the half-life of uranium - 238 is 4.5 * 10 to the power of 9 years. The half-life of uranium-238 than that of uranium-234

Uranium-234 is an isotope of uranium. In natural uranium and in uranium ore, U-234 occurs as an indirect decay product of uranium-238, but it makes up only 0.0055% (55 parts per million) of the raw uranium because its half-life of just 245,500 years is only about 1/18,000 as long as that of U-238.