Results for “Monitoring” — Page 15

DOE OSTI2019

Tonopah Test Range Air Monitoring: CY2018 Meteorological, Radiological, and Wind Transported Particulate Observations

In 1963, the U.S. Department of Energy (DOE) (formerly the Atomic Energy Commission [AEC]), implemented Operation Roller Coaster on the Tonopah Test Range (TTR) and an adjacent area of the Nevada Test and Training Range (NTTR) (formerly the Nellis Air Force Range). This operation resulted in radionuclide-contaminated soils at the Double Tracks site and Clean Slate I, II, and III sites. This report documents observations made during ongoing monitoring of radiological, meteorological, and dust conditions at stations installed adjacent to the Clean Slate sites and at the TTR Sandia National Laboratories (SNL) Range Operations Center (ROC). The primary objective of the monitoring effort is to support the DOE Environmental Management Nevada Program (EM NV) in the safe remediation of the environmental legacy of nuclear device development and testing by determining if wind blowing across the Clean Slate sites is transporting particles of radionuclide-contaminated soil beyond the physical and administrative boundaries of the sites, and to provide information for designing long-term monitoring of the sites. The monitoring program in 2018 included five stations. Station 400, located within TTR Area 3 and near the ROC, monitors conditions near the local workforce center. Stations 401 and 403 are located on the northern and southeastern perimeter fence lines, respectively, of the Clean Slate III site. Stations 404 and 405 are along the northern and eastern boundary fence, respectively, at Clean Slate II. The stations are generally downwind of the contaminated areas during either northwesterly or southerly winds, which are the predominant wind directions. The stations—which are similar in design to the Community Environmental Monitoring Program (CEMP) stations operating at locations surrounding the Nevada National Security Site and TTR—include meteorological instruments and continuous-flow, low-volume air samplers. Three pressurized ionization chambers for measuring gamma energy are in use at Stations 400, 401, and 403. Saltation sensors and saltation traps are deployed at the stations adjacent to the Clean Slate sites. Detailed meteorological data are recorded on data loggers, with periodic uploads via a satellite system to the Western Regional Climate Center (WRCC) at Desert Research Institute (DRI), to monitor instrument and site conditions. Air filter samples are collected every two weeks and the deposits in the saltation traps are collected when a sufficient sample mass for analysis has accumulated (generally a six- to eight-month interval). Monitoring at TTR in calendar year (CY) 2018 provided surveillance of both ambient conditions, and ground disturbance associated with remediation activities at Clean Slate II and III. The first half of CY2018 data from Stations 404 and 405 at Clean Slate II were collected during remediation activities at that site, and data collected during the final third of the year at Stations 401 and 403 at Clean Slate III coincided with remediation work at the site. Ambient conditions prevailed at Station 400 throughout the year. Dust transport by suspension and saltation is strongly dependent on wind speed. Concentrations of PM 10 (particulate matter of aerodynamic diameter ≤10 micrometers [μm], a size fraction of small particles that are suspended in the air and can be easily inhaled) remain low until winds exceed approximately 32 kilometers per hour (km/hr) (20 miles per hour [mph]). Saltation particle counts also increase above the same general threshold wind speed. Wind speeds in excess of 32 km/hr (20 mph) occur less than three percent of the time at the sites. Ground disturbing remediation activities were carried out at Clean Slate II from October 31, 2017, until July 26, 2018. Station 404 is located closest to the remediation area and is downwind of the area when winds are from the south. By late November, analysis of dust from the air sampler at Station 404 registered increases in plutonium-239+240 ( 239+240 Pu) concentrations. Peak plutonium concentrations, accompanied by elevated gross alpha concentrations and the detection of americium-241 ( 241 Am) by gamma spectroscopy, occurred between March and May 2018. During spring and early summer of 2018, elevated radionuclide concentrations were also measured in dust collected from the air sampler at Station 405, which is more than twice the distance from the remediation activity as Station 404. A minor but sustained increase in gross alpha concentration of suspended dust collected at Stations 400, 401, and 403 was also observed starting in May 2018 and continuing into August. Stations 401 and 403 are approximately 4.8 to 6.4 km (three to four miles) from Clean Slate II and Station 400 is approximately 13 km (eight miles) from that site. The radionuclide content of material that saltated into the passive Big Spring Number Eight (BSNE) traps during the Clean Slate II remediation period increased in both the traps facing toward and away from the fenced contamination area at Station 404, with the largest increases in concentration (almost five times the previous 239+240 Pu concentration) observed in the traps facing the fenced area. The radionuclide concentration in material in the trap facing away from the fence more than doubled from that measured in 2017. A similar increase was observed for the saltation trap facing away from the fenced area at Station 405, although no increase was observed for material captured in the trap facing the fenced area. Particles ranging in size from 50 to 500 µm generally move by saltation processes and are not expected to significantly contribute to dose for someone breathing in the standard respiratory zone for adult humans (1.5 to 1.7 m [4.9 to 5.6 ft] above ground level) because they are too large to be entrained in the air as suspended dust. Remediation activities at Clean Slate III began on September 5, 2018, and continued until a brief hiatus started on December 20, 2018. Although Station 401 is much closer to the remediation area than Station 403, the first increase in gross alpha and 239+240 Pu concentrations was noted in dust from filters collected at Station 403 in early November 2018. The highest radionuclide concentrations of 2018 at the Clean Slate III stations were recorded in air samples taken from Stations 401 and 403 in late December 2018 and these concentrations were comparable between the two station locations. Gamma rate data measured by the PICs was slightly higher than the annual average at Stations 401 and 403 after remediation activities began, but no single measurement was outside of the range observed in 2018 prior to remediation activities. No increase in radionuclide concentration was observed for the Clean Slate III remediation time period on air filters collected from the other stations. Radiological monitoring at Station 400—which is located at the ROC, and therefore the closest regularly staffed work location to the Clean Slate sites—recorded a higher mean gross alpha activity from dust collected on air sampler filters than in previous years. The individual biweekly air filters yielded measurements of gross alpha that were at or below the mean plus one standard deviation measured in CY2017, except for the period from April 25, 2018, through September 12, 2018. Nonetheless, gamma spectroscopy of all air filters from Station 400 identified only naturally occurring radionuclides, with no detection of americium-241 ( 241 Am) (which is used as an indicator of plutonium-241[ 241 Pu]). Alpha spectroscopy of selected air filters collected at Station 400 did not detect plutonium-238 ( 238 Pu) or 239+240 Pu above the analytical detection limit. Gross beta and gamma exposure rate data were comparable to data from regional CEMP stations. No saltation traps are deployed at Station 400. Considering the ambient monitoring periods during CY2018, the monitoring stations adjacent to the Clean Slate sites recorded above-background 238 Pu and 239+240 Pu concentrations (SNL, 1998; Turner et al., 2003) in samples collected by passive saltation traps and on selected air filters. These observations were consistent with previous years and indicated that radionuclide movement occurred under ambient conditions by processes of both saltation and suspension. The presence of radionuclides in all saltation traps, both upwind and downwind of the fenced contamination areas, was consistent with previous radiological survey results (EG&G, 1979) that show lower concentration radiologically contaminated material dispersed outside the fenced area. Although 239+240 Pu concentrations in the air filter samples were sometimes orders of magnitude higher than background, the concentrations were below risk-based action levels defined for an industrial area worker scenario (U.S. DOE, 2014). The interception of airborne dust with above-background radionuclide concentrations demonstrates that dispersal processes are continuing. Strong winds are the driver for both suspension and saltation of dust and soil. The recorded wind speed and PM10 during remediation activities at Clean Slate II and III identified discrete wind events lasting approximately five to eight hours each, which accounted for the greatest PM 10 concentrations at the monitoring stations. These events captured the effect of winds from the northwest and from the south. The observed differences in dust loading and radionuclide concentrations for the monitoring stations when they were either upwind or downwind of the contamination area identify the remediation area as a source of plutonium contaminated dust. The increase in concentration of radionuclides in airborne dust during the remediation activities, compared with measurements under previous ambient conditions (mean 239+240 Pu concentrations during remediation activities are approximately nine to 40 times higher compared to pre-remediation concentrations, depending on monitoring station), highlights the impact of land disturbance on wind-borne contaminant transport from the Clean Slate test areas. The meteorological and particulate matter monitoring indicated that conditions for wind-borne contaminant movement exist at the Clean Slate sites, and that transport of radionuclide-contaminated soil by both suspension and saltation occurred under ambient conditions and accelerated when the sites were disturbed. The 239+240 Pu alpha spectroscopy results indicated that airborne concentrations during remediation activities ranged from 2 × 10-16 to 380 × 10-16 µCi/ml. These results can be compared to the derived air concentration limit for 239 Pu of 6 × 10-11 µCi/ml for occupational workers contained in Code of Federal Regulations 10 CFR 835, Occupational Radiation Protection. Even though the air sampling results document an increase in concentration during remediation activities, the observed concentrations are less than 0.06 percent of the occupational limit. The Corrective Action Unit (CAU) closure strategy uses a risk-based approach, whereby acceptable contaminant concentrations are determined as a function of anticipated human exposure.

54 ENVIRONMENTAL SCIENCES↗

DOE OSTI2019

Performance and Compliance Monitoring - Different Objectives and Different Interpretation - 19109

Environmental surveillance and monitoring are a critical part of an overall strategy for protection of the public and environment. For site closure and disposal activities, monitoring and surveillance can be expected to continue many years into the future. In the case of environmental monitoring, two general types are commonly discussed: compliance and performance (or functional) monitoring. The objective of compliance monitoring is relatively clear. Compliance monitoring is conducted to demonstrate compliance with specific regulatory limits (e.g., maximum contaminant levels in groundwater). In this case, if your measurement is above these values, it is a regulatory concern. Monitoring can be especially challenging for engineered solutions involving robust barriers expected to last for decades or potentially hundreds or thousands of years. Although some gradual releases are expected to occur as barriers lose effectiveness, observable changes in groundwater are likely to be very small and may be delayed for very long times. For robust engineered systems, compliance in the near future is not expected to be a significant concern. The question becomes, what type of monitoring can be used to identify the potential for a compliance problem in the future? This has led to increasing use of performance monitoring as an early warning system. Rather than comparing against environmental standards, performance monitoring is compared against assumptions and results from a performance assessment. Performance monitoring is used to observe other potential indicators of changes in system behavior (vadose zone concentrations, changes in chemistry near the waste, changes in engineered features). Translating a change in a local measurement to a potential change in the concentration in an aquifer that would lead to a potential compliance concern in the future is a significant challenge for performance monitoring. Such monitoring needs to be more carefully interpreted and communicated than compliance monitoring. Considerations for implementation of performance monitoring are the focus of this paper. (authors)

12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗

DOE OSTI2015

SECARB Annual Report on In-Situ Monitoring Program

The Southeast Carbon Sequestration Partnership Phase III Anthropogenic Test at Citronelle Field is the United States’ largest prototype of commercial CO 2 capture from a coal-fired power station and transportation, injection, storage and monitoring. This report details the results of the second and third year of injection monitoring results for the Anthropogenic Test. Monitoring methods include both direct and indirect measurements. The Class V Experimental Permit requires extensive monitoring of injected CO 2 at the surface and at deep and shallow depths. The safety, integrity and information objectives of the CO 2 monitoring plan are in place to: (1) create and sustain wellbore integrity; (2) assure safe CO 2 injection operations; 3) verify the location and migration of the injected CO 2 plume; and (4) monitor for any CO 2 leakage. A robust suite of monitoring approaches are utilized for the insitu monitoring and include, pressure monitoring, various seismic surveys, pulsed neutron logging, reservoir fluid sampling and injection surveys. Data and observations collected using these monitoring methods will be used in the numerical model to inform the post-injection site care monitoring plan. This report describes actions pertaining to in situ monitoring at the Anthropogenic Test Site that were undertaken during the period of October 2013 to January 2015. This report details the results of the second and third year of injection monitoring results for the Anthropogenic Test. Work Product 9.2.2.b details the shallow monitoring results for 2014. CO 2 injection operations began on August 20, 2012 and terminated on September 1st 2014.

01 COAL, LIGNITE, AND PEAT↗

DOE OSTI2017

SECARB Report on Post-Injection In-Situ Monitoring

The Southeast Carbon Sequestration Partnership Phase III Anthropogenic Test at Citronelle Field is the United States’ largest prototype of commercial CO 2 capture from a coal-fired power station and transportation, injection, storage and monitoring. This report focuses on the results of the post-injection monitoring period for the Anthropogenic Test. Monitoring methods include both direct and indirect measurements. The Class V Experimental Permit requires extensive monitoring of injected CO 2 at the surface and at deep and shallow depths. The safety, integrity and information objectives of the CO 2 monitoring plan are in place to: (1) create and sustain wellbore integrity; (2) assure safe CO 2 injection operations; (3) verify the location and migration of the injected CO 2 plume; and (4) monitor for any CO 2 leakage. A robust suite of monitoring approaches is utilized for the in-situ monitoring and include, pressure monitoring, various seismic surveys, pulsed neutron logging, reservoir fluid sampling and injection surveys. Data and observations collected using these monitoring methods will be used in the numerical model to inform the post-injection site care monitoring plan. This report describes actions pertaining to in situ monitoring at the Anthropogenic Test Site that were undertaken during the period of September 2014 to May 2016. These monitoring techniques include the acquisition of pressure data, seismic data, pulsed neutron capture logs, reservoir fluid sampling, and tracer gas monitoring. CO 2 injection operations began on August 20, 2012 and terminated on September 1, 2014.

01 COAL, LIGNITE, AND PEAT↗

NASA NTRS2024

Wilson Corners, Solid Waste Management Unit 001(SWMU 01) 2023 Annual Long-Term Monitoring Report

This report presents a summary of the long-term monitoring (LTM) activities that occurred in 2023 at Wilson Corners, Solid Waste Management Unit 001, at Kennedy Space Center (KSC), Florida. Annual LTM of groundwater is being conducted at the site. Based on results from groundwater sampling activities performed during the 2019 through 2020 LTM reporting period and the 2020 and 2021 DPT groundwater sampling, it was determined that the LTM sampling plan was no longer meeting the goal of LTM because delineation was not verified and the installation of an air sparge (AS) system to treat the area of the High Concentration Plume was recommended. The AS System was installed in late 2022 and early 2023. System start-up activities were initiated in April 2023. Following system startup, several site wells required retrofitting to equip wellheads for withstanding the air pressure released from air sparge wells during system operation. Some site wells also required repair or abandonment, and replacement. Survey of location and top-of-casing of newly installed monitoring wells was combined with scheduled AS system survey activities and was completed in January 2024. The activities presented in this report include the February and April 2023 LTM monitoring well installations; March and April 2023 LTM and performance monitoring well water level gauging and sampling; November 2023 LTM well retrofits and repairs; a summary of December 2023 LTM well abandonments and installations (complete site well abandonment activities will be presented under a separate cover); and January 2024 LTM well survey. During the March and April 2023 sampling events, the low-flow sampling method was used, and samples were analyzed for a select list of volatile organic compounds. In March 2023, groundwater flow for the site was generally to the west was generally consistent with historical observations at the site. The Low Concentration Plume (LCP) continues to extend both horizontally and vertically beyond the terminal depth of the current monitoring well network. Data, inclusive of the 2023 LTM and baseline performance monitoring sampling events, indicate that the LCP encompasses an estimated 19.5 acres, compared to the 2021 LCP footprint, inclusive of the 2020 and 2021 DPT sampling events of 20.7 acres. The vertical extent of VOCs was historically delineated by monitoring wells screened greater than 48 feet below land surface (bls). The results from the three vertical extent monitoring wells screened below 48 feet bls that were sampled during the 2023 LTM indicate that groundwater vinyl chloride concentrations in these three wells are greater than the GCTL. As presented in the 2021 Long-Term Monitoring Report (NASA 2022), the KSCRT agreed to delay deeper investigations in this area to prevent the creation of additional pathways for vertical migration. Based on groundwater sampling activities performed in 2023, recommendations are to perform the next annual LTM sampling event, scheduled for April 2024 and to conduct quarterly performance monitoring of the AS System. The current selection of monitoring wells in the recommended 2024 LTM plan will provide an adequate data set for monitoring groundwater plume behavior; however, the LTM monitoring well network will be evaluated and refined based on 2024 LTM and year one performance monitoring data.

King Linnea↗

DOE OSTI2016

The history and outlook for seismic monitoring of nuclear explosions in the context of the Comprehensive Nuclear-Test-Ban Treaty

Modern methods of nuclear-explosion monitoring are vastly more capable than they were when underground nuclear testing began in the late 1950s, in part because a cycle of improvements in explosion monitoring in the 1960–80 period led to improvements in monitoring for earthquakes and other phenomena, which then led to a general growth in monitoring assets that in turn has been applied back to explosion monitoring. Practical experiences in nuclear-explosion monitoring, acquired during the era of active testing prior to finalization of the CTBT text in 1996, laid the basis for monitoring in support of this arms-control initiative. This article elaborates on the future of nuclear-test-monitoring technology, which can build upon an additional and remarkable growth of general monitoring assets that began in the 1990s, largely unrelated to the specifics of nuclear-test monitoring. A new cycle of improvements in earthquake monitoring is likely to improve monitoring for explosions. While it is not easy to quantify the degree of monitoring improvement afforded by such new assets, an example from North Korea indicates the improvement can be substantial.

99 GENERAL AND MISCELLANEOUS↗

DOE OSTI2018

Tonopah Test Range Air Monitoring: CY2017 Meteorological, Radiological, and Wind Transported Particulate Observations

In 1963, the U.S. Department of Energy (DOE) (formerly the Atomic Energy Commission [AEC]), implemented Operation Roller Coaster on the Tonopah Test Range (TTR) and an adjacent area of the Nevada Test and Training Range (NTTR) (formerly the Nellis Air Force Range). This operation resulted in radionuclide-contaminated soils at the Double Tracks site and Clean Slate I, II, and III sites. This report documents observations made during ongoing monitoring of radiological, meteorological, and dust conditions at stations installed adjacent to the Clean Slate sites and at the TTR Sandia National Laboratories (SNL) Range Operations Center (ROC). The primary objective of the monitoring effort is to support the DOE Environmental Management Nevada Program (EM NV) in the safe cleanup of the environmental legacy of nuclear device development and testing by determining if wind blowing across the Clean Slate sites is transporting particles of radionuclide-contaminated soil beyond the physical and administrative boundaries of the sites. The monitoring program underwent a significant change during 2017 with the decommissioning of one monitoring station and the establishment of three new stations. Station 400, located within TTR Area 3 and near the ROC, monitors conditions near the local workforce center and was in operation the full calendar year. Stations 401 and 403 are located on the northwest and southeast perimeter fence lines, respectively, of the Clean Slate III site. Station 401 operated throughout 2017, whereas Station 403 began operation at the end of April 2017. Stations 404 and 405 are along the northern and eastern boundary fence, respectively, at Clean Slate II and both began data collection at the end of April 2017. Also at the end of April, the Clean Slate I monitoring site, Station 402, was decommissioned. The stations are located to be generally downwind of the contaminated areas during either north-northwesterly or south-southeasterly winds, which are the predominant wind directions. The stations—which are similar in design to the Community Environmental Monitoring Program (CEMP) stations operating at locations surrounding the Nevada National Security Site and TTR—include meteorological instruments and continuous-flow, low-volume air samplers. Three pressurized ionization chambers for measuring gamma energy are in use at Stations 400, 401, and 403 (formerly at 402). Saltation sensors and saltation traps are deployed at the stations adjacent to the Clean Slate sites. Detailed meteorological data are recorded on data loggers, with periodic uploads via a satellite system to the Western Regional Climate Center (WRCC) at Desert Research Institute (DRI), to monitor instrument and site conditions. Air filter samples are collected every two weeks and the deposits in the saltation traps are collected when a sufficient sample mass for analysis has accumulated (generally a six- to eight-month interval). Dust transport by suspension and saltation is strongly dependent on wind speed. Concentrations of PM10 (particulate matter of aerodynamic diameter ≤10 micrometers [μm], a size fraction of small particles that are suspended in the air and can be easily inhaled) remain low until winds exceed approximately 32 km/hr (20 mph). Saltation particle counts also increase above the same general threshold wind speed. Wind speeds in excess of 32 km/hr (20 mph) occur less than three percent of the time. High winds are associated with two predominant directions: north-northwest and south. In 2017, the very highest winds were from the north, but all winds above 40 km/hr (25 mph) were approximately evenly split between south and northwest directions. The low-volume air samplers collect total suspended dust, and saltating particles are captured by the passive saltation traps, both for radiological analysis. Radionuclide monitoring at the ROC in TTR Area 3 (Station 400) found natural background levels of gross alpha and gross beta radiation. Similar background levels were found on filter samples analyzed using gamma and alpha spectroscopy. The gamma exposure rate data from pressurized ionization chambers (PIC) are comparable to those from the regional CEMP stations. Plutonium concentrations above background values were measured during 2017 from soil samples collected in passive saltation traps and on select air filters from the monitoring stations adjacent to the Clean Slate sites. The background for soils in the region is assumed to be 0.014 pCi/g plutonium-239+240 ( 239+240 Pu) as measured by Turner et al. (2003), whereas the background concentration of suspended 239+240Pu is assumed to be 9.5 x 10 -19 μCi/ml, which was determined by continuous air monitoring at the TTR airport in 1996 and 1997 (SNL, 1998). Background concentrations are exceeded by one to four orders of magnitude by the majority of samples from Clean Slate I, II, and III. The gross alpha and gross beta measurements of the air filters are also generally higher than those measured at the regional CEMP stations, although the gamma exposure rates determined by the PICs located at Clean Slate I and III are similar to CEMP measurements. The highest radionuclide concentrations of suspended dust are associated with individual filter samples from Clean Slate II Station 404 and Clean Slate III Station 401. Both of the stations are downwind of their respective sites during southerly winds, but they are also geographically closer to the highly contaminated detonation areas than the other monitoring stations. Considering all the analyzed samples, the 239+240Pu concentrations are generally higher for the Clean Slate II samples compared with those from Clean Slate III. The highest gross alpha and gross beta results are also observed for the Clean Slate II stations. The highest radionuclide concentrations are measured on the smaller (≤63 μm) saltation-sized particles and particulate matter collected downwind of each site. Nonetheless, traps oriented to collect dust moving toward the contamination areas also had plutonium concentrations significantly above background values, which is consistent with observations of low-level contamination dispersed beyond the fenced area. All the observed 239+240 Pu concentrations are below the risk-based action level (25 millirem per year, equivalent to a 239+240 Pu concentration of 4,120 pCi/g for an industrial worker scenario; U.S. DOE, 2014). The meteorological and particulate matter monitoring indicate that conditions for wind-borne contaminant movement exist at the Clean Slate sites, and that transport of radionuclide-contaminated soil by both suspension and saltation is occurring. The Corrective Action Unit (CAU) closure strategy uses a risk-based approach, whereby acceptable contaminant concentrations are determined as a function of anticipated human exposure. This strategy is consistent with the fence lines at the Clean Slate sites encircling areas of higher concentration and the observed presence of lower concentrations of contamination outside the fences.

54 ENVIRONMENTAL SCIENCES↗

DOE OSTI2024

Monitoring Plan for the Idaho National Laboratory Remote Handled Low Level Waste Disposal Facility

This monitoring plan for Idaho National Laboratory’s Remote-Handled Low Level Waste Disposal Facility was developed to meet the requirements for monitoring low-level waste disposal facilities according to the U.S. Department of Energy (DOE) Order 435.1, “Radioactive Waste Management,” and the guidance provided in the associated technical standard “Disposal Authorization Statement and Tank Closure Documentation” (DOE-STD-5002-2017). The purpose of this monitoring plan is to document a monitoring strategy that includes (1) compliance monitoring activities to demonstrate compliance with regulatory standards/limits and (2) performance monitoring to build confidence the facility is performing as demonstrated in the facility performance assessment (PA) (DOE-ID 2018a), composite analysis (CA) (DOE ID 2012), and CA addendum (DOE-ID 2018b). The de minimus impact to the aquifer predicted by the PA suggests that aquifer compliance monitoring should be augmented with performance monitoring of the drainage course materials and sedimentary interbeds in the vadose zone beneath the facility to provide a more effective means of identifying performance deviations. The monitoring approach delineated in this document was informed by the systems evaluation of natural and engineered facility features presented in the PA, an assessment of aquifer baseline conditions (INL 2017d), the dose analysis conducted in support of the PA and CA, and monitoring data collected during the first four years of facility operations (baseline monitoring phase) (INL 2023b). This plan provides monitoring locations, sampling frequencies, and sampling methods; recommendations for data evaluation; and a description of the monitoring plan implementation. Collected data will be used to demonstrate facility compliance and to identify conditions that are not consistent with the key assumptions made by the PA and CA.

12 - MGMT OF RADIOACTIVE AND NON-RADIOACTIVE WASTE↗

DOE OSTI2015

Handbook: Collecting Groundwater Samples from Monitoring Wells in Frenchman Flat, CAU 98

Frenchman Flat basin on the Nevada National Security Site (NNSS) contains Corrective Action Unit (CAU) 98, which is comprised of ten underground nuclear test locations. Environmental management of these test locations is part of the Underground Test Area (UGTA) Activity conducted by the U.S. Department of Energy (DOE) under the Federal Facility Agreement and Consent Order (FFACO) (1996, as amended) with the U.S. Department of Defense (DOD) and the State of Nevada. A Corrective Action Decision Document (CADD)/Corrective Action Plan (CAP) has been approved for CAU 98 (DOE, 2011). The CADD/CAP reports on the Corrective Action Investigation that was conducted for the CAU, which included characterization and modeling. It also presents the recommended corrective actions to address the objective of protecting human health and the environment. The recommended corrective action alternative is “Closure in Place with Modeling, Monitoring, and Institutional Controls.” The role of monitoring is to verify that Contaminants of Concern (COCs) have not exceeded the Safe Drinking Water Act (SDWA) limits (Code of Federal Regulations, 2014) at the regulatory boundary, to ensure that institutional controls are adequate, and to monitor for changed conditions that could affect the closure conditions. The long-term closure monitoring program will be planned and implemented as part of the Closure Report stage after activities specified in the CADD/CAP are complete. Groundwater at the NNSS has been monitored for decades through a variety of programs. Current activities were recently consolidated in an NNSS Integrated Sampling Plan (DOE, 2014). Although monitoring directed by the plan is not intended to meet the FFACO long-term monitoring requirements for a CAU (which will be defined in the Closure Report), the objective to ensure public health protection is similar. It is expected that data collected in accordance with the plan will support the transition to long-term monitoring at each CAU. The sampling plan is designed to ensure that monitoring activities occur in compliance with the UGTA Quality Assurance Plan (DOE, 2012). The sampling plan should be referenced for Quality Assurance (QA) elements and procedures governing sampling activities. The NNSS Integrated Sampling Plan specifies the groundwater monitoring that will occur in CAU 98 until the long-term monitoring program is approved in the Closure Report. The plan specifies the wells that must be monitored and categorizes them by their sampling objective with the associated analytical requirements and frequency. Possible sample collection methods and required standard operating procedures are also presented. The intent of this handbook is to augment the NNSS Integrated Sampling Plan by providing well-specific details for the sampling professional implementing the Sampling Plan in CAU 98, Frenchman Flat. This handbook includes each CAU 98 well designated for sampling in the NNSS Integrated Sampling Plan. The following information is provided in the individual well sections: 1. The purpose of sampling. 2. A physical description of the well. 3. The chemical characteristics of the formation water. 4. Recommended protocols for purging and sampling. The well-specific information has been gathered from numerous historical and current sources cited in each section, but two particularly valuable resources merit special mention. These are the USGS NNSS website (http://nevada.usgs.gov/doe_nv/ntsarea5.cfm) and the UGTA Field Operations website (https://ugta.nv.doe.gov/sites/Field%20Operations/default.aspx). 2 Land surface elevation and measuring point for water level measurements in Frenchman Flat were a focus during CAU investigations (see Appendix B, Attachment 1 in Navarro-Intera, 2014). Both websites listed above provide information on the accepted datum for each well. A summary is found on the home page for the well on the USGS website. Additional information is available through a link in the “Available Data” section to an “MP diagram” with a photo annotated with the datum information. On the UGTA Field Operations well page, the same information is in the “Wellhead Diagram” link. Well RNM-2s does not have an annotated photo at this time. All of the CAU 98 monitoring wells are located within Area 5 of Frenchman Flat, with the exception of ER-11-2 in Area 11 (Figure 1). The wells are clustered in two areas: the northern area (Figure 2) and the central area (Figure 3). Each well is discussed below in geographic order from north to south as follows: ER-11-2, ER-5-3 shallow piezometer, ER-5-3-2, ER-5-5, RNM-1, RNM-2s, and UE-5n.

(1996↗

NASA NTRS1996

GPS Monitor Station Upgrade Program at the Naval Research Laboratory

One of the measurements made by the Global Positioning System (GPS) monitor stations is to measure the continuous pseudo-range of all the passing GPS satellites. The pseudo-range contains GPS and monitor station clock errors as well as GPS satellite navigation errors. Currently the time at the GPS monitor station is obtained from the GPS constellation and has an inherent inaccuracy as a result. Improved timing accuracy at the GPS monitoring stations will improve GPS performance. The US Naval Research Laboratory (NRL) is developing hardware and software for the GPS monitor station upgrade program to improve the monitor station clock accuracy. This upgrade will allow a method independent of the GPS satellite constellation of measuring and correcting monitor station time to US Naval Observatory (USNO) time. THe hardware consists of a high performance atomic cesium frequency standard (CFS) and a computer which is used to ensemble the CFS with the two CFS's currently located at the monitor station by use of a dual-mixer system. The dual-mixer system achieves phase measurements between the high-performance CFS and the existing monitor station CFS's to within 400 femtoseconds. Time transfer between USNO and a given monitor station is achieved via a two way satellite time transfer modem. The computer at the monitor station disciplines the CFS based on a comparison of one pulse per second sent from the master site at USNO. The monitor station computer is also used to perform housekeeping functions, as well as recording the health status of all three CFS's. This information is sent to the USNO through the time transfer modem. Laboratory time synchronization results in the sub nanosecond range have been observed and the ability to maintain the monitor station CFS frequency to within 3.0 x 10 (sup minus 14) of the master site at USNO.

Galysh, Ivan J.↗

DOE OSTI2014

Multileaf collimator performance monitoring and improvement using semiautomated quality control testing and statistical process control

Purpose: High-quality radiation therapy using highly conformal dose distributions and image-guided techniques requires optimum machine delivery performance. In this work, a monitoring system for multileaf collimator (MLC) performance, integrating semiautomated MLC quality control (QC) tests and statistical process control tools, was developed. The MLC performance monitoring system was used for almost a year on two commercially available MLC models. Control charts were used to establish MLC performance and assess test frequency required to achieve a given level of performance. MLC-related interlocks and servicing events were recorded during the monitoring period and were investigated as indicators of MLC performance variations. Methods: The QC test developed as part of the MLC performance monitoring system uses 2D megavoltage images (acquired using an electronic portal imaging device) of 23 fields to determine the location of the leaves with respect to the radiation isocenter. The precision of the MLC performance monitoring QC test and the MLC itself was assessed by detecting the MLC leaf positions on 127 megavoltage images of a static field. After initial calibration, the MLC performance monitoring QC test was performed 3–4 times/week over a period of 10–11 months to monitor positional accuracy of individual leaves for two different MLC models. Analysis of test results was performed using individuals control charts per leaf with control limits computed based on the measurements as well as two sets of specifications of ±0.5 and ±1 mm. Out-of-specification and out-of-control leaves were automatically flagged by the monitoring system and reviewed monthly by physicists. MLC-related interlocks reported by the linear accelerator and servicing events were recorded to help identify potential causes of nonrandom MLC leaf positioning variations. Results: The precision of the MLC performance monitoring QC test and the MLC itself was within ±0.22 mm for most MLC leaves and the majority of the apparent leaf motion was attributed to beam spot displacements between irradiations. The MLC QC test was performed 193 and 162 times over the monitoring period for the studied units and recalibration had to be repeated up to three times on one of these units. For both units, rate of MLC interlocks was moderately associated with MLC servicing events. The strongest association with the MLC performance was observed between the MLC servicing events and the total number of out-of-control leaves. The average elapsed time for which the number of out-of-specification or out-of-control leaves was within a given performance threshold was computed and used to assess adequacy of MLC test frequency. Conclusions: A MLC performance monitoring system has been developed and implemented to acquire high-quality QC data at high frequency. This is enabled by the relatively short acquisition time for the images and automatic image analysis. The monitoring system was also used to record and track the rate of MLC-related interlocks and servicing events. MLC performances for two commercially available MLC models have been assessed and the results support monthly test frequency for widely accepted ±1 mm specifications. Higher QC test frequency is however required to maintain tighter specification and in-control behavior.

07 ISOTOPE AND RADIATION SOURCES↗

DOE OSTI2015

Ecological Monitoring and Compliance Program 2014 Report

The Ecological Monitoring and Compliance Program (EMAC), funded through the U.S. Department of Energy, National Nuclear Security Administration Nevada Field Office (NNSA/NFO, formerly Nevada Site Office), monitors the ecosystem of the Nevada National Security Site (NNSS) and ensures compliance with laws and regulations pertaining to NNSS biota. This report summarizes the program’s activities conducted by National Security Technologies, LLC (NSTec), during calendar year 2014. Program activities included (a) biological surveys at proposed activity sites, (b) desert tortoise compliance, (c) ecosystem monitoring, (d) sensitive plant species monitoring, (e) sensitive and protected/regulated animal monitoring, and (f) habitat restoration monitoring. During 2014, all applicable laws, regulations, and permit requirements were met, enabling EMAC to achieve its intended goals and objectives. Sensitive and protected/regulated species of the NNSS include 42 plants, 1 mollusk, 2 reptiles, 236 birds, and 27 mammals. These species are protected, regulated, or considered sensitive according to state or federal regulations and natural resource agencies and organizations. The desert tortoise (Gopherus agassizii) and the western yellow-billed cuckoo (Coccyzus americanus) are the only species on the NNSS protected under the Endangered Species Act, both listed as threatened. However, only one record of the cuckoo has ever been documented on the NNSS, and there is no good habitat for this species on the NNSS. It is considered a rare migrant. Biological surveys for the presence of sensitive and protected/regulated species and important biological resources on which they depend were conducted for 18 projects. A total of 199.18 hectares (ha) was surveyed for these projects. Sensitive and protected/regulated species and important biological resources found during these surveys included a predator burrow, one sidewinder rattlesnake (Crotalus cerastes), two mating speckled rattlesnakes (Crotalus mitchellii), and several species of cacti. NSTec provided to project managers a written summary report of all survey findings and mitigation recommendations, where applicable. Of the 18 projects on the NNSS, 15 occurred within the range of the threatened desert tortoise. Approximately 2.19 ha of desert tortoise habitat were disturbed. No desert tortoises were accidentally injured or killed by project activities, and no tortoises were killed by vehicles. On 13 occasions, tortoises were moved off the road and out of harm’s way. Six tortoises were found and transmitters attached as part of an approved study to assess impacts of vehicles on tortoises on the NNSS. NSTec biologists continued to monitor 37 juvenile desert tortoises as part of a collaborative effort to study survival and temperament of translocated animals. From 1978 until 2013, there has been an average of 11.2 wildland fires per year on the NNSS with an average of about 83.7 ha burned per fire. There were no wildland fires documented on the NNSS during 2014. Results from the wildland fuel surveys showed a very low risk of wildland fire due to reduced fuel loads caused by limited natural precipitation. Limited reptile trapping and reptile roadkill surveys were conducted to better define species distribution on the NNSS. Sixteen reptiles were trapped representing five species. Combined with data from 2013, 183 road kills were detected, representing 11 snake and 8 lizard species. Selected natural water sources were monitored to assess trends in physical and biological parameters, and one new water source was found. Wildlife use at five water troughs and four radiologically contaminated sumps was documented using motion-activated cameras. As part of the statewide effort to disseminate information throughout the botanical community, NSTec prepared a shape file with site-specific data for all 17 sensitive plants on the NNSS and provided it to the Nevada Natural Heritage Program for inclusion in their statewide database. No field surveys were conducted this year for sensitive plants on the NNSS due to poor growing conditions. Surveys of sensitive and protected/regulated animals during 2014 focused on winter raptors, bats, wild horses (Equus caballus), mule deer (Odocoileus hemionus), desert bighorn sheep (Ovis Canadensis nelsoni), and mountain lions (Puma concolor). Two permanent, long-term winter raptor survey routes were established and sampled in January and February. A total of 27 raptors representing 4 species were observed. The wild horse population increased from 30 to 41, with several yearlings recruiting into the population, possibly due to the death of a mountain lion known to prey on horse foals. Mule deer abundance and density measured with standardized deer surveys was similar to 2013 and appears to be stable. Desert bighorn sheep, including rams, ewes, and lambs, were detected using motion-activated cameras at four water sources. There are plans to conduct helicopter surveys to census the population during September 2015 and then capture and radio-collar up to 20 sheep during November 2015. Over 150 sheep scat samples have been collected for genetic analysis to try to determine how sheep on the NNSS are related to surrounding sheep populations. Information is presented about bird mortalities, Migratory Bird Treaty Act compliance, and a summary of nuisance animals and their control on the NNSS. A total of 93 mountain lion images (i.e., photographs or video clips) were taken during 220,379 camera hours at 16 of 32 sites sampled and another 11,946 images of at least 29 species other than mountain lions were taken as well. A mountain lion telemetry study continued in 2014. NNSS7 was tracked from January 1 to November 15 using a global positioning system satellite transmitter. He consumed 21 mule deer, 17 desert bighorn sheep, 1 juvenile bobcat, and 3 coyotes. Mule deer were primarily taken in the summer and fall. No new mountain lions were captured. A minimum of four adult lions (two males, two females), a subadult male, and three kittens were known to inhabit the NNSS during 2014. Two previously revegetated sites on the NNSS and one on the Tonopah Test Range (TTR) were monitored in 2014. The cover cap on the U-3ax/bl disposal unit, revegetated in 2000, and the 92-Acre Site at the Area 5 Radioactive Waste Management Complex, revegetated in 2011, were the restoration sites monitored on the NNSS. The Corrective Action Unit 407 Rollercoaster RADSAFE site, revegetated in 2000, was the restoration site monitored on the TTR. Plant cover and density were recorded at all sites except U-3ax/bl (qualitative monitoring), and reclamation success standards were evaluated, where applicable.

54 ENVIRONMENTAL SCIENCES↗

DOE OSTI2018

Project 57 Air Monitoring Report: January 1 through December 31, 2017

On April 24, 1957, the Atomic Energy Commission (AEC) (now the Department of Energy [DOE]) conducted the Project 57 safety experiment in western Emigrant Valley northeast of the Nevada National Security Site (NNSS, formerly the Nevada Test Site) on lands withdrawn by the Department of Defense (DOD) for the Nevada Test and Training Range (NTTR). The test was undertaken to develop (1) a means of estimating plutonium distribution resulting from a non-nuclear detonation; (2) biomedical evaluation techniques for use in plutonium-laden environments; (3) methods of surface decontamination; and (4) instruments and field procedures for prompt estimation of alpha contamination (Shreve, 1958). Although the test did not result in the fission of nuclear materials, it did disseminate plutonium across the land surface. Following the experiment, the AEC fenced the contaminated area and returned control of the surrounding land to the DOD. Various radiological surveys were performed in the area and in 2007, the DOE expanded the demarked Contamination Area (CA) by posting signs 200 to 400 ft (60 to 120 m) outside of the original fence. Plutonium in soil attaches preferentially to smaller particles (Tamura, 1985; Friesen, 1992; Murarik et al., 1992; and Misra et al., 1993). Therefore, redistribution of soil particles by wind (dust) and water are the mechanisms most likely to transport plutonium beyond the boundary of the Project 57 CA. Monitoring was implemented in 2011 by Desert Research Institute (DRI) to determine if radionuclide contamination was detectable in samples of airborne dust and to characterize meteorological and environmental parameters that influence dust transport. Initially, two monitoring stations consisting of radiological, meteorological, and dust sampling equipment were installed near the southeast and northeast corners of the CA. In January 2015, the original monitoring stations were dismantled and moved farther to the west along the CA boundary. This move was made to place the monitoring stations downwind of ground zero and the High Contamination Area (HCA) during the dominant northerly and southerly winds. Samples of particles suspended in the air are collected every two weeks and submitted for laboratory assessments of gross alpha and gross beta radioactivity, and for determinations of gamma-emitting radionuclides. In calendar year (CY) 2017, the mean gross alpha concentration at monitoring station P57-4 was approximately 4.25 times the value at monitoring station P57-3. In CY2015 and CY2016, the difference in mean gross alpha concentration at the two stations was approximately 1.5. The mean gross alpha concentrations at P57-3 and P57-4 were approximately 1.9 and 7.9 times, respectively, the mean gross alpha concentrations at the surrounding Community Environmental Monitoring Program (CEMP) stations. The minimum gross alpha concentrations reported for the Project 57 stations are in the range of the minimum values observed at the CEMP stations. However, maximum gross alpha concentrations are greater than the maximum concentrations observed at the surrounding CEMP stations. Gamma spectroscopy analyses resulted in the detection of seven radionuclides. Except for americium-241 (Am-241), all reported radionuclides occur naturally in the environment. The Am-241 detection by gamma spectroscopy was confirmed by alpha spectroscopy. During each quarter of CY2017, four suspended particulate matter samples were selected for alpha spectroscopy analysis. Two were selected each quarter from the regular biweekly samples collected at each of the two monitoring stations. Of the eight samples from P57-3, one was reported to have plutonium-238 (Pu-238) above the minimum detectable activity (MDA) and five were reported to have plutonium 239/240 (Pu-239/240) above the MDA. Of the eight samples from P57-4, three were reported to have Pu-238 above the MDA and six were reported to have Pu-239/240 above the MDA. Soil material is also transported by saltation, which is a wind driven phenomena that bounces sand-sized soil particles across the land surface because they are too heavy to be suspended in the air. Samples of particles transported by saltation were collected downwind and upwind of the CA at both monitoring stations in May 2017 after a 190-day deployment and again in September 2017 after a 114-day deployment. Mass of the saltation samples was determined after oven drying. The September sample had greater mass than the May sample. The same relationship was observed for the suspended particulate matter samples during periods of saltation sample collection. The difference in the collected mass appears to be because of the amount of soil moisture. Higher soil moisture exerts additional isotopic bonds between soil particles and water molecules, and between water molecules that envelop soil particles, making it more difficult for wind to raise the particles as dust. In general, samples collected from saltation traps facing south contained more material than samples collected from traps facing north. This suggests that although saltation material may have been moving back and forth in conjunction with the two dominant wind directions, there was a net trend for saltation material to be transported toward the north. Radiological analyses of the saltation samples show that the smaller particle size faction (<63 μm) generally produced the highest activity levels of Am-241, Pu-238, and Pu-239/240. In general, the isotope activity levels decreased as the particle size increased. These results are consistent with the expectation that the greatest potential for transport of radiological contamination is with the smaller particles. Thermoluminescent dosimeters (TLDs) indicated that the average annual external radioactivity dose at the monitoring stations is slightly higher than the dose determined at the surrounding CEMP stations, but approximately half of the estimated national average dose received by the general public from exposure to natural sources. The TLDs at the Project 57 monitoring stations are exposed to both natural sources (terrestrial and cosmic) and radioactive releases from the Project 57 CA. Winds in excess of approximately 15 mph (24 km/hr) begin to generate dust movement by saltation or suspension, as determined by the monitoring instruments. Saltated particles, PM10 (i.e., inhalable dust), and PM2.5 (i.e., fine particulate dust) exhibit an approximately exponential increase with increasing wind speed. The greatest concentrations of dust occurred for winds exceeding 20 mph (32 km/hr). When the wind/dust analysis was performed for winds separated into the dominant northerly and southerly wind directions, it was evident that the northerly winds generated the higher PM10 concentrations and had the dominate influence on the PM10 concentration determined for all wind speeds when all wind directions were evaluated together. During the year, winds in excess of 20 mph (32 km/hr) occurred approximately one percent of the time. Although winds sufficient to generate dust occur at the Project 57 site, they are infrequent and of short duration. A preliminary assessment of individual wind events suggests that dust generation in response to specific wind conditions is highly variable. Wind speeds that would be expected to generate noticeable dust may not do so in every instance. Additionally, saltation transport in response to wind conditions was less common than expected. These variations were likely because of the influence of meteorological and environmental parameters other than wind.

54 ENVIRONMENTAL SCIENCES↗

DOE OSTI2018

Assessment of Multiple Monitoring Methods for Detection of Brine and CO2 Leakage

We assess the effectiveness of four surface-based geophysical methods and in situ monitoring of pressure and chemical changes for detecting brine and CO2 leakage from legacy wells into underground sources of drinking water (USDW) overlying a CO2 storage reservoir. This is the first such effort to evaluate and compare six monitoring methods for detection of CO2 leakage. This assessment, conducted in support of the USDOE National Risk Assessment Partnership (NRAP), utilizes 3000 synthetic data sets, generated in an uncertainty quantification (UQ) model framework. This framework combines the results of (1) a CO2 storage reservoir model of a hypothetical storage operation of 5 MT/yr for 50 years into the 1700-m deep Vedder Fm. at a site near Kimberlina, California with (2) wellbore leakage models of a legacy well and (3) multi-phase flow and reactive transport models of brine and CO2 plume migration in aquifer layers overlying the storage reservoir. Leakage drives subsurface changes, quantified by pressure plumes, CO2-saturation plumes, and total dissolved solids (TDS) plumes, the latter being related to changes in pH and species concentrations. Depending on the depth of leakage, aquifer permeability, and regional groundwater gradient, pressure plume volumes can become larger than the CO2 and TDS plumes; however, reaching detectable thresholds may take too long to be useful. For a single monitoring well located 500 m downgradient of a leaky legacy well, a depth of 570 m is found to be optimal for sampling pressure and chemical changes. We assess four surface-based geophysical monitoring methods: electrical resistivity tomography (ERT), magnetotellurics (MT), gravity, and seismic methods. Sensors cover a 4-km × 2-km area. Both ERT and MT methods are sensitive to changes in CO2 saturation and TDS concentration, whereas gravity and seismic methods detect changes in CO2 saturation. The six monitoring methods complement each other in space and time, and we find that a minimum of 20 kT of CO2 leakage is required for the leakage plume to be detected. Of the four surface-based geophysical methods, gravity monitoring appears to be the most sensitive to CO2 leaks, while the usefulness of in situ pressure and chemical monitoring will depend on the level of unfilterable background noise. Geophysical monitoring methods may detect a leak anywhere in a large area and in a large depth range, but the effectiveness of pressure and chemical monitoring depends on the number of monitoring wells, where those wells are located, and the depth of sampling. Surface-based geophysical monitoring methods are cost-effective alternatives to in situ pressure and chemical monitoring methods.

NRAP, CCS, monitoring, geophysical methods, gravit↗

DOE OSTI2016

Refining Groundwater Monitoring Approaches Through an Objectives-Driven Process - 16333

Groundwater monitoring is conducted throughout the groundwater remediation process, from initial site characterization through demonstration of cleanup objectives attainment. The DOE uses the groundwater monitoring data to define plumes, manage ongoing remediation, and determine how close the contamination levels are to meeting an endpoint criteria, such as a drinking water standard. Due to the expense of groundwater sampling and analysis, the DOE Office of Environmental Management compiled a synopsis of monitoring technologies and approaches, and defined opportunities for improving environmental remediation monitoring. This information included techniques to optimize and streamline groundwater monitoring. At the Hanford Site, years of extensive groundwater monitoring have been applied to support characterization and remedy-selection activities. Continuation of this monitoring intensity would be costly and would need to be reviewed in the context of future activities for groundwater remedy implementation. A structured review of monitoring plans is underway and has identified significant potential changes to the monitoring approach. These changes have been developed based on careful definition of monitoring objectives and consideration of innovative and targeted techniques to gather the appropriate data for remedy performance monitoring and transition to longer-term monitoring and closure. (authors)

12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗

DOE OSTI2016

Silicon Carbide Temperature Monitor Processing Improvements. Status Report

Silicon carbide (SiC) temperature monitors are used as temperature sensors in Advanced Test Reactor (ATR) irradiations at the Idaho National Laboratory (INL). Although thermocouples are typically used to provide real-time temperature indication in instrumented lead tests, other indicators, such as melt wires, are also often included in such tests as an independent technique of detecting peak temperatures incurred during irradiation. In addition, less expensive static capsule tests, which have no leads attached for real-time data transmission, often rely on melt wires as a post-irradiation technique for peak temperature indication. Melt wires are limited in that they can only detect whether a single temperature is or is not exceeded. SiC monitors are advantageous because a single monitor can be used to detect for a range of temperatures that occurred during irradiation. As part of the process initiated to make SiC temperature monitors available at the ATR, post-irradiation evaluations of these monitors have been previously completed at the High Temperature Test Laboratory (HTTL). INL selected the resistance measurement approach for determining irradiation temperature from SiC temperature monitors because it is considered to be the most accurate measurement. The current process involves the repeated annealing of the SiC monitors at incrementally increasing temperature, with resistivity measurements made between annealing steps. The process is time consuming and requires the nearly constant attention of a trained staff member. In addition to the expensive and lengthy post analysis required, the current process adds many potential sources of error in the measurement, as the sensor must be repeatedly moved from furnace to test fixture. This time-consuming post irradiation analysis is a significant portion of the total cost of using these otherwise inexpensive sensors. An additional consideration of this research is that, if the SiC post processing can be automated, it could be performed in an MFC hot cell, further reducing the time and expense of lengthy decontaminations prior to processing. Sections of this report provide a general description of resistivity techniques currently used to infer peak irradiation temperature from silicon carbide temperature monitors along with some representative data, the proposed concepts to improve the process of analyzing irradiated SiC temperature monitors, the completed efforts to prove the proposed concepts, and future activities. The efforts detailed here succeeded in designing and developing a real-time automated SiC resistivity measurement system, and performed two initial test runs. Activities carried out include the assembly and integration of the system hardware; the design and development of a preliminary monitor fixture; the design of a technique to automate the data analysis and processing; the development of the communication, coordination, and user software; and the execution and troubleshooting of test run experiments using the box furnace. Although the automation system performed as required, the designed fixture did not succeed in establishing the needed electrical contacts with the SiC monitor.

46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND ↗

DOE OSTI2015

SU-E-T-258: Development of a New Patient Set-Up Monitoring System Using Force Sensing Resistor (FSR) Sensor for the Radiation Therapy

Purpose: The purpose of this work is to develop a new patient set-up monitoring system using force sensing resistor (FSR) sensors that can confirm pressure of contact surface and evaluate its feasibility. Methods: In this study, we focused on develop the patient set-up monitoring system to compensate for the limitation of existing optical based monitoring system, so the developed system can inform motion in the radiation therapy. The set-up monitoring system was designed consisting of sensor units (FSR sensor), signal conditioning devices (USB cable/interface electronics), a control PC, and a developed analysis software. The sensor unit was made by attaching FSR sensor and dispersing pressure sponge to prevent error which is caused by concentrating specific point. Measured signal from the FSR sensor was sampled to arduino mega 2560 microcontroller, transferred to control PC by using serial communication. The measured data went through normalization process. The normalized data was displayed through the developed graphic user interface (GUI) software. The software was designed to display a single sensor unit intensity (maximum 16 sensors) and display 2D pressure distribution (using 16 sensors) according to the purpose. Results: Changes of pressure value according to motion was confirmed by the developed set-up monitoring system. Very small movement such as little physical change in appearance can be confirmed using a single unit and using 2D pressure distribution. Also, the set-up monitoring system can observe in real time. Conclusion: In this study, we developed the new set-up monitoring system using FSR sensor. Especially, we expect that the new set-up monitoring system is suitable for motion monitoring of blind area that is hard to confirm existing optical system and compensate existing optical based monitoring system. As a further study, an integrated system will be constructed through correlation of existing optical monitoring system. This work was supported by the Industrial R&D program of MOTIE/KEIT. [10048997, Development of the core technology for integrated therapy devices based on real-time MRI guided tumor tracking] and the Mid-career Researcher Program (2014R1A2A1A10050270) through the National Research Foundation of Korea funded by the Ministry of Science, ICT&Future Planning.

60 APPLIED LIFE SCIENCES↗

DOE OSTI2016

Development of a CO 2 Chemical Sensor for Downhole CO 2 Monitoring in Carbon Sequestration

Geologic storage of carbon dioxide (CO 2 ) has been proposed as a viable means for reducing anthropogenic CO 2 emissions. The means for geological sequestration of CO 2 is injection of supercritical CO 2 underground, which requires the CO 2 to remain either supercritical, or in solution in the water/brine present in the underground formation. However, there are aspects of geologic sequestration that need further study, particularly in regards to safety. To date, none of the geologic sequestration locations have been tested for storage integrity under the changing stress conditions that apply to the sequestration of very large amounts of CO 2 . Establishing environmental safety and addressing public concerns require widespread monitoring of the process in the deep subsurface. In addition, studies of subsurface carbon sequestration such as flow simulations, models of underground reactions and transports require a comprehensive monitoring process to accurately characterize and understand the storage process. Real-time information about underground CO 2 movement and concentration change is highly helpful for: (1) better understanding the uncertainties present in CO 2 geologic storage; (2) improvement of simulation models; and (3) evaluation of the feasibility of geologic CO 2 storage. Current methods to monitor underground CO 2 storage include seismic, geoelectric, isotope and tracer methods, and fluid sampling analysis. However, these methods commonly resulted low resolution, high cost, and the inability to monitor continuously over the long time scales of the CO 2 storage process. A preferred way of monitoring in-situ underground CO 2 migration is to continuous measure CO 2 concentration change in brine during the carbon storage process. An approach to obtain the real time information on CO 2 concentration change in formation solution is highly demanded in carbon storage to understand the CO 2 migration subsurface and to answer the public safety problem. The objective of the study is to develop a downhole CO 2 sensor that can in-situ, continuously monitor CO 2 concentration change in deep saline. The sensor is a Severinghaus-type CO 2 sensor with small size, which renders it can be embedded in monitoring well casing or integrated with pressure/temperature transducers, enabling the development of “smart” wells. The studies included: (1) prepare and characterize metal-oxide electrodes. Test the electrodes response to pH change. Investigate different ions and brine concentration effects on the electrode’s performance. Study the stability of the electrode in brine solution; (2) fabricate a downhole CO 2 sensor with the metal-oxide electrodes prepared in the laboratory. Test the performance of the CO 2 sensor in brine solutions. Study high pressure effects on the performance of the sensor; (3) design and conduct CO 2 /brine coreflooding experiments with the CO2 sensor. Monitor CO 2 movement along the core and test the performance of the sensor in coreflooding tests. Develop a data acquisition system that can digitize the sensor’s output voltage. Our completed research has resulted in deep understanding of downhole CO 2 sensor development and CO 2 monitoring in CO 2 storage process. The developed downhole CO 2 sensor included a metal-oxide electrode, a gas-permeable membrane, a porous steel cup, and a bicarbonate-based internal electrolyte solution. Iridium oxide-based electrode was prepared and used for preparation the CO 2 sensor. The prepared iridium oxide-based electrode displayed a linearly response to pH change. Different factors such as different ions and ions concentration, temperature, and pressure effects on the electrode performance on pH response were investigated. The results indicated that the electrode exhibited a good performance even in high salt concentration of produced water. To improve the electrode performance under high pressure, IrO 2 nanoparticles with the particle size in the range of 1-2 nm were prepared and electrodeposited on stainless steel substrate by cyclic voltammetry. It was observed that the thin film of iridium oxide was formed on the substrate surface and such iridium oxide-based electrode displayed excellent performance under high pressure for longer term. A downhole CO 2 sensor with the iridium oxide-based electrode was prepared. The working principle of the CO 2 sensor is based on the measurement of the pH change of the internal electrolyte solution caused by the hydrolysis of CO 2 and then determination of the CO 2 concentration in water. The prepared downhole CO 2 sensor had the size of diameter of 0.7 in. and length of 1.5 in. The sensor was tested under the pressures of 500 psi, 2,000 psi, and 3,000 psi. A linear correlation was observed between the sensor potential change and dissolved CO 2 concentration in water. The response time of the CO 2 sensor was in the range of 60-100 minutes. Further tests indicated that the CO 2 sensor exhibited good reproducibility under high pressure. A CO 2 /brine coreflooding system was constructed to simulate the real-world CO 2 storage process. The prepared downhole CO 2 sensor was loaded in the system to monitor CO 2 movement during CO 2 /brine coreflooding test. The results indicated that the sensor could detect CO 2 movement in the tests. Further studies showed that the sensor could be recovered by brine flooding after CO 2 /brine flushed the core. The results of the coreflooding tests demonstrated that the sensor had potential application for CO 2 monitoring in carbon sequestration. A data acquisition system for the downhoe CO 2 sensor was developed and coded. The system converted the sensor output signal into digital data and transported the data from downhole to wellhead surface. The data acquisition system was tested and evaluated in the laboratory with the prepared sensor for data collection.

36 MATERIALS SCIENCE↗