IR 05000282/1981018
| ML20032C195 | |
| Person / Time | |
|---|---|
| Site: | Prairie Island  |
| Issue date: | 10/20/1981 |
| From: | Burgess B, Feierabend C, Little W NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION II) |
| To: | |
| Shared Package | |
| ML20032C194 | List: |
| References | |
| 50-282-81-18, 50-306-81-20, NUDOCS 8111090422 | |
| Download: ML20032C195 (10) | |
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U.S. NUCLEAR REGULATORY COMMISSION
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0FFICE OF INSPECTION AND ENFORCEMENT -
REGION III
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Report No.
50-282/81-18; 50-306/81-20
- Docket No:
50-282; 50-306 License No: DPR-42;:DPR-60 Licensee: Northern States Power Company 414 Nicollet Mall Minneapolis, MN 55401 Facility Name: Prairia Island Nuclear Generating Plant Inspection At:
Prairie I'sland Site, Red Wing, MN 55066-Inspectors:
an&e
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B. L. Burgess
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Approved B);
W.
.L t e, Chief
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Reactor Projects Section 2C
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Inspection Summary.
Inspection on September 1-30, 1981 (Report No. 50-282/81-18: 50-306/81-20)
Areas Inspected: Routine resident inspection of plant operation, maintenance, surveillance, security, radiation protection, Unit I refueling maintenance
.activit es, inservice inspection, reportable events, local leak rate-testing, i
followup on IE circulars and followup on previous inspection findings. The
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inspection involved a total of 173 inspector hours onsite by 2 NRC inspectors
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including 35 inspector hours onsite during of f-shif ts.
f Result s : No items of noncompliance were identified.
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DETAILS 1.
Fersonnel Contacted
- F.
Tierney, Plant Manager
- J. Brokaw, Pisnt Superintendent, Operations and Maintenance
- E. Watzl, Plant Superintcndent, Plant Engineering and Radiation Protection
- D. Mendele, Superintendent Operations Engineering
- A.
Hunstad, Staf f Engineer D. Schuelkg Superintendent Radiation Protection R. Lindsey, Superintendent Operations R. Stenroos, Assistant Radiation Protection Superintendent J. Nelson, Superintendent, Maintenance J. Hof fman, Superintendent, Technical Engineering M. Klee, Superintendent, Nucleat Engineering A.. Smith, Senior Scheduling Engineer J. Curtis, Engineer D. Brown, Engineer D. Haugland, Engineer B. Frazer, Engineer G. Lenertz, Engineer M. Gruber, Engineer G. Miller, Engineer T. Thomas, Engineer D. Hansen, Inservice Inspection Engineer B. Stephens, Engineer K. Beadell, Engineer D. Cragoe, Shif t Supervisor P. Ryan, Shif t Supervisor M. Balk, Shift Supervisor T. Goetsch, Shif t Supervisor J. Meath, Shif t Supervisor D. Walker, Shif t Supervisor P. Valtakis, Shif t Supervisor R. Held, Shift Supervisor
- Denotes those attending the exit interview.
2.
Licensee Action on Previous Inspection Findings a.
(Closed)
Noncompliance (50-282/81-08: 50-306/81-09)
Related to failure to record as found value for instrument calibra-tion. The inspector confirmed that the licensee's Section Work In-struction was revised on July 31, 1981 and that it has been imple-mented.
b.
(Closed) Noncompliance (50-282/81-11; 50-306/81-13)
Related to escort of visitors. Corrective actionJ described in the licensee's response were verified.
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3.
Operations Safety Verification a.
General Unit I returned to power on September 1,1981, af ter recovering from the trip that occurred on August 31.
The Unit I refueling outage was delayed one week until September 19 to allow Unit 2 to retern to power before shutdown of Unit 1.
Unit 2 was shut down September 3 through September 13 to repair a stean generator tube leak. The unit has been operating at power for the rest of the month.
b.
Control Room Observations The inspector observed control room operations, reviewed applicable logs, conducted discussions with control room operators and observed shift turnovers. The inspector verified the operability of selected emergency systems, reviewed equipment control records and verified proper return to service of affected components.
During supervisory review of the operating log on September 28, the licensee determined that the operators had missed a requirement to run the No.121 motor driven fire pump on the previous day. The test was to demonstrata operability daily because the No. 122 diesel driven fire pump was out of service. The No. 121 pump had already been successfully deconstrated operable on the 28th. The inspector observed that operating shif t personnel were admonished to assure that all operability testing is performed as scheduled.
c.
Tours Tours of the auxiliary, turbine, and' containment buildings and ex-ternal areas were conducted to observe plant equipmem conditions, including potential fire hazards, and to verify that maintenance work requests had been initiated for equipment in need of maintenance.
The inspectors made several tours of Unit 2 containment in conjunction with No. 22 steam generator tube leak repair and replacement cf rod con-trol cluster K7 rod position indication stack and cables. Unit 1 con-tainment entries were made to observe progress of maintenance activities and preparations for refueling.
d.
Independent Verification The inspector performed a walkdown of the accessible portions of the Cooling Water and Residual Heat Removal Systems. Observations in-cluded confirmation of selected portions of the licensee's procedures, checklists, plant drawings, verification of correct valve and power supply breaker positions to insure that plant equipment and instru-mentation are properly aligned, and review of control room and local system indication to insure proper operations within prescribed limits.
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4.
Unit 2 No. 22 Steam Generator Tube Leak Indication of a tube leak of about 0.1 gpm was obgrved on August 26, 1981, as noted in a previous inspection report.- On Septembet 3 there was an increase in the leak rate to 0.3 gpm.
The licensee elect-ed to shutdown for repair so that the unit would be back on line before the scheduled Unit I refueling outage.
The inspectors observed portions of.the operation and maintenance activ-ities related to shutdown. preparation for access to_the steam genera-
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tors, and return of systems to operable status af ter. repairs.
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Review of inspection data and discussion with inservice inspection (ISI)
personnel confirmed that the leak was from a tube that should have been plugged during the previous refueling outage. The tube was one that was severely degraded in the areas of the gtivibration bars, (AVB), as des-cribed in the licensees' event report.- It was apparent that the tube to be plugged had not been carrectly identified on the hot leg side of the tube sheet, as inspection showed that an adjacent good tube was plugged, rather than the defective tube. The licensee conducted eddy currant testing of the failed tube and all tJjacent tubes. The tests confirmed additional degradation at all AVB's in the leaking tube and confirmed that the adj tubes were not degraded. The licensee will amend the event reportg ent s
to describe the additional inspection and repair.
The licensee completed repairs and the generator was back on line on
~h September 13, 1981.
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5.
Surveillance The inspectors *iitnessed portion of surveillance testing of safety re-lated system and components. The inspection included verifying that the tests were scheduled and performed within Technical Specification require-ments, observing that procedures were being followed by qualified opera-tors, that LCO's were not violated, that system and equipment restoration was completed, and that test results were acceptable to test and Techni-cal Specification requirements.
Tests witnessed included:
a.
SP-1093 Diesel Generator Manual and 4KV Voltage Rejectfon/ Rester-ation Scheme Test.
Test was satisfactory.
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b.
SP-1100 Motor Driven Auxiliary Feedwater Pump Test.
Test was satisfactory, f_1 IE Inspection Report No. 50-282/81-li 50-306/81-19
/2 LER P-RO-81-02, Tube Degradation in Steam Generators, dated March 13, 1981
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c.
S P-1047.
Control Rod Exercise, Unit 1 Control rod bank C rod insertion limit moniter (RILM) was found failed during the performance of the test.
~A work request was issued-and.the bank C RILM repaired. After repair the instrument was returned to service (discussed in paragraph 12.a of this report) and the bank C RILM ~
portion of the test completed to prove operability.
d.
'SP-1003 Analog Protection Functional Test, Unit 1
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During the performance of the surveillance a pressurizer
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low pressure bistable would not trip. After completion
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of the remainder of the test satisfactorily, a work request authorization (WRA) was issued. The bistable was found to have a failed cipacitor, and the bistable was replaced and tested satisfactorily. The licensee intends to issue an event report.
e.
SP-1033 Response to Safeguards Signal Test, Unit 1
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The 1 test is performed coincident with a loss of offsite
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power signal to test the starting, bus stripping, r.ad loading sequence of the diesel generators. All systems performed as designed and the test was completed satis-
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factoriiy. Three valves in separam systems were identi-
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fled as not being fully functional, but were able to meet
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. ainitaum sy$. tem performance requirements.
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The test results were reviewed by tht system engineer and the,0perations Committee as acceptable. The valves that
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were' identified as needing maintenance during the test had work requests issued for repair. The inspector will folicw the licensee's repair of the valves.
't. SP-1049 Main Steam Safety Valve Test, Unit 1 Test vas performed during Unit 1 shutdown for refueling,
The test involved using a hydroset to actuate the safety
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valve by adjusting hydroset pressure to the safety valves lifting pressure.
Loop B manifold steam safety valve RS-21-8 did not lift when tested at setpoint pressure and could not be actuated when the hydroset was brought to maximum preseure. The valve will he removed and bench tested to determine lift-ing pressure. After repair the valve will be reinstalled and hot tested prior to Unit I return to power operation.
The licensee intends to issue an event report.
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6.
Maintenance a.
Review of Work Request (WR's) and Work Fequest Authorizatb n (WRA's)
The inspectors selected and reviewed several WR's and WRA's to deter-mine the status of safety related systems, to verify that proper pric-ities were given and to verify that design changes were initi-ated where appropriate.
b.
Obse rvations The inspectors observed portions of safety related maintenance activ-ities to determine that the activities did not violate limiting con-ditions for operations (LCO's), that administrative approvals and equipment control tags were completed prior to initiating the work, that approved procedures were used (or activity was within the
" skills of the trade"), that the procedures used were adequate to control the activity, ard that proper QA/QC controls were used.
(1) The inspector observed portions of the repair of a Unit 2 rod position indication instrument. The rod position instrument (RPI) for rod control cluster K7 had failed during a Unit 2 startup. The RPI instrument was declared inoperable and Tech-nical Specifications reviewed for applicability. During Unit 2 shutdown to find and fix the No. 22 steam generator leakage, the decision was made to also repair the inoperable RPI instru-
"t ment. Both the cable and the RPI stack were replaced, tested and calibrated prior to returning the instrument to service.
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Operation of the RPI instrument during Unit 2 return to power operation was within Technical Specification requirements.
(2) The inspectors observed the preparation nd restoration of plant systems and equipment during the repair of No. 22 steam generator tube leak. Observations included a review of pro-
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cedures and comparison with actual equipment status to insure
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procedural and Technical Specification compliance.
7.
-Inservice Inspection of Steam Generators
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Eddy current examination of Unit 1 No.11 steam generator tubes during the refueling cutage identified degraded and defective tubes. This re-quired expansion of the inspection to include all of the tubes in the
' (No.11 steam generator and to increase the sample size for the No.12
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steam generator. Eddy current testing is still in progress.
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8.
g ortable Events
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The licensee identified the following items as reportable in accordance
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with Technical Specification requirements.
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Bistable Failure, Unit 1 Pressurizer Low Pressure Reactor Trip
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(Paragraph 5.d)
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b.
Axial Flux Dif ference Deviation From Target Band, Unit 1 At approximately 0530 on September 12, an operator noted that the axial flux indication was slightly above the allowable 57, deviation from the target flux. He t ook immediate action to reduce the de-viation by inserting control rods. A review of the computer log indicated thet the target band had been exceeded for 31 minutes.
The flux deviation was indicated to be plus 2.894 compared to a target flux of minus 2.3% which had been established on August 12.
This placed the allowable deviation at plus 2.7%.
Surveillance Test SP-1135 was completed on September 14, establishing the new target flux dif ference at plus 1.437. which would allow the flux
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deviation to be between minus 3.57% and plus 6.43% Operation at a deviation of plus 2.89% was well within the new target band, so significance of the event is minimal.
c.
Rags Found in Loop Seal Piping to Pressurizer Safety Valve Inlet During preparation for replacement of Unit 1 pressurizer safety valves with tested spares the licensee found that the loop seni in-let piping had not drained. Personnel were in the process of re-moving the water from the piping when they found some rags at the bottom of the loop seal, obstructing the 3/4 inch drain piping.
The licensee removed the rags from the piping and have retained them for further examination and evaluation. Af ter confirming that the piping was clear for both safety valves, the tested valves were installed.
The licensee immediately informed the resident inspector and notified RIII by telecopy. The inspector participated in examination of the rags. The rags were inside a fairly heavy plastic bag for contamin-ation control. One rag appeared to be burlap and another a light-weight cotton print materic1.
The licensee is continuing to investigate possible source and time that the rags had entered the loop seal piping. The condition of the rags indicate that they had been in the piping for a long time, very pcssibly since contruction of the plant. The licensee has re-quested assistance from the architect engineer and a test laboratory to deternine what affect the rags may have on operability of the safety valve. Verbal information received indicated that the rags would not prevent the valve from relieving pressure, and would prob-ably desintegrate from the high velocity steam relieving at set-point pressure.
The resident inspection staff will continue to monitor the licensee's followup actions. This item remains unresolved.
(282/81-18-01)
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One Loop B. Main Steam Safety Valve Failed to Open During Test (See Paragraph 5. f)
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c.
No. 22 Diesel Cooling Water Pump Operability On September 25, an operator observed that the No. 22 diesel cool-ing water pump switch green light was not lit. The operator deter-mined that the pump was inoperable, consequently an operability test of the No. 12 pump and the D1 diesel generator war completed in accordance with Technical Specification requirements.
Investi-gation by the station electrician found a loose wire in the control cabinet. Af ter correcting the problem the pump was demonstrated to be operable, f.
Instrument Drif t, Unit 2 Steam Pressure Transmitter Scheduled surveillance testing in September identified a steam pressure transmitter drift exceeding allowable limits. The drift was identified to be caused by a gain potentiometer. The poten-tiometer was replaced and the component calibrated successfully.
The licensee plans to report in accordance with Technical Specifi-cation requirements.
g.
Tube Degradation in Unit 1 Steam Generators (See Paragraph 7)
9.
Injured Workman On September 29, 1981, while working in support of maintenance being performed in the Unit 1 turbine building, a wcrkman received an elec-trical shock from a magnaflux machine that had been brought into the plant to inspect secondary system piping and compotents. The workman was immediately attended by the plant nurse and transported to che hos-pital for observation. When the licensee doctor recommended that ob-servation be continued for more than 48 hours5.555556e-4 days <br />0.0133 hours <br />7.936508e-5 weeks <br />1.8264e-5 months <br /> the licensee notified the NRC via the red phone in accordance with 10 CFR 50.72.
Tha licensee industrict safety personnel are investigating the cause and means for preventing recurrence. Preliminary information indicates that a problem existed in the powar connection to the magnaflux machine.
10.
Local Leak Rate Testing (LLRT)
The inspector observed portions of LLRT of containment isolation valves during the Unit 2 outage. Observations included verifying that the tests were performed using approved procedures, that test equipment was calibrated, and that test personnel were qualified. For those valves that were found to exceed their individual leakage requirements, the inspector insure that work requests were issued for repair, that a d
retest was scheduled, and they will be included in the licensee's integrated leakage report.
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11.
IE Circulars The inspector verified that the licensee had received IE Circulars (IEC's) and had taken actions to review for applicability and imple-mentation where required.
a.
IEC No. 80-16 Operational Deficiencies in Rosemount Model 510 DU Trip Units and Model 1152 Pressure Transmitters.
The licensee reviewed the circular and determined that none of the components identified in the circular are used or planned for use in the plant.
(Closed.)
b.
IEC No. 81-06 Potential Deficiency Affecting Certain Foxboro 10 to 50 Mil 11 ampere Transmitters.
The licensee has addressed the potential in con-junction with environmental qualification in response to IEB 79-01B.
(Closed.)
c.
IEC No. 81-12 Inadequate Periodic Test Procedure of PWR Pro-tection System.
The licensee reviewed the circular and determined that the relay logic installed is not similar to that described in the circular.
(Closed.)
12.
Documenting Operability Testing Technical Specifications '(TS) define operability, and specify operability requirements for system and components. The TS allow certain systems or components to be inopersole or degraded for limited periods of time, but in most cases require that operability of other or redundant components be verified prior to removal of a component from service and/or period-ically while the system is degraded.
The question of documentatb n of verification of operability was dis-cussed with licensee personnel in conjunction with two occasions where the TS require actions to be taken when a component was inoperable.
a.
Rod Insertion Limit Monitor On Sep ember 8 a control rod exercise test noted a problem with the control bank C rod insertion limit monitor. A work request was issued and repairs completed the same day. The Unit 1 operation log did indicate removal from service and return to service. There was no log entry nor indication in the work request that operability was demonstrated prior to or after return to service. At the in-spector's request, the monitor was demonstrated to be operable later the same day.
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b.
Screen Wash Pump On September 22, the No.122 diesel driven fire pump was taken out of service while the intake bay was drained for circulating water pump maintenance. With this pump out of service TS requires a daily 15 minute operability test of the No.121 motor driven fire pump and the No. 121 screen wash pump. This was considered when approving the work request authorization for the work, and noted that " normal operation of the screen wash pump fulfills this re-quirement" as the pump operates on a timer, running 45 minutes every 4 hours4.62963e-5 days <br />0.00111 hours <br />6.613757e-6 weeks <br />1.522e-6 months <br />. Normally this could be checked by computer log when the pump motor starts, however, after the computer was re-moved from service on September 25 there was no record of screen wash pump operation.
In neither case was there any indication that the component was in-cperable, but the record did not document operability testing. This was discussed with appropriate management personnel and at the exit interview. The inspectors will review licensee actions to improve documentation of operability testing.
13.
Unresolved Items Unresolved items are matters about which more information is required in order to ascertain whether they are acceptable items, items of non-compliance, or deviations. One unresolved item was identified during the inspection as discussed in Paragraph 8.c.
Exit Interviews The inspectors conducted interim interviews and conducted an ayfe 3t-ing at the conclusion of the inspection with those plant personnel des-ignated by an asterisk in Paragraph 1.
The inspectors discussed the scope and results of the inspection. The if ensee confirmed the status of steam generator tube inspection and the status cf investigation of the rags found in the loop seal piping.
The licensee stated that the prel'minary information received from their requests for evaluation indicated that safety valve operability would not have been affected. The licensee stated that the evaluation may indicate that a prompt report is not required. The licensee con-firmed that whether the event is considered reportabla or not, a follow-up letter descrf5ing the event and evaluation would be forwarded promptly.
The licensee also confirmed that the main steam safety valve that did not lift during hydroset test would be rested cold to determine the
"as found" setpoint.
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