NEUTRON SPECTRA IN FUSION-FISSION HYBRID REACTOR (FFHR) FOR SPENT FUEL TREATMENT

Summary

This presentation introduces a concentric model for a Fusion-Fission Hybrid Reactor (FFHR) tailored for spent nuclear fuel treatment. It details geometric and material specifications for dual fuel shells, lithium silicate breeder blankets, and tungsten reflectors, along with normalized neutron flux spectra and 14 MeV neutron shielding analyses.

Title Slide

Jorge GARCIA GALLARDO, Juana GERVASONI, Fabricio RUIZ, Nicolas GIMENEZ

Centro Atómico Bariloche, Argentina Comisión Nacional de Energía Atómica (CNEA). Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET).

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[Visuals: Green nuclear energy blocks, fusion plasma confinement concept, SPARC tokamak render, World Nuclear News graphics]

Concentric model for an FUSION-FISSION HYBRID REACTOR (FFHR)

Schematic diagram elements:

neutron generating fusion device (center, r0)
1st fuel shell (r1)
empty space (r2)
2nd fuel shell (r3)
Silicate blanket
Tungsten reflector

Parameters of the FFHR

Fuel Shell 1:

Internal radius: 40 cm
Thick: 5.4 cm
Volume: 0.1239 m³
Mass: 2366 Kg
Fuel: 8% enriched U

Fuel Shell 2:

Internal radius: 411.8 cm
Thick: 14.2 cm
Volume: 31.3 m³
Mass: 598128 Kg
Fuel: 8% enriched U

References & Notes:

A. CLAUSSE, L. SOTO, C. FRIEDLI and L. ALATAMIRANO. Feasibility study of a hybrid subcritical fission system driven by plasma-focus fusion neutrons. Annals Of Nuclear Energy, 78, (2015) pp 10-14.
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Parameters of the FFHR: Blanket

Breeder Blanket:

Internal radius: 426 cm
Thick: 50 cm
Volume: 127.7 m³

Options / Materials:

Material: Li4SiO4 | Li2SiO3
Mass [kg]: 303934 | 321813
Multiplying parameter (keff): 0.969 | 0.980

Tungsten Reflector:

Internal radius: 476 cm
Thick: 4 cm
Mass: 221659 Kg
Volume: 114.8 m³
Material: Natural W

FFHR: Normalized flux for different shells

Plots shown for:

Shell 1 (orto and meta lithium silicate)
Shell 2 (orto and meta lithium silicate)
Orto-silicate TBB vs. Metasilicate TBB
Tungsten (W) reflector

Comparison:

Comparison (PWR/FR) of 172-group spectra [FR (SPX), PWR (UOX), PWR (MOX)]
Fig. 178. Comparison of neutron spectra, for a pressurized-water reactor, and a sodium-cooled fast reactor.
Reference: J.F. PARISOT. Treatment and recycling of spent nuclear fuel, Ed. Le Moniteur, Comisariat à l’énergie nucleaire, Saclay, (2008).

Isotopes of W under 14 MeV neutron irradiation

[Decay/transmutation chain diagram of Tungsten isotopes (W-180 to W-186) and activation products under 14 MeV neutron irradiation to Ta, Re, Os, Ir, Pt, Au, Hf]

Reference: J.A. García Gallardo, M.A.N. Giménez, J.L. Gervasoni. Nuclear properties of Tungsten under 14 MeV neutron irradiation for fusion-fission hybrid reactors. Annals of Nuclear Energy 147 (2020) 107739.

Tungsten shielding capacity for 14 MeV neutrons

Tungsten shielding capacity for 14 MeV neutrons.

[2D spatial distribution heat map of neutron flux Φ(x, y=0, z)/Φ₀ through Tungsten as a function of depth z (0 to 100 cm) and lateral width x (-50 to 50 cm)].

Conclusion

Thank you!

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