1. Collaborative Research in
Beyond PBMR
Collaborative Research in
Energy with South Africa
Bill and Geoff’s new adventure
Geoff Parks & Bill Nuttall
University of Cambridge

2. Pebble Bed Modular Reactor
Builds upon much early European work at Winfrith in the UK and Juelich in Germany
400 MWth / 165 MWe
Helium cooled
Graphite moderated
900 °C core Tout
9 MPa pressure
Brayton power cycle
On-line refueling
Source: Westinghouse Electric Company

3. Pebble Bed Modular Reactor
Vertical steel pressure vessel, 6 m in diameter, ~20 m high
Lined with 100 cm thick layer of graphite bricks (reflector and passive heat transfer medium)
Silicon carbide and pyrolitic carbon coated particles of 8% enriched UO2 encased in carbon form fuel ‘pebbles’
Fully loaded a core would
contain 380k fuel pebbles and
150k pure graphite spheres
(additional moderator)
Source:

4. Pebble Bed Modular Reactor
The reactor is continuously replenished from the top with fresh or recycled fuel pebbles, while fuel is removed from the bottom after each cycle
Pebbles are measured to determine the amount of fissile material left in them and recirculated if feasible
Each cycle lasts about three months
Each pebble passes through the reactor about 10 times

5. Source: Technology Review

6. PBMR Brayton Cycle
Source:

7. PBMR Safety
Ceramic coated fuel particles provide primary radionuclide barrier
No possible phase change in coolant
Low power density and large thermal capacity
Core heat removed passively by conduction and a natural circulation cavity cooling system
Passive heat transfer and high fuel temperature capability preclude core melt

8. PBMR Status in South Africa
In August 2008 PBMR (Pty) Ltd. announced the signing of a contract for the provision of engineering, procurement, project and construction management services for a planned demonstration reactor project at Koeberg near Cape Town
The PBMR project also includes a pebble fuel plant to be constructed at Pelindaba near Pretoria
The current schedule is to start construction in 2010 and for the demonstration plant to be completed by 2014

9. Our Proposal
A two-year project to perform a technology assessment of possible beneficial variants of the basic PBMR concept
Attributes to be considered will include:
Economics
Environmental issues
Energy security
Safety
Public acceptance
Nuclear proliferation
Nuclear skills
Industrial capacity
Industrial supply chains

10. PBMR Variants Coolants beyond helium Direct process heat applications
Steam generation (tar sands liquefaction)
Steam methane reforming (hydrogen, ammonia)
Water-splitting (bulk hydrogen, coal-to-liquids)
Desalination
Containment options
Fuel options
Alternative fuel forms
Alternative fissile materials (reactor-grade Pu or U-233 bred from Th)

11. Planned Partners University of Cape Town
Intergraph UK and South Africa
PBMR (Pty) Ltd.
The Cambridge Electricity Policy Research Group

12. Workplan 1 post-doc full time 3 UROP students
Several visits to South Africa