Headquarters Daily report APRIL 26, 1995 *************************************************************************** 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 - REGION I APRIL 26, 1995 Licensee/Facility: Notification: Duquesne Light Co. MR Number: 1-95-0060 Beaver Valley 2 Date: 04/25/95 Shippingport,Pennsylvania Dockets: 50-412 PWR/W-3-LP Subject: TURBINE DRIVEN EMERGENCY FEEDWATER GOVERNOR VALVE STEM BINDING Reportable Event Number: N/A Discussion: Accelerated corrosion of the turbine driven auxiliary feedwater (AFW) pump governor valve stem at Beaver Valley Unit 2 has resulted in governor valve stem binding similar to that recently identified at Calvert Cliffs. Dresser-Rand is the AFW turbine vendor. The stem is a type 410 stainless steel that has a hard nitrided surface layer. Due to the tolerances between the stem and packing assembly, a small buildup of corrosion products will result in binding between the stem and packing. The packing is comprised of carbon discs and stainless steel washers. As discussed in Technical Issue Summary 95-01, Calvert Cliffs identified that new governor valve stems from Dresser-Rand are metallurgically inferior to the older model valve stems. The vendor had reduced the hardness design specification. NRC Information Notice 94-66, "Overspeed of Turbine-Driven Pumps Caused by Valve Stem Binding," only discusses the contribution to binding from dissimilar metals in the packing gland and sulfur impurities in the carbon spacers. The change in the hardness specification is not discussed in the information notice. During the current refueling outage, Beaver Valley replaced the governor valve stem per the vendor's recommendation. The valve stem had been in service for approximately 18 months. The packing gland washers were verified to be the correct type (400 stainless). However, after only three weeks in service, the licensee found the valve stem to be mechanically bound due to the buildup of corrosion products. This was identified during manual stroking of the valve stem. Disassembly of the valve revealed significant pitting on the valve stem. The two valve stems at Calvert Cliffs which failed were in service for only three months each. Beaver Valley believes that the sulfur impurities in the carbon spacers, in combination with a metallurgically inferior valve stem and the natural humidity of the environment, are contributing causes. Options being investigated by Beaver Valley include using low sulfur impurity (less than 700 ppm) carbon washers which were recently made available by Dresser-Rand. Permanent resolution by Dresser-Rand includes the development of an inconel valve stem. However, the availability of an inconel valve stem is projected to be several months. Regional Action: The resident inspectors are monitoring the licensee's corrective actions. Region I is developing a supplement to NRC Information Notice 94-66 to incorporate the change in stem hardening, as identified by Calvert Cliffs, which also contributes to valve binding. Contact: Bill Lazarus (610)337-5231 Pete Sena (412)643-2000 PRIORITY ATTENTION REQUIRED MORNING REPORT - REGION III APRIL 26, 1995 Licensee/Facility: Notification: Nonlicensee MR Number: 3-95-0074 Eastern Iron & Metal Date: 04/25/95 Detroit,Michigan TELECON BY RUST FEDERAL SERVICES Subject: CONTAMINATION AT A METAL SCRAP YARD Reportable Event Number: N/A Discussion: RUST Federal Services, Inc. notified Region III that they would be completing site assessment activities in the Detroit area on Wednesday, April 26, 1995. As a result of the notification, it was learned that radioactive contamination is present at Eastern Iron and Metal. Eastern Iron and Metal collects scrap metal and transports scrap metal to other recycling facilities. A truck load of scrap metal was returned from a recycling facility because the gate alarm detected radiation levels from within the load that exceeded ambient background radiation levels. The date on which this alarm occurred was not reported. Eastern Iron and Metal contacted a local environmental services firm who completed direct radiation surveys of the load and direct radiation surveys within the shipping yard. It was determined that the source of radiation was contaminated soil that was on the surfaces of the scrap metal in the load. The radiation level from a patch of soil (about 5' x 5') in the shipping yard was reported as about 3 millirem per hour. The distance for this radiation level was not specified. The radionuclide(s) involved have not been determined. Eastern Iron and Metal contracted RUST Federal Services, Inc., (NRC License No. 39-25250-01) located in Columbia, South Carolina, to complete confirmation radiation surveys and to collect soil samples to determine the radionuclide(s) involved. These assessments will be completed by a senior health physicist from RUST Federal Services, Inc. on Wednesday, April 26, 1995. Region III has contacted the State of Michigan and NMSS. The State of Michigan may send an HP to Eastern Iron and Metal on Wednesday, April 26, 1995. The State of Michigan will contact the EPA, the lead federal agency at this point. Regional Action: Region III will update this morning report as soon as additional information is received from RUST Federal Services, Inc. Contact: JIM LYNCH (708)829-9818 PRIORITY ATTENTION REQUIRED MORNING REPORT - REGION IV APRIL 26, 1995 Licensee/Facility: Notification: Houston Lighting & Power Co. MR Number: 4-95-0056 South Texas 2 Date: 04/26/95 Wadsworth,Texas SRI Dockets: 50-499 PWR/W-4-LP Subject: TURBINE-DRIVEN AUXILIARY FEED PUMP OVERSPEED Reportable Event Number: N/A Discussion: On April 25, 1995, after completion of scheduled maintenance on turbine-driven Auxiliary Feed Pump 24, the pump was cold started for postmaintenance retest. The pump started and subsequently tripped on an actual mechanical overspeed. The licensee investigated the cause of the mechanical overspeed and determined that galvanic corrosion of the turbine governor valve stem caused stem binding, which prevented the governor valve from closing enough to prevent the overspeed. This event is a repeat of the December 19, 1994, mechanical overspeed of the same pump when the licensee was conducting an inservice test start of the pump. Galvanic corrosion of the governor valve stem was identified as the root cause, identical to the current event. The governor valve was repaired, and the pump was placed on an increased surveillance frequency. Additionally, the licensee initiated a new monthly surveillance (pull test) to disconnect the governor valve linkage and measure the breakaway force and pull force required to close the valve. Industry experience has shown that the nitrited stainless steel valve stem is highly susceptible to this form of galvanic corrosion and that replacement with an inconel stem effectively eliminates the problem. The licensee has replaced the Unit 1 turbine-driven Auxiliary Feed Pump 14 governor valve stem with an inconel stem and plans on similarly replacing the governor valve stem for Pump 24 within the next 4 weeks. As an interim fix, the licensee has repaired the governor valve with a new nitrited stainless steel stem, retested, and declared the pump operable. The licensee will continue to monitor the functionality of the pump by performing the governor valve pull test every 2 days. Regional Action: Region IV will follow up with a special inspection. Contact: William D. Johnson (817)860-8148 Ryan E. Lantz (817)860-8104