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Category:ABNORMAL OCCURRENCE REPORTS (SEE ALSO LER & RO)
MONTHYEARML20085F6511976-04-12012 April 1976 Update to AO AO-75-15 Re Containment Air Cooler Temp Control Valve Body Failure.Spare Valve Procurement Requirement Changed from ASME Section III Stds to ANSI B31.1 Stds. Sys Built to B31.1 Std ML20085E7841975-11-14014 November 1975 Telecopy Message Ao:On 751113,CB Exhaust Valves Leaked in Excess of Total Allowable Rate Back Through Inside Valve. Valves to Be Tagged Shut Until Repaired During Next Plant Shutdown ML20085E7971975-10-30030 October 1975 Telecopy Message Ao:On 751029,interchanged W Prime Curves Resulted in Nonconservative Heat Rate Calculation for Core Limiting Assemblies.Caused by Improper Conversion of Flux to Power by Inca Power Distribution on 730619 ML20085E8231975-10-24024 October 1975 AO 75-024:on 751015,thermal Discharge of Blowdown from closed-cycle Cooling Sys Found Above Permissible Temp Limit. Caused by Shutoff Dilution Pumps During Installation of New Thermal Discharge Monitoring Equipment.Procedure Revised ML20085E8081975-10-15015 October 1975 Telecopy Message Ao:On 751015 Discharge Water Temp Exceeded Tech Spec Limits by 5 Degrees During Temp Monitoring Equipment Installation ML20085F7071975-09-19019 September 1975 Updated AO AO-74-11 Revising Analysis of Occurrence.Loss of Dc Control Power to Bus 1D Feeder Breaker 72-203 Results in Breaker Not Being Able to Operate If Equipment Malfunctions ML20085E8721975-09-18018 September 1975 Telecopy Message AOs 75-022 & 75-021:boron Concentration Found Below Tech Spec Limits & HPSI Safety Injection Valve Found W/Apparent Disc Separation.Valve MOV-3007 to Be Disassembled & Evaluated.Investigation Continues ML20085E8811975-09-15015 September 1975 Telecopy Message Aos:Safety Tank Boric Acid Concentration Found Below Tech Spec Limits & HPSI Valve MOV-3007 Failed. Further Info Will Be Submitted ML20085F7201975-09-0909 September 1975 AO 75-019:on 750830,control Rod 11 Dropped Into Core.Caused by Shorted Clutch Coil.Clutch Replaced ML20085F6891975-09-0808 September 1975 Telecopy Message of AO 75-020:on 750905,control Rod 16 Dropped.Flux Tilt & Ejected Rod Worth Resulting from Dropped Rod within Tech Spec Limits.Clutch Coil Replaced ML20085F7491975-08-28028 August 1975 AO 75-018:on 760817,control Rod 19 Dropped Into Core.Caused by Shorted Clutch Coil.Clutch Replaced.Preventive Maint,To Include Insulation & Component Resistance Measurements on Control Rod Drive Mechanisms,To Be Evaluated ML20085F7671975-08-18018 August 1975 Telecopy AO 75-018:on 750817,control Rod 19 Dropped Into Core.Caused by Shorted Clutch Coil in Control Rod Drive Mechanism ML20085F7961975-08-12012 August 1975 AO 75-016:on 750722,radwaste Batch 75-021 R Discharge Rate Exceeded.Caused by Inaccurate Flow Control Due to Water Loss in One Leg of Flow Controller FIC 1050.Radwaste Release Procedures Revised ML20085F7721975-08-12012 August 1975 AO 75-017:between 750718-28,waste Gas Decay Tank T 101C Lost Pressure.Probably Caused by Small Valve Leak.Tank Will Be Monitored During Next Period of Use Since Tests Did Not Determine Pressure Drop Cause ML20085F8731975-07-25025 July 1975 Telecopy Ao:On 750716,util Water Storage Tank T-91 Removed from Svc to Replace Liner Coating ML20085F8041975-07-24024 July 1975 Telecopy AO 75-016:radwaste Batch Discharge Rate Exceeded During Release of Radwaste Batch 75-021-R.Caused by Malfunctioning Flow Controller FIC 1050 ML20085F8631975-07-22022 July 1975 Telecopy Ao:On 750719,MOV-3011 Functioned Improperly During QO-1 Test.Caused by Failure of Spring Return Switch,Ge Type CR 2940 ML20085F3581975-07-11011 July 1975 AOs AO-75-6,AO-75-7 & AO-75-13 Have Been Canceled.Tech Specs Re Heated Discharge Do Not Apply to Svc Water Sys or Other Discharge ML20085F9101975-07-0808 July 1975 AO 75-014:on 750630,bus 1D Failed to Transfer from Station Power to Startup Power.Caused by Failure of Incoming Breaker 152-202 to Close Automatically Due to Diesel Generator Breaker 152.213 Interlock.Synchrocheck Circuitry Repaired ML20085F9271975-07-0202 July 1975 AO 75-014 & RO 75-004:on 750701,bus 1D Failed to Fast Transfer from Station to Startup Power & Control Rod 38 Deviated by 9 Inches,Respectively.Ao Caused by Faulty Auxiliary Contact.Ro Caused by Shorted Capacitor ML20085F9151975-07-0202 July 1975 Telecopy Message AO 75-014:on 750701,bus 1D Failed to Transfer from Station Power to Startup Power.Caused by Faulty Auxiliary Contact on Incoming Bus Breaker.Ro 75-004, on 750701,control Rod 38 Deviated Due to Capacitator Short ML20085F9501975-06-30030 June 1975 AO 75-013:on 750619,plant Discharge Water Temp & Heat Rate Exceeded Tech Spec Limits.Caused by Changing Lower Basin Level.Addl Operating Procedures to Be Formulated for Raising & Lowering Cooling Tower Basin Levels ML20085F9601975-06-23023 June 1975 Telecopy AO 75-013:on 750619,mixing Basin Outfall Exceeded Lake Temp Differential While Adjusting Cooling Tower Makeup to Allow Evaporation Changes.Details Will Follow ML20085F5821975-06-18018 June 1975 Updated AOs AO-21-74,AO-6-75 & AO-7-75,in Response to 750512 Request for Addl Info.Cause of Failure of Diesel Generator 1-1 Air Start Motor Not Determined ML20085F9761975-06-13013 June 1975 AO 75-012:on 750603,required Measurements & Observations Re Closed Cycle Condenser Cooling Sys Chlorination Treatment Not Performed.Caused by Incorrectly Conceived Tech Specs ML20085F9961975-06-0606 June 1975 Telecopy Message AO 75-012:on 750606,difficulty Encountered in Adhering to Tech Spec Section 3.9.7-3.9.9 Re Cooling Tower Chlorination Limits ML20085F9991975-05-30030 May 1975 Telecopy AO 75-011:on 750529,overpower Trip Setpoint on NI005 Found Out of Spec During Surveillance Test MO1 ML20085F3251975-04-28028 April 1975 AO AO-75-9:on 741223,three Reactor Trip Pressure Switches, PS-1801,PS-1802 & PS-1803 Found Out of Calibr.Caused by Use of Incorrect Procedure for Switch Calibr.Instrument Index Revised to Ref Proper Tech Spec Section ML20085F3221975-04-23023 April 1975 AO AO-10-75:on 750413,in-core Readings on Primary Data Logger Failed to Update.Caused by Deficient Software Program.Program Being Analyzed to Find & Correct Deficiency ML20085F3341975-04-18018 April 1975 Telecopy AO AO-75-8:three Containment High Pressure Switches Found Out of Calibr ML20085F3281975-04-17017 April 1975 AO AO-75-8 Has Been Canceled.Review of Temp Measuring Techniques Disclosed Temp Measurements in Error.Revised Measurements Show Discharge Temp within Allowable Limits ML20085F3771975-04-16016 April 1975 AO AO-75-7:on 750406,plant Discharge Effluent Heat Rate & Discharge Temp Increase Found Greater than Tech Spec Limits. Apparently Caused by Plant Procedure Problems & Beginning Operation of Newly Installed Closed Cycle Cooling Sys ML20085F3981975-04-14014 April 1975 AO AO-75-6:on 750404,plant Discharge Effluent Heat Rate Exceeded Tech Specs.Apparently Caused by Plant Procedure Problems & Beginning Operation of Newly Installed Closed Cycle Cooling Sys ML20085F4201975-04-11011 April 1975 AO AO-75-5:on 750411 Unsampled South Filtered Waste Tank W/Laundry Waste Released.Caused by Use of Wrong Batch Card. Tank Release Terminated Until Appropriate Analysis Could Be Made ML20085F3441975-04-0808 April 1975 AO AO-75-8:from 750406-07,indicated Temp of Mixing Basin Discharge More than 5 F Above Indicated Temp of Plant Intake Water.Caused by Excess Amount of Water Going Over Cooling Tower Pump Makeup Basin Overflow ML20085F4271975-04-0707 April 1975 Telecopy AO AO-75-5:on 750401,unsampled Liquid Waste Tank of Laundry Waste Released.Caused by Two Tank Analyses on Same Tank.Tank Release Stopped & Analysis of Tank Contents Made. Tank Released on 750403 ML20085F3881975-04-0606 April 1975 Telecopy AO AO-75-7:on 750406,plant Discharge Effluent from Mixing Basin Exceeded Tech Spec Limit.Caused by Cracking Open of Condenser Inlet Valve MOV-5301 to Reduce Hotwell Temp to Avoid Thermal Shocking Condenser Tubes ML20085F4081975-04-0404 April 1975 Telecopy AO AO-75-6:on 750404,plant Discharge Effluent Heat Rate Exceeded Tech Specs.Caused by Diversion of Dilution Water Through Unused Side of Condenser.Personnel Unaware of Difference in Temp Between Inlet Water & Basin Outfall ML20085F4511975-03-27027 March 1975 Update to AO AO-4-75,revising Analysisi of Occurrence.Util Discovered 102 restraints,12 Restraint Replacements & 74 Restraint Mods Required or Added for Addl Conservatism. Sys Studied Listed ML20085F4561975-03-17017 March 1975 AO AO-4-75:on 750307,util Determined Certain Seismic Class I Piping Sys Restraints Do Not Comply W/Fsar Design Criteria. Investigation Into Cause Underway.Sys Studied Listed ML20085F5181975-02-0404 February 1975 AO AO-2-75:on 750126,vol Control Tank Gas Lost to Auxiliary Bldg.Caused by Bank Pressure Due to Venting of Vol Control Tank Which Blew Loop Seal on Evaporator Vacuum Pump Air Water Separator ML20085F5091975-02-0404 February 1975 AO AO-3-75:on 750122,leak in Component Cooling Water to Svc Water Header Discovered.Cause Not Stated.Leak Developed 750116.Leaking Tube Plugged ML20085F5231975-01-31031 January 1975 AO AO-75-1:on 741206,allowable Leak Rate Exceeded on Purge Air Supply Valve CV-1808 During Test.Caused by Lack of Sufficient Lubricant Aggravated by Unusual Svc Condition. Packing Properly Greased & Leakage Reduced ML20085F5151975-01-28028 January 1975 AO Telecopy 75-2:on 750126,vol Control Tank Gas Lost to Auxiliary Bldg.Caused by Discharge of Orificed Recirculation Line from Vacuum Pump Back to Evaporator,Causing Erratic Evaporator Operation ML20085F5061975-01-26026 January 1975 AO 75-3:on 750122,leak Suspected in One Component Cooling Water Hx.Component Cooling Water a Isolated.Leak Developed on 750116.Caused by Leaking Tube.Tube Plugged ML20085F5361974-12-26026 December 1974 AO AO-28-74:on 741215,north Filtered Waste Tank of Laundry Waste Released W/O Prior Sampling.Caused by Technician Error.Wrong Tank Identification Wrote on Batch Card When Transposing Data ML20085F5391974-12-17017 December 1974 Telecopy AO AO-74-28:on 741215,north Filtered Waste Tank of Laundry Waste Released W/O Prior Sampling.Caused by Technician Error.Technician Wrote Down Incorrect Tank Identification on Batch Card ML20085F5471974-12-12012 December 1974 AO AO-27-74:on 741130,released to Plant Vent Stack from Waste Gas Surge Tank.Caused by Waste Gas Surge Tank Leakage, Due to Leaky Relief Valve.Valve Repaired & Pressure Tested ML20085F5521974-12-0202 December 1974 AO AO-74-27:on 741130,waste Gas Surge Tank Vented to Plant Stack.Continuous Stack Monitor Alarmed.Caused by Malfunction of Waste Gas Surge Tank Pressure Relief Valve.Total of 40 Mci Released in 3 Cubic Meters Radioactive Gases ML20085F5291974-11-18018 November 1974 Updated AO AO-24-74 Re Greater than Allowed Ph Difference Between Lake Inlet & Outlet Water.Caused by Cooling Tower Acid Injection Sys Continuing to Operate After Pump Shut Off Due to Incorrect Relocation of Sample Probe 1976-04-12
[Table view] Category:TEXT-SAFETY REPORT
MONTHYEARML18066A6901999-11-0101 November 1999 Rev 5 to Palisades Nuclear Plant Colr. ML18066A6761999-09-30030 September 1999 Monthly Operating Rept for Sept 1999 for Palisades Nuclear Plant ML18066A6271999-09-0202 September 1999 LER 98-011-01:on 981217,inadequate Lube Oil Collection Sys for Primary Coolant Pumps Was Noted.Caused by Design Change Not Containing Appropriate Level of Rigor.Exemption from 10CFR50,App R Was Requested.With 990902 Ltr ML18066A6351999-08-31031 August 1999 Monthly Operating Rept for Aug 1999 for Palisades Nuclear Plant ML18066A6771999-08-31031 August 1999 Operating Data Rept Page of MOR for Aug 1999 for Palisades Nuclear Plant ML18066A6221999-08-20020 August 1999 LER 99-002-00:on 990722,TS Surveillance Was Not Completed within Specified Frequency.Caused by Failure to Incorporate Revised Frequency Into Surveillance Schedule in Timely Manner.Verified Implementation.With 990820 Ltr ML18066A6061999-07-31031 July 1999 Monthly Operating Rept for July 1999 for Palisades Nuclear Plant.With 990803 Ltr ML18066A5201999-06-30030 June 1999 Monthly Operating Rept for June 1999 for Palisades Nuclear Plant.With 990702 Ltr ML18066A4841999-05-31031 May 1999 Monthly Operating Rept for May 1999 for Palisades Nuclear Plant.With 990603 Ltr ML18066A6371999-04-30030 April 1999 Revised Monthly Operating Rept for Apr 1999 for Palisades Nuclear Plant ML18068A5941999-04-30030 April 1999 Monthly Operating Rept for Apr 1999 for Palisades Nuclear Plant.With 990503 Ltr ML18066A4161999-04-0101 April 1999 Rev 4 to COLR, for Palisades Nuclear Plant ML18066A4501999-03-31031 March 1999 Monthly Operating Rept for Mar 1999 for Palisades Nuclear Plant.With 990402 Ltr ML18066A4671999-03-31031 March 1999 Rev 0 to SIR-99-032, Flaw Tolerance & Leakage Evaluation Spent Fuel Pool Heat Exchanger E-53B Nozzle Palisades Nuclear Plant. ML18068A5351999-02-28028 February 1999 Monthly Operating Rept for Feb 1999 for Palisades Nuclear Plant.With 990302 Ltr ML18066A3931999-01-31031 January 1999 Monthly Operating Rept for Jan 1999 for Palisades Nuclear Plant.With 990202 Ltr ML18066A3781999-01-20020 January 1999 LER 98-013-00:on 981222,safeguards Transfer Tap Changer Failure Caused Inadvertant DG Start.Caused by Failed Motor Contactor.Contactor Was Replaced.With 990120 Ltr ML20206F6131998-12-31031 December 1998 1998 Consumers Energy Co Annual Rept. with ML18066A3651998-12-31031 December 1998 Monthly Operating Rept for Dec 1998 for Palisades Nuclear Plant.With 990105 Ltr ML18066A3421998-11-30030 November 1998 Monthly Operating Rept for Nov 1998 for Palisades Nuclear Plant.With 981202 Ltr ML18066A3301998-11-11011 November 1998 Part 21 Rept Re Potential Safety Hazard Associated with Wrist Pin Assemblies for FM-Alco 251 Engines at Palisades Nuclear Power Plant.Caused by Insufficient Friction Fit Between Pin & Sleeve.Supplier of Pin Will No Longer Be Used ML18068A4921998-10-31031 October 1998 Monthly Operating Rept for Oct 1998 for Palisades Nuclear Plant.With 981103 Ltr ML18068A4851998-10-29029 October 1998 LER 97-011-01:on 971012,starting of Primary Coolant Pump with SG Temps Greater than Cold Leg Temps Occurred.Caused by Inadequate Procedures & Operator Decision.Sop Used for Starting Primary Coolant Pump Enhanced ML18066A3181998-09-30030 September 1998 Monthly Operating Rept for Sept 1998 for Palisades Nuclear Plant ML18066A2901998-08-31031 August 1998 Monthly Operating Rept for Aug 1998 for Palisades Nuclear Power Plant.With 980903 Ltr ML18066A3191998-08-31031 August 1998 Revised Monthly Operating Rept Data for Aug 1998 for Palisades Nuclear Plant ML18066A2831998-08-18018 August 1998 LER 98-010-00:on 980721,reactor Manually Tripped.Caused by Failure of Coupling Which Drives Feedwater Pump Main Lube Oil Pump.Main Lube Oil Pump Coupling & Associated Components Replaced & Satisfactorily Tested ML18066A2771998-08-13013 August 1998 Part 21 Rept Re Deficiency in CE Current Screening Methodology for Determining Limiting Fuel Assembly for Detailed PWR thermal-hydraulic Sa.Evaluations Were Performed for Affected Plants to Determine Effect of Deficiency ML20237E0301998-07-31031 July 1998 ISI Rept 3-3 ML18066A2701998-07-31031 July 1998 Monthly Operating Rept for July 1998 for Palisades Nuclear Plant.W/980803 Ltr ML18066A2311998-06-30030 June 1998 Monthly Operating Rept for June 1998 for Palisades Nuclear Plant ML18066A2261998-06-30030 June 1998 LER 98-009-00:on 980531,small Pinhole Leak Found on One of Welds,During Leak Test Following Replacement of Pcs Sample Isolation Valves.Caused by Welder Error.Leaking Welds Repaired ML18066A3061998-06-18018 June 1998 SG Tube Inservice Insp. ML20249C4951998-06-17017 June 1998 Rev 1 to EA-GEJ-98-01, Palisades Cycle 14 Disposition of Events Review ML18066A1781998-06-0909 June 1998 LER 98-008-00:on 980511,noted That Procedure Did Not Fully Satisfy Requirement to Test High Startup Rate Trip Function. Caused by Misunderstanding of Testing Requirements.Revised TS Surveillance Test Procedure & Reviewed Other Procedures ML18066A1711998-06-0101 June 1998 Part 21 Rept Re Impact of RELAP4 Excessive Variability on Palisades Large Break LOCA ECCS Results.Change in PCT Between Cycle 13 & Cycle 14 Does Not Constitute Significant Change Per 10CFR50.46 ML18066A1741998-05-31031 May 1998 Monthly Operating Rept for May 1998 for Palisades Nuclear Plant.W/980601 Ltr ML18066A2321998-05-31031 May 1998 Revised MOR for May 1998 for Palisades Nuclear Plant ML18068A4701998-05-31031 May 1998 Annual Rept of Changes in ECCS Models Per 10CFR50.46. ML18065B2451998-05-13013 May 1998 LER 98-007-00:on 980413,HPIS Sys Was Noted Inoperable During TS Surveillance Test.Caused by Performance of Flawed Procedure.Operators & Engineers Will Be Trained to Improve Operational Decision Making Through Resources & Knowledge ML18066A2331998-04-30030 April 1998 Revised MOR for Apr 1998 for Palisades Nuclear Plant ML18068A3461998-04-30030 April 1998 Monthly Operating Rept for Apr 1998 for Palisades Nuclear Plant.W/980501 Ltr ML18066A3411998-04-22022 April 1998 Rev 0 to EMF-98-013, Palisades Cycle 14:Disposition & Analysis of SRP Chapter 15 Events. ML18065B2071998-03-31031 March 1998 Monthly Operating Rept for Mar 1998 for Palisades Nuclear Plant.W/980403 Ltr ML20217C2741998-03-31031 March 1998 Independent Review - Is Consumers Energy Method (W Method) of Determining Palisades Nuclear Plant Best Estimate Fluence by Combining Transport Calculation & Dosimetry Measurements Technically Sound & Does It Meet Intent of Pts ML18066A2341998-03-31031 March 1998 Revised MOR for Mar 1998 for Palisades Nuclear Plant ML18068A3041998-02-28028 February 1998 Monthly Operating Rept for Feb 1998 for Palisades Nuclear Plant.W/980302 Ltr ML18066A2351998-02-28028 February 1998 Revised MOR for Feb 1998 for Palisades Nuclear Plant ML18065B1641998-02-0505 February 1998 Rev 0 to Regression Analysis for Containment Prestressing Sys at 25th Year Surveillance. ML18067A8211998-01-31031 January 1998 Monthly Operating Rept for Jan 1998 for Palisades Nuclear Plant.W/980203 Ltr 1999-09-30
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U General Off6ces: 212 West Michegan Avenue, Jackson Michsgen 49201. Area Code St? 7en.OSSO January 14, 1972 Dr. Peter A. Morris, Director Re: Docket 50-255 Division of Reactor Licensing License No DPR-20 United States Atomic Energy Commission Washington, DC 20545
Dear Dr. Morris:
This letter is written to apprise you of a failure of a two-inch, motor-operated valve on the high-pressure safety injection (HPSI) system at the Palisades Plant.
~
On January 5, 1972, the time the difficulty was detected, the plant was in a cold shutdown condition. Maintenance activities were being completed so that plant heatup could begin later the same day. These maintenance activities included the repair of a flow transmitter for a flow indicator (FI-0313) that is common to the discharge of HPGI valve CV-3013 and its redundant HPSI valve CV-3062. After completion of this repair to the flow transmitter, tests were performed on this portion of the HPSI system, following an approved test procedure. When CV-3013 was opened, no flow indication was received. The redundant injection valve (CV-3062) was opened and the flow indicator worked proper 4 To verify proper valve lineup to the HPSI header, another valve was opened and its flow indicator indicated flow. It was concluded that HPSI valve CV-3013 was inoperable and plans for heatup of the primary system postponed until tne cause of the problem with the valve could be determined and the valve repaired.
Preliminary investigations revealed that the motor operator for the valve was operating normally. In addition, the valve stem travel in-dicated that the valve was opening and closing normally. Radiographs were taken of the valve in the open position. These radiographs revealed that the valve plug (disc) had broken. It appeared that the lower portion of the plug was in the valve body seat and the upper portion was attached to the stem.
The valve was disassembled. Removal of the stem confirmed that the upper portion of the plug was attached to the stem while the lower portion of.the plug remained in the seat in the valve body. A small hole i
. 8306290171 720201 _
1 l PDR ADOCK 05000255 P PDR
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., _ Dr. Peter A. Morris -
Dock 3t 50-255 Od 2 January 14, 1972 was drilled in the valve body below the valve seat. A small rod was inserted through the hole such that the remaining portion of the plug could be pushed out the top of the valve body. The plug came out easily.
The valve is a two-inch, motor-operated, bonnet 1cas globe valve.
The valve body material is stainless steel, Grade F-316. The valve plug is made.from a Stellite 6B casting. The plug has a "T"-shaped slot at the top which slips over the end of the valve stem so that it can be with-drawn by the stem when opening the valve. There are two cylindrical guiding surfaces, one at the top of the plug and the second near the middle of the valve just above the seating surface. The middle guide tapers at about 45 degrees to a smaller diameter above the seating sur-face. Below the seating surface, the plug is hollow. The outer surface of the hollowed portion of the plug is tapered slightly and has four narrow axial slots for now throttling purposes.
Examination of the removed valve plug revealed that the valve failed after closing on an object which hid become trapped between the taper of the valve plug's lower guide (above the plug seating surface) and the valve body. This object was wedged under the plug's guiding sur-face at the end of the "T"-shaped slot. The valve closing force was thus concentrated in a small area of the brittle Stellite material which was unsupported from above because it was beneath the open end of the "T" slot. The result was the cracking of the plug at the junction of the h5-degree bevel of the lower guide and the plug surface above the seating surface. Eventually there was some spalling of plug msterial from the lower guide at the botton surface of the slot above. It was concluded from the impression on the plug that the object that caused the initial crackingwassmall,probablyabout1/8-inchindiameter. As about three quarters of the fracture surface area of the cracked plug had accumulated a red oxide deposition, it was concluded that the initial damage had been present for some time, probably since pre-core loading hot-functional testing or flushing operations. The valve appeared to have operated a number of times in this condition. Ultimately, scue object (probably pieces spalled from the plug) became trapped between the seating surfaces of the valve, causing tension and bending forces again to be applied to the valve plug. At this closing cycle or the next opening cycle, the remainder of the material cracked. About one fourth of the surface area of the crack appeared very fresh (no red oxide deposition).
Several small pieces of spalled material from the valve plug were found in the valve body. Marks were found on both the valve plug seating surface and the valve body seating surface. These pieces of material were removed.
The hole that had been drilled through the bottom of the valve body was repaired by tapping the valve body and inserting a threaded plug of stainlest steel 316 material in the hole.. This threaded plug was i seal-weldedI,and the seal weld was dye-penetrant tested. This repair 1 was approved by the valve. manufacturer's design engineer. (Check valves a
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[ 'Dr. Peter A. Morris F Docket 50-255 \
3 January lis,1972 used at the Palisades Plant in a similar service have a seal-welded threaded plug inserted in the lower portion of the valve body in an identical manner. The lower portion of the check valve bodies are identical to the lower body of this two-inch HPSI valve.)
The new valve plug (disc) was radiographed prior to its in-sta11ation. No defects were present in this plug. The remaining three identical two-inch HPSI valves and the four identical redundant HPSI valves were radiographed as assembled. No defects were detected. In
- addition, all eight HPSI valves were test-operated and it was verified '
i that flow was established through each of these eight valves.
It was concluded from the differences in deposition of red oxide material on the fracture surface of the plug that the initial failure had occurred sometime ago, most likely during the pre-core ,
loading hot-functional testing or flushing operations. The foreign ,
object was probably either removed from the system during the reactor vessel cleanout prior to core loading or has settled into area piping where flow is very low. From the impression on the lower guide of the valve plug, we have cencluded that this object must have been very small, probablyabout1/8-inchdiameter. In addition, the valve configuration ;
precludes any object of greater size than about 1/4-inch diameter and 1-1/2 inches long from passing through the valve.
r The valve plug was reconstructed to insure that all of the i spalled material was accounted for. This reccnstruction revealed that several very small chips of the valve plug were missing. These pieces were sufficiently small and light so that there are no concerns about cladding wear if they did reach the reactor vessel.
There is no danger of this foreign material reaching the con- ;
trol rod drive mechanisms. The control rod drive mechanisms are mounted vertically on top of the reactor vessel head; therefore, this material will not settle into them. A moderately strong flow would be required to move this material; no such flow exists through the control rod drive "
mechanisms. In addition, these chips are sufficiently small such that
- they probably would not cause a malfunction of a control rod drive mecha-
- nism even if they were to get into this mechanism.
The effects of plant operation with a similar valve failure have been considered. Sufficient flow indication is available to detect '
a failure of this nature in the HPSI system. Plant procedures require the operators to verify flow conditions if the HPSI system is actuated.
In the event of failure to attain flow through one of these valves, the e
operator can initiate flow throu6h the redundant HPSI system.
To insure that the plant is not operated with an unknown failure 4
existing in one of these valves, a testing program has been established.
This testing progra,m consists of:
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Dr. Pet:r A. Morris pd Docket 50-255 4
January 14, 1972 ;
(1) Prior to plant start-up fra a cold shutdown condition, HPSI system valves CV-3007, -3009, -3011 and -3013 and redundant HPSI system valves CV-3062, -3064, -3066 and
-3068 will be test-operated. Flow through these valves will be established and verified.
(2) The same testing as in (1) above will be conducted on a monthly basis during plant operation.
If these tests reveal a failure of an HPSI valve, the appro- i priate technical specification limits will be 'followed.
From our review of this valve failure, we have concluded that this incident does not involve an unreviewed item with regard to reactor ,
plant safety considerations. The cause of 'the failure of this valve has been determined and the valve has been repaired. In the unlikely event that a similar failure were to recur, a testing program has been estab- i lished that will insure prompt detection of a valve failure.
Yours very truly, RalphB.Sewell(Signed)
RBS/ map Ralph B. Sewell Nuclear Licensing Administrator CC: Boyce H. Grier USAEC i
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