AbstractA chemical cleaning process for the dissolution of deposits containing iron and copper on steam generator tubes was developed. The process consists of sequences of copper and iron removal steps.The solvent for the iron removal process is a mixture of ethylene dinitrilo tetra acetic acid, citric acid, hydrazine, and a corrosion inhibitor and is applied at 90 to 95°C. The pH of the solvent is adjusted with ammonia. The composition of the solvent was optimized to balance the rate of dissolution of the deposits and the rate of corrosion of steam generator materials.Copper is removed by sparging air through a strong ammonia solution at a temperature between 25 and 65°C.The steam generator at the Nuclear Power Demonstration Nuclear Generating Station was cleaned successfully using this process. Severe fouling of the steam generator had restricted the power output of the station to ~70% of its rated value of 25 MW(electric). About 500 kg of magnetite, 200 kg of copper, and 200 kg of other metals and anions were removed, using a total of six copper removal steps and four iron removal steps. The station has returned to full power operation and is continuing to operate at full power with 3 to 4 MW(electric) of excess capacity in the steam generator.
A medium-energy gamma-ray Compton telescope called the Advanced Scintillator Compton Telescope (ASCOT) was designed to address the existing need for observations in the gamma-ray energy range of 0.4 - 20 MeV. Built on the legacy of COMPTEL instrument onboard NASA's CGRO, ASCOT uses commercially available high-performance scintillators, such as Cerium Bromide (CeBr 3 ) and p-terphenyl in conjunction with Silicon Photomultipliers (SiPM) as compact readout devices to improve the instrument response. ASCOT also makes use of the Time-of-Flight background rejection technique along with the hardware advancement, an important tool for effective imaging in this energy range. ASCOT was developed with the goal of imaging the Crab Nebula at MeV energies during a high-altitude balloon flight. The instrument was successfully launched by NASA from Palestine (TX) on 5 th July 2018. It operated stably and observed the Crab for ~5 hours from an altitude of 120,000 ft. Based on pre-flight calibrations and simulations results we expect a ~4.5 sigma detection of the Crab in the 0.2-2 MeV band. We present here the calibrated flight data along with preliminary results. The findings from ASCOT will demonstrate an improvement in the energy, timing, and position resolution using this advanced technology.
We have developed, fabricated and tested a prototype imaging neutron spectrometer designed for real-time neutron source location and identification. Real-time detection and identification is important for locating materials. These materials, specifically uranium and transuranics, emit neutrons via spontaneous or induced fission. Unlike other forms of radiation (e.g. gamma rays), penetrating neutron emission is very uncommon. The instrument detects these neutrons, constructs images of the emission pattern, and reports the neutron spectrum. The device will be useful for security and proliferation deterrence, as well as for nuclear waste characterization and monitoring. The instrument is optimized for imaging and spectroscopy in the 1-20 MeV range. The detection principle is based upon multiple elastic neutron-proton scatters in organic scintillator. Two detector panel layers are utilized. By measuring the recoil proton and scattered neutron locations and energies, the direction and energy spectrum of the incident neutrons can be determined and discrete and extended sources identified. Event reconstruction yields an image of the source and its location. The hardware is low power, low mass, and rugged. Its modular design allows the user to combine multiple units for increased sensitivity. We will report the results of laboratory testing of the instrument, including exposure to a calibrated Cf-252 source. Instrument parameters include energy and angular resolution, gamma rejection, minimum source identification distances and times, and projected effective area for a fully populated instrument.
Supermajors and larger operators are offloading mature assets to focus their capital on funding newer assets and energy transition. Investors see opportunities for free cash flow generation. Ultra-efficiency is key. Data Science is seen as a key enabler. To that end, Cantium, a brand-new data-driven independent operator was formed in 2017. This paper describes how the digital oil company was created, the data science technologies and methods that were employed, the challenges, lessons learned and critical success factors and how value was created over time.
The Canadian experimental fuel storage program consists of four components: (1) storage of used CANDU (CANadian Deuterium Uranium, registered trademark of AECL) fuel under water, with periodic examination; (2) storage of used CANDU fuel in dry air at seasonally varying temperatures, and in both dry and moisture-saturated air at 150 C, also with periodic examination; (3) underlying research on the oxidation of unused and used UO{sub 2} in dry and moist air at temperatures up to 300 C; and (4) modeling of UO{sub 2} oxidation in dry air. The primary objective of the fuel-storage experiments is to investigate the stability of used CANDU fuel during long-term storage. Burnup of the fuel in these experiments ranges from {approximately}43 to 582 MW h/kg U, while the outer-element linear power ratings range from 22 to 79 kW/m. The storage behavior of intact and intentionally defected fuel, and fuel that defected in-reactor, is being investigated in the above experiments. Since differences in UO{sub 2} oxidation behavior were observed between dry-air, moisture-saturated air and wet storage of intentionally defected used CANDU fuel, underlying research was initiated on oxidation of unused and used fuel to develop a better understanding of the different mechanisms. Modeling of UO{submore » 2} oxidation based on the results of the dry-storage experiments is also under way.« less
We have developed, fabricated and tested a prototype imaging neutron spectrometer designed for real-time neutron source location and identification. Real-time detection and identification is important for locating materials. These materials, specifically uranium and transuranics, emit neutrons via spontaneous or induced fission. Unlike other forms of radiation (e.g. gamma rays), penetrating neutron emission is very uncommon. The instrument detects these neutrons, constructs images of the emission pattern, and reports the neutron spectrum. The device will be useful for security and proliferation deterrence, as well as for nuclear waste characterization and monitoring. The instrument is optimized for imaging and spectroscopy in the 1-20 MeV range. The detection principle is based upon multiple elastic neutron-proton scatters in organic scintillator. Two detector panel layers are utilized. By measuring the recoil proton and scattered neutron locations and energies, the direction and energy spectrum of the incident neutrons can be determined and discrete and extended sources identified. Event reconstruction yields an image of the source and its location. The hardware is low power, low mass, and rugged. Its modular design allows the user to combine multiple units for increased sensitivity. We will report the results of laboratory testing of the instrument, including exposure to a calibrated Cf-252 source. Instrument parameters include energy and angular resolution, gamma rejection, minimum source identification distances and times, and projected effective area for a fully populated instrument.
This article discusses two processes that are being considered for use at the Australian Atomic Energy Commission Research Establishment at Lucas Heights, New South Wales, to decontaminate low‐level radioactive aqueous effluent in a sludge blanket clarifier. They are the calcium‐ ferric phosphate process, and the aluminum hydroxide process. Concern about the effect that detergents and complexing agents may have on the decontamination achieved by these processes provide the basis for this article.
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