The Nuclear Energy and Nuclear Waste Program has been established within the Earth and Environmental Sciences Area’s Energy Resources Program Area of LBNL. The research activities are largely supported by the U.S. DOE Office of Nuclear Energy and the U.S. Nuclear Regulatory Commission, with additional funding coming from a variety of domestic and international sponsors. Many activities reside within DOE’s Spent Fuel & Waste Science and Technology (SFWST) Campaign, which was formerly called Used Fuel Disposition (UFD) Campaign. The SFWST research addresses the need for secure disposal of the high-level radioactive waste that has been produced from nuclear power generation (and weapons production) across the world.
Berkeley Lab scientists made key contributions to the research and licensing activities aimed at the investigations of the deep geological disposal of nuclear waste in unsaturated tuff formation at the proposed Yucca Mountain repository in Nevada. Berkeley Lab scientists are currently leading research and technology development to enable long-term radioactive waste disposal in other host-rock environments, such as argillite/shale, salt rock, and crystalline rock, and alternative repository designs.
The research is focused on studies of the complex coupled subsurface processes–thermal, hydrological, mechanical, and chemical (THMC), which will be triggered by perturbations from the repository construction, engineered barrier emplacement, and waste disposal. Advanced numerical modeling methods for evaluating and predicting these coupled processes are being developed and tested against experiments conducted at multiple laboratory and field scales, from micro-scale imaging of clay swelling and clay rock damage in laboratory settings to large in situ experiments conducted in Underground Research Laboratories (URLs). THMC studies are critical for the evaluation of the potential long-term impacts on repository site safety. For example, temperature rise from radioactive decay may trigger an increase in pore pressure , mechanical deformations, and chemical reactions, possibly causing rock damage and mineralogical changes, which could strongly affect radionuclide transport. Without the ability to predict the long-term consequences of these early-stage subsurface perturbations, it is difficult to assess whether natural and engineered barriers would provide safe disposal options over thousands to millions of years.
Spent Fuel & Waste Science and Technology (SFWST) Campaign (formerly called Used Fuel Disposition (UFD) Campaign) was initiated in 2009. Its mission is “To identify alternatives and conduct scientific research and technology development to enable storage, transportation and disposal of used nuclear fuel and wastes generated by existing and future nuclear fuel cycles.” In disposal R&D, ‘activities continue to further the understanding of long-term performance of disposal systems in three main geologic rock types: clay/shale, salt, and crystalline rock. These activities include collaborations with international partners to leverage and integrate applicable R&D being conducted by other countries into the U.S. disposal R&D portfolio. Evaluations will be completed to determine the feasibility of directly disposing existing single (storage only) and dual purpose (storage and transportation) spent fuel canisters in a mined repository.” Research work in LBNL’s NE&NW program is funded mostly by SFWST, and includes a wide variety of research topics, ranging from fundamental understanding of the coupled processes at pore-scale to coupled thermal, hydrological, mechanical and chemical (THMC) modeling of in-situ repositories in argillite, crystalline and salt formations.. While advancing scientific understanding of underground processes related to long-term nuclear waste disposal, we are also developing cutting-edge experimental and modeling tools and methodologies.
For SFWST, international collaboration is a beneficial and cost-effective strategy with regards to multiple disposal options and different geologic environments. While the U.S. disposal program focused solely on Yucca Mountain tuff as host rock over the past decades, several international programs have made significant progress in the characterization and performance evaluation of other geologic repository options, most of which are very different from the Yucca Mountain in design and host rock characteristics. Because Yucca Mountain was so unique (e.g., no backfill, unsaturated densely fractured tuff), areas of direct collaboration with international disposal programs were quite limited during that time.
The decision by the U.S. Department of Energy to no longer pursue the disposal of high-level radioactive waste and spent fuel at Yucca Mountain has shifted DOE’s interest to disposal options and geologic environments similar to those being investigated by nuclear waste disposal programs in other nations. Much can be gained by close collaboration with these programs, including access to valuable experience and data collected over recent decades at several operating underground research laboratories (URLs). Particularly, the UFD scientists have been working closely with international scientists on concrete research projects relevant to both sides — opportunities for active international collaboration (.pdf).Such active collaboration has provided direct access to information, data, and expertise on various disposal options and geologic environments that have been collected over the past decades. Many international programs have URLs in clay/shale, granite, and salt environments, in which relevant field experiments have been and are being conducted.
To advance collaboration, Dr. Jens Birkholzer of LBNL serves as UFD’s Technical Lead for International Activities, and advises UFD on international opportunities that complement ongoing R&D within the campaign, and helps identify those activities that provide the greatest potential for substantive technical advances.
Workshop on the Fifth Worldwide Review “Challenging Issues in Deep Geologic Disposal of Nuclear Wastes”
To facilitate the sharing of knowledge about the isolation of nuclear waste in various rock types—as well as any other information related to nuclear waste isolation—in 1991, Paul Witherspoon initiated publication of a series of worldwide reviews describing the progress made by various countries around the world in their nuclear waste isolation programs. Thes reviews were published in conjunction with workshops, including the most recent 2016 Worldwide Review. LBNL hosted the Fifth Worldwide Review (WWR-5) Workshop on nuclear waste disposal in geological formations on May 25-26, 2016. The overall objective of the WWR-5 Workshop was to summarize the experience and lessons learned documented in the Fifth Worldwide Review Report, and to establish future cooperation/collaboration between the participating countries pursuing geological disposal programs. The Workshop included oral presentations of the countries, followed by group discussions of the materials. The materials of the group discussions were included in the final edition of the Fifth Worldwide Review report (see all Worldwide Review reports). In particular, the presentations at the WWR-5 Workshop included the following types of information: the current status of the deep geological repository programs for high nuclear waste and low- and intermediate nuclear waste and in each of the countries, concepts of siting and radioactive waste and spent nuclear fuel management in different countries (with the emphasis of nuclear waste disposal under different climatic conditions and different geological formations), progress in repository site selection and site characterization, technology development, buffer/backfill materials studies and testing, support activities, programs, and projects, international cooperation, and future plans, as well as regulatory issues and transboundary problems. (See: Fifth Worldwide Review Report Online; Fifth Worldwide Review Workshop; OSTI/Complete WWR-5 Report; LBNL Blog (2017))
Coupled thermo-hydro-mechanical-chemical (THMC) processes in geological systems are critically important to the performance and safety assessment of geologic disposal systems for radioactive waste and spent nuclear fuel. Understanding of such processes is also essential for a number of other subsurface engineering processes, including mining, geothermal exploration, geological carbon sequestration, energy storage, and oil and gas production. The DECOVALEX 2019 Symposium on Coupled Processes in Radioactive Waste Disposal and Subsurface Engineering Applications invites you to the beautiful city of Brugg, Switzerland, November 4-5, 2019. Located about 28 kilometers from Zürich, Brugg is known for its historic center developed along a narrow gorge of the river Aare. This open symposium will feature internationally recognized keynote speakers and researchers focusing on coupled processes, including computational methods, lab experiments, and in situ tests. The symposium will also provide exciting insights from the current phase of the DECOVALEX project, an international collaboration for advancing the understanding of coupled THMC processes in a geological system.