IR 05000309/1987017

Insp Rept 50-309/87-17 on 870611-0717.Violations Noted. Major Areas Inspected:Control Room,Accessible Parts of Plant Structures,Plant Operations,Including Plant Startups & Shutdowns,Radiation Protection & Physical Security

ML20236M137
Person / Time
Site:	Maine Yankee
Issue date:	07/30/1987
From:	Lester Tripp NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION I)
To:
Shared Package
ML20236K283	List: IR 05000309/1987017 ML20236K282 ML20236M124
References
50-309-87-17, NUDOCS 8708100482
Download: ML20236M137 (7)

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U.S. NUCLEAR REGULATORY COMMISSION Region I Docket / Report: 50-309/87-17 License: DPR-36 Licensee: Maine Yankee Atomic Power Inspection At: Wiscasset, Maine Dates: June 11 - July 17, 1987 Inspectors: Cornelius F. Holden, Senior Resident Inspector R

7hard . Freudenberger, Resident Inspector

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Approved: 8- {- 7/b/3 LV. E. Tripp, Chief, Reactor Projects Section 3A Datt Summary: Inspection on June 11 - July 17, 1987 (Report No. 50-309/87-17)

Areas Inspected: Routine resident inspection (239 hours0.00277 days <br />0.0664 hours <br />3.95172e-4 weeks <br />9.09395e-5 months <br />) of the control room, accessible parts of plant structures, plant operations, including plant startups and shutdowns, radiation protection, physical security, fire protection, plant operating records, maintenance and surveillanc Results: One violation was identified for failure to maintain a high radiation area door locked on several occasions.

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8708100482 870730 '

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DETAILS 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 staf . Summary of Facility Activities At the beginning of the report period the plant was shut down having completed low power physics testing and awaiting completion of repairs to the main tur-bine. A plant startup was conducted on June 18. Vibration problems were ex-perienced with the main turbine causing the plant to be shut down on June 2 During a test run of the turbine on June 27, the reactor was manually tripped when the level-in #3 steam generator approached its high level trip setpoin The high level was caused by an inadvertent interruption of the power supply to the #3 main fced regulating valve controller while maintenance was being performed on the controller. Repairs to the turbine were ongoing for the rest of the report period with several low power runs performed for turbine testin . Routine Periodic Inspections Daily Inspection During routine facility tours, the following were checked: manning, ac-cess control, adherence to procedures and LCO'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 order No unacceptable conditions were foun Systeis; Alignment Inspection Operating confirmation was made of the leakage monitoring system. This system includes the pressure switches which monitor containment pressure for the high containment pressure reactor trip, the containment isolation actuation signal, the safety injection actuation signal, and the contain-ment spray actuation signal. Visual inspection of the components was made and system alignment was checked. Operability of these instruments was assessed. No discrepancies were identifie 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 reviewe Plant housekeeping and cleanliness were evaluate No unacceptable conditions were foun I I

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l 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, jumper use, personnel qualifications, radiological controls for worker protection, fire protection, retest requirements, and deportability per Technical Specification The in-spector observed repairs to steam valves MS-79 and 9 The inspector had no question Surveillance Testing The inspector observed parts of tests to assess performance in accordance with approved procedures and LCO's, test results, removal and restoration of equipment, and deficiency review and resolution. Included in this review was the testing of the steam driven auxiliary feedwater pump (P-25B). No unacceptable conditions were found, Backshift Inspection The inspectors conducted backshift inspections on June 11, 15, 26, 28, July 1, 7, 9, and 1 No unacceptable conditions were foun . Manual Reactor Trip On June 27, 1987 at 12:53 a.m, the reactor was manually tripped when the level in number three steam generator reached 89% and was increasing. The trip set points for high steam generator water level is 91%. All systems responded as expecte At the time of the trip the level controll r for the number three steam gene-rator was in manual due to failure of automatic control of the number three main feed regulation valve (MFRV). Instrument and Controls technicians were preparing to replace the downcomer time lag circuit, which was the cause of the failure of the automatic control of the number three MFRV. When the In-strument and Controls technician disconnected a lead from a separate circuit on a common power source, power was lost to the number three MFRV controller causing the valve to fail open. The failed open MFRV caused the high level in the number three steam generator. The possible root causes of this problem appears to be inappropriate use of a print to determine circuits on the common power source and/or personnel error. The inspector had no further questions at this time, but is continuing to follow the licensee evaluation and result-ant corrective action l l

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l Observations of Physical Security i

Checks were made to determine whether security conditions met regulatory re- l 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 compensa-tory measures when require No unacceptable conditions were foun . Radiological Controls Radiological controls were observed on a routine basis during the reporting period. Standard industry radiological work practices, conformance to radio-logical control procedures and 10 CFR Part 20 requirements were observe Independent surveys of radiological boundaries and random surveys of nonradio-logical points throughout the facility were taken by the inspecto '.

On June 17, 1987, a door located in the upper level of the Spray Building, which controls access to the lower levels of the building, was found in an unlocked condition by the inspector. The lower levels of the Spray Building i are posted as an exclusion (locked high radiation) area. The door has a 1 self-locking device that latches when the door is closed; however, the door was ajar. The inspector informed Radiological Controls personnel in the vicinity that the door had been found in an unlocked conditio A sign was posted on the door that read "Please Hand Close Door", a Radio-logical Incident Report was initiated by a Radiological Controls supervisor, and a deficiency report was written and forwarded to Maintenance for repair of the doo On June 25, the inspector found the same door ajar again. A Radiological Controls technician in the area and a Radiological Controls supervisor were informe The licensee responded by performing a review of the corrective actions taken after the door had originally been found ajar. These corrective actions in-cluded repair of the locking mechanism and the initiation of a repair order to add additional bracing to the door. This repair order was assigned the highest priority, however its processing took four days. This review deter- j mined that the door lock had been repaired on June 23 and accepted as satis-factory by a Radiological Controls contractor technician on June 24, the day before it was found unlocked the second tim j Additionally, the licensee developed a set of corrective actions, including limitation of the responsibility of contractor technicians for verifying I acceptance of repairs unless explicit guidance is given, identification of a performance improvement opportunity for the Radiological Controls Department l to ensure that high priority work is accomplished in a timely fashion, in-  !

spection of all similar doors for proper functioning and establishment of a l monthly check of all self-locking doors that provide access control to locked high radiation areas. The significance of this unlocked door was judged by

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l the inspector to be low since personnel who need access to this area are operators who are trained and knowledgeable of the systems and hazards of this area. The inspector considers the deficiency to be in the lack of detail and follewup of repair verification This failure to maintain a door that provides access to a posted locked high radiation area in a locked condition is identified as a violation (50-309/

87-17-01). Overcurrent Protection for 480 volt Breakers Ca ing NRC Inspection 87-12, the NRC noted some discrepancies in the setting and calibration of EC overcurrent devices on some 480-volt electrical breaker lhe licensee committed to evaluate the overcurrent settings of onsite elec-trical breakers and recalibrates those breakers which the study showed required recalibratio On June 13, 1987, the licensee crosstied MCC-7A and 8A through breaker 7A and 8A and opened breaker 5071. Breaker 8F8A tripped open and momentarily de-energized MCC 7A and 8A. Breaker 5071 was reshut and the licensee recovered buses MCC 7A and 8A. Again on June 13, 1987, breaker 6081 was supplying buses 7 and 8 when it tripped open. All 480-volt power was lost for approximately 10 minutes while the licensee reduced loads on Bus 8. The plant was in hot shutdown condition at the time. Power was lost to service water pumps, emer-gency core cooling motor operated valves and four containment isolation valve The licensee was able to restore power to the 480-volt buses within 10 minutes with no adverse affects observed on plant conditions due to the loss of powe Technical Specifications 3.6.A and 3.11 allow a four-hour remedial action which was me The licensee identified the cause of the trip as improper recalibration of the 480-volt breaker overcurrent devices. The recalibration procedure allowed for the adjustment of the EC overcurrent device until the trip times were satisfactory. The instructions did not specify the amount of adjustment allowed. When breaker 6081 was recalibrates, an adjustment of significant magnitude was required on the short term trip setpoint. The overall affect was a reduction in the long term setpoint which caused the breaker to trip while under normal load condition Personnel from Yankee Atomic Electric Company were brought to the site to oversee the recalibration effor Procedural changes were made which mini-mized the adjustments allowed to the EC overcurrent devices. Additional testing of breaker setpoints was performed to ensure that adjustments to the short term setpoint did not affect the long term setpoint of the EC overcur-rent device. Replacement overcurrent trip devices were installed as necessar The inspector witnessed portions of the recalibration program and breaker alignment manipulations to support the recalibration program. The inspector had no further questions. This item is close _ _ _ _ _ _ - - _ _ - _ _ _

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8. Steam Driven Auxiliary Feedwater Pump l

Surveillance testing of the auxiliary feedwater pump during plant heatup identified a problem with the steam supply to that pump. Steam is provided to the pump's turbine from the main steam system through a pressure reducing valve. There is a safety valve, which was reconditioned during the outage, downstream of the pressure reducing valve to prevent overpressurizing the turbine's casing. A probicm arose when the safety valve lifted during the start sequence of the pump. The safety valve's operation vibrated the steam supply line which caused the turbine trip mechanism to vibrate and trip the turbin The safety valve was tested in the "as found" condition prior to any work being performed on it during the outage. The setpoint of the valve is 630 psig; however, the valve did not operate when pressurized to 700 psig. After repairs to the valve, it was shop tested and set using nitrogen. Nonetheless, once it was installed, it was found to operate erraticall The pressure reducing valve had no work performed on it during the recent outage; however, it was found that the valve could not control the steam supply pressure within the necessary control band on an automatic pump start.

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When the supply line was pressurized, the controller was found to allow the pressure to overshoot its setpoint (600 psig) and cause the safety valve to operate even when the pressure control valve was properly set. The charac-teristics of the pressure control valve had been masked by the relief valve which previously had not opened at the correct pressur The licensee pursued two methods to resolve the problem. A new safety valve l

was obtained and installed with an engineering evaluation which allowed a slightly higher setpoin An electronic controller was installed on the pressure reducing valve. The electronic controller allows the setpoint of i

the pressure reducing valve to be ramped up to 600 psig over a perica of 120 seconds. This prevents the pressure in the steam supply line from overshoot-ing 600 psi The licensee is processing an Engineering Design Change Request (EDCR) to re-locate the safety valve to a position where its operation will not cause the steam supply line to vibrate, yet where it will provide the necessary protec-tion for the turbine casin The inspector witnessed various portions of the installation and testing of the new equipment. The inspector had no further question . Main Turbine Vibration Each refueling outage, the licensee disassembles one of the two low pressure turbines for inspectio In years past, this type of inspection has identi-fied disc cracking at the keyway and blade root cracking. Corrective action taken has included the installation of redesigned discs with the keyway eliminated and redesigned attachment of the blades to the disc I l

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f During this refueling outage, cracks were identified in two rows of blading I

in the blade root area on both the blade and the disc in the turbine that was scheduled for inspection. The licensee chose to expand the scope of the tur-bine inspection to include the second installed low pressure rotor and the spare low pressure rotor. Of these three rotors, one was found free of crack The licensee decided to cut the cracked blades off one of the rotors and utilize the spare turbine rotor which had no cracks. Baffles were installed

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in the low pressure turbine where the blades were removed in order to assure l that normal pressure drop and flow distribution were maintained across those stages. The installation of the baffles resulted in derating the capacity i

of the uni Upon startup from refueling, vibration problems with the main turbine were eviden Several attempts were made to balance the machin The licensee also analyzed the vibration data to determine the cause of the high vibration The licensee established and implemented a three phase plan to correct the problem. The first phase centered on the easily accessible and highly suspect areas, while the second and third phase involved inspection and repair, if necessary, of the more inaccessible portions of the machin The first and second phase of this plan have been completed, with the third phase being implemented at the end of the inspection period. This third phase involves complete disassembly and inspection of both of the low pressure tur-bines and is expected to take approximately six weeks to accomplis . Exit Interview 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 inspectio l

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