22 research outputs found
Ultrasonic Examination of Double-Shell Tank 241-AY-101. Examination Completed March 2007.
AREVA NC Inc. (AREVA), under a contract from CH2M Hill Hanford Group (CH2M Hill), has performed an ultrasonic examination of selected portions of Double-Shell Tank 241-AY-101. PNNL is responsible for preparing a report(s) that describes the results of the AREVA ultrasonic examinations
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Ultrasonic Examination of Double-Shell Tank 241-AY-102. Examination Completed January 2007
AREVA NC Inc. (AREVA), under a contract from CH2M Hill Hanford Group (CH2M Hill), has performed an ultrasonic examination of selected portions of Double-Shell Tank 241-AY-102. PNNL is responsible for preparing a report(s) that describes the results of the AREVA ultrasonic examinations
Evaluation of UT Wall Thickness Measurements and Measurement Methodology
CH2M HILL has requested that PNNL examine the ultrasonic methodology utilized in the inspection of the Hanford double shell waste tanks. Specifically, PNNL is to evaluate the UT process variability and capability to detect changes in wall thickness and to document the UT operator's techniques and methodology in the determination of the reported minimum and average UT data and how it compares to the raw (unanalyzed) UT data
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Estimation of Maximum Wall Thickness Loss of Five DSTs (AN-107, AP-102, AW-101, AZ-102, and SY-101)
The DST Integrity Plan requires the ultrasonic wall thickness measurement of two vertical scans of the tank primary wall from a single riser. The resulting measurements are then used in an extreme value methodology to predict the minimum wall thickness expected for the entire tank. The methodology was developed in previous work by the authors of this report. A component of the methodology is to consider the possible impact of riser differences had multiple risers instead been used. The approach is based on previous analyses of Tank AY-101 which had measurements taken from multiple risers. This report presents estimated maximum wall thickness loss for five DST's with associated uncertainty estimation and confidence bounds. Several sources of variability are incorporated since the individual sources cannot be separated. These sources include original manufacturing plate thickness and the precision of the measurement process, as well as loss due to corrosion, the actual feature of interest
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Radiation Doses to Hanford Workers from Natural Potassium-40
The chemical element potassium is an essential mineral in people and is subject to homeostatic regulation. Natural potassium comprises three isotopes, 39K, 40K, and 41K. Potassium-40 is radioactive, with a half life of 1.248 billion years. In most transitions, it emits a β particle with a maximum energy of 0.560 MeV, and sometimes a gamma photon of 1.461 MeV. Because it is ubiquitous, 40K produces radiation dose to all human beings. This report contains the results of new measurements of 40K in 248 adult females and 2,037 adult males performed at the Department of Energy Hanford Site in 2006 and 2007. Potassium concentrations diminish with age, are generally lower in women than in men, and decrease with body mass index (BMI). The average annual effective dose from 40K in the body is 0.149 mSv y−1 for men and 0.123 mSv y−1 women respectively. Averaged over both men and women, the average effective dose per year is 0.136 mSv y−1. Calculated effective doses range from 0.069 to 0.243 mSv y−1 for adult males, and 0.067 to 0.203 mSv y−1 for adult females, a roughly three-fold variation for each gender. The need for dosimetric phantoms with a greater variety of BMI values should be investigated. From our data, it cannot be determined whether the potassium concentration in muscle in people with large BMI values differs from that in people with small BMI values. Similarly, it would be important to know the potassium concentration in other soft tissues, since much of the radiation dose is due to beta radiation, in which the source and target tissues are the same. These uncertainties should be evaluated to determine their consequences for dosimetry
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Ultrasonic Examination of Double-Shell Tank 241-AN-102 Examination Completed July 2008.
AREVA Federal Services LLC (AFS), under a contract from CH2M Hill Hanford Group (CH2M Hill), has performed an ultrasonic examination of selected portions of Double-Shell Tank 241-AN-102. PNNL is responsible for preparing a report(s) that describes the results of the AFS ultrasonic examinations
Ultrasonic Examination of Double-Shell Tank 241-AW-103. Examination Completed September 2006
AREVA NC Inc. (AREVA), under a contract from CH2M Hill Hanford Group (CH2M Hill), has performed an ultrasonic examination of selected portions of Double-Shell Tank 241-AW-103. PNNL is responsible for preparing a report(s) that describes the results of the AREVA ultrasonic examinations. The purpose of this examination was to provide information that could be used to evaluate the integrity of the wall of the primary and secondary tank. The requirements for the ultrasonic examination of Tank 241-AW-103 were to detect, characterize (identify, size, and locate), and record measurements made of any wall thinning, pitting, or cracks that might be present in the wall of the primary tank and the wall of the secondary tank. Any measurements that exceed the requirements set forth in the Engineering Task Plan (ETP), RPP-Plan-27202 (Jensen 2005) and summarized on page 1 of this document, are to be reported to CH2M Hill and the Pacific Northwest National Laboratory (PNNL) for further evaluation. Under the contract with CH2M Hill, all data is to be recorded on electronic media and paper copies of all measurements are provided to PNNL for third-party evaluation. PNNL is responsible for preparing a report(s) that describes the results of the AREVA ultrasonic examinations. The results of the examination of Tank 241-AW-103 have been evaluated by PNNL personnel. The primary tank ultrasonic examination consisted of two vertical 15-in.-wide scan paths over the entire height of the tank, the heat-affected zone (HAZ) of four vertical welds and one horizontal weld from Riser 29 and two vertical 15-in.-wide scan paths over the entire height of the tank from Riser 28. Additionally, two vertical 15-in.-wide scan paths over the entire height of the secondary tank from Riser 28 were performed. The examinations were performed to detect any wall thinning, pitting, or cracking in the primary tank wall
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Ultrasonic Examination of Double-Shell Tank 241-AP-107 Examination Completed February 2008
AREVA Federal Services LLC (AFS), under a contract from CH2M HILL Hanford Group (CH2M HILL), has performed an ultrasonic examination of selected portions of Double-Shell Tank 241-AP-107. The purpose of this examination was to provide information that could be used to evaluate the integrity of the wall of the primary tank. The requirements for the ultrasonic examination of Tank 241-AP-107 were to detect, characterize (identify, size, and locate), and record measurements made of any wall thinning, pitting, or cracks that might be present in the wall of the primary tank. Any measurements that exceed the requirements set forth in the Engineering Task Plan (ETP), RPP-Plan-34301 (Castleberry 2007) and summarized on page 1 of this document, are to be reported to CH2M HILL and the Pacific Northwest National Laboratory (PNNL) for further evaluation. Under the contract with CH2M HILL, all data is to be recorded on electronic media and paper copies of all measurements are provided to PNNL for third-party evaluation. PNNL is responsible for preparing a report(s) that describes the results of the AFS ultrasonic examinations
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Evaluation of Ultrasonic Measurement Variation in the Double-Shell Tank Integrity Project
Washington River Protection Solutions (WRPS) under contract from the U.S. Department of Energy (DOE) is responsible for assessing the condition of the double-shell tanks (DST) on the Hanford nuclear site. WRPS has contracted with AREVA Federal Services LLC (AFS) to perform ultrasonic testing (UT) inspections of the 28 DSTs to assess the condition of the tanks, judge the effects of past corrosion control practices, and satisfy a regulatory requirement to periodically assess the integrity of the tanks. Since measurement inception in 1997, nine waste tanks have been examined twice (at the time of this report) providing UT data that can now be compared over specific areas. During initial reviews of these two comparable data sets, average UT wall-thickness measurement reductions were noted in most of the tanks. This variation could be a result of actual wall thinning occurring on the waste-tanks walls, or some other unexplained anomaly resulting from measurement error due to causes such as the then-current measurement procedures, operator setup, or equipment differences. WRPS contracted with the Pacific Northwest National Laboratory (PNNL) to assist in understanding why this variation exists and where it stems from
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PJM Controller Testing with Prototypic PJM Nozzle Configuration
The U.S. Department of Energy (DOE) Office of River Protection’s Waste Treatment Plant (WTP) is being designed and built to pre-treat and then vitrify a large portion of the wastes in Hanford’s 177 underground waste storage tanks. The WTP consists of three primary facilities—pretreatment, low-activity waste (LAW) vitrification, and high-level waste (HLW) vitrification. The pretreatment facility will receive waste piped from the Hanford tank farms and separate it into a high-volume, low-activity liquid stream stripped of most solids and radionuclides and a much smaller volume of HLW slurry containing most of the solids and most of the radioactivity. Many of the vessels in the pretreatment facility will contain pulse jet mixers (PJM) that will provide some or all of the mixing in the vessels. Pulse jet mixer technology was selected for use in black cell regions of the WTP, where maintenance cannot be performed once hot testing and operations commence. The PJMs have no moving mechanical parts that require maintenance. The vessels with the most concentrated slurries will also be mixed with air spargers and/or steady jets in addition to the mixing provided by the PJMs. Pulse jet mixers are susceptible to overblows that can generate large hydrodynamic forces, forces that can damage mixing vessels or their internal parts. The probability of an overblow increases if a PJM does not fill completely. The purpose of the testing performed for this report was to determine how reliable and repeatable the primary and safety (or backup) PJM control systems are at detecting drive overblows (DOB) and charge vessel full (CVF) conditions. Testing was performed on the ABB 800xA and Triconex control systems. The controllers operated an array of four PJMs installed in an approximately 13 ft diameter × 15 ft tall tank located in the high bay of the Pacific Northwest National Laboratory (PNNL) 336 Building test facility. The PJMs were fitted with 4 inch diameter discharge nozzles representative of the nozzles to be used in the WTP. This work supplemented earlier controller tests done on PJMs with 2 inch nozzles (Bontha et al. 2007). Those earlier tests enabled the selection of appropriate pressure transmitters with associated piping and resulted in an alternate overblow detection algorithm that uses data from pressure transmitters mounted in a water flush line on the PJM airlines. Much of that earlier work was only qualitative, however, due to a data logger equipment failure that occurred during the 2007 testing. The objectives of the current work focused on providing quantitative determinations of the ability of the BNI controllers to detect DOB and CVF conditions. On both control systems, a DOB or CVF is indicated when the values of particular internal functions, called confidence values, cross predetermined thresholds. There are two types of confidence values; one based on a transformation of jet pump pair (JPP) drive and suction pressures, the other based on the pressure in the flush line. In the present testing, we collected confidence levels output from the ABB and Triconex controllers. These data were analyzed in terms of the true and noise confidence peaks generated during multiple cycles of DOB and CVF events. The distributions of peak and noise amplitudes were compared to see if thresholds could be set that would enable the detection of DOB and CVF events at high probabilities, while keeping false detections to low probabilities. Supporting data were also collected on PJM operation, including data on PJM pressures and levels, to provide direct experimental evidence of when PJMs were filling, full, driving, or overblowing