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Category:REPORTABLE OCCURRENCE REPORT (SEE ALSO AO LER)
MONTHYEARML20202F9161998-01-29029 January 1998 Special Rept:On 980128,two of Three Fire Protection Pumps Were Removed from Svc as Result of Sys Configuration Necessary to Support Planned Maintenance.Fire Pumps Were Returned to Svc on 980128 ML20138F5801997-04-29029 April 1997 Special Rept:On 970402,declared Reactor Bldg Wide Range Gas Monitor Inoperable.Caused by Ruptured Pump Diaphragm. Initiated Work Order,Installed Replacement Pump & Declared Pump Operable ML20137Y2171997-04-15015 April 1997 Special Rept:On 961220,util Rail Car Was Released to Burlington Northern Railroad from Monticello Nuclear Plant. Rail Car Was Delayed in Chicago as Result of Problems W/Bill of Lading on Computer Sys.Rail Car Was Delivered on 970131 ML20101E8321996-03-15015 March 1996 Special Rept:On 960314,two of Three Fire Pumps Removed from Svc for Planned Mod Work.Returned Both Fire Pumps to Svc Same Day ML20094E4371995-10-31031 October 1995 Special Rept:On 951010,sys Engineer & Technicians Reintiated Work on B Channel of Reactor Bldg Vent Radiation Monitor, After Providing Proper Notification to Main Control Room. Caused by Incorrect Channels Removed from Svc ML20082R6601995-04-19019 April 1995 Special Rept:On 950404,discovered That Manual Isolation Valves for 'A' Channel in Closed Position.Cause of Failure to Correctly Position Valves Will Be Assessed.Valves Placed in Required Position & Demonstrated Operability ML20082E5661995-04-0606 April 1995 Special Rept:On 950326,pump Discharge Relief Valve for Electric Screen Wash/Fire Pump Became Inoperable.Valve Had to Be Secured to Permit Installation of an Isolation Device. Pump Returned to Operational Status After Device Installed ML20080G4731995-02-0101 February 1995 Special Rept:On 950119,two of Three Fire Protection Pumps Out of Svc for Period of Approx 15 H.Action Taken for Planned Preventative Maint on Two Check Valves & Drain Valve in Fire Suppression Sys.Roving Fire Watch Established ML20067D1351994-02-23023 February 1994 Special Rept:On 940126,fire Door 105 Declared Inoperable Due to Inability to Close Properly.Caused by Higher than Normal Differential Pressure Between Plant Administration Bldg & Turbine Bldg.Cause of Failure Corrected ML20117A5801992-11-24024 November 1992 Special Rept:On 921020,determined That RHR Sample Supply Loops a & B Excess Flow Check Valves Not Included in ASME Section XI Program.Caused by Lack of Proven Test Procedure. Valves Incorporated Into Third 10-yr ASME Program ML20082G9261991-08-15015 August 1991 Special Rept:On 910719,potential for Inoperable Penetration Fire Barrier Identified.Caused by Use of Less Conservative, But Technically Acceptable,Design Alternatives in Plant Const.Vents Will Be Rerouted ML20244E5941989-06-16016 June 1989 Special Rept:On 890603,two Out of Three Diesel Fire Pumps Were Inoperable for Less than 12 H.Caused by Diesel Fire Pump Day Tank Outlet Valve Being Closed Instead of Fill Valve During Performance Test 1158.Test Revised BECO-86-173, Partially Withheld Security Event Rept:On 861107,HVAC Duct, Penetrating Vital Area,Removed by Contracted Craft Workers Before Notifying Security.Cause Not Stated.Security Oversight of Subj Contract Work Intensified1986-11-12012 November 1986 Partially Withheld Security Event Rept:On 861107,HVAC Duct, Penetrating Vital Area,Removed by Contracted Craft Workers Before Notifying Security.Cause Not Stated.Security Oversight of Subj Contract Work Intensified BECO-86-171, Partially Withheld Security Event Rept:On 861106,temporary Vital Area Barrier Insp Found Barrier Could Be Breached. Barrier Modified & Compensatory Security Measures Released1986-11-10010 November 1986 Partially Withheld Security Event Rept:On 861106,temporary Vital Area Barrier Insp Found Barrier Could Be Breached. Barrier Modified & Compensatory Security Measures Released ML20211E0731986-09-26026 September 1986 Unplanned Operating Event Rept 85-6, Manual Reactor Trip Following MSIV Closure Due to Inadvertent Emergency Feedwater Actuation,851009 BECO-86-125, Partially Withheld Security Event Rept:On 860826,bomb Threat Received.Search Initiated.No Suspicious Objects Found1986-08-29029 August 1986 Partially Withheld Security Event Rept:On 860826,bomb Threat Received.Search Initiated.No Suspicious Objects Found ML20238E4601986-08-28028 August 1986 Partially Withheld Secrity Event Rept:On 860824,bomb Threat Received for Plants.Bomb Search Initiated.No Suspicious Objects Found ML20211K8211986-06-18018 June 1986 Special Rept:On 860521,valid Failure Occurred on Div 2 Diesel Generator During Performance of Tech Spec Surveillance 4.8.1.1.2.Caused by Failure of Jacket Water Thermostatic Control Valve to Open ML20238E4591986-06-17017 June 1986 Partially Withheld Security Event Rept:On 860612,withheld Discovery Made Re 860604 Moderate Loss of Security Effectiveness.Caused by Inadequate Post Orders & Training for Assignment.Assignments Will Be Specifically Addressed 05000000/LER-1986-009, Ro:On 860312,discovered That LER 2-86-04 & LER 86-009 Not Submitted to Nrc.Caused by Misplaced Repts.Repts Telecopied to Nrc.Procedure for Distribution of Repts Revised1986-04-14014 April 1986 Ro:On 860312,discovered That LER 2-86-04 & LER 86-009 Not Submitted to Nrc.Caused by Misplaced Repts.Repts Telecopied to Nrc.Procedure for Distribution of Repts Revised BECO-86-016, Partially Withheld Security Event Rept:On 860215 Security Officer Appeared to Be Asleep at Post at Vital Area Penetration.Unathorized Entry of Vital Area Did Not Occurr. Security Officer Relieved of Duty & Suspended1986-02-20020 February 1986 Partially Withheld Security Event Rept:On 860215 Security Officer Appeared to Be Asleep at Post at Vital Area Penetration.Unathorized Entry of Vital Area Did Not Occurr. Security Officer Relieved of Duty & Suspended BECO-85-220, Partially Withheld Security Event Rept:On 851204 Vertical Pipe Chase Not Locked.Lock Removed When Surveys Indicated Radiation Level Below Requirement for Locked High Radiation Level.Pipe Chase Will Be Secured1985-12-0909 December 1985 Partially Withheld Security Event Rept:On 851204 Vertical Pipe Chase Not Locked.Lock Removed When Surveys Indicated Radiation Level Below Requirement for Locked High Radiation Level.Pipe Chase Will Be Secured AECM-84-0204, Special Rept 84-017/0:on 840304,Fire Doors 1A401 & OC219 Blocked Open to Support Maint Activities.Fire Watches Established Until Doors Restored1984-04-0606 April 1984 Special Rept 84-017/0:on 840304,Fire Doors 1A401 & OC219 Blocked Open to Support Maint Activities.Fire Watches Established Until Doors Restored ML20198H3691983-11-14014 November 1983 Ro:On 831003,results of as-found Tests Indicated Crosby Main Steam Relief Valves Had Lift Points Exceeding Tech Spec Limits.Valves Disassembled & Rebuilt by Mfg ML20081G9561983-10-25025 October 1983 Ro:On 831024,trip Coil for Reactor Recirculation Motor Generator Set 11 Drive Breaker Failed to Trip Automatically. Investigation Ongoing.Trip Coil Replaced ML20105D2431983-06-24024 June 1983 Special Rept:Five Individuals Found to Have Received Radiation in Excess of 10CFR20.101 Limits W/O Required Documentation.Caused by computer-based Sys Feature Allowing Use of Outdated Info & Personnel Error.Procedures Revised ML20066E0131982-11-0101 November 1982 Ro:On 821031,thru Wall Defect Found on C 12-inch Recirculation safe-end to Pipe Weld Joint.Resolution Under Investigation ML20064E5141982-10-21021 October 1982 Ro:On 821020,thru Wall Defect Found on E 12-inch Recirculation Sys Safe End to Pipe Weld Joint.Indications Will Be Documented as Revision to RO 82-16 Reported on 820928.Resolution Being Investigated ML20064E4761982-10-11011 October 1982 Ro:On 821009,linear Indications Confirmed to Exist on Three Addl Welds in Recirculation Sys.Indications Will Be Documented as Revision to RO 82-16 Reported on 820928. Resolution Being Investigated ML20071N4361982-09-28028 September 1982 Ro:On 820928,crack Indication in End Cap of a Recirculation Riser Confirmed by Radiography.Indications Initially Detected by Ultrasonic Exam During Normal Inservice Insp. Remedial Measures Under Investigation ML20071L8261982-09-16016 September 1982 Ro:On 820915,leak Discovered on Primary Containment Suppression Chamber Nitrogen Control Sys Inboard Isolation Valve (AO-2378).Leakage Less than Tech Spec Allowable Leakage ML20053E8071982-06-0202 June 1982 RO Iii:On 810224,failure of Discharge Valve on Instrument & Svc Air Compressor Resulted in Loss of Instrument Air Sys Pressure Causing Plant Scram.Failed Check Valve Replaced W/Similar Unit ML20137G4501981-03-24024 March 1981 Ro:During walk-through of Operator Training Program, O-ring Seal of Filter Holder Found Not Seated Properly Causing Partial Bypass of Filter for Air Sucked Into instrument.Filter-in Lock Adjusted ML20071F0861980-09-25025 September 1980 Ro:On 800912,sample Analysis Taken from Hydrazine Addition Tank Indicated Sodium Chloride in Tank.Anonymous Telcon Indicated Salt May Have Been Added Prior to Labor Strike by Unknown Persons ML20058L3431978-07-31031 July 1978 Ro:On 780728,control Rod Drive 30-47 Delayed Approx 1.4 Before Scramming.Buna N Disk in Plunger Broken in Pieces.Plungers on 242 Scram Pilot Valves & Two Backup Scram Pilot Valves Removed & Replaced ML20090L8311978-06-0202 June 1978 Ro:On 780505,steam Leak Noted in RCIC Inlet Steam Line & Drain Line to Condenser.Caused by Pinhole Failure on Weld on 300 Lb Socket Weld.Hole Temporarily Patched ML20091A9941978-03-10010 March 1978 Ro:On 780309,smear Survey of Chem Nuclear Sys Inc Model 4-45 Shipping Cask Disclosed Max Surface Contamination of 25,900 Disintegrations Per Min Per 100 Square Centimeters.Cask Will Be Decontaminated ML20127G6171978-02-0202 February 1978 Advises That on 780202,during Surveillance Test,One Suppression Chamber to Drywell Vacuum Breaker Failed to Reclose Following Exercise.Plant Shutdown Initiated ML20086D5141978-01-0606 January 1978 Telecopy Ro:On 780105,discovered That One of Two Nuclear Engineering Co Model B3-1 Shipping Casks Provided w/1-inch Diameter Lid Bolts Rather than 1-1/4 Inch Size Specified in Certificate of Compliance 6058 ML20086D5201977-12-14014 December 1977 Telecopy Ro:Heating Steam Coil Leak in Reactor Bldg Ventilation Supply Unit V-AH-4A Resulted in Freezing of Condensate at Inlet to Unit & Subsequent Inoperability of Associated Secondary Containment Isolation Dampers ML20086D5371977-10-14014 October 1977 Telecopy Ro:Insp of Internal Torus Catwalk Support Structure Revealed That Catwalk Mitered Sections Not All Attached to Horizontal Catwalk Support Plates in Some Manner.Attachment Locations Will Be Upgraded ML20086D5501977-10-13013 October 1977 Telecopy Ro:On 771012,local Leak Rate Testing of MSIV AO-2-80A & Nitrogen Instrument Air Sys Isolation Valve CV-7436 Indicated That Leakage Exceeded Tech Spec Acceptance Criteria.Cause Under Investigation ML20086D5541977-10-0505 October 1977 Telecopy Ro:On 771004,local Leak Rate Testing of HPCI Sys Discharge Isolation Check Valve HPCI-9 Indicated That Leakage Exceeded Tech Spec Acceptance Criteria.Cause Under Investigation ML20086D5571977-09-29029 September 1977 Telecopy Ro:On 770929,local Leak Rate Testing of Core Spray Inboard Isolation Check Valve AO-14-13A Indicated That Leakage Exceeded Tech Spec Acceptance Criteria.Cause Under Investigation ML20086D5611977-09-14014 September 1977 Telecopy Ro:On 770913,local Leak Rate Testing of Core Spray Inboard Isolation Check Valve AO 14-13B Indicated That Leakage Exceeded Tech Spec Acceptance Criteria.Related Event on 770914 ML20086D5671977-09-12012 September 1977 Telecopy Ro:Main Steam Drain Isolation Valve MD 2373 & Main Steam Outboard Isolation Valve AO 2-86A Exceeded Tech Spec Acceptance Criteria for Local Leak Rate Tests ML20086D6421977-07-11011 July 1977 Telecopy Ro:On 770709,determined That Recombiner Sys a Offgas Flow Control Valve PCV 7489A Could Be Opened W/ Controlling Solenoid Valve Deenergized.Valve Held from Svc Pending Investigation ML20137G4461977-06-23023 June 1977 Ro:On 770621,radioactive Source Containing 200 Mci Cs-137 Recovered from Brine Well 33.Incident Described in ML20086F0801977-06-0606 June 1977 Ro:On 770506,plant Iodine & Particulate Release Rate Exceeded 4% of Facility Tech Spec Averaged Over Second Calendar Quarter of 1977.Caused by Fuel Perforations Coupled W/End of Cycle Testing & Reactor Coolant & Steam Leaks ML20058K6111977-03-0909 March 1977 Ro:On 770223,discovered Withdrawal of in-sequence Control Rod Resulted in Period Less than 5-s & IRM Scram 1998-01-29
[Table view] Category:TEXT-SAFETY REPORT
MONTHYEARML20217D1261999-09-30030 September 1999 Monthly Operating Rept for Sept 1999 for Monticello Nuclear Generating Plant.With ML20216E7031999-08-31031 August 1999 Monthly Operating Rept for Aug 1999 for Monticello Nuclear Generating Plant.With ML20210Q0521999-08-0404 August 1999 Safety Evaluation Approving Relief Request 10 to License DPR-22 Per 10CFR50.55a(g)(6)(i).Inservice Exam for Relief Request 10,Parts A,B,C,D & E Impractical & Reasonable Assurance of Structural Integrity Provided ML20210Q6611999-07-31031 July 1999 Monthly Operating Rept for July 1999 for Monticello Nuclear Generating Plant.With ML20209F7901999-06-30030 June 1999 Monthly Operating Rept for June 1999 for Monticello Nuclear Generating Plant.With ML20195H0351999-05-31031 May 1999 Monthly Operating Rept for May 1999 for Monticello Nuclear Generatintg Plant.With ML20206N1721999-04-30030 April 1999 Monthly Operating Rept for Apr 1999 for Monticello Nuclear Generating Plant.With ML20205N0861999-04-12012 April 1999 Safety Evaluation Re Licensee Response to GL 95-07, Pressure Locking & Thermal Binding of Safety-Related Power-Operated Gate Valves ML20205P5701999-03-31031 March 1999 Monthly Operating Rept for Mar 1999 for Monticello Nuclear Generating Plant.With ML20204H4951999-03-18018 March 1999 SER Concluding That Licensee Established Acceptable Program to Verify Periodically design-basis Capability of safety-related MOVs at Monticello.Therefore Staff Concludes Licensee Adequately Addressed Action Required in GL 96-05 ML20205G7391999-02-28028 February 1999 Monthly Operating Rept for Feb 1999 for Monticello Nuclear Generating Plant.With ML20202F7901999-01-25025 January 1999 1999 Four Year Simulator Certification Rept for MNGP Simulation Facility ML20199E4871999-01-0606 January 1999 SER Accepting Licensee 951116,960214 & 0524 Responses to NRC Bulletin 95-002, Unexpected Clogging of Residual Heat Removal Pump Strainer While Operating in Suppression Pool Cooling Mode ML20205H0561998-12-31031 December 1998 Northern States Power Co 1998 Annual Rept. with ML20199F6211998-12-31031 December 1998 Monthly Operating Rept for Dec 1998 for Mngp.With ML20198P0691998-12-28028 December 1998 Safety Evaluation Concluding That NSP Proposed Alternative to Paragraph III-3411 of App III to 1986 Edition of Section XI of ASME Code Provides Acceptable Level of Quality & Safety.Alternative Authorized ML20198D0751998-12-10010 December 1998 Safety Evaluation Supporting NSP Proposed Change to EOPs to Use 2/3 Core Height as Potential Entry Condition Into Containment Flooding ML20198B2531998-11-30030 November 1998 Monthly Operating Rept for Nov 1998 for Monticello Nuclear Generating Plant.With ML20195E3691998-11-12012 November 1998 Safety Evaluation Concluding That Licensee USI A-46 Implementation Has Met Purpose & Intent of Criteria in GIP-2 & Staff Sser 2 for Resolution of USI A-46 ML20195D2381998-10-31031 October 1998 Monthly Operating Rept for Oct 1998 for Monticello Nuclear Generating Plant.With ML20198J4451998-10-22022 October 1998 Rev 2 to SIR-97-003, Review of Test Results of Two Surveillance Capsules & Recommendations for Matls Properties & Pressure-Temp Curves to Be Used for Monticello Rpv ML20154L3471998-09-30030 September 1998 Monthly Operating Rept for Sept 1998 for Monticello Nuclear Generating Plant.With ML20153F0511998-09-21021 September 1998 Rev 2 to MNGP Colr,Cycle 19 ML20153E9361998-09-0808 September 1998 Rev 1 to MNGP Colr,Cycle 19 ML20153B0861998-08-31031 August 1998 Monthly Operating Rept for Aug 1998 for Monticello Nuclear Generating Plant.With ML20237B8461998-07-31031 July 1998 Monthly Operating Rept for July 1998 for Monticello Nuclear Generating Plant ML20236W5041998-07-21021 July 1998 ISI Exam Summary Rept - Refueling Outage 19 ML20236R1941998-06-30030 June 1998 Monthly Operating Rept for June 1998 for Monticello Nuclear Generating Plant ML20249A5861998-05-31031 May 1998 Monthly Operating Rept for May 1998 for Monticello Nuclear Generating Plant ML20247K3971998-04-30030 April 1998 Monthly Operating Rept for Apr 1998 for Monticello Nuclear Generating Plant ML20217D8731998-04-13013 April 1998 Rev 0 to MNGP Colr,Cycle 19 ML20217F6431998-03-31031 March 1998 Monthly Operating Rept for Mar 1998 for Monticello Nuclear Generating Plant ML20216D1041998-03-0505 March 1998 Rev 21 to Operational QA Plan ML20216H6481998-02-28028 February 1998 Monthly Operating Rept for Feb 1998 for Monticello Nuclear Generating Plant ML20203G1431998-02-10010 February 1998 Rev 2 to Inservice Insp Exam Plan,Third Interval,920601- 020531 ML20203B2821998-01-31031 January 1998 Monthly Operating Rept for Jan 1998 for Monticello Nuclear Generating Station ML20202F9161998-01-29029 January 1998 Special Rept:On 980128,two of Three Fire Protection Pumps Were Removed from Svc as Result of Sys Configuration Necessary to Support Planned Maintenance.Fire Pumps Were Returned to Svc on 980128 ML20216D2071997-12-31031 December 1997 1997 Annual Rept for Northern States Power Co ML20198P2201997-12-31031 December 1997 Monthly Operating Rept for Dec 1997 for Monticello Nuclear Generating Plant ML20197J8131997-12-31031 December 1997 Revised Evacuation Time Estimates for Plume Exposure Pathway Emergency Planning Zone at Monticello Nuclear Power Plant. W/One Oversize Drawing ML20203J7131997-11-30030 November 1997 Monthly Operating Rept for Nov 1997 for Monticello Nuclear Generating Plant ML20199G7051997-11-19019 November 1997 Safety Evaluation Authorizing Relief Request 8 of Third 10 Yr Inservice Insp Interval ML20199H8181997-10-31031 October 1997 Monthly Operating Rept for Oct 1997 for Monticello Nuclear Generating Plant ML20217K2081997-09-30030 September 1997 Monthly Operating Rept for Sept 1997 for Monticello Nuclear Generating Plant ML20216H7771997-08-31031 August 1997 Monthly Operating Rept for Aug 1997 for Monticello Nuclear Generating Plant ML20217K2741997-07-31031 July 1997 Monthly Operating Rept for Jul 1997 for Monticello Nuclear Generating Plant ML20196H1081997-07-0808 July 1997 Rev 20 to Operational QA Plan ML20149E2921997-06-30030 June 1997 Monthly Operating Rept for June 1997 for MNGP ML20141B9271997-06-30030 June 1997 LOCA Containment Analyses for Use in Evaluation of NPSH for RHR & Core Spray Pumps ML20148S6341997-06-23023 June 1997 NPSH - Rept of Sulzer Bingham Pump 1999-09-30
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NORTHERN STATES POWER COMPANY Minneapolis, Minnesota 55401 cp 9 g g"J5 s Ap ril 29,1971 e + b !
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%$' s off l Dr. Peter A. Morris, Director Division of Reactor Licensing
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Dear. Dr. Morris:
MONTl CELLO NUCLEAR GENERATING PLANT Docket No. 50-263 License No. DPR-22 Inoperability of the Air Ejector Off-Gas System Radiation Monitors On April 20, 1971, it was determined that the two air ejector off-gas monitors have been inoperable during the startup testing program to the 25%
power level. We are reporting this occurrence in accordance with Section 6.6.B.3 of Appendix A, Technical Specifications, of the Provisional Operating License DPR-22.
Summarv Descrintinn or Occurrence During the startup testing program, while initially escalating to each power level, daily grab samples of the air ejector of f-gas are analyzed.
During the initial rise to 15% power, the air ejector activity discharge was approximately 25 uci/see with a corresponding stack release rate of approximately 15 uci/sec. These activity rates existed at the time of the 3-10-71 shutdown from 15% power. Following an extended shutdown the plant was restarted and reached 13% power on 4-19-71 with an air, ejector activity discharge of approximately 120 uci/see with a stack release rate of ap On 4-20-71 during the initial rise to 25% power, proximately the analysis of an off-gas45 grabuci/sec.
sam y activity discharge ,to be approximately 300sec. uci/ple Withshowed the air ejector this analyzed activity, it was expected that the air ejector off-gas monitors should be indicating noticeably above the indication provided by the bug sources. While investigating this concern, it was discovered that the monitor indications increased from 2.8 mr/hr to approximately 9 mr/hr when the Off-Gas Sample Chamber Purge controls were turned to the ON position. It was then recognized that the system was operating normally with the controls indicating a purge condition. The system was operated in this manner until the plant was shutdown.
Further investigation of the problem revealed that the air ejector sample chamber purge valve was hooked up improperly. The valve is a three way valve which should allow purging of the sample chamber when the valve solenoid is energized and provide normal sampling when the valve is de-energized. The valve was found piped up the opposite way and apparently
-71 "O 8709250169 870921 PDR FOIA -M NENZ87-111 PDR r / ? 'l / a
4 had been 'in this condition since initial installation. .Following a i the system was piped up croperly and ~
.during plant shutdown a plant restart on on April Ap r25th,il 26th, proper operation of the system was verified. .l The Region til Compliance Office has been previously rotified of' the occurrence in accordance with Section 6.6. A.3 of the Technical Specifications. {
.Yours ver truly,
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. R.0. Duncanson, Jr., P.E.
Gen; Supt. of Power Plants-Mechanical-Chairman Monticello Safety Audit Committee -
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NSF NORTHERN STATES POWER COMPANY Minneapolis, Minnesota 55401 i Regulatory File Cy.
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"- r i A 1 S. Peter A. Morris, Director ; MAY 5 1971 *g5 01- 4 v L i Civision of Reactor Licensing g gugY 6
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MOMTiCELLO NJCLEAR GENERATlNG PLANT Docket No. 50-263 License No. DPR-22 Safety / Relief Valve Settings Exceeding 1080 PSIG A condition occurred at the Monticello Nuclear Generating Plant which is reportable to your office in accordance with the provisions of Appendix A, Technical Specifications, of the Provisional Operating License DPR-22. The cccurrence was classified as an Abnormal Occurrence as defined in Section i. A.1 c' the Technical Specifications and requires reporting in accordance with Section 6.6.B.3 of the Specifications. The Region ll1 Compliance Office has been notified in accordance with the requirements of Section 6.6. A of the Technical Specifications.
Summarv Dencrintion of the Occurrence Analysis of reactor pressure data recorded during the " Loss-c f-Offsite-Power" test performed on pA ril 22, 1971, indicated that the initiation setpoints of the four reactor coolant system safety / relief valves might be above the Technical Specification limit of 1080 psig. Calibration checks were f:ormed on the pressure instrumentation and the settings of the safety /per-relief valves were tested under cold conditions, using nitrogen pressure.
These checks and tests indicated that the settings of three valves were above 1095 psig. The other valve was set at about 1080 psig.
All four valves were adjusted to initiate at less than 1080 psig.
Detailed Description and Analvsis As part of the startup test program, a " Loss-of-Offsite-Power" test was performed at 25% of rated power. This test, as expected, resulted in a reactor pressure transient. The wide range pressure recorder in the control room indicated that reactor pressure had increased to 1087 psig within approximately 24 seconds following the test initiation. At this time safety / relief valve RV-2-71 A opened, as indicated by a drop in pressure, a sharp increase in RV. 2-71 A discharge temperature and indication from an accelerometer mounted on the valve. Pressure was reduced to 1042 psig gjp;c;;; E6f 0
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within.8 secones and the valve closed. During the next 3[ minutes the pressure increased slowly to a peak value of 1100 psig, as indicated by the wide rari;e recorder. The Disturbance Log, printed by the plant computer, showed a peak pressure of 1104 psig at this time. Then RV-2-71 A opened a second time. Pressure was reduced to 1048 psig within 8 seconds.
~ Pressure then slowly increased to a peak of 1067 psig .followed by a steady decrease.
The indication that the second initiation had occurred at a pressure 13 psi, above.tbe first initiation was puzzling. .Also, since none of the.renaining valves had opened, it seemed that the settings of the remaining valves were even higher.
The first initiation at 1087-psig would'not have been considered unusual by itself. The ASME code requires a setpoint tolerance of one percent.
' This means the ' valves could initiate as much as 11 psig above the nominal 1080 psig setting. Also, considering the various accuracy tolerances associated with the pressure instrumentation, the recorded pressure could be in error by up to z 9 psig. Additional errors can occur due to recorder chart variatior.s. Similarly, the computer Disturbance Log .could be in error by up to 6.5 psig. Even considering all of these possible it appeared that at least three valves were set substantially above errors,ig.
1080 ps Further investigation was therefore considered necessary.
A calibration check of the recorder and the computer point was performed.
. At 1100 psig the recorder error was found to be + 5 psi and the computer error was founc to be + 9 psi. Based on this calibration it appeared '
that the first initiation of RV-2-71 A. occurred at 1082 psig and the second initiation at 1995 psig.
The four safety / relief valves were inspected under the direction of the I manufacturer's representative and the opening pressures of the first stage l pilot valves were tested under ambient temperature conditions using nitrogen pressure. These tests and inspections showed the following:
l l RV-2-71A: The setting was essentially correct.
RV-2-718: The setting of the setpoint adjustment nut was found to be correct. However, an improper length dowel pin was found to have compressed the setpoint adjusting I spring beyond the proper setting when the bonnet cap which covers the adjustment nut was bolted in
, pl ace. This caused the actual initiation pressure to be at least 1110 psig.
RV-2-710: The setting was found to be approximately 1100 psig.
A slight leak in the first stage pilot valve made it RV-2-71 D:
impossible to accurately determine the setpoint without special test equipment. However, it can be inferred that the setting was probably greater than 1095 psig.
'A
The observed 13 psi increase in setpoint for the second initiation of RV-2-71 A is attributed to the effect of temperature on the valve actuating system.' Wher, a valve is initiated, flow through the upper portions of the valve mechanism apparentl setpoint increase.-
y results The in sufficient additional manufacturers heating to representative affect stated thataan temporary approximately 15 increase in ,setpoint would be expected as the valve is heated to. normal operating temperature. This is confirmed by the results of the ambient temperature tests which showed the RV-2-71 A opening, point to be 1070 psig with. nitrogen, whereas it had initially opened during the loss of power test at about 1082 psig.
Correctiv. Actions
, The first stage pilot in RV-2-71D was repaired; the dowel pin in RV-2-71B was shortened to proper length; and all four valves were adjusted, at ambient temperature, to: initiate at less than the equivalent of 1080 psig at normal operating temperature.
Conclusions The manufacturers certification of pressure setting had been obtained for all four valves prior to initial plant operation. However, only one of the four valves was found to be properly set. Two valves were apparently not properly adjusted and one valve was affected by an improper length dowel pin.
There is reasorable confidence that the valves are presently set properly.
The test gauge used to adjust the valve settings was compared with an accurate dead weight test _ set before and after making the adjustments.
During the remainder of the startup test program particular effort will. be made to monitor the safety / relief valve performance during transient tests.
Yours very truly, 744p P.E.
R.O. Duncanson, Gen. Supt. of PowerJr. , Plants-Mechanical Chairman Monticello Safety Audit Committee ROD /fMC/ car k
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