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Category:NRC TECHNICAL REPORT
MONTHYEARML20203C0021998-02-0505 February 1998 NRC Assessment Rept Fifteenth Year Tendon Surveillance Virgil C Summer Unit 1 ML20238A6961987-09-0202 September 1987 LER Quality Evaluation for Summer During Period Jan 1986 - Jul 1987 ML20137X6671986-01-16016 January 1986 AEOD/E602, Unexpected Criticality Due to Incorrect Calculation & Failure to Follow Procedures, Engineering Evaluation Rept 1998-02-05
[Table view] Category:TEXT-SAFETY REPORT
MONTHYEARML20217D6401999-10-31031 October 1999 Rev 2 to WCAP-15102, VC Summer Unit 1 Heatup & Cooldown Limit Curves for Normal Operation RC-99-0202, Monthly Operating Rept for Sept 1999 for VC Summer Nuclear Station.With1999-09-30030 September 1999 Monthly Operating Rept for Sept 1999 for VC Summer Nuclear Station.With ML20216J4191999-09-24024 September 1999 Part 21 Rept Re 990806 Abb K-Line Breaker Defect After Repair.Vendor Notified of Shunt Trip Wiring Problem & Agreed to Modify Procedure for Refurbishment of Breakers RC-99-0180, Special Rept on 990807,electric Driven Fire Pump XPP0134A Was Declared Inoperable.Caused by Pump Discharge Relief Valve Failing to Open as Normally Expected.Two Temporary Fire Pumps Were Installed to Provide Backup Suppression1999-09-0808 September 1999 Special Rept on 990807,electric Driven Fire Pump XPP0134A Was Declared Inoperable.Caused by Pump Discharge Relief Valve Failing to Open as Normally Expected.Two Temporary Fire Pumps Were Installed to Provide Backup Suppression RC-99-0183, Monthly Operating Rept for Aug 1999 for Virgil C Summer Nuclear Station,Unit 1.With1999-08-31031 August 1999 Monthly Operating Rept for Aug 1999 for Virgil C Summer Nuclear Station,Unit 1.With ML20211K6161999-08-31031 August 1999 Rev 2 to VC Summer Nuclear Station,Colr for Cycle 12, Dtd Aug 1999 RC-99-0168, Special Rept:On 990804,electric Driven Fire Pump XPP0134A & Diesel Driven Fire Pump XPP0134B,were Removed from Svc to Allow for Plant Mod.Fire Pumps Were Returned to Operable Condition on 990818,after Mod Was Completed1999-08-19019 August 1999 Special Rept:On 990804,electric Driven Fire Pump XPP0134A & Diesel Driven Fire Pump XPP0134B,were Removed from Svc to Allow for Plant Mod.Fire Pumps Were Returned to Operable Condition on 990818,after Mod Was Completed ML20210M7071999-07-31031 July 1999 Rev 1 to VC Summer Nuclear Station COLR for Cycle 12 ML20211C2201999-07-31031 July 1999 Rev 1 to WCAP-15102, VC Summer Unit 1 Heatup & Cooldown Limit Curves for Normal Operation RC-99-0163, Monthly Operating Rept for July 1999 for VC Summer Nuclear Station,Unit 1.With1999-07-31031 July 1999 Monthly Operating Rept for July 1999 for VC Summer Nuclear Station,Unit 1.With RC-99-0137, Monthly Operating Rept for June 1999 for VC Summer Nuclear Station,Unit 1.With1999-06-30030 June 1999 Monthly Operating Rept for June 1999 for VC Summer Nuclear Station,Unit 1.With RC-99-0122, Monthly Operating Rept for May 1999 for VC Summer Nuclear Station.With1999-05-31031 May 1999 Monthly Operating Rept for May 1999 for VC Summer Nuclear Station.With ML20206H2971999-05-0505 May 1999 Part 21 Rept Re Common Mode Failure for magne-blast Breakers.Vc Summer Nuclear Station Utilizes These Breakers in Many Applications,Including 7.2-kV EDG Electrical Buses RC-99-0103, Monthly Operating Rept for Apr 1999 for VC Summer Nuclear Station.With1999-04-30030 April 1999 Monthly Operating Rept for Apr 1999 for VC Summer Nuclear Station.With ML20206K2421999-04-30030 April 1999 Rev 0 to COLR for Cycle 12 for Summer Nuclear Station RC-99-0087, Part 21 Interim Rept (SSH 99-0001) Re 990218 Failure of Circuit Breaker Located in Cubicle 14 of XSW1DB to Close During Surveillance Testing.Caused by Positive Interlock Angle Was Incorrect.Breaker Was Returned to GE Factory1999-04-15015 April 1999 Part 21 Interim Rept (SSH 99-0001) Re 990218 Failure of Circuit Breaker Located in Cubicle 14 of XSW1DB to Close During Surveillance Testing.Caused by Positive Interlock Angle Was Incorrect.Breaker Was Returned to GE Factory RC-99-0083, Monthly Operating Rept for Mar 1999 for VC Summer Nuclear Station,Unit 1.With1999-03-31031 March 1999 Monthly Operating Rept for Mar 1999 for VC Summer Nuclear Station,Unit 1.With RC-99-0063, Special Rept:On 990302 & 16,meteorological Site Number One 10 Meter Temp Element Was Declared Inoperable.Caused by Erratic Operation.Cabling & 10 Meter Electrical Connectors Were Replaced1999-03-26026 March 1999 Special Rept:On 990302 & 16,meteorological Site Number One 10 Meter Temp Element Was Declared Inoperable.Caused by Erratic Operation.Cabling & 10 Meter Electrical Connectors Were Replaced ML20196K5421999-03-22022 March 1999 Rev 2 to VC Summer Nuclear Station,Training Simulator Quadrennial Certification Rept,1996-99, Books 1 & 2. Page 2 of 2 Section 2.4.4 (Rev 2) of Incoming Submittal Were Not Included RC-99-0055, Special Rept:On 990302,Meteorological Site Number One 10 Meter Temp Element (RTD) Was Declared Inoperable Due to Erratic Operation.Cause of Original RTD Failure Is Unknown. Equipment Was Declared Operable on 9903121999-03-16016 March 1999 Special Rept:On 990302,Meteorological Site Number One 10 Meter Temp Element (RTD) Was Declared Inoperable Due to Erratic Operation.Cause of Original RTD Failure Is Unknown. Equipment Was Declared Operable on 990312 RC-99-0050, Monthly Operating Rept for Feb 1999 for VC Summer Nuclear Station,Units 1.With1999-02-28028 February 1999 Monthly Operating Rept for Feb 1999 for VC Summer Nuclear Station,Units 1.With ML18106B0931999-02-25025 February 1999 Part 21 Rept Re Possible Defect in Swagelok Pipe Fitting Tee,Part Number SS-6-T.Caused by Crack Due to Improper Location of Heated Bar.Only One Part Out of 7396 Pieces in Forging Lot Was Found to Be Cracked.Affected Util,Notified ML20203F4511999-02-12012 February 1999 SER Finding Licensee Adequately Addressed GL 96-05, Periodic Verification of Design-Basis Capability of Safety-Related Motor-Operated Valves, for Virgil C Summer Nuclear Station ML18106B0551999-02-0101 February 1999 Part 21 Rept Re Possible Matl Defect in Swagelok Pipe Fitting Tee,Part Number SS-6-T.Defect Is Crack in Center of Forging.Analysis of Part Is Continuing & Further Details Will Be Provided IAW Ncr Timetables.Drawing of Part,Encl ML18106B0441999-01-29029 January 1999 Part 21 Rept Re Possible Defect in Swagelok Pipe Fitting Tee Part Number SS-6-T.Caused by Crack in Center of Forging. Continuing Analysis of Part & Will Provide Details in Acoordance with NRC Timetables ML20206R5241998-12-31031 December 1998 Santee Cooper 1998 Annual Rept RC-99-0052, Vsns 1998 Annual Operating Rept. with1998-12-31031 December 1998 Vsns 1998 Annual Operating Rept. with RC-99-0004, Monthly Operating Rept for Dec 1998 for VC Summer Nuclear Station,Unit 1.With1998-12-31031 December 1998 Monthly Operating Rept for Dec 1998 for VC Summer Nuclear Station,Unit 1.With ML20206R5191998-12-31031 December 1998 Scana Corp 1998 Annual Rept ML20198F4241998-12-18018 December 1998 Safety Evaluation Granting Relief Request for Approval to Repair ASME Code Class 3 Service Water Piping Flaws in Accordance with GL 90-05 for VC Summer Nuclear Station RC-98-0223, Special Rept 98-001:on 981130,steam Line High Range Gamma Monitor (RMG-19C) Was Declared Inoperable Due to Indeterminate Alarm.Caused by Failures in Detector & Meter Reset Circuitry.Established Preplanned Alternate Method1998-12-16016 December 1998 Special Rept 98-001:on 981130,steam Line High Range Gamma Monitor (RMG-19C) Was Declared Inoperable Due to Indeterminate Alarm.Caused by Failures in Detector & Meter Reset Circuitry.Established Preplanned Alternate Method RC-98-0222, Monthly Operating Rept for Nov 1998 for VC Summer Nuclear Station,Unit 1.With1998-11-30030 November 1998 Monthly Operating Rept for Nov 1998 for VC Summer Nuclear Station,Unit 1.With ML20155G4551998-11-0404 November 1998 Safety Evaluation Accepting Licensee Proposed Alternative to Use Code Case N-416-1 with Licensee Proposed Addl Exams RC-98-0208, Monthly Operating Rept for Oct 1998 for VC Summer Nuclear Station,Unit 1.With1998-10-31031 October 1998 Monthly Operating Rept for Oct 1998 for VC Summer Nuclear Station,Unit 1.With ML20207J5701998-10-31031 October 1998 Non-proprietary Rev 1 to WCAP-14955, Probabilistic & Economic Evaluation of Rv Closure Head Penetration Integrity for VC Summer Nuclear Plant ML20154Q9571998-10-21021 October 1998 SER Accepting Request Seeking Approval to Use Alternative Rules of ASME Code Case N-498-1 for Class 1,2 or 3 Sys ML20154K7901998-09-30030 September 1998 Non-proprietary Rev 0 to WCAP-15101, Analysis of Capsule W from Sceg VC Summer Unit 1 Rv Radiation Surveillance Program RC-98-0184, Monthly Operating Rept for Sept 1998 for VC Summer Nuclear Station.With1998-09-30030 September 1998 Monthly Operating Rept for Sept 1998 for VC Summer Nuclear Station.With ML20154K8041998-09-30030 September 1998 Non-proprietary Rev 0 to WCAP-15103, Evaluation of Pressurized Thermal Shock for VC Summer Unit 1 RC-98-0166, Monthly Operating Rept for Aug 1998 for VC Summer Nuclear Station,Unit 1.With1998-08-31031 August 1998 Monthly Operating Rept for Aug 1998 for VC Summer Nuclear Station,Unit 1.With ML20237A7181998-08-13013 August 1998 SER Accepting Util Response to GL 95-07, Pressure Locking & Thermal Binding of Safety-Related Power-Operated Gate Valves RC-98-0153, Monthly Operating Rept for July 1998 for VC Summer Nuclear Station,Unit 11998-07-31031 July 1998 Monthly Operating Rept for July 1998 for VC Summer Nuclear Station,Unit 1 RC-98-0131, Monthly Operating Rept for June 1998 for VC Summer Nuclear Station1998-06-30030 June 1998 Monthly Operating Rept for June 1998 for VC Summer Nuclear Station ML20248J0191998-06-0404 June 1998 Safety Evaluation Accepting Licensee Inservice Testing Program Interim Pump Relief Request Per 10CFR50.55a(a)(3) (II) RC-98-0113, Monthly Operating Rept for May 1998 for VC Summer Nuclear Station,Unit 11998-05-31031 May 1998 Monthly Operating Rept for May 1998 for VC Summer Nuclear Station,Unit 1 RC-98-0100, Monthly Operating Rept for Apr 1998 for VC Summer Nuclear Station,Unit 11998-04-30030 April 1998 Monthly Operating Rept for Apr 1998 for VC Summer Nuclear Station,Unit 1 ML20217G7411998-04-22022 April 1998 Rev 1 to VC Summer Nuclear Station COLR for Cycle 11 RC-98-0076, Final Part 21 Rept Re a DG EG-B for Vsns,As Followup to .Power Control Svcs of Engine Sys,Inc Provided Response on 980318.Evaluation Concludes That Failure of EG-B Is one-time non-repeatable Failure1998-04-17017 April 1998 Final Part 21 Rept Re a DG EG-B for Vsns,As Followup to .Power Control Svcs of Engine Sys,Inc Provided Response on 980318.Evaluation Concludes That Failure of EG-B Is one-time non-repeatable Failure RC-98-0084, Monthly Operating Rept for Mar 1998 for Virgil C Summer Nuclear Station,Unit 11998-03-31031 March 1998 Monthly Operating Rept for Mar 1998 for Virgil C Summer Nuclear Station,Unit 1 ML20212H1421998-03-0202 March 1998 Interim Part 21 Rept SSH 98-002 Re EG-B Unit That Was Sent to Power Control Svcs for Determination of Instability & Refurbishment of a Dg.Cause of Speed Oscillations Unknown. Completed Hot Bore Checks on Power Case 1999-09-08
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NRC Asseusment Report Fifteenth Year Tendon Surveillance Virgil C. Summer Unit 1
- 1. INTRODUCTION Title 10 Part 50 of the Code of Federal Regulations. Appendix A General Design Criterion 53(2) requires the licensee to have a periodic containmet structure surveillance program. At the NRC's request, South Carolina Electric and Gas Company (SCE&G, the licensee) submitted a V. C. Summer Unit 1 containment building 15 year physical tendon surveillance report ta the NRC on l August 8, 1996. The licensee performed the surveillance in accordance with V.
l C. Summer Nuclear Station's Technical Specification (TS), SCE&G Specification SP 228 044461 000 Rev. 10 Proposed Rev. 3 to Regulatory Guide (RG) 1.35, and the Precision Surveillance Corporation Surveillance Manual, Both the TS and the RG specify performing periodic tendon surveillance as follows:
. inspecting tendon sheathing filler material
. measuring tendon lift off force
. inspecting anchorage components e
inspecting tendon wires and performing tensile testing
. checking grease leakage e detensioning and retensioning tendons
) . refilling and resealing grease caps The surveillance involved nine tendons (three from each tendon group, i.e.,
dome, vertical and horizontal) that the licensee selected randomly.
The licensee cor.cluded that the post-tensioning system, as a whole, is in a satisfactory condition, based on an analysis of the surveillance results. The NRC r0 guested the licensee to submit the report for NRC review to assure that tendon system performance is as desigiied. After a careful review of the report, the NRC had reservations about the licensee's test procedure and method of analyzing the tendon lift-off test data. The NRC conveyed its concerns to the licensee in two Requests for Additional Information (RAls),
e Enclosure
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2 The licensee's October 28, 1997 RAI response included a tendon surveillance data re analysis. Re analysis results indicated that the dome and hoop tendons will go below the minimum required value about 32 years after performing the structural integrity test (SIT). The licensee concluded that the V. C. Summer Nuclear Power P'it does not have any abnormal containment building post tensicning system agradation, based on the information obtained from the 15 year tendon e.. veillance.
- 2. EVALUATIfd The NRC staff reviewed the licensee's report, and found that the results of the 15 year post tensioning system tendon surveillance generally conform with the relevant TS anri Regulatory Guide 1.35. Proposed Revision 3. acceptance criteria. However. dfter a careful examination of the licensee's tendon tests and its analysis._the staff had some reservations about the licensee's test procedure and analysis method. A discussion of this, and our conclusions, follow.
2.1 Tendon Lift Off Force The-licensee did not detension and retension the tendons as specified in Sections 4.2 and 7.2 of RG 1.35. Proposed Rev. 3. even though they claimed to have done this, Section 4.2 requires that during retensioning. the simultaneous measurement of elongation and jacking force should be made_ at a minimum of three approximately equally spaced levels of force between zero and lock off force, it appears that during installation, the licensee recorded ,
only the seating force and its corresponding elongation, and did the same l
during the retensioning, disregarding Section 4.2 recommendations. The '
purpose of Sect m ' 2 is to check how well the lift off was done. If the information specified by Section 4.2 is available, the linear relationship 4 between force and elongation can be used for such a check. Section 7.2 specifies recording elongation corresponding to a specific load during detensioning and retensjoring. and then comparing this with values obtained during the initial tendon installation. The purpose of Section 7.2 is to ensure that the difference between the elongations at detension and at initial installation is not related to wire failures or a slippage of wires in the anchorage. With the button head system used, the latter is not likely.
- However, the potential for wire failure exists. Section 7.2 specifies that the licensee should identify any difference of more than 10% in their tendon surveillance report. From the tendon retensioning data which the licensee provided in its October 28, 1997, response, the difference for one tendon (D220) was 20.48% and the difference for the other (V69) was 12.8%. The licensee did not identify any wire failures in their report, nor did they
i 3-provide a reason for the differences. Without the information specified in Section 4.2, it becomes difficult to determine the source of the differences.
One plausible explanation is that there was an error in making the measurements.
The license used the average of the lift off forces for each surveillance and plotted this on a graph to determine the trend of t > 'estressing forces for each group of tendons. There we five points on the v 5 to represent the _
five surveillances. The five point > are joined by line segments. On the !
basis of such a graph, the licensee determined visually that the tendon force {
1evel will be acceptable beyond the 20th year, i.e., the next surveillance for l each group of tendons. Such a method of forecasting the tendon forces is too i simplistic and lacks a good theoretical basis. The staff requested the licensee to perform a linear regression analysis using the individual lift off forces from each surveillance instead of-the average of the lift-off forces.
The licensee performed this analysis, and found that the hoop and dome tendons will not go below the minimum required force until approximately 32 years after performing the SIT. For the vertical tendons which have been retensioned, the time that they are predicted to go below the minimum required force is 42 years after performing the SIT. Therefore, there should not be any concern with respect to the level of tendon forces before the next surveillance.
2.2 Grease Voids Table XIII of the licensee's physical tendon surveillance report indicates that there is barely any tendon grease leakage. However for one vertical tendon (V-40) the grease replaced is 10.75 gallons less than that removed.
The licensee attributed this shortfall to an error in the recorded amount of grease removed. A subsequent licensee evaluation determined that the difference was actually only 1.5 gallons. Chemical tests of the greare as shown in Table 1 of the licensee's report fully met the acceptance criteria.
The licensee removed wires from the detensioned tendons and found them to be
'either in excellent or good condition i.e., no corrosion or barely any. No water was found either in the grease can or around the anchorages.
2.3 Anchorage Assembly and Tendon Wire The licensee inspected the button heads of the wires. The only abnormalities found were three broken or missing button heads. Anchor-heads, bushings, shims and end bearing plates were also visually examined.for cracking and corrosion..and only some minor corrosion and pitting were found. The licensee took wire samples in accordance with its specified procedure, and subjected
...o
. 4 them to tensile testing. The tests revealed there was no significant change in ultimate strength. The licensee also examined the concrete around the bearing plates, and no cracks greater than 0.010 inch were evident. On the basis of the information provided, the staff concludes that anchorage components and the tendon wire are in good condition.
3.0 CONCLUS10N-On the basis of the staff's review of the information provided by the licensee, the staff concurs with the licensee's conclusion that the overall condition of the containment tendon system is satisfactory. However, we l
recommend that the licensee follow the guidance in Section 4.2 of RG. 1.35, 1 Rev. 3, for future tendon surveillance. This will provide a method for-determining how well they perform the surveillance. It_also can be used to trace the source of any errors -in the tendon lift-off tests without much i additional effort. Further, in determining the trend of the tendon forces of i
a group through the use of linear regression analysis, the individual tendon i
forces in the group, not their average, should be used._ The licensee's 20-year surveillance results might indicate that the hoop and dome tendon forces will go below the minimum required values prior to the 32nd year after the structural integrity test. The licensee should have a long_ term plan for this. The licensee has indicated that prior to the next (sixth) tendon surveillance, the tendon surveillance program will be updated to comply with 10 CFR 50.5Sa. which requires licensees to incorporate ASME Section XI Subsections IWE and IWL into their_ Inservice Inspection Program.
Principal Contributor: C, P. Tan Date: February 5, 1998 S w