Headquarters Daily Report NOVEMBER 03, 1995 *************************************************************************** REPORT NEGATIVE NO INPUT ATTACHED INPUT RECEIVED RECEIVED HEADQUARTERS û REGION I û REGION II û REGION III û REGION IV û PRIORITY ATTENTION REQUIRED MORNING REPORT - REGION II NOV. 03, 1995 Licensee/Facility: Notification: Florida Power & Light Co. MR Number: 2-95-0092 Saint Lucie 1 2 Date: 11/03/95 Florida Dockets: 50-335,50-389 PWR/CE,PWR/CE Subject: LAYOFFS Discussion: Florida Power and Light Company (FPL) announced yesterday, November 2, layoffs of about 25 employees at the St. Lucie nuclear plants in Fort Pierce, Florida. FLP had announced on November 1 layoffs of about 40 employees at the Turkey Point nuclear plants in Florida City, Florida, and the corporate headquarters in Juno Beach, Florida. The licensee does not plan to issue a press release. There has been media interest. Regional Action: Resident Inspector followup. Contact: R. SCHIN (404)331-5561 _ REGION IV MORNING REPORT PAGE 2 NOVEMBER 3, 1995 Licensee/Facility: Notification: Houston Lighting & Power Co. MR Number: 4-95-0136 South Texas 2 Date: 11/03/95 Wadsworth,Texas Resident Inspectors Dockets: 50-499 PWR/W-4-LP Subject: RESIDUAL HEAT REMOVAL PUMP IMPELLER CRACKING Discussion: On September 26, 1995, while the licensee was replacing the gaskets on the 1C Residual Heat Removal (RHR) pump, maintenance personnel noticed several cracks on the pump impeller. Based on this inspection, on September 27 the pump impeller was replaced, and on September 28 the cracked impeller was shipped to Southwest Research Institute (SwRI) to determine the mechanism of cracking and the cause of failure. The RHR pumps were manufactured by the Pacific Pumps Division of the Ingersoll-Dresser Pump Company. The impellers are designed as radial, single-suction, closed type impellers. The impeller material is martensitic stainless steel (ASTM A296 CA40). The SwRI inspection indicated that the front wear ring had some axial cracks and the front shroud areas had numerous circumferential cracks with some of the cracks extending 100 percent through wall. No cracks were found in the highly stressed areas, such as the impeller hub, key way, or other weld repaired areas on the impeller shroud where the material thickness was adequate. Sectioning the impeller revealed inadequate thickness in the front shroud above the wear ring area where most of the circumferential cracks were located. A finite element stress analysis was performed by the Ingersoll-Dresser Pump Company. Based on the analysis, the vendor found that the impellers should be fully satisfactory for service with shroud thickness greater than or equal to 0.100 inch. The SwRI analysis determined that the impeller became susceptible to circumferential cracking when the casting was weld repaired then over-machined which resulted in inadequate thickness in the radius region. In all regions exhibiting axial cracking, a weld repair and/or a flame hardened surface was present. The weld repair areas had not been properly heat treated after welding. SwRI also determined that the weld material used was wrong, in that it did not match A296 CA-40 requirements. Preliminary results indicated that intergranular cracking was the predominant mode of cracking. Metallurgical evaluation of the axial cracks revealed that the nature of the cracks was intergranular and extend past the heat affected zone of the flame hardened surface. The stress analysis results postulated that a through-wall, circumferential crack existing 360 degrees in the shroud region, would not result in catastrophic failure of the impeller. The results were based on the construction of the impeller in that there is a long section of the impeller vanes that attach the front shroud to the hub. The licensee review of all of the RHR pump differential pressure and vibration trending data did not reveal any indications of degradation on pump performance. Review of the maintenance history revealed that RHR REGION IV MORNING REPORT PAGE 3 NOVEMBER 3, 1995 MR Number: 4-95-0136 (cont.) Pumps 1A and 2A had been visually inspected in 1993 and no cracks were found on the impellers at that time. Based on the information available, the licensee has concluded that the condition identified would have no impact on the operability of the RHR pumps at South Texas Project. Structural Integrity Associates Inc. is currently performing a fracture mechanic evaluation based on stress levels found during the finite element analysis done by Ingersoll-Dresser Pump Co.. The NRC Regional office, NRR, and licensee are continuing to discuss the issue. The unit has recently completed a refueling outage and returned to service. Regional Action: Regional followup is ongoing. The Region and NRR staff will review the fracture analysis report when it is available from the licensee. Contact: J. Pellet (817)860-8183 R. Kopriva (817)860-8104 _ REGION IV MORNING REPORT PAGE 3 NOVEMBER 3, 1995 Licensee/Facility: Notification: Houston Lighting & Power Co. MR Number: 4-95-0137 South Texas 2 Date: 11/03/95 Wadsworth,Texas RESIDENT INSPECTORS Dockets: 50-499 PWR/W-4-LP Subject: PLANT START UP AND RETURN TO SERVICE COMPLETING REFUELING OUTAGE Discussion: On November 2, 1995, at approximately 10:57 a.m. (CST), the licensee closed the generator output breaker, signifying the end of their fourth refueling/maintenance outage. Major activities completed during the outage included reactor refueling, main turbine overhaul, 100 percent inspection of the steam generator tubes, and other plant maintenance. The outage had originally been scheduled for 35 days, and was actually completed in 26 and one-half days. Westinghouse has confirmed that this was a world record for Westinghouse 4 loop plants. The licensee is planning a press release. The plant is currently at 30 percent power and holding while they are reviewing flux mapping results before continuing power ascension. Regional Action: For information only. Contact: J. Pellet (817)860-8183 R. Kopriva (817)860-8104 _