Used fuel disposition research and development roadmap - FY10 status.

Abstract

SUMMARYSince 1987 the U.S. has focused research and development activities relevant to the disposal of commercial used nuclear fuel and U.S. Department of Energy (DOE) owned spent nuclear fuel and high level waste on the proposed repository at Yucca Mountain, Nevada. At the same time, the U.S. successfully deployed a deep geologic disposal facility for defense-related transuranic waste in bedded salt at the Waste Isolation Pilot Plant.In 2009 the DOE established the Used Fuel Disposition Campaign (UFDC) within the Office of Nuclear Energy. The Mission of the UFDC isTo 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.The U.S. national laboratories have participated on these programs and has conducted research and development related to these issues to a limited extent. However, a comprehensive research and development (R&D) program investigating a variety of geologic media has not been a part of the U.S. waste management program since the mid 1980s. Such a comprehensive R&D program is being developed in the UFDC with a goal of meeting the UFDC Grand Challenge. To provide a sound technical basis for absolute confidence in the safety and security of long-term storage, transportation, and disposal of used nuclear fuel and wastes from the nuclear energy enterprise.The DOE has decided to no longer pursue the development of a repository at Yucca Mountain, Nevada. Since a repository site will ultimately have to be selected, sited, characterized, designed, and licensed, other disposal options must now be considered. In addition to the unsaturated volcanic tuff evaluated at Yucca Mountain, several different geologic media are under investigation internationally and preliminary assessments indicate that disposal of used nuclear fuel and high level waste in these media is feasible. Considerable progress has been made in the U.S. and other nations in understanding disposal concepts in different geologic media, but gaps in knowledge still exist.A principal aspect of concern to the UFDC as it considers the broad issues of siting a repository in different geologic media are the marked differences in the regulatory bases for assessing suitability and safety of a repository between the U.S. and other nations. Because the probability based -risked informed nature of the current U.S. regulations for high-level radioactive waste and spent nuclear fuel is sufficiently different from other regulations, information gained in previous studies, while useful, likely need to be supplemented to enable more convincing communication with the public, better defense of the numerical models, and stronger safety cases.Thus, it was recognized when the UFDC was established that there were readily identified disposalrelated R&D opportunities to address knowledge gaps.. An effort to document these research opportunities was a key component of Fiscal Year (FY) 2010 engineered system, natura...

A multiphase interfacial model for the dissolution of spent nuclear fuel

“…2 shows that the Eh threshold for the oxidative dissolution of UO 2 decreases from around 0.05 to À0.18 V with a pH increase from 7 to 10, and that the aqueous speciation of U(VI) changes with pH. At pH 7, the dominant species are (UO 2 ) 2 CO 3 (OH) 3 À and UO 2 (CO 3 ) 2 2 (curves a and b in Fig. 2), whereas at pH 10 the dominant species are UO 2 (CO 3 ) 3 4À and UO 2 (OH) 3 À (curves e and f in Fig.…”

“…For example, in the U.S. there is approximately 23 billion curies of long-lived radioactivity in commercial used oxide fuel stored at 75 sites in 33 states [1]. The direct disposal of existing inventories of used oxide fuel in geologic repositories is a primary waste management strategy throughout the global community [2,3]. Used fuel destined for direct disposal in a repository is referred to as ''spent fuel'' in this paper.…”

Disposal R&D in the Used Fuel Disposition Campaign: A Discussion of Opportunities for Active International Collaboration

“…EBS-related R&D items have also been considered in previous progress reports (e.g., Jove-Colon et al, 2010). All R&D gaps identified in these reports have been evaluated in consideration of their importance to the safety case in a recently conducted roadmap exercise (Used Fuel Disposition Campaign Disposal Research andDevelopment Roadmap, FCRD-USED-2011-000065 Rev 0, March 2011;Tables 7 and 8; [Nutt, 2011] [Nutt, 2011]). Section 6 describes other options for international collaboration; i.e., options that may not require formal "membership", but may rather be facilitated via direct informal or semi-formal agreements between national laboratories and international partners.…”

Establishment of Research and Development Priorities Regarding the Geologic Disposal of Nuclear Waste in the United States and Strategies for International Collaboration

“…UFDC researchers are actively pursuing opportunities for such collaboration. The UFDC has issued the initial Used Fuel Disposition Campaign International Activities Implementation Plan 10 , continues to mature its international collaboration strategy, and is beginning the execution of international collaborative activities. International geologic disposal programs are at various different states, ranging from essentially "no progress" to selected sites and pending license applications to regulators.…”