I have written previously about nuclear power stations still relying on steam power to generate electricity. While we have been able to provide the direct conversion of heat to electricity for sometime it has been highly inefficient running at about 1%. The TESS system has similar issues getting their systems to profitability. Things might be changing.
A more effective way for a nuclear source to supply electricity is by employing fissionable particles themselves. Electricity is the movement of electrons to provide a current in a wire or semiconductor for example. Another view is that the positive “holes” move. Another description calls them Beta particles (positrons and / or electrons).
It is possible to use these electrons directly from radioactive decay in a process called Betavoltaics to create electricity, often using Tritium as the isotope source. Space stations and heart pacemakers have used this process in the past, but it has never really caught on due to price and possibly safety aspects. Alpha particles (helium nuclei) and gamma rays can be similarly converted directly to electricity. In fact, the latest perovskite solar panels may have improved performance over silica due to the Gammavoltaic effect.
The latest in this story is a concept called a nano diamond battery (NDB) being developed by a new startup called NDB for obvious reasons. It supposedly uses nuclear waste which it surrounds completely by a nano diamond layer that absorbs all of the energy released and converts it to electricity by “inelastic scattering”, or so the hype goes.
I am not sure about what happens next. It’s a bit like a coal fired power station in that it is always switched on, producing heat and radiation energy which will need to be used instantly or stored again, presumably in a chemical battery. NDB says they will have protypes available later this year. Watch this space, I reckon.
While it sounds like science fiction, we have been using these sorts of things in space craft for a while and their potential is enormous. NASA’s current Perseverance Mars rover is nuclear powered, using a Plutonium isotope with the power system containing a Multi-Mission Radioisotope Thermoelectric Generator, or MMRTG. This stores the electrical energy created in a couple of lithium-ion batteries. There is plenty of excess energy in this process which materialises as heat. On Mars this is not such a bad thing. It keeps the whole buggy warm and prevents it from seizing up in the cold. On Earth it would be more problematic.
Ingenuity is Perseverance’s detachable helicopter that is looking to take its first flight on Mars, probably this coming Wednesday (14 April 2021). It is lithium-ion battery powered, recharged from Perseverance’s MMRTG.
With advances in direct electric generation from radioisotopes, Small Modular Reactors (SMRs) and Nuclear Fusion we are in exciting times for electricity generation. In my view we are not quite there yet with a myriad of health, safety and economic issues yet to solve. What we need is a good, direct heat to electricity generator or serious advances in thermoelectrics. Now that would be a breakthrough.