Pebble Bed fuel spheres ship for testing

New nuclear fuel contains 9.6% enriched uranium

Hat tip to Rod Adams at Atomic Insights

South Africa’s Pebble Bed Modular Reactor (PBMR) company has manufactured high temperature reactor fuel spheres or “pebbles” containing 9.6% enriched uranium. Most commercial nuclear fuel is enriched to 3-5%.

The “pebbles” are now entering a two-year testing phase. Successful completion of the tests will form the basis for design and construction of a fuel fabrication plant in South Africa.

PBMR said in a statement 16 of the graphite spheres had been shipped to Russia at the Institute of Nuclear Materials in Zarechny near Ekaterinburg for irradiation tests to demonstrate the fuel’s integrity under reactor conditions. The tests will begin in January 2010 and will take about two years to complete. Key issues will be the stability of the fuel and burn up rate of the U235 over time.

Fuel spheres will also be sent for irradiation testing to the Institute for Energy of the Joint Research Centre of the European Commission, at Petten in the Netherlands.

The “pebbles” will be used in a high temperature, gas cooled reactor design generating 100-165 MW of power. The primary application will be process heat. The reactors can also be used for generation of electricity.

The design is similar to one being developed by the Idaho National Laboratory for a very-high-temperature reactor (VHTR) as part of its R&D mission.

Local manufacturing capability crucial to success

The pebbles were manufactured in collaboration with the South African Nuclear Energy Corporation (Necsa). The achievement follows PBMR and Necsa’s successful manufacturing in December 2008 of enriched uranium-coated particles. There are 14 000 of them in a pebble. PBMR said this is the first time that high temperature reactor fuel has been manufactured in South Africa.

An industry source told this blog PBMR got the enriched fuel for the pebble bed fuel manufacturing process through a deal with the Russian nuclear fuel export agency. Reportedly, the 9.6% enriched uranium came from blended down HEU from Russian stockpiles of dismantled nuclear weapons.

PBMR chief executive officer Jaco Kriek (right) said the irradiation tests in Russia are the final step in the development of the fuel for the PBMR demonstration unit being built at Koeberg in South Africa.

Johan Slabber, PBMR’s chief technology officer said the test pebbles are similar to the fuel that will be used in a PBMR reactor in future. The irradiation tests will determine whether the fission product retention capability of PBMR fuel spheres is comparable with that of the German high temperature reactor fuel on which the PBMR technology is based.

Demonstration plant still on the books

The PBMR project, which is backed by the South African government, involves building both the demonstration plant at Koeberg, the site of the country’s only existing nuclear reactor unit, and a pebble fuel manufacturing plant at Pelindaba near Pretoria.

In its latest annual report, PBMR CEO Jaco Kriek estimated the demonstration plant would cost R14,5bn ($1.9 billion) to complete by 2014, and the completed fuel plant R2,3bn ($300 million), in 2013. This excludes further investments during the demonstration phase costing R6bn ($789 million).

The schedule is to start construction in 2010 and for the demonstration plant to be completed by 2014. Public Enterprises Minister Barbara Hogan said Aug 14 the government is committed to building the Pebble Bed reactor as one of its solutions to the nation’s ongoing energy crisis. At one time the government had visions of developing the PBMR for export, but for now the primary and only customer is Eskom, the key South African utility.

# # #