A reactor using nuclear grade graphite as the moderator and gas or light water as the coolant. Magnox type power reactors are carbon dioxide cooled and natural uranium fuelled, with the fuel cladding of a magnesium alloy (hence the name Magnox). Advanced gas cooled reactors (AGRs) are cooled with carbon dioxide and fuelled with low enriched uranium oxide, clad in stainless steel. Reactors of the RBMK type (the acronym in Russian for 'reactor of high power, boiling') are power reactors that use graphite as the moderator and boiling light water as the coolant. The fuel is low enriched uranium oxide, clad in Zircaloy and contained in vertical pressure tubes. Magnox type power reactors, AGRs and RBMK type reactors are treated, for safeguards purposes, as item facilities. In high temperature gas cooled reactors (HTGRs), fuel can be in the form of pebbles made of oxide or carbide nuclear material particles embedded in a matrix of graphite; reactors with pebble type fuel are treated, for safeguards purposes, as bulk handling facilities.