LIBRA project: first tritium breeding results
Remi Delaporte-Mathurin, Nikola Goles, Colin Dunn, Emily Edwards, Samuele Meschini, Stefano Segantin, Sara Ferry, Ethan Peterson, Dennis Whyte, Edward Lamere, Kevin Woller and LIBRA collaborators
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Tritium Focus Group, 28th November 2023
The tritium issue
Cost: $30,000 per gram
Half-life: 12 years
☢
❓How ❓
Lithium is used to breed tritium
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⚛️Breeding tritium
🛡️Shield from neutrons
🔥Extract heat
Liquid Immersion Blanket
FLiBe
LIBRA: a demonstration of the LIB
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What is the smallest blanket that can demonstrate a TBR of 1?
LIBRA
Liquid Immersion Blanket tritium Robust Accountancy
Objectives
🎯T self-sufficiency with DT neutrons
🎯Experience with molten salt handling
🎯Tritium extraction from molten salts
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500L FLiBe
14 MeV neutron source
Inconel
double wall
Li + n → T + He
Neutron multiplier
The LIBRA experiment
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Tritium transport
Transport mechanisms:
- Diffusion
- Advection
Release pathways:
- Release gas/liquid interface
- Permeation through walls
The LIBRA experiment
The LIBRA experiment
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He
Tritium detection
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The actual design is a bit more complex
LIBRA was designed to achieve TBR ≈ 1
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Neutronics simulations
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Let's start smaller
- 14 MeV neutron generator 1010 n/s
- 500 L of FLiBe
→ Never done at MIT ⚠️
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The BABY programme
100 mL
ClLiF salt
Top release
Wall release
A simple 0D model is used to simulate BABY
= source - losses
inventory evolution
k mass transport coefficient
A surface area
neutron rate
Inconel 625
- 2 x 12 h irradiation
- TBR≈3×10−4
- Γn≈4×108 n/s (fitted)
- Mass transport coeffs. ki (fitted)
100 mL
CLiF salt
Top release
Wall release
THIS is what we can measure!
Salt T inventory
T fluxes
Cumulative release
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Salt crucible and two DT neutron sources
Tritium collection system
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Temperature control
The BABY experiment breeds tritium at a smaller scale
HT, T2 → HTO
#1
#2
#3
#4
HTO, TF
HT, T2
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Furnace
Tritium collection and accountancy
→ then analysed with Liquid Scintillation Counting
HTO, TF
HT, T2
15 Bq of tritium have been bred in total
Collected tritium
1 Bq = 10−15 mole of T
Collection effiency 99.8%
Model
Water is changed
Measurements agree with model
Cumulative tritium production agrees with model
Next experiments will provide information on the wall permeation
Cumulative tritium release (Bq)
- Still preliminary
- Change in dynamics to be explained:
- Unsteady neutron source?
- Change in mass transfer?
Cumulative tritium release (Bq)
2nd run showed comparable results
Next steps
- Improve repeatability
- Improve neutron detection and source characterisation
- FESTIM transport model (advection, tritium diffusion...)
- Increase volume of salt
- Switch to FLiBe
- Upgrade to LIBRA
100 mL
1 L
100 L
500 L
BABY
LIBRA
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1L of salt
Top release gas sweep
Outer-vessel for capturing permeated tritium
Thank you!
Any question?
remidm@mit.edu
LIBRA project: first tritium breeding results (TFG talk)
By Remi Delaporte-Mathurin
LIBRA project: first tritium breeding results (TFG talk)
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