Nevada's Nuclear Projects Agency chief said Monday the state has filed five new challenges to the Energy Department's application for a license to build a repository for the nation's highly radioactive waste at Yucca Mountain.
Bruce Breslow, executive director of the Nevada Agency for Nuclear Projects, said of key concern is the state's assertion that the DOE used "improper techniques" in a safety assessment of how fast a metal known as Alloy-22 will corrode if it is used for waste containers.
The state also repeatedly has questioned the DOE's logic behind its plan to wait 75 years to install titanium drip shields to prevent water from trickling onto waste containers entombed in a maze of tunnels inside the volcanic-rock ridge, 100 miles northwest of Las Vegas.
Breslow, speaking during a break in Monday's pre-hearing conference of a Nuclear Regulatory Commission safety and licensing panel, said the NRC staff has similar concerns.
"The NRC staff, for the first time, wrote a letter of support for the corrosion contention and drip shields," he said.
In May and July, Breslow wrote the NRC's repository safety director, Lawrence Kokajko, stating that the DOE hasn't calculated what dose the public can expect near Yucca Mountain if no drip shields are installed.
An NRC nuclear material official, Aby Mohseni, replied, saying the staff's safety review "will include careful consideration of the items you mention."
The five new challenges come after administrative judges for the licensing panel allowed all but seven of the state's original 229 challenges to be considered in the licensing review, a process that is expected to take up to four years. In all, the review will consider 299 out of 318 contentions raised by more than a dozen concerned parties.
The NRC is proceeding with the hearing process though the Obama administration and Energy Secretary Steven Chu have said Yucca Mountain is not an option for disposing 77,000 tons of used nuclear reactor fuel and highly radioactive defense waste.
Breslow said the Alloy-22 corrosion study challenge comes in addition to new safety contentions about water infiltrating the planned repository from 10,000 years to 1 million years and effects from erosion during the same time period.
Also, two challenges are related to future volcanoes affecting Yucca Mountain.
Nevada Attorney General Catherine Cortez Masto has written NRC Chairman Gregory Jaczko, expressing concern that DOE's case for safely disposing nuclear waste in Yucca Mountain depends heavily on installing more than 11,000 titanium drip shields. Doing so would cost $8 billion just for raw materials, and there is no guarantee that would occur 75 years after the first waste containers are put in the mountain.
A century from now the task of constructing drip shields and developing robotics to install them would be at least $50 billion, according to Cortez Masto.
Breslow said he has not heard back from Chu about a previous written request for the DOE to withdraw its license application with a stipulation that Yucca Mountain isn't a suitable site for burying nuclear waste.
A Yucca Project Mountain spokesman had no immediate comment on whether the Department of Energy has an appetite for withdrawing the license application.
Contact reporter Keith Rogers at firstname.lastname@example.org or 702-383-0308.