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Blade Probe Tool Meets New NRC Requirements for Volumetric RV Head Inspections First-of-a-kind work always carries risks, but when the Nuclear Regulatory Commission (NRC) recommended in August that high-risk plants do an inspection in their fall outage starting in September, there weren't many choices. That is what happened to multiple US nuclear plants. Until the NRC recommendation was issued, most of the reactor vessel (RV) head inspections were visual inspections. However, as a result of the recent findings at the Davis-Besse plant, the NRC determined that more complete inspections were needed. The NRC issued Bulletin 2000-02 on August 9, 2002 recommending that plants with high susceptibility to cracking and leaking of the RV head nozzles perform 100% volumetric blade probe ultrasonic testing (UT) examinations. No one had ever performed 100% volumetric blade probe UT examinations on thermal sleeved nozzles. The blade probes used in the past would not work for this type of inspection. Market Awareness Pays Off Fortunately, Framatome ANP anticipated that the NRC was going to issue another bulletin and that they would require the ultrasonic inspection of the RV head. In fact, the company began work in early June to develop a tool to perform this task. Knowing that the Bulletin would result in a demand for inspections at multiple plants in a short timeframe, Framatome ANP expedited its efforts to perfect the design and to build multiple sets. “The industry required some fast answers to a very difficult problem - complete volumetric interrogation of a complete reactor head penetration set,” commented Steve Huntington, US Vice President Outage Services. “Our NDE engineering group was able to meet the challenge and provide inspection robots for all three PWR designs: Babcock & Wilcox (B&W), Westinghouse (W) and Combustion Engineering (CE) in less than four months. Our customers are benefiting now from this effort as exams are completed and units are returned to service.” Tool Ready for Fall Outages By leveraging French blade tool design technology and incorporating lessons learned from field experience, a new tool was designed, built and tested in roughly three months. To date this fall, Framatome ANP has completed inspections at three plants with others underway. The tool has been proven for use on W and B&W RV heads with thermally sleeved nozzles. In addition, the company designed a similar but different tool used in CE plants this fall. This experience, when combined with the spring 2002 and fall 2001 outage campaigns, establishes Framatome ANP as the most experienced provider of reactor vessel head examination services worldwide. By investing ahead of time and staying engaged in the industry's issues, Framatome ANP had newtooling ready for its customers when they needed it.
New Ultrasonic Tool Reduces Site Support for Reactor Vessel Inspections In the spring of 2003, a new remotely operated manipulator system will be introduced for ultrasonic examinations of PWR reactor vessels. This system, one of the first Framatome ANP projects designed to integrate the strengths of the three regions (France, Germany and the US) will support full 10-year, intermediate and follow-up ultrasonic and visual vessel inspections with minimal disruption of outage activity. Called the Trans-World Reactor Vessel Examination System (TWS), the six-degree-of-freedom robot and all in-containment components can be transported to the canal floor either through the equipment hatch or through most personnel hatches. Once assembled and checked out, the lightweight manipulator can be lowered into the vessel with either an auxiliary crane or with the building polar crane. The manipulator braces itself against the reactor vessel wall, and is ready to begin scanning. Maximum Coverage Provided This innovative manipulator supports maximum weld coverage including remote examinations of the flange surface. Due to the high-speed precision performance coupled with the advanced phased-array Saphir plus ultrasonic testing (UT) acquisition system, the data acquisition can be completed in less time than any existing technology. A US code examination can be completed in approximately two days with no personnel in the building except for supervision of installation and removal, remotely changing transducers for the inner-radius examinations and safety injection or core-flood nozzle examinations. The TWS project includes enhancements to the French Civa Cuve analysis package that facilitates UT data analysis and is required for the French code examinations. The TWS project also includes development of an advanced I&C system that will be integrated into the existing French and German manipulators as well as controlling the new six-degree-of-freedom robot. “The Transworld System will revolutionize PWR reactor vessel examinations,” said Steve Huntington, Framatome ANP's Vice President Outage Services in the US. By combining the engineering and non-destructive examination (NDE) expertise of the three regions, we have designed a tool that will perform complete US vessel exams in less than two days, and provide inspection accuracy never seen before.” TWS: The Tool for Reactor Inspection The TWS reduces vessel occupation time (VOT) and minimizes site resource requirements for ultrasonic examination of reactor vessels. Phased-array technology reduces total scan distances to achieve shorter examination times. The robot's compactness, modularity and configuration flexibility combine to make this one of the easiest and fastest tools to install and remove from the vessel. These innovative features are designed to make the TWS the premier reactor vessel inspection tool of the industry.
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The data herein are solely for your information and are not offered, or
to be construed, as a warranty or contractual responsibility.
© 2003 Framatome ANP. All Rights Reserved. |
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