Economics of nuclear power plants to the extent of 3.4 billion pounds. In general, coal and nuclear plants have the same types of operating costs (operations and maintenance plus fuel costs). However, nuclear has lower fuel costs but higher operating and maintenance costs. Nuclear plants require fissile fuel. Generally, the fuel used is uranium, although other materials may be used (See MOX fuel). In 2005, prices on the world market for uranium averaged US$20/lb (US$44.09/kg). On 2007-04-19, prices reached US$113/lb (US$249.12/kg). On 2008-07-02, the price had dropped to $59/lb. Fuel costs account for about 28% of a nuclear plant's operating expenses. As of 2013, half
Interlanguage fossilization does motivation to achieve native-like competence diminish? The concept of fossilization in SLA research is so intrinsically related to interlanguage that Selinker considers it to be a fundamental phenomenon of all SLA and not just to adult learners. Fossilization has received such wide recognition that it has been entered in the "Random House Dictionary of the English Language" (1987). Selinker's concept of fossilization is similar to that of Nemser, Tarone, and Sridhar, all of whom attempted to explore the causes of fossilization in second language learners' interlanguage. Fossilization has attracted considerable interest among researchers and has engendered significant differences of