THE ELECTRICITY SUPPLY SYSTEM ASPECT

Problems concerning all sector performance

Fuel cycle : Fuel cycle types

Apart from MOX fuel method, which only slightly increases efficiency of uranium use, there are several much better solutions. If all transuranics from spent fuel after generating 1TWh if energy, split up, additional 18 TWh will be gained. Moreover, total fission of 25 tonnes of natural uranium will allow to obtained 208 TWh. It can be said as a theoretical consideration if not the fact that there are laboratory methods to achieve it. Then, today generation of nuclear reactors can be said as totally inefficient and because of it, uranium resources are completely wasted. Reactors that can use the fuel in more efficient way are molten uranium and thorium salt reactors. In such design the fuel is continuously purified from fission products. The prototype reactor was operating in years 60's in the USA. The design, using solution of molten salt cooling is considered by GIF as one of the generation IV reactors. There is also one more advantage of further fuel reprocessing. Time, when reduced amount of waste is considered as radioactive decreases form tens of thousands years to 500-1000 years.

Today there are three methods of spent fuel management:

  • Storage of nuclear wastes - once trough fuel cycle. In fact, this solution is a result of having no idea what to do with spent fuel. In many cases it is deposited in spent fuel water pools for undefined time.


    • Figure 26. Open, once-through fuel cycle
    Source: Own development, based on "The Future of Nuclear Power", An interdisciplinary MIT Study, Massachusetts Institute of Technology, 2003 [81]

    S. C h w a s z c z e w s k i "Cykl paliwowy: otwarty czy zamkniety. Czy to wystarczy?",
    http://www.iea.cyf.gov.pl/nowa/images/stories/iea/ej/szkola_ej/referaty/cykl_paliwowy/4_St_Chwaszczewski_cykl_paliwowy.pdf [80]


  • Spent fuel reprocessing for MOX production - MOX fuel closed cycle


    • Figure 27.Closed fuel cycle with plutonium recycle (MOX one cycle option)
    Source: Own development, based on "The Future of Nuclear Power", An interdisciplinary MIT Study, Massachusetts Institute of Technology, 2003 [81]

    S. C h w a s z c z e w s k i "Cykl paliwowy: otwarty czy zamkniety. Czy to wystarczy?",
    http://www.iea.cyf.gov.pl/nowa/images/stories/iea/ej/szkola_ej/referaty/cykl_paliwowy/4_St_Chwaszczewski_cykl_paliwowy.pdf [80]


  • Spent fuel reprocessing for uranium, plutonium and minor actinides separation for purpose its use in nuclear transmutation reaction (fuel breeding effect ) in fast neutron reactors. It is called closed fuel cycle with actinides reprocessing.


    • Figure 28.Closed fuel cycle with full actinide recycling
    Source: Own development, based on "The Future of Nuclear Power", An interdisciplinary MIT Study, Massachusetts Institute of Technology, 2003 [81]

    S. C h w a s z c z e w s k i "Cykl paliwowy: otwarty czy zamkniety. Czy to wystarczy?",
    http://www.iea.cyf.gov.pl/nowa/images/stories/iea/ej/szkola_ej/referaty/cykl_paliwowy/4_St_Chwaszczewski_cykl_paliwowy.pdf [80]

    Amount of uranium fuels and wastes in the figures and in the table are presented with assumption of nuclear power plant of 1000 MWe, generating 8 TWh of energy annually.

    Table 4.Basis types of operating reactors
    Source: Own development, based on "The Future of Nuclear Power", An interdisciplinary MIT Study, Massachusetts Institute of Technology, 2003 [81]

    S. C h w a s z c z e w s k i "Cykl paliwowy: otwarty czy zamkniety. Czy to wystarczy?",
    http://www.iea.cyf.gov.pl/nowa/images/stories/iea/ej/szkola_ej/referaty/cykl_paliwowy/4_St_Chwaszczewski_cykl_paliwowy.pdf [80]

    As it can be easily noticed after figures and table analysis, one by one fuel reprocessing methods are more efficient and they give less wastes. However using closed fuel cycle is expensive and until natural uranium prices are low, probably there will be not significant development and commercial uses of closed cycles. [80], [81], [82]

  • Copyrights 2011 © Michal Wierzbowski