IR 05000282/1988001
| ML20147C712 | |
| Person / Time | |
|---|---|
| Site: | Prairie Island  |
| Issue date: | 02/25/1988 |
| From: | Defayette R NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION III) |
| To: | |
| Shared Package | |
| ML20147C692 | List: |
| References | |
| 50-282-88-01, 50-282-88-1, 50-306-88-01, 50-306-88-1, NUDOCS 8803030143 | |
| Download: ML20147C712 (10) | |
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NUCLEAR: REGULATORY COMMISSION'-
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REGION III
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Reports No. 50-282/88001(DRP); 50-306/88001(DRP)=
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Docket Nos.:50-282; 50 306 Licenses No? DPR-42; DPR-60-Licensee:
Northern StatesfPower Company-414 Nicollet Mall
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Minneapolis, MN 55401 Facility Name:
Prairie Island Nuclear Generating Plant, Units 1 and 2 Inspection At:
Prairie Island Site, Red Wing, Minnesota Inspection Conducted: January 3 through February 13, 1988 Inspectors:
J. E. Hard
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M. M. Moster Approved By:
R. DeFayette, Chief
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'I Reactor Projects Section 28 Date'
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Inspection Summary
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Inspection on January 3 through February 13, 1988 (Reports No. 50-282/88001(DRP); No. 50-306/88001(DRP))
Areas Inspected:
Routine, unannounced inspection by resident inspectors of previous inspection findings, plant operational safety, maintenance,
surveillances ESF systems, refueling outage activities, LER followup, emergency planning, training, and meetings with corporate management.
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Results:
Of the nine areas inspected, no violations or deviations were identified.
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DETAILS r
1.
Persons Contacted
- R. Jensen. Senior Vice President, Power Supply
- C, Larson, Vice President,-Nuclear Generation
- L. Eliason, General Manager, Nuclear Plants
'P. Kamman, Superintendent, Nuclear Operations Quality Assurance
- E. Watzl, Plant Manager
- D.;Mendele, General. Superintendent, Engineering and Radiation Protection R. Lindsey, Assistant to the. Plant Manager
- M. Sellman, General Superintendent, Operations D. Schuelke,. Superintendent, Radiation Protection G. Lenertz, General Superintendent,-Maintenance
- K. Beadell, Superintendent, Technical Engineering
- H. Klee, Superintendent, Quality Engineering R. Conklin, Supervisor, Security and Services D._ Vincent, Project Manager, Nuclear Engineering and Construction J. Goldsmith, Superintendent, Nuclear Technical Services
- A. Hunstad, Staff Engineer
- S. Hiedeman, System Engineer
- T. Amundson, Superintendent Training
- A. Smith, General Superintendent, Planning and Services A. Vukmir, Site Services Representative, Westinghouse Electric Corp.
D. Dilanni, License Project Manager, NRR C. Sundstrom, Cygna Energy Services S. Masciulli, Cygna Energy Services The inspectors interviewed other licensee employees, including members of the technical and engineering staffs, shift supervisors, reactor and auxiliary operators, QA personnel, Shift Technical Advisors, and Shift Managers.
- Denotes those present at the exit interview of February 16, 1988.
- Denotes NSP personnel who visited Region III on January 7, 1988.
2.
Licensee Action On Previous Inspection Findings (92701)
(Closed) Violation 282/87011-01:
No. 11 Safety Injection (SI) Pump Was Found To Be Inoperable For Approximately 27 Days.
Cause of this event was the failure to leave the No. 11 SI pump 4 KV breaker completely racked in.
All other 4 KV breakers were checked and found to be properly racked in.
The SI breaker was inspected mechanically and electrically and found to be in proper working order.
Administrative controls were tightened and included a requirement that any safety-related 4 KV breaker be operationally tested after being racked in.
In addition, procedure changes were implemented which provides better control of the status of the SI pump motor breakers as well as improved methods for independent verification.
All operators have received hands-on training on these revised procedures.
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(Withdrawn) Violation 282/87012-03:
No. 10 Bank Tran'sformer In The Substation Was Disabled As A Result Of Relay Crew Failing To Follow t
Procedures.
This personnel error caused the No. I reserve transformer to lockout, disabling all cooling tower fans, No. 21 cooling water pump, and the Unit No. 1 operating charging pump.
In addition, safety systems also responded (i.e., No. 1 and No. 2 emergency diesel generators and the No.12 diesel driven cooling water pump autostarted). As noted in Section 8 of this report, the corrective actions undertaken as a result of this and similar events will be tracked under Open Item 282/88001-02(DRP).
3.
Operational Safety Verification (71707)
Unit 1 was base loac'ad at 100% power except for rer'uctions for surveillance testing.
U,it 2 cc menced a refueling outage January 6, 1988 and was placed on lina on February 13, 1988.
The inspector observed control room operations, reviewed applicable logs, conducted discussions with control room operators, and observed shift turnovers.
The inspector verified operability of selected emergency systems, reviewed equipment control records, and verified the proper return to service of affected components.
Tours of the auxiliary building, turbine building and external areas of the plant were conducted to observe plant equipment conditions, including potential fire hazards, and to verify that maintenance work requests had been initiated for equipment in need of maintenance.
D2 Diesel Generator Lockout - Following a successful surveillance test of 02 at the start of the Unit 2 refueling outage and with D2 shut down, an unexpected alarm was received which indicated a diesel lockout because of low pressure lobe oil.
This unexpected lockout, which would have prevented restart of the diesel for two minutes (except with a safety injection (SI) signal) was the result of the very low air temperature in the diesel generator room at the time of the test (outside air temperature was - 20 degrees F).
This low temperature inhibited the rate of pressure decay in the oil pressure sensing line, thus generating the untimely lockout signal.
Corrective actions being taken to prevent recurrence include changing the oil in the sensing line to lighter weight oil (already accomplished) and covering the floor grating near the sensing line to prevent outside air from directly contacting the line (work request prepared).
No violations or deviations were identified.
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4.
Maintenance Observation (62703)
c Routine, preventive, and corrective maintenance activities (on safety-related systems and components) were observed / reviewed to ascertain that they were conducted in accordance with approved procedures, regulatory guides, and industry codes or standards, and in conformance with Technical Specifications.
The following. items were considered during this review:
the limiting conditions for operation were met while components or systems were-removed from' service, approvals were obtained prior to initiating the work, activities were accomplished using approved procedures and were inspected as applicable, functional testing and/or calibrations were performed prior to returning components
.or systems to service, quality control records were maintained, activities were accomplished by qualified personnel, radiological controls were implemented, and fire prevention controls were implemented.
See Section-7 for details of the Unit 2 refueling outage maintenance activities that were observed.
No violations or deviations were identified.
5.
Surveillance (61726)
The inspector witnessed portions of surveillance testing of safety related systems and components.
The inspection included verifying that the tests'
were scheduled and performed within Technical Specification requirements,.
observing that procedures were-being followed by qualified operators, that Limiting Conditions for Operation (LCOs) were not violated, that system and equipment restoration was completed, and that test results were acceptable to test and Technical Specification requirements.
Portions of the following surveillances were observed / reviewed during the inspection period:
SP 1093 Emergency Diesel Generator No. 1 Surveillance
SP 2035 Unit 2 Reactor. Protection Logic Test
SP 2018 Unit 2 Reactor Protection Instrumentation Hot Calibration
SP 2136 Maintenance Airlock Test
SP 2070 Reactor Coolant System Integrity Test No violations or deviations were identified.
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ESF System Walkdown-(71710)
The inspector performed a complete walkdown of_the accessible portions of-Unit 1 and Unit 2 emergency diesel generators.
0bservations included 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 instrumentation are properly aligned, and-local system indication to insure proper operation within prescribed limits.
No violations or devia' tions were identified.
7.
Unit 2 Refueling Outage Activities (60710, 61715)
The following are brief summaries of special areas inspected during the inspection period:
Condensate storage tank (CST) level transmitters - The level sensing system for CST 21 and 22 froze at'the start of the outage.
The causes of freezing were poor choice of sensing line routing plus materials stored against the lines which insulated them from the warm buildir.g air.
The lines have been rerouted.
Source range detectors - On shutdown of Unit 2, neither detector responded to the neutron flux when high voltage was automatically restored.
Both detectors required replacement.
New annunciator windows - B Panel in the control room was replaced with one which was modified in accordance with a human factors review.
However, the new annunciator windows on B Panel prepared in accordance with NRC guidelines, were engraved with letters and numbers which are smaller and more difficult to read than with the previous windows.
The operations group will be eva',uating window acceptability during the current operating run.
Manual tripping of residual heat removal (RHR) pump - On January 15, 1988 with the reactor water level near nozzle centerline and with the steam generators open for tube testing, power was accidentally lost to the RHR flow controllers because the control circuit was switched off by error.
RHR flow from the operating pump increased from 1000 gpm to 3500 gpm as the flow control valve went to its fully open fail safe position.
After a few minutes of operation in this mode, operators turned off the pump to prevent vortexing (no vortexing was experienced nor did pump venting show that any significant amount of air had been drawn into the RHR system.)
Power was promptly restored to the flow controllers and an RHR pump restarted. Core exit thermocouples indicated an increase of about 12 degrees F as a result of the flow disruption of about six minutes.
The cause of this event appears to have been an incorrect electrical schematic or wiring diagram.
This event and other recent examples of incorrect wiring diagrams (work on condensate storage tank level indicators causing AFW pump alarms, fuel manipulator crane, and NIS cable containment penetrations) call into question the accuracy of electrical drawings.
The licensee is investigating the matter.
This is an Open Item (50-2Cu88001-01; 50-306/88001-01(ORP)).
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ESF accumulator nozzle crack - During post-shutdown inspection of the Unit 2 reactor coolant system, a pinhole leak in the lower level tap nozzle for the number 22 accumulator was detected from the bulldup of boric acid crystals on the nozzle.
The main cause of the leak appears to have been inappropriate fitup of the level sensing pipe in the nozzle during construction which resulted in sufficient stress in the fully sensitized austenitic nozzle to induce stress corrosion cracking.
The nozzle was replaced with a new one.
Non-destructive tests of the other Unit 2 accumulator nozzles yielded acceptable results.
For Unit 1, which is currently in operation at full power, visual inspections are to be conducted at least every 30 days until the next outage at which time ultrasonic and dye penetrant testing will be performed.
(See also Inspection Report 50-306/88003(DRS)).
Instrument air line failure - Failure of an improperly assembled Graylock fitting inside containment caused a partial loss of instrument air.
The air systems for both units are being walked down to look for such potential problems.
Limitorque valve operator testing - Work required by IE Bulletin No. 85-03 on safety-related motor-operated valves (M0Vs) was completed during the outage.
During the testing one valve failed to open on command with maximum differential pressure across it.
This was the cooling water emergency supply valve to the number 11 auxiliary feedwater pump.
Adjustments to the Limitorque operator corrected the difficulty.
The valve could have been opened at any time using the manual handwheel had the need to do so arisen.
A report of the testing results is to be prepared and submitted as required by the Bulletin.
Feedwater (FW) pipe thinning measurements - The first comprehensive post-Surry-event ultrasonic (UT) measurements were completed.
Approximately 50 areas in the piping both upstream and downstream of the FW pumps were examined.
A small area of 16-inch diameter schedule 100 piping downstream of the number 21 FW pump yielded thickness measurements which were less than code allowable.
This section of piping, about 14 inches long, was removed for visual examination which showed insignificant erosion but which revealed laminations in the pipe wall which had been in existence since the original pipe fabrication.
This defective section was replaced.
Another small area of piping near the FW pumps was shown to require replacement after the resident inspector questioned certain UT data points.
This area was in the 20-inch Schedule 20 condensate piping upstream of the FW pumps.
A section in this area was removed and visual examination made of the pipe interior.
No evidence of corrosion or erosion was seen.
The licensee concludes that the thin wall probably existed since plant construction days.
A 20-foot section of the questioned piping was replaced.
Unit No. 2 steam generator eddy current inspections during this refueling outage resulted in two tubes in No. 21 steam generator being plugged (total of 59 are now plugged (1.7%)), and three tubes in No. 22 steam generator being plugged (total of 130 are now plugged (3.8%)).
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Circulating water bellows - The large diameter circulating water (condenser cooling) piping in the turbine building contains steel-reinforced elastomer bellows.
Routine inspection of these bellows showed deterioration serious enough to require replacement of two of them.
Installation of a control system to automatically shut down the circulating water system in the event of failure in this piping (including the bellows) has been under review and is to be done.
Breaker 23M problems - 23M is a 480 v. breaker serving non-safety related loads.
After rack-in following maintenance and testing work, the breaker failed to operate properly.
An inspection was performed which confirmed that there were no mechanical problems, suggesting that the problem might be in the racking procedure.
The breaker was reinstalled and the racking and closing procedure witnessed by the inspector.
The licensee and inspector agreed that the procedure was difficult to follow and needed to be rewritten, and that more plant training was required on breakers of this design.
In view of this and previous problems with breaker racking, a training tape is to be prepared which will describe and discuss all the different breaker types found in the plant.
In-core thimble tube wear - All 36 in-core thimble tubes were replaced during the outage of September-October 1986.
Ultrasonic testing of these tubes during the January-February 1988 outage revealed measurable wear on most of the tubes in the top support plate region.
The wall thickness of the worst of the tubes had been reduced by 40%.
Several others indicated wear in the 20-30% range. The tube indicating 40% wear was capped.
All tubes are to be retested during the next outage.
The licensee stated that from past experience and from data taken at other Westinghouse-designed plants, the rate of wear decreases rapidly with time.
Instrument column leak - During reactor coolant system (RCS) heatup at the end of the outage, a steam leak was seen on one of the instrument columns on the reactor vessel head. The source of leakage was noted to be a pitted canopy seal weld at the top of the tube.
The seal weld was removed, the area underneath cleaned, and a new design seal ring successfully installed.
Observations during startup - The inspectors observed the approach to criticality, the placing of the main generator on line, and part of the ascension to full power.
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Physics test data obtained at zero power was in very good agreement with predicted data except that core leakage as indicated by A and B rod bank worths was less than expected, b.
Indicated and actual reactor power tracked very closely (within about 10%) during the power ascension, particularly at greater than 10% of rated.
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Station auxiliary transformer disconnects - The low side (4160v.)
disconnects to the 2M transformer were found to be open a few hours after the main generator was placed on line.
The plant startup procedure requires a verification that these disconnects be closed prior to main generator operation.
However, the plant attendant performing the verification is fairly new to the plant and was not experienced in this particular operation.
The licensee stated that experienced people would be sent with new plant attendants in the future and that additional training would be given to all new plant attendants.
On Saturday, January 30, 1988, a plant tour took place for all plant site employees, their families, and close friends as well as invited guests.
The tour took them through portions of the turbine building, into access control, the auxiliary building, the Unit No. 2 containment to view the shutdown reactor, and the spent fuel pool.
The tour route was walked jown by the resident inspectors and special guardhouse / escort procedures monitored during the tour.
The resident inspectors noted that the tour went very smoothly with approximately 2,200 visitors attending.
8.
Meeting with Corporate Officials On January 6,1988 the resident inspectors met with the newly appointed Senior Vice President, Power Supply, Mr. R. Jensen, at the plant.
The following subjects were discussed:
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NSP Corporate organizational matters b.
Plant organizational matters c.
Plant followup on events and occurrences d.
Recent changes in NRC organization Meeting with Licensee in Region III offices, January 7, 1988 At the request of Northern States Power Co., a meeting was held in which the Prairie Island "Pursuit of Excellence" program was discussed.
At the instigation of NRC, a brief discussion was also conducted on the subject of the control of work in the plant substation.
Pursuit of Excellence - This plant program was initiated in the Fall of 1987 as a result of comments in NRC inspection reports, observations by INPO during the 1987 evaluation, and ideas generated within the plant for improving performance.
The program addresses improvements in nine specific areas:
a.
Internal communications and management awareness of plant events and problems, b.
Industrial safety.
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Long-term procedural and equipment problem resolution.
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emergency operating procedures are being upgraded to reflect the -lessons learned from NRC audits at other sites; a configuration management program somewhat similar. to Safety System Functional. Inspections (SSFIs) being done at other Region III plants is in progress.
d.
- Radiation protection program.
e.
Procedural compliance.
Comment:
the plant will be re-evaluating the guidance given to employees regarding when procedures may be-violated, f.
Attention to detail.
Comments:
the INP0 process for error reduction is factored in; the threshold for reporting problems to management has been lowered.
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Facility work performed by outside organizations.
h.
Quality of training.
Comments:
improvements are based on comments during NRC requalification exams in addition to-INPO observations; LERs, SOEs, and SOERs are all examined for potential input to the training program, i.
New challenges.
Comments:
plant employees will be getting experience at other Midwest nuclear plants; continuing evaluation of success in this area will be with.the company Integrated Management System which calls for at least annual appraisals.
Control of Work in Substation - Repetitive partial offsite power interruptions to the plant because of substation work prompted this special NRC review of control of work.
Following the last interruption on July 31, 1987, the licensee has taken the following actions:
placed a temporary hold on all work in the substation until a
temporary procedure for control of work was generated.
formed an interdepartmental task force to develop procedures
for controlling work.
developed the concept of Substation Coordinator, an individual e
who would be cognizant of all work to be done.
Items to be accomplished by the task force by April 1988 are:
prepare a Power Supply directive which will define the responsibilities of all who may have substation work to do, answer questions regarding the adequacy of substation procedures and training, review the question of electrical drawing availability and accuracy.
The implementation of the above corrective actions will be tracked under Open Item 282/88001-02(DRP).
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Licensed Operator Training (41701)
The inspectors participated in a number of simulator training sessions as part of an ongoing effort to more fully evaluate the effectiveness of the licensed operator training program.
Approximately 16 hours1.851852e-4 days <br />0.00444 hours <br />2.645503e-5 weeks <br />6.088e-6 months <br /> of simulator time was provided to the inspectors by several training instructors.
A number of events were simulated during these sessions including a reactor trip, a steam generator tube rupture, a steam line break, a LOCA, and ATWS, and a loss of offsite power.
For the most part, the procedures provided at the simulator were current and in agreement with those in the plant control room.
The training instructors were found to be very capable and professional during the simulator sessions.
The inspectors found the training sessions to be very beneficial for monitoring licensed operator training as well as plant control room operations.
10.
Licensee Event Reports and Part 21 Follcwup (92700)
Through direct observations, discussions with licensee personnel, and review of records, the following Part 21 was reviewed to determine that vendor recommendations were properly implemented.
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(Closed) 282/870lb-06-PP Anchor / Darling Valve Co.; check valves with (Closed) 306/87015-01-PP missing lock welds on hinge supports or hinge support capscrews The following event reports were added during this report period:
(0 pen) 282/87020-LL Autostart of No. 12 component cooling water pump on low pressure (0 pen) 282/88001-11 Loss of both control room chillers 11.
Emergency Planning (82301)
Detailed review of the Technical Support Center (TSC) is in progress by the licensee's consultant, Cygna Energy Services.
Possible changes to the arrangement of equipment, monitors, and other emergency aids are being evaluated.
The inspector's conclusions regarding noise levels and general TSC arrangement, based on the observation of emergency exercises, were passed on to the Cygna representatives.
The licensee hopes to implement some improvements prior to the annual exercise in June 1988.
12.
Exit (30703)
The inspectors met with the licensee representatives denoted in Paragraph 1 at the conclusion of the inspection on February 16, 1988.
The inspectors discussed the purpose and scope of the inspection and the findings.
The inspectors also discussed the likely information content of the inspection report with regard to documents or processes reviewed by the inspector during the inspection.
The licensee did not identify any document / processes as proprietary.
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