Nuclear analysis report, nuclear subsystem
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Nuclear forensic analysis techniques work to determine the contents of radiological samples with nondestructive and destructive analysis methods. Autoradiography is a nondestructive analysis method that creates an image of the distribution of radioactivity within the sample. These images allow the location of the radiological content within a sample to be ascertained, which can be used for further analysis. Autoradiography has been used since the discovery of radiation and has been continuously developed to better suit the needs of the medical, nuclear security, nuclear safeguards, and nuclear forensic communities. Recent developments in autoradiography have led to a higher spatial resolution down to a level of tens of microns, real-time capabilities that minimize the risk of overexposure, and the ability to discriminate particles. All of these developments in autoradiography would assist the nuclear forensics community in understanding the placement of radiological content within a sample and in understanding the locations of beta-particle interactions versus those for alpha-particle interactions. This article aims to discuss the history of autoradiography as well as multiple different autoradiographic technologies while focusing on imaging plates, the BeaQuant system, and the ionizing-radiation Quantum Imaging Detector system. This article reviews three autoradiographic techniques and detectors, discusses how they relate to nuclear forensics, and addresses the drawbacks and benefits of each detector.
The MACH-1 and the THERMOS codes and their use as computational tools in nuclear analysis are examined. One dimensional survey calculations were carried out for a UF fueled core surrounded by a molten blanket; two dimensional calculations were made later with r-z geometry using the EXTERMINATOR program. Results and comparisons of the calculations are given in tabular form.
Nuclear halos are exotic quantal structures observed far from stability. They are mostly studied through reactions. The ratio of angular cross sections for breakup and scattering is predicted to be independent of the reaction process and to be very sensitive to the halo structure. Here, we test this new observable experimentally for the first time on the collision of 11 Be on C at 22.8 MeV/nucleon and using existing data on Pb at 19.1 MeV/nucleon. The theoretical predictions are verified, which offers the possibility of developing a new spectroscopic tool to study nuclear structure far from stability.
Nuclear halos are exotic quantal structures observed far from stability. They are mostly studied through reactions. The ratio of angular cross sections for breakup and scattering is predicted to be independent of the reaction process and to be very sensitive to the halo structure. We test this new observable experimentally for the first time on the collision of 11 Be on C at 22.8 MeV/nucleon and using existing data on Pb at 19.1 MeV/nucleon. The theoretical predictions are verified, which offers the possibility to develop a new spectroscopic tool to study nuclear structure far from stability.
Nuclear safety analysis as applied to a space base mission is presented. The nuclear safety analysis document summarizes the mission and the credible accidents/events which may lead to nuclear hazards to the general public. The radiological effects and associated consequences of the hazards are discussed in detail. The probability of occurrence is combined with the potential number of individuals exposed to or above guideline values to provide a measure of accident and total mission risk. The overall mission risk has been determined to be low with the potential exposure to or above 25 rem limited to less than 4 individuals per every 1000 missions performed. No radiological risk to the general public occurs during the prelaunch phase at KSC. The most significant risks occur from prolonged exposure to reactor debris following land impact generally associated with the disposal phase of the mission where fission product inventories can be high.
Exploratory calculations were performed for several gas core breeder reactor configurations. The computational method involved the use of the MACH-1 one dimensional diffusion theory code and the THERMOS integral transport theory code for thermal cross sections. Computations were performed to analyze thermal breeder concepts and nonbreeder concepts. Analysis of breeders was restricted to the (U-233)-Th breeding cycle, and computations were performed to examine a range of parameters. These parameters include U-233 to hydrogen atom ratio in the gaseous cavity, carbon to thorium atom ratio in the breeding blanket, cavity size, and blanket size.
Nondestructive medical and biologic nuclear activation analysis by computer-coupled automatic system, noting feasibility of operation
Nuclear space power systems computer simulation for preliminary system and mission analysis, considering Brayton, Rankine and thermionic systems
Nuclear thermal propulsion (NTP) is an in-space propulsion technology that uses a nuclear reactor to directly heat a propellant to provide high thrust, at higher efficiencies than achievable with conventional chemical propulsion systems. Due to the ability of NTP rockets to efficiently provide high thrust, this technology has been proposed for long duration space missions such as crewed missions to Mars and beyond. A primary hurdle for NTP technology development is the demonstration of an integrated reactor engine system to verify its functionality and performance. This primarily requires the manufacture and testing of candidate reactor and engine technologies to demonstrate the proposed design enables desired performance and exhibits acceptable response under all known operation modes. A major component in this testing is fission product accumulation, since after operation radioactive isotopes can be produced and pose radiological dose concerns. This paper explains the background behind fission product analysis and the methodology used to evaluate current reactor designs and identify the amount of fission products present and their radiological impact. Results of multiple thrust level engines at different time periods are discussed and highlight the need for additional experimental testing to confirm fractional release levels of fission products out of the system. Benchmarking of models and future paths of analysis are also discussed.
Nuclear thermal propulsion (NTP) is an in-space propulsion technology that uses a nuclear reactor to directly heat a propellant to provide high thrust, at higher efficiencies than achievable with conventional chemical propulsion systems. Due to the ability of NTP rockets to efficiently provide high thrust, this technology has been proposed for long duration space missions such as crewed missions to Mars and beyond. A primary hurdle for NTP technology development is the demonstration of an integrated reactor engine system to verify its functionality and performance. This primarily requires the manufacture and testing of candidate reactor and engine technologies to demonstrate the proposed design enables desired performance and exhibits acceptable response under all known operation modes. A major component in this testing is fission product accumulation, since after operation radioactive isotopes can be produced and pose radiological dose concerns. This paper explains the background behind fission product analysis and the methodology used to evaluate current reactor designs and identify the amount of fission products present and their radiological impact. Results of multiple thrust level engines at different time periods are discussed and highlight the need for additional experimental testing to confirm fractional release levels of fission products out of the system. Benchmarking of models and future paths of analysis are also discussed.
Aerospace nuclear safety analysis of nuclear heat source for radioisojet thrustor
Viewgraphs of probabilistic structural analysis for nuclear thermal propulsion are presented. The objective of the study was to develop a methodology to certify Space Nuclear Propulsion System (SNPS) Nozzle with assured reliability. Topics covered include: advantage of probabilistic structural analysis; space nuclear propulsion system nozzle uncertainties in the random variables; SNPS nozzle natural frequency; and sensitivity of primitive variable uncertainties SNPS nozzle natural frequency and shell stress.
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Nuclear activation analysis - technique development - applicability
Nuclear thermal propulsion has long been considered an enabling technology for human missions to Mars and beyond. One concept of operations for these missions utilizes the nuclear reactor to generate electrical power during coast phases, known as bimodal operation. This presentation focuses on the systems modeling and analysis efforts for a NERVA derived concept. The NERVA bimodal operation derives the thermal energy from the core tie tube elements. Recent analysis has shown potential temperature distributions in the tie tube elements that may limit the thermodynamic efficiency of the closed Brayton cycle used to generate electricity with the current design. The results of this analysis are discussed as well as the potential implications to a bimodal NERVA type reactor.
System-assurance-analysis (SAA) methodology developed for aerospace launch-support systems proposed for nuclear powerplants. Study shows it is feasible and practical to apply SAA methodologyto nuclear powerplants. Essentially combination of analytical techniques related to safety and reliability with information system assisting managers in making decisions affecting safety and reliability.