[en] This document describes the monitoring plan to meet the requirements for interim status groundwater monitoring at Hanford Site low-level waste burial grounds as specified by 40 CFR 265, incorporated by reference in WAC 173-303-400. The monitoring will take place at four separate low-level waste management areas in the 200-West and 200-East Areas, in the central part of the site. This plan replaces the previous monitoring plan

[en] This ICN updates the current wells in the monitoring network and replaces Appendix A in the original report.

[en] Xenon is produced as a fission product in nuclear reactors and through spontaneous fission of some transuranic (TRU) isotopes. Xenon gas is nearly inert and will be released from buried TRU waste. This document describes and evaluates the potential for analyzing xenon isotopes in soil gas to detect TRU waste in the subsurface at the Idaho National Environmental and Engineering Laboratory's Radioactive Waste Management Complex

[en] This report documents the results of a PNNL literature review to report on the state of maturity of deep vadose zone remediation technologies for metal contaminants including some radionuclides. Its recommendations feed into decisionmakers need for scientific information and cost-effective in situ remediation technlogies needed under DOE's Environmental Management initiative Enhanced Remediation Methods: Scientific and Technical Basis for In Stu Treatment Systems for Metals and Radionuclides.

[en] Seventy soil gas-sampling points were installed around the perimeter of the 618-11 Burial Ground, approximately 400 feet downgradient of well 699-13-3A, and in four transects downgradient of the burial ground to a maximum distance of 3,100 feet. Soil gas samples were collected and analyzed for helium-3/helium-4 ratios from these 70 points. Helium-3/helium-4 ratios determined from the soil gas sampling points showed significant enrichments, relative to ambient air helium-3 concentrations. The highest concentrations were located along the northern perimeter of the burial ground. Helium-3/helium-4 ratios (normalized to the abundances in ambient air) ranged from 1.0 to 62 around the burial ground. The helium-3/helium-4 ratios from the 4 transect downgradient of the burial ground ranged from 0.988 to 1.68. The helium-3/helium-4 ratios from around the burial ground suggest there is a vadose zone source of tritium along the north side of the burial ground

[en] The subsurface distribution of a nuclear waste tank leak on the U.S. Department of Energy's Hanford Site was sampled by slant drilling techniques in order to characterize the chemical and radiological characteristics of the leaked material and assess geochemical transport properties of hazardous constituents. Sediment core samples recovered from the borehole were subjected to distilled water and acid leaching procedures with the resulting leachates analyzed for isotopic and chemical signatures. High-sensitivity inductively coupled plasma/mass spectrometry (ICP/MS) techniques were used for determination of isotopic ratios for Cs, I, Mo. Analysis of the isotopic patterns of I and Mo combined with associated chemical data showed evidence for at least two separate intrusions of nuclear waste into the subsurface. Isotopic data for Cs was inconclusive with respect to a source attribution signature

[en] Pacific Northwest National Laboratory sampled and analyzed soil gas for helium-3 and helium-4 concentrations from the vicinity of the 618-11 burial ground. The results of the measurement of helium isotopes in soil gas provided a rapid and cost-effective technique to define the shape and extent of tritium contamination from the 618-11 burial ground.

[en] In the mid-1990s, a groundwater plume of uranium (U) was detected in monitoring wells in the B-BX-BY Waste Management Area at the Hanford Site in Washington. This area has been used since the late 1940s to store high level radioactive waste and other products of U fuel-rod processing. Using multiple-collector ICP source magnetic sector mass spectrometry, high-precision uranium isotopic analyses were conducted of samples of vadose zone contamination and of groundwater. The isotope ratios 236U/238U, 234U/238U, and 238U/235U are used to distinguish contaminant sources. On the basis of the isotopic data, the source of the groundwater contamination appears to be related to a 1951 overflow event at tank BX-102 that spilled high-level U waste into the vadose zone. The U isotopic variation of the groundwater plume is a result of mixing between contaminant U from this spill and natural background U. Vadose zone U contamination at tank B-110 likely predates the recorded tank leak and can be ruled out as a significant source of groundwater contamination, based on the U isotopic composition. The locus of vadose zone contamination is displaced from the initial locus of groundwater contamination, indicating that lateral migration in the vadose zone was at least 8 times greater than vertical migration. The time evolution the groundwater plume suggests an average U migration rate of ∼0.7-0.8 m/day showing slight retardation relative a groundwater flow of ∼1 m/day

[en] Groundwater is monitored at the Hanford Site to fulfill a variety of state and federal regulations, including the Atomic Energy Act of 1954; the Resource Conservation and Recovery Act of 1976; the Comprehensive Environmental Response, Compensation, and Liability Act of 1980; and Washington Administrative Code. Separate monitoring plans are prepared for various requirements, but sampling is coordinated and data are shared among users to avoid duplication of effort. The U.S. Department of Energy manages these activities through the Hanford Groundwater Monitoring Project. This document is an integrated monitoring plan for the groundwater project. It documents well and constituent lists for monitoring required by the Atomic Energy Act of 1954 and its implementing orders; includes other, established monitoring plans by reference; and appends a master well/constituent/ frequency matrix for the entire site. The objectives of monitoring fall into three general categories: plume and trend tracking, treatment/ storage/disposal unit monitoring, and remediation performance monitoring. Criteria for selecting Atomic Energy Act of 1954 monitoring networks include locations of wells in relation to known plumes or contaminant sources, well depth and construction, historical data, proximity to the Columbia River, water supplies, or other areas of special interest, and well use for other programs. Constituent lists were chosen based on known plumes and waste histories, historical groundwater data, and, in some cases, statistical modeling. Sampling frequencies were based on regulatory requirements, variability of historical data, and proximity to key areas. For sitewide plumes, most wells are sampled every 3 years. Wells monitoring specific waste sites or in areas of high variability will be sampled more frequently

[en] This paper describes soil-gas sampling for the rare gases helium and xenon that can be used to define the locations of tritium and transuranic waste. Soil-gas sampling is a minimally invasive technique, in that direct penetration of the waste is not required and no hazardous material is brought to the surface