No abstract

Extensive geomorphic mapping in the northern Martian fretted terrain of Deuteronilus and Protonilus Mensae shows details of the wastedominated landform association in this region. Wasting appears to have occurred along the cratered terrain boundary (CTB) at the expense of old cratered terrain. North of the boundary remnants of old cratered terrain occur as island mesas surrounded by extensive debris aprons. Quantitative study using principal components analysis (PCA) reveals distinct spatial variations in the morphology of waste forms in the egion and supports the qualitative interpretations made during geomorphic mapping. These organized spatial patterns occur with respect to longitude and latitude, and therefore with reference to distance from the CTB, and provide clues to the degradational history of the region. Analyses of the individual landforms irrespective of their location to the CTB indicate strong structural control of their form. Mesas appear to evolve from equant forms to narrow ridges with large debris aprons after they become detached from the old cratered terrain. The success of PCA in explaining patterns in degradational landforms suggests that PCA may be an important technique in quantifying the geomorphic evolution of the Martian surface.

Regional geology and indoor radon concentrations appear to be related in the US. Using data from probability based samples, indoor radon frequency distributions have been developed in areas with similar regional geology. These frequency distributions can be used to define relative radon potential in the US. The geologic factors which determine regional radon potential are: (1) Lithologic: Rock types with known or potentially high uranium concentrations have a high probability of generating elevated indoor radon levels. Lithologies with US DOE National Uranium Resource Evaluation (NURE) equivalent uranium concentrations greater than 3 ppm may constitute high radon potential areas. (2) Soils: Soil permeability greatly influences radon potential. For Example, evidence suggests that high permeabilities (>0.01 cm.s-1) can cause elevated indoor radon levels even if radium concentrations are low.

In March of 1999, the Waste Isolation Pilot Plant (WIPP) in southeast New Mexico, the world's first deep geological repository for radioactive materials, began receiving defense-related transuranic waste. The WIPP was designed and constructed by the U.S. Department of Energy, but critical to its opening was certification by the U.S. Environmental Protection Agency that the repository complies with the radioactive waste disposal regulations set forth as environmental radiation protection standards (40 CFR Part 191) and compliance criteria (40 CFR Part 194). This paper provides a summary of the regulatory process, including the Environmental Protection Agency's waste containment, groundwater protection, and individual dose regulations for the WIPP; the Department of Energy's performance assessment and the other parts of its compliance certification application; and the Environmental Protection Agency's review and analysis of the compliance certification application and related documentation.

The U.S. Environmental Protection Agency (EPA or the Agency) developed environmental standards for the disposal of defense-related transuranic wastes for the U.S. Department of Energy’s (DOE or the Department) Waste Isolation Pilot Plant (WIPP). EPA implements these standards for WIPP, which has been in operation for over ten years. The general environmental standards are set forth in the Agency’s 40 CFR Part 191 Environmental Radiation Protection Standards for the Management and Disposal of Spent Nuclear Fuel, High-Level and Transuranic Radioactive Wastes [1]. These standards are implemented by site-specific compliance criteria [2]. The WIPP Land Withdrawal Act requires DOE to submit a re-certification application every five years after the initial receipt of waste. DOE submitted the latest WIPP re-certification application in March 2009. For re-certification, DOE must identify changes that have occurred over the previous five years and analyze their impact on the potential long-term performance of the repository. Once EPA determines that the re-certification application is complete, the Agency has six months to review the application and make a final decision. During this review, EPA solicits and incorporates public comment where appropriate. During the first re-certification in 2004, several stakeholder groups brought up issues (e.g., karst) that were addressed in the original certification. EPA has received comments again raising some of these same issues for the 2009 re-certification. In addition, DOE must submit proposed changes to the WIPP repository to EPA for review and approval. This paper describes selected issues of concern to WIPP and highlights interactions between EPA as the regulatory authority and DOE as the implementing organization. In general EPA’s experience points out the importance of communication, documentation and the regulator’s responsibility in determining “how much is enough.”