A Quantitative Risk Assessment Perspective on the Source Term for the Proposed Nuclear Waste Repository at Yucca Mountain

2009 ◽  
Vol 1193 ◽  
Author(s):  
William M. Murphy ◽  
B. John Garrick ◽  
Bruce E. Kirstein
Keyword(s):  
Risk Assessment ◽  
Nuclear Waste ◽  
Source Term ◽  
Initial Conditions ◽  
Yucca Mountain ◽  
Quantitative Risk Assessment ◽  
Nuclear Waste Repository ◽  
Event Tree ◽  
Geologic Repository ◽  
Isolation System

AbstractA quantitative risk assessment methodology is outlined for the source term for the proposed geologic repository for high-level nuclear waste at Yucca Mountain, Nevada. The methodology involves construction of a logical event tree to identify scenarios for the success or failure of the waste isolation system. Uncertainties in the intervening events between initial conditions and consequences can be quantified using probability distributions for steps along each scenario path. Likelihood is quantified according to the frequencies for each split fraction in the event tree. The result is a calculated probability of frequency curve for the release rate(s) of the modeled radionuclide(s).

Source-Term Constraints for the Proposed Repository at Yucca Mountain, Nevaida, Derived from the Natural Analog at PeÑa Blanca, Mexico

1991 ◽  
Vol 257 ◽  
Author(s):  
William M. Murphy ◽  
English C. Pearcy
Keyword(s):  
Nuclear Waste ◽  
Source Term ◽  
Yucca Mountain ◽  
Performance Assessments ◽  
Nuclear Waste Repository ◽  
Advective Transport ◽  
Silicate Minerals ◽  
Natural Analog ◽  
Rate Limiting ◽  
Nuclear Waste Forms

ABSTRACTThe source term for nuclear waste repository performance assessments can be constrained by the solubilities of radioelement-bearing solids and/or the rates of release of radioelements from nuclear waste forms. Both solubility and rate limits for the proposed repository at Yucca Mountain, Nevada, can be assessed using information from the natural analog at PeÑa Blanca, Mexico. Petrographic and field relations indicate that uraninite oxidation and transformation to secondary uranyl silicate minerals have been rapid relative to mass transport of uranium out of the PeÑa Blanca system. The rate limiting process for uranium removal is likely to be advective transport in groundwaters with uranium contents controlled by interactions with uranyl silicate minerals such as uranophane. A maximum limit on the rate of uraninite oxidation at PeÑa Blanca is calculated to be 0.032 tons of UO2 per year using geologic constraints on the amount of oxidation and the available time.

Experimental Investigation of Hydrous Pyrolysis of Diesel Fuel and the Effect of Pyrolysis Products on Performance of the Candidate Nuclear Waste Repository at Yucca Mountain

1993 ◽  
Vol 333 ◽  
Author(s):  
Kenneth J. Jackson ◽  
Susan A. Carroll
Keyword(s):  
Experimental Investigation ◽  
Nuclear Waste ◽  
Diesel Fuel ◽  
Yucca Mountain ◽  
Nuclear Waste Repository ◽  
Hydrothermal Solutions ◽  
Pyrolysis Products ◽  
Analytical Technique ◽  
Hydrous Pyrolysis ◽  
Waste Repository

It is thought that a significant amount of diesel fuel and other hydrocarbon-rich phases may remain inside the candidate nuclear waste repository at Yucca Mountain after construction and subsequent emplacement of radioactive waste. Although the proposed repository horizon is above the water table, the remnant hydrocarbon phases may react with hydrothermal solutions generated by high temperature conditions that will prevail for a period of time in the repository. The preliminary experimental results of this study show that diesel fuel hydrous pyrolysis is minimal at 200°C and 70 bars. The composition of the diesel fuel remained constant throughout the experiment and the concentration of carboxylic acids in the aqueous phases was only slightly above the detection limit (1–2 ppm) of the analytical technique.

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