop B Radiator #3 Flow Path #2 was ~ 60 minutes. The predicted maximum thrusts were ~ 11 lbf (49 N) at the start of the vent and ~10 lbf (45 N) after the system reaches saturation.The vent was successfully performed and took ~ 20 minutes to empty the EATCS Loop B Radiator #3 Flow Path #2. Using telemetry from the day of the vent, analysis determined the time to empty the EATCS Loop B Radiator #3 Flow Path #2 would be ~13 minutes. The predictive analysis used worst case inputs and assumptions which bounded the actual results. Telemetry is not available to correlate actual thrust with the predicted maximum thrusts. However, by using Russian Thrusters for ISS attitude control, attitude control telemetry indicated the flight attitude was maintained.

Cowan, Darnell T.↗

Resonant Control for Fermilab's PXIE RFQ

The RFQ for Fermilab's PXIE test program is designed to accelerate a < 10 mA H⁻ CW beam to 2.1 MeV. The RFQ has a four-vane design, with four modules brazed together for a total of 4.45 m in length. The RF power required is < 130 kW at 162.5 MHz. A 3 kHz limit on the maximum allowable frequency error is imposed by the RF amplifiers. This frequency constraint must be managed entirely through differential cooling of the RFQ's vanes and outer body and associated material expansion. Simulations indicate that the body and vane coolant temperature should be controlled to within 0.1 degrees C. We present the design of the cooling network and the resonant control algorithm for this structure, as well as results from initial operation.

43 PARTICLE ACCELERATORS↗

Electrochemical carbon dioxide concentrator subsystem development

The fabrication of a one-person Electrochemical Depolarized Carbon Dioxide Concentrator subsystem incorporating advanced electrochemical, mechanical, and control and monitor instrumentation concepts is discussed. This subsystem included an advanced liquid cooled unitized core composite cell module and integrated electromechanical components. Over 1800 hours with the subsystem with removal efficiencies between 90%. and 100%; endurance tests with a Fluid Control Assembly which integrates 11 gas handling components of the subsystem; and endurance testing of a coolant control assembly which integrates a coolant pump, diverter valve and a liquid accumulator were completed.

Heppner, D. B.↗

Modeling and Simulation of the ITER First Wall/Blanket Primary Heat Transfer System

ITER inductive power operation is modeled and simulated using a thermal-hydraulics system code (RELAP5) integrated with a 3-D CFD (SC-Tetra) code. The Primary Heat Transfer System (PHTS) functions are predicted together with the main parameters operational ranges. The control algorithm strategy and derivation are summarized as well. The First Wall and Blanket modules are the primary components of PHTS, used to remove the major part of the thermal heat from the plasma. The modules represent a set of flow channels in solid metal structure that serve to absorb the radiation heat and nuclear heating from the fusion reactions and to provide shield for the vacuum vessel. The blanket modules are water cooled. The cooling is forced convective with constant blanket inlet temperature and mass flow rate. Three independent water loops supply coolant to the three blanket sectors. The main equipment of each loop consists of a pump, a steam pressurizer and a heat exchanger. A major feature of ITER is the pulsed operation. The plasma does not burn continuously, but on intervals with large periods of no power between them. This specific feature causes design challenges to accommodate the thermal expansion of the coolant during the pulse period and requires active temperature control to maintain a constant blanket inlet temperature.

70 PLASMA PHYSICS AND FUSION TECHNOLOGY↗

Design of a Loss of Coolant Blowdown Capsule for Remote Assembly with High Burnup Fuel

The Transient Water Irradiation System is an enhanced capability capsule type irradiation vehicle designed to support fuel safety research for light water reactor specimens in the Transient Reactor Test Facility and is designed to simulate loss of coolant and reactivity-initiated accidents. The capsule was designed, deployed, and commissioned with fresh fuel specimens to validate instrumentation and prepare for previously irradiated high burnup specimens. The irradiation system features an extensive in-situ instrumentation package to detect phenomena typical to light water reactor fuels. To accommodate the assembly with high burnup specimens inside the Hot Fuel Examination Facility, and to ensure instrumentation integrity is maintained throughout assembly, the design was updated to support remote handling. The updated design features a hinge mechanism which allows for remote pre-irradiated specimen loading and assembly while protecting sensitive instrumentation by relocating during loading. Fixtures and equipment have been developed to handle the experiment capsule and components in cell, and to support remote assembly. The experiment module also includes radiation shielding and contamination control to support operations after removal from the hot cell.

11 NUCLEAR FUEL CYCLE AND FUEL MATERIALS↗

Spatial homogenization of thermal feedback regions in Monte Carlo reactor calculations

An integrated thermal-hydraulic feedback module has previously been developed for the Monte Carlo transport solver, MC21. The module incorporates a flexible input format that allows the user to describe heat transfer and coolant flow paths within the geometric model at any level of spatial detail desired. The effect that the varying levels of spatial homogenization of thermal regions has on the accuracy of the Monte Carlo simulations is examined in this study. Six thermal feedback mappings are constructed from the same geometric model of the Calvert Cliffs core. The spatial homogenization of the thermal regions is varied, giving each scheme a different level of detail, and the adequacy of the spatial homogenization is determined based on the eigenvalue produced by each Monte Carlo calculation. The purpose of these numerical experiments is to determine the level of detail necessarily to accurately capture the thermal feedback effect on reactivity. Several different core models are considered: axial-flow only, axial and lateral flow, asymmetry due to control rod insertion, and fuel heating (temperature -dependent cross sections). The thermal results generated by the MC21 thermal feedback module are consistent with expectations. Based upon the numerical experiments conducted it is concluded that the amount of spatial detail necessary to accurately capture the feedback effect on reactivity is relatively small. Homogenization at the assembly level for the Calvert Cliffs PWR model results in a similar power defect to that calculated with individual pin-cells modeled as explicit thermal regions. (authors)

21 SPECIFIC NUCLEAR REACTORS AND ASSOCIATED PLANTS↗

Development of an emulation-simulation thermal control model for space station application

An improved capability for comparing various techniques for thermal management in the Space Station was developed. Current planning for the orbiting space station calls for a dual keel configuration. The thermal control system (TCS) for the space is composed of a central TCS and internal thermal control systems for the modules, as well as service facilities and attached payloads. The internal TCS may be attacted to the central TCS through a thermal bus. The central TCS is composed of a main transport system which collects waste thermal energy from each of the modules and transports it through coolant lines to the main rejection system. The waste heat loads in the modules arise from electrical and electronic equipment as well as metabolic loads in the manned modules. Several candidate technologies are being considered for acquiring the waste heat loads, for transporting the thermal energy between the acquisition and rejection systems, and for rejecting the waste heat to space. The analysis techniques described were developed for use in evaluating reliability, weights, costs, volumes, and power requirements for configurations using different candidates and different mission parameters.

Hartley, James G.↗

Thermal control system for Space Station Freedom photovoltaic power module

The electric power for Space Station Freedom (SSF) is generated by the solar arrays of the photovoltaic power modules (PVM's) and conditioned, controlled, and distributed by a power management and distribution system. The PVM's are located outboard of the alpha gimbals of SSF. A single-phase thermal control system is being developed to provide thermal control of PVM electrical equipment and energy storage batteries. This system uses ammonia as the coolant and a direct-flow deployable radiator. This paper presents the description and development status of the PVM thermal control system.

Hacha, Thomas H.↗

Thermal control system for Space Station Freedom photovoltaic power module

The electric power for Space Station Freedom (SSF) is generated by the solar arrays of the photovoltaic power modules (PVM's) and conditioned, controlled, and distributed by a power management and distribution system. The PVM's are located outboard of the alpha gimbals of SSF. A single-phase thermal control system is being developed to provide thermal control of PVM electrical equipment and energy storage batteries. This system uses ammonia as the coolant and a direct-flow deployable radiator. The description and development status of the PVM thermal control system is presented.

Hacha, Thomas H.↗

Work Domain Analysis of a Predecessor Sodium-Cooled Reactor as Baseline for AdvSMR Operational Concepts

This report presents the results of the Work Domain Analysis for the Experimental Breeder Reactor (EBR-II). This is part of the phase of the research designed to incorporate Cognitive Work Analysis in the development of a framework for the formalization of an Operational Concept (OpsCon) for Advanced Small Modular Reactors (AdvSMRs). For a new AdvSMR design, information obtained through Cognitive Work Analysis, combined with human performance criteria, can and should be used in during the operational phase of a plant to assess the crew performance aspects associated with identified AdvSMR operational concepts. The main objective of this phase was to develop an analytical and descriptive framework that will help systems and human factors engineers to understand the design and operational requirements of the emerging generation of small, advanced, multi-modular reactors. Using EBR-II as a predecessor to emerging sodium-cooled reactor designs required the application of a method suitable to the structured and systematic analysis of the plant to assist in identifying key features of the work associated with it and to clarify the operational and other constraints. The analysis included the identification and description of operating scenarios that were considered characteristic of this type of nuclear power plant. This is an invaluable aspect of Operational Concept development since it typically reveals aspects of future plant configurations that will have an impact on operations. These include, for example, the effect of core design, different coolants, reactor-to-power conversion unit ratios, modular plant layout, modular versus central control rooms, plant siting, and many more. Multi-modular plants in particular are expected to have a significant impact on overall OpsCon in general, and human performance in particular. To support unconventional modes of operation, the modern control room of a multi-module plant would typically require advanced HSIs that would provide sophisticated operational information visualization, coupled with adaptive automation schemes and operator support systems to reduce complexity. These all have to be mapped at some point to human performance requirements. The EBR-II results will be used as a baseline that will be extrapolated in the extended Cognitive Work Analysis phase to the analysis of a selected advanced sodium-cooled SMR design as a way to establish non-conventional operational concepts. The Work Domain Analysis results achieved during this phase have not only established an organizing and analytical framework for describing existing sociotechnical systems, but have also indicated that the method is particularly suited to the analysis of prospective and immature designs. The results of the EBR-II Work Domain Analysis have indicated that the methodology is scientifically sound and generalizable to any operating environment.

21 SPECIFIC NUCLEAR REACTORS AND ASSOCIATED PLANTS↗

Regenerable non-venting cooler for protective suit

A life support back pack 14 for use during extravehicular activity in space incorporates a cooling apparatus 20 comprised of five panels 22 each of which include in layered fashion a LCG coolant heat exchange coil 32, a heat distribution plate 42, and a heat dissipation module 50A or 50B having an outer radiator surface 52. Each module 50A houses a first phase change material 55A, for example hexadecane paraffin, and each module 50B houses a second phase change material 55B, for example tetradecane paraffin, which has a phase change temperature which is less than the phase change temperature of the first phase change material 55A. The cooling apparatus 20 is equipped with a coolant heat exchange circuit provided with mode selection valves 84 and 86 which are operated by a controller 88 to selectively direct the LCG coolant to be cooled through the cooling apparatus in one of three operating modes.

Roebelen, Jr., George J.↗

Fuel cell powerplant operation in Apollo spacecraft.

Primary electrical power for loads in the Apollo Command and Service Modules is furnished by a system of three fuel cell powerplants. The powerplants convert cryogenic hydrogen and oxygen into direct current. Water formed in the fuel cell reactions is supplied to the spacecraft for crew use. Waste heat is rejected through a coolant loop to a spacecraft radiator. The ability of the fuel cell to meet its voltage-power requirements and to control its own operating temperature under the environmental extremes of launch, ascent, earth orbit, translunar flight, and lunar orbit was demonstrated on successively more difficult missions leading up to the first lunar landing.

Ching, A. C.↗

Radiator heat rejection options for Shuttle payloads

The paper describes four separate advanced space radiator concepts that have been pursued in an integrated effort to develop multipayload use, low-cost heat rejection systems which can overcome the limitations of current radar systems. These four concepts are the following: (1) a wide heat load range, modularized space radiation system; (2) a heat rejection subsystem designed as a compact self-contained heat rejection module which provides a refrigeration cycle to accomodate a wide variation in payload heat loads and cooling temperature requirements; (3) a lightweight flexible fin radiator system with heat rejection capability; and (4) a radiator which does not require a circulating coolant on the radiator panel with heat pipes and thus particularly applies to very-long-duration free-flying payloads where long life reliability is an overriding design parameter. The Orbiter active thermal control system is briefly described.

Ellis, W. E.↗