Part 21 2008-0004 - Palisades - Failures of EDG Snubber Valves Licensee/Facility: ENTERGY NUCLEAR OPERATIONS, INC. Palisades COVERT, Michigan Dockets: 05000255 [1] CE License No: Notification: MR Number: H-2008-0004 Date: 03/13/2008 Discussion: On March 13, 2008, the Palisades licensee submitted a Part 21 report on snubber valves (Part Number 2402466) used in the fuel oil distribution system on their ALCO Model 251F emergency diesel generator (EDG; EN 44059). The purpose of the snubber valves is to dampen pulsations created by the fuel injection system and to serve as the fuel oil pressure boundary. This report discusses two failures of these snubber valves since November 2005. The failed snubber valves were made from AISI E 52100 (also denoted ES52100) material but not all the installed snubber valves were constructed of this material. The licensee determined through destructive metallurgical analysis that incorrect selection of AISI E 52100 material during manufacture had resulted in snubber valves that were improperly through-hardened rather than case-hardened, as desired. This condition may allow the snubber valves to crack under operation, resulting in fuel oil leakage and loss of fuel oil supply to the associated engine cylinder. The licensee is replacing affected diesel fuel injection system snubber valves. The first failure occurred on November 20, 2005, when a replacement snubber valve associated with EDG 1-2 cylinder 5R cracked axially in 3 separate locations, causing a fuel oil leak. At the time of failure, the EDG had completed post maintenance runs totaling 11 hours and had completed 1.5 hours of a monthly test (LER 50-255/2005-07). After additional analysis of past operability, the licensee concluded that EDG 1-2 could carry design basis loads and that the leaking fuel oil did not present a fire hazard. Therefore, the licensee concluded that the EDG was operable and cancelled LER 2005-07. The EDG vendor performed an engineering analysis that, in agreement with the licensee, concluded that a substantial safety hazard did not exist. The second failure occurred on February 22, 2007, when another snubber valve, this one associated with cylinder 5L of the same EDG, cracked during a test (LER 50-255/2007-06). This failure occurred after an estimated 135 hours of operation. After discussions with Fairbanks Morse, the manufacturer of this model EDG, the licensee concluded that both failed snubber valves had come from incorrect material lots manufactured prior to 1995. The licensee attributed the presence of the snubber valves in their supply system to inventory practices that did not maintain traceability to purchase orders. The licensee subsequently ensured that all installed snubber valves were from lots manufactured after 1995. In addition, the licensee implemented a receipt inspection technique capable of determining if the snubber valves are made from an incorrect material. The original assessment by Palisades and Fairbanks Morse concluded that the failed snubber valves had been procured prior to 1995 and that the incorrect material was isolated to Palisades. However in January 2008, while the site was replenishing their stock for snubber valves, Palisades receipt inspectors discovered 5 snubber valves from Indian Point that were possibly made from AISI E 52100 material. The licensee sent the snubber valves to an off-site lab and confirmed through destructive testing of one snubber valve that the material from Indian Point was AISI E 52100. Since the Indian Point stock had never been mixed with Palisades stock, Palisades concluded that use of improper material could be a current issue. The licensee provided a snubber valve to Fairbanks Morse for their analysis but that analysis is not complete. NRC staff contacted Fairbanks Morse about these snubber valves. Fairbanks Morse stated that this problem is restricted to the snubber valves, construction material (AISI ES52100), and EDG Model ALCO 251F discussed here. Potentially affected domestic nuclear power plants include Diablo Canyon Units 1 and 2, Ginna, Indian Point Units 2 and 3, Palisades, Pilgrim, and Salem Units 1 and 2. Palisades found that these snubber valves were purchased in 2004. Fairbanks Morse reviewed its shipping and receiving records dated 2004 or later and found none that involved snubber valves constructed of AISI ES52100 alloy. The vendor performs both shipping and receiving tests but not on all valves because material identification requires valve destruction. No similar recent operating experience involving cracked snubber valves was found. Contacts: Name Office Abbrev Phone No E-Mail HODGE, VERNON NRR (301) 415-1861 CVH@nrc.gov Power Reactor Event Number: 43900 Facility: PALISADES Region: 3 State: MI Unit: [1] [ ] [ ] RX Type: [1] CE NRC Notified By: MIKE MLYNAREK HQ OPS Officer: HOWIE CROUCH Notification Date: 01/13/2008 Notification Time: 09:11 [ET] Event Date: 01/13/2008 Event Time: 05:21 [EST] Last Update Date: 01/13/2008 Emergency Class: NON EMERGENCY 10 CFR Section: 50.72(b)(2)(iv)(B) - RPS ACTUATION - CRITICAL 50.72(b)(3)(iv)(A) - VALID SPECIF SYS ACTUATION Person (Organization): DAVID HILLS (R3) Unit SCRAM Code RX CRIT Initial PWR Initial RX Mode Current PWR Current RX Mode 1 M/R Y 100 Power Operation 0 Hot Standby Event Text MANUAL REACTOR TRIP AFTER LOSS OF MAIN FEEDWATER PUMP Palisades Operations staff manually tripped the reactor in accordance with their station's Off-Normal Operating Procedure, after an automatic trip of the "B" Main Feedwater Pump (MFP). The cause of the MFP auto-trip is unknown and being investigated. During the trip, all systems performed as designed. During the transient resulting from the trip, the atmospheric steam dump valves did open momentarily and properly reseated. There is no known primary-to-secondary leakage therefore no release was known to have occurred. All control rods inserted fully as a result of the trip. Auxiliary feedwater pump [AFW] 8A started, as expected, in response to low steam generator water levels experienced during the transient and supplied both steam generators. Decay heat is being removed via the main steam isolation valves to the condenser with the 8A AFW pump supplying feedwater to the steam generators. The plant is at normal temperatures and pressures for this mode. The electrical grid is stable with the station start-up transformer supplying station loads. The licensee has notified the NRC Resident Inspector. Power Reactor Event Number: 43832 Facility: PALISADES Region: 3 State: MI Unit: [1] [ ] [ ] RX Type: [1] CE NRC Notified By: TODD MULFORD HQ OPS Officer: JASON KOZAL Notification Date: 12/10/2007 Notification Time: 22:21 [ET] Event Date: 12/10/2007 Event Time: 18:30 [EST] Last Update Date: 12/10/2007 Emergency Class: NON EMERGENCY 10 CFR Section: 50.72(b)(2)(xi) - OFFSITE NOTIFICATION Person (Organization): JOHN MADERA (R3) Unit SCRAM Code RX CRIT Initial PWR Initial RX Mode Current PWR Current RX Mode 1 N Y 100 Power Operation 100 Power Operation Event Text NOTIFICATION TO OFFSITE AGENCIES DUE TO ELEVATED TRITIUM LEVELS "Five new ground water monitoring wells were recently installed at Palisades Nuclear Plant in support of the Nuclear Energy institute (NEI) ground water initiative. The initial sampling of one of these wells displayed a level of tritium that triggered the communication protocol of the NEI initiative on ground water protection. On December 10, 2007, at 1830 hours, Entergy confirmed that the tritium concentration for this well was 22,000 picoCuries per liter (pCi/l). The threshold for initiating the communication protocol is 20,000 pCi/l (Offsite Dose Calculation Manual limit for drinking water). This well is located inside the owner controlled area and inside the protected area. This well is not a drinking water source. Entergy is continuing to investigate the source of tritium identified in this well. Samples from the remaining four wells are below minimum detectable activity levels. There is no indication that tritium has migrated off the Palisades site. The licensee plans to notify the State of Michigan, Van Buren County Office of Domestic Preparedness, City of South Haven, Covert Township, and the South Haven Charter Township. "The licensee has notified the NRC Resident Inspector." Radioactive groundwater contamination detected at Palisades nuclear facility by: Eartha Jane Melzer Wednesday (12/12) at 11:36 AM Radioactive contamination has been detected in a recently installed monitoring well at the Palisades nuclear power plant, which is located on the shore of Lake Michigan near the city of South Haven and is owned and operated by Entergy. Groundwater samples taken Monday evening showed tritium contamination at a concentration of 22,000 picoCuries per liter, which is above the acceptable level, according to a report filed by the facility with the Nuclear Regulatory Commission. Tritium is a radioactive isotope of hydrogen that combines with oxygen to form tritiated water, also known as super-heavy water. Tritium's half-life -- the amount of time it takes for something to decay to half of its original value -- is 12.3 years. The plant is required to report any tritium concentrations over 20,000 picoCuries per liter, the Environmental Protection Agency's maximum allowable level for drinking water. On Tuesday, plant spokesman Mark Savage notified local officials about the contamination. Savage said the company has no reason to believe that the groundwater contamination has moved off the property, and that the company will continue to monitor the test wells. Lt. Alain Svilpe, director of the Van Buren County Office for Domestic Preparedness, said he was told that the company is investigating the source of the tritium contamination, and that indications suggest condensate from a storage tank. Continued - Eartha Jane Melzer :: Radioactive groundwater contamination detected at Palisades nuclear facility While Palisades is not in a residential area, Svilpe pointed out that campsites at Van Buren State Park, which is directly next to the plant, use well water, and Lake Michigan is a major drinking water source for the region. The Institute for Energy and Environmental Research, a Maryland-based public interest science group, has done a technical analysis of the 20,000 picoCuries per liter federal tritium limit for drinking water and concluded it needs to be strengthened. In a report this February, the group wrote: "Low-energy beta particles, like those emitted by tritium, are often much more effective at causing harm than currently assumed by regulations." IEEE found that most risk analysis focuses on the potential health effects to an adult male, while health effects can be much more pronounced on fetal development. "... tritium can cross the placental barrier. This tritium can then be incorporated into an embryo/fetus and irradiate rapidly dividing cells, thereby raising the risk of birth defects, early miscarriages, and other problems." Tags: environment, EPA, Palisades Nuclear Generating Station, Entergy, South Haven, nuclear energy, groundwater contamination, (All Tags) Print Friendly View Send As Email Radioactive groundwater contamination detected at Palisades nuclear facility | 0 comments | Post A Comment Power Reactor Event Number: 43186 Facility: PALISADES Region: 3 State: MI Unit: [1] [ ] [ ] RX Type: [1] CE NRC Notified By: MICHAEL KANE HQ OPS Officer: JOHN KNOKE Notification Date: 02/25/2007 Notification Time: 17:49 [ET] Event Date: 02/25/2007 Event Time: 13:00 [EST] Last Update Date: 02/25/2007 Emergency Class: NON EMERGENCY 10 CFR Section: 50.72(b)(3)(v)(B) - POT RHR INOP Person (Organization): BRUCE BURGESS (R3) Unit SCRAM Code RX CRIT Initial PWR Initial RX Mode Current PWR Current RX Mode 1 N Y 100 Power Operation 100 Power Operation Event Text DEGRADED ELECTRICAL CABLES TO CCW SYSTEM "On February 17, 2007, it was discovered that cables in a cable tray associated with the Component Cooling Water (CCW) system and Service Water system had sustained external damage by the heat effects from an un-insulated pipe that was in close proximity to the cable tray. "On February 25, 2007, at 1100 hrs, as a result of continued evaluation of the cables in the cable tray and the discovery of a cable with unacceptable cable damage, it was determined that all cables located within the cable tray at the effected zone (that were not already isolated or replaced) were inoperable due to the loss of qualification life and the potential for cable-to-cable interaction from degradation of the cable insulation. This condition could potentially result in spurious equipment operation, causing components to be positioned in other than their desired safety position. "Subsequently, on February 25, 2007, at 1300 hrs, it was recognized that a specific combination of two postulated cable faults could affect the CCW system resulting in a condition where there would be less than 100% of the required CCW post accident cooling capability, per Technical Specification (TS) 3.7.7.C. As a result, TS 3.0.3 was entered. At 1322 hrs, TS 3.0.3 was exited, following isolation of one of the two postulated cable faults, which restored the capability for 100% of the required CCW post accident cooling. "The condition of potentially having less than 100% of the required CCW post accident cooling is reportable per 10 CFR 50.72(b)(3)(v)(B) as a condition that could have prevented the fulfillment of the safety function of structures or systems (CCW system) that are needed to remove residual heat." The licensee notified the NRC Resident Inspector. Power Reactor Event Number: 43351 Facility: PALISADES Region: 3 State: MI Unit: [1] [ ] [ ] RX Type: [1] CE NRC Notified By: TODD MULFORD HQ OPS Officer: STEVE SANDIN Notification Date: 05/08/2007 Notification Time: 15:23 [ET] Event Date: 05/08/2007 Event Time: 13:22 [EDT] Last Update Date: 05/08/2007 Emergency Class: NON EMERGENCY 10 CFR Section: 50.72(b)(2)(iv)(B) - RPS ACTUATION - CRITICAL 50.72(b)(3)(iv)(A) - VALID SPECIF SYS ACTUATION Person (Organization): PATTY PELKE (R3) Unit SCRAM Code RX CRIT Initial PWR Initial RX Mode Current PWR Current RX Mode 1 A/R Y 100 Power Operation 0 Hot Standby Event Text AUTOMATIC REACTOR TRIP ON LOW STEAM GENERATOR WATER LEVEL "On May 8, 2007 at 1322 hours, the reactor automatically tripped from approximately 100% power due to low level in the 'B' Steam Generator. The low level condition resulted from spurious closure of the 'B' feedwater regulating valve. The feedwater regulating valve closure appears related to an instrument and control troubleshooting work activity that was in progress at the time of the event. Investigation into the cause is continuing. "In additions an automatic actuation of the auxiliary feedwater system occurred, as designed, to restore steam generator levels. All systems functioned as designed. Decay heat is being removed via steaming through the turbine bypass valve to the main condenser." All control rods fully inserted. The licensee informed the NRC Resident Inspector. Power Reactor Event Number: 44059 Facility: PALISADES Region: 3 State: MI Unit: [1] [ ] [ ] RX Type: [1] CE NRC Notified By: LAURIE LAHTY HQ OPS Officer: BILL HUFFMAN Notification Date: 03/13/2008 Notification Time: 12:38 [ET] Event Date: 03/13/2008 Event Time: [EDT] Last Update Date: 03/13/2008 Emergency Class: NON EMERGENCY 10 CFR Section: 21.21 - UNSPECIFIED PARAGRAPH Person (Organization): MARK RING (R3) RAY LORSON (R1) MARK LESSER (R2) TROY PRUETT (R4) VERN HODGE (NRR) JOHN THORP (NRR) Unit SCRAM Code RX CRIT Initial PWR Initial RX Mode Current PWR Current RX Mode 1 N Y 100 Power Operation 100 Power Operation Event Text POTENTIAL DEFECT IN FAIRBANKS MORSE EMERGENCY DIESEL GENERATOR SNUBBER VALVE MATERIAL AND HEAT TREATMENT Abstract: "Palisades has experienced failures of two snubber valves on an emergency diesel generator since November 2005. These valves were made from AISI E 52100 material. Entergy has determined through destructive metallurgical analysis that the material was incorrectly heat-treated. Not all of the install snubber valves were constructed of this material. The defect in the material of the snubber valves may allow the snubber valves to crack under operation, resulting in fuel oil leakage and loss of fuel oil supply to the affected cylinder on the engine. Component information: "Manufacturer: Fairbanks Morse Model: ALCO Model 251F ALCO Part Number: 2402466 Description: "Palisades has experienced failures of two snubber valves on the 1-2 emergency diesel generator since November 2005 due to incorrectly heat treated material of the snubber valves. Both snubber valves failed soon after being initially installed in the engine or after being re-installed in the engine after maintenance. The first snubber valve failed after operating for approximately 10 hours of operation. The second snubber valve was installed in the engine and had approximately 135 hours of run time on it before it was removed, inspected and re-installed in the engine. After reinstallation into the engine, the snubber valve failed after approximately 2 hours of operation. Review of the purchasing history of the snubber valves could not identify when these failed snubber valves were originally purchased. "On February 27, 2008, Entergy determined, through destructive metallurgical analysis, that the material that was incorrectly heat-treated was AISI E52100 material. Not all snubber valves were constructed of this material. Subsequently, the receipt inspection practices were revised to include testing of the snubber valves for the suspect material. This is accomplished by using a Niton XLT 800 chemical analyzer to identify (non-destructively) the chemical content of the snubber valves. Snubber valves with manganese contents <0.5% are rejected as they are most likely to be constructed of E52100 material. "In January 2008, five snubber valves were rejected due to not meeting Palisades material requirements. Subsequently, one of the snubber valves was destructively tested and confirmed to have been incorrectly heat treated. These snubber valves were identified to have been purchased in 2004. "A Part 21 evaluation was performed and it was concluded that this is a substantial safety hazard because the defect may allow the snubber valves to crack under operation, resulting in fuel oil leakage and loss of fuel oil supply to the affected cylinder on the engine. The loss of fuel oil supply to a cylinder may affect the ability of the emergency diesel generator to meet its design basis load rating; the external leakage of fuel may result in the potential for a fire to develop and render the diesel generator inoperable; and the leakage of fuel may affect the ability of the fuel oil system to supply adequate fuel oil to the diesel generator throughout its mission time. Causes: "Snubber valves constructed from AISI E52100 material may be incorrectly heat-treated. The cause of this is not known. Corrective Actions: "Palisades experienced two failures, which were reported in Licensee Event Reports 2005-007 and 2007-006. Entergy identified the improper heat treatment following the second failure. Entergy has subsequently replaced all snubber valves on the 1-1 emergency diesel generator. Entergy replaced the defective snubber valve and the remaining snubber valves on the 1-2 emergency diesel generator that had been replaced at the same time the defective snubber was installed. Since the replacement snubber valves on 1-2 emergency diesel generator did not have their material composition verified, eight additional snubber valves were sub replaced after verifying E52100 was not present. Entergy plans to replace the remaining 10 snubber valves on 1-2 emergency diesel generator. Based on the amount of in-service time of these snubber valves and verification of 26 acceptable snubber valves, there is reasonable expectation of operability." The licensee notified the NRC Resident Inspector. Palisades has been in contact with Fairbanks Morse concerning this issue. Power Reactor Event Number: 43351 Facility: PALISADES Region: 3 State: MI Unit: [1] [ ] [ ] RX Type: [1] CE NRC Notified By: TODD MULFORD HQ OPS Officer: STEVE SANDIN Notification Date: 05/08/2007 Notification Time: 15:23 [ET] Event Date: 05/08/2007 Event Time: 13:22 [EDT] Last Update Date: 05/08/2007 Emergency Class: NON EMERGENCY 10 CFR Section: 50.72(b)(2)(iv)(B) - RPS ACTUATION - CRITICAL 50.72(b)(3)(iv)(A) - VALID SPECIF SYS ACTUATION Person (Organization): PATTY PELKE (R3) Unit SCRAM Code RX CRIT Initial PWR Initial RX Mode Current PWR Current RX Mode 1 A/R Y 100 Power Operation 0 Hot Standby Event Text AUTOMATIC REACTOR TRIP ON LOW STEAM GENERATOR WATER LEVEL "On May 8, 2007 at 1322 hours, the reactor automatically tripped from approximately 100% power due to low level in the 'B' Steam Generator. The low level condition resulted from spurious closure of the 'B' feedwater regulating valve. The feedwater regulating valve closure appears related to an instrument and control troubleshooting work activity that was in progress at the time of the event. Investigation into the cause is continuing. "In additions an automatic actuation of the auxiliary feedwater system occurred, as designed, to restore steam generator levels. All systems functioned as designed. Decay heat is being removed via steaming through the turbine bypass valve to the main condenser." All control rods fully inserted. The licensee informed the NRC Resident Inspector. Power Reactor Event Number: 43594 Facility: PALISADES Region: 3 State: MI Unit: [1] [ ] [ ] RX Type: [1] CE NRC Notified By: MIKE MLYNAREK HQ OPS Officer: JEFF ROTTON Notification Date: 08/25/2007 Notification Time: 01:27 [ET] Event Date: 08/24/2007 Event Time: 19:57 [EDT] Last Update Date: 08/26/2007 Emergency Class: NON EMERGENCY 10 CFR Section: 50.72(b)(3)(xiii) - LOSS COMM/ASMT/RESPONSE Person (Organization): JULIO LARA (R3) Unit SCRAM Code RX CRIT Initial PWR Initial RX Mode Current PWR Current RX Mode 1 N Y 100 Power Operation 100 Power Operation Event Text PARTIAL LOSS OF PROCESS COMPUTER PARAMETERS TO ERDS "A portion of the Palisades Plant Process Computer (PPC) including a significant number or Emergency Response Data System (ERDS) trended input became inoperable due to a host computer failure. The cause of the host computer failure is unknown. "Necessary redundant control room parameters exist and are functioning. Palisades is currently in no associated Technical Specification LCOs. "Repair of the host computer will be prudently pursued. NRC notification of repair completion will occur." The licensee notified the NRC Resident Inspector. * * * UPDATE AT 2005 ON 8/26/07 FROM MULFORD TO SNYDER * * * The licensee restored the host computer at 1757 on 8/26/07 so it is now providing accurate data. The licensee notified the NRC Resident Inspector. Notified R3DO (Lara).