Early neutron capture activation measurements by Stavisskii and Tolstikov [111] and Tolstikovet al. [112] with sealed 232 Th oxide samples are shown in Fig. 12. As later measurements were made of this cross section with metal samples, it became clear that cross sections derived from these earlier **data** were significantly larger than those obtained with metal samples. Not all measured experimental **data** sets are shown in Fig. 12. Although the authors tried to avoid water absorption in their samples, it was found later that the increase of the capture cross section could be explained qualitatively by the presence of water in those samples. Initially this difference might have been considered to be due to an USU effect. However, in this case, the physical origin of the discrepancy became known but no correction for the neutron multiple scattering due to hydrogen and subsequent capture in 232 Th, could be made. Therefore, a large uncertainty (not an USU component) should be assigned to these **data** if they are to be considered for evaluation purposes. An equivalent (and perhaps best) alternative is to discard these uncorrected **data** and not use them for **data** evaluation.