Status of the nuclear measurement stations for theprocess control of spent fuel reprocessing at AREVA NC/La Hague

C. Eleon (1) , C. Passard (1) , N. Hupont (1) , N. Estre (1) , O. Gueton (1) , F. Brunner (1) , G. Grassi (2) , M. Batifol (2) , P. Doumerc (3) , T. Dupuy (4) , B. Battel (3) , J.-C. Vandamme (4)

1 CEA-DES (ex-DEN) - CEA-Direction des Energies (ex-Direction de l'Energie Nucléaire)
2 AREVA NC
3 NC - Neurosciences cognitives
4 AREVA NC–La Hague Plant, Beaumont-Hague

Nuclear measurements are used at AREVA NC/La Hague for the monitoring of spent fuel reprocessing. The process control is based on gamma-ray spectrometry, passive neutron counting and active neutron interrogation, and gamma transmission measurements. The main objectives are criticality-safety, online process monitoring, and the determination of the residual fissile mass and activities in the metallic waste remaining after fuel shearing and dissolution (empty hulls, grids, end pieces), which are put in radioactive waste drums before compaction in stainless steel containers. The whole monitoring system is composed of eight measurement stations which will be described in this paper. The main measurement stations n°1, 3 and 7 are needed for criticality control. Before fuel element shearing for dissolution, station n°1 allows determining the burn-up of the irradiated fuel by gamma-ray spectrometry with HP Ge (high purity germanium) detectors. The burn-up is correlated to the $^{137}$Cs and $^{134}$Cs gamma emission rates. The fuel maximal mass which can be loaded in one bucket of the dissolver is estimated from the lowest burn-up fraction of the fuel element. Station n°3 is dedicated to the control of the correct fuel dissolution, which is performed with a $^{137}$Cs gamma ray measurement with a HP Ge detector. Station n°7 allows estimating the residual fissile mass in the drums filled with the metallic residues, especially the hulls, from passive neutron counting (spontaneous fission and alpha-n reactions) and active interrogation (fission prompt neutrons induced by a pulsed neutron generator) with proportional $^3$He detectors. So far, large campaigns of reprocessing of the UOX fuels with a burn-up rate up to 60 GWd/t have been performed at AREVA/La Hague. This paper presents a brief overview of the current status of the nuclear measurement stations

Mots clés: Passive and active nuclear measurements Gamma-ray spectroscopy; gamma-ray transmission; Passive and active neutron measurements.

Domaines: Physique Nucléaire Expérimentale [nucl-ex]; Physique Nucléaire Théorique [nucl-th]

C. Eleon, C. Passard, N. Hupont, N. Estre, O. Gueton, et al.. Status of the nuclear measurement stations for theprocess control of spent fuel reprocessing at AREVA NC/La Hague. ANIMMA 2015 - 2015 - 4th International Conference on Advancements in Nuclear Instrumentation Measurement Methods and their Applications, Apr 2015, Lisbonne, Portugal. ⟨10.1109/ANIMMA.2015.7465631⟩. ⟨cea-02509238⟩