PNNL Researchers Earn Distinguished Honors at Waste Management Symposia

A team of Pacific Northwest National Laboratory (PNNL) researchers has earned a 2026 Papers of Note award at this year’s Waste Management Symposia (WMS), one of the conference’s highest manuscript distinctions. Led by computational scientist Tim C. Johnson, the award-winning research brought together expertise in environmental modeling, subsurface science, and artificial intelligence—including key contributions from postdoctoral researcher José Luis Hernandez Mejia, who will join PNNL as a full-time staff member this fall.

Their paper, “Generative AI for Calibrating Subsurface Remediation Simulators Using Time-Lapse Electrical Resistivity Tomography,” was recognized as both a 2026 Papers of Note award recipient and a Superior Paper, placing it among the conference’s most distinguished research contributions. PNNL coauthors of this paper include Glenn Hammond, Piyoosh Jaysaval, and Rob Mackley.

Their paper demonstrates how generative artificial intelligence can improve calibration of subsurface remediation models, helping researchers better predict and manage contamination at legacy waste sites.

“The decisions that drive environmental cleanup depend on groundwater models, but those models have always been limited by sparse data,” Johnson said. “By bringing AI together with geophysical information, we can better characterize the subsurface and make more reliable predictions about where contaminants will go and how cleanup efforts will perform. José was the technical force behind the AI that made it work, and we’re making great strides toward solving a longstanding challenge.”

Hernandez Mejia developed the project’s generative AI approach using field observations, including time-lapse electrical resistivity data, to estimate subsurface properties that are difficult to measure directly. The AI model generates parameter sets that match observed conditions, helping researchers build more accurate groundwater and contaminant transport models.

“I really enjoy the work I do here, especially applying AI and data science to challenges,” said Hernandez Mejia. “This recognition reflects a true team effort, and I’ve learned a tremendous amount from everyone involved.”

Another PNNL researcher, Jared Oshiro, was recognized with a Papers of Note award and a Superior Paper award for coauthoring “A Method for Direct Vitrification of Fukushima Waste Drums by GeoMelt® In-Container Vitrification (ICV)™,” alongside Kevin Finucane from Veolia. Following the 2011 Fukushima Daiichi Nuclear Power Station disaster—caused by a major earthquake and a 15-meter tsunami that led to the core melting of three reactors—Veolia, supported by PNNL, has played a key role in supporting radioactive waste cleanup efforts. 

The paper presents engineering-scale evidence demonstrating that Veolia’s GeoMelt® ICV™ technology can streamline and enhance the treatment of Fukushima’s radioactive waste. By directly converting large volumes of waste into a stable glass form, this approach has the potential to reduce processing complexity and improve the safety of long-term disposal.

“It was an honor to be involved with the professional partnership between Veolia and PNNL,” said Oshiro. “This publication demonstrates the potential of Veolia’s GeoMelt® ICV™ and how as an independent research lab, PNNL can play a critical role in helping mature these technologies.”

WM Symposia, Inc. is a nonprofit organization that provides an international forum to share radioactive waste management solutions and nuclear facility decommissioning processes. The annual conference covers cross-cutting topics such as robotic handling; remote systems; new technologies; radioactive and hazardous waste characterization, treatment, storage, packaging, transportation, and disposal; engineering design and construction; environmental laboratories; decontamination; decommissioning; and environmental remediation. 

Superior Papers showcase broad research expertise

In addition to the two Papers of Note honors, PNNL researchers contributed to another eight papers recognized by WMS as Superior Papers, six of those as the lead author and two as the coauthor. WMS selects Superior Papers for demonstrating technical rigor, clarity of communication, mission relevance, innovation, and evidence-based impact.

• “Corrosion and Development of Bubbler Alloys for Joule Heated Ceramic Melters.” WM#26034. Authors: Jarrod Crum, Jared Oshiro, Nathan Canfield, Ron Brown, Jesse Lang, Derek Dixon, Mark Hall, Mageshwari Komarasamy, William Eaton, and Nicholas Ruehle, PNNL; Albert Kruger, Department of Energy (DOE) Hanford Field Office (HFO).
• “Hanford West Area Tank Treatment Solids Assessment.” WM#26037. Authors: Amy Westesen, Carolyn Burns, and Reid Peterson, PNNL; David Blumenkranz, Hanford Tank Waste Operations & Closure (H2C).
• “Alternate Reductants for Mitigating Acetonitrile During Vitrification of Hanford Tank Waste.” WM#26042. Authors: Jessica Rigby, José Marcial, Jesse Lang, Derek Dixon, Ron Brown, Jared Oshiro, Mark Hall, and William Eaton, PNNL; Albert Kruger, DOE HFO.
• “Potential for Natural Attenuation of Nitrate at the Hanford Nuclear Site.” WM#26051. Authors: Gemma Clark, Matthew Asmussen, Guohui Wang, Elsa Cordova, Andy Plymale, and Gary L. Smith, PNNL.
• “A Hybrid Recalibration Framework for Deep Learning Models in Groundwater Remediation: Enhancing Long-Term Predictive Accuracy at Legacy Waste Sites.” WM#26538. Authors: Xuehang Song, Steve Eklund, Tse-Chun Chen, Yilin Fang, Zhangshuan Hou, Grigoriy Kondyukov, Xiaoliang (Bryan) He, Mark Rockhold, Inci Demirkanli, and Ruoshi Cao, PNNL.
• “Corrosion Testing and Model Development for Next Generation Multiphase Waste Forms.” WM#26539. Authors: Matthew Asmussen, Gary L. Smith, Benjamin Parruzot, Sebastien Kerisit, Jesse Westman, Ian Burch, and Joelle Reiser, PNNL; Phillip Sutton, Eugenia Kuo, Luiz Bortolan Neto, and Dan Gregg, ANSTO.
• “Update on Developing Solutions for Dry Retrieval of Hanford Tank Waste Year 2: Focus on Waste Translation.” WM#26119. Authors: David Mascarenas, Andre Green, Thanatat Thanaravisara, Jacob Piper, Moises Mello Felipe de Silva, Ty Schnepper, and Evelyn Fernandez, Los Alamos National Laboratory; Carl Enderlin and Brandon Hager, PNNL; Alex Cozzi and Marisa Moss, Savannah River National Laboratory.
• “Status of the US DOE’s Plans and Preparations for Transporting the High Burnup Research Cask of Used Nuclear Fuel in 2027.” WM#26464. Authors: Erica Bickford and Sara Hogan, DOE Office of Nuclear Energy; Gordon Petersen, Idaho National Laboratory; Kevin Connolly, Oak Ridge National Laboratory; Miriam Juckett, PNNL.

Additional WMS Leadership

Beyond paper recognitions, two PNNL researchers were appointed to the WMS Program Advisory Committee, contributing thought leadership to the development of topics and program areas. Steve Maheras, a nuclear engineer, was elected to cochair and serve on Track 5, which focuses on providing opportunities for continuous improvement in transporting radioactive material. Hilary Emerson, an Earth scientist, was elected to serve on Track 10, which focuses on the role of education and training programs in preparing the next generation of professionals for careers in nuclear waste management and related fields. For a full list of PAC members, please visit the WMS site.

The next WMS conference will be held March 7–11, 2027, at the Phoenix Convention Center in Phoenix, AZ.