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diff --git a/doc/IGE344/SectTAVG.tex b/doc/IGE344/SectTAVG.tex new file mode 100644 index 0000000..b0d19ca --- /dev/null +++ b/doc/IGE344/SectTAVG.tex @@ -0,0 +1,130 @@ +\subsection{The \moc{TAVG:} module}\label{sect:tavg} + +\vskip 0.2cm +The \moc{TAVG:} module is used to compute the burnup integration limits for each +fuel bundle, the axial power-shape over the fuel lattice, the channel refuelling rates +and the reactor core-average exit burnup. All calculations using the \moc{TAVG:} +module are performed according to the time-average model for the equilibrium-core +conditions. The computing algorithm is based on bidirectional refuelling schemes of +channels and average exit burnups specified over the fuel lattice, which should be +recorded in the fuel map using the \moc{RESINI:} module.\\ + +Note that the complete time-average calculation is a complex and iterative procedure, +requiring of several full-core calculations (external iterations) to be performed. The main +steps of the time-average calculation using DONJON are briefly described at the end +of this section. The \moc{TAVG:} module can also be used to compute the instantaneous +fuel burnups according to the channel patterned-age-model, for the fuel management +and optimization purposes.\\ + +\noindent +The \moc{TAVG:} module specification is: + +\begin{DataStructure}{Structure \moc{TAVG:}} +\dusa{FMAP} \moc{:=} \moc{TAVG:} \dusa{FMAP} +\dusa{POWER} \moc{::} \dstr{desctavg} +\end{DataStructure} + +\noindent where + +\begin{ListeDeDescription}{mmmmmmmm} + +\item[\dusa{FMAP}] \texttt{character*12} name of a \dds{fmap} object, +that will be updated by the \moc{TAVG:} module. The \dusa{FMAP} object +must contain the average exit burnups and refuelling schemes of channels. + +\item[\dusa{POWER}] \texttt{character*12} name of a \dds{power} object +containing the channel and bundle powers, previously computed by the +\moc{FLPOW:} module. The channel and bundle powers are used by the +\moc{TAVG:} module to compute the normalized axial power-shape over +each channel. + +\item[\dstr{desctavg}] structure describing the input data to the \moc{TAVG:} module. + +\end{ListeDeDescription} + +\vskip 0.2cm +\subsubsection{Input data to the \moc{TAVG:} module}\label{sect:strtavg} + +\noindent +Note that the input order must be respected. \\ + +\begin{DataStructure}{Structure \dstr{desctavg}} +$[$ \moc{EDIT} \dusa{iprint} $]$ \\ +$[$ \moc{AX-SHAPE} $[$ \moc{RELAX} \dusa{relval} $]$ $]$ \\ +$[$ \moc{B-EXIT} $]$ \\ + ; +\end{DataStructure} + +\noindent where +\begin{ListeDeDescription}{mmmmmmmm} + +\item[\moc{EDIT}] keyword used to set \dusa{iprint}. + +\item[\dusa{iprint}] integer index used to control the printing on screen: + = 0 for no print; = 1 for minimum printing (default value); = 2 only the burnup limits +over each channel are printed; = 3 only the axial power-shape values over each channel +are printed; = 4 only the channel refuelling rates are printed; for larger values of +\dusa{iprint} everything will be printed. + +\item[\moc{AX-SHAPE}] keyword used to indicate the calculation of the new +axial power-shape and corresponding burnups limits over each reactor channel. + +\item[\moc{RELAX}] keyword used to set the relaxation parameter \dusa{relval}. + +\item[\dusa{relval}] real value of the relaxation parameter, generally used to +control the axial-shape convergence over the external time-average iterations. +The optimal value, which corresponds to the minimal total number of such iterations, +can be found by performing several runs at different \dusa{relval}. The default +value of the relaxation parameter is set to 0.5 + +\item[\moc{B-EXIT}] keyword used to indicate the calculation of the core-average +exit burnup and the channel refuelling rates. + +\end{ListeDeDescription} + +\vskip 0.2cm +\subsubsection{Time-average calculation using DONJON} + +When the average exit burnups are provided for each channel, the exact +burnup integration limits for each fuel bundle are unknown and need to be +determined. The burnups integration limits are function of the normalized +axial power-shape, which in turn depends on the flux solution over the fuel +lattice. Moreover, the flux solution depends on the fuel-map macrolib (i.e. +fuel properties), which in turn depends on the burnups integration limits for +each fuel bundle. Consequently, the time-average calculation is an iterative +procedure that consists to repeat all the steps required for the axial power-shape +computation. This repetition is to be made until the relative error between +the two (successives) axial power-shape calculations becomes as small +as required for the precision.\\ + +\noindent +The axial power-shape computing scheme is composed of several steps, +each step is performed using an appropriate DONJON or TRIVAC module: + +\begin{enumerate} +\item An initial axial power-shape is set as a flat distribution over the fuel +lattice and the first burnup integration limits are calculated approximately, +using the \moc{RESINI:} module. +\item A time-average integration is performed and a new fuel-map \dds{macrolib} +is created, using either \moc{NCR:}, \moc{CRE:} or \moc{AFM:} module. +\item An extended \dds{macrolib} over the whole reactor geometry is created, +using the \moc{MACINI:} module. +\item If the devices are inserted into the reactor core, then the previously +created \dds{macrolib} is to be updated for the devices properties using the +\moc{NEWMAC:} module. +\item The complete \dds{macrolib} is subsequently used by the \moc{TRIVAA:} +module in order to create a matrix \dds{system}. +\item The full-core numerical solution (i.e. fluxes and effective multiplication factor) +is computed, using the \moc{FLUD:} module. +\item The channel and bundle powers are next calculated, using the +\moc{FLPOW:} module. +\item Finally, the new axial power-shape and burnup limits are computed, +using the \moc{TAVG:} module. +\end{enumerate} + +\vskip 0.1cm +\noindent +Note that the steps from 2 to 8 are to be repeated until the required precision +for the axial power-shape convergence is satisfied. + +\clearpage |
