Some Notes
\”La generación estable de electricidad (energía) es la columna vertebral del desarrollo económico sostenido.\”
The currently available carbon-free energy sources include “traditional” technologies hydro and nuclear, and “non-traditional” alternative sources such as wind, solar, geothermal and other technologies.
Source: N., Gulik, V. & Tkaczyk, A. H. Cost optimization of ADS design: Comparative study of externally driven heterogeneous and homogeneous two-zone subcritical reactor systems. Nucl Eng Des 270, 133–142 (2014).
The evolution of Nuclear Power Plants (NPPs) is usually divided into four generations (GIF, 2014):
- I generation (1950–1970): early prototypes to test different technologies;
- II generation (1970–1995): medium-large commercial NPPs, mostly Light Water Reactors (LWRs), conceived to be reliable and economically competitive;
- III/III + generation (1995–2030): mostly an evolution of the II generation LWR;
- IV generation (2030+): designs called “revolutionaries” because of their discontinuity with the III/III + generation NPPs. The Generation IV International Forum (GIF) lists six GEN IV technologies (GIF, 2014):
- VHTR (Very-High-Temperature Reactor) is a thermal reactor technology cooled by helium in the gaseous phase and moderated by graphite in the solid phase;
- SFR (Sodium-cooled Fast Reactor) is a fast reactor technology cooled by sodium in the liquid phase. It is the most investigated fast reactor;
- SCWR (Supercritical-Water-cooled Reactor) is a thermal/fast reactor technology cooled by supercritical water. It is considered as an evolution of the actual boiling water reactor because of its comparable plant layout and size, same coolant and identical main application, i.e. electricity production;
- GFR (Gas-cooled Fast Reactor) is a fast reactor technology cooled by helium in the gaseous phase. This technology aims to put together a high-temperature reactor with a fast spectrum core;
- LFR (Lead-cooled Fast Reactor) is a fast reactor technology cooled by lead or lead-bismuth eutectic. It is a liquid metal reactor (similar to SFR) for electricity production and actinides management;
- MSR (Molten Salt Reactor) is a fast or thermal reactor technology cooled by molten salts in the liquid phase and moderated, in most cases, by the graphite. In this technology, the fuel can be in either liquid or solid form (Zheng et al., 2018).
Source: N., Mignacca, B. & Locatelli, G. Economics and finance of Molten Salt Reactors. Prog Nucl Energy 129, 103503 (2020).
- Power grids with limited capacity. It is a general rule that a network should not be subject to power variations greater than 10% of the total capacity of the network. Therefore, 1000 MWe plants cannot be deployed on networks of 10 GWe or less.
- Remote areas that require small, localized power centers to avoid long and expensive transmission lines.
- A geography and demography with urban areas of medium size and that need energy quite dispersed, instead of concentrated in a few “mega centers”.
- Financial capabilities that preclude raising the several billion dollars of capital investment required by larger plants, and are instead limited to the hundreds of millions of dollars typical of smaller plants.
- Need for cogeneration (desalination, district heating, industrial steam). Although, in principle, cogeneration is independent of the size of the nuclear plant, in practice economic considerations have led the larger plants to be purely electricity producers.
- Redes eléctricas con capacidad limitada. Es una regla general que una red no debe estar sujeta a variaciones de potencia superiores al 10% de la capacidad total de la red. Por lo tanto, las plantas de 1000 MWe no se pueden implementar en redes de 10 GWe o menos.
- Áreas remotas que requieren centros de energía pequeños y localizados, para evitar líneas de transmisión largas y costosas.
- Una geografía y demografía con áreas urbanas de tamaño mediano y que necesitan energía bastante dispersas, en lugar de concentradas en unos pocos “mega centros”.
- Capacidades financieras que impiden recaudar los varios miles de millones de dólares de inversión de capital que requieren las plantas más grandes y, en cambio, se limitan a cientos de millones de dólares característicos de las plantas más pequeñas.
- Necesidad de cogeneración (desalación, calefacción urbana, vapor industrial). Si bien, en principio, la cogeneración es independiente del tamaño de la planta nuclear, en la práctica las consideraciones económicas han llevado a las plantas más grandes a ser puramente productoras de electricidad.