Regular Article

Influence of the dissolved hydrogen concentration on the radioactive contamination of the primary loops of DOEL-4 PWR using the OSCAR code

¹ CEA, DEN, 13108 Saint-Paul Lez Durance, France
² CEA, DEN, 91191 Gif-sur-Yvette, France
³ ENGIE, LABORELEC, 1630 Linkebeek, Belgium

^* e-mail: mehdi.gherrab@cea.fr

Received: 17 January 2019
Received in final form: 9 June 2019
Accepted: 22 January 2020
Published online: 25 February 2020

Abstract

Corrosion products are generated in the primary circuit during normal operation and are activated in the core. Those activated corrosion products, mainly ⁵⁸Co and ⁶⁰Co (coming respectively from the activation of ⁵⁸Ni and ⁵⁹Co), are then transported by the primary fluid and deposited on the out-of-flux surfaces (steam generators, primary coolant pipes…). To minimize this radioactive contamination, one needs to understand the behavior of corrosion products by carrying out measurements in PWRs and test loops combined with a reactor contamination assessment code named OSCAR. The aim of this article is to evaluate the influence of the change in the Dissolved Hydrogen (DH) concentration on the contamination of the primary loops of DOEL-4 PWR, a Belgian unit. After the description of the principle of the OSCAR V1.3 code, its use is illustrated with the simulation of DOEL-4. Finally, those calculations are compared to autoclave experiments called DUPLEX with thermodynamic and chemical conditions closed to those observed in PWRs. OSCAR V1.3 calculations show that an increase in the DH concentration results in a decrease in ⁵⁸Co surface activities. These results are consistent with those from the DUPLEX experiments. Finally, an increase of the DH concentration is then recommended in operating PWRs to reduce the ⁵⁸Co surface contamination.