Welcome back, Puzzler fans! Our trusty sleuthing dog Gamma has a new puzzler for you. Today he's investigating a reactor using MOX fuel. Here's the puzzler:

Consider the following:

MOX fuel contains 4% plutonium and 96% uranium-238. (For simplicity we will assume that the plutonium consists of only fissile isotopes.) While plutonium is being fissioned, some of the uranium-238 is being converted into plutonium, some of which is in turn fissioned. So, destruction and build-up of plutonium are going on at the same time.

Gamma has determined that a certain reactor is fully loaded with such MOX fuel. (That is, it has a 100% MOX core.) Suppose that three-fourths of the original plutonium is converted to fission products, but 2.1% of the U-238 is also converted to plutonium.

2. How much plutonium would be left in the spent fuel if half of the new plutonium made from U-238 is fissioned also? (Round to the nearest whole percentage point.)

3. Gamma estimated that in Case 1 above, the spent fuel would have 3% fission products. Is he right? What percent of fission products exists in the spent fuel in Case 2? (For Case 2 round to the nearest whole percentage point.)