"We are not convinced of this," he said. "There will be a robust exchange of information in the coming weeks to get to the bottom of this."
Inslee and Oregon Gov. John Kitzhaber have championed building additional tanks to ensure safe storage of the waste until the plant is completed.
Wyden, whose home state neighbors the nuclear reservation, said after touring the site Tuesday that he shares their concerns about the integrity of the tanks, but that he wants more scientific information to determine it's the correct way to spend scarce money.