ML20042G689
| ML20042G689 | |
| Person / Time | |
|---|---|
| Site: | Wolf Creek  |
| Issue date: | 05/09/1990 |
| From: | Bundy H, Seidle W NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION IV) |
| To: | |
| Shared Package | |
| ML20042G686 | List: |
| References | |
| 50-482-90-18, GL-88-17, NUDOCS 9005150294 | |
| Download: ML20042G689 (12) | |
See also: IR 05000482/1990018
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APPENDIX
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'U.S. NUCLEAR REGULATORY COMMISSION
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REGION IV
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NRC Inspection Report: .50-482/90-18.
Operating License': '50-482
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Docket: 50-482
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.Licenhee: Wolf Creek Nuclear Operating Corporation'(WCNOC)
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P.O.' Box 411
Burlington, Kansas 66839-
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- Facility Name: -Wolf Creek Generating Station (WCGS)
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. Inspection At: WCGS,'Burlington, Kansas
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' Inspection Conducted: . April 23-27, 1990
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. Inspector:
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H. F. Bundy, Reactor Inspector, Test Programs
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Section, Division of Reactor Safety.
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- Accompanied
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W.-C. Seidle, Chief, Test Programs 1Section-
Division of' Reactor Safety (April .26-27)
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~ Approved:-
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W. C. Seidle, Chief, Test Programs Section
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Division of Reactor: Safety
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' Inspection Summary
Inspection Conducted April 23-27,1990(' Report 50-482/90-18)
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Areas Inspected: Routine, announced inspection of licensee actions on previous:
inspection fiiIdings, programmed enhancements in res
Letter:(GL)l88-17 [ loss of decay heat removal:(DHR)ponse, to Generic .
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measurement of reactor coolant system (RCS) leak rate.
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'-Results: The licensee's corrective action program fo_r emergency diesel
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. generator. (EDG) maintenance, which was ! instituted in response to .
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Violation:482/8839-02,;was functioning as evidenced by self-identification of a
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inumberr of- maintenance problems. :However, a sizable bEcklog of maintenance work
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. requests was noted. LThe: violation will: remain open pending replacement of the
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'.fuelJoil lines; which were the subject of the violation, with flexible tubing
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-to avoid further;vibrationally induced failures.
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9005150294 900509
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ADOCK 0300o482
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The licensee's programmed enhancements satisfied the intent of GL 88-17. The
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p.CS-level instrumentation was accurate and had a high level of redundancy. The
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. cperators were knowledgeable and appeared comfortable with DHR monitoring-
capabilities. The licensee was developing a DHR-performance computer. screen
which should enhance monitoring capability. Previous _ inspector comments on
procedures and training had been resolved. Lesson plans were' excellent, and
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timely trainin
Instrumentation for monitoring residual
heatremoval(ghadbeenaccomplished.RHR) pump cavitation was marginal. The license
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intention 1to' evaluate the installation of improved noise monitors and low RHR
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pump' motor: current alarms.
The inspector verified the -licensee's calculations for RCS leak rates for a
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- surveillance performed on March 8,1990.
No violations or deviations were identified.
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DETAILS
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PERSONS CONTACTED
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- B.-D. Withers, President
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- J. A.; Bailey, Vice President, Nuclear Operations
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- *F. T. Rhodes, Vice President,' Engineering and Technical Support
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'*G. D. Boyer, Plant Manager
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- 0. L. Maynard, Manager, Regulatory Services
- C. E. Parry, Manager, Site Quality
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- M. G. Williams, Manager, Plant Support
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- J.. A. Zell, Manager, Training
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- R. W. Holloway, Manager, Maintenance and Modifications
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. *J.M.-Pippin, Manager,NuclearPlantEngineering(NPE)
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- J. Weeks, Manager,- Opera _tions
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J. Stamm, Manager, System Engineering
'C..W.. Fowler,' Manager, Instrumentation and Control
- M. E. Dinglor, Manager, NPE-System
- R.- S.LBenedict, Manager, Quality Control
- *W. M. Lindsay,' Manager, Quality Assurance
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- D..G. Moseby, Supervisor, Operations
- H. L._ Stubby, Supervisor,' Technical Training
-'*R. K. Lewis, Supervisor,'Results Engineering
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- H. K. Chernoff, Supervisor,= Licensing
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- S. G.-Wideman,_ Senior ~ Engineering Specialist
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B. Smith,- Supervisor, Modifications
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G. R. Smith, Licensed Supervising Instructor
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S. C. Hopkins, Engineering' Specialist III_
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J. E. North, Engineering Specialist III
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.D. Kruse, Maintenance Engineer
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E. Weissloar, Colt Representative
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M..E. Skow, Senior Resident Inspector
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The_ inspector also interviewed other licensee employees-during the inspection.
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- Denotes those attending the exit interview on April 27, 1990.
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LICENSEE ACTIONS ON PREVIOUS-INSPECTION FINDINGS-(92702).
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(0 pen) Violation 50-482/8839-02, " Failure to Take Adequate Corrective Action to
Prevent-Failure of an Emergency Diesel Generator (EDG) Fuel Oil Line." This
violation-involved failure of a fuel oil accumulator fill / vent line on EDG B on
' November- 27, 1988. A similar failure of the identical line for EDG A occurred
on December 4, 1986. There was no evidence that any actions had been taken to -
prevent the second failure._ In addition to replacing the broken line with
different material, the licensee performed walkdowns on fluid lines for both
EDGs to identify further vibrational stress and fretting problems. Softeners
were added to-existing supports to isolate vibration and decrease the
possibility of rubbing holes _in tubing in accordance with an engineering-
evaluation. The inspector reviewed supplemental work instructions dated
February 7, 1989, which included appropriate EDG acceptance criteria developed
in response to Programmatic Deficiency Report OP.89-021.
The inspector reviewed Memoranda MA 89-0182 and MA 89-0281 relating to EDG
training for the emergency diesel engineer at a similar facility and at the
vendor's plant. The inspector reviewed successful EDG start logs for
alternating quarterly 24-hour runs in accordance with Procedure STS KJ-005A,
Also, data indicating successful 24-hour runs in accordance with
Procedure STS MT-016 for each EDG before and after inspection during refueling.
Outage-4 was reviewed.
During a.walkdown'of EDG A, the inspector observed a work request tag.on a
fluid line identified for replacement and remuting. The maintenance engineer
stated that he had found fretting on the line from vibrational contact with a
structural component. Also, several work request tags for leaking fluid line
gaskets and connections were observed. Several of these had 1989 dates.
Examples were 31012,_32033, and 45351. Extensive use of absorbent cloths was
observed.
During the walkdown of EDG B, the inspector observed that the exhaust manifold
had been-removed. The system engineering manager stated that a fire involving
RTV sea'lant,' which had been applied to stop leaks, had occurred during a
postmaintenance run on April 17, 1990.
It turned out that RTV sealant was not
satisfactory for that application. Subsequent to replacement of the RTV
sealant, a.24-hour run had been completed on April 23, 1990. However,
extensive manifold leaks were observed and the decision was made to replace all
exhaust maniiold seal material. The inspector observed that another extended
run might be appropriate and the plant manager informed him that it was being
evaluated.
The system engineering manager stated that they were going to replace the fuel
-oil line that was the subject of the violation on both EDGs with flexible
tubing because:of continued observation of high vibrational stress. He had
also authorized use of Swagelock fittings, stainless tubing, and Teflon tape to
reduce leakage as lines are replaced. A vendor representative was present
during the walkdown and discussions and indicated his approval of licensee
actions.
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Although EDG maintenance problems' continued to exist, the licensee's revised
corrective action. program appeared to.be etfectively resolving them. However,
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this violation will remain open pending installation of the flexible tubing in.
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the fuel 011' fill / vent lines.
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3.
PROGRAMMED ENHANCEMENTS IN RESPONSE TO GL 88-17 - LOSS OF-DECAY HEAT-
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- REMOVAL (TI 2515/103)
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3.1 GL 88-17 Recomeridations and Inspection Scope
GL :S8-17 provided recomended. licensee actions to prevent and, if necessary, to
respond to loss of DHR during operations with the RCS partially drained.
Recomendations were made by GL 88-17'in two categories:
Expeditious' actions, which should be implemented prior to operating in a
reduced-inventory condition, and
Programmed enhancements, which should be developed in parallel with the
expeditious actions and may replace, supplement, or add to the expeditious
actions.
NRC's review of the licensee's expeditious actions was documented in NRC
Inspection Report 50-482/89-17. The status of the licensee's programmed
enhancements was also-discussed. The purpose of this inspection was to follow
up on NRC Inspection Report 50-482/89-17 comments and concerns and ascertain
completion of programmed enhancements. For the purpose of-future reference,-
the programmed enhancement recommendations are briefly paraphrased below (to
avoid confusion, the: numbers are identical to similar items contained-in
GL88-17):
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Programmed Enhancements
(1) Instrumentation
Provide reliable indication of parameters that_ describe the state of the-
RCS and the performance of systems normally used to cool the RCS for both
normal and accident conditions. At a minimum, provide the following-in-
. the control room:
(a) Two independent RCS level indications;
(b)-Atleasttwoindependenttemperaturemeasurementsrepresentative
of the core exit whenever the RV head is located on top of the.
RV;
(c) The capability of continuously monitoring DHR system performance
whenever a OHR system is being used for cooling the RCS; and
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(d) Visible and audible indications of abnormal conditions in
temperature, level, and DHR performance.
- (2) Procedures
Develop and implement procedures that cover reduced inventory
operation, and that provide an adequate basis of entry into a reduced
inventory condition. These include:
=(a) Procedures that cover normal operation of the NSSS, the
containment, and supporting systems under conditions for which
cooling would normally be provided by DilR systems;
(b) Procedures that cover emergency, abnormal, off-normal,-or the
equivalent operation of the NSSS, the containment, and
supporting systems if an off-normal condition occurs while
operating-under conditions for which cooling would normally be
provided by DHR systems; and
(c) Administrative controls that support and supplement the
proceduresinitems(a),(b),andallotheractionsidentified
in this communication, as appropriate.
(3) Equipment
(a) Provide equipment of high reliability for cooling the RCS and
avoiding loss of RCS cooling;
(b) Maintain equipment available to mitigate loss of DHR or loss of
RCS inventory should they occur including at least one high
pressure injection pump and one other system, each sufficient to
keep the core covered; and
(c) Provide adequate equipment for personnel communications
involving activities related to the'RCS or systems necessary to
maintain =the RCS.in a stable and controlled condition.
(4) Analyses
Conduct analyses to supplement existing information and develop a
basis for procedures, instrumentation installation and response, and
equipment /NSSS interactions and response.
(5) TechnicalSpecifications(TS)
Technical Specifications that restrict or limit the safety benefit of
the actions identified in this letter, should be identified and
appropriate changes should be submitted.
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(6) RCS Perturbations
P,eexamine item (5) of expeditious actions and refine operations as
necessary to reasonably minimize the likelihood of loss of DHR.
3.2
Licensee's Actions in Response to GL 88-17 Programed Enhancement
Recomendations
The inspector's coments on the licensee's actions are provided below. The
Attachment is a tabulation of related documents reviewed by the inspector.
When a document number is cited below, it will be the number assigned in the
Attachment.
In addition to reviewing the listed documents and interviewing
appropriate personnel, the inspector walked down recently installed RCS level
instrumentation.
In general, recent procedure revisions together with training
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conducted just prior _to.the current refueling outage satisfactorily resolved
inspector concerns and coments discussed in NRC Inspection
Report 50-482/89-17. The newly installed level instruments had the required
independence and a high degree of redundancy. They were also user-friendly.
Operations personnel reported.that they were highly acccrate when compared to
the existing Tygon hose. Residualheatremoval(RHR)pumpcavitation
monitoring-capability was marginally acceptable. Operators were knowledgeable
and comfortable with DHR monitoring capabilities. The inspector's coments on
the licensee's actions in response to the programed enhancement recomendation
as comitted to in Document 1 follow.
3.2.1
Instrumentation
The-inspector walked down RCS-level instruments, which were recently installed
in accordance with Document 2.
Thtre were two redundant pairs of instruments.
Each pair had an independent pressure tap at the RTD bypass manifold off the
RCS Loop 1 hot leg, Each pair also had an independent reference pressure tap
off the pressurizer. For each pair, there was a wide and narrow range level
indicator. The scales were as follows:
Narrow range: 5-55 inches
Wide range: 5-265 inches
They were calibrated to indicate 15 inches when operating at half loop. The
minimum operating level was administrative 1y established at 20 inches.
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narrow range transmitter could actuate high and low level alarms.
The inspector noted that the principal means for monitoring RHR pump cavitation
in the control room was noise monitors. This method had a shortcoming in that
the microphones were known to pick up other background noise, e.g., air
conditioners and work activities. The operations supervisor stated that he was
working on a proposal to install more reliable noise monitors.
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It was possible to monitor RHR pump motor current.on computer points. However,
low current alarms were not installed. Because low current is an indication of
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pump cavitation, the-licensee stated an intention to evaluate the' installation
of-' alarms. .
The DHR performance computer screen discussed in NRC Inspection
Report 50-482/89-17 was not functional. The inspector was informed that
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development was continuing and that it would definitely be available when the
new plant computer is installed in the near future. Other instrumentation
capabilities were as described in NRC Inspection Report 50-482/89-17.
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Procedures-
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By review of Documents 3-8 and interviews, the inspector ascertained that'-
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procedural concerns discussed in NRC Inspection Report 50-482/89-17 had been
resolved and appropriate retraining had been accomplished. Lesson plans were.
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excellent and records indicated timely training of appropriate personnel. The.
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licensed supervising instructor stated that simulator training had been covered
on a loss of cooling accident during shutdown (Braidwood event). During the
review of Procedure GEN 00-007, the inspector noted that' containment closure is
accomplished by. performance of Procedures STS.GP-001 and STS'GP-007 prior to
going to reduced -inventory.
It appeared that the licensee established this
requirement to avoid developing a procedure for fast containment closure. The-
inspector. advised-the training manager that the reduced inventory containment
closure requirement should be emphasized during training to avoid an-
inadvertent opening of the containment.
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Equipment
As discussed'in NRC Inspection Report 50-482/89-17,.the licensee's equipment
-availability appeared adequate to meet the intent of GL 88-17. The licensee
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processed a TS change to delete the requirement for tagging out the safety-
injection'(SI) pump-during reduced inventory operation.
3.2.4
Analyses
The inspector verified that procedural and administrative control requirements
were adequately supported by analyses by reviewing Documents 9-16. -These-
documents supported the assumptions in Procedure GEN 00-007 and technical data
, was appropriately translated to the procedure. Documents 9 and 16 calculations'
supported using ef tNr e SI pump or a centrifugal charging pump for independent
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inventory makeup;
Doetm r.1 10 provided a basis for removing the crossover leg
plenum sife s hway prior to the hot leg side manway cover. This is counter to
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guidannC in URC IN 88-16, but consistent with Westinghouse WCAP-11916. The IOM
states that IN 88-36 did not consider the " spill" penalty.
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3.2.5
TS Changes
Documents 17 and 18 comprised the request for and issuance of TS enhancements
related to loss of DHR, respectively. The TS changes implemented consisted of
the following:
Adding a note to.TS 3/4.4-6 to add criterion for ensuring reactor vessel
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water level is above the vessel flange before the running RHR pump can
. intentionally be stopped while in Mode 5 with the reactor coolant loops
not filled.
Revising TS 4.9.8.1 and 4.9.8.2 to decrease required flow rate of the
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- running RHR pump.
Revising TS 3.5.4 mode applicability to have the SI pumps immediately
.available should.RHR cooling be lost when reactor coolant level is below
the vessel flange.
' A change to delete the RHR automatic closure interlock was to be addressed in a
future submittal. The above changes were appropriately reflected in Procedure.
GEN 00-007.
3.2.6
RCS Perturbations
.By review of Documents-3-8 and interviews with operations.and training
pers0nnel, the inspector ascertained that appropriate precautions had-been
included in.the procedures to avoid RCS perturbations during reduced inventory
operations. Also, training had emphasized avoidance of RCS perturbations.
No violations or deviations were identified.
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INDEPENDENT MEASUREMEl!T OF RCS LEAK RATES (61728)
--To verify satisfaction of TS requirements and the adequacy of the licensec's
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-calculational technique for determining RCS leak rates, the inspector
independently verified the results of the leak rate surveillance performed on
March 8,1990(Attachment, Document 19). The inspector used the NRC computer
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program for. determination of RCS leak rates (RCSLK9) which is discussed in
NUREG-1107.1 The results were as follows.
Identified
Unidentified-
STSBB-004-
0.6334 gpm
0.1911 gpm
RCS LK9-
0.69 gpm
0.16 gpm
- The results satisfied TS criteria of 10 gpm-identified and 1 gpm-unidentif wd. -
The-inspection criterion for results to be within 0.2 gpm was also satisfied.
No_ violations or deviations were identified.
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EX1T' INTERVIEW
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The inspector met with licensee representatives denoted in paragraph 1 on
April 27, 1990, and summarized the scope and findings of this inspection. The
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reviewed by, the inspector. during this inspection.
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ATTACHNENT
DOCUMENTS REVIEWED
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1.
Letter WM 89-0041, WCNOC to NRC, "GL 88-17 - Loss of _DHR," dated
February 2,1989
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PlantModificationRequest(PMR)02937, Revision 3,"Mid-LoopIndependent
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Level Indication," dated April 11, 1990.
3.
Procedure GEN 00-007, Revision 12, Procedure Change MA 90-056, "RCS Drain
Down," approved April 18, 1990.
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Procedure OFN 00-015, Revision 8 " Loss of Shutdown Cooling (RHR),"
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approved April 4, 1990.
LessonPlan(LP)093,) Revision 000."0FN00-015. Revision,andLossof
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Shutdown Cooling (RHR ," approved December 28, 1989.
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LP110, Revision 000, "RHR System / Loss of Shutdown Cooling," approved
January 2,1990.
7.
LP093', Revision 003, " Refueling Concerns," approved January 3,1990.
8.
LP114, Revision 000, " Half-Loop Operation," approved-January 11, 1990.
9.
InterofficeMemorandum(10M)NS88-1332
T. J. Garrett to K. R. Peterson,
" Response to Action item No. 6 of 'NRC GL 88-17," dated October 15, 1988.
10.
IOM NS 88-1181, T. J. Garrett to C. M. Estes, " Basis for Recommended SG
Primary Side Manway and Nozzle Dam Removal and Installation Sequence for
-_Mid-loop Operations," dated November 1,1988.
11 '. Calculation SA-88-026, Revision 0, " Predicted Coolant Level Variations in
the RCS During Mid-Loop Operations," dated November 15, 1988.
12.- Calculation SA-87-019, Revision 0, " Loss of RHR at Half Pipe Using 1979
Decay Heat Data and RCS Pressurization," dated September 4,1987.
13. Calculation SA-87-018, Revision 0, " Loss of.RHR at Half Pipe using 1979
ANS Decay Heat Data," dated September 2,1987.
14. Calculation SA-87-021, Revision 0, " Minimum Allowed RHR Flow to Maintain
RCS less than 140*F When RCS is at Half Pipe," dated September 24, 1987.
15. Calculation SA-89-009, Revision 0, "The Minimum RHR Flow Requirements for
OHR During Mid-Loop Operation," dated May 23, 1989.
16. Calculation SA-88-023 Revision 0, " Venting Requirements for Mid-Loop
Operation With SG Hozzle Dams in Place."
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17. Letter WM 89-0264 WCNOC to NRC, ' Revision to TS 3.4.1.4.2, 3.5.4,
4.9.8.1, and 4.9.8.2 - RHR Flow Rate and SI Pump Availability," dated
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November 30.-1989.
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18. . Letter,- NRC'to WCN00, " Amendment No. 35 to Facility Operating' License
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No.- NPF-42," dated February 21, 1990.
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19. Procedure STS BB-004, Revision 5, "RCS Water Inventory. Balance," performed
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on March 8,'1990.
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