## nuclear waste analysis problem

I am working in the nuclear waste analysis. I would really appreciate your input. We measure a content of Pu-239 in grams (radioactive element) in a long crate. There were 2 or 3 measurements on each side. Each measurement has the uncertainty.
The total mass (in grams) is measured as the sum of the masses divided by 2 since we assume that the crate is transparent that means that we measure the same mass from both sides, so we just average it.

I have a problem with the way how a total error is reported
The total error is measured as the error propagation in the quadrature, that means that the second powers of errors are added and then the square is calculated. I do not like this approach because it looks that the total error depends on the number of measurements rather than on the geometry, statistics etc. I think this approach would make sense if the measurements were completely independent, if the errors would come for instance from statistics, geometry etc. I think this is wrong since the measurements are not completely independent since we measure the same mass from both sides. The more measurements we do the higher the error.

We assume that the detector sees only a half (pr 1/3) of the container length in each measurement because of the field of view.