Patent ID: 7094608

Claim:
A method for measuring a La content dissolved in a (U,La)O 2 nuclear fuel pellet, wherein the method comprises a step of; measuring the weight (W 1 ) of (U 1−x La x ) 3 O 8 powder obtained by oxidizing a (U 1−x La x )O 2+z pellet in an oxidizing gas atmosphere at a temperature of 300–950° C. (step 1), measuring the total weight (W 2 ) of (U 1−y La y )O 9/4 phase and U 3 O 8 phase obtained by heat treating the (U 1−x La x ) 3 O 8 powder in an oxygen-containing gas or an inert gas atmosphere at a temperature of 950–1800° C. (step 2), and measuring the La content using the following equation 1(step 3) W 1 - W 2 W 1 = M ⁢ ⁢ W O 2 × ( 5 ⁢ x 24 ⁢ y ) M ⁢ ⁢ W ( U 1 - x ⁢ La x ) ⁢ O 8 / 3 ( Equation ⁢ ⁢ 1 ) wherein MW 02 is the O 2 molecular weight, MW (U1−xLax)08/3 is the (U 1−x La x )O 8/3 molecular weight, x is the La content dissolved in (U,La)O 2 , and y is the La cation content dissolved in the (U,La)O 9/4 phase.