237Mitigations of Human Impacts through Technology
US $1.4 billion in debt, prompting the US congress to phase out the reserve.
The resulting Helium Privatization Act of 1996 directed the US Department
of the Interior to begin emptying the reserve by 2005. The United States lost
its dominance in the world helium market in the mid-1990s. NG in Arzew,
Algeria, was found to contain extractable amounts of He; 17 million m
3
/year
was extracted at rst. Other NG wells in Algeria and Qatar were also found
to be helium rich. Algeria is now the second-leading world producer of He
(Smith et al. 2003).
Three reasons He gas is used to extract heat from pebble-bed nuclear
reactors are the following: (1) He has the highest thermal conductivity ...