Characterization of Direct Push Vadose Zone Sediments from the 241-U Single-Shell Tank Farm

Technical Report · Thu Dec 20 00:00:00 EST 2007

DOI:https://doi.org/10.2172/923689· OSTI ID:923689

Brown, Christopher F; Valenta, Michelle M; Serne, R Jeffrey; Bjornstad, Bruce N; Lanigan, David C; Iovin, Cristian; Clayton, Ray E; Geiszler, Keith N; Clayton, Eric T; Kutnyakov, Igor V; Baum, Steven R; Lindberg, Michael J; Orr, Robert D

The overall goals of the Tank Farm Vadose Zone Project, led by CH2M HILL Hanford Group, Inc., are 1) to define risks from past and future single-shell tank farm activities, 2) to identify and evaluate the efficacy of interim measures, and 3) to aid, via collection of geochemical information and data, the future decisions that must be made by the U.S. Department of Energy (DOE) regarding the near-term operations, future waste retrieval, and final closure activities for the single-shell tank Waste Management Areas (WMAs). For a more complete discussion of the goals of the Tank Farm Vadose Zone Project, see the overall work plan, Phase 1 RCRA Facility Investigation/Corrective Measures Study Work Plan for the Single-Shell Tank Waste Management Areas (DOE 1999). Specific details on the rationale for activities performed at WMA U are found in Crumpler (2003). To meet these goals, CH2M HILL Hanford Group, Inc., asked scientists from Pacific Northwest National Laboratory (PNNL) to perform detailed analyses of vadose zone sediment collected within the U Single-Shell Tank Farm. Specifically, this report contains all the geochemical and selected physical characterization data collected on vadose zone sediment recovered from ten direct push characterization holes emplaced to investigate vadose zone contamination associated with potential leaks within the 241-U Single-Shell Tank Farm. Specific tanks targeted during this characterization campaign included tanks 241-U-104/241-U-105, 241-U-110, and 241-U-112. Additionally, this report compiles data from direct push samples collected north of tank 241-U-201, as well as sediment collected from the background borehole (C3393). After evaluating all the characterization and analytical data, there is no question that the vadose zone in the vicinity of tanks 241-U-104 and 241-U-105 has been contaminated by tank-related waste. This observation is not new, as gamma logging of drywells in the area has identified uranium contamination at the same depths interrogated by push hole C5602. Given that the deepest sample string analyzed from push hole C5602 contained trace activities of technetium-99, it is obvious that tank waste contamination has impacted the vadose zone to at least a depth of 92 ft bgs at this location. However, the scope of the sampling campaign was to acquire additional samples to better understand the aerial extent of contamination in the U Tank Farm; therefore, future characterization activities (i.e., a borehole) will be required to understand the total vertical depth of contamination at this location.

• Research Organization: Pacific Northwest National Lab. (PNNL), Richland, WA (United States)
• Sponsoring Organization: USDOE
• DOE Contract Number: AC05-76RL01830
• OSTI ID: 923689
• Report Number(s): PNNL-17163; 830403000; TRN: US0802046
• Country of Publication: United States
• Language: English

Related Subjects

12 MANAGEMENT OF RADIOACTIVE WASTES, AND NON-RADIOACTIVE WASTES FROM NUCLEAR FACILITIES
BOREHOLES
CLOSURES
CONTAMINATION
GAMMA LOGGING
SAMPLING
SEDIMENTS
STORAGE FACILITIES
TANKS
TECHNETIUM 99
URANIUM
WASTE MANAGEMENT
WASTE RETRIEVAL
WASTES
tank farm
Hanford Site
tank waste
single-shell tank
vadose zone
CH2M Hill