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Title: Handling of Uncertainty in WIPP Performance Assessment.


Abstract not provided.

Publication Date:
Research Org.:
Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)
Sponsoring Org.:
USDOE National Nuclear Security Administration (NNSA)
OSTI Identifier:
Report Number(s):
DOE Contract Number:
Resource Type:
Resource Relation:
Conference: Proposed for presentation at the ANS International High-Level Radioactive Waste Management (IHLRWM) Conference 2017 held April 9-13, 2017 in Charlotte, NC.
Country of Publication:
United States

Citation Formats

Zeitler, Todd. Handling of Uncertainty in WIPP Performance Assessment.. United States: N. p., 2017. Web.
Zeitler, Todd. Handling of Uncertainty in WIPP Performance Assessment.. United States.
Zeitler, Todd. Wed . "Handling of Uncertainty in WIPP Performance Assessment.". United States. doi:.
title = {Handling of Uncertainty in WIPP Performance Assessment.},
author = {Zeitler, Todd},
abstractNote = {Abstract not provided.},
doi = {},
journal = {},
number = ,
volume = ,
place = {United States},
year = {Wed Mar 01 00:00:00 EST 2017},
month = {Wed Mar 01 00:00:00 EST 2017}

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  • The Fracture-Matrix Transport (FMT) code developed at Sandia National Laboratories solves chemical equilibrium problems using the Pitzer activity coefficient model with a database containing actinide species. The code is capable of predicting actinide solubilities at 25 C in various ionic-strength solutions from dilute groundwaters to high-ionic-strength brines. The code uses oxidation state analogies, i.e., Am(III) is used to predict solubilities of actinides in the +III oxidation state; Th(IV) is used to predict solubilities of actinides in the +IV state; Np(V) is utilized to predict solubilities of actinides in the +V state. This code has been qualified for predicting actinide solubilitiesmore » for the Waste Isolation Pilot Plant (WIPP) Compliance Certification Application in 1996, and Compliance Re-Certification Applications in 2004 and 2009. We have established revised actinide-solubility uncertainty ranges and probability distributions for Performance Assessment (PA) by comparing actinide solubilities predicted by the FMT code with solubility data in various solutions from the open literature. The literature data used in this study include solubilities in simple solutions (NaCl, NaHCO{sub 3}, Na{sub 2}CO{sub 3}, NaClO{sub 4}, KCl, K{sub 2}CO{sub 3}, etc.), binary mixing solutions (NaCl+NaHCO{sub 3}, NaCl+Na{sub 2}CO{sub 3}, KCl+K{sub 2}CO{sub 3}, etc.), ternary mixing solutions (NaCl+Na{sub 2}CO{sub 3}+KCl, NaHCO{sub 3}+Na{sub 2}CO{sub 3}+NaClO{sub 4}, etc.), and multi-component synthetic brines relevant to the WIPP.« less
  • No abstract prepared.
  • The groundwater flow pathway in the Culebra Dolomite aquifer at the Waste Isolation Pilot Plant (WIPP) has been identified a potentially important pathway for radionuclide migration to the accessible environment. Consequently, uncertainties in the models used to describe flow and transport in the Culebra need to be addressed. A Geostatistics Test Problem'' is being developed to evaluate a number of inverse techniques that may be used for Dow calculations in the WIPP performance assessment (PA). The Test Problem is actually a series of test cases, each being developed as a highly complex synthetic data sct; the intent is for themore » ensemble of these data sets span the range of possible conceptual models of groundwater now at the WIPP site. This paper describes the results from Test Case No. 1. Of the five techniques compared, those based on the linearized form of the groundwater flow equation exhibited less bias and less spread in their GWTT distribution functions; the semi-analytical method had the least bias. While the results are not sufficient to make generalizations about which techniques may be better suited for the WIPP PA (only one test case has been exercised), analyses of the data from this test case provides some indication about the relative importance of other aspects of the flow modeling (besides inverse method or geostatistical approach) in PA. Then ancillary analyses examine the effect of gridding an the effect of boundary conditions on the groundwater travel time estimates.« less
  • Many lessons have been learned over the past 24 years as the Waste Isolation Pilot Plant (WIPP) project has progressed from initial site characterization to final licensing that may be of relevance to other nuclear-waste-disposal projects. These lessons pertain to the manner in which field and laboratory investigations are planned, how experiments are interpreted, how conceptual and numerical models are developed and simplified~ and how defensibility and credibility are achieved and maintained. These lessons include 1) Site characterization and performance assessment (PA) should evolve together through an iterative process, with neither activity completely dominating the other. 2) Defensibility and credibilitymore » require a much greater depth of understanding than can be represented in PA models. 3) Experimentalists should be directly involved in model and parameter abstraction and simplification for PA. 4) External expert review should be incorporated at all stages of a project~ not just after an experiment or modeling activity is completed. 5) Key individuals should be retained for the life of a project or a process must be established to transfer their working knowledge to new individuals. 6) An effective QA program needs to be stable and consistent for the duration of a project and rests on best scientific practices. All of these lessons relate to the key point that consideration must be given from the earliest planning stages to maximizing the defensibility and credibility of all work.« less
  • The Waste Isolation Pilot Plant (WIPP) is being developed by the U.S. Department of Energy (DOE) for the geologic (deep underground) disposal of transuranic (TRU) waste. A Compliance Certification Application (CCA) of the WIPP for such disposal was submitted to the U.S. Environmental Protection Agency (EPA) in October 1996, and was approved by EPA in May 1998. In June 1998, two separate, but related, lawsuits were filed, one against DOE and one against EPA. On March 22, 1999, the court ruled in favor of DOE, and on March 26, 1999, DOE formally began disposal operations at the WIPP for non-mixedmore » (non-hazardous) TRU waste. Before the WIPP can begin receiving mixed (hazardous) TRU waste, a permit from the State of New Mexico for hazardous waste disposal needs to be issued. It is anticipated that the State of New Mexico will issue a hazardous waste permit by November 1999. It is further anticipated that the EPA lawsuit will be resolved by July 1999. Congress (Public Law 102-579, Section 8(f)) requires the WIPP project to be recertified by the EPA at least as frequently as once every five years from the first receipt of TRU waste at the WIPP site. As part of the DOE's WIPP project recertification strategy, Sandia National Laboratories (SNL) has used systems analysis and performance assessment to prioritize its scientific and engineering research activities. Two 1998 analyses, the near-field systems analysis and the annual sensitivity analysis, are discussed here. Independently, the two analyses arrived at similar conclusions regarding important scientific activities associated with the WIPP. The use of these techniques for the recent funding allocations at SNL's WIPP project had several beneficial effects. It increased the level of acceptance among project scientists that management had fairly and credibly compared alternatives when making prioritization decisions. It improved the ability of SNL and its project sponsor, the Carlsbad Area Office of the DOE, to demonstrate the importance of ongoing scientific and engineering activities associated with the WIPP project. Finally, it provided objective documentation of the decision-making process for issues with an impact on safety at the WIPP, a critical topic for the general public and the regulatory agencies.« less