Identification of issues relevant to the first recertification of WIPP

Technical Report · Mon Sep 30 00:00:00 EDT 2002

DOI:https://doi.org/10.2172/1184374· OSTI ID:1184374

Allen, Lawrence E. ^[1]; Silva, Matthew K. ^[1]; Channell, James K. ^[1]

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1. Environmental Evaluation Group, Albuquerque, NM (United States)

One goal of the WIPP Land Withdrawal Act was to assure the safe disposal of the nation’s defense transuranic waste into a deep repository in southeast New Mexico. The governing legislation required the U.S. Department of Energy (DOE) to provide to the U.S. Environmental Protection Agency (EPA) analyses of the anticipated performance of the repository. Disposal operations could not begin until the EPA determined that the project demonstrated compliance with EPA Standards (40 CFR 191) and EPA Criteria (40 CFR 194) for such disposal. The Land Withdrawal Act inherently recognized that the EPA Certification would have to rely on best available knowledge at the time when the application was submitted. The Act also recognized that after the initial certification of WIPP and start of disposal operations, operating experience and ongoing research would result in new technical and scientific information. Thus, the legislation requires recertification of the WIPP every five years, following the first receipt of waste. This report updates issues that the Environmental Evaluation Group (EEG) considers important as the Department of Energy (DOE) works towards the first recertification. These issues encompass a variety of technical areas including actinide solubility, fluid injection scenarios, solution mining, Culebra flow and transport, spallings modeling, and non-random waste emplacement. Given the 24,000-year half life of ²³⁹Pu, understanding the characteristics of plutonium in the WIPP environment is obviously important to the validity of long-term performance assessment of the repository. Some uncertainty remains in the understanding of the persistence of higher oxidation states because of reliance on modeling (with its associated assumptions) and limited experimental results. The EEG recommends additional experimental work towards parameters for a proposed conceptual kinetic model of plutonium solubility. In addition, the EEG recommends an intrusion scenario during performance assessment which would account for a heterogeneous, non-inundated repository which may include persisting higher oxidation states of plutonium.

• Research Organization: Environmental Evaluation Group, Albuquerque, NM (United States)
• Sponsoring Organization: USDOE
• Contributing Organization: CEHMM, Carlsbad, NM (United States)
• DOE Contract Number: AC04-79AL10752; AC04- 89AL58309
• OSTI ID: 1184374
• Report Number(s): EEG-83; DOE/AL/58309-83
• Country of Publication: United States
• Language: English