Containment Tendon Deficiency Interim Rept.Describes Insp & Tests of pre-stressing Tendon Button Heads That Developed Unusually High Number of Defects.Final Rept Containing Evaluation of Test Will Be SubmittedML19259A717 |
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LaSalle |
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01/04/1979 |
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COMMONWEALTH EDISON CO. |
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ML19259A715 |
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NUDOCS 7901100184 |
Download: ML19259A717 (3) |
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Category:DEFICIENCY REPORTS (PER 10CFR50.55E & PART 21)
MONTHYEARML20217A1691999-09-22022 September 1999 Part 21 Rept Re Engine Sys,Inc Controllers,Manufactured Between Dec 1997 & May 1999,that May Have Questionable Soldering Workmanship.Caused by Inadequate Personnel Training.Sent Rept to All Nuclear Customers ML20153D0191998-09-18018 September 1998 Part 21 Rept Re Defect in Gap Conductance Analyses for co- Resident BWR Fuel.Initially Reported on 980917.Corrective Analyses Performed Demonstrating That Current Operating Limits Bounding from BOC to Cycle Exposure of 8 Gwd/Mtu ML20153C6771998-09-17017 September 1998 Part 21 Rept Re Defect Relative to MCPR Operating Limits as Impacted by Gap Conductance of co-resident BWR Fuel at Facilities.Operating Limit for LaSalle Unit 2 & Quad Cities Unit 2 Will Be Revised as Listed ML20236N6751998-07-0909 July 1998 Part 21 & Deficiency Rept Re Notification of Potential Safety Hazard from Breakage of Cast Iron Suction Heads in Apkd Type Pumps.Caused by Migration of Suction Head Journal Sleeve Along Lower End of Pump Shaft.Will Inspect Pumps ML20198K5081998-01-0606 January 1998 Part 21 Rept Re Transient Analyses at Exposures Prior to End of Cycle.Caused by Component Defect.Notified Commonwealth Edison of Defect & Provided Revised Limits by Siemens Power Corp ML20203B3691997-12-10010 December 1997 Part 21 Rept Re Potential to Exceed Operating Limits.Cycle 8 Delayed Until Fall 1998 ML20134Q0801996-11-27027 November 1996 Part 21 Rept Re Deficiency of Wkm Model 70-13 Pneumatic Actuators Manufactured by Anchor Darling Valve Company Due to Incorrect Calculation of Bench Set & Supply Air Set Points.All Affected Valves Have Been Reviewed & Evaluated ML20128F5011996-10-0404 October 1996 Part 21 Rept & Deficiency Rept Re Wkm Model 70-13 Pneumatic Actuators Mfg by Anchor Darling Valve Co.All Affected Valves Being Reviewed/Evaluated & Design Changes Are Being Initiated as Required ML20117P3141996-09-11011 September 1996 Part 21 Rept Re Deficiency of GE Type RMS-9 Overcurrent Trip Device Programmers ML20082B5271995-03-28028 March 1995 Part 21 Rept Re Notification 9505 Automatic Switch Co Pilot Solenoid Valve Model NP8323A20V.Caused by Failures of MSIVs to Close to Asco Pilot Solenoid Valves.Subj Valves Replaced W/Valcor 3-way Solenoid Valves ML20082E1901995-03-27027 March 1995 Part 21 Rept Re Sticking of B Core Assembly to Plugnut on Automatic Switch Co Dual Solenoid Valve Model NP8323A20V. Unit 2 Valves Replaced.Unit 1 Valves Will Be Replaced ML20069A8631994-05-17017 May 1994 Final Part 21 Rept Re Secondary Containment Isolation Techno Corp Dampers Equipped W/Parker Hannifin Air Cylinders at LaSalle County Station.All Units 1 & 2 Techno Dampers Equipped W/Parker Air Cylinders Replaced ML20070N3451994-05-0202 May 1994 Part 21 Rept Re Failures of Limit Switch Series EA740-86700 Mfg by Namco Controls Co Due to Excessive Amount of Grease on Contact Block & Contact Carrier & Wrong Matl of O-ring. Series EA740-86700 Switches Replaced w/EA740-50100 Switches ML20063D0861994-02-0202 February 1994 Part 21 Rept Re Possible Anomaly W/Namco Controls EA740 & EA750 Series Limit Switches.Investigation in Progress & Has Not Been Concluded.Vendor Will Advise NRC within Next Thirty Days Re Matter as Addl Info Becomes Available ML20059L9861993-11-11011 November 1993 Part 21 Rept Re Deviation Wherein Fully Open Butterfly Valve Located 15 Pipe Diameters Upstream of Sensors Was Disturbing Flow Profile Enough to Cause Ultrasonic Meter to Indicate 3 to 4% Low.Customers Notified & Valve Removed ML20043A6091990-04-27027 April 1990 Part 21 Rept Re Defective Axial Cracks in Pump Shaft in Region Immediately Above Impeller & in Reactor Recirculation Pumps.Probably Caused by Crack Growth as Thermal Fatigue. Technical Advisory Bulletin Will Be Sent to Each Util ML20211P7211987-02-23023 February 1987 Part 21 Rept Re Rockbestos Coaxial Cable Used in Sorrento Electronics Digital & Analog high-range Radiation Monitor. Insulation Resistance at High Temp Not High Enough for Ion Chamber & Associated Electronics to Operate Properly ML20207J8491986-07-25025 July 1986 Part 21 Rept Re Potential Change in Allowable Operating Repeatability Ranges for 1E Qualified Series 9,8 & 1 Pressure Switches.Licensee Calibr Procedures Should Be Amended to Allow for Cycling (Hysteresis) Effects ML20198R5751986-06-0303 June 1986 Part 21 Rept Re Failure of 103/B212 Type Differential Pressure Switches to Give Scram During 860601 Feedwater Transient.Investigation Continuing ML20140A5281985-12-19019 December 1985 Part 21 Rept Forwarding Ltr Sent to Customers Re Check Valves Missing Lock Welds on Hinge Supports or Hinge Support Capscrews,Per 851121 Request.List of Customers Receiving Ltr Also Encl ML20128G5101985-05-24024 May 1985 Part 21 Rept Re Heat Numbers to Be Added & Deleted from Sublist Sheet A,Based on Review of NRC ML20127N0621985-05-13013 May 1985 Part 21 Rept Re Incorrect Short Time Delay Band Lever Inadequately Installed in Low Voltage K-line Circuit Breaker Electromechanical Overcurrent Trip Device.Visual Insp to Determine If Correct Lever Installed Recommended ML20099F3921984-11-0808 November 1984 Part 21 Rept Re Hexcel/Mci Pipe Restraints Found W/Average Dynamic Crush Strength Values Below Acceptable Values. Initially Reported on 841101.Replacement Program in Progress ML20096A5441984-08-21021 August 1984 Part 21 Rept Re Ground Fault Failures of Actuation Solenoids for Crosby Safety Relief Valves PRC 84-24.Problem Still Considered Germane Condition.Memo of 840808 Telcon Updating 840615 Interim Rept Encl ML20083J7731983-12-22022 December 1983 Final Deficiency Rept Re Defective GE Hma Relays.Initially Reported on 830805.Two Relays Found to Have Insufficient Armature Clearance.Adjustments Made ML20082Q6921983-12-0202 December 1983 Final Deficiency Rept 83-07 Re Design Calculation for Fire Water Sys.Initially Reported on 831102.Preliminary Calculations Completed.Final Rept Will Be Submitted Approx 20 Days Prior to Exceeding 5% Power ML20085K6361983-10-12012 October 1983 Final Deficiency Rept 83-06 Re Asco Solenoid Valves in Control Rod Drive Sys.Initially Reported on 830912.Valves W/Defective Solenoid Plunger Housings Replaced & Spare Parts in Inventory Examined.Plant Operable ML20077N6151983-09-0101 September 1983 Interim Deficiency Rept 83-05 Re Potentially Defective GE Hma Relays Mfg in 1974.Initially Reported on 830805.Two Relays Found W/Insufficient Armature Clearance.Clearance Adjusted.Final Rept Expected by 830923 ML20076A8221983-08-0808 August 1983 Corrects Final Deficiency Rept 83-01 Re Riley Temp Indicating Switches.Riley Temp Switches Not Recalibr to Modified Calibr Procedure.Calibr to Be Done Prior to Fuel Load ML20077A8961983-07-15015 July 1983 Final Rept Re Potentially Defective Figures 425,426 & 428 Spring Hangers Mfg by Elcen Metal Products Co.Initially Reported on 830617.Review Revealed Spring Hanger Installed at Facility Not Type in Question.Item Closed ML20024B7771983-07-0707 July 1983 Final Deficiency Rept 83-03 Re Medium Voltage Circuit Breakers of Same Type Installed at Limerick Which Inadvertently Closed After Completion of Spring Charging Due to Slipped Close Latch,Discussed in Brown Boveri 830524 Ltr ML20072A7371983-06-0303 June 1983 Final Deficiency Rept Re Problems W/Riley Temp Switches. Initially Reported on 830316.Based on Engineering Evaluation by Riley,Switches Accurately Perform Intended Function When Calibr W/Modified Procedure ML20083L9751983-05-27027 May 1983 Part 21 Rept Re Failure of Circuit Breakers During Environ Testing.Test Results Indicate That Temp Sensitivity Problem May Be Generic to All Ite Imperial Corp thermal-magnetic Circuit Breakers Calibr for 40 C Svc ML20074A3101983-05-0404 May 1983 Part 21 Rept Re Defect in Shielded Multiconductor Cable Installed in HVAC Control Panels.Mcc Powers Personnel Attached Hold Tags to 13 HVAC Control Panels W/Defect. Evaluation Being Conducted ML20073T1421983-05-0303 May 1983 Updated Interim Deficiency Rept Re Offset & Module Problems of Riley Temp Indicating Switches in Leak Detection Sys. Calibr Procedure Modified.Final Resolution of Module Problem (Hardware Mod) in Progress.Final Rept Expected by 830601 ML20073S6731983-05-0202 May 1983 Interim Deficiency Rept 83-01 Re Temp Offset Problems Experienced W/Riley Temp Switches Installed in Leak Detection Sys.Calibr Procedure Modified & Switches Recalibr. Final Rept Will Be Submitted by 830601 ML20024B7841983-04-28028 April 1983 Followup Interim Rept Re Potential Deficiency in 5HK Switchgear Supplied by Brown Boveri.Circuit Breaker Inadvertently Closed & Tripped Following Spring Charging. Light Spring Added to Close Latch ML20074A2041983-04-26026 April 1983 Interim Deficiency Rept Re Misapplication of Ite Gould Circuit Breakers in post-LOCA Hydrogen Recombiners Supplied by Rockwell Intl.Initially Reported on 830328.Matter Under Investigation.Final Rept by 830808.Reported Per Part 21 ML20074A3191983-04-18018 April 1983 Part 21 Rept Re Defect in Shielded Multiconductor Cable Installed in HVAC Control Panels.All Suspect Panels Inspected & Nonconformance Rept Will Be Issued for Applicable Sites ML20073F6751983-04-0707 April 1983 Final Const Deficiency Rept 82-07 Re Shop Welding by Unauthorized Welders.Zack Co Officially Withdrew Part 21 Rept on 820914 Based on Results of Investigation ML20072P7311983-03-30030 March 1983 Revised Final Deficiency Rept 81-06 Re Crosby Safety Relief Valve IMF-2 Solenoid Valve.Solenoids Have Had Qualified Collet/Yoke Assembly Installed,Closing Out Undervoltage Concern.Valves Qualified Per NUREG-0588 ML20069E4501983-03-16016 March 1983 Final Deficiency Rept Re Significant Deviation from Performance Specs for Sor,Inc Pressure Switches Installed as Part of ECCS Interlock Mod.Initially Reported on 830216. All Leaking O-rings Replaced ML20069E6671983-03-16016 March 1983 Interim Deficiency Rept 83-01 Re Significant Deviation from Performance Specs for Riley Temp Switches in Leak Detection Sys.Initially Reported on 830215.Two Units Returned to GE for Evaluation.Temp Module Resolution Expected by Apr 1983 ML20074A2221983-03-11011 March 1983 Part 21 Rept Re Failure of post-LOCA Hydrogen Recombiner Component During IEEE-323 Qualification Program.Circuit Breaker Not Properly Selected for Specific Application.Plant Operators Notified of Deviation ML20071E9191983-03-0101 March 1983 Final Deficiency Rept 82-08 Re Electrical Penetration Assemblies.Initially Reported on 820817.Replacement Modules Will Be Installed by 830501 ML20070R8521983-01-24024 January 1983 Interim Deficiency Rept 82-08 Re Electrical Penetration Assembly Butt Splices.Replacement Modules for Awg Cable Modules 2 & 6 Ordered from Conax.Final Rept Will Be Provided on or About 830303 ML20028E6511983-01-21021 January 1983 Final Deficiency Repts 82-10 & 11 Re Rigid Strut Pins Mfg by Elcen.Initially Reported on 821223.Test Results Indicate No Load Capacity Data Values Violated.If Such Pins Were Used,Design Margins Not Exceeded ML20073J5211982-12-14014 December 1982 Part 21 Rept Re Likely Failure of post-LOCA Hydrogen Recombiner Component,Dpst Toggle Switch 12TSI-2 Due to Aging & Radiation.Field Bulletins Issued to Install Jumpers Bypassing Switch ML20079J7921982-12-14014 December 1982 Interim Deficiency Rept Re Inadequate Pressure Transducers/ Transmitters Mounted on post-LOCA Hydrogen Recombiners. Initially Reported on 821119.Final Rept Will Be Submitted by 830211.Also Reported Per Part 21 ML20066J5131982-11-18018 November 1982 Final Deficiency Rept Re Overtorqued Anchor Bolts on ECCS Pump Foundation.Initially Reported on 821019.Recheck of Torque Values to Be Performed by 821206.Sargent & Lundy 821110 Evaluation of Anchor Bolt Status Encl 1999-09-22
[Table view] Category:TEXT-SAFETY REPORT
MONTHYEARML20217C9121999-10-12012 October 1999 SER Input Authorizing Licensee Proposed Request to Modify Definition of Core Alteration in Section 1.0 of TS & Update Sections 3/4.1,3.4.3 & 3/4.9 to Reflect Proposed Definition Change ML20217F9091999-09-30030 September 1999 Monthly Operating Repts for Sept 1999 for LaSalle County Stations,Units 1 & 2.With ML20217A1691999-09-22022 September 1999 Part 21 Rept Re Engine Sys,Inc Controllers,Manufactured Between Dec 1997 & May 1999,that May Have Questionable Soldering Workmanship.Caused by Inadequate Personnel Training.Sent Rept to All Nuclear Customers ML20212C4501999-08-31031 August 1999 Monthly Operating Repts for Aug 1999 for LaSalle County Station,Units 1 & 2.With ML20210R0671999-07-31031 July 1999 Monthly Operating Repts for July 1999 for LaSalle County Station,Units 1 & 2.With ML20210C1681999-07-0909 July 1999 Seventh Refueling Outage ASME Section XI Summary Rept ML20209H1501999-06-30030 June 1999 Monthly Operating Repts for June 1999 for LaSalle County Station,Units 1 & 2.With ML20195J7871999-05-31031 May 1999 Monthly Operating Repts for May 1999 for LaSalle County Station,Units 1 & 2.With ML20209E1431999-05-31031 May 1999 Cycle 8 COLR, for May 1999 ML20195B2591999-05-19019 May 1999 Rev 66a to CE-1-A,consisting of Proposed Changes to QAP for Dnps,Qcs,Znps,Lcs,Byron & Braidwood Stations ML20206N2071999-04-30030 April 1999 Monthly Operating Repts for Apr 1999 for LaSalle County Station,Units 1 & 2.With ML20205L8421999-03-31031 March 1999 Rev 2 to EMF-96-125, LaSalle Unit 2 Cycle 8 Reload Analysis ML20205L8301999-03-31031 March 1999 Administrative Technical Requirements App B (Amend 26) LaSalle Unit 2 Cycle 8 COLR & Reload Transient Analysis Results, for Mar 1999 ML20205R2721999-03-31031 March 1999 Monthly Operating Repts for Mar 1999 for LaSalle County Station,Units 1 & 2.With ML20205L8391999-03-22022 March 1999 Rev 2 to 960103, Neutronics Licensing Rept for LaSalle Unit 2,Cycle 8 ML20204C8141999-02-28028 February 1999 Monthly Operating Repts for Feb 1999 for LaSalle County Station,Units 1 & 2.With ML20199E4601998-12-31031 December 1998 Monthly Operating Repts for Dec 1998 for LaSalle County Station,Units 1 & 2.With ML20207C7371998-12-31031 December 1998 Annual Rept for LaSalle County Station for Jan 1998 Through Dec 1998 ML20205M7061998-12-31031 December 1998 Unicom Corp 1998 Summary Annual Rept. with ML20198B3801998-12-14014 December 1998 SER Accepting one-time Request for Relief from Certain Provisions of Section XI of ASME Boiler & Pressure Vessel Code,Per 10CFR50.55a for Certain Plant Safety/Relief Valves ML20206N2261998-12-0909 December 1998 LER 98-S03-00:on 981116,protected Area Was Entered Without Current Authorization for Unescorted Access Due to Programmatic Deficiency Error.Changed Badge Control Process ML20197K0981998-11-30030 November 1998 Monthly Operating Repts for Nov 1998 for LaSalle County Station,Unts 1 & 2.With ML20196B1441998-11-23023 November 1998 Safety Evaluation Accepting Licensee Response to GL 95-07, Pressure Locking & Thermal Bindings of Safety-Related Power-Operated Gate Valves ML20196A4191998-11-19019 November 1998 Safety Evaluation Accepting QA TR CE-1-A,Rev 66 Re Changes in Independent & Onsite Review Organization by Creating NSRB ML20195D3191998-10-31031 October 1998 Monthly Operating Repts for Oct 1998 for LaSalle County Station.With ML20154H6781998-09-30030 September 1998 Monthly Operating Repts for Sept 1998 for LaSalle County Nuclear Power Station,Units 1 & 2 ML20153D0191998-09-18018 September 1998 Part 21 Rept Re Defect in Gap Conductance Analyses for co- Resident BWR Fuel.Initially Reported on 980917.Corrective Analyses Performed Demonstrating That Current Operating Limits Bounding from BOC to Cycle Exposure of 8 Gwd/Mtu ML20153C7621998-09-18018 September 1998 Safety Evaluation Acceping NRC Bulletin 95-002, Unexpected Clogging of RHR Pump Strainer While Operating in Suppression Pool Cooling Mode ML20153C6771998-09-17017 September 1998 Part 21 Rept Re Defect Relative to MCPR Operating Limits as Impacted by Gap Conductance of co-resident BWR Fuel at Facilities.Operating Limit for LaSalle Unit 2 & Quad Cities Unit 2 Will Be Revised as Listed ML20151W0241998-08-31031 August 1998 Monthly Operating Repts for Aug 1998 for LaSalle County Station.With ML20237E2921998-08-21021 August 1998 Special Rept:On 980811,channel 5 of Lpms Became Inoperable. Caused by Channel Failed pre-amplifier Located Inside Primary Containment at Inboard Side of Electrical Penetration E-19.Initiated Repairs of Channel ML20237E2331998-08-21021 August 1998 Revised Pages of Section 20 of Rev 66 to CE-1-A, QA Topical Rept ML20237B4861998-07-31031 July 1998 Monthly Operating Repts for July 1998 for LaSalle County Nuclear Power Station Units 1 & 2 ML20236V7701998-07-31031 July 1998 Revised LaSalle Unit 1 Cycle 8 COLR & Reload Transient Analysis Results ML20236P8231998-07-14014 July 1998 Special Rept:From 980614-17,various Fire Rated Assemblies Were Inoperable for Period Greater than Seven Days.Caused by Test Equipment Being Routed Through Fire Doors.Established Fire Watches & on 980619 Assemblies Were Declared Operable ML20236N6751998-07-0909 July 1998 Part 21 & Deficiency Rept Re Notification of Potential Safety Hazard from Breakage of Cast Iron Suction Heads in Apkd Type Pumps.Caused by Migration of Suction Head Journal Sleeve Along Lower End of Pump Shaft.Will Inspect Pumps ML20236L8041998-07-0606 July 1998 Safety Evaluation Granting Licensee 980304 Request for Second 10-yr Interval Pump & Valve IST Program Plan,Rev 2, Including Changes to 2 ASME Boiler & Pressure Vessel Code Relief Requests Previously Submitted in Rev 1 ML20236P3611998-06-30030 June 1998 Monthly Operating Repts for June 1998 for LaSalle County Nuclear Power Station,Units 1 & 2 ML20249C4891998-06-22022 June 1998 Special Rept:On 980522,Fire Detection Zone 1-31 Was Noted out-of-service for More than 14 Days.Detection Sys Was Taken out-of-service on 980508 to Prevent False Alarms During Hot Work Activities.Sys Was Returned to Operable Status 980528 ML20248M3101998-05-31031 May 1998 Monthly Operating Repts for May 1998 for LaSalle County Nuclear Power Station,Units 1 & 2 ML20236V7771998-05-31031 May 1998 Rev 1 to 24A5180, Supplemental Reload Licensing Rept for LaSalle County Station Unit 1 Reload 7 Cycle 8 ML20217Q7041998-05-0404 May 1998 Safety Evaluation Accepting Util Request to Leave Leak Chase Channels Plugged During Performance of Containment ILRT ML20247M4491998-04-30030 April 1998 Monthly Operating Repts for Apr 1998 for LaSalle County Station ML20216F4941998-03-31031 March 1998 Monthly Operating Repts for Mar 1998 for LaSalle County Station,Units 1 & 2 ML20217N6581998-03-30030 March 1998 Special Rept on Fire Detection,Deluge Sys & Fire Rated Assemblies During Period of 980303-25.Established Fire Watches Until Affected Equipment Is Returned to Operable Status ML20216D9511998-02-28028 February 1998 Monthly Operating Repts for Feb 1998 for LaSalle County Station,Units 1 & 2 ML20247M4631998-02-28028 February 1998 Rev Monthly Operating Rept for Feb 1998 for LaSalle County Station ML20203D7241998-02-20020 February 1998 Special Rept:On 980118,Fire Detection Zones 1-18 & 2-18 Taken out-of-svc to Prevent False Alarms During Hot Work Activities on Auxiliary Electric Equipment Room Ventilation Sys.Fire Watches Will Remain in Place ML20202G9851998-01-31031 January 1998 Monthly Operating Repts for Jan 1998 for LaSalle County Station,Units 1 & 2 ML20199K1651998-01-23023 January 1998 Rev 65h to Topical Rept CE-1-A, Comm Ed QA Tr 1999-09-30
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Commonwealth Edison' NRC Docket Nos. 50-373/374 f ,
ATTACHMErg
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LASALLE COUNTY UNITS 1 AND 2 INTERIM REPORT CONTAINMENT TENDON DEFICIENCY The tendons that are the subject of this deficiency are used to pre-stress the primary containment. Several hundred tendons run horirontally ar ound the contaimnent at different elevations and vertically up the containment wall. The tendons are tensioned after the concrete containment wall is poured. Each tendon consists of a group of ninety (90) , 0.250" diameter wires made from high strength steel (A421 Grade BA) with a minimum tensile strength of 240,000 psi. At each end, the tendon emerges from its guide tube, ordbedded in the concrete wall, and passes through a moveable anchor head with 90 holen in it -- one for each wire. Each wirc end is upset, forming a button head that will not pass back through the anchor head. The anchor head is then hydraulically tensioned to about 740,000 pounds and shimmed in place against a steel bearing plate. One end of each wire is upset in the shop to form the button head while the other end is upset in the field after the tendon is pulled into its tube and the anchor head is installed.
Often, when the wire end is being upset, either at the shop or in the field, the button head will develop defects of several types. Because of this, after upsetting, the button heads are inspected to Inland Ryerson (the tendon supplier)
Specification 1610 which describes the defects and their acceptance criteria. The upset wires undergo a 100% visual in-spection for cracks at the shop and in the field, and a minimum 10% examination for size of flaw with a go-no-go gauge.
Walsh Construction Company, the LaSalle structural contractor and tendon installer, was experiencing an unusually high number of button head rejections when upsetting the Unit 2 vertical tendons. As a result, Walsh also inspected the shop-installed button heads on the problem tendons on which rejectable button heads had been identified.
Field Innpection The upper (shop) ends of 7 tendons, containing a total of G30 wires, were inspected. The si7e of the defect openings was measured optically with a small 7X Bausch.and Lomb measuring magnifier. The scale had divisions every 0.005", thus the accuracy of any single measurement is estimated to be IO.0025."
790110018)
Commonwealth Edison NRC Docket Nos. 50-373/374 r
Of t'hc 6'0 3 tendons inspected, 27 were rejectable, 30 more were borderline caaen. Subscauent inspection of the borderline cases with feeler gauges identified additional nonconforming wire.
Laboratorv Studies Following the field inspection, several button heads that had been rejected and cut off were studied in the laboratory.
A piece of wire was mounted and polished and microscopically examined for inclusions or other microstructural defects. The steel was not unusually dirty and appeared to be normal. Another button head with a large split was cooled in liquid nitrogen and impacted sharply to break it open. The fracture surfaces, which included the surfaces of the previously existing split were examined for inclusions using energy dispersive x-ray analysis in the scanning electron microscope. A few scattered particles of an aluminium and iron compound, possibly and oxide, were found on the fracture surface and appeared to be embedded in the material.
This is not unusual as the particles could have been either contamination or the result of aluminum killing of the steel.
In any case, they were not judged to be detrimental or the cause of the large splits.
Hardness of the wire was in the range 40-44 RC.
Discussion The tendon button head deficiencies identified at the
" shop end" of seven (7) LaSalle Unit 2 tendons are considered to be the result of the fabricator's shop inspection procedure where the inspection of finishem button head was done after the ends had been greased. This fact and locally inadequate lighting in sections of the inspection area resulted in the failure to identify the nonconformance condition. At issue in the apparent breakdown in the OA/OC program of the tendon supplier and not a concern over the safety and strength of button heads with defects larger than presently permissiblo. It is judged that flaws of the type and number observed do not affect the integrity of the installed tendons. This judgement is based upon preliminary tests performed by the tendon fabricator (Inland-Ryerson) in which wire samples with grass button head flaws were shown to have tensile strengths in excess of the minimum required (240,000 psi) .
Commonwealth Edison NRC Docket Nos. 50-373/374 r
In order to support this judgement for the different heats of material used on LaSalle Units 1 and 2, and other units for which tendons were supplied by the same fabricator, a test
. program has been undertaken. This program will include:
( i) 200 single wire tensile tests
( ii) a full 90 wire tendon low-cycle dynamic test and subsequent tensile test (iii) a full 170 wire tendon low-cycle dynamic test and subsequent tensile test
( iv) a 30 wire tendon high-cycle dynamic test The various wires to be tested will cover numerous heats of material with tensile strengths including the minimum strength of wire employed at LaSalle County. The button heads will contain flaws, some grossly in excess of the current button head acceptance criteria.
This test program which is designed to provide a formal basis for a revised button head acceptance criteria, is expected to be concluded and the results evaluated by Commonwealth Edison in the first quarter of 1979. A final report to complete the reporting requirements of 10 CFR 50.55 (e) will be submitted to Region III by April 15, 1979. Although it is judged that no remedial action is required on tendonc installed at the LaSalle site, the final report to be submitted will identify any corrective action required.
The vendor nonconformance report that documents the deficiencies observed on LaSalle Unit 2 is on file at the plant site for review (Inland Ryerson Report NC/CA No. 676-19). A complete report on the wire test program results and wire inspection results on both LaSalle Units 1 and 2 shall be submitted by April 15, 1979 as a part of the final report.