A U.S. Fish and Wildlife revised opinion regarding capping radioactive Atlas mill tailings at their current site along the Colorado River is better than the agency's original opinion, but there is still room for improvement, the Nuclear Regulatory Commission has found.

The NRC identified a number of technical, administrative and regulatory issues concerning FWS's new draft opinion, the NRC said in a formal statement released last week."Our primary interest has been, and continues to be, that all information and views be considered such that a fair, objective and implementable regulatory decision can be made," said Carl J. Paperiello, director of the NRC office of Nuclear Material Safety and Safeguards, in a letter to FWS.

"There are several instances in which it appears that the FWS did not consider the scientific analysis and basis for findings by NRC . . . or assumes NRC findings to be incorrect, without providing supporting rationale."

The NRC's formal comment is the latest step in a federal regulatory process to mitigate 10.5 millions tons of toxic mill tailings left over after decades of uranium processing at the site just outside Moab.

Atlas Corp. expressed similar concerns in its formal response to the FWS revised opinion.

The FWS's original opinion had recommended that the mill tailings be moved to a site away from the Colorado River to prevent contaminated groundwater from leaching into the river and threatening endangered fish. The opinion was sent back for revision when it was determined the NRC had no authority to order the tailings removed without congressional approval.

The subsequent FWS opinion recommended capping the mill tailings but also developing and implementing a plan to prevent contaminant leaching within two years, studying the cumulative effects of the contaminants on the fish, and draining the water left in the pile that could seep into the groundwater.

The NRC called that plan a "significant improvement" with several "reasonable and prudent" alternatives.

The NRC awaits the FWS final opinion before completing its environmental impact statement. A final decision on Atlas's proposed remediation plan will be made once the EIS is published.

The NRC has requested a meeting between the agencies to discuss issues surrounding the Atlas site.