The OSCAR code package : A unique tool for simulating PWR contamination
Résumé
Understanding the PWR primary circuit contamination by corrosion products, fission products
and actinides is a crucial issue for reactor operation and design. The main challenges are
decreasing the impact on personnel exposure to radiation, optimizing the plant operation,
limiting the activity of the wastes produced during the reactor lifetime and preparing
decommissioning.
In cooperation with EDF and AREVA NP, CEA has developed the OSCAR code package, a
unique tool for simulating PWR contamination. The OSCAR package results from the merging
of two codes, which simulate PWR contamination by fission products and actinides (PROFIP
code) and by activated corrosion products (PACTOLE code).
These two codes have been validated separately against an extensive set of data obtained over 40
years from in-situ gamma spectrometry measurements, sampling and analysing campaigns of
primary coolant, as well as experiments in test loops or experimental reactors, which are
representative of PWR conditions.
In this paper, a new step is presented with the OSCAR code package, combining the features of
the two codes and motivated by the fact that, wherever they originate from, the contamination
products are subject to the same severe conditions (300 °C, 150 bar, neutron flux, water velocity
up to 15 m.s-1) and follow the same transport mechanisms in the primary circuit. The main
processes involved are erosion/deposition, dissolution/precipitation, adsorption/desorption,
convection, purification, neutron activation, radioactive decrease.
The V1.1 version of the OSCAR package is qualified for fission products (Xe, Kr, I, Sr),
actinides (U, Np, Pu, Am, Cm) and corrosion products (Ni, Fe, Co, Cr).
This paper presents the different release modes (defective fuel rod release, fissile material
dissemination, material corrosion and release), then the processes which govern contamination
transfer, and finally, we give examples of the comparison of the OSCAR package results with
measurements in French PWR primary circuit obtained for representative radioisotopes : $^{133}$Xe,
$^{90}$Sr, $^{58}$Co, $^{60}$Co. In particular, we focus on the main upgrades in the OSCAR simulations compared to the
PROFIP and PACTOLE codes : adaptation of the MARGARET module to assess fission product
release out of fuel pellets in a defective rod, adsorption/desorption model development for
strontium behaviour, multi-criteria calibration of input data which are not well known for
corrosion product simulation.
Origine : Fichiers produits par l'(les) auteur(s)
Licence : CC BY - Paternité
Licence : CC BY - Paternité