IR 05000271/1987008
| ML20214R500 | |
| Person / Time | |
|---|---|
| Site: | Vermont Yankee File:NorthStar Vermont Yankee icon.png |
| Issue date: | 05/20/1987 |
| From: | Blumberg N, Finkel A NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION I) |
| To: | |
| Shared Package | |
| ML20214R497 | List: |
| References | |
| 50-271-87-08, 50-271-87-8, NUDOCS 8706080177 | |
| Download: ML20214R500 (8) | |
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U.S. NUCLEAR REGULATORY COMMISSION
REGION I
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Report No.
50-271/87-08 i
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Docket No.
50-271 License No.
Licensee:
Vermont Yankee Nuclear Power Corporation RD 5, Box 169
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Ferry Road
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j Brattleboro, Vermont 05301
Facility Name: Vermont Yankee Nuclear Power Station
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Inspection At: Vernon, Vermont
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Inspection Conducted: April 20-24, 1987
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Inspectors:
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i A. Finkel, Lbad Reactor Engineer p date Approved by:
[. b b 9%r)9/TU i
N. Blumberg, CI(Jef, Operational Programs
/ date Section, 08, DRS Inspection Summary:
Routine, announced inspection conducted on April 20-24, 1987 (Report No. 50-271/87-08)
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Areas Inspected:
Routine announced inspection of licensee's activities in the j
areas of inspection and modification of the RHR Pump Motors and Pump Internals,.
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and the maintenance program associated with RHR Pump Motors and the Station Start-Up Transformers.
Results: No violations or deviations were identified.
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R706000177 870522
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PDR ADOCK 05000271 O
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DETAILS
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1.0 Persons Contacted Vermont Yankee Nuclear Power Station
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R. Connell, Project Engineer, RHR
- P. Donnelly, Maintenance Superintendent
- R. Grippardi, Quality Assurance Supervisor
- R. Lapriore, Maintenance Supervisor
- J. Pelletier, Plant Manager Bingham-Williamette Company A. Koltowich, Field Service Engineer, RHR United States Nuclear Regulatory Commission
- W. Raymond, Senior Resident Inspector
- Denotes those present at the exit interview.
The inspector also held discussions with managers and supervisors and other contractors and licensee employees during the course of the inspection, including operations, technical and administrative personnel.
2.0 Maintenance Organization
Maintenance activities are controlled and conducted by the onsite main-
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tenance section.
The maintenance section is made up of two main groups:
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mechanical and electrical group which function under one supervisor and
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the instrumentation and control group which is under another supervisor.
The two maintenance supervisors report to the Maintenance Superintendent, who in turn reports to the Plant Manager.
2.1 Maintenance Activities 2.1.2 Administrative Controls Administrative controls were reviewed to evaluate the licensee's program for implementing requirements associated with preventive and corrective safety-related maintenance activities. The objectives were to assure that the licensee programs were con-sistent with the Technical Specifications (TS), Regulatory Guide (RG) 1.33, and ANSI N18.7-1972, " Administrative and Controls for Nuclear Power Plants." Due to the scope of the Residual Heat Removal (RHR) pump modification, the maintenance procedures and drawings were reviewed for compliance with the objectives of the TS, RG and ANSI N18.7-1972.
Documents reviewed are listed in Attachment 1.
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2.1.3 Program Review / Implementation The inspector held discussions with the RHR maintenance project engineer, Bingham-Williamette Project Field Engineer and the Thomas O'Connor general contractor, whose personnel were performing the RHR modification work. A review and evaluation of the controls in place used to identify, schedule, track, perform and document the maintenance activities were performed by the inspector. Maintenance activities are controlled via the Maintenance Request (MR) which provides the administrative control for identifying, initiating, planning, tracking and reporting maintenance activities.
2.2 Residual Heat Renoval System (RHRS)
The licensee has four Bingham-Williamette Model 16x18x26 CVIC pumps, each connected to a General Electric Vertical High Thrust Polyphase Induction Motor, per GEH-1897B manual. As a result of problems identified with similar CVIC Bingham-Willamette pump impeller wear rings (NRC Information Notice 86-39), the licensee devised an inspection program consisting of two parts: 1) inspect the impeller wear rings and replace the present designed impeller with a new single cast impeller, and 2) perform Preventive Maintenance (PM) on the General Electric motor.
2.2.1 Bingham-Willamette Pump (B-W)
The B-W pump is a vertical, single stage, single suction pump with in-line suction and discharge nozzles.
The pump is driven by a vertical motor through a Bingham split sleeve coupling.
The stuffing box is designed with a mechanical seal and has a seal gland cover which allows collection and drainage of seal leakage.
Clean flushing is provided to the seal faces and the cartridge journal bearing by a bleed off line taken from the pump discharge.
This line has a separator to insure clean
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liquid to the seal. During the disassembly of this part of the pump, the inspector verified that the system was not plugged.
The impeller is hydraulically balanced. Axial balance is achieved by balance holes through the impeller hub.
The inspector verified that these holes were located per the as-built drawings in the new impeller.
During the disassembly and replacement of pump parts, the inspector verified that the following conditions were complied with:
An MR was issued defining the scope of work and required
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procedures to be used,
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Health Physics (HP) notified and criteria posted Shift Supervisor notified of work space and 'B'
RHR pump
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sealed
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Operators recording 'B' RHR system leakage
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"B" RHR pump isolated, vented, drained and tagged out of service Correct supply breakers opened for V10-13 and V10-15 of
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the affected RHR pump loop.
In this example the inspector verified that the 'B' RHR pump loop was correctly tagged out, drained and vented Notify vendor QC prior to start of work as required by
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procedure
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Training program completed by all personnel working on the RHR pump modification During the inspection of the
'B' RHR pump, the pump wear rings were replaced in addition to replacing the old impeller shaft with a new designed impeller shaft. The new wear rings were machined to size and locking pins drilled as per the require-ments of procedure 0.P. 5200.33, Revision 1, Section 6.5.
2.2.2 RHR Motor Disassembly The General Electric Vertical High-Thrust, Polyphase Induction Motor (GEH-1897B) was serviced in a lay down area located out-
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side of the main plant. The inspector verified that the prerequisites, as listed in OP 5200.34, were complied with prior to starting work.
The inspector witnessed the major areas of work performed on the 'B' RHR pump motor as listed below:
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Polarization index test for 10 minutes at 2500 volts Megger test on motor at 1000 volts
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Motor Disassembly
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Bearing Removal j
Cleaning and Inspection of rotor, stator j
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Varnish applied to stator windings Megger testing of stator 0 1000 volts
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The inspection of the pump casing pump impeller indicated the following conditions:
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(A.) Pump Casing
No evidence of any galling wear or cracks on the
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i lower casing wear ring
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All wear ring cap screws present and tac welds intact j
Minor-indications of cavitation erosion on the
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leading edge of the casing volutes.
Estimate 20-25
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pits with a maximum depth of approximately 1/6"
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Pump internal surfaces showed no evidence of general
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I corrosion or erosion. No loose or flaking corrosion products were present Casing bolting flange and gasket area showed no
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evidence of wear, erosion or cracking t
(B.) Pump Impeller P
t The impeller had a thru-wall crack on the upper wall
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i of the shroud external to the diameter of the upper I
wear ring. The crack appeared to originate frem the
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internal surface of the impeller shroud at several (3/16") pits.
The pits were smooth and somewhat J
random and appeared to be casting defects as opposed to cavitation induced. The crack propagated
circumferentially for approximately 41/2"
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General condition of the impeller was excellent
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i except for the items discussed above
The above observations were made during the inspection of
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the Bingham-Willamette pump at the 'B' RHR pump location.
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The licensee will perform a detailed examination of the i
j pump parts at a later date.
No violations or deviations were identified.
3.0 Startup Transformer Inspection
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l The inspector reviewed the licensee's maintenance program for large trans-i formers and reviewed the chemical analysis to determine the overall j
condition of the units inspected.
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Start-Up Transformers (SVT) 3A and 3B were selected by the inspector to determine the methods and programs used by the licensee to determine the overall operational characteristics of nine transformers.
l The SUTs are General Electric Type 0A/FA/F0A, serial numbers G8604368 and
G860436A. The maintenance department performs monthly oil samples which
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are sent out for a gas-in-oil analysis.
Preventive maintenance is
performed on an outage frequency with the following tests, inspection and analysis performed.
Megger testing
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Doble testing
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Dielectric testing
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Inspection of Transformer
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Oil analysis
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The Doble Engineering Company has indicated that their data shows that an increasing number of transformer problems are being attributed to the oil-circulating pumps. The failure of various components within these pumps can result in local overheating of motors and/or fine metal par-
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ticles being distributed throughout the transformer.
This can cause gas generation, power factor degradation, and possible winding failure. Based on the above Doble testing data, the licensee has started a metal-in-oil test program which is being performed approximately every three years.
Since this is a new type of test, results are currently being evaluated to determine the effectiveness of the test.
No violations or deviations were identified.
4.0 Maintenance Procedures The equipment qualification program manual QDR4.4, El, Revision 3, states,
"that standard maintenance requirements for such items as bearings is part of the plant maintenance procedures (see Tab G3)." Tab G3 is a section
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which describes the maintenance requirements for large," AC Motors -
Vertical Frames 504 through 688.5 -Drip proof-WPI Construction Squirrel
Cage and Wound Rotor." Under the section on lubrication the requirement for motor oil changes is stated as "The oil should be changed at six month intervals." Presently the oil change is performed on the RHR pump motor every refueling outage and not on a six month schedule, as recommended in
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the QDR manual.
The licensee has a contract with the General Electric (GE) Company to review GE's maintenance requirements based on plant condition and j
component history. This review will include the QDR requirement for oil l
l change every six months versus the licensee's present practice of changing
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j oil every refueling outage.
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This item is considered unresolved and the final maintenance schedule developed by the licensee following GE's evaluation will be reviewed during a later NRC inspection (50-271/87-08-01).
5.0 Quality Assurance The licensee provided third party inspection of the contractors quality assurances program for the RHR modification work.
The inspector verified that the contractors quality control program for the RHR modification work was approved by the licensee's quality assurance organization. A change was made to the contractors quality control program in the area of control and use of calibrated tools.
In this area the licensee was providing the calibrated tools and the certification from their M&TE laboratory. No violations or deviations were identified.
6.0 Unresolved Items Unresolved items are matters about which more information is required in order to ascertain whether they are acceptable items, or violations. An unresolved item is discussed in paragraph 4.0.
7.0 Exit Meeting The inspector met with licensee management representatives (see section 1.0 for attendees) at an exit meeting on April 24, 1987, and summarized the scope and findings of the inspection at that time.
At no time during this inspection was written material provided to the licensee by the inspector.
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ATTACHMENT 1 Documents Reviewed RHR Pump Maintenance Procedures 0.P. 5200.33, Revision 1, December 29, 1986, RHR Pump Disassembly and Reassembly; 0.P. 5200.34, Revision 1, December 29, 1986, RHR Pump Disassembly and Reassembly; Bingham-Willamette Company Installation; Operation and Maintenance Instructions, Series 10324; General Electric Vertical High-Thrust Polyphase Induction Motors Instructions, GEH-18978 Plant Administrative Procedures A.P. 6024, Plant Housekeeping A.P. 0042, Plant Fire Protection A.P. 6025, Quality Control / Independent Inspection A.P. 0620, Chemical Material Control A.P. 0200, Maintenance Program Drawings Vermont Yankee Drawing, 5920-1077, Residual Heat Removal Pump, i
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