Fuel management study for a pebble bed modular reactor core

Movalo, Raisibe Shirley (Stellenbosch : Stellenbosch University, 2010-03)

Thesis (MSc (Physics))--Stellenbosch University, 2010.

Thesis

ENGLISH ABSTRACT: This dissertation reports on the impact of a set of selected nuclear fuel management parameters on reactor operations of the PBMR core. This is achieved by performing an assessment of the impact of nuclear fuel management parameter variations on the most important safety and economics issues for the PBMR core. These include the maximum fuel temperature at steady state and during Depressurized Loss of Forced Cooling (DLOFC) accident conditions. The reactivity worth of the Reactor Control System (RCS which determines the shutdown capability of the reactor core and the average discharge burn-up of fuel are also established. The fuel management parameters considered in this study include different enrichment levels, heavy metal loadings and fuel sphere circulation regimes. The impact and importance of these parameters on plant safety and economics is assessed. The dissertation will report the effects on the standard core physics parameters such as power peaking, multiplication factor, burn-up (safety and economics) and derive the benefits and drawbacks from the results. Based upon the findings from this study, and also experimental data, an optimum fuel management scheme is proposed for the PBMR core.

AFRIKAANSE OPSOMMING: Hierdie verhandeling beskryf die uitwerking van ‘n gekose stel kernbrandstofparameters op die bedryf van die PBMR reaktor. Die impak wat variasies in kernbrandstofparameters op belangrike veiligheids- en ekonomiese oorwegings het, is tydens hierdie studie ondersoek. Van die belangrikste oorwegings is die maksimum brandstoftemperatuur tydens normale, konstante bedryf, asook gedurende ‘n “Depressurized Loss of Forced Cooling (DLOFC)” insident waar alle verkoeling gestaak word. Ander belangrike fasette wat ondersoek is, is die reaktiwiteitwaarde van die beheerstelsel (RCS), wat die aanleg se vermoë om veilig af te sluit bepaal, asook die totale kernverbruik van die brandstof. Die kernbrandstofparameters wat in ag geneem is, sluit die brandstofverryking, swaarmetaalinhoud en die aantal brandstofsirkulasies deur die reaktorhart in. Die belangrikheid en impak van elk van hierdie parameters is ondersoek en word in die verhandeling beskryf . Daar word verslag gelewer oor die voor- en nadele, asook die uitwerking van hierdie variasies op standaard reaktorfisika-parameters soos drywingspieke in die brandstof, neutronvermenigvuldigingsfaktore en kernverbuik van die brandstof, vanaf ‘n veiligheids- en ekonomiese oogpunt. Gebaseer op die gevolgtrekkings van hierdie studie, tesame met eksperimentele data, word ‘n optimale kernbrandstofbestuurprogram voorgestel.

Please refer to this item in SUNScholar by using the following persistent URL: http://hdl.handle.net/10019.1/4234
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