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| Start date | Reporting criterion | Title | Event description | System | LER | |
|---|---|---|---|---|---|---|
| ENS 51293 | 6 August 2015 04:00:00 | 10 CFR 21.21(d)(3)(i), Failure to Comply or Defect | Part 21 Report - Notification of Deviation Regarding Hk Circuit Breaker Pivot Pin | The following summary was excerpted from a facsimile received from ABB: This letter provides notification of a failure to comply with specifications associated with a pivot pin, part number 193610B00, used in HK circuit breakers. This pin is used as the pivot point for the arcing contacts. Information is provided as specified in 10CFR21 paragraph 21.21(d)(4). Notifying individual: Jay Lavrinc, Vice President & General Manager, ABB (Medium Voltage Service), 2300 Mechanicsville Road, Florence, SC 29501, phone number: (843) 413-4727 Identification of the Subject component: ABB part number 193610B00 pivot pin. This pivot in is used on new legacy HK circuit breakers and during HK breaker refurbishments. The pivot pin is also available as a component item, as part of HK breaker refurbishment kits, and as part of upper terminal contact assemblies. Nature of the deviation: During a breaker refurbishment at the ABB Florence facility, it was noted that a pivot pin cracked at the threads during installation. The peening operation performed on the threaded end of the pivot pin caused cracking due to brittle failure. Laboratory testing revealed that this particular pivot pin was made from an incorrect material. This pivot pin was purchased in April of 2015 and parts from this batch were used between 14 April and 28 May of 2015. There have been no field failures reported at this time. Corrective actions include: a. Removed all remaining pivot pins from stock. (Action complete) b. Contact primary vendor to investigate cause and correct on future orders. (Action Complete) c. Added material verification to our Critical Characteristic cards for future orders. (Action Complete) d. Upgrade of ABB's spectrometer to analyze this silicon bronze material on all future shipments. (Action Complete) e. Obtained and tested, via qualified laboratory, a batch of pivot pins to supply to customers. (Action Complete) f. Notification of the potential existence of this deviation to affected customers (Action to be completed the week of 10 August 2015) Affected Customers: Dominion (Surry Power Station); DTE Energy (Enrico Fermi Power Plant 2); Exelon Corporation (Limerick Generating Station); TVA (Sequoyah Nuclear Plant) Recommendations: If the part was installed in a breaker or assembly and the threaded end did not show signs of failure or fracture at installation, it is not considered to be part of the suspect population. ABB recommends that these pivot pins be visually inspected at the next convenient maintenance cycle. If the pivot pin is in their inventory as a component item or in a kit and was shipped in the time interval of the suspect material, it should be returned to ABB for replacement. | ||
| ENS 45686 | 8 February 2010 05:00:00 | 10 CFR 21.21, Notification of failure to comply or existence of a defect and its evaluation | Potential Failure of a Breaker Component to Comply with Design Specifications | The following information was received via facsimile: A breaker failed during operation at Plant Vogtle during operation. A failure analysis indicated that the resistors on the electronic board fail to an open circuit status. On January 14, 2010, a failure analysis indicated that the resistors fail to a short circuit status prior to failing open. In this failure mode, the internal temperature increases to a point where the plastic core melts and thereby can potentially block the operation of the internal plunger. In such a case, the breaker remains closed, but if the breaker is opened then a new closing command is not possible. ABB is taking, or has taken, the following corrective actions: A. As noted above, the only affected customer with a failed breaker is Southern Company's Nuclear Plant Vogtle, and ABB has discussed this issue with Southern Company. An interim report was issued on 1-18-2010. B. As an interim solution, ABB will provide a standard close coil. This solution will be limited to applications that do not require the low impendence in the close coil for lamp applications. C. An alternate solution is to add 'b' contact (normally closed) in series with the existing close coil. While not having a history of failure, it is noted that similar breakers are used at Plant Hatch. Given the large number of applications for the affected circuit breakers, ABB (Medium Voltage Service) cannot determine if the potential for a substantial safety hazard exists at any licensee's facility if a similar failure of the close coil occurs. As noted above, the failure has been limited to applications that require continuous close coil duty. No failures have been reported or produced in testing in applications with intermittent use of close coil duty. Licensees are requested to evaluate the application of affected breakers to determine priority of close coil replacement.
The identification of the subject component is as follows: ABB PIN ISDA055274Rl Close Coil x Lamp. These close coils are used in Sace EMAX breakers exclusively provided to Southern Nuclear Company plant Vogtle for safety related applications. The close coils are used to release stored energy that in turn closes the breaker. The failure is limited to applications with constant voltage applied to the close coil. Intermittent use of the close coil has not resulted in any failures. ABB Sace EMAX circuit breakers procured from ABB between 2006 to present for Vogtle may have suspect close coils installed where the particular application requires constant control voltage to be applied to the close coil. ABB is taking, or has taken, the following corrective actions: a. As noted above, the only affected customer is Southern Company's Nuclear Plant Vogtle, and ABB has discussed this issue with Southern Company. An initial notification letter was issued on 2-18-2010. b. ABB will provide a standard close coil 1SDA0383013R1. This part number has been updated from the 2-8-2010 notification and is based on ABB Sace input. This solution will be limited to applications that do not require the low impedance in the close coil for lamp applications. | ||
| ENS 45651 | 23 January 2010 05:00:00 | 10 CFR 21.21, Notification of failure to comply or existence of a defect and its evaluation | Circuit Breaker Charging Motor Crank Does Not Meet Hardness Specifications | The following information was received via facsimile: This letter provides notification of a failure to comply with specifications associated with ABB P/N 716532C00 Motor Crank procured as a commercial grade item from Sims Machining, and dedicated by ABB from a production run of 105 pieces produced October 21, 2009. These motor cranks are used in K-Line electrically operated circuit breakers with Ryobi or Wuxi motors. The motor crank is attached to the end of an electric charging motor. When the motor rotates the crank moves the charging pawl assembly in a cyclical manner. The cyclical movement of the charging pawl assembly in turn works with the ratchet pawls and converts the rotational torque produced by the charging motor into linear spring displacement. The linear spring displacement is used to charge the closing springs in the breaker mechanism. Myers Control Power LLC notified ABB Florence on November 25, 2009 of a hardness test failure of motor cranks supplied by ABB for commercial applications. An evaluation was performed by ABB and noted that the required heat treatment process was not performed on a lot quantity of 105 motor cranks received October 24, 2009 from Sims Machining. Of the 105 non-heat treated motor cranks, 100 have been accounted for. Five K-Line circuit breakers procured from ABB between 10/24/2009 and 1/06/2010 may have non-heat treated motor cranks installed. Work process errors allowed non-heat treated motor cranks to be used in manufacture of K-Line circuit breakers. The motor crank is heat treated to prevent the premature wear of the crank as the roller on the crank turns around the output shaft during the charging cycle. The failure to heat treat the motor crank can cause the output shaft of the crank to wear. This will result in the misalignment of the spring charging components or ultimate failure of the spring charging system during the charging cycle, leading to the inability to close the breaker more than once. ABB is taking, or has taken, the following corrective actions: a. Notification of the potential existence of this deviation to affected customers (to complete 1/31/2010). b. Review historical procurement and inspection records associated with the subject part, vendor and similar machined parts requiring heat treatment. (Action complete - no previous heat treatment process errors identified for both commercial and safety-related applications.) c. Follow-up with Sims Machining to determine how future incidents can be prevented and other actions warranted to prevent recurrence. (Action complete - Vendor requires certificate of heat treatment prior to sending to approved supplier for plating services.) d. Remove all non-heat treated motor cranks from inventory and work in progress for rework. (Action complete - 99 of 105 affected motor cranks reworked and 1 motor crank maintained for life cycle testing resulting in 5 suspect motor cranks escaping facility.) e. Revise inspection process instructions to ensure heat treatment is identified as a critical characteristic for verification (to complete by 1/25/2010). f. A cycle test is being performed to determine level of premature wear due to non-heat treatment. Results expected to be complete by 1/31/2010. Given the large number of applications for the affected circuit breakers, ABB (Medium Voltage Service) cannot determine if the potential for a substantial safety hazard exists at any licensee's facility if premature failure of the motor crank occurs. Licensees are requested to evaluate the history of circuit breaker operating cycles to determine if the circuit breaker motor crank should be replaced immediately, or to perform the replacement at the next convenient maintenance opportunity. The HOO spoke to the point of contact for ABB on this issue and determined that the only two reactor licensees likely to have one of these discrepant breakers are Palo Verde and Surry.
ABB has taken the following corrective actions: a. Notification of the potential existence of this deviation to affected customers. (Action complete - notification letters sent 2-1-20 I0) b. Review historical procurement and inspection records associated with the subject part, vendor and similar machined parts requiring heat treatment. (Action complete - no previous heat treatment process errors identified for both commercial and safety-related applications) cycle testing resulting in 5 suspect motor cranks escaping facility) e. Revise inspection process instructions to ensure heat treatment is identified as a critical characteristic for verification. (Action complete) f. A cycle test is being performed to determine level of premature wear due to non-heat treatment. (Action complete) Mechanical life testing of two non-heat treated motor cranks for premature wear was completed. The first crank was measured prior to being installed on the breaker. The output shaft of the crank was measured and found to be 0.370/0.371 before the test began. The breaker was stopped and the crank was removed after 2500, 7500, 10,000 and 12,500 operations. The output shaft was measured and the threaded end of the crank that screws onto the output shaft of the motor was inspected. There was no measurable/noticeable wear in either location. The second crank was measured and installed on the breaker. The output shaft on the crank was measured and found to be 0.370/0.371 before the test began. The breaker was stopped and the crank was removed and measured after 2500,7500, 10,000, 12,500 and at 14,500 operations. No wear was measured during or after the test as a result of thee accumulated operations. The output shaft was measured and the threaded end of the crank that screws onto the output shaft of the motor was inspected. There was no measurable/noticeable wear in either location. After 10,000 operations, it was noted in both cases that the body of the crank showed signs of wear where it comes into contact with the charging assembly. This wear was present as a result of the lack of heat treatment. The wear that was documented during the testing of the motor cranks should not be detrimental to the operation of the breakers. Both of the motor cranks completed the number of mechanical life operations required for certification to the ANSI standard, 12,500. It is recommended that the cranks in question be replaced during the next scheduled availability for the customers affected by this issue. Notified R4 DO (Vincent Gaddy), R2DO (David Ayers), Part 21 Group (email) |