SEARCH · Search NASA

Results for “Process Control”

Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.

SourceResearch connectionFrom yearThrough year

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 379 records · Page 21

All sources NASA NTRS DOE OSTI

DOE OSTI2016

Defense Waste Processing Facility (DWPF) Durability-Composition Models and the Applicability of the Associated Reduction of Constraints (ROC) Criteria for High TiO 2 Containing Glasses

Radioactive high-level waste (HLW) at the Savannah River Site (SRS) has successfully been vitrified into borosilicate glass in the DWPF since 1996. Vitrification requires stringent product/process (P/P) constraints since the glass cannot be reworked once it has been poured into ten foot tall by two foot diameter canisters. A unique “feed forward” statistical process control (SPC) was developed for this control rather than relying on statistical quality control (SQC). In SPC, the feed composition to the DWPF melter is controlled prior to vitrification. In SQC, the glass product would be sampled after it is vitrified. Individual glass property-composition models form the basis for the “feed forward” SPC. The models transform constraints on the melt and glass properties into constraints on the feed composition going to the melter in order to determine, at the 95% confidence level, that the feed will be processable and that the durability of the resulting waste form will be acceptable to a geologic repository. The DWPF SPC system is known as the Product Composition Control System (PCCS). One of the process models within PCCS is known as the Thermodynamic Hydration Energy Reaction MOdel (THERMO™). The DWPF will soon be receiving increased concentrations of TiO 2 -, Na 2 O-, and Cs 2 O-enriched wastes from the Salt Waste Processing Facility (SWPF). The SWPF has been built to pretreat the high-curie fraction of the salt waste to be removed from the HLW tanks in the F- and H-Area Tank Farms at the SRS. In order to validate the existing TiO 2 term in THERMO™ beyond 2.0 wt% in the DWPF, new durability data were developed over the target range of 2.00 to 6.00 wt% TiO 2 and evaluated against the 1995 durability model. The durability was measured by the 7-day Product Consistency Test. This study documents the adequacy of the existing THERMO™ terms. It is recommended that the modified THERMO™ durability models and the modified property acceptable region limits for the durability constraints be incorporated in the next revision of the technical bases for PCCS and then implemented into PCCS. It is also recommended that an reduction of constraints of 4 wt% Al 2 O 3 be implemented with no restrictions on the amount of alkali in the glass for TiO 2 values ≥2 wt%. The ultimate limit on the amount of TiO 2 that can be accommodated from SWPF will be determined by the three PCCS models, the waste composition of a given sludge batch, the waste loading of the sludge batch, and the frit used for vitrification.

12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗

DOE OSTI2015

Effect of cooling rate on the properties of high density polyethylene/multi-walled carbon nanotube composites

High density polyethylene (HDPE)/multi-walled carbon nanotube (MWCNT) nanocomposites were prepared by melt mixing using twin-screw extrusion. The extruded pellets were compression moulded at 200°C for 5min followed by cooling at different cooling rates (20°C/min and 300°C/min respectively) to produce sheets for characterization. Scanning electron microscopy (SEM) shows that the MWCNTs are uniformly dispersed in the HDPE. At 4 wt% addition of MWCNTs composite modulus increased by over 110% compared with the unfilled HDPE (regardless of the cooling rate). The yield strength of both unfilled and filled HDPE decreased after rapid cooling by about 10% due to a lower crystallinity and imperfect crystallites. The electrical percolation threshold of composites, irrespective of the cooling rate, is between a MWCNT concentration of 1∼2 wt%. Interestingly, the electrical resistivity of the rapidly cooled composite with 2 wt% MWCNTs is lower than that of the slowly cooled composites with the same MWCNT loading. This may be due to the lower crystallinity and smaller crystallites facilitating the formation of conductive pathways. This result may have significant implications for both process control and the tailoring of electrical conductivity in the manufacture of conductive HDPE/MWCNT nanocomposites.

36 MATERIALS SCIENCE↗

DOE OSTI2012

Co-Design: Fabrication of Unalloyed Plutonium

The successful induction casting of plutonium is a challenge which requires technical expertise in areas including physical metallurgy, surface and corrosion chemistry, materials science, electromagnetic engineering and a host of other technologies all which must be applied in concert. Here at LANL, we are employing a combined experimental and computational approach to design molds and develop process parameters needed to produce desired temperature profiles and improved castings. Computer simulations are performed using the commercial code FLOW-3D and the LANL ASC computer code TRUCHAS to reproduce the entire casting process starting with electromagnetic or radiative heating of the mold and metal and continuing through pouring with coupled fluid flow, heat transfer and non-isothermal solidification. This approach greatly reduces the time required to develop a new casting designs and also increases our understanding of the casting process, leading to a more homogeneous, consistent product and better process control. We will discuss recent casting development results in support of unalloyed plutonium rods for mechanical testing.

CASTING↗

DOE OSTI2016

A mobile system for a comprehensive online-characterization of nanoparticle aggregates based on wide-angle light scattering and laser-induced incandescence

A mobile demonstrator for the comprehensive online-characterization of gas-borne nanoparticle aggregates is presented. Two optical measurement techniques are combined, both utilizing a pulsed Nd:YAG laser as light source. Aggregate size and fractal dimension are measured by Wide-Angle Light Scattering (WALS). An ellipsoidal mirror images elastically scattered light from scattering angles between 10° and 165° onto a CCD-camera chip resulting in an almost complete scattering diagram with high angular resolution. Primary particle size and volume fraction are measured by time-resolved Laser-Induced Incandescence (TiRe-LII). Here, particles are heated up to about 3000 K by the short laser pulse, the enhanced thermal radiation signal is detected with gated photomultiplier tubes. Analysis of the signal decay time and maximum LII-signal allows for the determination of primary particle diameter and volume fraction. The performance of the system is demonstrated by combined measurements on soot nanoparticle aggregates from a soot aerosol generator. Particle and aggregate sizes are varied by using different equivalence ratios of the combustion in the generator. Soot volume fraction can be adjusted by different levels of dilution with air. Online-measurements were carried out demonstrating the favorable performance of the system and the potential for industrial applications such as process control and product development. The particle properties obtained are confirmed through transmission electron microscopy analysis on representative samples.

46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND ↗

DOE OSTI2015

SU-E-T-77: A Statistical Approach to Manage Quality for Pre-Treatment Verification in IMRT/VMAT

Objective: The study presents the application of a simple concept of statistical process control (SPC) for pre-treatment quality assurance procedure analysis for planar dose measurements performed using 2D-array and a-Si electronic portal imaging device (a-Si EPID). Method: A total of 195 patients of four different anatomical sites: brain (n1=45), head & neck (n2=45), thorax (n3=50) and pelvis (n4=55) were selected for the study. Pre-treatment quality assurance for the clinically acceptable IMRT/VMAT plans was measured with 2D array and a-Si EPID of the accelerator. After the γ-analysis, control charts and the quality index Cpm was evaluated for each cohort. Results: Mean and σ of γ ( 3%/3 mm) were EPID γ %≤1= 99.9% ± 1.15% and array γ %<1 = 99.6% ± 1.06%. Among all plans γ max was consistently lower than for 2D array as compared to a-Si EPID. Fig.1 presents the X-bar control charts for every cohort. Cpm values for a-Si EPID were found to be higher than array, detailed results are presented in table 1. Conclusion: Present study demonstrates the significance of control charts used for quality management purposes in newer radiotherapy clinics. Also, provides a pictorial overview of the clinic performance for the advanced radiotherapy techniques.Higher Cpm values for EPID indicate its higher efficiency than array based measurements.

60 APPLIED LIFE SCIENCES↗

DOE OSTI2015

Recent developments in high purity niobium metal production at CBMM

CBMM is a global supplier of high quality niobium products including pure niobium, the focus of this paper. CBMM’s position has been consolidated over three decades of producing high purity niobium metal ingots. The company supplies, among other products, commercial and reactor grade niobium ingots. One of the main uses of CBMM’s ingots is for the manufacture of particle accelerators (superconducting radio frequency – SRF – cavities), where the purity and homogeneity of niobium metal is essentially important for good performance. CBMM constantly strives to improve process controls and product quality, and is currently implementing innovations in production, research and development to further improve ingot quality. The main aim is to reduce the content of interstitial elements, such as nitrogen (N), oxygen (O), carbon (C), and hydrogen (H), starting with the raw materials through the final step of ingot production. CBMM held the first trial to produce the world’s largest-diameter niobium ingot (as cast 535 mm). The results of this initial trial presented very low levels of interstitial impurities (N, O, C, H), allowing the achievement of residual resistivity ratio (RRR) values very close to 300 in a six-melt process in an electron beam furnace. These values were reached with 850 ppm of tantalum. SRF cavities will be produced with this material in order to study the effect of low impurities and high RRR on the Q factor and accelerating gradient.

43 PARTICLE ACCELERATORS↗

DOE OSTI2017

Normal Pulse Voltammetry for Real Time Analysis of Electro-refiner Salt with High Concentrations of Analytes

Spent nuclear fuel pyro-processing could be a preferred alternative for aqueous processing. However, there will be a large hold up of actinides in the molten salt media that must be safeguarded in commercial facilities. A real or near real time monitoring method for electro-refiner salt needs to be developed to meet this requirement. In addition, real time monitoring method can also be applied to optimize process control. Voltammetry would be an ideal method to monitor the ER salt composition because of the low cost and robustness. The equipment required to carry out voltammetry analysis include only a potentiostat and three electrodes, which can be placed in-situ.

12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗

DOE OSTI2019

Current Status of Decommissioning Plans and Chemical Decontamination of Metal Scraps in Chinshan NPP - 19304

The decommissioning of nuclear facilities has become a significantly attractive and worldwide topic due to the end of lifetime of many nuclear power plants within next coming years. In Taiwan, Chinshan nuclear power plant owned by the Taiwan Power Company will be the first candidate to be decommissioned according to the Nuclear Reactor Facilities Regulation Act. The Chinshan nuclear power plant located in New Taipei City has two units of 636 MWe boiling water reactors (BWRs) for the generation of 9 billion kWh of electricity per year. The date of cessation of operation of Unit No. 1 and Unit No. 2 will be December in 2018 and July in 2019, respectively. Based on the Regulations for the Review and Approval of Applications for a Decommissioning Permit of Nuclear Reactor Facilities, Taiwan Power Company have submitted a decommissioning plan of Chinshan nuclear power plant to the authority, Atomic Energy Council (AEC). After the review process, the decommissioning plan of Chinshan nuclear power plant has been permitted by AEC in 2017. Decontamination is generally utilized during the period of decommissioning of nuclear facility in order to minimize the radiation exposure of personnel and the cost of management of radioactive wastes. The successful decontamination also probably provides the benefits of lowering the level of radioactive wastes, facilitating potential releases, permitting the reuse of metals and facilitating the radiation principle of As Low As Reasonably Achievable (ALARA) management. Decontamination aims at the removal of radioactive materials from the contaminated surfaces by several technologies such as washing, heating, chemical reaction and mechanical process. The selection of proper decontamination technologies are depended on the requirement of the target materials and the purpose of the decontamination. Chemical decontamination has been proven to be an effective in reducing the radioactivity for metallic materials by using chemical reagents in contact with the contaminated surfaces. During the operation of Chinshan nuclear power plant, chemical decontamination was performed for Unit No.1 and No.2 in 2000 to decontaminate the Reactor Recirculation System (RRS) and Reactor Water Clean-up Systems (RWCU) by using LOMI-NP-LOMI process. Based on the previous experience of chemical decontamination, the dismantled metallic piping is provided as sample by Chinshan nuclear power plant for the evaluation of the feasibility of chemical decontamination. The provided metallic sample is composed of carbon steel with dose rate around 0.2 mSv/hr. In this report, a multistep decontamination process using strongly oxidizing solution and organic acid solution is performed to remove the contaminated oxide layer from the metal surface, and the resulting contact dose rate and decontamination factor (DF) are also shown to discuss the performance in relation to the process control factors. In this paper, the recent progress in decommissioning programs and preliminary results of the decontamination experiment are described to provide usable information regarding the future decommissioning for Chinshan nuclear power plant. (authors)

12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗

DOE OSTI2019

A Biomedical Ti-35Nb-5Ta-7Zr Alloy Fabricated by Powder Metallurgy

Ti-35Nb-5Ta-7Zr alloy for biomedical applications with a reduced Young’s modulus of less than 10 GPa, being comparable to that of human bones, was successfully fabricated by powder metallurgy method. The microstructure, compressive and tensile behavior were studied. Results indicate that Ti-rich and Ta-rich phases co-exist in β-matrix. Ti-35Nb-5Ta-7Zr alloys yield at about 10% in compression, with increasing in the content of process control agent, the resultant compressive yield strength and Young’s modulus increase from 650 ± 46 to 1055 ± 90 MPa and from 6.3 ± 0.03 to 8.24 ± 0.04 GPa, respectively. The tensile fractography of alloy with 9.7 GPa tensile Young’s modulus, 433 MPa UTS at the 5.5% elongation consists of cleavage fracture and ductile fracture with dimples. The failure mechanism has been discussed taking the intrinsic microstructural features into consideration.

36 MATERIALS SCIENCE↗

DOE OSTI2011

Reducing water freshwater consumption at coal-fired power plants : approaches used outside the United States.

Coal-fired power plants consume huge quantities of water, and in some water-stressed areas, power plants compete with other users for limited supplies. Extensive use of coal to generate electricity is projected to continue for many years. Faced with increasing power demands and questionable future supplies, industries and governments are seeking ways to reduce freshwater consumption at coal-fired power plants. As the United States investigates various freshwater savings approaches (e.g., the use of alternative water sources), other countries are also researching and implementing approaches to address similar - and in many cases, more challenging - water supply and demand issues. Information about these non-U.S. approaches can be used to help direct near- and mid-term water-consumption research and development (R&D) activities in the United States. This report summarizes the research, development, and deployment (RD&D) status of several approaches used for reducing freshwater consumption by coal-fired power plants in other countries, many of which could be applied, or applied more aggressively, at coal-fired power plants in the United States. Information contained in this report is derived from literature and Internet searches, in some cases supplemented by communication with the researchers, authors, or equipment providers. Because there are few technical, peer-reviewed articles on this topic, much of the information in this report comes from the trade press and other non-peer-reviewed references. Reducing freshwater consumption at coal-fired power plants can occur directly or indirectly. Direct approaches are aimed specifically at reducing water consumption, and they include dry cooling, dry bottom ash handling, low-water-consuming emissions-control technologies, water metering and monitoring, reclaiming water from in-plant operations (e.g., recovery of cooling tower water for boiler makeup water, reclaiming water from flue gas desulfurization [FGD] systems), and desalination. Some of the direct approaches, such as dry air cooling, desalination, and recovery of cooling tower water for boiler makeup water, are costly and are deployed primarily in countries with severe water shortages, such as China, Australia, and South Africa. Table 1 shows drivers and approaches for reducing freshwater consumption in several countries outside the United States. Indirect approaches reduce water consumption while meeting other objectives, such as improving plant efficiency. Plants with higher efficiencies use less energy to produce electricity, and because the greater the energy production, the greater the cooling water needs, increased efficiency will help reduce water consumption. Approaches for improving efficiency (and for indirectly reducing water consumption) include increasing the operating steam parameters (temperature and pressure); using more efficient coal-fired technologies such as cogeneration, IGCC, and direct firing of gas turbines with coal; replacing or retrofitting existing inefficient plants to make them more efficient; installing high-performance monitoring and process controls; and coal drying. The motivations for increasing power plant efficiency outside the United States (and indirectly reducing water consumption) include the following: (1) countries that agreed to reduce carbon emissions (by ratifying the Kyoto protocol) find that one of the most effective ways to do so is to improve plant efficiency; (2) countries that import fuel (e.g., Japan) need highly efficient plants to compensate for higher coal costs; (3) countries with particularly large and growing energy demands, such as China and India, need large, efficient plants; (4) countries with large supplies of low-rank coals, such as Germany, need efficient processes to use such low-energy coals. Some countries have policies that encourage or mandate reduced water consumption - either directly or indirectly. For example, the European Union encourages increased efficiency through its cogeneration directive, which requires member states to assess their national potential for cogeneration, analyze barriers to achieving the potential, and then establish support schemes to achieve the potential. China's Eleventh Five-Year Plan (2006-2010) has an energy strategy that specifies, among other things, that production should be optimized by promoting the development of large-scale, high-efficiency units, and that air-cooled technologies should be used in areas with water shortages. The United States lacks many of these drivers. There are no government requirements that mandate more efficient plants. The United States has ample supplies of relatively cheap coal, and U.S. water-short areas are not as extensive as in countries such as China, South Africa, and Australia. Often, other countries have deployed water-savings technologies to a greater degree than the United States.

01 COAL, LIGNITE, AND PEAT↗

DOE OSTI2021

Laser-based Adhesion Strength Measurements for Advanced Manufactured Sensor Adhesion Characterization

As part of the advanced manufacturing (AM) focus of the Nuclear Energy Enabling Technologies (NEET) Advanced Sensors and Instrumentation (ASI) Program, new in-house capabilities to fabricate and test novel active and passive in-pile sensors are being developed at the Idaho National Laboratory (INL). These advanced-manufactured sensors, such as peak temperature monitors and strain gauges, must be miniaturized and be able to provide real-time feedback, all while withstanding the coupled extremes of temperature and radiation typically observed in the environment of a nuclear test reactor. Fabricating durable and robust in-pile sensors with high fidelity requires a fundamental understanding of the optimal process parameters required in the AM technique, as well as the effect of deviations from optimal process parameters on the sensor-substrate adhesion and the ultimate robustness of the sensor. This report presents the use of a laser-based, non-contact approach for characterizing the adhesion of sensors manufactured using aerosol jet printing (AJP) that comprise of silver nanoparticle inks deposited and sintered on austenitic stainless steel (SS) 316L substrates. The effect of substrate surface roughness, surface energy, ink sintering time and sintering temperature on the printed sensor topography and the sensor-substrate adhesion has been systematically investigated. The sensor-substrate interfacial adhesion strength was determined from the critical laser pulse energy required to ablate/ detach the printed sensor from the substrate. Measurements of the sensor topography using optical profilometry revealed that post-deposition sintering at 400°C for 60 minutes resulted in a reduced sensor thickness, while plasma treating the substrate prior to printing yielded sensors with uniform thickness profiles transverse to the print direction. Sintering temperature and time were found to be the dominant parameters that affected sensor-substrate adhesion, followed by substrate surface roughness. The laser-based and locally-destructive approach for adhesion strength measurements shows promise in overcoming the challenges and limitations of current standardized peel tests and can be developed into a post-fabrication process control protocol for evaluating the durability of AM printed sensors in a high throughput fashion. Future studies will investigate the use of laser-induced spallation techniques as well as non-destructive laser ultrasonic methods for sensor-substrate adhesion characterization on sensors manufactured using AJP and other AM techniques such as plasma jet printing (PJP).

42 ENGINEERING↗

DOE OSTI2015

TU-B-304-00: The Aftermath of TG-142

Although published in 2009, the AAPM TG-142 report on accelerator quality assurance still proves a challenge for full clinical implementation. The choice of methodologies to satisfy TG-142 requirements is critical to a successful application. Understanding the philosophy of TG-142 can help in creating an institution-specific QA practice that is both efficient and effective. The concept of maintaining commissioned beam profiles is still found confusing. The physicist must also consider technologies not covered by TG-142 (i.e. arc therapy techniques). On the horizon is TG-198 report on implementing TG-142. Although the community still lacks a final TG-100 report, performing a failure-mode -and-effects analysis and statistical process control analysis to determine the institution-specific clinical impact of each TG-142 test may be useful for identifying trends for pro-active surveillance. Learning Objectives: To better understand the confusing and controversial aspects of TG-142. To understand what is still missing from TG-142 and how to account for these tests in clinical practice To describe which QA tests in TG-142 yield the largest potential clinical result if not discovered.

60 APPLIED LIFE SCIENCES↗

DOE OSTI2014

MO-PIS-Exhibit Hall-01: Tools for TG-142 Linac Imaging QA I

Partners in Solutions is an exciting new program in which AAPM partners with our vendors to present practical “hands-on” information about the equipment and software systems that we use in our clinics. The therapy topic this year is solutions for TG-142 recommendations for linear accelerator imaging QA. Note that the sessions are being held in a special purpose room built on the Exhibit Hall Floor, to encourage further interaction with the vendors. Automated Imaging QA for TG-142 with RIT Presentation Time: 2:45 – 3:15 PM This presentation will discuss software tools for automated imaging QA and phantom analysis for TG-142. All modalities used in radiation oncology will be discussed, including CBCT, planar kV imaging, planar MV imaging, and imaging and treatment coordinate coincidence. Vendor supplied phantoms as well as a variety of third-party phantoms will be shown, along with appropriate analyses, proper phantom setup procedures and scanning settings, and a discussion of image quality metrics. Tools for process automation will be discussed which include: RIT Cognition (machine learning for phantom image identification), RIT Cerberus (automated file system monitoring and searching), and RunQueueC (batch processing of multiple images). In addition to phantom analysis, tools for statistical tracking, trending, and reporting will be discussed. This discussion will include an introduction to statistical process control, a valuable tool in analyzing data and determining appropriate tolerances. An Introduction to TG-142 Imaging QA Using Standard Imaging Products Presentation Time: 3:15 – 3:45 PM Medical Physicists want to understand the logic behind TG-142 Imaging QA. What is often missing is a firm understanding of the connections between the EPID and OBI phantom imaging, the software “algorithms” that calculate the QA metrics, the establishment of baselines, and the analysis and interpretation of the results. The goal of our brief presentation will be to establish and solidify these connections. Our talk will be motivated by the Standard Imaging, Inc. phantom and software solutions. We will present and explain each of the image quality metrics in TG-142 in terms of the theory, mathematics, and algorithms used to implement them in the Standard Imaging PIPSpro software. In the process, we will identify the regions of phantom images that are analyzed by each algorithm. We then will discuss the process of the creation of baselines and typical ranges of acceptable values for each imaging quality metric.

07 ISOTOPE AND RADIATION SOURCES↗

DOE OSTI2015

TU-B-304-01: The Aftermath of TG-142

60 APPLIED LIFE SCIENCES↗

DOE OSTI2015

TU-B-304-02: Quantitative FMEA of TG-142

60 APPLIED LIFE SCIENCES↗

DOE OSTI2024

Contactless Production Testing of Silicon Solar Cells

Critical cost reductions in silicon solar cells are made by minimizing silver usage in their metal contacts. The reason why is both clear and unavoidable—silver is not only expensive, but also a potential limiting resource for scale-up (the PV industry alone used 10.3 % of the global silver supply in 2020 [1]). The result is solar cells with vanishing electrical contact area that are extremely difficult to test prior to module manufacture, when they must be sorted for quality to maximize power output and reliability of the subsequent modules. This project developed a new measurement instrument that enables the transition to solar cells with very low silver content, including cell designs with both minimal busbars and no busbars at all to electrically contact. The resulting instrument at project completion demonstrated the ability to sort cells with comparable—or better—results than existing technology. Compared to existing cell-test instruments, the new tool has minimal contacting requirements, which lowers the maintenance costs and use of consumable parts. We demonstrated innovative, yet pragmatic, solutions for reporting a comprehensive set of measurement results useful for both cell sorting (going forward in the line for module manufacture) and process control (looking backward in the line to identify cell manufacturing issues from wafer to cell-test). In addition to the traditional current-voltage characterization at cell test—short circuit current, open-circuit voltage, power, efficiency and fill factor—the new tool maintains all the advanced parameter characterization of our existing product line such as a substrate doping measurement, carrier recombination (lifetime) analysis, and surface recombination analysis.

14 SOLAR ENERGY↗

DOE OSTI2015

Proof-of-principle demonstration of a virtual flow meter-based transducer for gaseous helium monitoring in particle accelerator cryogenics

A transducer based on a virtual flow meter is proposed for monitoring helium distribution and consumption in cryogenic systems for particle accelerators. The virtual flow meter allows technical and economical constraints, preventing installation of physical instruments in all the needed measurement points, to be overcome. Virtual flow meter performance for the alternative models of Samson [ http://www.samson.de (2015)] and Sereg-Schlumberger [ http://www.slb.com/ (2015)] is compared with the standard IEC 60534-2-1 [Industrial-process control valves—Part 2-1: Flow capacity—sizing equations for fluid flow under installed conditions (2011), https://webstore.iec.ch/publication/2461], for a large temperature range, for both gaseous and liquid helium phases, and for different pressure drops. Then, the calibration function of the transducer is derived. Finally, the experimental validation for the helium gaseous state on the test station for superconducting magnets in the laboratory SM18 [Pirotte et al., AIP Conf. Proc. 1573, 187 (2014)] at CERN is reported.

46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND ↗

DOE OSTI2015

Practical Implementation of Failure Mode and Effects Analysis for Safety and Efficiency in Stereotactic Radiosurgery

Purpose: To improve the safety and efficiency of a new stereotactic radiosurgery program with the application of failure mode and effects analysis (FMEA) performed by a multidisciplinary team of health care professionals. Methods and Materials: Representatives included physicists, therapists, dosimetrists, oncologists, and administrators. A detailed process tree was created from an initial high-level process tree to facilitate the identification of possible failure modes. Group members were asked to determine failure modes that they considered to be the highest risk before scoring failure modes. Risk priority numbers (RPNs) were determined by each group member individually and then averaged. Results: A total of 99 failure modes were identified. The 5 failure modes with an RPN above 150 were further analyzed to attempt to reduce these RPNs. Only 1 of the initial items that the group presumed to be high-risk (magnetic resonance imaging laterality reversed) was ranked in these top 5 items. New process controls were put in place to reduce the severity, occurrence, and detectability scores for all of the top 5 failure modes. Conclusions: FMEA is a valuable team activity that can assist in the creation or restructuring of a quality assurance program with the aim of improved safety, quality, and efficiency. Performing the FMEA helped group members to see how they fit into the bigger picture of the program, and it served to reduce biases and preconceived notions about which elements of the program were the riskiest.

62 RADIOLOGY AND NUCLEAR MEDICINE↗