IR 05000309/1986018
| ML20212C251 | |
| Person / Time | |
|---|---|
| Site: | Maine Yankee |
| Issue date: | 12/19/1986 |
| From: | Lester Tripp NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION I) |
| To: | |
| Shared Package | |
| ML20212C248 | List: |
| References | |
| 50-309-86-18, NUDOCS 8612290430 | |
| Download: ML20212C251 (7) | |
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U.S. NUCLEAR REGULATORY COMMISSION Region I W
Docket / Report: 50-309/86-18 License:
DPR-36 Licensee:
Maine Yankee Atomic Power Inspection At: Wiscasset, Maine Dates:
October 22 - December 12, 1986 Inspectors:
Cornelius F. Holden, Senior Resident Inspector Jeffrey Robertson, Resident Inspector David F. Limroth, Project Engineer R' hard. Freudenberger, Reactor Engineer Approved by:
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E. E. Tripp, Chief, Reactor Projects Section 3A
' D(te-Summary:
Inspection on October 22 - December 12, 1986 (Report No. 50-309/86-18)
Areas Inspected:
Routine resident inspection (187 hours0.00216 days <br />0.0519 hours <br />3.091931e-4 weeks <br />7.11535e-5 months <br />) of the control room, accessible parts of plant structures, plant operations, radiation protection, physical security, fire protection, plant operating records, maintenance and sur-veillance.
~Results:
No violations were identified.
Plant operators exhibited good plant control during the reduction in power on December 2, 1986.
Troubleshooting and testing of the steam driven feedwater pump was extensive prior to placing it back in service on December 2, 1986.
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DETAILS 1.
Persons Contacted Within this report period, interviews and discussions were conducted with various licensee personnel, including plant operators, maintenance technicians and the licensee's management staff.
2.
Summary of Facility Activities At the start of this inspection period, the plant was operating at 100 percent power.
On November 7, the plant reduced power to approximately 60 percent in support of raintenance of the Pownal substation.
Power was returned to 100 percent on November 10, 1986.
On November 15, 1986 a reactor trip occurred.
The first out annunciator in-dicated the cause of the trip was a trip of the steam driven feedwater pump (P-2C).
Dose equivalent iodine of the reactor coolant peaked at 3.43 uc/gm and then returned to normal.
A plant startup was conducted using the electric driven feedwater pumps on November 16 and power was returned to 97 percent (the maximum with electric driven feedwater pumps) on November 18.
On Novem-ber 20, Control Element Assembly (CEA) number 34 dropped and was recovered with no effect or, plant power.
On November 28, a primary component cooling water (PCC) pump (P-9A) developed a short.
P-9B was placed in service.
P-9A was repaired and returned to service on December 2.
On December 2, 1986, the plant determined that the control room breathing air system did not provide the required flowrate.
Both trains (A and B) of the system were declared inoperable placing the plant in the remedial action statement of section 3.0.A. of the Technical Specifications.
The plant began a shutdown. At 4:35 p.m. one train of the breathing air system was returned to service and the plant shutdown was terminated with power at 35 percent.
Power was increased, the steam driven feedwater pump was placed in service, and power was returned to 100 percent on December 5, 1986.
The control room air system was returned to full operation on December 5, 1986.
The plant remained at 100 percent power through the end of the report period.
3.
Follow-up on Previous Inspection Findings a.
(CLOSED) Violation (50-309/86-07-02).
Measures were not established to control, calibrate and adjust dial indicators used in safety related applications.
In a letter dated July 29, 1986, the licensee committed to place dial indicators, to be used in safety related applications, under the Measuring and Test Equipment Program (M&TE).
This action was verified to be complete and all dial indicators are now controlled by the M&TE program.
Additionally, all Maintenance Department procedures, where dial indicators may be used, require the use of a calibrated dial indicator.
The following were reviewed to verify dial indicators have been incorporated into the M&TE program:
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Identification number on dial indicators
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M&TE Control list
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M&TE Calibration List Usage log sheets and
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Method of calibration.
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b.
Short Term Accident and Procedure Review.
The licensee implemented symptom oriented Emergency Operating Procedures (EOP) on July 1, 1986.
These procedures use the Westinghouse Guidelines for Emergency Procedures.
All operators received two weeks of lecture and simulator training prior to implementation.
TMI Action Items I.C.1.2.B and I.C.1.3.8 are closed.
c.
Plant Safety Parameter Display Console.
The licensee implemented the Safety Parameter Display Console (SPDS) along with the new E0P's on July 1, 1986.
The system utilized the plant computer to generate information on the critical Safety Functions.
This system is integrated into the E0P's and all operators received training on the system along with E0P training.
TMI Action Item I.D.2.2 and I.D.2.3 are closed.
4.
Routine Pei' iodic Inspections a.
Daily Inspection During routine facility tours, the following were checked: manning, ac-cess control, adherence to procedures and LC0's, instrumentation, recor-der traces, protective systems, control rod positions, containment pres-sure, control room annunciators, radiation monitors, emergency power source operability, control room logs, shift supervisor logs, and operating orders.
No concerns were identified.
b.
System Alignment Inspection Operating confirmation was made of selected piping system trains.
Ac-cessible valve positions and status were examined.
Power supply and breaker alignment was checked.
Visual inspection of major components was performed.
Operability of instruments essential to system perform-ance was assessed for the Control Room Breathing Air System.
No problems were identified beyond those discussed in Section 4.h below.
c.
Biweekly Inspections During plant tours, the inspector observed shift turnovers, chemistry sample results and the use of radiation work permits and Health Physics procedures. Area radiation and air monitor use and operational status was reviewed.
Plant Housekeeping and cleanliness were evaluated.
No significant concerns were identified.
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d.
Plant Maintenance The inspector observed and reviewed maintenance and problem investigation activities to verify compliance with regulations, administrative and maintenance procedures, codes and standards, proper QA/QC involvement, safety tag.use, equipment alignment, personnel qualifications, fire pro-tection, retest requirements and reportability per Technical Specifica-tions.
Corrective maintenance on the Control Room Breathing Air System was observed.
e.
Surveillance Testing The inspector observed parts of tests to assess performance in accordance with approved proceuures and LCO's, test results, removal and restoration of equipment, and deficiency review and resolution.
Emergency Diesel Generator (DG-18) and Auxiliary Feedwater Pump P-25B monthly surveil-lances were observed.
No deficiencies were identified.
f.
Plant Trip Due to Loss of Feedwater Pump (P-2C)
On November 15, 1986, the plant tripped from 100 percent power.
The cause of the trip was a trip of the steam driven feedwater pamp (P-2C).
All plant systems responded as expected.
Plant personnel conducted the normal post-trip reviews and the plant was returned to power operations on November 16 using the electric driven feedwater pumps.
An investigation into the cause of the P-2C trip was initiated.
A matrix
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of issues and data, their significance, required actions to resolve and i
section responsibility was initiated to track the progress of the in-vestigation.
This matrix identified both long term and short term ac-tions necessary to resolve this P-2C trip.
J As a result of this investigation, the following scenario was determined to be the cause of the P-2C trip.
A loose wire on the lube oil relay switch interrupted power to the operating main lube oil pump. This auto-matically started the standby lube oil pump; however, the pressure transient experienced by the lube oil system was sufficient to cause P-2C to trip on low lube oil pressure.
A trip of P-2C causes a turbine trip
which results in a reactor trip.
The root causes of this trip were the loose wire on the lube oil relay and pressure drop in the lube oil header as a result of the lube oil pump switchover.
The plant conducted an inspection of the lube oil system as well as a number of tests.
The inspection revealed leaks in some flange joints in the lube oil piping.
During normal operation, these leaks are un-noticeable since the piping is located in the lube oil sump.
These flange leaks will be repaired during the next refueling outage when full isolation of P-2C is possible.
Testing of the lube oil system showed that after the lube oil system was aligned for normal operation, these flange leaks allowed the discharge piping for the standby pump to drain
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over a period of approximately 5 hours5.787037e-5 days <br />0.00139 hours <br />8.267196e-6 weeks <br />1.9025e-6 months <br />.
If the standby pump was required to start on the low oil pressure signal (80 psig), the pump could not start fast enough to maintain header pressure above the P-2C trip set-point (60 psig).
If the standby pump was required to start before the discharge header had an opportunity to drain, then the system could function as required and no trip would occur.
The plant installed a priming line that crossconnects the discharge of the main lube oil pump with the discharge of the standby pump.
This priming line prevents the discharge piping from draining and allows switching of the main and standby lube oil pumps without a low lube oil pressure trip of P-2C.
P-2C was returned to service on December 2, 1986.
The licensee continues to track long term issues in order to improve the reliability of P-2C; the inspector will follow long term licensee actions.
g.
Dropped Control Rod At 9:09 a.m., November 20, with the reactor at 97.5 percent power, con-trol rod group 5A was being pulled to the upper limit for symmetrical offset control when "CEA Position Deviation Reed Switch" alarmed.
The Reactor Operator took individual control of rod 34 to drive it in to clear the alarm.
During this evolution, the rod dropped.
The rod was recovered to its proper position within 6 minutes in accordance with approved procedures.
(Technical Specification 3.10.A.3 allows 15 minutes prior to invoking power limitations).
The inspector had no further questions.
h.
Control Room Ventilation On December 2, 1986 the plant declared both trains (A and B) of the con-trol room breathing air inoperable.
Technical Specification (T.S.)
3.25.B requires two trains of control room ventilation to be operable whenever the reactor is critical.
Since the plant was outside of this specification, they correctly followed the limiting condition for opera-tion of T.S. 3.0.A which requires the plant to commence a shutdown within one hour and be in hot shutdown within six hours.
Approximately five
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hours after the breathing air system was declared inoperable, one train was returned to service.
The plant terminated the shutdown with power at 35 percent power.
With one train of breathing air operable the plant is allowed by T.S. 3.25 to remain in operation for 14 days.
Both breathing air systems were returned to operation on December 5, 1986.
The breathing air system contains a fan, a filter system, piping and rotometer (to measure air flow).
Its purpose is to provide clean air to the control room during accident conditions.
Two surveillance tests are required by T.S. section 4.11.
The first is a monthly operability test which requires flow be initiated for at least 15 minutes.
The second surveillance is a refueling interval test which requires effi-
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ciency of the filters be n'easured and a flow rate be determined.
This measurement is performed by the manufacturer who measures suction flow-rate.
During the performance of the monthly surveillance of the breathing air system on December 1, 1986, the operators utilized a procedure 3.1.18 Rev 2.
This procedure requires a 15-minute operability test which was completed satisfactorily.
In addition to the required fan run time, flow measurements were taken utilizing the installed rotometers in the control room.
Since these rotometers are calibrated to a specific overpressure, the initial readings must be corrected to normal atmospheric pressure.
The Flant Engineering Department was requested to analyze this informa-tion and provide the plant with a corrected flowrate. At 11:30 on December 2, the breathing air system was declared inoperable based on a corrected flowrate of less than 40 CFM.
The plant conducted a review of the system and determined that the check valves that are installed in each train of the breathing air system account for the majority of the pressure drop in the system.
These check valves protect one train from disabling the other train in the event of a failure.
The plant decided to isolate the A train of the breathing air system and remove the check valve internais on the B train.
This provided the necessary protection from a failure of one system affecting the other and it provided for acceptable flow through the B train.
The plant terminated the shutdown at 4:35 p.m. on December 2, 1986.
The plant subsequently replaced the check valves in both the A and B train and performed the flow test satisfactorily on December 5.
The inspector had no further questions.
i.
Cold Weather Protection In preparation for cold weather operations, the plant performs several functions to ensure all systems are protected against freezing. These actions include alignment checks of heating units, installation of covers over outside air intakes and ensuring steam is aligned to outdoor tanks.
Operations Department utilizes procedure 1-202-2 to ensure all activities are completed, The inspector reviewed this completed procedure and con-ducted a check of various systems.
No discrepancies were identified.
5.
Observations of Physical Security Checks were made to determine whether security conditions met regulatory re-quirements, the physical security plan, and approved procedures.
Those checks included security staffing, protected and vital area barriers, vehicle searches and personnel identification, access control, badging, and compensatory meas-ures when required.
No discrepancies were identified.
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6.
Radiological Controls Radiological controls wr/e observed on a routine basis during the reporting
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period.
Standard industry radiological work practices, conformance to radio-logical control procedures and 10 CFR Part 20 requirements were observed.
Independent surveys of radiological boundaries and random surveys of nonradio-logical points throughout the facility were taken by the inspector.
No discrepancies were identified.
7.
Exit Interview
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i Meetings were periodically held with senior facility management to discuss the inspection scope and findings. A summary of findings for the report period was also discussed at the conclusion of the inspection.
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