The U.S. Nuclear Regulatory Commission has scheduled the first in a planned series of workshops for next week to consider a set of recommendations from the nuclear industry to increase efficiency in licensing of dry storage systems for radioactive spent fuel at power plants.
The meeting is set for 9 a.m. to 4 p.m. Jan. 22 at agency headquarters in Rockville, Md. The topic of discussion is a November 2019 white paper from the Nuclear Energy Institute (NEI), “Defining Spent Fuel Performance Margins.”
“The goal of the meeting is to reach a common understanding of the cost-benefit associated with each recommendation along with the proposed regulatory product or outcome and to establish a prioritization and path forward for future interactions associated with each of the recommendations identified in the white paper,” the NRC said in its notice for the meeting.
The NEI white paper offers 16 recommendations, none of which are intended to require updates to existing federal regulations on storage and transportation of used fuel. They fall into three broad categories: actions that could be taken by industry, actions that could be taken at the NRC, and actions that would require collaboration by industry and the federal agency.
The current framework for federal licensing of dry-cask systems fails to apply lessons learned in over three decades of safe storage and transport of used reactor fuel, which has covered more than 3,000 vessels at over 70 nuclear facilities, according to NEI, the Washington, D.C.-based trade association for the commercial nuclear sector.
Currently, those plants store more than 80,000 metric tons of spent fuel on-site, pending eventual disposal in a federal repository. That amount increases by upward of 2,500 metric tons each year at active facilities, according to the U.S. Department of Energy.
Research by industry, the NRC, the Department of Energy, and other organizations affirmed that the hazards of dry storage and transportation of used fuel are limited, NEI said, significantly lower than the assumptions laid out in current regulations.
“An inordinate level of detail in licensing documents drives licensees and cask vendors to submit an excessive number of license amendment requests for changes to design features,” the white paper says. “As a result, industry and the U.S. Nuclear Regulatory Commission resources are diverted from more safety significant activities.”
There is potential room updating licensing practices at the industry and government levels, said Edwin Lyman, acting director of the Nuclear Safety Program at the Union of Concerned Scientists. But it is incumbent on NEI to show integrity and rigor in its case, and ensure that the safety margins leave room for uncertainty in dry-cask storage, he told RadWaste Monitor.
Lyman also cautioned against the Nuclear Regulatory Commission relinquishing oversight in favor of industry self-watch.
“You need to maintain robust safety margins where there is uncertainty,” he said by telephone. “I will be interested to see how the NRC responds to some of these proposals.”
In the past quarter-century, the NRC has authorized 74 amendments to 15 agency certificates of compliance held by vendors of dry-storage systems for various products, NEI said. Each case involves two to nine months of preparation of the amendment by the certificate holder and then a one-to-three-year evaluation of the application at the industry regulator.
“There’s only so many highly skilled licensing professionals in our world. There are people out there who are trying to license new reactor designs, there still is an operating fleet,” Rod McCullum, NEI’s senior director for fuel and decommissioning, said in a telephone interview Wednesday. “As resources get tighter, there’s a skill set that is in finite supply. Do I want that skill set being applied to tens of millions of dollars of unnecessary dry storage licenses or do I want to be applying to creating the regulation of the future?”
Among the recommendations to address the flaws NEI sees in the system:
- The NRC should establish an “Acceptance Review Grading” system to assign specific levels of intensity to the review of a license application for a storage system, based on “risk insights.”
- Three revisions to the application of “source terms” – the quantity, placement, and form of radiological material held within a storage vessel, which are used in developing safety analyses for storage casks. That would include having storage licensees and certificate holders apply “more realistic” source terms in demonstrating the viability of their container designs, rather than the more conservative bounding input assumptions that can lead to overestimated safety analysis.
- Five recommendations related to thermal limits for spent nuclear fuel in storage, in which the NRC set the maximum for peak temperature for cladding – the outer layer of fuel rods — at 400 degrees Celsius. Among these: Establishing a stepped system, with increased rigor of peak cladding temperature calculations over a broader range – for example, from 381 degrees up to 450 degrees.
The Nuclear Regulatory Commission said last month it concurs with the philosophy laid out in the NEI white paper and believes updates can be made without a formal rulemaking – a process to update its regulatoins, which can stretch on for years, sometimes over a decade.
Representatives from the NRC and NEI will be the primary participants in next week’s workshop. It also features time for presentations from industry, including dry-storage container vendors Orano, NAC International, and Holtec International.
The workshops will offer an opportunity for consideration of whether each recommendation would improve the current regulatory status and can be reasonably implemented, Andrea Kock, director of the agency’s Division of Spent Fuel Management, wrote in a Dec. 20 letter to McCullum. The sessions will also address the timeline and resource requirements for the updates.
In a follow-on Jan. 8 letter, Kock noted that the regulator had reviewed and deemed acceptable a trial run of the “Graded Approach” on an amendment to the certificate of compliance held by Orano for its NUHOMS used fuel storage system.
McCullum said he anticipates a number of meetings on the white paper, but could not say how long it might take to address all the recommendations.
“I think if we go past two years on this I might have to sit back and say is what remains really worth it? Did I accomplish enough already?” he said. “I’m not putting a definitive time frame on it.”
