HTGR Knowledge Base

Conference Article: Graphite core design in UK reactors

Davies, M.W. (NNC Ltd, Knutsford, Cheshire (United Kingdom). Nuclear Engineering Div.)

Abstract

The cores in the first power producing Magnox reactors in the UK were designed with only a limited amount of information available regarding the anisotropic dimensional change behaviour of Pile Grade graphite. As more information was gained it was necessary to make modifications to the design, some minor, some major. As the cores being built became larger, and with the switch to the Advanced Gas-cooled Reactor (AGR) with its much higher power density, additional problems had to be overcome such as increased dimensional change and radiolytic oxidation by the carbon dioxide coolant. For the AGRs a more isotropic graphite was required, with a lower initial open pore volume and higher strength. Gilsocarbon graphite was developed and was selected for all the AGRs built in the UK. Methane bearing coolants are used to limit radiolytic oxidation.

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key words: Gas Cooled Reactor, Nuclear Technology
Reference:
Specialists meeting on graphite moderator lifecycle behaviour. Bath (United Kingdom). 24-27 Sep 1995.
International Atomic Energy Agency, Vienna (Austria)
IAEA-TECDOC--901, pp:47-56