Dissolution behavior of (U,Zr)O₂-based simulated fuel debris in nitric acid

Chlorination of UO2and (U,Zr)O2solid solution using MoCl5

“…The results suggest that (U 0.5 Zr 0.5 )O 2 powder was mostly converted to UCl 4 The reaction rate of the dense debris is considered to be far lower than the powder debris. Effect of higher reaction temperature up to 773 K on the reaction rate was investigated using (U 0.5 Zr 0.5 )O 2 sintered pieces and MoCl 5 . Figure 7(a) shows the appearances of products obtained by the reaction between (U 0.5 Zr 0.5 )O 2 sintered pieces and MoCl 5 at 573 K in Run 3.…”

“…The debris generated in the severe accident of Three Mile Island Unit 2 consisting of (U,Zr)O 2 was hard to be dissolved into nitric acid [4]. Also, recent results using the (U 0.5 Zr 0.5 )O 2 sim-debris indicated that its dissolution ratio was only 0.5% in 6 M HNO 3 at 353 K [5]. Therefore, a new method other than the conventional aqueous method should be developed to reprocess the debris.…”

Simultaneous analysis of gadolinium and surface imaging using a fiber-coupled acoustic wave-assisted microchip LIBS system

“…2 The debris in the FDNPS is presumed to contain uranium oxide (UO 2 ) from the fuel rods, zirconium (Zr) from the fuel rod cladding, and stainless steel (Fe, Ni, Cr) from the surrounding structural materials. 3,4 Additionally, gadolinium (Gd) is another crucial element as a trace amount of Gd oxide (Gd 2 O 3 ) was incorporated into some fuel rods in the reactor cores to control reactivity owing to its high thermal neutron capture cross-section. Therefore, detecting Gd in the fuel debris is essential for criticality control and a risk assessment of the retrieving process.…”

Thermodynamic evaluation of the solidification phase of molten core–concrete under estimated Fukushima Daiichi nuclear power plant accident conditions

“…Moreover, knowing the characteristics of the corium and MCCI products is important for decommissioning severely damaged reactors. For example, knowing the mechanical and thermal properties of the corium and MCCI products is necessary to retrieve them from a damaged reactor [4], and knowing their chemical properties is necessary for developing appropriate treatment technology [5]. The characteristics of the debris accumulated in the RPV can be estimated from those of the debris and corium produced by severe-accident experimental programs, such as the Phebus-FP and MASCA projects, at the Three Mile Island Nuclear Power Plant Unit 2 (TMI-2) [6][7][8][9].…”