Sandia National Laboratories performance assessment methodology for long-term environmental programs : the history of nuclear waste management.

Performance assessment for climate intervention (PACI): preliminary application to a stratospheric aerosol injection scenario

“…WIPP is owned by the United States Department of Energy (DOE) and is subject to waste containment requirements defined by Title 40 of the United States Code of Federal Regulations (CFR) §191.13. As required by 40 CFR 191.13, a PA framework was developed for the WIPP to demonstrate a reasonable expectation that the probabilities of cumulative radionuclide releases from the disposal system during the 10,000 years following closure will fall below specified limits (Meacham et al, 2011).…”

“…Though now closed, the Yucca Mountain Project (YMP) was a proposed deep geological repository storage facility for spent nuclear fuel and other high-level radioactive waste in the United States. Before the YMP was defunded in 2011, a Total System Performance Assessment (TSPA) was developed on behalf of the DOE to support the YMP site recommendation and license application process (Meacham et al, 2011). Like the WIPP, the YMP was subject to requirements defined by 10 CFR 63, which states (among other requirements) that there must be a reasonable expectation that for 10,000 years following disposal from all pathways, the "reasonably maximally exposed individual" would receive no more than the stated dose equivalent, and that releases of radionuclides to the accessible environment will not exceed specified limits.…”

“…The PA framework has previously been utilized for its ability to encompass the complexities and large timescales important to ensuring the integrity of the disposal facility and safety to the public and the environment. This framework has been applied beyond the nuclear waste disposal community, a generic nuclear waste disposal PA framework is summarized in Lowry (2021) (modified from Meacham et al, 2011). For instance, Lowry (2021) applied the PA framework to a geothermal energy project to identify pathways for reducing or eliminating underlying risks and though not a direct application of the PA, McKinley et al (2022) outlines a risk assessment approach originating with the approaches and tools for radioactive waste disposal to the risk management associated with climate change, citing similarities between the two problems with respect to timescale, multidisciplinary nature, and need to enhance public understanding and political buy-in, among others.…”

“…Key components of a PA framework include identifying performance goals, identifying the extent of the system under study, and then identifying which FEPs are relevant and impactful to calculating model output for the system given the performance goals identified. At that point, the performance of the system (including various forms of uncertainty) can be evaluated against the performance goal (Meacham et al, 2011). The regulations governing a PA, the FEPs under consideration, and the final included models are iterated to build confidence that the technical basis is sound and defensible, and that the PA results illustrate the range of possible future outcomes (Galson et al, 2000).…”

“…If the deployment of SAI is ever seriously considered, policymakers will require tools to facilitate informed decision making in support of regional interests, geopolitical stability, and future regulations. A precedent for a decision making framework for such a multifaceted problem already exists for nuclear waste disposal, called Performance Assessment (PA) (Meacham et al, 2011). The similarities between radioactive waste disposal and climate change, and the opportunities for modifying and applying the tools developed in the radioactive waste disposal community to climate change has been suggested previously by McKinley et al (2022).…”