Quantifying Tc-99 Contamination in a Fuel Fabrication Plant

The aging of electrical cables has been the subject of substantial research and development (R&D) projects performed by national and international laboratories, universities, and private organizations for many years. This R&D was conducted to develop guidance, equipment, and techniques to support aging management of in-service cables in industrial facilities such as nuclear power plants, research reactors, waste facilities, and fuel fabrication plants. Through these research efforts, condition monitoring technologies have been developed that can determine the severity of age-related degradation that occurs in industrial cables and insulation polymers during service. This paper summarizes the results of aging assessments that were performed for cables installed in two U.S. nuclear power plants, one a pressurized water reactor and one a boiling water reactor. These cables had been in service for over 40 years and during plant operation were exposed to harsh environmental conditions including elevated temperatures and radiation. For these assessments, a comprehensive series of measurements was performed to assess the aged condition of the cables. These cables came from different manufacturers, were manufactured in different years, and were constructed with a variety of jacket and insulation polymers including chloro-sulfonated polyethylene (CSPE), cross-linked polyethylene (XLPE)/cross-linked polyolefin (XLPO), neoprene, and ethylene propylene rubber (EPR). The goal of these assessments was to determine the current aged condition of the cable polymers and provide an estimate of how long the cable insulation materials could remain exposed to their in-service environmental conditions before reaching their end-of-life condition. Both nuclear power plants have received license renewals to extend their operation from 40 to 60 years, and the utilities need objective evidence to show that critical components such as cables will be able to function safely and reliably during the extended operating period. The results of these assessments showed that the cables exhibited different aged conditions depending on the type of polymers they were constructed with and the environment they were exposed to during service. Some of the cables and insulation polymers showed signs of significant age-related degradation and were estimated to have approximately 5 years of remaining service life. Other cables exhibited no signs of significant age-related degradation and were estimated to have 50 years or more of remaining service life. Using the results of these cable aging assessments, plant personnel were able to (1) determine the overall aged condition of cables and insulation polymers using objective test results, (2) identify aged or degraded cables before they caused operability issues, and (3) avoid unnecessary and costly replacement of cables that can continue to operate safely and reliably.

Chapter 8 - Automating Radiochemical Analysis

Worldwide, hundreds of the first generation of commercial nuclear reactors are currently entering into decommissioning. In parallel, new nuclear energy is promoted to mitigate climate change. Such energy transitions are global but take place in local landscapes, affecting the everyday lives of the elderly, adults, and children. A nuclear plant often dominates the skyline and the local identity, and its existence, disappearance, or replacement, contributes to the shaping of experiences of the past, imaginations in the present, and expectations for the future. Previous research shows a significant lack of attention to especially children’s experiences of changing energy infrastructures, and to children as active heritage producers in societal meaning-making of energy futures. This study explores children’s engagement with a decommissioning local nuclear facility through drawing workshops and conversations. Data were collected in 2023 in a school close to the Swedish nuclear power plant Barsebäck. The study highlights a particular form of heritage spatiality. A paradoxical situation of closeness and remoteness implies the industry is both a marker of one’s home and a distant façade. It is argued that children’s articulations of meaning provide a richer understanding of what constitutes local heritage, and that “decommissioning generations” is a productive lens through which a complex set of temporally diverse and heritage-relevant experiences may be discerned, enriching adult-dominated narration of changing energy landscapes.

Hybrid RO MSF desalination combines the advantages of the high desalting performance of distillation processes and lower energy requirement of membrane processes. It allows a better match between power and water requirements and enables better utilisation of the power generated from MSF into the RO. Hybrid RO MSF can lead to an optimised feedwater temperature of the RO plant since is possible to use cooling seawater from the reject stage of the MSF plant as feed to the RO plant. Higher feed temperature is advantageous for the RO plant since water flux of the membrane is about 2.5% higher per degree temperature rise at a fixed pressure. Various RO MSF combinations coupled with a nuclear power plant were studied. The optimum hybrid RO MSF scheme will be reviewed in order to illustrate the considerable gain of this option. The potential advantages of RO MSF hybrid desalination systems with nuclear plant will be discussed. The appropriate combinations depend on the local conditions and power/water requirements. The required power to water ratio and product water quality is among the important factors determining the particular RO MSF schemes to be used.

A new design paradigm for nuclear power plants is needed to complement the increasing adoption of low marginal cost variable renewable energy resources. The situation is reflected in the wholesale electricity price–duration curve with four distinct economic opportunities: (a) a hundred or so hours per year of high-value peaking power; (b) about 4000–5000 h of moderate electric prices; (c) about 2000 h per year when renewables set the marginal price at or near zero; and (d) about 1000 h of flexible ramping between the b and c regions. The current approach to the low-carbon energy transition reduces the need for baseload power and requires curtailment of conventional, nuclear, and even renewable generation, decreasing their capacity factors and increasing their fixed charges for electricity generation. Flexible low-carbon dispatchable power plants capable of daily cycling along with storage and time shifting of low-cost nondispatchable renewable power will be needed. Although nuclear power plants have demonstrated load-following capability, cycling can be limited by reactor kinetics (xenon poisoning) as well as by thermal stresses and fatigue considerations in the steam cycle. Storage of nuclear heat is hampered by the relatively low operating temperatures of existing nuclear reactors (but not advanced reactors) that lowers thermal to electric conversion efficiency, which in turn increases the required quantity of storage medium and the cost of storage. The quantity of storage medium can be reduced by integration of thermal energy storage with high-grade heat as in the liquid salt combined cycle (LSCC). The LSCC uses high-temperature gas turbine exhaust heat to increase the electricity output per unit of storage medium, uses the stored energy to add operating flexibility to a bottoming steam cycle, and substantially reduces the fuel heat rate. The low fuel heat rate improves economic competitiveness compared to alternative gas turbine-based power plants, especially when burning expensive fuels such as hydrogen. LSCC could be coupled to a nuclear power plant for time shifting both nuclear and renewable electricity and could support high utilization of a co-located hydrogen electrolysis plant. Further cost reduction could be achieved by using solid media for thermal energy storage, with the liquid salt used as a heat transfer medium.

fission produce, a resulting thermal cross section and an energy distributed resonance integral were obtained for the fission product aggregate of the three fuels as a function of P and F where F is the fractional burnup of the fuel. For F = 0 and T = 1000 deg K, the effective thermal cross sections are calculated to be 37, 43. and 54 barns per fission for 239/, respectively. At the same conditions, the excess resonance integrals below 100 ev are calculated to be 134, 172, and 266 barns per fission for U/sup 233/, U/sup 235/, and ping the individual fission products which have similar saturation characteristics, it was possible to designate four pseudoelements which when taken together yield the same total thermal cross section and resonance integral as that of the fission product aggregate over the range of P and F values considered. Multigroup cross sections were computed and are listed for each pseudoelement for use in a 32- group code. Thermal group cross sections are listed for each pseudoelement for neutron temperatures between 69 and 2704 deg F. (auth)

Microbial life can thrive in the most inhospitable places, such as nuclear facilities with high levels of ionizing radiation. Using direct meta-analyses, we have previously highlighted the presence of bacteria belonging to twenty-five different genera in the highly radioactive water of the cooling pool of an operating nuclear reactor core. In the present study, we further characterize this specific environment by isolating and identifying some of these microorganisms and assessing their radiotolerance and their ability to decontaminate uranium. This metal is one of the major radioactive contaminants of anthropogenic origin in the environment due to the nuclear and mining industries and agricultural practices. The microorganisms isolated when sampling was performed during the reactor operation consisted mainly of Actinobacteria and Firmicutes, whereas Proteobacteria were dominant when sampling was performed during the reactor shutdown. We investigated their tolerance to gamma radiation under different conditions. Most of the bacterial strains studied were able to survive 200 Gy irradiation. Some were even able to withstand 1 kGy, with four of them showing more than 10% survival at this dose. We also assessed their uranium uptake capacity. Seven strains were able to remove almost all the uranium from a 5 µM solution. Four strains displayed high efficiency in decontaminating a 50 µM uranium solution, demonstrating promising potential for use in bioremediation processes in environments contaminated by radionuclides.

Nuclear power plants that produce sustainable energy are the most striking examples of generating carbon-free energy. However, nuclear power plants demand the safe management of nuclear waste. The radiation tests of the materials, which are used in successful waste management in nuclear power plants, must be carried out. In this study, the radiation interaction parameters were examined of International simple glasses (ISG) with superior properties, used in nuclear waste management. The gamma radiation shielding properties of the (Al:Si) and (Al + Na):Si-dopped ISG glasses were investigated using Photon Shielding and Dosimetry (Phy-X / PSD) software for the selected energy range. LAC, MAC, MFP, HVL, TVL, Zeff, Neff, Ceff Zeq, EBF, EABF and FNRCS calculations were applied to assess the radiation protection parameters by Phy-X/PSD software. In addition, MSP and PR (H1, He+2) values were calculated by SRIM software. Also, each obtained parameter provided us with so important information on radiation protection, and these methods have been used frequently in the literature. Substituting an atomic fraction of (Al:Si) with (Al + Na):Si resulted in a reduction of the total atomic cross-section of the glass, which lowered the MAC. The obtained results showed that the highest MAC value belong to ISG-A00N glass. The MAC value gradually decreased as the Al, Na and Si contents increased. Likewise, the HVL, TVL and MFP values changed coherent with this. Moreover, Zeff and Neff values were seen in the ISG-A00N sample to take the maximum values to each other inversely. The most effective glass sample turned out to be ISG-A00N glass at the mean free path penetration power of MSP and PR values. Computations were made for glasses with SiO2, Al2O3, B2O3, Na2O, CaO and ZrO2 content given with ISG-C, ISG-A00, ISG-A12, ISG-A22, ISG-A00N, ISG-A11N, ISG-A18N and ISG-A23N codes. When all the results were evaluated, ISG-A00N glass which has the highest Si and Ca contents and density was found to be the glass with the best radiation shielding feature. It is also noteworthy that this glass does not contain any Al component. As the results of the investigation, it was found out that such a small doped of the Si increases the radiation shielding feature of the glass. The obtained results have revealed that the ISG-A00N > ISG-A00 > ISG-C > ISG-A12 > ISG-A11N > ISG-A22 > ISG-A18N > ISG-A23N samples, in ascending order that attenuators for low energy radiations.

The thermal and electrical resistivities of two specimens of magnesium have been measured in the temperature range 1.5 to 25\ifmmode^\circ\else\textdegree\fi{}K. One specimen was a spectrographically pure rod of 99.98+% magnesium with 0.013% iron as the major contamination. The second specimen was 99.95+% pure with 0.043% manganese as the only significant contaminant. The electrical resistivity of the purer material passed through a minimum at \ensuremath{\sim}5\ifmmode^\circ\else\textdegree\fi{}K and increased by 1.7% as the temperature was lowered to 1.5\ifmmode^\circ\else\textdegree\fi{}K. In the same specimen, the thermal resistivity at the lowest temperature exhibited a positive deviation from normal behavior (defined by $w=\ensuremath{\alpha}{T}^{2}+\frac{\ensuremath{\beta}}{T}$) of the same order of magnitude. Between 5\ifmmode^\circ\else\textdegree\fi{} and 15\ifmmode^\circ\else\textdegree\fi{}K a negative deviation was observed in the thermal resistivity.The electrical resistivity of the dilute manganese alloy specimen passed through a minimum at \ensuremath{\sim}14\ifmmode^\circ\else\textdegree\fi{}K and increased by approximately 20% as the temperature was lowered to 1.5\ifmmode^\circ\else\textdegree\fi{}K. An exactly analogous effect was found in the thermal resistivity as evidenced by (1) a constant Lorenz ratio at temperatures below 4\ifmmode^\circ\else\textdegree\fi{}K, and (2) the equality of the percentage deviations of the respective resistivities from normal behavior over the entire range of measurements.

Intergranular separation in polycrys-talline materials involves breaking metallic bonds along grain boundaries in response to stress. The surfaces created in this manner expose the grain facets on either side of the original boundary, as shown in Figure 1. This mode of fracture often occurs at much lower fracture stress and energy than cracking by ductile processes through the interior of grains. The exposure of specific materials to certain environments and stress can promote this low-energy, intergranular mode of separation, even when fracture of the same material in vacuum would occur along a ductile transgranu-lar path. Three types of environment-assisted intergranular cracking can occur in a wide variety of alloy/environment systems: intergranular stress-corrosion cracking (IGSCC), intergranular hydrogen embrittlement, and intergranular liquid-metal embrittlement.Figure 1 shows an example of IGSCC. This type of cracking is a pervasive problem in many technological applications, leading to extensive repairs, loss of service function, and safety concerns. IGSCC occurs in the weld-heat-affected zones of stainless-steel pipes in high-purity primary coolant waters within nuclear power plants, and in nickel-based alloys utilized as heat-exchanger tubing when exposed to the high-purity primary as well as secondary coolant waters in power plants. It is also seen in Al-based alloys used for fuselage skins and structural components in military and commercial aircraft when exposed to humid atmospheric conditions. Ferrous alloys used in the oil and gas industry are also susceptible. For instance, IGSCC of mild steels used in buried gas-transmission pipelines is a widespread international problem, leading to explosions when leaking natural gas ignites.

The latest estimate of the United State Energy Information Administration (US-EIA) shows that Nigeria is the largest producer of oil in Africa with largest natural gas reserves on the continent and the fifth–largest exporter of liquefied natural gas (LNG) in the World. In 2017, Nigeria's generation capacity was 12,664 megawatts (MW), with 10,522 MW representing 83% from fossil fuels, 2,110 MW representing 17% from hydropower, and 32 MW accounting for 1% coming from solar, wind, biomass, and other sources. The fossil power plants constitutes the major driver in greenhouse gas emission, therefore reduction in its operation will reduce the rate of carbon emission. To achieve carbon neutrality in line with the Paris agreement of 2015, the need for nuclear and other low carbon emission renewable electricity generation technologies is vital. This study utilizes the International Atomic Energy Agency (IAEA) Model for Energy Supply Strategy Alternatives and their General Environmental Impact (MESSAGE) code in modelling energy supply needs for Nigeria using various electricity generation technologies. By placing the upper limit on carbon emission constraints, discount rate of 11.5% and other electricity generation data obtained from EIA. Using the modelling period of forty-five (45) years with a base year of 2015 the results shows that the contribution of fossil is bound below the upper limit while that of hydro continue to increase from 2016 to the end of the modelling year. Contribution from nuclear power plant starts from 2029, and continue to increase throughout the modeling period which suppressing contribution from fossil below the upper limit of CO2, The negligible contribution from solar and wind been suppressed by nuclear and hydro power plants. The results shows that nuclear and other low carbon energy technologies are the preeminent alternative for future electricity production in achieving carbon neutrality target.

An experimental study is conducted in search of the much needed experimental method for practical and minimally destructive analysis of hydrogen (H) and deuterium (D) in a nuclear power plant. For this purpose, a picosecond (ps) Nd:YAG laser is employed and operated with 300-500 μJ output energies in a variety of ambient gases at various gas pressures. The sample chamber used is specially designed small quartz tube with an open end that can be tightly fitted to the sample surface. It is found that ambient Ar gas at reduced pressure of around 0.13 kPa gives the best spectral quality featuring fully resolved H and D emission lines with clearly detectable intensities and practically free from surface water interference. The D emission intensities measured from zircaloy plates containing various concentrations of D impurity are shown to yield a linear calibration line with extrapolated zero intercept, offering its potential application to quantitative analysis. The estimated detection limit of less than 10 ppm is well below the sensitivity limit of around 600 ppm required for the regular inspection of zircaloy tubes in a heavy water nuclear power plant. The use of the exceedingly low laser energy is shown to offer an additional advantage of minimum destructive effect marked by the resulted tiny craters of about 5 μm diameter with 25 μm depth. These results promise the potential development of the desired alternative analytical tool for regular in situ and real time inspection of the zircaloy tubes in a heavy water power plant.

Evaluation of LBB characteristics of candidate materials for main steam line piping in Korea nuclear power plants

The empirical probability of integrating CSP and its cost optimal configuration in a low carbon energy system of EUMENA

Development of simulated-gas standards