Thermal behaviour of chlorine in nuclear graphite at a microscopic scale

• Published in: Journal of nuclear materials 2009-12, Vol.395 (1), p.62-68
• Main Authors: Vaudey, C.E., Toulhoat, N., Moncoffre, N., Bérerd, N., Raimbault, L., Sainsot, P., Rouzaud, J.N., Perrat-Mabilon, A.
• Format: Article
• Language: English
• Subjects: Applied sciences; Controled nuclear fusion plants; Earth Sciences; Energy; Energy. Thermal use of fuels; Environmental Sciences; Exact sciences and technology; Fission nuclear power plants; Fuels; Geochemistry; Global Changes; Installations for energy generation and conversion: thermal and electrical energy; Nuclear fuels; Sciences of the Universe
• ISSN: 0022-3115; 1873-4820
• DOI: 10.1016/j.jnucmat.2009.09.018

In this paper, we present the study of thermal behaviour of 36Cl in nuclear graphite used in the St. Laurent A2 UNGG reactor (graphite moderated and CO 2 cooled reactor). 37Cl, used to simulate 36Cl displaced from its original structural site by recoil, has been implanted into nuclear graphite samples (energy = 250 keV, fluence = 5 × 10 13 at cm −2). The samples have been annealed in the 200–800 °C temperature range and analysed by SIMS. Structural modifications have been controlled by Raman microspectroscopy. This study shows that, in the considered temperature range and for a short annealing duration (4 h), chlorine is released almost athermally. At 500 °C, around 20% of the initial 37Cl content is released. At 800 °C, the release reaches a plateau and the loss of 37Cl is around 30%. Raman microspectroscopy shows that 37Cl implantation induces a structural disorder and that during annealing, the original structure is not completely recovered.