Morning Report for February 5, 2001
Headquarters Daily Report FEBRUARY 05, 2001 *************************************************************************** REPORT NEGATIVE NO INPUT ATTACHED INPUT RECEIVED RECEIVED HEADQUARTERS X REGION I X REGION II X REGION III X REGION IV X PRIORITY ATTENTION REQUIRED MORNING REPORT - HEADQUARTERS FEB. 05, 2001 Licensee/Facility: Notification: MR Number: H-01-0009 Abb Power Date: 02/05/01 Subject: Part 21 - Medium Voltage Circuit Breaker Failures Caused by Material Fatigue in Control Devices Discussion: ABB Power Distribution, a circuit breaker vendor, reported three breaker failures documented at two nuclear power plants since December 1998. The cause of these failures was fatigue of the metal at the base of the spring retainer on the movable contacts, due to insufficient metal mass at the base. In each failure, the broken spring retainer allowed the spring to move out of its intended position, causing failure of the control contacts to make and break properly. The vendor states that the failures were observed at the Sequoyah and Catawba nuclear power plants. The vendor notes that since the HK and K-line type circuit breakers were first marketed in 1960, more than 22,000 such devices have been produced, and that each device had 5 movable contacts. The vendor also noted that from that population of control devices, only these three failures have been reported. The vendor states that for each movable contact, the spring retainer is formed with a die by punching the contact from the opposite side of the electrical contact mounting location. The height of the spring retainer, therefore, determines the amount of material left at the base. The vendor also states that in September, 1979, the spring retainer height was lowered, so that control devices manufactured after that date have more material at the base of the spring retainer than those manufactured before that date. Because movable contacts manufactured before September 1979, would have a small possibility of this type of failure, the vendor recommends that control devices purchased before 1981 be replaced with new control devices on both HK and K-line breakers at the next scheduled breaker maintenance. The vendor states that it will notify all customers who purchased this product. The NRC will post ensuing reports on this subject on its Web site at http://www.nrc.gov/NRC/PUBLIC/PART21/2001. _ REGION III MORNING REPORT PAGE 2 FEBRUARY 5, 2001 Licensee/Facility: Notification: Commonwealth Edison Co. MR Number: 3-01-0003 Quad Cities 1 2 Date: 02/03/01 Cordova,Illinois Phone Call from Licensee Dockets: 50-254,50-265 BWR/GE-3,BWR/GE-3 Subject: QUAD CITIES EMPLOYEE FATALITY Discussion: On February 3, 2001, at 3:48 a.m. a family member discovered an individual slumped over the wheel of his car in the Quad Cities Station parking lot. Emergency medical technicians were called and the individual was pronounced dead at the scene. Cause of death appears to be a heart attack. The individual was employed at the Quad Cities Station as a radiation protection technician. Only minor media interest in the form of an obituary in the newspaper has been noted. Regional Action: The resident inspector was notified by the licensee. Contact: M. Ring (630)829-9703 _
Page Last Reviewed/Updated Wednesday, March 24, 2021
Page Last Reviewed/Updated Wednesday, March 24, 2021