LER-1979-006, /03L-0 on 790322:packing leak-off Observed on Three Valves.Cause Undetermined for Two Valves.Leaking Packing on Third Due to Broken Bellows Seal.Unit in Reeling Shutdown;Repairs Will Be Made Before Return to Power |
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packing leak-off to the. RCDT from pressurizer valves.
'tlinor leakage from a swagelok,fitting at. the incore detector seal table was also observed.
I Following evaluation by'he Plant Nuclear Safety Committee, the unit was
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~6'aulsaNczslr 30 41 The cause of the ackin leak-off could not be determined on two of'he valves.
The leaking packing on the third. vajve was due to a broken bellows seal.
The unit is currently in refueling shutdown and repairs I
2 will be completed prior to returning to power.
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0 REPORTABLE OCCURRENCE 251-79-6, LICENSEE EVENT REPORT P
E AG TWO Additional Event Descri tion and Probable Conse uences The Plant Nucleary Safety Committee (PNSC) 'reviewed the evaluation of the Unit 4 Reactor Coolant System leakage rate that was in excess of 1 gpm.
The sequence of events and the evaluation follows:
By 3:00 PH, March 20, 1979, it was tentatively determined that the source of the excess leakage was from:
(1)
Xhe 4A Reactor Coolant Pump number' seal leak-off as there were periodic, standpipe "high. level" alarms, (2)
'valve packing leak-off to the Reactor Coolant Drain Tank (RCDT) as
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observed by periodically needing to quench the Reactor Coolant Drain Tank to maintain temperature below 180'F,.and (3) the 4A and 4B charging pump seal pots overflowing.
The leak rate remained stable at approximately 1.60 gpm through 7iednesday, March 21,'1979.
By about 7:00 AH on Thursday,.Harch 22, 1979, the leak rate had increased to 1.85 gpm and by 12:30 PH had increased to 2.85 gpm.
At about 1 35 PH, the decision was made to place the reactor in hot shutdown in order to make entry inside the containment biological shield to determine the source of the increased leak rate.
The reactor was in hot shutdown at about 2:40 PH.
At 4:45 PH, a containment entry was made.
The source of the leaks was found to be valve packing leak-offs to the RCDT from pressurizer valves HOV-4-535, HOV-4-536 and PCV-4-455A.
In addition,. a minor leak was found from a swagelok fitting at the incore detector seal table for one of the score detector thimbXes that was draining to the containment sump.'ll leaks were evaluated as minor.
At about 8:30 AH on Friday, Harch 23, 1979, a second containment entry was made to ensure that all leakage areas had been identified and that the leakage at the incore detector seal table had not increased.
No additional leaks were found and the leak rate at the incore detector seal table had not increased above the orig-inal leak rate observed.
Unit 4 was returned to service at about 2:40 PH on Friday, March 23, 1979.
The PNSC agreed with the evaluation that the leakage rate was minor.and recommended
- the leak rate be checked once per each 8 hour9.259259e-5 days <br />0.00222 hours <br />1.322751e-5 weeks <br />3.044e-6 months <br /> shift in order to monitor trends in the water inventory.
The PNSC determined operation of Unit 4 with this leakage would not involve any unreviewed safety questions.
At about 7:00 AH on Tuesday, March 20, 1979, the routine calculation of RCS leak rate indicated a leak rate of 1.27 gpm.-. An investigation was initiated to determine the source of this, excess leakage.
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| 05000251/LER-1979-001, Forwards LER 79-001/03L-0 | Forwards LER 79-001/03L-0 | | | 05000251/LER-1979-001-03, /03L-0 on 790125:4A Boric Acid Transfer Pump Tripper on Thermal Overload Inoperable.Caused by Incomplete Reinstallation of Recirculation Line Insulation.New Recirculation Line Installed | /03L-0 on 790125:4A Boric Acid Transfer Pump Tripper on Thermal Overload Inoperable.Caused by Incomplete Reinstallation of Recirculation Line Insulation.New Recirculation Line Installed | | | 05000250/LER-1979-001-31, /031-0 on 790213:A Fire Pump Found to Be Inoperable.Caused by Improper Operation of Power Supply Breaker.Procedural Methods Implemented to Ensure That Fire Pump Power Is Verified After Each Shift | /031-0 on 790213:A Fire Pump Found to Be Inoperable.Caused by Improper Operation of Power Supply Breaker.Procedural Methods Implemented to Ensure That Fire Pump Power Is Verified After Each Shift | | | 05000250/LER-1979-001, Forwards LER 79-001/031-0 | Forwards LER 79-001/031-0 | | | 05000250/LER-1979-002, Update to LER 79-002/03X-1 on 790226:during Refueling Shutdown,Crack Found in Weld on Drain Line in B Accumulator Discharge Piping.Caused by Stress Due to Line Vibration. Elbows & Welds Replaced | Update to LER 79-002/03X-1 on 790226:during Refueling Shutdown,Crack Found in Weld on Drain Line in B Accumulator Discharge Piping.Caused by Stress Due to Line Vibration. Elbows & Welds Replaced | | | 05000251/LER-1979-002, Forwards LER 79-002/03L-0 | Forwards LER 79-002/03L-0 | | | 05000251/LER-1979-002-03, /03L-0 on 790310:during Cold Shutdown,Cracks Observed in 4B Charging Pump Suction Piping.Probably Caused by Design/Installation of Positive Displacement Pumps. Welds Repaired & Mods Made to Reduce Stresses | /03L-0 on 790310:during Cold Shutdown,Cracks Observed in 4B Charging Pump Suction Piping.Probably Caused by Design/Installation of Positive Displacement Pumps. Welds Repaired & Mods Made to Reduce Stresses | | | 05000251/LER-1979-003, Forwards LER 79-003/03L-0 | Forwards LER 79-003/03L-0 | | | 05000250/LER-1979-003-01, /01T-0:on 791101,NSSS Vendor Identified & Corrected Input Error in Two LOCA Analyses.Caused by Use of Incorrect Method.Procedures Revised | /01T-0:on 791101,NSSS Vendor Identified & Corrected Input Error in Two LOCA Analyses.Caused by Use of Incorrect Method.Procedures Revised | | | 05000251/LER-1979-003-03, /03L-0 on 790315:during Normal Operation,Crack Observed in 4C Charging Pump Suction Piping.Caused by Design/Installation of Pumps Resulting in Operational Pressure Pulsation/Vibration Effects.Weld Repaired | /03L-0 on 790315:during Normal Operation,Crack Observed in 4C Charging Pump Suction Piping.Caused by Design/Installation of Pumps Resulting in Operational Pressure Pulsation/Vibration Effects.Weld Repaired | | | 05000251/LER-1979-004, Forwards LER 79-004/03L-0 | Forwards LER 79-004/03L-0 | | | 05000251/LER-1979-004-03, /03L-0 on 790315:vendor Reported Main Steam Line Mechanical Snubber,Returned for Routine Testing,Was in locked-up Condition.Caused by Damaged Thrust Bearing. X-stop Adjusted | /03L-0 on 790315:vendor Reported Main Steam Line Mechanical Snubber,Returned for Routine Testing,Was in locked-up Condition.Caused by Damaged Thrust Bearing. X-stop Adjusted | | | 05000251/LER-1979-005-03, /03L-0 on 790322:process Radiation Monitors R-11 & R-12 Were Out of Svc.Caused by Failure of Air Sampling Blower Which Supplies Monitors.Blower Replaced & Monitors Returned to Svc | /03L-0 on 790322:process Radiation Monitors R-11 & R-12 Were Out of Svc.Caused by Failure of Air Sampling Blower Which Supplies Monitors.Blower Replaced & Monitors Returned to Svc | | | 05000251/LER-1979-005, Forwards LER 79-005/03L-0 | Forwards LER 79-005/03L-0 | | | 05000251/LER-1979-006, Forwards LER 79-006/03L-0 | Forwards LER 79-006/03L-0 | | | 05000251/LER-1979-006-03, /03L-0 on 790322:packing leak-off Observed on Three Valves.Cause Undetermined for Two Valves.Leaking Packing on Third Due to Broken Bellows Seal.Unit in Reeling Shutdown;Repairs Will Be Made Before Return to Power | /03L-0 on 790322:packing leak-off Observed on Three Valves.Cause Undetermined for Two Valves.Leaking Packing on Third Due to Broken Bellows Seal.Unit in Reeling Shutdown;Repairs Will Be Made Before Return to Power | | | 05000251/LER-1979-007-01, /01T-0 on 790519:inoperable Pipe Support 4-VCH-105 Reported by Insp Team.Cause Unknown.Pipe Support to Be Restored Per Approved Procedures | /01T-0 on 790519:inoperable Pipe Support 4-VCH-105 Reported by Insp Team.Cause Unknown.Pipe Support to Be Restored Per Approved Procedures | | | 05000251/LER-1979-008-03, /03X-1 on 790526:while Safeguards Sys Was Being tested,4A 4,160-volt Bus Failed to Strip in Required Time, Causing Emergency Diesel Generator to Stop.Cause Not Determined.Testing Procedures Revised | /03X-1 on 790526:while Safeguards Sys Was Being tested,4A 4,160-volt Bus Failed to Strip in Required Time, Causing Emergency Diesel Generator to Stop.Cause Not Determined.Testing Procedures Revised | | | 05000251/LER-1979-008, Forwards LER 79-008/03X-1 | Forwards LER 79-008/03X-1 | | | 05000251/LER-1979-009, Forwards LER 79-009/03L-1 | Forwards LER 79-009/03L-1 | | | 05000250/LER-1979-009-03, During Refueling Shutdown,Leak Observed from Temporary Level Indication Line Near Base of Refueling Water Storage Tank.Cause Undetermined.Integrity of Piping & Instrumentation Verified | During Refueling Shutdown,Leak Observed from Temporary Level Indication Line Near Base of Refueling Water Storage Tank.Cause Undetermined.Integrity of Piping & Instrumentation Verified | | | 05000250/LER-1979-009, Forwards Updated LER 79-009/03X-1 | Forwards Updated LER 79-009/03X-1 | | | 05000251/LER-1979-009-03, /03L-1:on 790611,mechanical Snubber on Steam Generator C Feedwater Line Found in locked-up Condition. Caused by Snubber Overload Resulting in Damage to Thrust Bearing.Snubber Will Be Replaced w/50,000 Lb Rated Snubber | /03L-1:on 790611,mechanical Snubber on Steam Generator C Feedwater Line Found in locked-up Condition. Caused by Snubber Overload Resulting in Damage to Thrust Bearing.Snubber Will Be Replaced w/50,000 Lb Rated Snubber | | | 05000251/LER-1979-010-01, /01T-0 on 790626:NSSS Vendor Notified Util of Potential Level Bias Which Could Delay Reactor Trip & Feedwater Initiation or Cause False Level Indications. License Amend Will Be Proposed to Increase Sys Setpoint | /01T-0 on 790626:NSSS Vendor Notified Util of Potential Level Bias Which Could Delay Reactor Trip & Feedwater Initiation or Cause False Level Indications. License Amend Will Be Proposed to Increase Sys Setpoint | | | 05000251/LER-1979-010, Forwards LER 79-010/01T-0 | Forwards LER 79-010/01T-0 | | | 05000250/LER-1979-010-03, /03X-1 on 790319:excessive Leakage Noted at Inner Personnel Airlock Door/Bulkhead.Caused by Packing Leak Along Operating Shaft at Inner Bulkhead.Local Leak Test Completed Successfully | /03X-1 on 790319:excessive Leakage Noted at Inner Personnel Airlock Door/Bulkhead.Caused by Packing Leak Along Operating Shaft at Inner Bulkhead.Local Leak Test Completed Successfully | | | 05000250/LER-1979-010, Forwards LER 79-010/03X-1 | Forwards LER 79-010/03X-1 | | | 05000251/LER-1979-011-03, Charging Sys Performance Noted to Be Degraded During Routine Startup Operation.Caused by Ruptured Diaphragm & Damaged O-ring on Valve.Valve Repaired & Pumps Vented | Charging Sys Performance Noted to Be Degraded During Routine Startup Operation.Caused by Ruptured Diaphragm & Damaged O-ring on Valve.Valve Repaired & Pumps Vented | | | 05000251/LER-1979-011, Forwards Updated LER 79-011/03X-1 | Forwards Updated LER 79-011/03X-1 | | | 05000251/LER-1979-012, Forwards LER 79-012/03L-0 | Forwards LER 79-012/03L-0 | | | 05000251/LER-1979-012-03, /03L-0:on 790806,periodic Test of T & delta-T Not Completed within Required Time Limit Due to Investigation of Unit Trip.Surveillance Completed Following Recovery from Unit Trip | /03L-0:on 790806,periodic Test of T & delta-T Not Completed within Required Time Limit Due to Investigation of Unit Trip.Surveillance Completed Following Recovery from Unit Trip | | | 05000251/LER-1979-013-03, /03L-0:on 790815,charging Pump 4A Removed from Svc Due to Excessive Seal Leakage.Cause Under Investigation. Seal Was Replaced & Pump Tested & Returned to Svc | /03L-0:on 790815,charging Pump 4A Removed from Svc Due to Excessive Seal Leakage.Cause Under Investigation. Seal Was Replaced & Pump Tested & Returned to Svc | | | 05000251/LER-1979-013, Forwards LER 79-013/03L-0 | Forwards LER 79-013/03L-0 | | | 05000251/LER-1979-014-01, /01T-0:on 790828,during Performance of Evaluation to Place Spent Fuel Pit Purification Demineralizer in Svc, 3,000 Gallon Overflow Occurred.Caused by Incomplete Communication & Failure to Follow Procedure.Unit Cleaned | /01T-0:on 790828,during Performance of Evaluation to Place Spent Fuel Pit Purification Demineralizer in Svc, 3,000 Gallon Overflow Occurred.Caused by Incomplete Communication & Failure to Follow Procedure.Unit Cleaned | | | 05000251/LER-1979-014, Forwards LER 79-014/01T-0 | Forwards LER 79-014/01T-0 | | | 05000250/LER-1979-014, Forwards LER 79-014/03L-0 | Forwards LER 79-014/03L-0 | | | 05000250/LER-1979-014-03, /03L-0 on 790424:ready to Start Light on B Emergency Diesel Generator Engine Control Panel Failed. Caused by Vibration of Lamp Socket.Tests Under Way to Determine If Neon Unit Would Be Better Suited | /03L-0 on 790424:ready to Start Light on B Emergency Diesel Generator Engine Control Panel Failed. Caused by Vibration of Lamp Socket.Tests Under Way to Determine If Neon Unit Would Be Better Suited | | | 05000251/LER-1979-015-03, /03L-0:on 790829,during Power operation,4A Boric Acid Transfer Pump Tripped on Thermal Overload & Declared Inoperable.Caused by Boric Acid Solidification in Recirculation Line.Recirculation Line Insulated | /03L-0:on 790829,during Power operation,4A Boric Acid Transfer Pump Tripped on Thermal Overload & Declared Inoperable.Caused by Boric Acid Solidification in Recirculation Line.Recirculation Line Insulated | | | 05000250/LER-1979-015-03, /03L-0 on 790426:B Emergency Diesel Generator Failed Loading Acceptance Criteria.Caused by Cracked half-inch Nipple to Fuel Pump Which Resulted in Partial Fuel Starvation.Nipple Replaced & Old Nipple Reanalyzed | /03L-0 on 790426:B Emergency Diesel Generator Failed Loading Acceptance Criteria.Caused by Cracked half-inch Nipple to Fuel Pump Which Resulted in Partial Fuel Starvation.Nipple Replaced & Old Nipple Reanalyzed | | | 05000250/LER-1979-015, Forwards LER 79-015/03L-0 | Forwards LER 79-015/03L-0 | | | 05000251/LER-1979-015, Forwards LER 79-015/03L-0 | Forwards LER 79-015/03L-0 | | | 05000251/LER-1979-016, Forwards LER 79-016/03L-0 | Forwards LER 79-016/03L-0 | | | 05000251/LER-1979-016-03, /03L-0:on 790830,boric Acid Transfer Pump Failed to Start.Caused by Malfunction of Line Starter.Contacts Were Cleaned & Pump Was Returned to Svc | /03L-0:on 790830,boric Acid Transfer Pump Failed to Start.Caused by Malfunction of Line Starter.Contacts Were Cleaned & Pump Was Returned to Svc | | | 05000250/LER-1979-016, Forwards LER 79-016/03L-0 | Forwards LER 79-016/03L-0 | | | 05000250/LER-1979-016-03, /03L-0 on 790429:high Level Alarm Annunciated. Caused by Instrument Drift of Tech Spec Min & High Level Alarms & Digital Level Indicator Transducer.Instruments Recalibr | /03L-0 on 790429:high Level Alarm Annunciated. Caused by Instrument Drift of Tech Spec Min & High Level Alarms & Digital Level Indicator Transducer.Instruments Recalibr | | | 05000251/LER-1979-017-03, /03L-0:on 790903,condensate Water Tank Contained Less than 185,000 Gallons Required by Tech Specs.Caused by Increased Water Demand for Steam Generator Blowdown & Reduced Water Treatment Plant Output | /03L-0:on 790903,condensate Water Tank Contained Less than 185,000 Gallons Required by Tech Specs.Caused by Increased Water Demand for Steam Generator Blowdown & Reduced Water Treatment Plant Output | | | 05000251/LER-1979-017, Forwards LER 79-017/03L-0 | Forwards LER 79-017/03L-0 | | | 05000250/LER-1979-017-03, /03X-1 on 781218:during Normal Operation,Efforts Were Made to Determine Source of Intermittent Radioactive Gas Leak.Caused by Possible Deformation of Small Section of Tank Shell.Defect Will Be Repaired | /03X-1 on 781218:during Normal Operation,Efforts Were Made to Determine Source of Intermittent Radioactive Gas Leak.Caused by Possible Deformation of Small Section of Tank Shell.Defect Will Be Repaired | | | 05000251/LER-1979-018-03, /03L-0:on 790911,charging Pump 4C Removed from Svc Due to Excessive Seal Leakage.Cause Not Given.Seal Was Replaced & Pump Returned to Svc.Evaluation Continues | /03L-0:on 790911,charging Pump 4C Removed from Svc Due to Excessive Seal Leakage.Cause Not Given.Seal Was Replaced & Pump Returned to Svc.Evaluation Continues | | | 05000251/LER-1979-018, Forwards LER 79-018/03L-0 | Forwards LER 79-018/03L-0 | |
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