It is well known that electrical-power generation plays the key role in advances in industry, agriculture, technology, and standard of living. Also, strong power industry with diverse energy sources is very important for a country's independence. In general, electrical energy can be mainly generated from: (1) nonrenewable energy sources (75.5% of the total electricity generation) such as coal (38.3%), natural gas (23.1%), oil (3.7%), and nuclear (10.4%); and (2) renewable energy sources (24.5%) such as hydro, biomass, wind, geothermal, solar, and marine power. Today, the main sources for electrical-energy generation are: (1) thermal power (61.4%)—primarily using coal and secondarily using natural gas; (2) “large” hydro-electric plants (16.6%); and (3) nuclear power (10.4%). The balance of the energy sources (11.6%) is from using oil, biomass, wind, geothermal, and solar, and has visible impact just in a few countries. This paper presents the current status of electricity generation in the world, various sources of industrial electricity generation and role of nuclear power with a comparison of nuclear-energy systems to other energy systems. A comparison of the latest data on electricity generation with those several years old shows that world usage of coal, gas, nuclear, and oil has decreased by 1–2%, but usage of renewables has increased by 1% for hydro and 2% for other renewable sources. Unfortunately, within last years, electricity generation with nuclear power has decreased from 14% before the Fukushima Nuclear Power Plant (NPP) severe accident in March 2011 to about 10%. Therefore, it is important to evaluate current status of nuclear-power industry and to make projections on near (5–10 yr) and far away (10–25 yr and beyond) future trends.

It is well known that electrical power generation is the key factor for advances in industry, agriculture, technology, and standards of living. Also, a strong power industry with diverse energy sources is very important for a nation’s independence. In general, electrical energy can be generated from (1) burning mined and refined energy sources such as coal, natural gas, oil, and nuclear; and (2) harnessing energy sources such as hydro, biomass, wind, geothermal, solar, and wave power. Today, the main sources for electrical energy generation are (1) thermal power, primarily using coal and secondarily natural gas; (2) “large” hydraulic power from dams and rivers; and (3) nuclear power from various reactor designs. The balance of the energy sources is from using oil, biomass, wind, geothermal, and solar, which have a visible impact just in some countries. This paper presents the current status and role of the nuclear-power industry in the world with a comparison of nuclear-energy systems to other energy systems.

It is well known that electrical power generation is the key factor for advances in industry, agriculture, and standard of living. In general, electrical energy can be generated by (1) nonrenewable energy sources such as coal, natural gas, oil, and nuclear; and (2) renewable energy sources such as hydro, wind, solar, biomass, geothermal, and marine. However, the main sources for electrical energy generation are (1) thermal—primarily coal and secondary natural gas, (2) “large” hydro, and (3) nuclear. Other energy sources might have a level of impact in some countries. Modern advanced thermal power plants have reached very high thermal efficiencies (55–62%). In spite of that, they are still the largest emitters of carbon dioxide into the atmosphere. Therefore, reliable non–fossil fuel energy generation, such as nuclear power, is becoming more and more attractive. However, current nuclear power plants (NPPs) are way behind in thermal efficiency (30–42%) compared to the efficiency of advanced thermal power plants. Therefore, it is important to consider various ways to enhance the thermal efficiency of NPPs. This paper presents a comparison of thermodynamic cycles and layouts of modern NPPs and discusses ways to improve their thermal efficiencies.

The appropriate description of heat transfer to coolants at the supercritical state is limited by the current understanding. Thus, this poses one of the main challenges in the development of supercritical-fluids applications for Generation-IV reactors. Since the thermodynamic critical point of water is much higher than that of carbon dioxide ($CO2$), it is more affordable to run heat-transfer experiments in supercritical $CO2$. The data for supercritical $CO2$ can be later scaled and used for supercritical water-based reactor designs. The objective of this paper is, therefore, to discuss the basis for comparison of relatively recent experimental data on supercritical $CO2$ obtained at the facilities of the Korea Atomic Energy Research Institute (KAERI) and Chalk River Laboratories (CRL) of the Atomic Energy of Canada Limited (AECL). Based on the available instrumental error, a thorough analysis of experimental errors in wall- and bulk-fluid temperatures and heat transfer coefficient was conducted. A revised heat-transfer correlation for the CRL data is presented. A dimensional criterion for the onset of the deteriorated heat transfer in the form of a linear relation between heat flux and mass flux is proposed. A preliminary heat-transfer correlation for the joint CRL and KAERI datasets is presented.

Due to emerging climate change concerns coupled with increased global energy demand, eventually the world needs to move to low-carbon-emission electricity-generating sources—nonrenewables, such as nuclear power, and renewables, as hydro, wind, geothermal, solar, and tidal. The only source is nuclear power that is reliable, concentrated, and can be of large installed capacity and operate with high capacity factors. This paper updates and presents the current status of nuclear-power deployment and small modular reactors (SMRs) development in the world. Unfortunately, within last 9 years, electricity generation with nuclear power has decreased from ∼14% before the Fukushima Nuclear Power Plant (NPP) severe accident in March of 2011 to about ∼10%. Therefore, it is important to follow up with and understand the latest trends in nuclear power including SMRs development.

Supercritical water-cooled nuclear reactors (SCWRs) are a Generation IV reactor concept. SCWRs will use a light-water coolant at operating parameters set above the critical point of water (22.1 MPa and $374°C$). One reason for moving from current Nuclear Power Plant (NPP) designs to SCW NPP designs is to increase the thermal efficiency. The thermal efficiency of existing NPPs is between 30% and 35% compared with 45% and 50% of supercritical water (SCW) NPPs. Another benefit of SCWRs is the use of a simplified flow circuit, in which steam generators, steam dryers, steam separators, etc. can be eliminated. Canada is in the process of conceptualizing a pressure tube (PT) type SCWR. This concept refers to a $1200-MWel$ PT-type reactor. Coolant operating parameters are as follows: a pressure of 25 MPa, a channel inlet temperature of $350°C$, and an outlet temperature of $625°C$. The sheath material and nuclear fuel must be able to withstand these extreme conditions. In general, the primary choice for the sheath is a zirconium alloy and the fuel is an enriched uranium dioxide $(UO2)$. The sheath-temperature design limit is $850°C$, and the industry accepted limit for the fuel centerline temperature is $1850°C$. Previous studies have shown that the maximum fuel centerline temperature of a $UO2$ pellet might exceed this industry accepted limit at SCWR conditions. Therefore, alternative fuels with higher thermal conductivities need to be investigated for SCWR use. Uranium carbide (UC), uranium nitride (UN), and uranium dicarbide $(UC2)$ are excellent fuel choices as they all have higher thermal conductivities compared with conventional nuclear fuels such as $UO2$, mixed oxides (MOX), and thoria $(ThO2)$. Inconel-600 has been selected as the sheath material due its high corrosion resistance and high yield strength in aggressive supercritical water (SCW) at high-temperatures. This paper presents the thermalhydraulics calculations of a generic PT-type SCWR fuel channel with a 43-element Inconel-600 bundle with UC and $UC2$ fuels. The bulk-fluid, sheath and fuel centerline temperature profiles, together with a heat transfer coefficient profile, were calculated for a generic PT-type SCWR fuel-bundle string. Fuel bundles with UC and $UC2$ fuels with various axial heat flux profiles (AHFPs) are acceptable since they do not exceed the sheath-temperature design limit of $850°C$, and the industry accepted limit for the fuel centerline temperature of $1850°C$. The most desirable case in terms of the lowest fuel centerline temperature is the UC fuel with the upstream-skewed cosine AHFP. In this case, the fuel centerline temperature does not exceed even the sheath-temperature design limit of $850°C$.