IR 05000282/1990006
| ML20043D157 | |
| Person / Time | |
|---|---|
| Site: | Prairie Island  |
| Issue date: | 05/31/1990 |
| From: | Burgess B NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION III) |
| To: | |
| Shared Package | |
| ML20043D154 | List: |
| References | |
| 50-282-90-06, 50-282-90-6, 50-306-90-06, 50-306-90-6, NUDOCS 9006070184 | |
| Download: ML20043D157 (9) | |
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U. S. NUCLEAR REGULATORY COMMISSION
REGION III
Reports No.- 50-282/90006(DRP);50-306/90006(DRP).
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Docket Nos. 50-282; 50-306 License Nos. DPR-42; DPR-60-
i Licensee:. Northern States Power Company
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414 Nicollet Mall Minneapolis, MN 55401
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f facility Name:
Prairie Island Nuclear Generating Plant Inspection At:
Prairie Island Site, 200 Wing, MN Inspection Conducted: April 10 through May 21, 1990 Inspectors:
P. L. Hartmann s
.T. J. O'Connor J. M. Ulie cQw.,]
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Approved By:[s0. L. Burgess, Chief V
Reactor Projects Section 2A-Date
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Inspection Summar,v, j
Inspection on Aaril 10 through May 21,1990 (Reports No. 50-282/90006(DRP);
ED:3DE79DDDE iDRP))
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Areas Inspected:. Routine unannounced inspection by resident inspectors of'
plant operational -safety,- maintenance. surveillance, and fire prctection.
Ensults:
During this inspection period both units up reted at 1007 power w ith tiie exception of_ Unit 2 experiencing o four d6y forcea outage.
The outag wet induced from a high voltage disconnect failure on the C phase of the Nain trans former. The root cause of the failure appears to be lack of preventive j
maintenance. The licensee entity which provides this maintenance is an
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offsite company support group.
There were three unplanned starts of the spent fuel pool special ve'ntilation
system which are similar to past repetitive problems with radiation monitor
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spurious activations. - Also, _ the voltage restoration logic was activated for-
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safeguards bus 15, resulting in an unplanned emergency diesel generator start.
This type activation has occurred during voltage restoration testing in the
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pdst.dnd corrective action will be reviewed as an unresolved item.
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Overall, plant perfonnance was good, with the exceptions discussed above.
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'9006070184 900531 PDR ADOCK 05000282
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Of the four areas inspected, one unresolved item and one violation of NRC requirements was identified.
However, in accordance with 10 CFR Part -2,
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Appendix C,-Sections V;A. and V.G., a Notice of Violation was not issued.
The-violation involved the failure to declare the normal supply power to the D2 Emergency Diesel Generator to be a safe shutdown cable as required for Appendix R' concerns. This matter is discussed in Paragraph 7.
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DETAILS
1.
Persons' Contacted
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- E. Watzl, Plant Manager-0 Mendele, General Superintendent, Engineering and Radiation i
Protection
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- #M. Sellman, Manager, Corporate Security G. Lenertz, General Superintendent, Maintenance'
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- #A.' Smith, General Superintendent, Planning and Services R. Lindsey, Assistant to the Plant Manager
'D Schuelke, Superintendent, Radiation Protection
G. Miller, Superintendent, Operations Engineering LK. Beadell, Superintendent, Technical Engineering S. Schaefer, Superintendent, Technical Engineering H. Klee, Superintendent, Quality Engineering R. Conklin, Supervisor, Security and Services
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- M. Wadley, General Superintendent, Operations G. Eckholt, Nuclear Support Services
- J. Leveille, Nuclear Support Services
- A. Hunstad, Staff Engineer
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// Denotes those present at the exit interview of May 25, 1990.
2.
Licensee Action on Previous Inspection Findings (92701)
a.
(Closed) LERs 282/89-006, 009, 012 015, and 020-LL: Autostart of
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Control Room Cleanup System Due to Spiking of Chlorine Monitors.
LicenseeEventReports(LER) 282/89-006, 009, 012, Olb, and 020-LL-document various unplanned automatic initiations of the 121 and 122 trains of the Control Room Clean Up System due to electrical sp de.;
generated by the system's chlorine monitors. These spikes resuiced from various causes including jammed detector paper, misaligned'and dirty' optics' blocks, torn detector paper,: failed electrical components,
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and failed sample pumps.
The_ chlorine monitors are used to identify-
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a _high chlorine concentration entering the control room ventilation system through the intake ducts, isolate the control room from the chlorine by closing the isolation dampers in those ducts before the concentration in the control room can reach an unacceptable level, and. initiate the control room ventilation cleanup system to remove
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any chlorine entering-the system.
Previous actions by the licensee were directed at increased surveillance and maintenance of the-
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detectors and were not completely successful.
In response to the continued unplanned, automatic initiatit.u of the
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Control-Room Clean Up System, the licensee has modified the actuation logic. Previously, the logic was such that a spurious L
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high chlorine signal on any one of the two detectors per train would
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actuate the associated train of the Control Room Clean Up System.
The modification has installed two additional detectors in the 122 Train, so that the revised logic requires two chlorine detectors to trip before an actuation signal is generated (a 2 out of 2 logic).
Additional detectors were not added to the.121 Train, pending a long term solution.
The 121 Train has been placed in the bypass position, forcing entry into an allowable Limiting Condition for Operation.
Technical Specification 3.13 B.I.b states that if one train of chlorine detection is inoperable, the outside air supply dampers for the affected train of ventilation shall be closed.
This issue and the corrective actions described above was described by a letter dated October 5, 1989 from the licensee to the Projects Branch 2 Chief.
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The modification was completed in late December of 1989, and to date there have been no actuations of the Control Room Clean U) System as a result of electrical spikes generated by the system's calorine monitors. The licensee is performing an overhaul of the chlorine
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monitors. Additionally, the licensee has added chlorine monitor inputs to the plant computer which notifies the licensed operators of downscale failures and low level alarms.
Based on the above information, this item is considered closed.
b.
(Closed)LER 282/90001-LL: Automatic Control Room Isolation and Start of Control Room CTeanup Fan Due to Personnel Error During Surveillance Test.
LER 282/90001 documents the unplanned automatic initiation of the Control Room Cleanup System.
The initiation occurred when an I&C technician, using a small mirror to view the optics block portion of the monitor, accidentally contacted a bare power supply terminal and shorted it to ground, tripping the power supply which caused the automatic initiation of the Control Room Cleanup System.
In response to this event, the licensee initiated and completed work requests P2503-ZN-Q and P2538-ZN-Q. These work requests taped all exposed wires and installed terminal strip covers in the chlorine detector cabinets.
Based on the above information, this item is considered closed.
c.
(Closed) Violation 282/90002-03(DRP)
A notice of violation was issued due to persornel deenergizing the wrong unit (Prairie Island Unit 2) control rod lift coils during a surveillance performed by I&C personnel. 'In response, the licensee has locked the cabinets with distinct key padlocks requiring key authorization from the operations shift supervisor. The inspector
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verified this action.
In addition, the event and the requirements
of supervising less experienced technicians was discussed during a working group meeting of I&C technicians. This matter is closed.
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d.
(Closed)LER 282/87015-LL:
Severe Weather Caused Partial Loss of Offsite Power On July 27, 1987, a tornado caused power to be interrupted on'one of the two 345 kv distribution lines. This resulted in lockout of No, j
10 transformer, one of the sources of offsite power to the i
" Safeguards"_ buses.
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inoperable one was returned to service during the event. Much j
electrical equipment tripped during the-event and was restored j
manually. One cooling water pump tripped, causing automatic start
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of No. 12 diesel driven cooling water pump.
Since this event the licensee has considered several other corrective j
actions and plans to communicate this to the NRC via an updated LER.
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This action item is being tracked as an Operations Committee controls i
action item. Also since this event the licensee has begun l
construction of the Station Blackout Project (SBO) which includes; l
installation of two additional EDGs, construction and redesign of the emergency safeguards buses to 1.mprove electrical isolation between units, and provide a safeguards power supply to the 121-(vertical)
cooling water pump.
This project is in progress and is scheduled for completion in 1992.
This initiative will significantly reduce the
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potential impact of severe weather on any safeguards equipment, j
3.
Operational Safety Verification (71707, 93702)
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a.
Routine Inspection d
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The inspector observed control room operations, reviewed applicable
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logs, conducted discussions with control room operators and observed shift turnovers. The inspector verified operability of selected i
emergency systems, reviewed equipment control records,.and verified
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the proper return to service of affected components, conducted tours
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of the auxiliary building, turbine building and external areas of
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the plant to observe plant equipment conditions, including potential
fire hazards, and to verify that maintenance work requests had been initiated for the equipment in need of maintenance.
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b.
Shutdown to Repair 345 KV Disconnect On April 11, 1990, the licensee observed arcing on the C phase of
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the high (demand) side disconnect for the Unit 2 main generator transformer.
Licensee management decided to shut down the unit promptly to make repairs.
A reactor shutdown was commenced at 1735 with the unit off line at 2004. As the main turbine generator was being slowed and in preparation for system shutdown, an oil leak occurred on the main thrust bearing, which is located between the low pressure (LP) turbines. The oil leak was observed by the turbine building operator at 0045 on April 12, 1990, while the
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turbine was spinning at about 400 rpm. Operators broke vacuum in l
order to stop the turbine shaf t's movement as promptly as possible.
The 345 KV disconnect contact fingers were slightly misaligned which caused the arcing.
The misalignment was corrected and the disconnect
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was returned to service.
The oil seal leak required onsite repair and machining to the turbine shaft seal seat.
Following these repairs, the licensee unsuccessfully attempted to latch the turbine generator at 0453 (output breaker 8H13) and at 0455 (output breaker 8H14) on-April 16, 1990.
Following a review of the closing logic for the output breakers, the problem was identified as the lack of a closesignalforthegeneratorfield(480v) breaker.
Investigation I
reviewed this 480v breaker was closed and operating properly; however, the auxiliary contact stabs which pass a close signal to the close i
logic for the generator field breakers were not making contact.
i The breaker was racked out, inspected, and racked in. The stab for the breaker close signal was verified as having continuity. Following i
these efforts the generator was placed on line at 0903 April 16,1990
without incident, c.
Engineering Safeguards Feature (ESF) Act;ations i
There were four ESF actuations during the report period. The first
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was on May 4,1990, when an autostart of the 121 Spent Fuel Pool l
Special Exhaust Fan occurred. The cause was an electrical spike on
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R-25 radiation monitor, believed.to be caused by ongoing work to an
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adjacent panel drawer for radiation monitor R-21.
This event will be followed by LER No. 282/90005-LL._ On May 14, 1990, the 121 Spent Fuel Pool Special Exhaust Fan auto started again.
The cause was a spurious electronic spike on R-25.
There was no work activity near the radiation monitor hardware in this case.
For electronic
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spiking induced ESF actuations, the licensee has been pursuing-an
electronic time delay or other filtering to eliminate the initiation
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signal for spurious signals. The second event will also be tracked i
by LER No. 282/90005-LL..
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On May 17, 1990, while performing a performance test of radiation monitor 25, the source used also caused R-31 to sense high radiation and resulted in an autostart of the 122 Spent Fuel Pool Special Exhaust Fan. The cause was the close proximity location of the
detectors to each other in the Auxiliary building. Normally for this
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p(articular routine testing, the adjacent non tested radiation monitor R-25 or R-31) trip function is bypassed when testing is performed.
During this event, R-25 was undergoing post maintenance testing and the R-31 trip function was not bypassed. This event and prescribed
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corrective actions will be reviewed by the inspector during followup inspection of LER No. 282/90006-LL.
On May 18. 1990, while performing surveillance testing of the
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undervoltage detection circuit for the No. 15 safeguards bus, a i
blown fuse caused the undervoltage detection logic to sense a false undervoltage condition.
The voltage restoration system stripped the
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W No.15 safeguards bus and re-powered' the bus via the D-1 Emergency
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Diesel Generator.
The No. 12 Component Cooling (CC); pump started on
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low pressure, shortly following the loss of power to the operating
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k No. 11 CC pump.. The Nos. 11 and 13 Containment Fan Coil units; the 121 control room chiller and the 121 air compressor lost power and
e were restarted as required, following bus restoration.
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.The cause of the blown fuse was grounding the "C" phase voltage.
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detection relays across its protective fusing. :This grounding W
occurred when a test lead attached to terminal wiring for the-surveillance rotated from gravity, and came into contact with the
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adjacent Wiring..
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t The inspector is reviewing this event. Past similar events and the corrective actions to prevent recurrence will be identified and t
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. evaluated. - The inspector observed portions of the test following-the event and concluded the personnel involved were experienced and-l)
conscientious in their actions. The placement and position requirements for test leads in this particular test are perilous
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regarding the likelihood for the generation of the undesired
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-undervoltage signal due to shorting terminal contacts during testing.
T This matter is Unresolved pending inspector review of similar events E
and past corrective actions.
(282/90006-01(DRP)).
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4.
Maintenance Observation (71707, 37700, 62703)
Routine, preventive, and corrective maintenance activities were observed to; ascertain that they were conducted in accordance with approved -
procedures, regulatory guides, industry codes or standards, and in t
conformance with Technical Specifications. The following items were l
considered during~ this review: adherence'to limiting conditions for operation 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.
i 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
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-implemented, and fire prevention controls were implemented, o
Portions of the following maintenance activities were observed during the
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.p Investigation and Repair of No. 13 Charging Pump Intake Valve
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Leakage Replacement of D-2 Emergency Diesel Generator Fuel Oil
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. Fitting
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Replacement of Desurger for No. 12 Charging Pump
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PreventiveMaintenance(PM) 3134-1-11 No.11 Auxiliary
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Feedwater Pump Suction Line Semi Annual Flush
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During performance of No.11 Auxiliary Feedwater (AFW) Pump Suction Line flush, the motor operated valve (MOV) 32025 did not fully close following remote closure.
The valve was fully closed manually with no anomalies.
The line was reflushed and the valve was cycled remotely with no further c
complications. A small amount of marine biological matter was obtained
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following the reflush, which was granular in size. The licensee concluded the foreigr, matter prevented full close indication due to slight blockage of full closure travel. This valve provides no automatic function, and is
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opened to provide a backup AFW supply.
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No violations or deviations were identified.
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Surveillance (61726, 71707)
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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, by observing that procedures were being(LCOs) were not violated, thatfollowe
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that Limiting Conditions for Operation
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system and equipment restoration was completed, and that test results were -
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dCCeptable to test and Technical Specification requirements.
SP.1102 No.11 Turbine Driven Auxiliary Feedwater Pump Test i
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SP 1218 Bus 15 Undervoltage Relay Test
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SP 2093 EDG-2 Manual Test
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SP 1102 No.11 Turbine Driven Auxiliary Feedwater Pump Test
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No violations or deviations were identified.
6.
Sgecial Report Review
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By letter dated March 26, 1990, the licensee submitted a Special Report i
due to fire suppression system inoperability.
The following information was taken from the report.
On Wednesday, December 20, 1989, the Prairie Island plant staff.took
screenwash pump 121, motor driven fire pump 121, and diesel driven fire pump 122 out of service to do normal maintenance on a number of leaking fire protection valves. These pumps were out of service from 1:45 a.m. to 9:52 p.m., for a total of 20 hours2.314815e-4 days <br />0.00556 hours <br />3.306878e-5 weeks <br />7.61e-6 months <br />.
Prior to taking these pumps out of service and during the time they were out of service, ~ two 4" crossover valves from the plant cooling water header were open to supply pressure to the fire header.
In addition, six other 3" and 4" cooling water crossover valves were available for use if they had been required.
During this time, the cooling water header pressure maintained 112 psi with cooling water pumps 11 and 12 running. The three backup cooling water pumps were also available.
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Technical Specification 3.14.B.3 requires that with the fire suppression system inoperable, establish a backup-fire suppression water system within
,a 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br />, and provide a special report to the Commission within 30 days-outlining the actions;taken and the plans and schedule for restoring.
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the inoperable system to operable-status. Accordingly,. the licensee did establish a backup fire suppression water system within the required 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br />; however, due to an administrative oversite, the licensee failed to submit the Special: Report within 30 days as required.
It was determined
.that the licensee's failure-to submit the Special Report as required was an isolated instance of a violation (282/90006-02) of Technical Specifications.
This-violation meets the tests of 10 CFR Part 2. Appendix C, Section. V. A; conseq'ently,i no Notice of Violation will'be issued. This matter is u
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considered closed.
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Violations for Which a " Notice of, Violation" Will Not be Issued The NRC uses the Notice of Violation (NOV) as a standard method for j
formalizing the existence of a violation of a legally binding requirement..
H However, 10 CFR 2, Appendix C, Section V.A has been changed to provide the i
staff with the flexibility not to issue a Notice of Violation for NRC or-
-J licensee identified inspection findings. Such violations are by
definition of minor safety concern.
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One violation of regulatory requirements identified during the inspection
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for which a Notice of Violation will not be issued is discussed in-
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i Paragraph 6.
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Exit (30703)
The inspectors met with the licensee representatives denoted in paragraph'
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-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 i
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during the inspection. The licensee did not identify _ any documents or_-
processes as proprietary.
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