Rethinking the Relevance of Nuclear Fuel Age

By Tristan Krueger '20
Hometown: Bend, OR
Major: Computer Science and Creative Writing
Intern, Western Interstate Energy Board

Three weeks before our final webinar about spent nuclear fuel, my partner, Cheng, and I were already putting finishing touches on the presentation. The summer had passed quickly, but we were well ahead of schedule. The week before, we had given a draft of the webinar to Ken Niles, the chair of the High Level Radioactive Waste Committee (HLRW). Of course we had edits to make, but his response was positive. After the presentation, Ken said that this information had been there to work with for years, but that no one else had taken the initiative to actually do it.

We had spent the previous two months analyzing a database from the Environmental Protection Agency that describes, in painstaking depth, the current state of spent nuclear fuel in the United States. This fuel is stored in huge containers known in the industry as multi-assembly casks. These casks are the primary units that will be transported in the enormous waste-shipment program that the Department of Energy has been trying to initiate for decades. It was our job to determine the comparative safety of these casks and analyze the connotations of this information in order to help develop a more specific shipment plan. In line with the HLRW’s “oldest fuel first” platform, the age of the casks acted as our main proxy for radioactivity and, therefore, safety.

This analysis is what we’d presented to Mr. Niles. And then, three weeks from our final presentation, we were revisiting our slide deck with one of our mentors, Maury Galbraith. But something felt off that day. We were discussing how to present the importance of cask age and reiterating some of the central questions of our research: What’s the most informative metric for measuring cask age? How do the different strategies compare? And, most important, why is age an effective proxy for level of radioactivity? And it was in that moment, less than a month from our deadline and with a summer’s worth of work behind us, that I had a fascinating realization: it isn’t.

This is not the time or place to discuss the details of why age is an unsatisfactory stand-in for cask safety. It’s overly technical and not the point of this anecdote. For the same reasons, I’m not going to discuss the way which we used fuel age to develop a more complex and effective metric. Instead, I want to talk about the experience of reconceptualizing, restructuring, and redoing a summer’s worth of analysis in two weeks of intensive work.

It was both intimidating and exhilarating to break down an entire concept that I’d worked so many hours on developing. Perhaps the most exciting part was that the idea of using age was not our own. It was the status quo, which we had simply applied to the database. So this was our first chance to approach the problem ourselves. We spent hours discussing and debating different possibilities, and, by the end, we developed a metric that not only worked, but that we understood why it worked. From there our analysis has progressed must faster than we expected. We have been able to produce more relevant results in the past few weeks than we had in the previous seven. The reason for this is simple: the solution fits the problem.

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