# Time-dependent Neutronic Analysis for High Level Waste Transmutation in a Fusion-driven Transmuter

- First Online:

DOI: 10.1007/s10894-007-9130-1

- Cite this article as:
- Yapıcı, H., Demir, N. & Genç, G. J Fusion Energ (2008) 27: 206. doi:10.1007/s10894-007-9130-1

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## Abstract

This study presents time-dependent transmutations of high-level waste (HLW) including minor actinides (MAs) and long-lived fission products (LLFPs) in the fusion-driven transmuter (FDT) that is optimized in terms of the neutronic performance per fusion neutron in our previous study. Its blanket has two different transmutation zones (MA transmutation zone, TZ_{MA}, and LLFP transmutation zone, TZ_{FP}), located separately from each other. High burn-up pressured water reactor (PWR)-mixed oxide (MOX) spent fuel is used as HLW. The time-dependent transmutation analyses have been performed for an operation period (OP) of up to 10 years by 75% plant factor (η) under a first-wall neutron load (P) of 5 MW/m^{2}. The effective half-lives of the MA and LLFP nuclides can be shortened significantly in the considered FDT while substantial electricity is produced in situ along the OP.

### Keywords

Fusion reactors Fusion-driven transmuters Minor actinides Long-lived fission products Time-dependent transmutation### Nomenclature

*A*Area (cm

^{2})*C*_{E}Energy conversion factor (1.6021 × 10

^{−19}MWs/MeV)*C*_{m}Ratio of atomic mass to

*N*_{0}(g/atom)*E*Neutron energy (MeV)

*E*_{f}Energy per fission (200 MeV)

*k*_{eff}Neutron multiplication coefficient

*M*Blanket energy multiplication factor

*m*Mass (kg)

*n*Neutron

*N*Atomic density (atoms/cm

^{3})*N*_{a}Avogadro number (6.023 × 10

^{23}atom/mol)*N*_{x}Transmuted density of nuclide by

*x*reaction (atom/cm^{3})*P*First-wall neutron load (MW/m

^{2})*P*_{th}Thermal power production (GW

_{th})*R*_{x}*x*-Reaction rate (reactions/s)*R*_{x}*D**x*-Reaction rate density (reactions/cm^{3}/s)*t*Time (year)

*T*Total operation time (year)

*T*_{1/2}Half-life (year)

*T*_{6}Tritium breeding ratio from

^{6}Li*T*_{7}Tritium breeding ratio from

^{7}Li*V*Volume (cm

^{3})- VF
Volume fraction (%)

### Abbreviations

- BOP
Beginning of operation period

- BU
Fuel burn-up (GWd/tHM)

- B/T
Burning and/or transmutation

- C/C
Carbon/carbon

- D–T
Deuterium–tritium

- EC
Electron capture

- EOP
End of operation period

- FDT
Fusion-driven transmuter

- FW
First-wall

- HLW
High-level waste

- LLFP
Long-lived fission product

- MA
Minor actinide

- MOX
Mixed oxide

- NMZ
Neutron multiplier zone

- OP
Operation period

- PWR
Pressured water reactor

- RZ
Reflector zone

- SZ
Shielding zone

- TBR
Tritium breeding ratio

- TBZ
Tritium breeding zone

- TF
Transmutation fraction

- TR
Transmutation rate (kg/GW

_{th}year)- TRU
Transuranium

- TZ
Transmutation zone

### Greek

- α
Alpha particle

- β
Beta decay

- \( \phi \)
Neutron flux (n cm

^{−2}s^{−1})- γ
Capture

- η
Plant factor

- λ
Decay constant (1/year)

*μ*Volume fraction

*ρ*Density (g/cm

^{3})- σ
Microscopic cross-section (cm

^{2})- Δ
*t* Discrete time interval

- Φ
Number of fusion neutron per second

- Γ
Peak-to-average fission power density ratio

### Subscripts

- a
Absorption reaction

- c
Capture reaction

- dep
Depleted

- f or F
Fission

- fuel
Fuel

- FP
Long-lived fission product

- fw
First-wall

*i*Daughter nuclide

*j*Mother nuclide

*j*→*i*From

*j*to*i*- Li
_{2}O Lithium oxide

- MA
Minor actinide

- max
Maximum

*x*Transmutation reaction type (one of a, c and f reactions or F)

### Superscript

- eff
Effective