Cross section calculations ECCO (European Cell COde)

IL SISTEMA DI CALCOLO
MODULARE
ERANOS
(EUROPEAN REACTOR ANALYSIS
OPTIMIZED SYSTEM)
ECCO CELL CODE
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Cross section calculations
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ECCO (European Cell COde) is the CELL code. It allows to calculate the
cross sections used in a core calculation (thanks to the Pij method).
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First, you shall create the media (homogeneous regions, physical
description, concentrations of the different isotopes, expansion
coefficients and the geometric description of the CELL which is the basis
element to construct a core)
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Then, the cross sections are calculated by using the defined media and
the nuclear libraries by means of the collision probability method.
An ECCO calculation corresponds to a succession of STEPs.
Each STEP defines an independent calculation.
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For each step you can choose:
The energy structure
The geometry (heterogeneous or homogeneous)
The processing of the flux or the balance (buckling, leakage processing)
The nuclides that are shelf-shielded
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Cross section calculations
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Many modules to condensate, homogenize or deconvolute (i.e. expand
from broad to fine group structure) allow the steps to be linked.
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Unless otherwise stated (by specifying an input library), a STEP will
use cross-section data issued from the previous step (if any).
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A STEP uses flux data issued from the previous STEP (if any) to
initialise its own flux calculations.
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A route is a recommended way to perform the ECCO calculation. The
first route is the reference route that does not worry about the time
calculation. The second route is the project route in which some
simplifying hypotheses are made (the error is still under control
regarding the reference calculation).
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The reference route treats the heterogeneous cell at the fine group
level (1968 groups).
Project (or design) route treats the elastic slowing down in a
homogeneous geometry but at the fine group level (1968 groups) and
the self-shielding in a heterogeneous geometry at the broad group
level (33 groups)
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Example of an heterogeneous step in fine groups
(part of the ECCO call sentence)
of a hexagonal fuel S/As
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Deconvoluzione
Talvolta può capitare che nell’effettuare un calcolo in struttura fine si
debba utilizzare una grandezza il cui andamento è noto in una struttura
larga.
La deconvoluzione non aggiunge alcuna informazione supplementare al
dato a pochi gruppi, serve solo a consentire l’utilizzo in calcoli a molti
gruppi.
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