1. Toroidal Fusion Shielding Design Project
Final Presentation by:
Matt Franzi
Andrew Stach
Andrew Haefner
Ian Rittersdorf

2. Overview Fusion Power Goals Materials Design MCNP Simulations
Results and Analysis
Conclusions

3. Fusion Power
Fusing light nuclei together releases large amounts of energy
D + T = He4 + n MeV
Toroid is common geometry
Image courtesy of wikicommons

4. Toroid Fusion Reactor Plasma contained in toroid vacuum with magnets
Wall of toroid
Lithium blanket
Energy of neutrons transferred
Li Reactions
6Li + n = 4He + T MeV
7Li + n = 4He + T – 2.5 MeV
Tritium is extracted from Li and inserted in plasma

5. Two Primary Goals Tritium production Energy deposition in the blanket
Tritium breeding ratio =
tritium production flux/neutron flux
Ideally keep this above unity
Energy deposition in the blanket

6. Approach Slab model Toriod model
Initial simple model to get benchmark numbers
Toriod model
Ideal toroid model to effectively balance goals
Energy deposition
Tritium production

7. Materials Lithium Beryllium Tungsten
Tritium production reactions with neutrons
Beryllium
reflective properties
(n, 2n) reaction
Tungsten
Will not contaminate plasma

8. Slab model Simplify walls to slabs to test: material placement
Material thickness

9. Slab model results
6cm Tungsten layer first
Lithium layer

10. Final MCNP Model
Toroidal Design
ITER Size Boundaries

11. Model Cross-Section

12. Neutron Multiplication
More Neutrons = More Power = More $$
Find a way to produce more neutrons
Layers of Neutron Multipliers
Capitalize on the (n, 2n) reaction

13. Multiplication Layers
Sheets of non-lithium material
Absorbs a higher energy neutron
Produces two thermal neutrons
Is this trade off worth it?
Lithum-6 reaction with thermal neutron produces 4.8 MeV

14. Multiple Layers

15. Simulation Results