05000285/LER-1991-001, :on 910109,determined That Containment Tendon Surveillances Performed in 1981 & 1985 Did Not Reflect Guidance in Tech Specs.Caused by Inadequate Administrative Controls.Testing Program Plan Implemented
:on 910109,determined That Containment Tendon Surveillances Performed in 1981 & 1985 Did Not Reflect Guidance in Tech Specs.Caused by Inadequate Administrative Controls.Testing Program Plan Implemented
05000285/LER-1999-002, :on 980910,inadvertent Ventilation Isolation Actuation Signal Occurred While Maint Was Being Performed. Caused by Switch Failure.Key Switch for RM-062 Has Been Replaced.With
05000285/LER-1999-002, :on 980910,inadvertent Ventilation Isolation Actuation Signal Occurred While Maint Was Being Performed. Caused by Switch Failure.Key Switch for RM-062 Has Been Replaced.With
ML20216E636
ML20210D995
ML20210G218
ML20210R196
ML20216E643
LIC-99-0084, Monthly Operating Rept for Aug 1999 for Fort Calhoun Station.With
ML20211J932
LIC-99-0096, Monthly Operating Rept for Sept 1999 for Fcs,Unit 1.With
Omaha Public Power District 444 South 16th Street Mall Omaha, Nebraska 68102-2247 402/636-2000 l
February 8, 1991 LIC-91-0008L V. S. Nuclear Regulatory Commission Attn Document Control Desk Mail Station P1-137 Washing'.an, DC 20555 Reference: Docket No. 50-285 Gentlemen:
Subject:
Licensee Event Report 91-01 for the Fort Calhoun Station l
Please find attached Licensee Event Report 91-01 dated February 8, 1991. This I
LICENSEE EVENT REPORT (LER) gu4gigo,AgNgty Tg,Tgt F APE RWO Rt T ON J
3 504 0 IC 08 MANActutNT AND Dd004T.W ASMINGTON. 0c gesca ed.CILITV NAMG HI DoCEtT seVMet A GI PAGE i3i Fort Calhoun Station Unit No. 1 o i s I o I o l 0 l218 15 1 lod 014 flTLS les Containment Tendon' Surveillance Determined Not In Accordance With Tech. Specifications tytNT DAf t til LER hvMSIRtel ASPORY DAf t til DTH8 R 7 ACILIIlt$ INVOLytO ($l MONTw OAy Vlam vtAR 88,0M ',
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- On January 9, 1991, with the reactor-in Mode 1 at approximately 26% power, it was determined that prior to the performance of the containment tendon surveillances c
l in~1981 and 1985, the test procedures were changed to reflect the guidance of L
By using guidance not reflected incorporates the guidance in Revision 1 af Regulatory Guide 1.35, is more-l in the Technical Specifications, both these tests failed to completely detension all the required tendons.
This violation of the Technical Specification is reportablepursuantto10CFR50.73(a)(2)(i)(B).
l The root cause for this event was inadequate administrative control of the tendon I,
surveillance program, with inappropriate actions by personnel as a contributing factor.
Corrective actions include: enhancement of station en implementation of a Containment Testing Program Plan;gineering support, including improvements in the safety evaluation process for procedure changes; and submittal of a proposed license amendment to incorporate appropriate Regulatory Guide 1.35, Revision 3 guidance into the Technical Specifications.
Mit.','e"JJi*fs'u?t,c"N Ei'e?'J E', t'.?di 08 MANAGlutNT AND SVDGtt.* A$HINGTON. DC 20603 F AClkttY NAME II)
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t The containment structure at Fort Calhoun Station Unit No. 1 is a ' reinforced concrete pressure vessel that includes ungrouted prestressing tendons in the domed roof and the walls.
These tendons are stressed to keep the containment concrete internalforces(i.e.,anincreaseincontainmentpressure)gnitudesuchthattheintroduced b in compression. The compressive. forces are of sufficient ma basis accident will be offset by the containment prestressing. This will result in an essentially stress-free containment building during the event.
Tnere are 210 dome tendons and 616 helical wall tendons in the containment structure. The idome tendons are divided into three layers that are mutually inclined at 120 degrees. The wall tendons consist of four layers arranged in a 45 degree helical-3attern-in two directions,--i.e., two right-handed helical and two left-handed 1elical layers.
Each orientation is considered to be a group.
NuclearRegulatoryCommission(NRC)RegulatoryGuide1.35,"InserviceInspection of Ungrouted Tendons =in Prestressed Concrete Containments, Revision 1", dated June
.1974, specified that a tendon liftoff test should include an unloading cycle going
'down-to essentially complete detensioning of the tendon to identify broken or.
damaged wires or strands.
It also stated that for. containments that differ from the typical, the model program. described should serve as a basis for a com) arable inservice inspection program.
The Fort Calhoun containment differs from tie
, typical model.due to the use of the helical wall tendons.
InAugust1974,OmahaPublicPowerDistrict(0 PPD)submittedaFacilityLicense i
Change to the NRC to in' corporate the guidance provided.by Regulatory Guide 1.35, Revision 1, into the Fort Calhoun Technical Specifications.
In August 1975, the requirement for comp btely detensioning each selected tendon was incorporated into the Technical Specifications by License Amendment No. 6.
The 1976 tendon testing.
was completed to this specification.
Technical Specification 3.5(7)a requires that periodic inspections be performed on three dome-tendons, one from each layer, and on three wall tendons of each orientation.
The surveillance requirements for each tendon selected include taking of lift-off readings,. complete.detensioning, and examination for broken l
wires and for any evidence of damage or deterioration of anchor hardware.
.-Additionally, the Specification requires the removal of one wire from each of three-helical tendons and one from.a dome tendon for inspection and testing. This is accomplished after fully detensioning the selected tendons. Following the
- surveillance, each detensioned tendon-is fully retensioned to at least the average wire stress indicated by the last liftoff reading for that tendon.
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.a - unc w, am,mn In April 1979, the NRC issued for comment Revision 3 of Regulatory Guide 1.35.
This revision proposed the requirement to detension all sample tendons be relaxed to detensin just one tendon per group. The value and im)act section noted that detensioning all the surveillance tendons to look for broien wires "is quite marginal and the cost is high." Revision 3 of Regulatory Guide 1.35 was approved and issued in July 1990.
1 On January 9, 1991, with the reactor in Mode 1 at approximately 26% power, a nonconformance in the tendon surveillance testing program was identified by the Special Services Engineer in charge of the Containment Tendon Testing Program.
It was found that prior to the performance of the tendon surveillance in 1981, the
_ test procedure was changed to reflect the guidance of the proposed Revision 3 of Regulatory Guide 1.35 without having an approved corresponding change incorporated into Technical Specification 3.5(7). The 1985 test was also performed usir.g the guidance in Regulatory Guide 1.35, Revision 3.
By using guidance not reflected in the Technical Specifications, both these tests failed to completely (detension all therequiredtendonsasrequiredbyTechnicalSpecification3.5(7)ai).
This violation of the Technical Specification is reportable pursuant to 10 CFR 50.73(a)(2)(1)(B).
An operability evaluation was subsequently aerformed by Station Engineering. This I
evaluation confirmed that, although the Tec1nical S)ecification requirement to detension all selected tendons was not fulfilled, tie operability of the tendons and the containment structure was not compromised.
Investigation revealed that the engineers assigned to coordinate the 1981 and 1985 surveillances apparently did not realize that Fort Calhoun Station was committed to Revision 1 of Regulatory Guido 1.35 by License Amendment No. 6.
A procedure change to the surveillance test prior to the performance of the 1981 test revised the test to ref'a t the guidance in Revision 3 of the Regulatory Guide.
Prior to the performance of the 1985 test another 3rocedure change was made to incorporate l
the guidance of a vendor procedure into t1e test procedure.
The vendor procedure stated that it satisfied the requirements of Revision 3 of Regulatory Guide 1.35.
Both these procedures changes were approved by the Plant Review Committee.
The root cause for this event was inadequate administrative control of the tendon surveillanco program, with inappropriate actions by personnel as a contributing factor.
Inexperienced engineers were assigned to coordinate the tendon surveillance tests in 1981 and 1985, and they initiated did not fully comply with the Technical Specifications. procedure changes which There was poor turnover of information between the test engineers.
Inadequate review by management, including the Plant Review Committee, allowed approval of changes to the test procedures such that the tests did not meet all the requirements of the Technical Specifications.
TJ.W saa Fort Calhoun Station Unit No.1 o l5 lo lo lo i 2l 8l5 9l 1 0 l0 l 1 010 014 oF 0 l4 ftXT (# more asese e revuroef, use aduguenst MC Form asBCs/ 07)
The results of the tendon testing indicate that the containment prestressing system is not degraded by the failure to detension all the surveillance tendons in the 1981 and 1985 surveillance tests.
Detensioning of tendons is not required to to inspect for degraded wires or anchor hardware.
Since this examination was adequately performed during the performance of the liftoff portion of the surveillance and no problems were found, the operability of the containment prestressing system was never compromised. The surveillance methods used met the guidelines of Regulatory Guide 1.35, Revision 3 which has been approved by the NRC.
It is concluded that there is no safety significance associated with this event.
The following corrective actions have been completed:
(1)
Anoperabilityevaluation(PED-SSE-91-0032, Revision 1 dated January 16, 1991) and root cause analysis were performed by the Special Services Engineer in charge of the Containment Tendon Testing Program.
(2)
The OPPD program for generation and review of nuclear safety evaluations associated with procedure changes has been improved in recent years. This will assure compliance with regulatory guidance.
(3)
Station engineering support has been enhanced with additional personnel and administrative controls. A Programs Development Project was initiated to establish program plans which insure quality, regulatory compliance, and continuity for infrequent tests such as tendon surveillance. The Technical-Specification noncompliance noted in this report was identified during the preparation of the Containment Tendon Testing program plan by the Program-Engineer.
l l
The following corrective actions will be completed:
e (1)
A Facility License Change will be submitted to incorporate ap3ropriate guidance provided by Regulatory Guide 1.35, Revision 3 into t1e Technical
' Specifications. This change will be submitted by June 30, 1991.
(2)
The Containment Testing Program Plan and Basis Document will be completed and issued prior to performance of the next scheduled tendon surveillance.
Therehavebeen-4additionalLER's(87-10,87-37,88-08,and89-02)dealingwith surveillance tests-that did not meet the r"uirements of the Technical Specifications.
on 910109,determined That Containment Tendon Surveillances Performed in 1981 & 1985 Did Not Reflect Guidance in Tech Specs.Caused by Inadequate Administrative Controls.Testing Program Plan Implemented
on 901209,ventilation Isolation Actuation Signal Generated by High Alarm on Process Radiation Monitor RM-062.Caused by Accumulation of Noncondensible Gases in Sample Piping.Valve Packing Leak Repaired
on 910212,offsite Power Low Signal Outside Design Basis.Caused by Inadequate Mod Design at Time of Performance of Original Degraded Voltage Analysis. Engineering Analysis EA-FC-91-017 Performed
on 910228,steam Generator Pressure Indicator B/PIC-905 Declared Inoperable Due Reading Approx 56 Psig Lower than Normal.Caused by Misinterpretation of Affected Ts.Formal Interpretation Will Be Written
on 910305,fire Detection Zone 6 Alarmed in Control Room & Could Not Be Reset.Caused by Inadequate Administrative Control to Assure Mod to XL-3 Panel Properly Reflected in Procedures.Personnel Trained
on 910320,480 Volt Circuit Breaker Coordination Outside Design Basis.Caused by Deficiencies in Original Sys Design.Breaker/Fuse Coordination Study to Be Completed & Problems Will Be Corrected
Revises Completion Dates for Corrective Actions to Address LER 91-08 Re Inappropriate Surveillance Requirements for RPS Level I Bistables & LER 91-11 Re Pressurizer Pressure Low Signal Setpoints to 921120 & 1231,respectively
on 910517,determined That Auxiliary Steam Piping in Upper Electrical Penetration Room 27 Outside Design Basis.Caused by Lack of Attention to Detail During Initial Drawing Review.Fire Dampers Closed
on 910606,mgt Determined Potential Existed for Pressurizer Pressure Instrument Loops to Be Calibrated in Manner Resulting in Inability to Trip Pressurizer Pressure Low Signal within Limits
on 910620,emergency Diesel Generator Auto Start Occurred Due to Loss of Transformer.Caused by Personnel Error.Relays Labelled for Proper Identification
on 910626,diesel Generator DG-2 Autostarted During Performance of Surveillance Test,Resulting in Tripping & Locking Out Breaker 1AD1.Caused by Human Error. Event Discussed W/Licensed Operator
on 910629,radiation Monitor RM-054A Discovered Out of Svc.Caused by Personnel Error.Test OP-ST-SHIFT-0001 Revised to Include check-off When All Radiation Monitors Calibrated
on 910710,personnel Declared Radiation Monitor RM-060 Inoperable Due to Flow Totalizer,Located Inside Monitor Cabinet,Not Seismically Mounted.Caused by Inadequacies in Design Process
on 910711,roll Pin for Diesel Generator Exhaust Damper Linkage Failed.On 910718,crack Discovered in Roll Pin for DG-1 Linkage.On 910802,util Notified That Crack Due to Mfg Defect.Also Reported Per Part 21
on 910819,potential for Radiological Release Through Safety Injection Refueling Water Tank Vents Identified as Result of Evaluations Prompted by Similar Industry Events
on on 910911,0314,0701,0912 & 900311,side Wall Cracks Discovered in Cells of Station Batteries.Caused by Inadequate Design of Battery Cell Terminal Post Seals. Batteries Replaced
on 910913,approved Procedure Specified Incorrect Position for Valves in Backup Nitorgen Sys.Caused by Inadequate Preparation & Review of 10CFR50.59 SE W/ Procedure Revs.Revised Procedure OI-NG-1
on 910919,SG Water Containing Approx 2.25 Lbs of Hydrazine Inadvertently Released to Missouri River.Caused by Failure of Procedure OI-FW-6 to Specify Proper Sequence for Performance of Valve Checklist
on 911004,inadvertent Partial Actuation of Containment Isolation Actuation Sys Occurred.Caused by Improper Switch Contact Stackup.Caution Tag Placed on Switch Until Corrective Actions Completed
on on 911009,evaluation Initiated in Response to 910912 Neutron Flux Channel Concerns,Per Rev 2 to Reg Guide 1.97.Caused by Failure to Follow Procedure PED-QP-5. Memo Issued.Also Reported Per Part 21
on 911022,emergency Response Facilities Computer Sys Taken off-line for Maint Activities & Power Increased to 99.3%.Caused by Failure to Review Appropriate Tech Specs.Precaution Added to Procedure
on 911106,ventilation Isolation Actuation Signal Received When Electrician Removed Wrong Fuse Block from Control Panel.Caused by Personnel Error.Standing Order Revised Re Pulling Fuses or Lifting Leads
on 911114,determined That Upset & Faulted Loadings on Two Safety Injection Sys Pipe Supports Exceeded Design Capacity of Embedded Unistrut.Caused by Design Deficiency.Piping Supports Modified
on 911105,discovered That Senior Reactor Operator Did Not Have Current NRC Medical Exam.Caused by Lack of Single Point Control of NRC Medical Exam Program. Personnel Training Info Sys Upgraded
Between 911016-1118,abnormal Increases Noted in Reactor Coolant Drain Tank Level.Caused by Opening Test Valve WD-1060 During Sampling.Standing Orders Reviewed & Label Developed for Locked Closed Valves
on 911201,discovered That Sample Pump for Lab & Radwaste Processing Bldg Exhaust Stack Gas & Iodine Monitors Not Running.Caused by Power Excursion Due to Severe Winter Weather.Design Change Under Review
on 911202,deficiency Discovered in Personnel Air Lock Leak Rate Testing & Procedure.Caused by Past Inadequate Procedure Change Reviews.All Type B Leak Rate Test Procedures Will Be Reviewed
on 911210,containment Pressure Reduction Not Terminated When Radiation Monitor RM-060 Removed from Svc. Caused by Breakdown in Written & Verbal Communication & Work Practices.Procedures Revised
on 911216,determined That Connections to Personnel Air Lock Bulkheads for Leak Testing Potentially Outside Original Design Requirements.Caused by Lack of Procedures.Danger Tags Hung on Door