Nov. 15--Two St. Paul-based environmental groups have challenged a regulatory agency's decision to allow highly radioactive nuclear waste to be stored outside the Monticello, Minn., nuclear power plant.

The Minnesota Center for Environmental Advocacy and Fresh Energy asked the Minnesota Public Utilities Commission on Tuesday to reconsider its decision in late September to allow that storage to begin as early as 2008. They contend the commission disregarded state rules when it approved a certificate of need for as many as 30 above-ground storage casks.

Beth Goodpaster, an MCEA lawyer, said the commission ignored several rules, including ones obligating Xcel Energy to indicate whether the storage system is temporary or permanent and how long waste would stay there. She also said it didn't consider that a projected federal repository for nuclear waste at Yucca Mountain, Nev., as now designed, cannot accept any waste generated at Monticello after 2010.

"And Yucca Mountain is the only (repository) designed," Goodpaster said. "Those two facts contradict each other."

After the commission issued its decision in late September, the U.S. Nuclear Regulatory Commission renewed the operating license for the plant for an additional 20 years, from 2010 until 2030. Xcel has said the extra storage capacity is key to extending the life of the plant.

Commissioners likely will take up the groups' challenge within 60 days, according to energy unit manager Janet Gonzalez.

Because the commission's decision is stayed until June, the Minnesota Legislature still could interject itself into the debate. Goodpaster indicated it likely would be asked to do so if the commission rejects the reconsideration request.

"The final decision is not final until the Legislature decides whether to act, and then you have a final decision that is appealable," Goodpaster said.

Dennis Lien can be reached at dlien@pioneerpress.com or 651-228- 5588.