A Review Of Direct Conversion of Nuclear Power to Electricity and Powerplant Efficiency

 Fluorescer compounds, a possible method to eliminate radiation damage problem.

- By Abby Gessner -

Two-Step Photon Intermediate Direct Energy Conversion (PIDEC) method uses the efficient generation of photons from the interaction of particulate radiation with fluorescer compounds as a method that eliminates the radiation damage problem. The photons are then transported to wide band-gap photovoltaic cells where electrical current is generated. PIDEC has a 40% energy conversion efficiency in a single cycle that can be applied to both large power generation systems as well as small scale nuclear batteries based on radioisotopes (Radioisotope Energy Conversion System-RECS).

The direct energy conversion system would be more efficient than the current steam cycle systems and would not use water. The system that the University of Missouri and U.S. Semiconductor Corp are developing is mechanically simple, potentially leading to more compact, more reliable and less expensive systems in the future. Mark Prelas is lead researcher.

Typically, a light-water reactor nuclear power plant offers thermal efficiency around 35%, whereas a modern coal-powered plant with super-critical boiler operates at 44%. New high temperature nuclear reactors may also reach those levels of efficiency.

The most modern gas turbines offer thermal efficiencies in the 40% range, with a recent model obtaining 46% according to reports. These values refer to simple-cycle operation, where turbine exhaust is not used further. Advantage comes from gas turbine exhaust when applied as input to a standard steam turbine in a combined-cycle power plant. This is where new-generation gas turbines can become the driving engine to obtain 60%+ overall thermal efficiency.

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  • Anonymous

    I have always believed that nuclear power offers a thermal efficiency option to coal-powered plants.  Now if we can only get the special interest groups on board, maybe we would have a viable alternative!

  • Anonymous

    It's not clear why this has popped back up a year and a half after it was originally posted, but it seems pretty clear that the author (Gessner) did not understand the source information on the PIDEC concept.  For its proposed use with a nuclear power reactor, it is clear from material that is available on the Internet that it is meant to AUGMENT a conventional steam cycle, not replace it, so the statement that it "would not use water" is at best misleading.  (The PIDEC apparatus might not use water, but the bulk of the power generation would still be via a conventional cycle--Rankine, Brayton, etc., depending on the type of reactor.)  Since most of the energy generated in a power reactor is imparted to the fission products and is extracted as heat from the fuel matrix, the direct conversion of radiation to electricity via the PIDEC system would be a secondary means of electricity generation--if it could be shown to operate effectively in the relatively hostile thermal and radiation environment of a reactor.

    It's an interesting idea, but it seems a lot more practical for use in direct conversion in radioisotope system (e.g., spacecraft power supply) than for deployment in a nuclear power reactor