Not all reactors need to be shut down for refueling; for example, pebble bed reactors, AGR and CANDU reactors allow fuel to be shifted through the reactor while it is running.
32.
There have also been several experimental reactors that use graphite for moderation, such as the pebble bed reactor concepts and the molten-salt reactor experiment ( graphite core shown at right ).
33.
Until 2010 South Africa had an expansion policy based upon the Pebble Bed Modular Reactor ( PBMR ), but government financing was withdrawn because of missed deadlines and lack of customers.
34.
Two experts from Tsinghua University, one of China's leading science schools, are in South Africa helping to develop the " pebble bed " reactor, Mbeki said in a speech at Tsinghua.
35.
Kemal Turkaslan, head of the Ankara-branch of the construction engineers association, said the construction code requires that no stone bigger than a pebble be mixed with the cement for the concrete.
36.
Unresolved technical items, a substantial increase of costs and a 2008 report from Forschungszentrum J�lich about major problems in operation of the German pebble bed reactor AVR had discouraged potential investors.
37.
In 2008 Moormann published a critical paper on the safety of pebble bed reactors, which raised attention among specialists in the field, and managed to distribute it via the media, facing considerable opposition.
38.
In early 2010 the South Africa government announced it had stopped funding the development of the pebble bed modular reactor, and PBMR ( Pty ) stated it was considering 75 % cuts in staff.
39.
"' Rudolf Schulten "'( 16 August 1923 27 April 1996 ) professor at RWTH Aachen University was the main developer of the pebble bed reactor design, which was originally invented by Farrington Daniels.
40.
Kemal Turkaslan, head of the Ankara-branch of the construction engineers association said the construction code requires that no stone bigger than a pebble be used _ but grapefruit-sized stones could be seen scattered around the site.
