The Application of iphones and ipads to New Medical Services

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1 Issue 17, FALL 2011 The Application of iphones and ipads to New Medical Services By Craig Mauch T he Apple iphone and ipad have taken the world by storm, becoming the favorite Smartphone technology with use in over 80 countries in just a few years. In 2008, Apple launched its first dedicated medical application category, and there has been a flood of interest in using the iphone for medical applications ever since. Early adopters have struggled with the implications of the iphone being a medical device, such as the regulatory implications and formal approval processes required by the FDA. Moreover, this classification also requires that developers maintain quality assurance programs that comply with FDA regulations and employ development processes that follow FDA guidance and industry standards. Software applications for iphone devices- commonly referred to as appscan provide an intrinsic value to the medical community. Medical apps can be used to manage complexity, save time, be more productive, provide better patient care, or enhance the simplicity of information transfers. Benefits to iphone Medical Apps The medical community can benefit from the use of the iphone because it automates many traditional calculations (enhancing reliability), provides improved portability and searching of traditional references, and allows users remote access to medical records. Benefits can be achieved when medical information is portable, personalized, and participatory; it allows users to take control of their desired information. The iphone offers a platform to realize these benefits because of seamless connectivity- the ease with which it can connect to other systems and devices. Additional connectivity can be developed under the Made for iphone program in which custom hardware is connected to the iphone via the 30 pin docking connector. This approach can be used to add other components into a medical system including additional sensors as well as microprocessors that could be used to execute safety critical code without relying on Apple s Commercial Off-The-Shelf (COTS) operating system or software development kit (SDK). Figure 1. Medical Vitals App iphone Apps Regulatory Issues: MPR s Best Practices for Developing Medical iphone Apps Through MPR s involvement with the Made for iphone program and our experience in medical software MPR has developed Best Practices for development of medical software apps. The medical device market is highly regulated. First, Developers should consider the type of iphone application that they are developing carefully to determine if it is indeed a medical device itself, or if it s an accessory to a medical device. The next important step is to determine the medical device classification (Class I, II, III) it will likely receive. Medical software apps can be classified by the FDA in two ways, Medical Device Data Systems (MDDS) or as an actual medical device. According to a February 13, 2011 FDA news release: MDDS are off-theshelf or custom hardware or software products used alone or in combination that display unaltered medical device data, or transfer, store or convert medical device data for future use, in accordance with preset specification. If the medical software app does not fall under the MDDS classification (Class 1 device) then it can be classified as a medical device according to the FDA rules provided by Section 201(h) of the Inside this Issue Application of iphone in New Medical Devices... Maintaining Buried Pipe Integrity Torsional Vibration... Electrical Cable Monitoring What s MPR From the Principal Officer s Desk ( Continued on Page 5 ) Page 1 Page 2 Page 3 Page 4 Page 7 Page 8

2 Maintaining the Integrity of Buried Piping Systems in Aging Nuclear Plants By Phil Rush T he United States currently is home to 104 operating nuclear reactors in 31 states that provide 20 percent of U.S. electricity. As these plants age, maintaining the integrity of buried piping systems is becoming increasingly difficult. This challenge is especially important for systems with safetyrelated functions and systems that contain toxic or radiologically contaminated fluids. In the past decade, the occurrence of several buried pipe leaks resulted in unintended releases to the environment and has engendered much public interest and concern. The NRC now scrutinizes buried piping maintenance programs as part of reviewing requests for operating license extensions. MPR Associates has the knowledge and experience to assist clients with developing and implementing a Life Cycle Management Plan for buried piping systems at nuclear power plants. MPR has worked with utilities on buried pipe specific issues since 2003, and extensively on all types of U.S. nuclear plant designs including BWRs and PWRs. MPR has been involved in troubleshooting engineering problems involving material degradation and system integrity, and our engineers have experience in evaluating the sources and root causes for buried pipe leakage and in Figure 2. Guided Wave UT: Specialized Ultrasonic Inspection Method on Buried developing mitigation strategies. Specifically, MPR s experience includes expertise in: Inadvertent causes of leakage from system boundaries, including problems with design, materials degradation, clogging of drain paths, and improper assembly Architectural features of nuclear plant sites that affect the behavior of inadvertent leakage from buried pipe and its potential for contamination of groundwater Typical mechanisms and pathways for contamination to reach groundwater from buried pipe including understanding the relationship of underground hydrology and potential contaminants Evaluation of buried pipe leak detection, monitoring, and remediation The U.S. nuclear power industry, under the leadership of the Nuclear Energy Institute (NEI), is committed to improving management of buried piping and, to this end, adopted the formal Buried Piping Integrity Initiative in November The Buried Pipe Initiative defines a common approach for managing buried pipe integrity; the specific inspection and maintenance plans for each site are developed locally using the prescribed approach. The Guideline for the Management of Buried Piping Integrity documents the scope and goals, defines roles and responsibilities, including oversight, and defines reporting required to assess progress and experience. The specified approach identifies a six-step process to develop and implement a Buried Pipe Management Program. MPR Associates is well equipped to guide nuclear power plant owners Figure 3. Piping Pig and operators in developing and implementing this process for their plants. The six steps of the process include: 1. Procedures and Oversight Every utility is required to implement a Buried Piping Integrity Program that incorporates the prescribed methodology. Utilities are required to report progress in developing and implementing the Initiative to the Nuclear Energy Institute (NEI) who oversees implementation progress and experience. The Electric Power Research Institute (EPRI) manages research for improving inspection technology for buried pipe, and the Institute for Nuclear Power Operations (INPO) reviews each plant s buried piping program as part of its periodic plant evaluations. 2. Risk Ranking Utilities must identify all buried pipe segments and rank them on the basis of risk, which combines the likelihood of failure with the consequence of failure. Risk ranking is a rigorous process involving Scope Mapping, Data Collection, Indirection Inspections, Likelihood of Failure and Failure Mode Assessment,Consequence Assessment, Risk Analysis and Ranking, and Selection of Inspections. 3. Inspection Based on steps 1 and 2, appropriate 2 ( Continued on Page 5 )

3 Torsional Vibration: A Challenge to Effective Turbine Generator Operability By Amol Limaye T he presence, and potential catastrophic consequences, of torsional vibrations in steam turbine generators rotors has been well established since the first reported failure incidents in the late 1960s and 1970s. However, even with 40 years of experience, the problems associated with torsional vibrations seem to be as prevalent now as ever before. This is especially true given the large number of turbine retrofits that are occurring throughout the industry as utilities try to take advantage of advancements in turbine blade design in order to get increased power output and efficiency. It is clearly an issue that turbine designers, equipment buyers, and plant personnel need to continue to be aware of. To understand how to prevent unacceptable levels of torsional vibration, it is first important to understand what causes them. It is typically assumed that the three-phase currents in a transmission system are balanced, meaning that they are equal in magnitude and phased 120 electrical degrees apart. In reality, there is always some small difference in the magnitude of the phase currents, typically as a result of untransposed transmission lines or unbalanced loads in the distribution system. This electrical phase unbalance can become rather large during grid transients, such as when a lightning strike causes a phase-to-ground fault. The phase unbalance generates negative sequence currents which result in an oscillatory torque being applied to the generator rotor through the air gap between the rotor and stator. During normal operation, the torque is typically 1 to 2% of the full power torque and is continuously present. During a grid fault, the torque magnitude can increase to 50% or greater of the full power torque for a several electrical cycles. Each turbine generator has torsional vibration modes with distinct frequencies and mode shapes. The oscillating torque applied to the generator rotor results in torsional vibration of the entire rotor train, with components such as the large low pressure rotor blades being particularly responsive in the frequency range of interest due to their high inertia and relative flexibility. If one of the torsional vibration frequencies coincides with the frequency of the torque applied from the grid, an amplified vibratory response occurs due to modal resonance. The response due to resonance can be amplified by several orders of magnitude due to the very low torsional damping that is typical for torsional vibration. The large response can result in excessive dynamic stresses in the rotors, couplings, blades, etc., and cause significant damage to the turbine generator. Typical plant instrumentation is not designed to detect torsional vibration. This can result in damage occurring with little or no warning and can often result in costly repairs and loss of generation. Therefore, torsional vibration is an important consideration in the design of turbine generators. To ensure that the vibratory response of the rotor train to a stimulus from the grid has acceptably low magnitude, the frequencies of the torsional modes need to be tuned away from the frequency of the applied torque from the grid. The frequency of the steady state torque due to phase imbalance is equal to two times the line frequency, or 120 Hz for the 60 Hz electrical network in the United States. Standard industry practice recommends that a 2 Hz margin between 120 Hz and the frequency of the nearest torsion mode be maintained to ensure that the rotor train is not vulnerable to damage due to torsional vibration. During a grid fault, a high magnitude torque acts on the generator for a short time. Typically most faults are cleared by circuit breakers within 3 to 6 electrical cycles. Therefore, the high magnitude, short-lived torque appears as an impulse load which results in excitation of all the torsional modes that are excitable through the generator rotor. Consequently, although separation of the torsional mode frequencies from 120 Hz is helpful, it does not provide complete protection from an impulse load from the grid. To protect against a grid fault, turbine generators have to be designed using a combination of tuning and strength. In other words, the turbine life limiting components (typically large LP blade roots) need to have a robust design to sustain several large faults without accumulating significant fatigue damage. Adequate torsional design of a turbine generator requires a combination of analysis and testing. During the Figure 4. Nuclear Turbine Torsional Vibration Spectrum 3 (Continued on Page 6 )

4 Electrical Cable Monitoring & Life Extension Solutions for U.S. Nuclear Power Plants By Brian Curran C ommercial nuclear power plants have a large quantity of electrical cables. In the United States, cables important to plant safety were originally qualified for forty years of service. Industry operating experience indicates that electrical cables are typically more reliable than their terminal components. However, industry operating experience also indicates that the rate of certain types of cable failures has increased in recent years. Cable failures have a variety of causes, including manufacturing defects, damage due to installation, exposure to electrical transients and abnormal environmental conditions during operations. Cable failures require significant repairs, often leading to substantial plant shutdown times. They can also cause plant transients, forced outages, costly repairs, and significant loss in generation. This adverse trend coupled with the extension of plant operating licenses from 40 years to 60 years has required US plants (a) to develop and implement more effective cable aging management programs and (b) to reexamine the original qualification bases for electrical cables. In February 2007, the US NRC issued Generic Letter to licensees at all operating nuclear power plants after reviewing Licensee Incident Reports and determining that main electrical cables were failing earlier than their 40-year life expectancy. The purpose of the Generic Letter was to inform licensees that cable failures can affect the functionally of safety related systems or cause plant transients and the absence of an adequate cable monitoring plan could cause equipment to fail abruptly during service. The letter also requested that licensees provide a history of power cable failures that fall under the scope of 10 CFR and to describe any inspection, testing and monitoring programs implemented by licensees to detect degradation of power cables. The licensee feedback from Generic Letter indicated that actions in the US to mitigate cable failures vary, but generally include more frequent cable inspections and tests to verify cable integrity. However, aging research on electrical cable insulation and jacket polymers indicates that changes in mechanical properties correlate better with cable aging than do the electrical properties of the materials. If plant licenses are extended beyond the current 60 years, large scale replacement of plant cables may be required in order to maintain safe, reliable operation of electrical components. Cable replacement is an alternative to periodic tests and inspections of cables. Some problems with replacing existing cables include cable raceway and tray fill capacity, damage to existing cables caused by installation of new cables, personnel radiation dose, and the cost and time associated with updating plant design documentation and the plant cable database. These concerns add significant uncertainty to the cost estimation of a cable replacement program. However, if significant degradation has been observed cable replacement represents the only option for nuclear plants. MPR, having worked with many nuclear power plant owners and operators, has found that establishing ( Continued on Page 6 ) Figure 5. Cable Failures per Year and Failures per Cable Age 4

5 Application of the iphone In New Medical Devices ( Continued from Page 1 ) Federal Food, Drug and Cosmetic Act. If this is the case then the device will be classified as a Class I, II, or III depending on its level of risk to the user or patient. Depending on the type of iphone app being developed additional hardware may be required. In this case, any hardware that connects to the 30 pin docking connector on the iphone will require approval by Apple as part of their Made for iphone Program. In addition, Apple will require that the iphone app developer meets all industry requirements for medical devices prior to submitting to the App Store or Made for iphone program. Developers should also document software components required for the medical device application to function properly and maintain configuration control over them. That is, be able to uniquely identify them, archive them and ensure that they are used on the iphone device when your medical app runs. This might simply mean determining the ios build version along with the SDK build level. It may also include device type (iphone 4, ipod Touch 4g, ipad(model)). Also, developers should always follow good practices as outlined in the ANSI/AAMI/IEC Medical Device Software- Software Life Cycle Process Guide to create all necessary documentation and reviews needed during the software development process. In Summary iphone interoperability has extended the meaning of communication between medical devices by offering wireless, wired and adaptor technologies to connect to other devices. In a relative short amount of time, Apple s emergence in the medical field has provided developers with a mobile platform capable of running medical applications. This new technology has challenged developers and regulators to keep in pace with new ways to create and regulate medical devices while empowering medical personnel with a variety of robust and high quality information processing capabilities. It is clear that medical apps that run on the iphone are the next tool in providing solutions of breath and intrinsic value. Figure 6. Medical App Maintaining Buried Pipe Integrity ( Continued from Page 2 ) inspection methods are performed on piping segments to determine their condition or need for repair, with priority given to those with the highest risk rank. 4. Fitness-for-Service The fitness for service assessment compares the information obtained regarding piping condition and rate of degradation with the condition needed to ensure satisfactory service. A determination is then made regarding the need and timing for any remedial measures. 5. Repairs Appropriate repair plans for applicable pipe segments are established based on the fitnessfor service assessment. Repair methods should be reviewed against applicable regulatory and license requirements. 6. Prevention, Mitigation and Long-Term Strategy A robust long-range plan for managing the structural and leakage integrity of all buried piping is established and maintained. Key elements of the plan include inspection plans, planned maintenance activities, repair plans, and anticipated replacement plans. This long-term asset management plan is intended to be a living document that is periodically reviewed and updated to reflect experience and insights that are gained. The Buried Pipe Integrity Initiative defines a rigorous method to assess the condition of all buried pipe, and establish prioritized inspection, corrosion 5 mitigation, and repair/replacement plans that will provide reasonable assurance of structural and leakage integrity with special emphasis on systems with the greatest consequence of failure. Through this initiative the U.S. nuclear industry can effectively manage aging buried piping systems significantly reducing the number of buried pipe failures. Figure 6. Application of Coal Tar Impregnated Tape in Field

6 Torsional Vibration ( Continued from page 3 ) design stage, a torsional rotordynamic model of the turbine generator rotor train is developed. The model includes a detailed representation of the torsional inertia and stiffness of rotor train components such as shafts, disks, and couplings. The flexibility of the large LP rotor blades is also included in the model to account for the blade and rotor coupled vibration modes. A modal analysis is performed to determine the torsional mode frequencies and mode shapes. If the model shows that no torsional modes have frequencies within about 6 Hz of 120 Hz, the torsional design is considered adequate. A margin of about 6 Hz by analysis is required to cover typical analysis uncertainties. The required calculation margin can be adjusted up or down on a case-by-case basis depending on the degree of confidence in a given model. If adequate frequency margin from 120 Hz is not predicted by analysis then rotor modifications to shift the torsional natural frequencies away from 120 Hz should be explored. In some cases, Electrical Cable Monitoring ( Continued from page 4 ) and maintaining a cable monitoring program is much more cost effective than wholesale replacement of cables. Additionally, plants undergoing a license renewal must implement a cable testing program for the extended period of plant operation for a limited number of cables that are within the scope of licensee renewal. In response to the information gathered via Generic Letter , the NRC issued Regulatory Guide CR7000 which identified the essential elements of an electrical cable monitoring program and highly recommended that all plants and operators incorporate these the extent of the modifications required in combination with the time available may not allow for rotor modifications to be made prior to the unit being placed in service. A torsional test is then performed during the initial startup of the unit to determine the actual torsional natural frequencies and, if possible, the mode responsiveness. This testing is usually non-intrusive, and can be done through passive monitoring while the unit starts up as it normally would. If the test demonstrates that one or more torsional modes have frequencies within 2 Hz of 120 Hz, a forced vibration response analysis is performed using the computer model of the rotor after it has been calibrated to the measured torsional vibration test data. The analysis evaluates the rotor s response to both expected steady state loads and transient loads from grid faults. If the calculated response is unacceptably high, then the torsional mode frequencies close to 120 Hz are tuned away from 120 Hz by making a physical modification to the turbine generator, such as adding inertia at key locations through installation of a shrunk-on mass ring. The torsional model of the rotor is used to select the elements into their cable monitoring program. Those elements are: 1. Selection of cables to be monitored 2. Development of a database for monitored cables 3. Characterize and monitor service 4. Identify stressors and expected aging mechanisms 5. Select cable monitoring techniques suitable to monitor cables 6. Establish baseline condition of monitored cables 7. Perform test and inspection activities for periodic monitoring of cables 8. Periodic review and incorporating of plant and industry experience 9. Periodic review and assessment of monitored cables condition This program allows for cables to 6 optimal frequency tuning option. MPR started to become significantly involved in torsional vibration design reviews, issue resolution and testing following our involvement in the evaluation and recovery from the catastrophic Maanshan (Taiwan) turbine failure in Today, MPR performs several torsional vibration tests each year, and is actively working with several utilities to avoid or resolve torsional vibration related issues. We have developed our own torsional analysis analytical tools which we have applied successfully to several dozen, if not approaching a hundred, projects over the past twenty plus years. Through MPR s turbine experience, expertise, and engineering services, we are able to provide solutions for both nuclear and fossil plants that ensure turbine generators will continue to function efficiently and with minimal issues to plant operability. We are successfully leveraging our experience from past projects to develop our strengths and reputation as industry experts in turbine generator torsional vibration issues. be qualified using current evaluation methods for 60 years of operation given the appropriate cable monitoring program is put into place. MPR is uniquely capable to assist utilities in developing cable testing programs. MPR engineers are highly familiar with all test methods, preventative maintenance, inspections, and monitoring techniques allowing us to advise our clients on the best way to prevent cable failures. These methods include: Visual inspections of cables, terminations, and tray supports Cable continuity and/or functionality tests Indenter Polymer Aging Monitor (a nondestructive test device that can be used in-situ to measure the compressive modulus of neoprene, Hypalon, and PVC cable jackets to ( Continued on page 7 )

7 Electrical Cable Monitoring ( Continued from page 6 ) identify the degree of hardening) Low-voltage DC testing, including insulation resistance and polarization index High-voltage AC and DC HiPot withstand testing Power frequency testing, which includes partial discharge and power factor tests Time domain reflectometry (TDR) tests Line Impedance Resonance Analysis Very low frequency dissipation factor tests, which includes tangent delta, loss angle, dielectric loss, and power factor testing Water abatement program (visual inspection, dewatering, and level indication and alarms in manholes, duct bank sump pumps, and drainage) Trending Cable issues in the corrective action program For over 20 years, MPR engineers have been working with nuclear plant owners and operators to develop effective cable monitoring and management initiatives. MPR is able to provide our clients with cable monitoring solutions that meet the NRC RG C7000 thereby providing solutions that fully address cable reliability improvements allowing for continued operation in conjunction with plant life extensions. What s MPR Doug Chapin recently provided the opening presentation at the ASME Pressure Vessel and Piping Conference. Dr. Chapin presented an overview of the March 2011 Fukushima Daiichi events including details surrounding the location, technology, chronology, damage, and current conditions. He also provided details on the way forward for the industry, examples of lessons learned, and implications to the design of pressure vessels and piping for critical applications. Dale Driscoll joined MPR in May of this year as Vice President of Federal Services. Mr. Driscoll has over 15 years of executive operations experience in the international, manufacturing, and government services industries. Over the course of Mr. Driscoll s career he has extensively applied his business areas of expertise to working within the Department of Defense, most notably the Department of the Navy and NAVSEA, Department of Energy, specifically DP/NNSA and Department of Homeland Security. MPR is fortunate to have Mr. Driscoll as a highly contributing member of our Federal Service team and is looking forward to continuing to offer our federal clients with products and services that meet their developing industry needs. MPR Product Development Services was the lead host for the AdvaMed 2011 Entrepreneurship Boot Camp which took place September 26 th in Washington, DC. Through a combination of presentations, workshops and panels, attendees were able to learn from a variety of leading CEOs, investors and industry leaders on what works and what to avoid when developing products to ensure their startup s success. Speakers and panelists provided concrete, actionable methods that can be use to increase value from the start of the product s development while minimizing overhead costs and mitigating future risk. Ed Wenzinger and Jason Gwaltney of MPR Federal Services, presented a presentation entitled Value of Technical Reviews of Project, Controls Work Products: a DOE Study at the 23rd Annual International IPM Conference which took place November 7 th -9 th in Bethesda, MD. MPR Federal Service also featured a booth in the main convention hall where conference attendees were able to speak to MPR Federal Service representatives about our paper, our Technical Project Integrator services, and our MPR Federal Services capabilities and qualifications. Energy Services Vice President Tom Lubnow recently organized and chaired two sessions at the 2012 PowerGen Conference hosted in Las Vegas. The sessions addressed major power industry developments and trends in North America, India and China. Project Services Director Bill Dykema also participated in a panel discussion with leading experts on project execution risk management. 7

8 Issue 17, FALL 2011 From the Principal Officer s Desk By Bob Coward In the nuclear energy industry, our responsibility and objective each day is to produce electricity safely. Our industry is committed to operating nuclear facilities effectively and efficiently to ensure the health and safety of the public and our employees while protecting our surroundings. However, the events which occurred in Japan on March 11, 2011 have forced the nuclear energy industry to re-evaluate how we measure industry safety and what new standards and procedures must be implemented moving forward to provide greater accountability for safe operation in the areas we serve. On March 11 th, the Tōhoku earthquake, a magnitude 9 earthquake, occurred off the northeastern coast of Japan resulting in a 45 foot tsunami which hit Eastern Japan. While the majority of plants affected by the earthquake were able to shut down safety, such as the Tokai & Onagawa Nuclear Facilities which were affected by both the tsunami and earthquake, the Fukushima Daiichi Nuclear Facility Units 1-4 suffered major consequences. The disaster damaged not only the normal plant power systems, but also the emergency power systems as well as the connections to the off-site power grid, leaving the nuclear facility without any power for several days. This series of events was well beyond what the facility was designed to handle. The facility structures and systems were severely damaged and the units will never operate again. However, despite those conditions, there were no fatalities at the site resulting from radiation exposure and although there were off-site releases of radiation, the amounts were small. The opportunity, and need, for the nuclear energy industry is to learn from this experience and implement the lessons learned to make our nuclear facilities in the US, as well as around the world, even safer. Fortunately, the underlying values of the nuclear industry include a focus on continuous improvement and sharing experiences. The TMI-2 and Chernobyl accidents each led to improvements in safety at nuclear energy facilities and we are confident that Fukushima will as well. The nuclear industry has a very strong safety record and safety culture; Fukushima will make our industry even safer. Immediately after the Fukushima accident the nuclear industry stepped into action, providing TEPCO with technical support while in parallel looking in-depth at the operating plants to understand potential unforeseen vulnerabilities and weaknesses. Consistent with our leadership role in the nuclear industry, MPR has been a part of those efforts. For example, as an expert on the BWR Mark I containment design (the design of the Fukushima units) as well as nuclear facility electrical distribution systems, MPR has been working with our clients to evaluate the implications from Fukushima and identify the proper actions to best upgrade our existing plants to be even better. We plan to continue our important work supporting our clients as they evaluate and upgrade their facilities. The nuclear energy industry will move forward in the US and around the world through new nuclear facility builds, and enhancement and optimization for current operating facilities. MPR, as with everyone else in the industry, will continue to focus on our abilities to make new and operating plants safer, ensuring that nuclear energy remains a key and important contributor to our society s base load electricity generation as well as a reliable source of clean, emissions-free generation. 320 King Street Alexandria, Virginia