IR 05000498/1989014
| ML20245H266 | |
| Person / Time | |
|---|---|
| Site: | South Texas  |
| Issue date: | 08/02/1989 |
| From: | Bundy H, Seidle W NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION IV) |
| To: | |
| Shared Package | |
| ML20245H260 | List: |
| References | |
| 50-498-89-14, 50-499-89-14, GL-88-17, NUDOCS 8908160389 | |
| Download: ML20245H266 (10) | |
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APPENDIX U.S. NUCLEAR REGULATORY COMMISSION
REGION IV
NRC Inspection Report:.50-498/89-14 Operating Licenses: NPF-76 50-499/89-14 NPF-80 Dockets:
50-498 50-499
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Licensee: Houston Lighting & Power Company (HL&P)
P.O. Box 1700 Houston, Texas. 77001 Tacility Name: South Texas Project (STP), Units 1 and 2 Inspection At: STP, Matagorda County, Texas Inspection Conducted: July 24-28, 1989 Inspector:
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//2[f7 H. F. Bundy, Reactor Inspector, Test Programs Date Section, Division of Reactor Safety Accompanying Personnel:
W. C. Seidle, Chief, Test Programs Section Division of Reactor Safety, July 27-28, 1989
!U Approved:
W. C. Seidle,(Ghief, Test Programs Section Date
Division of Reactor Safety i
Inspection Summary Inspection Conducted July 24-28, 1989 (Report 50-498/89-14; 50-499/89-14)
Areas Inspected: Routine, unannounced inspection of licensee actions to prevent and, if necessary, respond to loss of decay heat ~removai (DHR) as j
described in Generic Letter'(GL) 88-17 for both units and followup on previous
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inspection findings.
Results: The licensee's administrative controls, procedures, equipment, and
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training appeared to satisfy the expeditious action and programmed enhancement recommendations in GL 88-17.
Instrumentation changes and additions had been determined and reflected in procedures and training, but not installed. The
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licensee committed to installation and testing of the revised instrumentation,
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with certain' exceptions, prior to operation:at reduced inventory on eit' er n
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i unit. Provided this is; accomplished, the licensee's program and hardware-
j appeared lto meet the intent of GL 88-17. The diversity and arrangement of.
control:. room' instrumentation was user friendly. The inspector suggested that the licensee consider additional. monitoring.of residual _ heat removal' pump.
performance pursuant to.the guidance in GL 88-17. The training which was being I
provided to plant operators was excellent..The inspector. suggested that l
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. limited training should be considered!.for: maintenance personnel.. Closure.of.
Open item 87.71-01 was. recommended. No violations or deviations were
. identified.
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E DETAILS
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Persons Contacted
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'HL&P
..G.-E..Vaughn.jVicePresident-:NuclearOperations
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- W. H. Kinsey, Plant Manager. -- STP
- S. L. Rosen, Vice President - Nuclear Engineering and Construction.
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- M. R. Wisenburg, Plant Superintendent
- M..A. McBurnett, Department Manager - Support Licensing
- J. W. Loesch, Department Manager - Plant Operations
, T. J. Jordan, Department Manager - Plant Engineering
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- G. L. Parkey, Department Manager - Integrated' Planning and Scheduling
- W;LJ.-Jump, Department Manager - Maintenance
- R. R. Hernandez.. Division Manager - Support Engineering
- D.'R.;Keating Division Manager - Quality Engineering
- C. Ayala,1 Supervising Licensing Engineer W. Harrison, Supervising: Licensing Engineer R. Baker, Supervising Project Engineer.- Mechanical
.J. Constantin. Supervisor Licensed Operator Training
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S. R. Basu, Senior-Consulting Engineer
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R.,Estes Consulting Engineer J. Cook, NSSS Lead Engineer-
'*A. K.;Khosla, Senior Engineer - Licensing G. Sandlin, Senior Engineer - Licensing
.C. T. Bowman. Engineer - Operations Support NRC
- J. E. Bess, Senior Resident Inspector, Unit 1
- J. I. Tapia, Senior Resident Inspector, Unit'2 The inspector also interviewed other licensee employees during the -
inspection.
- Denotes those' attending exit interview on July 28, 1989.
2.
Folicwup on Previous Inspection Findings (92701)
(Closed) Open Item 8771-01, " Safety Injection Piping Flange Misalignment."
This item involved misalignment of Flange NISIFE0927 in the Unit 1 safety injection system approximately 1/4 inch. The acceptance criteria was su
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3/64 inch per foot of flange diameter. Therefore, the misalignment failed the acceptance criterion for an 8-inch line.
This problemLwas dispositioned by the licensee's Nonconformance Report (HCR) 87-0292.
It was concluded that the misalignment was caused
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by thermal growth. After engineering analysis, the joint was reworked to
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have some misalignment at ambient conditions. The flange was tagged to require personnel to review the NCR disposition prior to disassemt'ly. The inspector reviewed a revised as-built drawing and the post rework test satisfactorily completed in accordance with Maintenance Work Request 51-87037822 on December 21, 1987. This item is closed.
3.
Licensee Actions to Prevent ~and Respond to Loss of DHR (TI 2515/101)
The purpose of this inspection was to verify licensee actions to preventL and, if necessary, to respond to loss of DHR during operations with the reactor coolant system (RCS) partially drained. Licensee actions were in response to recommendations contained in GL 88-17, " Loss of Decay Heat Removal." Recommendations were made by GL 88-17 in two categories:
expeditious actions which should be implemented prior to operating in
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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.
For purposes of future reference, the recommendations are briefly paraphrased below (to avoid confusion, the numbers are identical to similar items contained in GL 88-17):
Expeditious Actions (1). Discuss related events and lessons' learned with appropriate plant personnel. Provide training shortly before entering a reduced inventory condition.
(2)
Implement procedures and administrative controls for containment closure in the event of loss of DHR event. This should be accomplished prior to entering a reduced RCS inventory condition for nuclear steam supply systems (NSSSs) supplied by Westinghouse.
(3) Provide at least two independent, continuous temperature indications that are representative of the core exit conditions whenever the RCS is in mid-loop condition and the reactor vessel (RV) head is located on top of the RV.
(4) Provide at least two independent, continuous RCS water level indications whenever the RCS is in a reduced inventory condition.
Indications should be periodically checked and recorded by an operator or automatically and continuously monitored and alarmed.
(5)
Implement procedures and administrative controls that generally avoid operations that deliberately or knowingly lead to perturbations to the RCS and/or to systems that are necessary to maintain the RCS 'a a stable and controlled condition while that RCS is in a reduced cl
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inventory' condition.
If avoidance of perturbations is impossible, compensatory measures should be taken.
(6); Provide at least two available or operable means of adding inventory to the RCS that are in addition to pumps that are a part of.the
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,J normal DHR systems.
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(7)' l Implement procedures-and administrative controls that reasonably
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assure.that both hot legs are not' blocked simultaneously by nozzle Ldams unless.a vent path is'provided that is large enough to prevent pressurization of the upper plenum of the RV.
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(8)' Not appiicable'to STP.
(Applies to units with loop stop valves)
Programmed Enhancements
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(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) at least.two independent temperature measurements representative 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 DHR system is being used for cooling the RCS; and
.(d) visible and audible indications of abnormal conditions in temperature, icvel, 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 DHR systems;
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(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 m
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(c) administrative controls that support and supplement !Se proceduresinitems(a),(b),andallotneractionsidentified in this communication, as appropriate.
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(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 cne 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) -Technical Specifications 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.
(6) RCS Perturbations Reexamine Item (5) of expeditious actions and refine operations as necessary to reasonably minimize the likelihood of loss of DHR.
Comments on the-licensee's actions in response to GL 88-17 are provided below. Unless stated otherwise, they are applicable to both units. 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.- Also, in' addition to reviewing the listed documents and interviewing-appropriate personnel, the. inspec'or walked down the DHR instrumentation installed in the control room.
It should be noted that the residual heat removal (RHR) system is essentially the DHR system as discussed in GL 88-17. The following comments generally relate to licensee commitments contained in a draft revised response to GL 88-17 (Document 3) which superseded previous responses (Documents 1 and 2) in their entirety. The licensee committed to transmittal of this letter to the NRC for review prior to reduced inventory operation for Unit I during the upcoming refueling outage.
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. 7- , > g - ; . . .- , The' inspector reviewed'a l'esson plen (Document 11) and interviewed r licensee l trainers to ascertain licensee responsiveness to Expeditious
?'- Action (1). The lesson plan was comprehensive. 'It addressed L ' -implementation-of.appropriatelicensecprocedures(Documents'4,5,and7).
e It incorporated an excellent vendor video tape on RHR pump vortexing. The
- training was being conducted as a part of the requalification program for
' < , . licensed'and non-licensed' operators. The inspector was-informed that there would be additional ' training for the operating crews just prior to L,J going to reduced inventory op'eration. Additionally, the inspector'was '
N informed that reactor containment building (RCB) and mid-loop coordinators ' h had received training.related to their duties during mid-loop operation
(Document 12). The inspector suggested that the licensee consider-F training maintenance personnel on how their activities could perturb the .' <$ .RCS during; reduced inventory operation.
, [, ' With regard to Expeditious? ction (2) and Programmed Enhancement (2), the A procedures (Documents 4to9)generallysupportedthecommitmentsmadein L: the draft revised response 1to GL'.88-17.
Procedure OPOP03-ZG-0009-requires
,< ~ a closed containment prior to initiating reduced inventory operation.
- Written restoration plans must be' reviewed by' the mid-loop coordinator and e
. approved by the shift supervisor for any containment breaches during reduced inventory operation. 'The mid-loop coordinator will track each
+ proposed breach in;a manual log. The inspector directed a few procedure ' improvement comments to the procedure coordinator for consideration.
,With regard to Expeditious Action (3) and Programmed Enhancement (1)(b), licensee procedures require two trains of core exit temperature-instrumentation with a minimum of five core exit thermocouple (CETs) in ..' each train. The CETs can input to a screen through the qualified display processing system (QDPS) which shows the minimum, maximum, and average temperature for each core quadrant. The CETs also will input to a two pen recorder on Panel CP001 which will record the average of the five highest indicating CETs and the fifth highest CET. The fifth highest pen will .have}a high alarm with a visual and audible annunciator. The above instrumentation was a prerequisite in Procedure OPOP03-ZG-0009. The CET < p# readings can also be displayed on the Emergency Response Facilities Data f
- Acquisition and Display System (ERFDADS).
, v = With,regardTto Expeditious Action (4) and Programmed Enhancement (1)(a), pm
narrow range level-instruments will be added to the RCS hot leg loops A ' . + and C at the beginning of the upcoming refueling outage prior to reduced ' ' inventory-operation. A ' level' transmitter and local sight glass will tap , f into a drain line' on each safety injection line near its connection to the ,m, ' associated hot leg at mid-loop. The reference leg will tap into a primary , ! S samp1_ing line on top.of the hot leg. This will provide a level range from
- the' top of. the hot leg to 31 inches below the center line of the RCS hot
' leg piping., The licensee engineers informed the inspector that the I accuracy capability will be a fraction of an inch. The level transmitter j will provide input to ERFDADS and a narrow range recorder which has a low L , .g level alarm which will annunciate on the control room annunciator board.
N In addition', the reactor vessel water level system (RWLS), which utilizes (>, _ _ _ _ _ _ _ - -. _ - _ _. _. ___--__-______-______-______._-_-__-_-____-___-_--_--_l
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- . -8- . heated junction thermocouple sensors, will be used during the drain down operation. RVWLS senses discrete levels and provides a QDPS. display., The licensee selected Point 3, which is located 4.5 feet below the RV ficnge and 1.5 feet above the top of the hot leg piping, as the defined level at which reduced inventory operation is entered. Point 4 is located at the ! elevation of the top of the hot leg piping. The narrow range water level instruments should begin to come on i,cale at this. point. Point 5 is lccated - at the elevation of the hot leg piping center line and should never.be reached. RVWLS is backed up by a tygon hose level indication system located in a stairwell outside the biological shield wall. The tygon hose will eventually be replaced by a sight glass. ' Procedure OPOP03-ZG-0009 ' required use of all three level instruments.
With regard to Programmed Enhanceinents (1)(c) and (1)(d), instrumentation which was installed, together with instrumentation to be installed and tested' prior to reduced inventory operation, appeared to be generally adequate for monitoring and alarming DHR system performance.
For the first refueling for Unit 1, the licensee intended to monitor RHR pump current on a temporary three pen. recorder with adjustable alarms. The licensee engineers informed the inspector that the permanent installation will incorporate RHR pump current meters with alarms actuating annunciators on the control room annunciator panel. The inspector informed the licensee that GL 88-17 favors recorders over meters for RHR pump current monitoring to provide trending capability. Also, GL 88-17 suggests that pump inlet pressure and pump noise are two useful parameters to monitor for vortexing and cavitation. The~ licensee's program did not incorporate monitoring of these parameters. Also, the licensee was developing an ERFDADS display to monitor important DHR parameters. This display will be located at the operator control console and should be a very useful operating aid.
It will not incorporate RHR pump motor current. The inspector observed that there was generally more than one method of monitoring each DHR performance parameter and the instrumentation was readily visible to the control room operator.
Pursuant to Expeditious Action (5) and Programmed Enhancement (6), Procedure OPGP-03-20-0035 appeared to incorporate sufficient administrative controls to minimize perturbations to the RCS. During reduced inventory operations, it required approval of all work requests and surveillance tests by both the mid-loop coordinator and shift supervisor.
It also incorporated a list of support systems and equipment required for recovery from a loss of RHR including electrical and instrument air systems.
With regard to Expeditious Action'(6) and Programmed Enhancement (3), procedures required two low head safety injection pumps (LHSIPs) or one LHSIP plus one centrifugal charging pump to be available for alternate RCS inventory makeup. Also, Procedure OPOP04-RH-0001 covered the circumstances which require alternate RCS inventory makeup. These pumps are safety grade.
In that GL 88-17 recommends that one of the alternate inventory makeup sources be a high head safety injection pump, the licensee should ensure that the LHSIP will provide adequate pumping
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. + .( N j}, h& eM , h 4h4 ATTACHMENT , -, wt d: ? DOCUMENTS REVIEWED ?v - m' n s , __ , e ' ~ 1.
Letter ST-HL-AE-2877,'itL&P. to. NRC. " Preliminary Response to GL 88-17 - > ,i 1.oss of DHR," dated December 9 1988 p
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Letter ST-HL-AE-2936; HL&P to NRC, " Response to NRC GL 88-17 - Loss of
O DHR;" dated January 17, 1989 L '.. c s 3.s _ > . 3.
'Lettsr ST HL-AE-3097 (Drift), HL&P.to NRC,'" Revised Response to NRC l ~ , GL 88-17' Loss of'DHR," dated July. 24, 1989 . y '4i Procedure OPOP03-ZG-0009, Revision 0, "Mid-Loop Operation," Effective - July 6. 1989.
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Procedure.'0PGP03-Z0-0035, Revision'O,'" Reduced Inventory Operations," ' Effective July!7.-1989 6c Procedure OPMP04-RC-0027,iRevision 0, " Steam Generator. Primary Manway.. Cover and Nozzle Dam Sequencing,",Ef.fective July 17, 1989 7.
Procedure OPOP04-RH-0001, Revision 1,l' Loss of, RHR," Effective July 6, + " ' 1989- ~ 8.
Procedure 1P0P09-AN-01M2, Revision 1, "01MZ-E-1 - RC Mid-Loop Core Exit-Temp'Hi,"s pproved July.6, 1989 a 9.' IPOP09-AN-01M2, Revision 1 "01M2-F-1 - RC Mid-Loop Lv 1 Lo-Lo," approved . July 6,.1989 ' - 10. Memorandum, A. C. McIntyre to M. A. McBurnett, !'RHR Autoclosure Interlock Deletion," dated > June 26 1989.. 11. : Lesson Plan LOT 504'.57.L. Revision 1, " Reduced Inventory Operation," approved July.13.'1989 ' 12 - Attendance Sheet, " Training Meeting for Reactor Containment Building and Mid-Loop Coordinators on Procedure OPGP03-Z0-0035," conducted on July 20.. 1989 by:C. T. Bowman i A - " c l ': ~ o $, ~.).. , ^ ,, c 'i'
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. - k t ' capability under all postulated accident scenarios.
Procedure OPGP03-Z0-0035 required dedicated communications (telephone or sound powered headsets) between the control room and RCB.- In' response to Expeditious Action (7), instructions and guidance have been incorporated in Procedures OPGP03-Z0-0035 and OPM04-RC-0027 to prevent pressurization of the upper plenum of the RV.
Procedure OPMP04-RC-0027 incorporated a data sheet requiring appropriate approvals to assure proper - 't sequencing,of nozzle dam installation and removal.
> .The licensee had incorporated the results of site-specific analyses prepared pursuant to Programmed Enhancement (4) into the appropriate ^ procedures. The instrumentation installation and' response and _ equipment /NSSS interactions and response appeared to be compatible with analyses results'.. Th'e inspector reviewed Document 10 which included a significant hazards evaluation and licensing document change request for deletion of the RHR autoclosure interlock (ACI) pursuant to Programmed Enhancement (5). An , Lattached availability analysis concluded that removal of the ACI would result in a net increase in RHR system availability during. cold shutdown by a factor of 45. Because the RHR system is inside the containment, there would not be a significant increase in.the ssfety risk from an intersystem loss of coolant accident. Because the ACI is not required in
Modes'5 and 6, the-licensee plans to defeat it with a temporary modification during the upcoming outage. The inspector also learned that the licensee is considering a technical specification change request for RHR flow rate reduction in Mode 6.
Currently, there is no minimum RHR, flow rate in Mode 5.
This permits reduction of RHR flow rate to minimize vortexing and potentially recover from air binding in an RiiR pump.
However, in Mode 6 a minimum RHR flow rate'of 3000 gpm must be maintained.
The licensee stated an intent to perform all reduced inventory operation in Mode 5 during the upcoming outage.
No violations or deviations were identified.
4.
' Exit Interview The inspector met with the licensee representatives denoted in paragraph 1 on July 28, 1989, and summarized the scope and findings of this inspection.
Future inspection interests will focus on licensee completion of items noted in this report that were planned or in progress at the time of this inspection.
Proprietary materials provided to the inspectors were returned at the conclusion of the inspection and none of their. contents are reproduced in this report.
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