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Category:DEFICIENCY REPORTS (PER 10CFR50.55E & PART 21)
MONTHYEARML20206H2611999-05-0505 May 1999 Part 21 Rept Re Defect Found in Potter & Brumfield Relays. Sixteen Relays Supplied in Lot 913501 by Vendor as Commercial Grade Items.Caused by Insufficient Contact Pad Welding.Relays Replaced with New Relays ML20207M9231999-03-12012 March 1999 Amended Part 21 Rept Re Cooper-Bessemer Ksv EDG Power Piston Failure.Total of 198 or More Pistons Have Been Measured at Seven Different Sites.All Potentially Defective Pistons Have Been Removed from Svc Based on Encl Results 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 ML17229A8781998-10-19019 October 1998 Part 21 Rept Re Potential Defect in Swagelok Stainless Steel Front Ferrule,Part Number SS-503-1,which Was Machined with Improper Length.Insp Equipment That Will 100% Identify Short Length ML17229A8871998-10-19019 October 1998 Part 21 Rept Re Potential Defect in Swagelok Stainless Steel Front Ferrule,Part Number SS-503-1 Which Was Machined with Improper Length.C/A Includes Insp Equipment That Will 100% Identify Short Length 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 ML20236N3871998-07-0909 July 1998 Part 21 Rept Re Deficiency Identified in Event 32725, Corrected by Mgp Instruments Inc.Licensee Verified,Affected Equipment Has Been Reworked & Tested at Sce.Design Mod Completed 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 ML18065B1351998-01-0606 January 1998 Part 21 Rept Re Use of Deltstrat Code for RCS Flow Rate Determination.Code Corrects for Temps to Determine Hot Leg Bulk Coolant Temp ML20203J2521997-12-0101 December 1997 Deficiency Rept Re Failed Mdr Relays at Entergy Operations Inc,Waterford 3 Nuclear Generation Station.Caused by Contaminated Grease.Housekeeping Procedures Formalized & Added Enclosed Booth Isolating Mdr Final Assembly LD-97-033, Part 21 Rept Re Defect in Potter & Brumfield Mdr Relays, Models 170-1 & 7032.Extended Problem to Include All Mdr Relay Models W/Date Codes 93XX-95XX.Root Cause Analysis, Written Rept & Recommended Corrective Actions Due by 9712011997-11-20020 November 1997 Part 21 Rept Re Defect in Potter & Brumfield Mdr Relays, Models 170-1 & 7032.Extended Problem to Include All Mdr Relay Models W/Date Codes 93XX-95XX.Root Cause Analysis, Written Rept & Recommended Corrective Actions Due by 971201 LD-97-028, Part 21 Rept Re Contamination of Lubricant Which Has Led to Hardening of Lubricant in Certain Potter & Brumfield Mdr Relay Models 170-1 & 7032.Will Distribute Copy of Rept to Utils Having ABB-CE Designed Nuclear Steam Supply Sys1997-10-13013 October 1997 Part 21 Rept Re Contamination of Lubricant Which Has Led to Hardening of Lubricant in Certain Potter & Brumfield Mdr Relay Models 170-1 & 7032.Will Distribute Copy of Rept to Utils Having ABB-CE Designed Nuclear Steam Supply Sys LD-97-024, Part 21 Rept Re Error in Energy Redistribution Factor Used in LOCA Analysis for Listed Plants for Which ABB-CE Performed Analysis.Issued Recommendations Info Bulletin 97-0041997-08-14014 August 1997 Part 21 Rept Re Error in Energy Redistribution Factor Used in LOCA Analysis for Listed Plants for Which ABB-CE Performed Analysis.Issued Recommendations Info Bulletin 97-004 ML20217H0511997-08-0505 August 1997 Part 21 Rept Re Discovery That Radiation Monitoring Sys Power Supply Circuit Board Subject to Premature Electronic Component Failure ML17264A9381997-07-10010 July 1997 Deficiency Rept Re Potential Safety Hazard Associated w/FM-Alco 251 Engin,High Pressure Fuel tube-catalog: 4401031-2 in Which Dual Failure Mode Exists.Caused by Incorrect Forming Process ML20140A9661997-05-29029 May 1997 Part 21 Rept Re Ksv Emergency Diesel Generator Power Piston Failure.Caused by Jacket Water in Combustion Chamber. Recommends That Users Verify That Crown Thickness at Valve Cutout Be 100 Minimum ML20140G4481997-05-0101 May 1997 Part 21 Rept Re Potential Defect in Component of Dsrv & Dsr Enterprise Standby Diesel Generator Sys.Recommends That Springs Be Inspected on Periodic Basis,Such as During Refueling Outages ML17229A2631997-03-12012 March 1997 Part 21 Rept Re Followup of 970307 Event Involving Potential Spring Problem in Bettis Actuator.Recommends That Util Include Two Actuator Replacements of Springs as Precautionary Measures in Next Refurbishment Cycle LD-97-002, Part 21 Rept Re Piping Line Loss Between SG & MSIV Inlet When MSSVs Area Activated.Recommends That Utils Confirm Proper Adjustment of MSSV Blowdown Settings So as to Preclude Valve Chatter & Related Structural Concerns1997-01-17017 January 1997 Part 21 Rept Re Piping Line Loss Between SG & MSIV Inlet When MSSVs Area Activated.Recommends That Utils Confirm Proper Adjustment of MSSV Blowdown Settings So as to Preclude Valve Chatter & Related Structural Concerns ML20133E8001997-01-0808 January 1997 Deficiency Rept Re Nonconformance Related to Masterflow 713 Grout,Which Master Builders,Inc Has Supplied as Nuclear SR Product to 18 Npps.Cause Unknown.Requests That Listed Info Be Provided to Gain Insight as to Scope & Possible Cause ML17229A1631996-11-27027 November 1996 Part 21 Rept Re 2-1878 Globe Piston Check Valves.A/Dv Plans to Include Philosophy of Both Enhancement W/Smaller Piston Check Valves.A/Dv Evaluated Found Condition of Piston Check Valve,Stuck Open ML18065B0111996-10-18018 October 1996 Part 21 Rept Re Application of Certain Aspects of ABB-CE Safety Analysis Methodology ML17229A0571996-09-19019 September 1996 Part 21 Rept Re 2 1878 Piston Check Valve That Failed to Close.Caused by Fretting Wear Damage Between Piston (Disc) & Valvo Body Caused by Pressure Pulsations of Reciprocating Pump ML20117K9731996-09-10010 September 1996 Follow-up Part 21 Rept of Re Failures of Waterford 3 Dedication Testing Process of Seven Commercial Grade Barksdale Pressure Switches ML20116C7031996-07-29029 July 1996 Part 21 Rept Re Failures Identified by Waterford 3 Dedication Testing Process of 7 Commercial Grade Barksdale Pressure Switches ML17229A0101996-07-25025 July 1996 Part 21 Rept Re 2 1878 Stainless Steel,Piston Check Valve Installed in Charging Sys Failed to Close W/Reverse Flow. Performing Evaluation to Determine Cause of Incident.Other Customers Will Be Notified ML20117G4641996-05-14014 May 1996 Part 21 Rept Re Cooper Bessemer Reciprocating Products,Div of Cooper Cameron Corp,Issued Ltr to Define Utils/Plants Containing Similar Equipment as Supplied on Cooper Bessemer Ksv & Enterprise Dsr EDGs LD-96-009, Part 21 Rept Re Potential Instrumentation Decalibr at Low Power.Affected Utils Should Ensure That Log Power Channels Properly Calibr & cross-correlated to Linear Power Channels at 100% Reactor Power1996-04-15015 April 1996 Part 21 Rept Re Potential Instrumentation Decalibr at Low Power.Affected Utils Should Ensure That Log Power Channels Properly Calibr & cross-correlated to Linear Power Channels at 100% Reactor Power ML18065A5001996-02-15015 February 1996 Part 21 Rept Re Hex Bolts Mfg by Cardinal Industrial Products (Cip).Aerofin Will Provide Replacement Bolts for Bolts in Question If Util Notify Aerofin in Writing within 30 Days of Date of ltr.10CFR21 Rept from CIP Encl ML18065A1441995-10-0404 October 1995 Part 21 Rept Re Fastener Products (Hex Bolts) Mfg by Cardinal Industrial Products.Bolts Used as Header Cover Plate Bolts in Safety Related Containment Air Cooler Replacement Cooling Coils Furnished by Aerofin Corp to CPC ML18064A8841995-08-30030 August 1995 Part 21 Rept Re Presence of Hardwired Connection in Each of Four Containment High Pressure Trip Logic Circuits.Jumpers Removed in Slot 11 of Interconnection Module Assemblies in All Four Channels ML20086N9981995-07-21021 July 1995 Part 21 Rept Re Mdr Relays W/Potentially Damaged Internal Contact Arms ML20077D3431994-11-29029 November 1994 Part 21 Rept Re Suspect Master Connecting Rods & Contains Info Location in Engine for Rods ML20078G3051994-11-0909 November 1994 Rev to Part 21 Rept Re Potential Problem W/Master Power Connecting Rods.Vendor Recommends Listed Utils Perform Visual Insp of Master Rods to Determine Applicability of Rept ML18038A8971994-09-0707 September 1994 Part 21 Rept Re Defect in Latching Mechanism of Potter & Brumfield Relay on C&D High Voltage Shut Down Alarm Assembly Printed Circuit Boards.Pull Test on Relay Reset Button Incorporated Into Receiving Insp Procedures LD-94-019, Suppl Part 21 Rept Re Notification of Potential Defect in motor-driven Relays Supplied by ABB-CE to Waterford Steam Electric Station Unit 3.Entergy Oparations Aware of Info1994-03-16016 March 1994 Suppl Part 21 Rept Re Notification of Potential Defect in motor-driven Relays Supplied by ABB-CE to Waterford Steam Electric Station Unit 3.Entergy Oparations Aware of Info LD-93-177, Part 21 Rept Re Potter & Brumfield motor-driven Relays Models 7032,7033 & 7034 Supplied by ABB/C-E to Entergy Operations Waterford Steam Electric Station,Unit 3.Eighty- Two Percent of Affected Relays Tested1993-12-23023 December 1993 Part 21 Rept Re Potter & Brumfield motor-driven Relays Models 7032,7033 & 7034 Supplied by ABB/C-E to Entergy Operations Waterford Steam Electric Station,Unit 3.Eighty- Two Percent of Affected Relays Tested ML20058K3841993-12-0909 December 1993 Part 21 Rept Re Potential Defect in Component of Dsrv & Dsr Enterprise Standby DG Sys,Regarding Potential Problem W/ Subcover Assembled Atop Power Head ML20057G1511993-10-0707 October 1993 Part 21 Rept Re Westronics Model 2100C Series Recorders. Informs That Over Several Tests,Observed That Recorder Would Reset During Peak Acceleration & Door Being Forced Off Recorder.Small Retaining Clips Added to Bottom of Door LD-93-139, Part 21 Rept Re Error in Input to Large Break LOCA Analysis. Paint Thickness Factor of Ten Larger than Intended Used for One of Walls in Containment.Caused by Wrong Value Transcribed & Used in LOCA Analysis1993-09-24024 September 1993 Part 21 Rept Re Error in Input to Large Break LOCA Analysis. Paint Thickness Factor of Ten Larger than Intended Used for One of Walls in Containment.Caused by Wrong Value Transcribed & Used in LOCA Analysis ML20056D7071993-07-15015 July 1993 Part 21 Rept Re Reportable defect-75 PSIG Relief Check Valve 1 Npt,Emd 9521844,Kepner 416C-1-75 ML18058B9021993-07-0101 July 1993 Part 21 Rept Re Potential Defect in Vicor Corp mini-mod Dc/ DC Converter Modules.Deficiency Identified During Failure Analysis of Subj Modules While in Svc at Palisades in Apr 1993.Affected Dc/Dc Converter Modules at Plant Replaced ML20128C3971993-01-28028 January 1993 Suppl to 921217 Final Part 21 Rept Re Defect on Cast Steel Cylinder Heads.One Addl Part (1A-7680) Discovered Which Was Supplied to Util.Copy of Rept Also Sent to Affected Util ML20127H2301993-01-15015 January 1993 Part 21 Rept Re Potential Defeat in Component of Dsrv & Dsr Enterprise Standby DG Sys.Starting Air Distributor Housing Assemblies Installed as Replacement Parts at Listed Sites LD-93-003, Part 21 Rept Re Defect in Potter & Brumfield Model 170-1 Relay.One of Two Rotor Return Springs Broke & Portion of Spring Lodged Between Rotor & Stator.Rotor Springs Supplied by Lewis Spring Co.Info Bulletin Being Prepared1993-01-13013 January 1993 Part 21 Rept Re Defect in Potter & Brumfield Model 170-1 Relay.One of Two Rotor Return Springs Broke & Portion of Spring Lodged Between Rotor & Stator.Rotor Springs Supplied by Lewis Spring Co.Info Bulletin Being Prepared ML20126J5961992-12-31031 December 1992 Part 21 Rept Re Potential Loss of RHR Cooling During Nozzle Dam Removal.Nozzle Dams May Create Trapped Air Column Behind Cold Leg Nozzle Dam.Mod to Nozzle Dams Currently Underway. Ltrs to Affected Utils Encl ML20126B0421992-12-17017 December 1992 Final Part 21 Rept Re Potential Problem W/Steel Cylinder Heads.Initially Reported on 921125.Caused by Inadequate Cast Wall Thickness at 3/4-inch-10 Bolt Hole.Stud at Location Indicated on Encl Sketch Should Be Removed ML20125C7161992-12-0707 December 1992 Part 21 Rept Re Possibility for Malfunction of Declutching Mechanisms in SMB/SB-000 & SMB/SB/SBD-00 Actuators. Malfunction Only Occurs During Seismic Event.Balanced Levers May Be Purchased from Vendor.List of Affected Utils Encl ML20127M5201992-11-24024 November 1992 Final Part 21 Rept Re Reject Lot Serial Numbers of Defective Fuel Nozzle Tips,Consisting of Corrected Page 6 of 921102 Rept Re Reject Lots for Fuel Injector Assembly ML20127P5861992-11-23023 November 1992 Followup to 921005 Part 21 Rept Re Potential Defect in SB/SBD-1 Housing Cover Screws.Procedure Re Replacement of SBD-1 Spring Cover Bolts Encl.All Fasteners Should Be Loosened & Removed.List of Affected Utils Encl 1999-05-05
[Table view] Category:TEXT-SAFETY REPORT
MONTHYEARML18066A6901999-11-0101 November 1999 Rev 5 to Palisades Nuclear Plant Colr. ML20217F2891999-10-13013 October 1999 Drill 99-08 Emergency Preparedness Exercise on 991013 ML17241A4891999-10-0707 October 1999 LER 99-004-00:on 990912,noted That MSSV Surveillance Was Outside of TS Requirements.Caused by Setpoint Drift.Subject MSSVs Are Being Refurbished & Retested Prior to Unit Startup from SL1-16 Refueling Outage.With 991007 Ltr ML17241A4951999-09-30030 September 1999 Monthly Operating Repts for Sept 1999 for St Lucie,Units 1 & 2.With 991014 Ltr ML18066A6761999-09-30030 September 1999 Monthly Operating Rept for Sept 1999 for Palisades Nuclear Plant ML20217G7211999-09-30030 September 1999 Monthly Operating Repts for Sept 1999 for Waterford 3 Ses. with ML20217E3381999-09-30030 September 1999 Monthly Operating Repts for Sept 1999 for Songs,Units 2 & 3 ML20212A1471999-09-13013 September 1999 Special Rept:On 990904,condenser Monitor Was Declared Inoperable.Difficulties Encountered During Component Replacement Precluded SCE from Restoring Monitor to Service within 72 H.Alternate Method of Monitoring Was Established ML20211N0511999-09-0303 September 1999 SER Approving Exemption from Certain Requirements of 10CFR50.44 & 10CFR50 App A,General Design Criterion 41 to Remove Requirements from Hydrogen Control Systems from SONGS Units 2 & 3 Design Basis 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 ML17241A4741999-08-31031 August 1999 Rev 1 to PCM 99016, St Lucie Unit 1,Cycle 16 Colr. ML17241A4591999-08-31031 August 1999 Monthly Operating Repts for Aug 1999 for St Lucie,Units 1 & 2.With 990913 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 ML20211Q2141999-08-31031 August 1999 Monthly Operating Rept for Aug 1999 for Waterord 3 Ses.With ML20211Q8201999-08-31031 August 1999 Monthly Operating Repts for Aug 1999 for Songs,Units 2 & 3. with ML20211H8621999-08-23023 August 1999 Safety Evaluation Accepting Licensee Requests for Relief RR-E-2-03 - RR-E-2-08 from Exam Requirements of Applicable ASME Code,Section Xi,For First Containment ISI Interval 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 ML20210P4731999-08-11011 August 1999 COLR Cycle 10 Songs,Unit 2 ML20210P4791999-08-11011 August 1999 COLR Cycle 10 Songs,Unit 3 ML20210Q6521999-07-31031 July 1999 Monthly Operating Repts for July 1999 for Songs,Units 2 & 3 ML20210S0581999-07-31031 July 1999 Monthly Operating Rept for July 1999 for Waterford 3.With ML20210Q6361999-07-31031 July 1999 Corrected Monthly Operating Rept for July 1999 for Waterford 3 ML18066A6061999-07-31031 July 1999 Monthly Operating Rept for July 1999 for Palisades Nuclear Plant.With 990803 Ltr ML17241A4301999-07-31031 July 1999 Monthly Operating Repts for Jul 1999 for St Lucie Units 1 & 2.With 990805 Ltr ML20210L2771999-07-30030 July 1999 SONGS Unit 3 ISI Summary Rept 2nd Interval,2nd Period Cycle 10 Refueling Outage U3C10 Site Technical Services ML20210D8951999-07-23023 July 1999 Safety Evaluation Accepting First 10-yr Interval Inservice Insp Plan Requests for Relief ISI-018 - ISI-020 ML17241A4111999-07-16016 July 1999 LER 99-007-00:on 990610,unplanned Cooldown Transient Occurred Due to Personnel Error.Trained & Briefed Personnel & Revised Procedures.With 990716 Ltr ML17241A4041999-07-0606 July 1999 LER 99-005-00:on 990604,CEA Drop Resulted in Manual Reactor Trip.Caused by Procedural Inadequacies.Procedure Changes Are Planned to Correct Lack of Procedural Guidance for CEA Subgroup Power Switch Replacement.With 990706 Ltr ML17241A4031999-07-0606 July 1999 LER 99-006-00:on 990605,sub-critical Reactor Trip Occurred Due to Inadvertent MSIV Opening.Caused by Personnel Error. Provided Operation Supervision Instruction to Operating Crews,Stand Down Meetings & Operator Aids.With 990706 Ltr ML18066A5201999-06-30030 June 1999 Monthly Operating Rept for June 1999 for Palisades Nuclear Plant.With 990702 Ltr ML17241A4091999-06-30030 June 1999 Monthly Operating Repts for June 1999 for St Lucie,Units 1 & 2.With 990712 Ltr ML17241A3941999-06-30030 June 1999 LER 99-004-01:on 990415,as Found Cycle 10 Psv Setpoints Were Outside TS Limits.Caused by Manufacturing Process Defect. All Three Psvs Were Replaced with pre-tested Valves During Cycle 11 Refueling Outage.With 990630 Ltr ML17355A3681999-06-30030 June 1999 Revised Update to Topical QA Rept, Dtd June 1999 ML20209H3781999-06-30030 June 1999 Monthly Operating Rept for June 1999 for Waterford 3 Ses. with ML20209C9281999-06-30030 June 1999 Monthly Operating Repts for June 1999 for Songs,Units 2 & 3. with ML20195J8951999-06-17017 June 1999 Safety Evaluation Granting Relief for Listed ISI Parts for Current Interval,Per 10CFR50.55a(g)(5)(iii) ML17241A3551999-06-0404 June 1999 LER 99-002-00:on 990505,both Trains of Safety Injection Actuation Were Blocked During Surveillance.Caused by Procedure Error.Procedure Revised.With 990604 Ltr ML20207E8631999-06-0303 June 1999 Safety Evaluation Accepting Licensee 990114 Submittal of one-time Request for Relief from ASME B&PV Code IST Requirements for Pressure Safety Valves at Plant,Unit 3 ML20195D3061999-06-0202 June 1999 Safety Evaluation of TR SCE-9801-P, Reload Analysis Methodology for San Onofre Nuclear Generating Station,Units 2 & 3. Rept Acceptable ML20195H5491999-05-31031 May 1999 Monthly Operating Rept for May 1999 for Songs,Units 2 & 3 ML20195K3391999-05-31031 May 1999 Monthly Operating Rept for May 1999 for Waterford 3 Ses.With ML18066A4841999-05-31031 May 1999 Monthly Operating Rept for May 1999 for Palisades Nuclear Plant.With 990603 Ltr ML17241A3631999-05-31031 May 1999 Monthly Operating Repts for May 1999 for St Lucie Units 1 & 2.With 990610 Ltr ML20195C3041999-05-28028 May 1999 Annual Rept on Abb CE ECCS Performance Evaluation Models ML17241A3321999-05-17017 May 1999 LER 99-004-00:on 990415,determined That as Found Cycle 10 Psv Setpoints Outside TS Limits.Root Cause Under Investigation.Psvs Replaced with pe-tested Valves During Cycle 11 ML20196L3221999-05-11011 May 1999 SONGS Unit 2 ISI Summary Rept 2nd Interval,2nd Period Cycle-10 Refueling Outage ML17241A3271999-05-0606 May 1999 LER 99-003-00:on 990406,ECCS Suction Header Leak Resulted in Both ECCS Trains Being Inoperable & Entry Into TS 3.0.3. Caused by Chloride Induced OD Stress Corrosion Cracking of Piping.Made Code Repairs & Coated Piping.With 990506 Ltr ML20206H2611999-05-0505 May 1999 Part 21 Rept Re Defect Found in Potter & Brumfield Relays. Sixteen Relays Supplied in Lot 913501 by Vendor as Commercial Grade Items.Caused by Insufficient Contact Pad Welding.Relays Replaced with New Relays ML20206S7401999-04-30030 April 1999 Monthly Operating Rept for Apr 1999 for Waterford 3.With 1999-09-30
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Jl 1111
,.,1111 January 6, 1998 LD-98-001 Document Control Desk U.S. Nuclear Regulatory Commission Washington, DC 20555
Subject:
fofobulletin 97-03, "I;:-iformation Update on the Use of the DELTSTRAT Code for RCS Flow Rate Determination,"
Gentlemen:
As described more fully below, ABB Combustion Engineering (ABB-CE) has issued the subject Infobulletin (attached) to its utility customers, and has recommended that each utility using the DELTSTRAT code evaluate the matters addressed in the Infobulletin for reportability under 10 CFR 21. This report is provided to NRC for informational purposes.
The DEL TSTRAT code is used at several ABB-CE plants (St. Lucie Units 1&2, Waterford Unit 3, San Onofre Nuclear Generating Station Units 2&3, and Palisades) to determine RCS flow rate from data taken with a calorimetric flow measurement technique. The code corrects for temperature stratification effects in the RCS hot legs. A hot leg temperature correction is calculated by the code, and is then applied to the measured hot leg RTD temperatures to determine hot leg bulk coolant temperature. The hot leg bulk coolant temperature, along with other inputs, is then used to calculate the R.CS flo\Y rate.
In several instances, the code overestimated the hot leg temperature correction and produced a calculated flow rate which was substantially larger than expected. A review of test data and the underlying assumptions for the DEL TSTRAT code indicated that improvements in the treatment of certain code inputs could be made which would produce a calculated flow rate that would be closer to the expected value. Infobulletin I l 97-08 discusses ABB-CE's findings and provides recommendations to DELTSTRAT users for assur!ng that the code-calculated RCS flow rates are reasonable and accurate.
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ABB Combustion Engineering Nuclear Operations Combustion Engineering, Inc. P.O. Box 500 Telephone (203) 688-1911 1000 Prospect Hill Road Fax (203) 285-9512 Windsor, Connecticut 06095-0500
LD-98-001 Page 2 ABB-CE has evaluated the matters addressed in the Info bulletin with respect to 10 CFR 21 reportability, and has concluded that insufficient information is available about how individual utilities use the DEL TSTRAT code to determine wh~ther the issue is reportable under 10 CFR 21. Therefore, in addition to the recommendations in the Infobulletin, ABB-CE has recommended that each utility using DEL TSTRAT evaluate whether the issues addressed in the Info bulletin are reportable under 10 CFR 21 in light of how the individual utility uses the code.
Please do not hesitate to call me or George Hess at (860) 285-8405 if there are questions concerning this matter.
I
- ard, Director Operations Licensing
Attachment:
As stated xc: S. Magruder (NRC)
Combustion Engineering lnfobul/etin No. 97-08 Dec. 22, 1997 Information Update on the Use of the DELTSTRA T Code for RCS Flow Rate Determination Summary: The DELTSTRAT code is used at several ABB-CE plants (St. Lucie 1&2, Waterford 3, SONGS 2&3, and Palisades) to determine RCS flow rate from data taken with a calorimetric flow measurement technique. The code corrects for temperature stratification effects in the RCS hot legs. A hot leg temperature correction is calculated by the code, and is then applied to the measured hot leg RTD temperatures in order to determine hot leg bulk coolant temperature. The hot leg bulk coolant temperature, along with other inputs, is then used to calculate the RCS flow rate.
In several applications, for Cycles 9 through 11 at Calvert Cliffs 2, the code overestimated the hot leg temperature correction and produced a calculated flow rate which was substantially larger than expected.
A similar application for Calvert Cliffs Unit 1, Cycle 12 produced an RCS calculated flow rate which appeared to be more reasonable. The overestimation of the RCS flow rate for Unit 2 appears to be related to several factors: 1) unusual temperature trends in some of the hot leg RTD measured temperatures, 2) the impact of a low leakage fuel management scheme with a very peaked core radial power distribution, and 3) isothermal biases for the RTD temperatures.
A review of the Calvert Cliffs test data and the underlying assumptions for the DELTSTRAT code indicated that improvements in the treatment of certain code inputs could be made which would produce a calculated flow rate for Unit 2 that would be closer to the expected value.
This bulletin discusses the findings of the Calvert Cliffs review and provides recommendations to the users for assuring that the DELTSTRAT code calculated RCS flow rates are reasonable and accurate. A listing of all assumptions inherent in the DELTSTRAT code is included here as Attachment #1.
Discussion: There are several assumptions inherent in the formulation of the equations and input for the DELTSTRAT code. One of the assumptions is that the flow mixing factors, which relate how the flows exiting from the core mix with adjoining flows as they proceed into the outlet nozzles and down the hot legs, are invariant with time, power distributions, and relative position of the reactor vessel internals. In the case of Calvert Cliffs 2, for Cycles 9 through 11, the trend of measured hot leg temperatures for channels A and C was unusual. The hot leg temperatures for channels A and C indicated a constant core AT for these cycles even though the expected trend, due to the low leakage fuel management, was an
- *increasing core AT. Chanhel':B and D hot !eg temperatures did show the expected increasing trends with each cycle.
A second assumption used is that the normalized core radial power distribution is an accurate proxy for describing the normalized fuel assembly coolant temperature rise distribution (that is: the ratio of individual assembly to core average coolant temperature rise). This assumption works well for the traditional out-in fuel management schemes used in the earlier fuel cycles for the ABB-CE plants.
However, with the more non-uniform radial power distributions inherent in some of today's low leakage fuel management schemes, a better approach for defining the fuel assembly coolant temperature rise is to use an open-core thermal-hydraulic code, such as the ABB-CE TORC code, along with the actual core radial power distribution. The open-core code will determine the open-core effects of mass, momentum, and energy transfers between adjoining fuel assemblies on the coolant temperature rise in each fuel assembly. The assembly coolant temperature rise data can be normalized in the form of assembly to core average temperature rise factors. The normalized assembly coolant temperature rise factors can then be used as input to the DELTSTRAT code (in place of the core radial power distribution).
The information contained in this Infobulletin is provided by ABB-CE as a service to your organization. Since operation of your plant is completely within your control and responsibility, and involves many factors not within ABB-CE's knowledge, this information may be utilized only with the understanding that ABB-CE makes no warranties or representations, express or implied, including warranties of fitness for a particular purpose or merchantability, with respect to the accuracy, completeness or usefulness of the information contained. ABB-CE disclaims, and you assume, all liability, in negligence or otherwise, as a result of your use of this information.
ABB-CE lnfobulletin No. 97-08 Page 2 of4 Dec. 22, 1997 A third assumption relating to the code inputs involves the measured cold and hot leg coolant temperatures. The measured coolant temperatures are assumed to have any inherent isothermal biases eliminated before being input to the DELTSTRAT code. Removing biases will provide a more accurate set of input to the code and a more consistent picture of the temperature distribution in the RCS piping.
In the Calvert Cliffs Unit 2 situation, it was found that if the Channel A and C temperature data were eliminated, and if open-core exit coolant temperatures were used as input in place of the traditional core radial power factors, the resulting calculated RCS flow rate would be much closer to what was expected.
The reasoning for eliminating the Channel A and C data is as follows:
- 1. The DELTSTRAT code does not have the capability for predicting unusual hot leg temperature trends which may be due to special, localized effects as seen in the case of Calvert Cliffs Unit 2.
- 2. It is suspected that the measured hot leg temperature trend at Calvert Cliffs Unit 2 is real, but local in nature and may not be representative of the overall temperature distribution in the hot leg.
- 3. By using only Channels B and D hot leg temperatures, a more traditional temperature distribution was input to DELSTRAT and a lower calculated RCS flow rate was calculated.
Recommendations:
ABB-CE recommends that the users initiate the following actions in order to assess if there are any current operability problems in determining RCS flow rate in their plant(s) when using the DELTSTRAT code with currently used procedures:
- 1. Review and confirm that the long-term trends (starting from BOC 1) in measured RCS flow rates, as determined with DELTSTRAT, show consistency with any changes in plant hardware on the primary side (i.e., with added SG tube plugging, RCP change-outs, etc.),
within the accuracy of the measurement method.
- 2. Compare current measured RCS flow rates with beginning-of-cycle 1 (BOC 1) values. If today's values are larger than the BOC 1 value by an amount which is greater than the measurement uncertainty, without any corresponding justification from hardware changes*to the primary system, then consideration should be given to reducing the RCS flow rate to the BOC 1value. In the case of the digital plants, the flow rate in the Core Operating Limit Supervisory System (COLSS) and Core Protection Calculators (CPC's) would be reduced.
For the analog plants, the flow rate measured at the beginning of the current cycle would be reduced.
If recommendation 1 or 2 fails, then proceed with recommendation 3 or 4.
- 3. Substitute normalized fuel assembly coolant temperature rise fators, as determined by an open-core thermal-hydraulic computer code, in place of a core radial power distribution when preparing input to the DELSTRAT code, or else:
- 4. Determine a systematic flow bias that will be applied to the flow rate calculated by DELSTRAT with core radial power distribution as input. The flow bias will compensate for the fact that the fuel assembly coolant temperature rise factors are not being used as input.
The infonnation contained in this Infobulletin is provided by ABB-CE as a service to your organization. Since operation of your plant is completely within your control and responsibility, and involves many factors not within ABB-CE's knowledge, this infonnation may be utilized only with the understanding that ABB-CE makes no warranties or representations, express or implied, including warranties of fitness for a particular purpose or merchantability, with respect to the accuracy, completeness or usefulness of the infonnation contained. ABB-CE disclaims, and you assume, all liability, in negligence or otherwise, as a result of your use of this infonnation.
ABB-CE lnfobulletin No. 97-08 Page 3 of4 Dec. 22, 1997 It is recommended that for future cycles isothermal RTD temperature biases be measured at the start of each new cycle for use in correcting measured RTD temperatures prior to being input to DELTSTRAT.
This step is intended to improve accuracy, but is not required to support current operability of the plants.
Applicability: All plants for which the ABB-CE DELTSTRAT code is used to determine RCS flow rate.
Technical Contacts: R. P. Letendre (860) 285-2878 P. F. Joffre (860) 687-8062 Attachment #1 to lnfobulletin No. 97-08 Assumptions used in the DELTSTBA T Methodology
- 1. Eight hot leg and eight cold leg RTD's (from the safety channels) provide input temperature values.
- 2. The average of the cold leg RTD readings in each RCS loop is equal to the bulk cold leg temperature in that loop.
- 3. Hot leg and cold leg isothermal temperature biases are determined and applied to adjust the measured RTD temperatures (individually or collectively).
This js an assumption which the lnfobulletin states is important in obtaining unbiased temperatures for input to DELTSTRAT.
- 4. The flow mixing data from the ABB-CE Palisades flow model tests apply to all ABB CE 2-loop reactor designs. The flow mixing factors are invariant with time, core radial power distribution,*
coolant temperatures, and any unusual localized flow conditions in the hot legs.
This is an assumption which appears to be challenged by the Channel A and C hot leg temperature data trends at Calvert Cliffs Unit 2 during Cycles 9 to 11.
~- --
--5:-- --Th-e-core-radial-powef distribution is a representati'i..e pro~_ for the normalized distribution of fuel assembly coolant temperature rise factors. - - *- - ---- --- - -----~-------
This is an assumption which the lnfobulletin states can be improved upon by using a calculated normalized radial distribution of fuel assembly coolant temperature rise factors as input to DELTSTRAT in place of the radial power distribution.
- 6. Flow mixing in the reactor vessel upper plenum between the two loops is negligible.
The information contained in this Infobulletin is provided by ABB-CE as a service to your organization. Since operation of your plant is completely within your control and responsibility, and involves many factors not within ABB-CE's knowledge, this information may be utilized only with the understanding that ABB-CE makes no warranties or representations, express or implied, including warranties of fitness for a particular purpose or merchantability, with respect to the accuracy, completeness or usefulness of the information contained. ABB-CE disclaims, and you assume, all liability, in negligence or otherwise, as a result of your use of this information.
ABB-CE lnfobulletin No. 97-08 Page 4 of4 Dec. 22, 1997
- 7. Complete mixing of the hot leg coolant temperatures occurs at a distance of 18 hot leg pipe diameters downstream of the reactor vessel outlet nozzle exit. *
- 8. The circumferential distribution of hot leg coolant temperature can be described by a cosine variation.
- 9. The flow in the hot legs may rotate in a solid-body manner as it passes down the length of the hot legs.
- 10. The velocity distribution in the cross-section of the hot legs for Plant X is the same as existed in the Palisades reactor flow model tests, from which the flow mixing factors were determined.
List of recently-issued lnfobulletins:
Number Date Title 97-07, Rev 01 12/31/97 Tech Spec on Azimuthal Tilt in Analog Plants 97-07 10/28/97 Tech Spec on Azimuthal Tilt in Analog Plants 97-06 10/21/97 Core Snubbers I Blocks 97-05 10/21/97 Core Ledge Loads 97-04 7/11/97 Potential Error in the Energy Redistribution Factor Used in LOCA Analysis 97-03 6/5/97 Use of Non-Safety (non-Q) Components in Reactor Protection System 97-02 5/23/97 Spurious Recirculation Actuation Signal 97-01, Supl 1 419197 CESEC Decay Heat Model 97-01 4/3/97 CESEC Decay Heat Model 96-02 4/24/96 Steam Generator Sleeve-to-Tube Weld Indications The information contained in this Infobulletin is provided by ABB-CE as a service to your organization. Since operation of your plant is completely within your control and responsibility, and involves many factors not within ABB-CE's knowledge, this information may be utilized only with the understanding that ABB-CE makes no warranties or representations, express or implied, including warranties of fitness for a particular purpose or merchantability, with respect to the accuracy, completeness or usefulness of the information contained. ABB-CE disclaims, and you assume, all liability, in negligence or otherwise, as a result of your use of this information.