Simple Tihange exemple

The data written in the file located at ./data/Simplest.py represents a light input of a 15x15 pins Tihange-1 (1.95%) UO2 assembly. This exemple is a reduced version of ./data/Tihange.py.

The sources used to produce this inputs are :

[1] “Qualification du système NEPTUNE” – CEA public note N-2092 by H.PANEK
[2] “In-core fuel management code package validation for PWRs” – IAEA TECDOC-815
[3] “Incertitudes et ajustement des données nucléaires au moyen des méthodes déterministes, probabilistes et de mesures effectuées sur des REP” – Ecole Polytechnique de Montreal thesis by V.SALINO
[4] “LWR nuclear fuel bundle data for use in fuel bundle handling” – Pacific Northwest Laboratory note UC-85

This chapter gives a description of this file content. To get started:

materials = pydrag.Materials(NuclearData = 'https://github.com/IRSN/PyNjoy2016/releases/download/JEFF-3.x/drglibJEFF-3.1.1')

This last line allows the user to call a specific nuclear data library. In this case, the library will be downloaded (from another Git repository, in this exemple). The Materials call will create a list of pre-defined mixtures.

Description of UO2 fuel mixture (temperature, density and composition)

materials.set_tfuel(286.1111,'C')
materials.UO2.set_density(10.96*0.95)
materials.UO2.set_enrichment('U234', 0.00019)
materials.UO2.set_enrichment('U235', 0.0195)
materials.UO2.set_enrichment('U236', 0.00012)

Those composition are taken from reference [1] for the “Region 1” composition (p.154) :

The annotation on the UO2 density precises that 10.412 g/cm^3 represents 95% of the fuel density (which equals 10.96*0.95). The fuel temperature is set to 547°F (or 286.11°C, from the same reference).

Description of water mixture (which is the moderator)

materials.water.set_temperature(286.1111,'C')
materials.water.set_density(0.716403)
materials.water.set_boron(600)

Description of Tihange grids

materials.grids.set_fraction(1.175,'Inconel','tube')
materials.grids.set_fraction(2.223,'SS304','tube')
materials.grids.set_fraction(0.5496,'Inconel','fuel')
materials.grids.set_fraction(4.166,'Inconel','gap')

Geometry made of 2 different pins (fuel F and tube T)

F = ['UO2', 0.464693,
     'void', 0.474218,
     'Zr4', 0.53594]
T = ['water', 0.65024,
     'Zr4', 0.69342]

These dimensions come from the reference [1] (p.153 and p.158):

_images/TIHANGE_UO2_pin.png — Description of a Tihange-1 fuel pin radii

_images/TIHANGE_tube_pin.png — Description of a Tihange-1 tube radii

Geometry pin layout and assembly dimensions

PinLayout = [[T, F, F, F, T, F, F, F],
                [F, F, F, F, F, F, F],
                   [F, F, F, T, F, F],
                      [T, F, F, F, F],
                         [F, F, F, F],
                            [T, F, F],
                               [F, F],
                                  [F]]
geom = pydrag.Geometry(PinLayout,PinPitch = 1.4300201,AssemblyPitch = 21.50364,ActiveHeight = 365.76)

Assembly power density parameters

powerDens = pydrag.Power(nbAssemblies = 157, corePower = 2652)

Tihange evolution calculation (with a Tihange-type grid dilution)

burnup,kinf = pydrag.Deplete(materials, geom, powerDens,TypeDil = 'Tihange')