Skip to main content

DOE Directs Contractor on Repository Design

I’ve spent the vast majority of my career in the nuclear industry working in waste and used fuel management. First, I interned at DOE’s Office of Civilian Radioactive Waste Management as an undergraduate, then I spent a summer in France modeling breeder reactor cores, next I worked on waste management issues at the Defense Nuclear Facilities Safety Board, for my master’s thesis I modeled gas evolution from Hanford N-Reactor fuel in sealed canisters, and I worked for seven years in Dominion’s nuclear spent fuel group.

In that time, I’ve witnessed many DOE proposals for repository design and function: a “hot” versus a “cold” repository; wet fuel transfer versus dry fuel transfer versus no fuel transfer; standard canister design versus standard canister design criteria versus “let the utilities decide what to ship it in"; and on and on. All of these proposals are technically feasible and also have pros and cons.

So, I read with great interest today DOE’s announcement that it has instructed its contractor to
devise a plan to operate the Yucca Mountain repository as a primarily “clean” or non-contaminated facility.
What this means to the layperson is that instead of transporting fuel from reactor sites to Yucca Mountain in one container, removing it (either in a pool or inert, dry environment), and then repackaging it in another container, most of the used fuel will be shipped in standardized containers that can be placed into an overpack and installed directly in the repository.

This plan makes a lot of sense.

Moving individual fuel assemblies around whenever the mood strikes is the best way to damage them. And while there are several methods to safely handle damaged fuel, they are costly and time-consuming. This proposal means that the vast majority of fuel will be handled the minimal number of times between core discharge and placement in a repository. A standardized design for the canisters would also facilitate efficient removal of the fuel for recycling if such technologies are later available.

Most importantly, I’m hopeful that focusing on this reasonable approach will, in DOE’s words, simplify the design and license application for the repository; because ultimately, after protecting the health and the safety of the public, DOE’s next greatest responsibility is to expedite the removal of used fuel from reactor sites.

Technorati tags: , ,

Comments

Solomon2 said…
for my master’s thesis I modeled gas evolution from Hanford N-Reactor fuel in sealed canisters

Hey, you're exactly the person who I hoped would catch this DOE announcement. Sure, everything can stay in the containers, but won't outgassing from fuel assemblies eventually burst the rods and release radioactives into the surroundings?
Lisa Stiles said…
No. Fuel rods and fuel containers are designed to withstand internal pressue from gases. Furthermore, when putting used fuel into a container, certain fuel characterization calculations must be done to make sure that the fuel loading does not challenge the design of the container. Parameters like gamma and neutron doses as a function of time, decay heat, and the amount of pressure that could be generated from off-gassing are determined based on the original fuel characteristics, power history, cooling time, etc.
Solomon2 said…
Specifically, I recall learning that after several hundred years the rods would burst due to the pressure generated from gaseous radioactive decay products. Is this correct?
Lisa Stiles said…
For all scenarios I can think of, no, that is not correct.

I'm sure someone could come up with some sort of chain of extremely unlikely events (fuel for which the enrichment was incorrect, plus unknowingly operating at powers beyond what a plant is licensed for, etc. etc.) after which a fuel rod could burst. But as I mentioned, fuel containers are designed to withstand high internal pressure, so there would still be no release to the surroundings.

You see, the design criteria for used fuel containers are determined by imagining the worst possible configuration. In this case, even though operators are prohibited from loading fuel that is known to have significant defects (without canning it first, but that's a different story) the container is designed to maintain its sealing integrity even if every fuel rod fails.

Popular posts from this blog

Fluor Invests in NuScale

You know, it’s kind of sad that no one is willing to invest in nuclear energy anymore. Wait, what? NuScale Power celebrated the news of its company-saving $30 million investment from Fluor Corp. Thursday morning with a press conference in Washington, D.C. Fluor is a design, engineering and construction company involved with some 20 plants in the 70s and 80s, but it has not held interest in a nuclear energy company until now. Fluor, which has deep roots in the nuclear industry, is betting big on small-scale nuclear energy with its NuScale investment. "It's become a serious contender in the last decade or so," John Hopkins, [Fluor’s group president in charge of new ventures], said. And that brings us to NuScale, which had run into some dark days – maybe not as dark as, say, Solyndra, but dire enough : Earlier this year, the Securities Exchange Commission filed an action against NuScale's lead investor, The Michael Kenwood Group. The firm "misap...

Wednesday Update

From NEI’s Japan micro-site: NRC, Industry Concur on Many Post-Fukushima Actions Industry/Regulatory/Political Issues • There is a “great deal of alignment” between the U.S. Nuclear Regulatory Commission and the industry on initial steps to take at America’s nuclear energy facilities in response to the nuclear accident in Japan, Charles Pardee, the chief operating officer of Exelon Generation Co., said at an agency briefing today. The briefing gave stakeholders an opportunity to discuss staff recommendations for near-term actions the agency may take at U.S. facilities. PowerPoint slides from the meeting are on the NRC website. • The International Atomic Energy Agency board has approved a plan that calls for inspectors to evaluate reactor safety at nuclear energy facilities every three years. Governments may opt out of having their country’s facilities inspected. Also approved were plans to maintain a rapid response team of experts ready to assist facility operators recoverin...

Nuclear Utility Moves Up in Credit Ratings, Bank is "Comfortable with Nuclear Strategy"

Some positive signs that nuclear utilities can continue to receive positive ratings even while they finance new nuclear plants for the first time in decades: Wells Fargo upgrades SCANA to Outperform from Market Perform Wells analyst says, "YTD, SCG shares have underperformed the Regulated Electrics (total return +2% vs. +9%). Shares trade at 11.3X our 10E EPS, a modest discount to the peer group median of 11.8X. We view the valuation as attractive given a comparatively constructive regulatory environment and potential for above-average long-term EPS growth prospects ... Comfortable with Nuclear Strategy. SCG plans to participate in the development of two regulated nuclear units at a cost of $6.3B, raising legitimate concerns regarding financing and construction. We have carefully considered the risks and are comfortable with SCG’s strategy based on a highly constructive political & regulatory environment, manageable financing needs stretched out over 10 years, strong partners...