In any new scientific venture there is bound to be dissent and alternative interpretations of the data. A number of alternative theories were proposed by Szymanski that would have disqualifed the Yucca Mountain site. These theories hypothesized geologic mechanisms that would cause very deep underlying water to rise to the level of the repository causing corrosion of the casks containing the nuclear waste, eventually releasing radionuclides to the groundwater and environment. The media and NWPO liked to portray Szymanski as a whistleblower whose theories weren't given proper attention.
Reality is something different.
The best way to dispose of the question of whether Szymanski was an unfairly dismissed whistleblower is to quote from a report from the National Research Council. Seventeen of the most highly respected scientists in the fields capable of responding to the groundwater upwelling theory were brought together in 1990 to look specifically into Szymanski's questions. The National Research Council was organized by the National Academy of Sciences in 1916 and its duty is to resolve debates of just this nature with the best scientific minds at hand, so their conclusions are the best review you can get in the world. The report claimed that such flooding had repeatedly occurred in the past and could be expected to happen again. If that were so, the water could carry still-active radioactive isotopes into the biosphere, a possibility that would lead to serious questions concerning the acceptability of the site.