NEWS AND VIEWSStructural Integrity Associates, Inc.

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Austin Lab Casebook: Reformer Nozzle

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Structural Integrity Associates analyzed the fractured half of a nozzle from a secondary reformer at a Foster Wheeler designed ammonia plant. The nozzle was specified to be Type 310 stainless steel and had been in service for about 18 years. The fracture was discovered during a turnaround when the nozzle was being prepared for removal.

During visual examination of the nozzle, several secondary cracks were observed on the nozzle section, in addition to the primary fracture. The fracture initiated at the edge of a triangular stiffening bracket and propagated in a brittle overload mode. The fracture surface in the weld area was very dark, and approximately half of the pipe fracture surface also exhibited oxidation, although it was not as dark as at the weld. The other half of the pipe fracture surface appeared to be relatively new and clean, indicating it had probably not been exposed to the operating environment. This all suggests that the fracture initiated

In August 2005, SI completed a five-week training course for four Korea Plant Service & Engineering Co. (KPS) engineers in our San Jose office. The course consisted of lectures and hands-on training in the analyses required to evaluate weld overlay repairs of large bore nozzles in nuclear power plants. This is the fifth training project of this magnitude performed for KPS, and is just one example

Major Training Project for Korean Plant Maintenance Engineers

of the training projects and offerings that SI considers part of its mission to provide services that prevent and control structural and mechanical failures. In addition to the relatively long duration, issue-specific type training course provided for KPS, SI provides shorter courses on more general topics such as corrosion control, Sections III and XI of the ASME

Phased-Array NDE for Generator Shaft Keyway Cracking In Fall 2004 significant cracking was found in the generator shafts of two BWR nuclear units rated at 1180 MWe. The cracking was oriented at a 45° angle relative to the axis of the shaft, consistent with cyclic torsional loading. SI played a lead role in the failure investigation (see the Summer 2005 News and Views) and has recently completed development of a phased-array ultrasonic inspection technique for the early detection of keyway cracking without coupling disassembly.

Crack in Generator Shaft at Keyway under Coupling Shrink Fit

As shown in the figure below, a phased-array, ultrasonic transducer is used to reach the crack initiation location from

the outside surface of the shaft, such that in-situ access for probe placement is possible with minimal disassembly of the oil-deflection shield near the bearing. A compound angle is used along with the beam-sweeping feature of the phased array probe to arrive at the optimal beam

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Schematic of In-Situ Phased-Array Ultrasonic Inspection

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Code, fatigue and fracture mechanics, and plant vibration solutions. A full listing of the courses offered by SI appears at http://www.structint.com/training/. The shorter courses are sponsored by specific utilities for their personnel, or they may be offered at central locations and advertised to the general utility industry on a walk-in fee basis. For example, the corrosion control training course has been provided six times over the past year, four times sponsored by utilities and twice on a walk-in basis. Other courses provided in the past several months or planned for the near future include vibration testing and analysis, and advanced NDE techniques. These courses

(Continued from page 1)Major Training Project...

PRESIDENT’S CORNERBy Laney Bisbee

We are often so immersed in the immediacy of our projects, outages, planning, and day-to-day activities we forget that the electric power industry is an infrastructural cornerstone of our personal lives and economy. This was made vividly apparent through the loss of electricity for days and weeks caused by the hurricanes that have devastated our Gulf Coast region this year and last. As a personal and business consumer dependent on this “product”, I am concerned about where my cheap, uninterrupted electric power will come from in the future.

The majority of fossil plants are now approaching 30 years of service and the nuclear fleet has over 20 years of service on average. Fortunately, large fossil plants are being built, with planned on-line dates within this decade. There are also encouraging reports that several new nuclear units may be sited very soon and targeted for completion well before 2020. However, to get to the time when these new sources are available, there are a few inevitabilities that we as an industry must continue to address – the aging of the current fleet and personnel resources in our industry.

There is evidence to suggest that reliability/performance issues and variability of gas prices could challenge

the economic viability of combined cycle plants. So-called alternate sources (solar, fuel-cells, wave, and wind power) do not appear to be significant contributors to the increasing demand nor will they be replacements for the core generation capacity from continued operation of the fossil and nuclear fleet. Therefore, until new plant construction returns to the historical levels of the late 1970s and early 1980s, we will depend upon the current, albeit aging, fossil and nuclear plants. Maintaining their reliability will require significant resources and technologies.

At the same time, utilities will be designing and building new plants, and should be incorporating the lessons learned from the current fleet in the areas of materials behavior, damage mechanisms, component design, and fabrication. The challenge will be in providing enough resources to the new designs, construction and existing plants to meet all these goals simultaneously. It is apparent that plant operators, designers, fabricators, constructors, research institutions, academia, and consulting firms are all contributing to these efforts. And while it is a challenge that often stretches these resources, SI is excited to be a key contributor.

help utilities fill their general engineering staff training needs and provide specific subject training for target staff groups. Topics being considered for the future include ASME Code, Section XI flaw evaluations for site Level III inspectors, and mini-workshops on current industry topics such as BWR internals.

Customized training is also available on an as-requested basis for any of the areas of expertise available at SI.

For more information, please contact Moses Taylor at (408) 978-8200 or mtaylor@structint.com.

Expanded Analytical Capabilities SI has significantly enhanced our already robust analytical capabilities in several areas with the hiring of Nader Sadeghi (see New People at SI): Probabilistic Risk Assessment (PRA) and Consequence Evaluation: SI now has the capability to perform full power and shutdown PRA for both BWRs and PWRs. This includes fault tree development, event tree development, core damage frequency (CDF) calculations following postulated accidents during full power and shutdown (Modes 3, 4, and 5) conditions, and impact of pipe failures on CDF. SI can also directly support or provide independent review of the periodic updates completed for existing PRA models and analyses based on plant modifications. Nuclear/Thermal Hydraulic Analysis: SI can now perform third party reviews or audits for BWRs in the areas of Stability Analysis; Control Rod Drop Accident (CRDA)/Banked Position Withdrawal Sequence (BPWS) analysis; Transient, LOCA, ATWS, and containment analyses; nuclear kinetics and thermal hydraulic calculations; Radiological Analysis; and head loss and hydraulic sizing calculations for ECCS suction strainers. Our experience includes familiarity with the PANACEA (the BWR core simulator), TRACG, ODYSY, ISCOR, and CONAC computer codes. Reactivity Control Evaluation: SI can now assist utilities in resolving reactivity control issues encountered for BWRs during plant startup, operation, shutdown, and outages; and justify startup and continued operation. Examples include CRDA/BPWS analysis validation for several inserted control rods, sensitivity of rod withdrawal error (RWE) transient analysis to fast control rod withdrawal speed, SRM quadrant re-alignment assessment, clarification of BPWS rules and issues, CRDA/BPWS analysis validation for fully inserted depleted control rod blades, BPWS acceptability for new fuel designs, and effect of EPU on CRDA/BPWS and RWE at startup analyses.

For more information, please contact Nader Sadeghi at (408) 978-8200 or nsadeghi@structint.com.

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SI VibesThe latest from the SI Vibration Group- Very large torsional vibration data sets have been analyzed to help determine the cause of the failures last year on the Dresden main turbines. Torsional data collection and analysis continue at Dresden and Quad Cities. - SI presented a Vibration Short Course at Columbia Generating Station (CGS). Topics included:

- VDAS 3.1 is here. With all channel triggering, the new version of VDAS is an industry-leading tool for piping vibration analysis.

l RCA approach to vibration problem solvingl Test equipment specification and designl Signal processingl Fault diagnostic techniques

- SI provided vibration analysis services to CGS on their HPCS pump motor and Service Water pumps. Our services helped the plant to satisfy operability requirements.- Our first custom data processing software tool has been delivered to Hope Creek.

Created in Matlab, the tool allows rapid reduction of large data sets into desired formats that include time history and frequency spectrum plots.

For more information, please contact Karen Fujikawa at (303) 792-0077 or kfujikawa@structint.com

Failure Analysis of Fan Cooler Unit at Cooper

A drywell fan cooler unit in the Reactor Equipment Cooling (REC) system at Cooper Nuclear Station (CNS) failed recently. Plant personnel observed a spray of water leaking through a tube. The cooler is an air-water heat exchanger that removes heat from the drywell room air (shell side) to the REC closed cooling water on the tube side via multiple, unfinned U-tubes. The copper tubes were brazed into the copper header with a generously applied dose of braze material. A section of the leaking header was removed and cleaned for shipment to SI for this analysis. The as-received section contained the tube with the known leak and sections essentially through the diameter of two other tubes.

SI performed a destructive analysis of the sample to determine the source of the failure. The investigation included detailed visual examination and photographic characterization, and several cross sections to define the nature and probable source of the leak path. Chemical analysis of the component materials was also performed.

Leak in Containment Fan Cooler

Those macroscopic techniques provided the evidence needed to determine the cause of the failure. Since the holes in the header are elliptical due to the header geometry (small cylinders inserted into a larger cylinder at multiple locations), when the tubes are inserted into the header, the gap size will always be different from one side of the tube to the other. As a result, the gaps that the braze material is required to fill will be unequal. The larger gaps will be more difficult to fill and will be more susceptible to flaws. The leak in the braze joint was in a transition zone from the wide gap that was more often observed on the downhill side to the very tight gap on the uphill side.

Except for the leak, the header and the tubes were in excellent condition with no evidence of any damage from corrosion, erosion, or fatigue. The apparent source of the failure was a braze joint defect that was very nearly through wall since fabrication. Heat exchanger service provided the minor degradation required to cause that defect to become a through-wall defect and leak.

For more information, please contact George Licina at (408) 978-8200 or glicina@structint.com

Section at Leak Location

On May 10, Angie and Kasey Kimball welcomed their baby boy Chance into the world. At birth he weighed 8 lbs 3 ounces, and was 20 1/2 inches long.

Damon Priestley’s third daughter was born on October 17. Her name is Anika Mary Priestley. At birth she weighed 7 lbs 11.9 ounces and had a ton of hair.

The SI Family Keeps Growing

Chance Kimball

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at the weld and propagated inward from the weld around the pipe, and that the burner assembly then operated with the crack for some period of time. As indicated by plant personnel, the final fracture occurred after the secondary reformer was shutdown during the most recent turnaround. A cross-sectional sample was cut through the apparent origin area and prepared for metallographic examination. The fracture surface and a secondary crack were primarily transgranular (through grain) and both were covered/filled with oxide, which are characteristics of thermal fatigue. The typical microstructure of the nozzle material, which consists of sigma phase and carbides in an austenite matrix, is typical of Type 310 stainless steel that is sigma phase embrittled. The nozzle fracture and cracking at many of the welds most likely initiated due to thermal fatigue and propagated due to brittle overload because the material was sigma phase embrittled. Sigma phase, which is an iron-chromium compound,

My Tsunami Volunteer Work in South Indiaby Raju Ananth

Ever since my wife was a witness in India to the tsunami that hit south Asia on December 26, 2004, she and I were exploring opportunities to help the victims physically in any way possible. Such an opportunity arose in July to work with a relief organization called Mata Amritanandamayi Math (MATH), whose headquarters are on the southwest coast of India. Nagapattinam in the state of Tami Nadu experienced close to 10,000 human casualties due to the tsunami, the highest on the India peninsula. MATH started relief work soon after the event in all affected areas in India, providing food, clothing, housing, other material items, and social services. Much of my work entailed helping at the HQ office in keeping accounts, answering calls, and visiting the construction sites. Since I can converse in Tamil, the local language, I also taught mathematics to the high school boys and girls at a number

of temporary shelter sites. Contrary to the prevailing US belief, the girls were as interested in math as the boys, if not more. From time to time, the eligible fishermen were given boats and nets. I lent a hand in checking the official records for authenticity before the donations. I even helped drag the donated boats into the sea over the hot sand at 110ºF before going on a joy ride with the elated fishermen!

Reformer Nozzle...(Continued from page 1)

forms in austenitic stainless steels during long periods of exposure to temperatures between approximately 1050 and 1800°F, and results in considerable embrittlement after cooling to ambient temperatures. Since the nozzle was in service for 18 years, SI recommended replacing the nozzle in kind with Type 310 stainless steel and implementing periodic inspections of the weld areas.

For more information, please contact Wendy Weiss at (512) 533-9191 or wweiss@structint.com.

Microstructure with Sigma Phase 400X

Raju (3rd from left) with local fishermen My daily routine involved jogging to the seashore around 6 AM, which is about two miles away from the house where I was staying. On my way back I saw the boats donated by MATH and other organizations anchored at the shore after a night of fishing. I saw the fishermen selling their catch to the middlemen after weighing their booty. In visiting the various temporary shelters and talking to the families, I saw that the emotional impact of the tragedy was decreasing, and the people were looking ahead. They seem to be enterprising, and with a bit of prodding they will overcome their personal losses and lead normal productive lives. About 100 families recently received their permanent housing built by MATH about 75 miles north of Nagapattinam, another area severely affected, with more being built. I did not go with high expectations and hence I was able to adjust to the local needs quickly. I was eating vegetarian food but not as nutritious as I do here in the US. Hence, I did lose about eight pounds during my trip, but my heart was full. My six weeks of total time spent was well worth the money and effort. Such opportunities come our way rarely. The children’s smiles there will forever remain in my thoughts.

For more information, please contact Raju Ananth at (408) 978-8200 or rananth@structint.com.

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angle for detection of very small keyway cracks. The geometric features of this approach have been evaluated analytically and used to design a mockup (which simulates the real shaft keyway geometry) and to test and refine the technique. In-situ inspection of a currently operating generator shaft can be performed on short notice, when the unit is down for even a brief period or during a scheduled refueling outage. In-situ detection of keyway cracking complements SI’s analysis and torsional monitoring tools, providing utilities with a cost-effective alternative to mandatory coupling disassembly per the recent GE TILs 1515-1 and 1516-2 issued to owners of four-pole nuclear generator rotors.

For more information, please contact Darryl Rosario at (408) 978-8200 or drosario@structint.com.

Phased-Array NDE...

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Ken Rach joins SI from Sargent & Lundy, where he worked in Operations & Maintenance Support Services. Other experience includes 20 years with Exelon in various positions related to plant operation and training, both at their corporate offices and at LaSalle Nuclear Station. Ken occupies a cubicle in Exelon’s Corporate Office in Warrenville, Illinois, where he serves as SI’s Client Manager for Exelon.

John Hayden has over twenty-nine years of nondestructive examination field experience, twenty-four of which have been in the commercial nuclear power industry as an NDE Level III. In addition, John has obtained PDI qualifications for piping examination applications, and is an EPRI Qualified NDE Instructor. John’s role at SI includes refining our quality process for supporting nuclear NDE projects, and expanding our presence in the nuclear NDE market.

Bruce Reekie has accepted a full time position as a Senior NDE Specialist in the NDE Services Group working from his residence in Plymouth, Massachusetts. Bruce has been certified by ASNT as a Level III examiner, as well as a Certified Weld Inspector by AWS. In addition to supporting our standard NDE offerings, Bruce brings extensive background and expertise in turbine/generator rotor periphery examinations.

Mary Barber joins our San Jose support staff with over seven years experience in the nuclear industry. Her past employers include Transnuclear West where she supported the Document Control, QA and Human Resources departments. For the past five years, she has been employed with BNFL Fuel Solutions, where she supported the Engineering department, and served as the Office Administrator for the past three years.

Jim Maloney provides IT support for our San Jose office, and has over eight years with financial services companies including Citigroup and H & R Block. His professional certifications include Microsoft, Cisco, and Novell. Jim has a Bachelor’s degree in history from Bradley University, a Masters in Russian history, and a Master of Science in Library and Information Science from the University of Illinois at Urbana.

Allen E. Schuele is a specialist for SI Pipeline Services and is based in SI’s Stonington, Connecticut office. Allen brings nearly 30 years of NDE related experience in the petrochemical, pharmaceutical, and power industries. He has conducted professional seminars addressing various NDE techniques and applications, as well as served as adjunct professor to universities for the purpose of instructing NDE courses.

New People at SIEben Henderson supports our materials assessment efforts as an Engineer in our Connecticut office. Eben is a recent graduate from the University of Maine where he received a B. S. in Mechanical Engineering Technology. At SI, he is applying his background in equipment design and materials testing toward the development and implementation of materials assessment and information technology. Kevin Leypoldt, SI’s Corporate Information Systems Director, has a number of years experience in Information Technology and project management, as well as hands-on experience in the administration of LAN and WAN networks, tech support and telecommunications. Kevin is located in our Denver office.

Jeffry Cavanagh joined the NDE Services Group relocating from Arkansas to Charlotte, North Carolina this summer with his family. Jeff has a Bachelors of Science degree in mathematics and will be supporting the field implementation of our advanced inspection capabilities as an NDE Technician.

John Arnold has joined SI’s Stonington, Connecticut office, focusing on the life prediction of high temperature materials and the integration of our inspection, engineering and financial offerings. John has more than 15 years of experience in the assessment and failure analysis of pressure vessels and power generation equipment.

Jamie Hallmark joined SI this summer as a Senior NDE Specialist working from his residence in Evanston, Wyoming. Jamie has an extensive background in nondestructive testing developed from engagements with his previous employers, and as a previous owner/operator of a radiography company supporting the power and petroleum transmission industries.

Jennifer Smith is an entry-level engineer in SI’s Denver Office. Jenny recently received dual undergraduate degrees in Mathematics and Mechanical Engineering from MIT, and is working on FatiguePro and finite element projects. She is originally from Pennsylvania, so Colorado represents her first experience living in the Wild West.

Christopher Moody is a crew helper for SI Pipeline Services and will be assisting in the G-Scan (Long Range Guided Wave Inspections) pipeline surveys and Ultrasonic B-scan inspections for our refinery and gas transmission clients. Chris may be reached through our Whittier office 562-944-8210.

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Pressurizer Heater SleeveMidwall Repairs

Scott Reekie, a valuable part-time SI employee, friend, and son of Bruce and Joyce Reekie, was tragically killed on May 8, 2005 in an automobile accident in Mississippi. Scott and Bruce have been essential members of the SI family for over six years, unselfishly contributing to the growth and success of SI as a father-son team. Scott was an energetic, hard working young man and we looked forward to many years of friendship and work with him. Our support and prayers are with Bruce and Joyce, his brother, and his fiancée.

In Memoriam: Scott Reekie

Mid-Wall Heater Sleeve Repair

In March 2004, Exelon’s Clinton Power Station (CPS) experienced a main generator trip due to an iso-phase ground fault, resulting in a forced outage. A root cause analysis determined that a piece of aluminum laminate from a bus conductor thermal expansion joint, found in the Iso-Phase Bus Duct (IPBD), could have been a contributing factor in the ground fault. Laboratory analysis concluded that mechanical fatigue, most likely caused by movement due to the cooling airflow, caused the cracking and fracture of the aluminum laminate. Exelon asked SI to evaluate and recommend a clamping approach for these thermal expansion joints. First, an evaluation of five potential clamping alternatives was conducted. The evaluation of each alternative included ANSYS modeling of pressure and thermal expansion loading to compare with the baseline stress results. A fatigue analysis was then completed based on the modeling results. Next, additional design optimization was performed for two of the alternatives plus one additional alternate design proposed by CPS. Finally, a risk ranking of the various expansion joint locations was performed to assist in determining where clamping should be applied if application at all locations cannot be done.

For more information, please contact Bob McGill at (408) 978-8200 or rmcgill@structint.com.

Lamination Welding Alternative

CPS Proposed Alternate Design Installed

Clamping for Iso-Phase Bus Duct Thermal Expansion Joints Working in partnership with Welding Services Inc. (WSI), SI has developed

a mid-wall preemptive heater sleeve repair, which has the advantage of greatly reduced weld volume compared with other repair concepts. The weld buildup at the middle of the pressurizer wall replaces the ID weld as the primary pressure boundary and obviates the need for future repairs. The repair was successfully implemented at two nuclear plants in Spring 2005. SI also developed equipment and procedures for ultrasonic examination of the heater sleeves and repair welds. These multi-channel, automated inspections were also implemented successfully to support the Spring 2005 repair implementations.

For more information, please contact Dick Mattson at (408) 978-8200 orrmattson@structint.com.

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New People at SI ...(Continued from page 5)

Alton (Bud) Auvil is our new Manager of Business Development, working out of our Charlotte office. Prior to joining us, he was Vice President, Product Management at WSI, where he played a key role in our strategic partnering with WSI for Alloy 600 offerings including Preemptive Weld Overlay. Bud has over 20 years of experience in essentially all functional areas of business development and operations.

Eric Nunez has been hired as a field technician assistant for SI Pipeline Services and will be assisting in the Ultrasonic B-scan inspections for our major client, AERA Energy LLC, based in Bakersfield, California. Eric may be reached through our Whittier office.

Cam Tran holds the position of Human Resources Assistant in the Corporate Services Group, and is located in our San Jose office.

Kim Hua has joined our Whittier office. She performs CAD on the formal G-Scan/B-Scan reports and maintains our current client AutoCAD drawings.

Our Austin, Texas laboratory welcomes David Babbitt to SI. David joins us with two years of experience as a metallurgical technician and will be working in the laboratory and in the field.

Nader Sadeghi of our San Jose office previously worked at General Electric, where he specialized in reactivity control, probabilistic risk assessment, nuclear/thermal-hydraulic analysis, stability, contain-ment, LOCA, radiological, finite element analysis, and several other disciplines. He adds some new capabilities to the SI analytical services business area that have previously been available to the utilities only through the NSSS vendor. He has a PhD in Nuclear Engineering from UC Berkeley.

Tiffany Boyd is the new Administrative Assistant for the Charlotte Office. Tiffany is a graduate of the University of North Carolina at Charlotte with a BA in Organizational Communications.

William Justin McKee, known as Justin, has been hired as a crew helper for SI Pipeline Services, working out of our Whittier, California office.

The Service Water (SW) system is a Balance-Of-Plant (BOP) system that provides cooling water to a number of systems throughout a nuclear plant. For plants that have more than one unit, the SW system is typically common to all units. In the fall of 2005 at a two-unit site in the Midwest, water stemming from what was believed to be SW was identified seeping through cracks at various locations on the ground elevation of a common turbine building. This event led to the shutdown of both units. A successful troubleshooting technique used by the plant to identify the leak location for subsequent repair utilized (in

G-ScanTM Used to Locate Water Leaks

part) SI’s G-Scan™ (long range guided wave ultrasonic) technology. The G-Scan™ identified wall loss at a number of areas on a selected run of 54-inch SW piping. This section of SW pipe runs underground from the Cribhouse, through a series of vaults in the Radwaste Building, and then into the Turbine Building. The G-Scan™ accurately identified the axial locations of a number of miter joints and six locations that showed wall thinning, and thus potential locations for a leak. SI also conducted localized internal SW pipe UT examinations utilizing B-Scan (i.e., conventional UT). The B-Scan confirmed the G-Scan™ results. Typically, BOP systems do not receive the same level of inspection as safety related systems. In this event, a dual unit outage was required to allow repair of SW

pipe. Proactively conducting G-Scan™ inspections integrated with other tools such as cathodic protection survey and soil analysis can identify the extent of corrosion and plan related repairs for buried and/or insulated pipe before problems occur.

For more information, please contact Craig Chaney at (303) 792-0077 or cchaney@structint.com.

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...Our Texas and Connecticut Offices Have Moved!

Please make a note of our new address in Austin, Texas and Stonington, Connecticut:

Structural Integrity Associates, Inc.107 Wilcox Road, Suite 107Stonington, CT 06378Phone: 860-536-3982Fax: 860-536-0173