IR 05000413/1989025: Difference between revisions

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{{Adams
{{Adams
| number = ML20248B705
| number = ML19325E154
| issue date = 09/25/1989
| issue date = 10/26/1989
| title = Insp Repts 50-413/89-25 & 50-414/89-25 on 890801-28 & 0912-15.Violations Being Considered for Enforcement.Major Areas Inspected:Two Events Re Overspeeding & Tripping of Auxiliary Feedwater Pump
| title = Forwards Summary of 891012 Enforcement Conference Re Insp Repts 50-413/89-25 & 50-414/89-25 & Unit 2 Turbine Driven Auxiliary Feedwater Pump Overspeed Trip.List of Attendees & Handout Encl
| author name = Lesser M, Orders W, Shymlock M
| author name = Ebneter S
| author affiliation = NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION II)
| author affiliation = NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION II)
| addressee name =  
| addressee name = Tucker H
| addressee affiliation =  
| addressee affiliation = DUKE POWER CO.
| docket = 05000413, 05000414
| docket = 05000413, 05000414
| license number =  
| license number =  
| contact person =  
| contact person =  
| document report number = 50-413-89-25, 50-414-89-25, NUDOCS 8910030268
| document report number = NUDOCS 8911020120
| package number = ML20248B690
| document type = CORRESPONDENCE-LETTERS, NRC TO UTILITY, OUTGOING CORRESPONDENCE
| document type = INSPECTION REPORT, NRC-GENERATED, INSPECTION REPORT, UTILITY, TEXT-INSPECTION & AUDIT & I&E CIRCULARS
| page count = 53
| page count = 18
}}
}}


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=Text=
=Text=
{{#Wiki_filter:___ ____-_-___________ -
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OCT e 61989 j
,
fll Docket Nos. 50-413, 50-414 L
License Nos. NPF-35, NPF-52 l
t i
Duke Power Company
 
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UNITED STATES
$~
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c9 NUCLEAR REGULATORY COMMISslOM
ATTN: Mr. H. B. Tucker, Vice President
'
Nuclear Production Department
;
422 South Church Street
;
Charlotte, NC 28242 i
Gentlemen:
!
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:
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SUBJECT:
ENFORCEMENT CONFERENCE SUMMARY j
(NRC INSPECTION REPORT N05, 50-413/89-25 AND 50-414/89-25)
;
,
This letter refers to the Enforcement Conference held at our request on i
October 12, 1989.
 
This meeting concerned activities authorized for your
;
Catawba facility.
 
The issues discussed at this conference related to the
;
Unit 2 turbine driven auxiliary feedwater pump overspeed trip and the
!
mispositioning of Unit 2 Auxiliary Feedwater system control board switches and f
assured suction supply valve closure.
 
A list of attendees, a summary, and a i
!
copy of your handouts are enclored.
 
We are continuing our review of these issues to determine the appropriate enforcement action.
 
l f
In accordance with Section 2.790 of the NRC's " Rules of Practice," Part 2, Title 10, Code of Federal Regulations, a copy of this letter and its enclosures
[
will be placed in the NRC Public Document Room.
 
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Should you have any questions concerning this matter, please contact us.
 
!-;
 
Sincerely,
'I 06=
Et y_A l
H>mt^% CAW.Cs & V
\\
Stewart D. Ebneter i
Regional Administrator Enclosures:
i
.
.
REGION 88
1.
 
List of Attendees
'
2. ' Enforcement Conference Summary
:
3.


j 101 MARIETTA STREET, N.W.
AFW Suction Supply Valve Closure
-!
Handout i
4.


Turbine Driven AFW Pump Overspeed
:
Handcut j
t cc w/encis:
;
T. B. Owen, Station Manager
;
Catawba Nuclear Station l
P 0.' Box 256 i
Clover, SC 29710
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(cc w/encls cont'd - see page 2)
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8911020120 891026 ADOCK03OOg3 DR p
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ATLANTA, GEORGI A 30323
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Duke Power Company
Report Nos.:
50-413/89-25 and 50-414/89-25 Licensee: Duke Power Company 422 South Church Street Charlotte, N.C.


28242-Docket Nos.: 50-413 and 50-414 License Nos.: NPF-35 and NPF-52 Facility Name: Catawba Units 1 and 2 Inspection Conducted: August 1, 1989 - August 28, 1989, and September 12, 1989 - September 15, 1989 Inspector:,
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cc w/ enc 1st Cont'd
M.T. Orders,SenioyResidentInspector Date/ Signed Inspector:
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Peter G. LeRoy Nuclear Production Department
9h8I9
,
"M.S.' Lesser,ResifentInspector Gate' Signed
Duke Power Company t
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Approved by:
P. O. Box 33189 Charlotte. hC 20241 l
J W M. B. Shymlock, Chief Oate/ Signed Reactor Projects Section 3A Division of Reactor Projects SUMMARY Scope:
 
This special resident inspection was conducted on site' inspecting two events.
A. V. Carr. Esq.
 
l Duke Power Company l
422 South Church Street i
Charlotte. NC 28242
{
J. Michael McGarry. !!!. Esc.


The first event concerned the Unit 2 turbine driven auxiliary feedwater pump (CAPT) which oversped and tripped during surveillance testing,^ was returnec' to service without adequate corrective action, and subsequently oversped during a test one week later.
l Bishop. Cook. Purcell and Reynolds
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1400 L Street. NW i
Washington. D. C.


The second event, which occurred during the performance of a
20005 i
i North Carolina MPA-1 L
3100 Smoketree Ct.. Suite 600
,
P. O. Box 29513
!
Raleigh. NC 27626-0513 Heyward G. Shealy. Chief i
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Bureau of Radiological Health South Carolina Depart:nent of Health
,
,
and Environmental Control l
2600 Bull Street l
Columbia. SC 29201
!
t Richard P. Wilson. Esq.
Assistant Attorney General
:
S. C. Attorney General's Office
!
P. O. Box 11549 i
Columbia. SC 29211
!
i Michael Hirsch Federal Emergency Management Agency
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North Carolina Electric
:
Membership Corporation
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'
piping flush procedure on Unit 2 involved the mispositioning of Auxiliary Feedwater system control board valve switches which control the realignment of both Unit 2 motor driven auxiliary feedwater suctions to Nuclear Service Water.
3400 Sumner Boulevard
-
s i
P. O. Box 27306 Raleigh. NC 27611 F
i Karen E. Long i
Assistant Attorney General
.
N. C. Department of Justice
!
P. O. Box 629 Raleigh. NC 27602
)
(cc w/ enc 1s cont'd - see page 3)
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Results: Two apparent violations are currently.being considered for escalated enforcement.
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Duke Power Company


The first involves the failure to take adequate corrective action in response to a failed surveillance test on. the Unit 2 turbine driven auxiliary feedwater pump.
j L
oct 2 s ses


A maintenance work request was not written to document authorization to perform work, maintenance, and retest activities conducted on this component.
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cc w/ enc 15: Cont'd


Actual work conducted failed to identify the root cause of the overspeed.
L Saluda River Electric i
Cooperative. Inc.


An adequate evaluation of the failure to justify operability was not performed prior to returning the pump to service.
i P. O. Box 929
'
,
i Ladrons. SC 29360


This resulted in the potential inoperability of the CAPT for a period 891003o268 890 2,,
PDR ADOCK 0500
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u
S. S. Kilborn. Area Mana9er i
(<
Mid South Area ESSD Projects
)
Westinghouse Electric Corporation i
MNC West Tower - Bay 239
-
I P. O. Box 335
 
l Pittsburg. PA 15230
 
<
:
l County Mana9er of York County l
York County Courthouse York. SC 29745 i
Piedmont Municipal Power Agency l
100 Memorial Drive Greer. SC 29651 State of South Carolina r
bec w/encis:
K. N. Jabbour. NRR Document Control Desk NRC Resident Inspector
'U.S. Nuclear Regulatory Commission Route 2. Box 179-N York. SC 29745 Ril:0,RP RI!
P RI
.P R1 :
Rll O P spr
.Shymlock AHerdt iJ ns TReyes 10t#/89 10/3(/89 10/jf/89 10/fs789 10/,3-{ /89 i
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ENCLOSURE 1
'
LIST OF ATTENDEES U.S. Nuclear Regulatory Commission j
i S. D. Ebneter. Regional Adminit,trator
,
'
A. Gibson. Acting Deputy Regional Administrator
'
E. W. Merschoff. Deputy Director. Division of Reactor Safety (DRS)
G. R. Jenkins. Director. Enforcement and Investigation Coordination Staff
'
(EICS)
;
'
M. B. Shymlock. Section Chief. Division of Reactor Projects (DRP)
'
K. N. Jabbour. Project Manager. Office of Nuclear Reactor Regulation (NRR)
I W. T. Orders. Senior Resident Inspector. Catawba. DRP M. S. Lesser. Resident Inspector. Catawba. DRP
,
B. R. Bonser. Project Engineer. DRP
!
B. Uryc. Enforcement Coordinator. ElCS i
Duke Power Company
!
!
J. W. Hampton General Manager. Nuclear Relations T. D. Owen. Station Manager. Catawba R. Gill. Manager Regulatory Compliance i
R. G. Morgan. Regulatory CCTpliance. General Office R. N. Casler. Operations Superintendent. Catawba
,
R. M. Glover. Compliance Engineer. Catawba
'
W. R. McCollum, Maintenance Superintendent. Catawba R. A. Jones. Manager. Maintenance Engineering Services
'
'
.,
t W. R. Tomlinson. Maintenance Engineering Services G. B. Swindlehurst. Design Engineering. General Office
:
D. M. Cameron. Project Engineer. North Carolina Municipal Power Agency l
:
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i FNCLOSURE 2 l
ENFORCEMENT CONFERENCE SUMMARY I
On October 12. 1989, representatives f rom Duke Power Company (DPC) met with the NRC in the Region !! office in Atlanta. Georgia to discuss two Auxiliary i
Feedwater (CA) system issues.
The first issue concerned mispositioning of CA


l
!
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system control board valve switches which control the realignment of both
'
Unit 2 motor driven CA pump suctions to Nuclear Service Water.


in excess of the allowed action statement. During a portion of this time, one of two motor driven auxiliary feedwater pumps was also inoperable.
The second
!
I issue concerned a Unit 2 turbine driven CA pump overspeed trip and subsequent return to service without adequate corrective action.


The second apparent violation, which occurred during the performance of a piping flush procedure on Unit 2, involved the failure to assure.
Following opening remarks by Stewart Ebneter. NRC Rll Regional Administrator.


that the control board switches for the valves which automatically
'
)
DPC gave a presentation (Enclosures 3 & 4) on the CA issues.
realign the suction of both Unit 2 motor driven auxiliary feedwater


pumps to the Nuclear Service Water (RN)' system, the-assured source of.
T. B. Owen.


J makeup water, remained 'in the AUT0 position.
Catawba Station Manager. introduced OPCs presentations. The first presentation
!
covered the Unit 2 CA pump inoperability due to mispositioning of the control i
board switches and included a secuence of events, weaknesses identified /
!
corrective actions taken. safety significance. a suunary and concluding remarks.
 
The second presentation covered the Unit 2 turbine driven CA pump overspeed trip and included a physical description of the turbine driven pump, a sequence of events, root cause/immediate and long-term corrective actions. an l
analysis of system performance, a summary. and closing remarks.


This rendered both trains of auxiliary feedwater inoperable.
I The NRC closed the meeting by stating that DPC's presentations had served to enhance Region II's understanding of the issues and DPC's corrective actions.


A significant contributor to this event. was an inadequate flush-procedure which failed to assure that the control board. switches for the valves remained in the
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AUTO position.
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[NCLOSURE 3
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AOBNDA
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t NRC RMPORCBMBNT CONFSRBMcB
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UNIT 3 AUwrn.tAaY FREDFUMP IMOpan ARRt.RTY DUE TO CLAM FLUSE AND ASSURSD SUCTION SUFFLY VALVE CLOSURE
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i DUES F0WER COMPANY l
CATAWBA NUCLEAR STATION i
OCTOSSR I3,!$89 j
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0FBNING Rau AaEn T.8.OWBN i
STATION MANAORR = CNS
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SSQUENCE OF BVBNTS R. N. CASLER
-
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I WBARNESSES ADENTIFIED/
R. N. CARLER
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conasCTIVs ACTIONS TAERN SUPERINTENDENT OF OPERATIONS f
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SAFSTY SIGNIFICANCE O. B. SWINDLREURST DaSION sNORNaamrNO
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SUuuAmY T.B.OWBN STATION MANAORA = CMS
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CLOS 8HO Rau Aara J. W. MAMPTON MANAORE OF NUCt. EAR amt.4TIONS j
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NDeunAL ALIGNISEffT l
RN-NUCLEAR SERVICE WATER l
CA-AUX.FEEDWATER RC-CONDENSER CIRCULATING WATER N
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UPPEM SURGE TANK
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S REPORT DETAILS 1.
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AUX.FEEDWATER f
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EL 642'
UST CONDENSATE STORAGE TANK (


Persons Contacted I
es.c00 GALLONS EL 633'
Licensee Employees j
(CA CST
I
~
*H. Barron, Operations Superintendent
.
.l W. Beaver, Performance Engineer i
,
**R. Casler, Operations Superintendent T. Crawford, Integrated. Scheduling Superintendent
j 42,500 GALLONS i
***J. Forbes, Technical Services Superintendent
)
***R. Glover, Compliance Engineer T. Harrall, Design Engineering R. Jones, Maintenance Engineering Services Engineer F. Mack, Project Services Engineer j
.
W. McCollough, Mechanical Maintenance Engineer
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W. McCollum, Maintenance Superintendent
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***T. Owen, Station Manager J. Stackley, Instrumentation and Electrical Engineer B. Caldwell, Station Services Superintendent Other licensee employees contacted included technicians, operators, mechanics, security force members, and office personnel.
EL 563*-4" i
E L 557*-1 ~
170,000 GALLONS I


Accompanying Personnel
i HOTWELL
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* M. Shymlock, Section Chief, Division of Reactor Projects NRC Resident Inspectors
 
***W. Orders
RC
***M. Lesser Attended exit interview August 24, 1989
*
*
Attended exit interview September 15, 1989
!
**
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.i Attended both exit interviews on August 24, 1989 and i
sem,
***
,
September 15, 1989 2.
TRAIN i
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l AUX. FEEDWATER PUMPS


Turbine Driven Auxiliary Feedwater Pump Event a.
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Executive Summary
"
)
,
On July 31, 1989 unit 2 was operating at 98% power and.in the process of performing a Technical Specification surveillance on the Turbine
,
.
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Driven Auxiliary' Feedwater. Pump (C/ PT) in accordance with-PT/2/A/4250/06, Auxiliary Feedwater. (CA) Pump Head and Valve
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Verification.
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2
 
4


The pump initially failed the surveillance when it
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tripped on overspeed.
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The test was successful on the fourth start, however, no corrective action was performed.
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The licensee declared
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the pump. operable based upon completing ~ the surveillance test.
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On August 7, the CAPT again oversped during testing which raises the question of its operability when returned to service on July 31, 1989.
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System Description and Design Basis The Auxiliary Feedwater System (CA) assures sufficient feedwater supply to the steam generators (S/G),.in the event of loss of the Condensate /Feedwater System, to remove energy stored in the core and primary coolant.
.
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The CA System may also be required in some other circumstances such as-evacuation of the main control room or cooldown-after a loss-of-coolant accident for a small break', including maintaining a water level in the steam generators following such a break.
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laar_e.


Three CA pumps are provided, powered from separate and diverse power sources.
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Two full capacity retor driven ~ pumps are powered from two separate trains of emergency-on-site electrical power, each normally supplying feedwater to two steam generators.
,,,,,,,
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CPCS nl ACCW


One full capacity turbine driven pump, supplying feedwater to the B&C steam generators, is driven from steam contained in either the B or C steam generators.
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Sufficient diversity and redundancy is provided such-that the CA System is capable of delivering the minimum required flowrate to effective steam generators during all modes of operation.
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The CA System is capable of delivering the required flowrate to effective steam generators at a pressure corresponding to the lowest S/G safety valve set pressure'plus 3% accumulation.
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Standards for nuclear safety related systems are met-for the CA System except for the condensate quality feedwater sources.
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The Standby Nuclear Service water pond serves as the ultimate long term safety related source of water for the system.
- - -,,
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The mot"r driven pumps will automatically start and provide the
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minimum required feedwater flow within one minute following any of
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t SEQUENCE OF EVENTS f-i O kN to CA Piping Clan Flush PT in progress o CA Pump Turbine steam supply and water suction valves are closed during this PT o 0ATC places 2CA15A and 2CA18B switches to "CLOSE" o About 5 minutes later, DATC notices 1.47 Panel lights for
"A" and "B" train
-
CA lit
'
'
the following conditions:
o Having a light is not always an accurate operability indication o Some PT's cause panel lights to come on o 0ATC needed STA assistance to determine reason for lights o STA was not in control room at that time o STA assistance is normally required o CATC was sure lights were caused by the CA activities o 0ATC did not fully understand the lights but did not immediately consider them' abnormal e
(1) Two out of four low-low level alarms in any one of the four steam generators; (2) Loss of both main feedwater pumps; (3) Initiation of the safety injection signal; (4) Loss of station normal auxiliary electric power; (5) ATWS Mitigation System Actuation Circuitry (AMSAC) start signal.
o About 15 minutes later, NRC resident questions panel lights o CATC looks at PT steps and logic drawings o About 10 minutes later, DATC determines switches for 2CA15A and 2CA18B not being in "AUT0" could have caused the panel lights o OATC recognizes an abnormal condition und immediately notifies the Control Room SRO
.
o About 5 minutes later, OATC returns switches to " AUTO" o Thorough review of PT and personnel safety had to be conducted
!
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L OATC ACTIONS WITHOUT l
NRC ASSISTANCE f
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The turbine driven pump will automatically start and provide the
Time (Min)
]
i
minimum required feedwater flow within one minute following either of
 
~
o OATC places switches to "CLOSE"
y the following conditions:
:
j i
 
5 o DATC recognizes lights are lit s
!
5-45 o CATC needs STA assistance
!
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- STA not in Control Room i
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(1) Two out of four low-low level alarms in any two of the four steam generators; (2) Loss of station normal auxiliary electric power.
For a transient or accident condition, the minimum CA flow aust be
!
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delivered within one minute of any actuation signal to start the CA pumps.
.
o 0ATC places higher priority on other ongoing l
,
'
activities j
- acknowledging some annunciators
)
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- clam flush PT i
I
- stroking CA pump turbine steam valves for I&E
;
- receiving phone calls concerning CA clam flush i
activities


The minimum flow is considered to be the flow delivered only
;
- - - - - _
mJ 45 0 OATC gets assistance from STA
- priority activities are decreasing
{
45 - 60 o After review of logic drawings and ongoing CA
;
activities, switches are placed in "AUT0"
,
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NOTE: At shift turnover (as1900) all annunciators and 1.47 Panel lights are analyzed by oncoming shift.


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4 WEAKNES8ES IL)ENTIFIED AND j
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CORRECTIVE ACTIONS TAKEN l
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Procedure
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Weaknesses
'
o Fairly new procedure. Only perfomed once per month per unit
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' o' Step-stated " Ensure" instead of " Verify"
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' o'Did not caution operator to significance of "AUT0" position f
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-
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t Corrective ~ Actions l
.
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o Procedure step was changed to' " Verify" t
i o caution was added to proce, dure
' '
o Review of. control board switches and other procedures was conducted i,
.
,
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to steam generators effective in cooldown and does not include flow delivered to a steam generator involved in a feedline to CA line i
l-
break.
.
*
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Accidents analyzed for in Chapter 15 of the Final Safety Analysis Report (FSAR) typically assume a minimum CA flow of 491 gallons per minute (gpm) delivered to two intact steam generators with no operator action for 30 minutes.
J
>
.


For the postulated non-seismic event of loss of all offsite and all onsite emergency A.C. electrical power, the CA System will perform its safety related function. This assessment includes the limitation that no single failure that would prevent the single A.C. power independent turbine driven pump subsystem from functioning occurs during this limiting event.
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The turbine driven pump (CAPT) consists of a direct coupled, single j
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stage Terry turbine rated at 3600 revolutions per minute (RPM) with a l
.
Bingham horizontal seven stage centrifugal pump.


The speed of the turbine is determined by the position of a steam governor valve which is controlled by a Woodward governor.
i i


The. governor is of the mechanical hydraulic type, driven by the turbine rotor through spiral reduction gears.
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The centrifugal force on a set of flyweights moves a spring loaded servo piston rod which. controls the flow of hydraulic fluid to the power cylinder assembly (remote servo) which provides linear motion as the output of the governor.
~~


The work capacity of the remote servo is 29 foot pounds.
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WEAKNESSES IDENTIFIED AND
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CORRECTIVE ACTIONS TAKEN l
Operator Weaknesses
'
o Concern over lake water contamination of CA blocked the thought process on the " AUTO" position r
o OATC did not immediately recognize these lights as " abnormal" and as a
<
,
result did not take immediate action to notify the Control Room SRO or to
','
determine cause of the lights o OATC stated STA involvement would have occurred within a short,
F period of time (within one hour)


A connecting rod transmits linear motion between the power cylinder assembly and a slotted cam crank.
Corrective Actions o operator was individually counseled t
e Purpose and importance of "AUTC" position of these switches o Prompt assistance must be attained for unexpected 1.47 Panel lights o Immediate notification of the Control Room SRO must be made for all abnormal alarms and indications
'
!
c Prior to performing a step, a full understanding of taking the
!
specified action must be attained L
o Operator update was distributed
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o Incident to be thoroughly covered in requal during let segment of next
-
t year j
o More emphasis will be placed on the 1.47 Panel during classroom and l
simulator training in the future


A cam roller is connected to the end of the governor valve stem and is inserted through a bushing into the slot.
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The slot is angled such that vertical motion of the connecting rod and cam crank is transmitted as horizontal motion to l
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the governor valve stem.
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WEAKNESSES IDENTIFIED AND
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i 1.47 Bypass Panel
,
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i Weakn'ess
o Audibl'e alarm f eature was' not' functional
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o Reliability '
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Lo Not user friendly
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Corrective Action I
o Wrote' work requests to get audible alarm functional
o significant improv.iments in reliability has occurred over the last j
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year
,
o Will pursue improvements that will make it easier and faster for the OATC to determine cause of lights
.
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~ The turbine is protected from overspeed by one electrical and one mechanical overspeed sensing device. The mechanical overspeed device setpoint is 125% (4500 RPM).
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Centrifugal force of the rotating turbine shaft causes displacement of the pin type trip weight outward from the shaft axis.
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The pin strikes a ball tappet, lifting it upwards overcoming tappet reset spring force. This releases a spring loaded head lever and connecting rod which causes the turbine trip and throttle valve to close. The device must be reset locally at the turbine.
-


l The electrical overspeed device setpoint is approximately 4100 RPM l
;
and consists of a photoelectric tachometer which operates a solenoid
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l on the trip and throttle valve to close it via a separate mechanism.
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The electrical overspeed device can be reset from the control room.
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_ _ _ _ _ - _ _ _ _ _ _ _ _ - _ _ _ _ _ _ -


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ANNUNCIATORS VERSUS 1.47 PANEL LIGHTS
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1.47 Panel Lights Annunciators o cause is not clear o cause' is clear o No audible alarm o Audible alarm
,
o Not reliablw in past o Reliable'
o Trained to respond quickly o Not emphasized in training o Behind CATC o Face OATC o.Small, hard to read o Large, easy to read
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CA OPERATION WHILE
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y SWITCHES WERE'" CLOSED" i
o' All' normal' CA suction supplies were available and aligned to the CA pumps
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u-o' AnnJnciator response ' for-" Loss of' Normal CA Suction" directs operator to
'"
ensure these valve have opened
;
t i o Emergency procedures direct operator on how to ensure a suction source is maintained as normal suction sources are depleted i
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i o Turbine driven pump would have been realigned for service within a two hour period of time after the governor valve was reinstalled
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.
.
E o CA Pung Turbine is protected from a loss of suction event due to the PT i-alignment
!


Event Description On July 31, 1989, Catawba Unit 2 was operating at 98% power.
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At 1:10 p.m. operations personnel were attempting to perform a routine surveillance test on the turbine driven auxiliary feedwater pump (CAPT). On the first two attempts to start the pump, it oversped and tripped mechanically.
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A Maintenance Engineering Services engineer (NES) was requested to assist in determining the nature of the overspeed problem. At 1:20 p.m. another start attempt was made which also resulted in the pump tripping on mechanical overspeed.
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The engineer observed during the third attempt that the governor valve control linkage did not move to control turbine speed as designed.
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The engineer " exercised" the linkage using a screwdriver and another pump start was attempted.
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ISSUES
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#1 - Safety significance of having three CA pumps inoperable will be
,
it discussed by.Greg;Swindlehurst
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#2 - RN'to CA piping flush procedure,was inadequate'
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The pump performed acceptably during this attempt, was declared operable and returned to service.
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It was subsequently learned that the work performed on the CAPT had been performed without' permission, with no work. request or procedure, in violation of the licensee's Maintenance Program.
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The residents became aware of the event on August 1, during the morning status meeting. Discussions with licensee management at that time revealed that they did not have enough information to discuss the issue in detail, that the (MES) group had been working on the issue, and that any specifics relative to the event would have to come from the aforementioned MES engineer.
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' ISSUES
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#3 - Apparent lack of understanding of system design on the part of the
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DATC.


The MES Supervisor was requested at that time to have the engineer contact the residents.
,
o OATC had a good understanding of system design
'
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O OATC's concern over lake water contamination of CA caused a memory block of " Auto" function
.
,
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,
o Procedure weakness was the primary reason for the mispositioning
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of the switches
.
I'
o Individual was thoroughly counseled s'
.
o Update issued and roqual training for all operators
,
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#4 - OATC did not immediately notify the co-workers or the Control Room
'
SRO and did not take Lumediate action to return the CA pumps to
#
service when the 1,47 Pansl lights were noticed o OATC did not immediately recognize the lights as " Abnormal"
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!i o Usually need assistance to determine reasons for the lights
;
o When reason for lights was discovered, the Control Room SPO was notified and the switches were repositioned to Auto o operator priority of panel lights was not high enough i
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The system engineer called the residents the next day, August 2.
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_ -... -,. _ _ __ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _


During the conversation, it was learned that:
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The system engineer determined during conversations earlier that day with a representative of the company which manufactured the turbine, that the lutricant being used on the control linkage, N5000, was not recommended for that application.


The event appeared to have been caused by the use of improper l
-
lubricant on the governor / control valve linkage.
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SAFETY' SIGNIFICANCE
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i Although the lubricant problem was germane to both units, there had been no action to verify that the unit 1 CAPT was still operable.
1
*
,
EVALUATION OF A FAILURE OF.THE TRANSFER.


The lubricant was to be changed out on both units beginning on or about August 10.
!
* Other than exercising the linkage on the Unit 2 CAPT no corrective action had been performed.
'
-


j The residents voiced their concerns, at that time, relative to the operability of both units' CAPTs.
TO THE ASSURED SUCTION SUPPLY FOR THE-
-
AUXILIARY FEEDWATER SYSTEM
'
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e BACKGROUND AND SCENARIO
.
e PROBIBILITY l


These concerns were based on the fact that the apparent root cause of the problem had apparently been identified.
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s CONCLUSIONS
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The problem had resulted in the inoperability of the Unit 2 CAPT, yet the licensee had not implemented immediate
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BACKGROUND AND SCENARIO
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THE. PURPOSE OF THE NUCLEAR SERVICE WATER CONNECTION TO THE AUXILIARY FEEDWATER PUMP SUCTION IS TO PROVIDE AN
!
ASSURED SUCTION SUPPLY FOLLOWING A SEISMIC EVENT i
!
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)
e A SEISMIC EVENT CAN RESULT IN:
corrective actions to ensure that both units' CAPT's remained operable unt.il the lubricant could be changed, j
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i On the following afternoon, representatives of the licensee's staff, i
:
including the MES engineer, met with the residents to discuss the residents' concerns. During that meeting, it was confirmed that:
' LOSS OF NORMAL AFW SUCTION SOURCES
-
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STATION BLACK 0UT
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e THIS SCENARIO IS WITHIN THE DESIGN BASIS
,
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L e: A FAILURE OF THE AUT0-TRANSFER TO THE ASSURED SUCTION r
SUPPLY RENDERS THE AFW SYSTEM INCAPABLE OF MEETING THE
:
DESIGN BASIS
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The apparent root cause of the problem was the use of the N5000
.
.
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lubricant.
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The licensee had, by August 3, performed a visual examination of j
i
the linkage on the unit 1 CAPT, but had not checked the linkage i
* :
for frcedom of movement nor otherwise verified its operability.
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The schedule for the lubricant replacement had been moved from August 10 to on or about August 6.
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PROBABILITY
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THE SAFE. SHUTDOWN EARTHQUAKE IS 0.15G


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e THE NORMAL AFW SUCTION SUPPLY CAN WITHSTAND A
,
0.3G EARTHQUAKE FROM A REALISTIC. PERSPECTIVE
'
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e THE PROBABILITY OF AN EARTHQUAKE STRONGER THAN
,
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0.3G IS asl X 10-4/YR
;
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e THE INADVERTENT VALVE ALIGNMENT EXISTED FOR
'
35 MINUTES e
THE PROBABILITY OF THE EARTHQUAKE OCCURRING AND
<1 LOSS OF AFW SUCTION IS
'
f-s 1 X 10~4 X
1 HR EE 1 X 10-8


No additional corrective actions or testing had been performed on the unit 2 CAPT.
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The residents reiterated their concern over the operability of the CAPT's, in that the problem had not been resolveo, yet no immediate corrective actions or evaluation had been performed.
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CONCLUSIONS


The residents
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e NORMAL AFW SUCTION SUPPLY WAS AVAlLABLE THROUGHOUT THE
[
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'
also asked if the licensee had planned to perform pre-maintenance tests on the CAPT's.


The licensee informed the residents they had
INCIDENT t
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i not but indicated that they would consider them.
e THE TRANSFER OF SUCTION T0 THE NUCLEAR SERVICE WATER L
SYSTEM IS ONLY REQUIRED FOLLOWING A MAJOR EARTHQUAKE
;
:
e.THE PROBABILITY OF A MAJOR EARTHQUAKE OCCURRING L
COINCIDENT WITH THE VALVE MISALIGNMENT IS NEGLIGIBLE I


These tests would verify the operability of the CAPT's from the time of the identification of the problem until the corrective maintenance was complete.
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IF THE SCENARIO 0F CONCERN OCCURRED, CORE COOLING COULD BE MAINTAINED VIA FEED AND BLEED (EP-2C1)
:
L e
DUE TO THE EXTREMELY LOW PROBABILITY OF THIS SCENARIO, l
AND THE AVAILABILITY OF A BACKUP CORE COOLING METHOD,
-
THIS INCIDENT IS NOT SAFETY SIGNIFICANT
'
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.~.--------- ----------------!
.
--


l On August 5 at 8:42 p.m. the Unit 1 CAPT was run successfully.for a pre-maintenance verification.
.. _.


The governor valve linkage was disassembled, cleaned, lubricated with Neolube 2, and reassembled.
.
..._.


The turbine was retested and returned to service at 12:45 a.m. on j
-
August 7.
. _ _. _. -...
_.


On August 7 at 9:50 a.m. a pre-maintenance verification test was attempted on the Unit 2 CAPT.
_ _
_
i


The turbine oversped and tripped on electrical overspeed.
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ENCLOSURE 4 i
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It was observed that the control linkage moved too sluggishly to control turbine speed properly. At 10:07 a.m. the CAPT was restarted at which time it ran successfully.
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The governor valve linkage was then disassembled, some parts replaced and lubricated with Neolube 2.
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AGENDA g.; g.


It was also found that the governor valve stem had suffered corrosion attack in the area of the stem packing.
NRC ENPORCBMENT CONFERENCE f
UNIT 2 AUXILIARY PEEDWATER PUMP TURBINE (CAPT) OVERSPEED TRIP i
[
*
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- r
- DUKE POWER COMPANY
;
CATAWEA NUCLEAR. STATION
''
OCTOBER.I1. I989
,
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OPENING REMARES T.E.OWEN STATION MANAGER * CMS
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PHYRICAL DESCRIPTION OF CAPT W. R. TOMLINSON t
MAINTENANCE ENOR BREVICES
*
SEQUENCE OF, EVENTS R. A. JdNES (
.. PART HISTORYi PRIOR TO JULY 31.'1989 MAINTENANCE ENOR BERVICES MOR
. EVENTS ; JULY' It-AUGUST 7. !989 ROOT CAUSE/IMMEDIATE AND-W..R. McCOI' LUM LONG TERM CORRNCTIVE ACTION 8 surERiNTENbENT OF MAINTENANCE ANALYSIS OF SYSTEM PERFORMANCE G. E. SW!NDLERURST
.
,
DESIGN ENGINEERINO
*


The valve stem was replaced and at 10:30 a.m. on the trorning of August 9, the Unit 2 CAPT was returned to service.
SUMMARY T.E,OWEN
,
a.


CLOSING REMAREB, J. W. HAMPTON MANAGER MUCLEAR REI.ATI' NS O
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Requirements (1) Technical Specification 3.7.1.2 requires in modes 1, 2, and 3 at least three. independent steam generator auxiliary feedwater pumps and associated flow paths shall be OPERABLE with:
Two motor-driven auxiliary feedwater pumps, each capable of
-
-
being powered from separate emergency busses, and One steam turbine-driven auxiliary feedwater pump capable
;
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"
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SA" SYSTEM DESCRIPTION
.
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of being powered from an OPERABLE steam supply system.
i
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"SA", MAIN STEAM TO AUXILIARY EQUIPMENT.


With one auxiliary feedwater pump inoperable, restore the required auxiliary feedwater pumps to ' OPERABLE status within 72 hours or be in at least HOT STANDBY within-the next 6 hours and in H0T SHUTDOWN within the following 6 hours.
!
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l


With two auxiliary feedwater pumps inoperable, be in at least HOT STANDBY within'6 hours and in HOT SHUTDOWN within-the.following 6 hours.
*
.- AUX. FEEDWATER TURBINE ASSURES AUX. FEEDWATER AVAILABILITY
;
^
:


(2) The Administrative Policy Manual for Nuclear Stations, section 3.3.2.3 requires that maintenance be performed under the control of the Work Request System in accordance with written procedures which conform to applicable codes, standards, specifications and criteria.
- STEAM TO OPERATE THE TURBINE IS DRAWN FROM TWO (2) MAIN STEA
:


Section 3.3.2.5 requires that in the event of an equipment failure, the cause shall be evaluated and equipment of the same type shall be evaluated as to whether or not it can be expected to continue to function in an appropriate manner.
FOR REDUNDANCY
;
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- UPON SIGNAL TO START, SA2 AND SAS OPEN TO PROVIDE STEAM
'
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- SUPPLY LINES ARE HEAT TRACED TO PREVENT CONDENSATION
,
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- AFTER 'STARTUP, CONDENSATE IS REMOVED BY AN ORIFICED DRAIN'NEAR TH TURBINE
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Station Directive 3.3.7, Work Request Preparation, states that the Work Request is the basic document of the Maintenance.
.
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COMPONENTS OF THE SYSTEM
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- SA2 AND SAS ARE AIR OPERATED, BORG-WARNER, 4' GATE VALVES.


Management Program for corrective and preventive maintenance and that employees requesting maintenance assistance are required to comply with the provisions of the program.
f
.
- TRIP AND THROTTLE VALVE IS A
GIMPEL, 4'
GLOBE VALVE WITH A
.,
LIMITORQUE OPERATOR, NORMALLY OPEN.


Maintenance Management Procedure 1.0 further defines Work Request requirements including authorization and definition of work to be performed, documentation of clearance to begin work, procedures to be used, description of maintenance activities performed and documentation of retest activities and acceptance by operations.
,.
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- CONTROL VALVE IS A TERRY CORP./ DRESSER-RAND, 3' CONTROL VALVE AND IS CONTROLLED BY A PG-PL (MECHANICAL / HYDRAULIC) WOO
..
--THE TURBINE IS A TERRY CORP / DRESSER-RAND, GS-2N WITH 1160 BHP.


ELECT. TRIP IS 4140 RPM
'
'
MECH. TRIP IS 4500 RPM
- GOVERNOR CONTROLS - CONTROLS ARE LOCATED IN THE CON
:
!
!
(3)
THE LOCAL PANEL.
ation Directive 3.2.2, Development and' Conduct of the Periodic
 
.est Program, section 6.0 requires that if, for any reason, a surveillance test fails to meet acceptance criteria, the Compliance Engineer and the Shift Supervisor or his designee shall be notified immediately and the equipment - declared inoperable in accordance with the Technical Specification limiting' condition for operation.
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The Shift Supervisor shall
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y OPERATION
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ensure that the proper - course. of action for returning the equipment to operable status is pursued.
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; SA2 AND SAS RECEIVE SIGNAL T0 OPEN.
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'WITHIN'4 TO 5 SEC. STEAM REACHES THE TURBINE.
 
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i Station Directive 3.1.14, Operability Determination, states that when responsible station personnel believe a component is
'uT - AFTER APPR0X.1.5 SEC. GOVERNOR STARTS TO CONTROL THE TURDINE.-
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I operable but have concerns related to it, necessary actions shall be taken expeditiously to resolve the concerns, identify any root cause, and confirm operability.
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These actions shall include additional testing, engineering evaluations, and
'AFTER APPR0X.:3 SEC.:
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calculations or inspections as appropriate to the circumstances.
'
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The directive further requires an " Operability Evaluation Form" i
!
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to be completed to document the concern, the basis for the evaluation and any alternate methods or compensatory measures
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needed to fulfill the component's safety function.
' FAST START RAMPS UP
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* SLOW START DECREASING SPEED.


J Contrary to the above, Administrative Policies a'nd Station Directives the steam turbine auxiliary feedwater pump was i
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returned to service on July 31, 1989, without adequate
.
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;
corrective actions being performed to assure the pump was in i
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fact operable, e.


Safety Significance Issue 1 On July 31, the Unit 2 CAPT tripped on mechanical overspeed on an attempted start.
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- -1AFTER APPROX. 6'SEC.:
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* FAST' START STILL RAMPING UP i
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* SLOW-START REACHING MINIMUM SPEED.


An immediate attempt at a second start was
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also unsuccessful.
:AFTER APPR0X. 32 SEC.:
 
-
A third start attempt was made with an MES l
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Engineer, an Operations Engineer, and a Maintenance Planner observing the activity.
,
* FAST START REACHING FULL SPEED.


Again, the pump tripped on mechanical overspeed and it was observed that the control valve linkage did
.
not move.
The CAPT control valve linkage was then manually I
exercised. The CAPT was started, the linkage responded to control turbine speed, and successfully met the requirements of
,
,
the monthly surveillance test.
* SLOW START STABILIZING AT 1250 RPM.


Based on having passed the surveillance test, the CAPT was declared operable and returned to service.
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- ALL OF CATAWBA NUCLEAR's TRIPS HAVE OCCURRED IN THE FIRST 1.5 SEC.


It was subsequently determined that a work request i
;
was not initiated when the turbine trip occurred, and was not used in investigating the problem.
0F TURBINE ROLL.


The safety significance of this issue concerns the " corrective maintenance" performed by the MES Engineer when he exercised the.
THE FIRST 3 SEC. OF A FAST OR SLOW START ARE THE c
SAME.


control valve linkage.
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Not only war it inappropriate to simply dislodge the stuck linkage but the failure to initiate a work request circumvented the normal process of evaluating equipment operability.
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It is expected that problem resolution be performed under the appropriate programs to ensure that underlying problems are identified and resolved and that an operationally reliable component is returned to service. ' Given the circumstances of this event it is not clear that the CAPT was fully operable when returned to service on July 31, 1989.
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Issue 2 The CAPT oversped at 1:11 p.m.
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on-July 31, passed its surveillance test at 1:25 p.m. that afternoon and then oversped again at 10:00 a.m. -on August 7.
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The surveillance. test performed is termed a " slow start" as the turbine is started with the speed control potentiometer set at minimum' speed, then slowly increased to maximum speed by the operator.
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The safety significance of this issue concerns the fact that normally with the CAPT in standby, a safety _ signal will cause.it to " fast start", or immediately ramp up to operating speed in approximately 30 seconds.
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The inspectors were concerned with the adequacy of the surveillance to demonstrate the ability of the CAPT. to perform its intended safety-function in that a fast
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start was not performed and-the governor: linkage-was exercised prior to performing the -test.


Discussions with the responsible licensee engineer indicated that in this particular event, it would-not have mattered whether a slow or fast start was conducted due to the fact that the failure mechanism of. stem corrosion prevented the governor valve.from closing.
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Slow-starts, however, may not be appropriate for operability testing, as governor problems could potentially remain undetected.
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Ol25 ORIFICES, i
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Issue 3 On July 31, 1989, the unit 2 CAPT tripped a number of times on mechanical overspeed, was returned to service and tripped on overspeed again on the next start attempt on August 7,'1989.
' ORIFICE "O,o40 o
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On August 1, at 4:50 a.m., the Unit 2 Motor Driven CA Pump 2B was. removed from service to repair an oil leak on the bearing housing drain plugs.
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TURBINE H
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Repairs were completed and the pump was returned to service at 3:00 p.m. the same day.
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On August 2, at 3:00 a.m.,
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Nuclear Service Water (RN). System Train B was removed from service for repairs.
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LINE


With RN Train B inoperable, both Unit 1 and Unit 2 Train B Diesel Generators.
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were inoperable due to RN cooling water not being available.
.
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With the Diesel Generators inoperable, essential' power could not be provided to the Unit 1.or Unit 2 CA B Pumps, which were also considered to be inoperable.
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ORIFICE
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On August 4, at 8:00 p.m..,
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RN repair work was complete and the CA Train B Pumps were returned -
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to operable status.


The safety significance of this issue concerns the inoperability of 'the Unit 2 B Train CA Pump during the time the CAPT was in questionable status. Thus, the potential existed for having two auxiliary feedwater pumps inoperable.
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-PAST HISTORY - PRIOR TO JULY 31, 1989
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GOVERNOR VALVE PROBLEMS THAT-HAVE BEEN SEEN AT' CATAWBA l
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UNIT 1:
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,I 11/84 - REPLACED DAMAGED STEM AND PACKING m
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- 10/87'- REPAIRED PACKING LEAK ON GOVERNOR VALVE
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01/89 - REPLACED PUMP ROTATING ELEMENT-(LER 413/89-007)
Issue 4 On August 1, the MES Engineer met with an MES Engineering Supervisor and the MES Manager to' evaluate the prior situation.


with. the Unit 2 CAPT.
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'V DISCOVERED' GOVERNOR -VALVE LINKAGE BINDING DUE TO
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PACKING LEAK WASHING OFF LINKAGE LUBRICATION
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Operability of the Unit 2 CAPT was discussed.- It was the view of those individuals that the Unit 2-CAPT continued to be _ operable at this time.
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Past problems were reviewed taking into consideration present design, repair
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methods, procedures, and types 'of lubricants used.
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aspects, the lubricant used 'on the control valve linkage was
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considered to be the major cause of the July 31 overspeed. trips.
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This-was confirmed the following. day when a manufacturers f
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representative was contacted and recommended that a dry film lubricant be used on the control valve linkage instead of the paste lubricant presently used.
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The' safety significance of-this ' issue concerns the belief on
'
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August 1, by the MES Engineer, Supervisor and Nanager that the lubricant used on the CAPT control valve linkage on both units was considered to be.the major cause of the July 31 overspeed trips.
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However, on August 2 discussions with the MES Engineer revealed that no action or evaluation had-been performed to verify that the Unit 1 CAPT was still ' operable.
UNIT!2:'-
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2/88. >. BROKEN SNAP. RING CAUSED' GOVERNOR VALVE STEM BINDI!
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Issue 5 On or about August 2, licensee management determined that the work that transpired on the Unit 2 CAPT on July 31, in the
3/89 - PREVENTIVE -MAINTENANCE lhSPECTION OF GOVERNOR VALVE
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PERFORMED'
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exercising of the linkage, had been done outside the control.of
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the work request (WR)/ maintenance program, i
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The safety significance of this issue _ concerns the decision by licensee canagement to not declare the CAPT inoperable, enter the maintenance program and ensure the CAPT operable when it was determined that the work of July 31 was performed in = an I
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uncontrolled manner, i
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Issue 6
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On August 3, RN Train B repairs were still in progress'and both Units' CA Pump B inoperable.
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Inspection of the Unit 1 CAPT was
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SUMMARY OF PAST llISTORY:
'
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- HAD SEEN LIMITED VALVE STEM CORROSION IN THE PAST
,
;
- CORROSION WAS NEVER SEVERE EN0 UGH TO CAUSE ANY OPERATIONAL I
"
PROBLEMS
,
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- IN ADDITION, CORROSION HAD OCCURRED OVER A
FAIRLY LONG
'I
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scheduled for ' August 6,' and the Unit 2 CAPT was scheduled for
PERIOD OF TIME (0NE TO TWO YEARS)
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- HAD NOTICED PACKING LEAK-0FF LINE ISOLATION VALVE TENDING TO
'
CLOG 'UP OVER TIME AND HAD INITIATED ACTION TO REMOVE VALVE
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FROM SYSTEM.
 
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' - NO PAST HISTORY OF DOING SAFETY RELATED WORK AT CATAWBA
 
WITHOUT USING PROPER WORK CONTROL PROCESS (VERIFIED THROUGH SEARCH OF PROBLEM INVESTIGATION REPORTS AND LER's)
 
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_ August 7.
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The licensee felt-it was appropriate to wait and not
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SEQUENCE OF EVENTS y.,
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JULY 31, 1989 TO AUGUST 7, 1989 l MONDAY,' JULY 31ST
- U2 CAPT TRIPS ON MECHANICAL OVER-SPEED
,
- MES STAFF ENGINEER INVOLVEMENT
!
--OPERABILITY DETERMINATION
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- FACTORS T0: CONSIDER
.
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TUESDAY, AUGUST.1ST
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- MES MANAGEMENT REVIEW 0F PROBLEM i
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- PLAN OF ACTION ESTABLISHED TO INVESTIGATE LONG TERM
!
IMPLICATIONS
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- RE-EVALUATION OF PUMP OPERABILITY i
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L take the CAPT out of service immediately since the lubricant was l-not a short term operability concern.
!
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WEDNESDAY,-AUGUST 2ND j
!
- STATION MANAGEMENT REVIEW 0F PROBLEM
.
- DISCUSSIONS WITH VEND 0R i
,
- LUBRICATION ISSUE
!
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- PLAN OF ACTION CONCERNING LINKAGE LUBRICATION
- UNIT 1.CAPT VISUAL INSPECTION PERFORMED
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' THURSDAY, AUGUST 3RD
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- ESTABLISHED SCHEDULE FOR PREVENTIVE CLEANING / DISASSEMBLY OF
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UNITS 1 s 2 CAPT GOVERNOR VALVE LINKAGES
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. FRIDAY, AUGUST.4TH i
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- MEETING WITH-STATION GROUPS TO OUTLINE WEEKEND WORK SEQUENCE L
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- MEETING WITH NRC AND MAINTENANCE MANAGEMENT i
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' SATURDAY, AUGUST STH
;
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_ _ - _ _ _ _ _ _ _ _ - _ _ _ _ _ _ _ _ _ - _ _
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- SUCCESSFUL PRE-MAINTENANCE START ON UNIT 1 CAPT
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f SUNDAY, AU6UST 6TH n


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=- UNIT 1~ CAPT. LINKAGE CLEANED, RELUBRICATED, AND SUCCESSFULLY RETESTED'
:
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MONDAY, AUGUST 7TH o
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- UNIT
CAPT TRIPS ON ELECTRICAL OVERSPEED DURING t
' PRE-MAINTENANCE START, SECOND START ATTEMPI IS SUCCESSFUL
'
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- BEGAN GOVERNOR LINKAGE DISASSEMBLY
- DISCOVERED VALVE STEM CORROSION PROBLEM i
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TUESDAY, AUGUST 8TH
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COMPLETED REASSEMBLY OF GOVERNOR VALVE
!
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REMOVED INTERNALS FROM PACKING LEAK-0FF LINE lSOLATION VALVE
-
- TO'' AID ~IN DRAINING OF MOISTURE i
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POST MAINTENANCE RETEST WAS SUCCESSFUL
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10 The safety significance of this issue concerns the' observation that the licensee may have been influenced by the inoperability of the B trains of CA on both units to the point that they were reluctant to take immediate corrective actions to ensure that the CAPT's-remained operable.
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Issue 7 On - August 7, at 9:50' a.m., with Unit 2 in Mode 1, the Unit 2 CAPT tripped on electrical overspeed.
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During this start attempt, the aforementioned MES Engineer observed that the.
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control valve linkage responded to the turbine start, but binding. slowed the response causing the electrical overspeed trip.
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PROBLEM AREA:
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The electrical overspeed trip was reset and..- at 1000 hours, and a second start of the Unit 2 CAPT was successful.
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After securing the pump, linkage disassembly began and the control valve stem was observed to have excessive-drag in the valve assembly.
'
FAILURE TO USE WdRK REQUEST PROCESS TO


Work was expanded to include rebuilding the control valve.
'
TCONTROL. WORK ON JULY 31, 1989.


It was.at this time that it was identified that indeed the event
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ROOT CAUSE:
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of July 31 may have been caused by binding of this valve due to corrosion rather than the linkage / lubricant problem.
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- MES STAFF ENGINEER FAILED TO INITIATE i
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WORK REQUEST PRIOR TO EXERCISING LINKAGE.


The safety significance of this issue concerns the operability of the Unit 2 CAPT during the period of July 31 through August 9,1989.
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In as much as no corrective maintenance was performed on July 31 and the CAPT failed to operate properly on August 7, it raises the concern about the pump's operability due to no corrective action 'being accomplished prior to returning it to service. During this_ period, the Unit 2 B train
;
;
motor driven CA pump was also inoperable from 4:50 a.m. until 3:00 p.m. on August 1 and -from 3:00 a.m. on August 2 until 8:17 p.m. on August 4.
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Conclusions (1) On July 31, the Unit 2 CAPT tripped several times on mechanical overspeed, no corrective ' maintenance was performed and the l
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l component was returned to service, (2) On July 31, when'the Unit 2 CAPT malfunctioned, an MES engineer exercised the governor valve linkage. i.e. performed work on a safety related component without permissinn, with no procedure, in violation of the Maintenance Program.
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l (3) On or about August 2, licensee management determined that the work which had been performed on the Unit 2 CAPT on July 31 had been uncontrolled, yet no actions were taken to enter the maintenance program and ensure that the CAPT was operabl i
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in CORRECTIVE ACTIONS:
.
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11.
'MES STAFF ENGINEER COUNSELLED.


(4) In as much as no corrective maintenance was performed on the l
' STATION MANAGER STAFF NOTES DISCUSSED
Unit 2 CAPT on or after July 31 and in as much as the component oversped again on August 7, during the next attempt to start the component, it raises concern about the pump's operability.
.c THROUGHOUT ORGANIZATION:
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' EMPHASIZED NEED TO FIND ROOT CAUSES.


(5) The Unit 2 B train motor driven CA prmp was inoperable simultaneously with the CAPT, on August 1 from 4:50 a.m. until 3:00 p.m. and from 3:00 a.m. on August 2 until 8:00 p.m. on August 4.
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'NEED TO USE PROPER PROCESSES.
:
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'MES SECTION MANAGER MET WITH SECTION l
MEMBERS:
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+ DISCUSSED NEED TO USE APPROPRIATE WORK i
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CONTROL PROCESS.
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+ DISCUSSED NEED TO BE SENSITIVE TO i
FINDING REAL ROOT CAUSE.


3.
<
.-
,
+ REINFORCED NEED TO INVOLVE ENGINEERING i
SUPERVISORS IN SAFETY-RELATED OPERABILITY
;
DECISIONS.


Auxiliary Feedwater Suction Valve Event a.
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Executive Summacy On September 12, 1989, the Resident Inspector discovered that Unit 2
0
;
,
control board switches for ' valves which automatically align the l
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suction of both Unit 2 motor driven auxiliary feedwater pumps to the
-
!
-
system's only safety related, assured suction source, had been
-'vv-*'---
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mispositioned such that automatic realignment on a low suction pressure would not occur.
*- - = ' - - * - *~
~ -- - -- - * ~
- -'------
- - - - - - -
- - - - -


It was determined that the switches had been mispositioned some 30 minutes prior to discovery during the i
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performance of a piping flush procedure.


During this time, the i
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j turbine driven auxiliary feedwater pump was also inoperable for maintenance.
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The mispositioned switches were immediately identified to the Shift Supervisor, and they were placed to the AUTO position l
- PROBLEM AREA:
which in turn returned the motor driven auxiliary feedwater pumps to operable status, b.
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,
. BINDING OF GOVERNOR VALVE z
,
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Event Description On September 12, 1989, during a routine control room tour, the Resident Inspector detected that the Unit 2 Control Room System Bypass Panel (installed in accordance with Regulatory Guide 1.47)
.;
ROOT CAUSE:
.
;
;
indicated that all three Auxiliary Feedwater (CA) pumps were
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CORROSION.OF NITRITED' LAYER OF 410-STAINLESS STEEL-VALVE STEM.


inoperable.
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The system is comprised of.a turbine driven pump (CAPT)-
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and two motor driven pumps.


It was also determined that the CAPT was inoperable due to ongoing maintenance.
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The inspectar questioned the Unit 2 Operator at the Controls (0ATC) as to why br/d motor driven CA pumps indicated inoperable.
.
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IMMEDIATE i
CORRECTIVE ACTIONS:
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'NEW GOVERNOR VALVE STEM WAS INSTALLED.


The 0ATC was aware of the indications and considered the cause to be associated with valve manipulations performed to facilitate the ongoing flush of the Nuclear Service i
ON UNIT 2.
Water (RN) to CA snction lines. The operator was not sure, however, which component realignments were causing the bypass panel indi-cations.


At the inspectors request, the 0ATC reviewed applicable
'
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' MOISTURE DRAIN PATH WAS IMPROVED BY IMMEDIATELY REMOVING DRAIN LINE VALVE
,
,
logic diagrams and determined that the motor driven CA pump flow
l
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INTERNALS, THEN SUBSEQUENTLY MODIFYING DRAIN LINES TO DELETE VALVES.
 
'
'
paths were inoperable due to the. control board switches for valves 2CA-15 and 2CA-18, the CA pump 2A and 2B suction isolation valves from RN, being in the "CLOSE" position.


These switches have three positions: OPEN, AUT0, and CLOSE.
1
' COMPENSATORY ACTION TO PERFORM LINKAGE
[
AND PACKING DRAG TEST AND START TEST Y
OF PUMP ON 2 WEEK INTERVAL WAS PUT INTO
.
.
PLACE.


The valves are normally closed
,
_ _ _ _ _ _ _ _ _
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i with their switches in AUTO.
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The safety' related function of these valves is to open automatically upon a low CA suction pressure in order to supply RN to the CA system.
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The four normal condensate-grade suction sources for CA are neither safety related nor seismic.
,
- PERFORM MODIFICATIONS TO INCREASE RELIABILIT:
'
0F DRAINAGE FLOW PATHS.


RN is the only safety related assured suction source.to CA.
z t
.
-
- PERFORMED ON BOTH UNITS
"
- REORIENTED-LEAK-OFF LINE
!
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- DELETED' LEAK-OFF LINE ISOLATION VALVE
.
:
,
.
MODIFIED STEAM SUPPLY VALVE STROKE TIME
,
:
- SLOWED DOWN VALVE STROKE TIME L
I
- ALLOWS SLOWER RATE OF STEAM ADMISSION
;
;
TO TURBINE
- EASIER FOR GOVERNOR TO CONTROL
:
3-i i
l


The inspector immediately informed thel Shift Supervisor of the identi--
.
fication that both motor driven CA pumps were inoperable'due to the inability to automatica11y' swap to RN on a low suction pressure I
' ''
condition.- The Shift Supervisor concurred and had the 0ATC place the-switches for 2CA-15 and 2CA-18 in the AUTO position at approximately
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2:10 p.m., some 35 minutes after the switches had been misa11gned.
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I At this point the System Bypass Panel lights for Train A and Train B CA went out indicating that both trains had been returned to service.
n,-,,.
- - -. -...
.,,, -...... - - - - -, -..... - - _ - -- - - - - - - - - - _ _ - - - -- --


The inspuctor reviewed the ongoing flush procedure, PT/2/A/4200/59, RN to CA Piping Flush.
,
-
.
.
.
..
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Step 12.2.6 of that procedure requires the operator to " Ensure the following valve are closed: 2CA-15 and
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FOLLOW-UP ACTIONS:
.
'
.
PERFORM PACKING. DRAG TESTS EVERY TWO e
WEEKS AND TREND RESULTS.


2CA-18." At 1:35 p.m., upon performing this step, the 0ATC ensured the valves were closed by observing the control board indicating lights.
- SUCCESSFUL LINKAGE / PACKING-DRAG TEST-i
'
PERFORMED ON BOTH UNITS l
,
>
'
. - 3 ON UNIT 1 l'l
- 2 ON UNIT 2


However, she also incorrectly decided to assure the valves would not inadvertently oper by taking the aforementioned switches from AUTO to CLOSE.
- TESTS HAVE SHOWN NO INCREASE IN DRAG'
FORCE f
GOVERNOR VALVE STEM INSPECTIONS u
- INSPECTED VALVE. STEMS ON BOTH UNITS
.
- MINIMAL CORROSION ON UNIT 1 STEM (HAD BEEN IN SERVICE FOR 2 YEARS)
- NEGLIGIBLE CORROSION ON UNIT 2 STEM
'
(DISCOLORATION)
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This would have prevented the automatic opening-of these valves in the event of a low suction pressure condition.
- -
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.
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i
'3-LONG - TERM ACTIONS:
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' INITIATED AUX FEED PUMP WORKING GROUP k
TO DEVELOP LONG TERM ACTION PLAN TO ENHA RELIABILITY:
(SIMILAR TO D/G EFFORTS)
!
A.
 
LINKAGE AND GOVERNOR CONTROL
\\
'
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,
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-
B.
 
GOVERNOR VALVE i,
!
STEAM SUP;)LY AND DRAINAGE PATHS.
 
!
c.


It should be noted that this step was also independently verified by a-non-licensed operator.
I D.


Further review of the procedure revealed that both 2CA-15 and 2CA-18 are cycled open and closed after the flush.
MATERIALS AND COMPONENT CONCERNS.


The switches are then placed in AUTO.
E.


These steps were performed.at or about 12:26 a.m.
PROCEDURES F.


the next morning, September 13.
TRAINING t
i
!
INCREASED ATTENTION TO TIMING OF G.


Based solely-on the time that this particular procedure step was performed, the potential existed to have all three CA pumps inoperable for a period of approximately 11
!
!
aux. FEED PUMP STARTUP AFTER PACKING DRAG TEST.


hours, had the error gone undetected.
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It should be noted, however.
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l that it is quite probable that this error would have been detected -
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during shift turnover since the 1.47 panel is specifically referenced in the turnover procedure.
!
SAFETY SIGNIFICANCE l
i l
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i L
ANALYSIS OF THE IMPACT OF A
!
l DEGRADED AUX 1LIARY FEEDWATER SYSTEM L
ON THE LIMITING FSAR TRANSIENT
'
,
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e BACKGROUND
.
e WORST CASE SCENARIO I
!
e ANALYSIS METHODOLOGY
;
.
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RESULTS j
!
e CONCLUSIONS
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BACKGROUND L
i e
FSAR STATES THAT AT LEAST TWO STEAM GENERATORS CAN BE SUPPLIED WITH A MINIMUM 0F 490 GPM OF AUX 1LIARY FEEDWATER e
THE DEGRADED SITUATION RESULTS IN N0 AUXlLIARY FEEDWATER IMMEDIATELY AVAILABLE
- ONE MOTOR-DRIVEN PUMP INOPERABLE i
- ONE MOTOR-DRIVEN PUMP ASSUMED LOST AS THE LIMITING SINGLE FAILURE
,
- THE TURBINE-DRIVEN PUMP TRIPS ON OVERSPEED e
LESS AUXILIARY FEEDWATER FLOW THAN ASSUMED IN THE FSAR CHAPTER 15 TRANSIENT AND ACCIDENT ANALYSES, e
OPERATOR ACTION REQUIRED TO RESTORE ADEQUATE AUXILIARY FEEDWATER FLOW i
 
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WORST CASE SCENARIA
,
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THE LIMITING SCENARIO IS A MAIN FEEDWATER LINE BREAK IN e
EITHER STEAM GENERATOR 'B' OR 'C'
,
l ALL MAIN FEEDWATER LOST AT TIME ZERO
-
ALL FOUR STEAM GENERATORS BLOW DOWN
-
i UNTil MSIV CLOSURE ON LOW STEAM LINE PRESSURE NO AUXlLIARY FEEDWATER IMMEDIATELY
-
AVAILABLE e
OPERATOR ACTIONS
,
ISOLATE AUXILIARY FEEDWATER TO THE
-
FAULTED STEAM GENERATOR (0-600 SECONDS)
RESTART TURBINE-DRIVEN AUX 1LIARY
-
FEEDWATER PbMP (600 SECONDS) -
PROVIDES A MINIMUM FLOW 0F 298 GPM TO ONE STEAM GENERATOR AllGN TURBINE-DRIVEN PUMP TO A SECOND
-
,
STEAM GENERATOR (900 SECONDS) -
PROVIDES A MINIMUM FLOW 0F 554 GPM REC 0VERY ACTIONS INVOLVE THROTTLING
-
AUXILIARY FEEDWATER FLOW AND TERMINATING SAFETY INJECTION
.
i


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-


Requirements Technical Specification 3.7.1.2 requires in Modes 1, 2, and 3 that
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l at least three independent steam generator auxiliary feedwater pumps
,-
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and associated flow paths shall be OPERABLE with:
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,
l, Two motor-driven auxiliary feedwater pumps, each capable of-
!
':
ANALYSIS METHODOLOGY
!
'
'
;
;
being powered from separate emergency busses, and
'
, -
s PLANT-SPECIFIC SIMULATION OF THE WORST CASE SCENARIO USING l
A THREE-LOOP CATAWBA UNIT 1 RETRAN-02 MODEL
!
!
e BOUNDARY CONDITIONS
 
!
!
MAIN FEEDWATER LINE BREAK TO EITHER STEAM l
-
GENERATOR 'B' OR 'C'
l
,
,
One steam turbine-driven auxiliary feedwater pump capable of being powered from an OPERABLE steam supply system.
..
 
'
j With one auxiliary feedwater pump inoperable, restore the required auxiliary feedwater -pumps to OPERABLE status J
NO AUXILIARY FEEDWATER UNTil 600 SECONDS
-
AUX 1LIARY FEEDWATER FLOW FROM 600-900
.
-
SECONDS CORRESPONDING TO FLOW TO ONE STEAM l
GENERATOR AUXILIARY FEEDWATER FLOW FROM 900-2400
-
i SECONDS CORRESPONDING TO FLOW TO TWO STEAM
!
GENERATOR
;
!
REALISTIC HIGH DECAY HEAT I
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within 72 hours or be in at least HOT STANDBY within the next 6 hours and in HOT SHUTDOWN within the following 6 hours.
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With two auxiliary feedwater pumps inoperable, be in at least HOT STANDBY within 6 hours and in HOT SHUTDOWN within the following 6 hours.
...m.-,-..--m-.
-.
- - - -
.
-


With three auxiliary feedwater pumps inoperable, immediately initiate corrective action to restore at least one auxiliary feedwater pump to OPERABLE status as soon as possible.
.
'g.


Contrary to the above, on September 12, 1989, at 1:35 p.m.-with the Unit 2 Turbine Driven Auxiliary Feedwater Pump inoperable, the operator incorrectly selected the control board switches for 2CA-15 and 2CA-18, Auxiliary Feedwater Pumps 2A and 28 Suction Isolation Valves From Nuclear Service Water, to the CLOSE position.
.
...
.
.'
I
' *
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l RESULTS i
,
i SEQUENCE OF EVENTS
!
.
T!ME (SEC)
EVENT
!
O FEEDWATER LINE BREAK
;
2.6 PZR SPRAY ON
:
'14.5 RX TRIP ON LOW-LOW SG LEVEL 14.7 TURBINE TRIP
.l 15.8 PZR SPRAY OFF i
16.7 PZR HEATERS ENERGlZE
'
'
'181 SAFETY INJECTION ON LOW PZR PRESSURE
.
191 NV AND NI PUMPS START t
300 MINIMUM RCS PRESSURE = 1816 PSIG
'392 MAIN STEAM ISOLATION ON LOW SG PRESSURE
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L
'490 SPDS RED ALARM - LOSS OF HEAT SINK l
554 PZR HEATERS OFF i
563 PZR SPRAY ON f
L
'600 TD AUX FDW PUMP STARTED
;
900 TD AUX FDW PUMP ALIGNED TO SECOND SG l
*1490 PZR WATER SOLID


This rendered the 2A and 2B Motor Driven Auxiliary Feedwater Pumps inoperable in that it removed the ability' of 2CA-15 and 2CA-18 to automatically actuate to the full open position within 16 seconds after a loss of suction and provide a flow path from Nuclear Service Water, the assured source of. makeup water.
1496 PZR PORVS BEGIN CYCLING
-
-
1596 MAIN STEAM SAFETY VALVES BEGIN CYCLING l
l 2400 END OF SIMULATION
[


The condition was indicated by illuminated -lights on. the Unit 2 Control Room System Bypass Panel.. Even though the operator was aware that all three auxiliary feedwater pump lights on the Unit 2 Control Room' System Bypass Panel were illuminated, the operator failed to recognize the significance of the indications.
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The operator. therefore, failed to immediately initiate corrective action to restore at least one auxiliary feedwater pump to an operable status until 2:10 p.n..
~
when the inoperability was identified by the NRC inspector.
_
.
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Technical Specification 6.8.1 requires that written procedures be established, implemented, and maintained covering the activities referenced in Appendix A of Regulatory Guide 1.33, Revision 2 February 1978, which includes the operation and testing of safety related equipment.
.
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CNS FWLB WITH TD AUX FDW @ 600 SEC i -


These procedures are to be sufficiently detailed to support the successful completion of the applicable evolution.
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Further, it is required that personnel employ these procedures when performing those evolutions.
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Contrary to the above, PT/2/A/4200/59, Nuclear Service Water-(RN) to Auxiliary Feedwater (CA) Piping Flush, was inadequate in that step 12.2.6 required the operator to " Ensure the following valves are closed: 2CA-15 and 2CA-18".- However, it. failed to assure that the control board switches for the valves remained in the AUTO position.
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STEAM upt i
ISOLATION
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This contributed to the operator incorrectly selecting the switches
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to the CLOSE position on September 12,:1989, on Unit 2 at 1:35-p.m.
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This removed the ability of 2CA-15 and 2CA-18 to automatically actuate to the full open position within 16 seconds after a loss of
,
,
suction, rendering' train A and B of the Auxiliary Feedwater system inoperable.


_ _ _ _ _
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.
Contrary to the above, the 0ATC failed to follow procedures in that the 0ATC:
. D.
(1) was not knowledgeable of the unit status; (2) did not operate the unit in compliance with technical specifications; (3) did not ensure that the " Control Room Supervisor" was notified of the abnormal condition indicated on the R.G. 1.47 panel; (4) did not initiate prompt corrective action to a received alarm; (5) did not notify the " Control Room Supervisor" of the unexpected alarm.


This is required by Operations Management Procedure 1-0, Section 7.2.B.
,
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Operator At the Controls.
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d.
CNS FWLB WITH TD AUX FDW @ 600 SEC
.
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Safety Significance Issue 1 At approximately 1:35 p.m. on September 12, 1989, the Unit 2 0ATC misaligned the switches which control valves 2CA-15 and 2CA-18, the CA suction isolation valves from RN, such that the valves would not have automatically opened on a low suction pressure signal.
'
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-
.


This action rendered both motor driven CA pumps incapable of performing their intended safety function under certain conditions. The turbine
.
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!
driven CA pump was inoperable for maintenance.
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s INTACT SGs WITM
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Thus, for some 35 minutes, all three CA pumps were inoperable.
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l The safety significance of this issue concerns the inoperability of
 
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the CA system, the inability to remove decay heat from the steam generators under certain accident conditions, and the potential for
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the system being inoperable for much longer had the error not been
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identified by the NRC.
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Issue 2 Procedure PT-2-A-4200-59, RN to CA Piping Flush, was inadequate in
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,
,
that step 12.2.6 requires the operator to ensure that valves 2CA-15 i
i V
and 2CA-18 are closed, but does nct caution the operator that placing the switches for these valves in the "CLOSE" position, renders the applicable pumps inoperable.
f
 
The safety significance of this issue concerns the inadequacy of the procedural guidance which allowed the operator to comply with the procedure step yet render both motor driven CA pumps inoperable.
 
Issue 3 i
Although the OATC was aware that the lights on the RG 1.47 bypass panel had illuminated, indicating that both motor driven CA pumps were inoperable, and considered the reason to be associated with the
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..
15-ongoing flush procedure, she did not know that placing the switches for 2CA-15 and 2CA-18 in the "CLOSE" position had made both motor driven CA pumps inoperable.
-
-
,
- -
-


The safety significance of this issue involves the apparent. lack of understanding of system design and operation.on the part of the 0ATC.
-
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. _ - _ - - -
.
.
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Issue 4-During the event, the 0ATC violated Catawba Operations Management Procedure (OMP) 1-8, Section 7.2.B. which delineates, in part, the requirements and responsibilities of the 0ATC in that she did not notify the Control Room Supervisor of the abnormal condition
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indicated on the 1.47 bypass panel.. nor did she initiate prompt-corrective action to the received alarm / indication.
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STEAM U NE 523 ISOLATI0lt
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The safety' significance of this issue concerns the failure of the 0ATC to identify to her co-workers or management an abnormal condition and her failure to take prompt corrective action to return the motor friven CA pumps to service once she had identified on the 1.47 status panel that.they appeared to be inoperable, e.
-.,nn-
 
....-~.,-,,,-.,n
Conclusions (1) At 13:35 p.m. on September 12, 1989, the Catawba Unit 2 0ATC j
,,,-- - -...-_.....,. - --._ -
misaligned valve control switches for valves 2CA-15 and 2CA-18 which rendered both motor driven CA pumps inoperable.
..
-- - - - - - - -
-- - --
-


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-
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.
.
.
.
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.
.
CNS FWLB WITH TD AUX FDW @ 600 SEC
:
-
!
/ 1 i


4 (2) The 0ATC failed to take prompt corrective action to return the CA pumps to operable status once - she noted their apparent inoperability on the 1.47 panel.
'
NATER i
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(3) The 0ATC was apparently not thoroughly knowledgeable with the CA system design or interface.
,
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=
i


/
.
;
;
(4) The 0ATC failed to identify the abnormality she detected on the
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!
1.47 panel to her fellow operator or her operations management.
'
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(5) Procedure FT-2-A-4200-59 was inadequate' in that - the guidance l
-
provided to the operator did not caution her that placing the l
i
switch for valves 2CA-15 and 2CA-18 in' the "CLOSE", position
.
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.
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rendered the motor driven pumps inoperable.
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L 4.
,


Exit Interview l
!
The inspection scope and findings were summarized on August 24, 1989, and i
!
September 15, 1989, with those persons indicated in. paragraph 1.
,


The i
;
inspector described the ' areas' inspected and discussed in detail the inspection findings listed below.. No dissenting comments were received from the licensee.
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-16 the materials. provided 'to or reviewed by the. inspectors during this inspection.
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Findings Apparent Violation involving. inadequate corrective action associated with the return to service of the Unit-2 turbine driven auxiliary feedwater
.
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pump following failure of a surveillance.-
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Apparent violation involving an inadequate procedure which failed to j
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assure that the CA system would automatically realign the suction of both Unit-2 motor-driven CA pumps to the RN system. This rendered both trains of CA inoperable.
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e UNIT STATUS AT 40 MINUTES IS NOT SERIOUSLY DEGRADED
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RCS IS WATER SOLID WITH S1 INJECTING
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AUX FDW FLOW IS BEING SUPPLIED TO TWO
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L STEAM GENERATORS IN EXCESS OF DESIGN l
REQUIREMENTS
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RCS T-AVE IS 570 F AND HAS BEEN STABLE j
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FOR TEN MINUTES
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UNIT REC 0VERY TO ATTAIN NORMAL POST-TRIP CONDITIONS CAN
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e ALTHOUGH THE DESIGN BASIS AUXILIARY FEEDWATER FLOW
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REQUIREMENT WAS NOT MET FOR FIFTEEN MINUTES, THE PLANT TRANSIENT RESPONSE DID NOT APPROACH ANY SAFETY LIMITS
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Revision as of 17:21, 31 December 2024

Forwards Summary of 891012 Enforcement Conference Re Insp Repts 50-413/89-25 & 50-414/89-25 & Unit 2 Turbine Driven Auxiliary Feedwater Pump Overspeed Trip.List of Attendees & Handout Encl
ML19325E154
Person / Time
Site: Catawba  Duke Energy icon.png
Issue date: 10/26/1989
From: Ebneter S
NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION II)
To: Tucker H
DUKE POWER CO.
References
NUDOCS 8911020120
Download: ML19325E154 (53)
v • d • e


Text

{{#Wiki_filter:m. _ gy - .9 e Yb . OCT e 61989 j , fll Docket Nos. 50-413, 50-414 L License Nos. NPF-35, NPF-52 l t i Duke Power Company

' '. ATTN: Mr. H. B. Tucker, Vice President ' Nuclear Production Department

422 South Church Street

Charlotte, NC 28242 i Gentlemen: ! i

l' SUBJECT: ENFORCEMENT CONFERENCE SUMMARY j (NRC INSPECTION REPORT N05, 50-413/89-25 AND 50-414/89-25)

, This letter refers to the Enforcement Conference held at our request on i October 12, 1989.

This meeting concerned activities authorized for your

Catawba facility.

The issues discussed at this conference related to the

Unit 2 turbine driven auxiliary feedwater pump overspeed trip and the ! mispositioning of Unit 2 Auxiliary Feedwater system control board switches and f assured suction supply valve closure.

A list of attendees, a summary, and a i ! copy of your handouts are enclored.

We are continuing our review of these issues to determine the appropriate enforcement action.

l f In accordance with Section 2.790 of the NRC's " Rules of Practice," Part 2, Title 10, Code of Federal Regulations, a copy of this letter and its enclosures [ will be placed in the NRC Public Document Room.

l ' . Should you have any questions concerning this matter, please contact us.

!-;

Sincerely, 'I 06= Et y_A l H>mt^% CAW.Cs & V \\ Stewart D. Ebneter i Regional Administrator Enclosures: i . 1.

List of Attendees ' 2. ' Enforcement Conference Summary

3.

AFW Suction Supply Valve Closure -! Handout i 4.

Turbine Driven AFW Pump Overspeed

Handcut j t cc w/encis:

T. B. Owen, Station Manager

Catawba Nuclear Station l P 0.' Box 256 i Clover, SC 29710 ' (cc w/encls cont'd - see page 2) l , 8911020120 891026 ADOCK03OOg3 DR p j

.. .

., _ - - ,

W ,. , ,

Duke Power Company

i \\1 007 e 6 FM ! cc w/ enc 1st Cont'd ! Peter G. LeRoy Nuclear Production Department , Duke Power Company t ! P. O. Box 33189 Charlotte. hC 20241 l

A. V. Carr. Esq.

l Duke Power Company l 422 South Church Street i Charlotte. NC 28242 { J. Michael McGarry. !!!. Esc.

l Bishop. Cook. Purcell and Reynolds - 1400 L Street. NW i Washington. D. C.

20005 i i North Carolina MPA-1 L 3100 Smoketree Ct.. Suite 600 , P. O. Box 29513 ! Raleigh. NC 27626-0513 Heyward G. Shealy. Chief i ! Bureau of Radiological Health South Carolina Depart:nent of Health , and Environmental Control l 2600 Bull Street l Columbia. SC 29201 ! t Richard P. Wilson. Esq.

Assistant Attorney General

S. C. Attorney General's Office ! P. O. Box 11549 i Columbia. SC 29211 ! i Michael Hirsch Federal Emergency Management Agency ! b .'

f hn o .

North Carolina Electric

Membership Corporation ' 3400 Sumner Boulevard - s i P. O. Box 27306 Raleigh. NC 27611 F i Karen E. Long i Assistant Attorney General . N. C. Department of Justice ! P. O. Box 629 Raleigh. NC 27602 ) (cc w/ enc 1s cont'd - see page 3) ! ! . - . .-. .. .

-- g , ' ' _ ..<j l Duke Power Company

j L oct 2 s ses

} cc w/ enc 15: Cont'd

L Saluda River Electric i Cooperative. Inc.

i P. O. Box 929 ' , i Ladrons. SC 29360

- S. S. Kilborn. Area Mana9er i (< Mid South Area ESSD Projects ) Westinghouse Electric Corporation i MNC West Tower - Bay 239 - I P. O. Box 335

l Pittsburg. PA 15230

<

l County Mana9er of York County l York County Courthouse York. SC 29745 i Piedmont Municipal Power Agency l 100 Memorial Drive Greer. SC 29651 State of South Carolina r bec w/encis: K. N. Jabbour. NRR Document Control Desk NRC Resident Inspector 'U.S. Nuclear Regulatory Commission Route 2. Box 179-N York. SC 29745 Ril:0,RP RI! P RI .P R1 : Rll O P spr .Shymlock AHerdt iJ ns TReyes 10t#/89 10/3(/89 10/jf/89 10/fs789 10/,3-{ /89 i <

-- , -

' .t / - I t ENCLOSURE 1 ' LIST OF ATTENDEES U.S. Nuclear Regulatory Commission j i S. D. Ebneter. Regional Adminit,trator , ' A. Gibson. Acting Deputy Regional Administrator ' E. W. Merschoff. Deputy Director. Division of Reactor Safety (DRS) G. R. Jenkins. Director. Enforcement and Investigation Coordination Staff ' (EICS)

' M. B. Shymlock. Section Chief. Division of Reactor Projects (DRP) ' K. N. Jabbour. Project Manager. Office of Nuclear Reactor Regulation (NRR) I W. T. Orders. Senior Resident Inspector. Catawba. DRP M. S. Lesser. Resident Inspector. Catawba. DRP , B. R. Bonser. Project Engineer. DRP ! B. Uryc. Enforcement Coordinator. ElCS i Duke Power Company ! ! J. W. Hampton General Manager. Nuclear Relations T. D. Owen. Station Manager. Catawba R. Gill. Manager Regulatory Compliance i R. G. Morgan. Regulatory CCTpliance. General Office R. N. Casler. Operations Superintendent. Catawba , R. M. Glover. Compliance Engineer. Catawba ' W. R. McCollum, Maintenance Superintendent. Catawba R. A. Jones. Manager. Maintenance Engineering Services ' t W. R. Tomlinson. Maintenance Engineering Services G. B. Swindlehurst. Design Engineering. General Office

D. M. Cameron. Project Engineer. North Carolina Municipal Power Agency l

, ! ! , 6 o i , ,'

- '

l L ' i FNCLOSURE 2 l ENFORCEMENT CONFERENCE SUMMARY I On October 12. 1989, representatives f rom Duke Power Company (DPC) met with the NRC in the Region !! office in Atlanta. Georgia to discuss two Auxiliary i Feedwater (CA) system issues.

The first issue concerned mispositioning of CA

! system control board valve switches which control the realignment of both ' Unit 2 motor driven CA pump suctions to Nuclear Service Water.

The second ! I issue concerned a Unit 2 turbine driven CA pump overspeed trip and subsequent return to service without adequate corrective action.

Following opening remarks by Stewart Ebneter. NRC Rll Regional Administrator.

' DPC gave a presentation (Enclosures 3 & 4) on the CA issues.

T. B. Owen.

Catawba Station Manager. introduced OPCs presentations. The first presentation ! covered the Unit 2 CA pump inoperability due to mispositioning of the control i board switches and included a secuence of events, weaknesses identified / ! corrective actions taken. safety significance. a suunary and concluding remarks.

The second presentation covered the Unit 2 turbine driven CA pump overspeed trip and included a physical description of the turbine driven pump, a sequence of events, root cause/immediate and long-term corrective actions. an l analysis of system performance, a summary. and closing remarks.

I The NRC closed the meeting by stating that DPC's presentations had served to enhance Region II's understanding of the issues and DPC's corrective actions.

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.. . pa, j , [NCLOSURE 3 ' . i ' I ! a i ! f I ! i ! , AOBNDA ! t NRC RMPORCBMBNT CONFSRBMcB ! UNIT 3 AUwrn.tAaY FREDFUMP IMOpan ARRt.RTY DUE TO CLAM FLUSE AND ASSURSD SUCTION SUFFLY VALVE CLOSURE ! \\

i DUES F0WER COMPANY l CATAWBA NUCLEAR STATION i OCTOSSR I3,!$89 j il l i ! 0FBNING Rau AaEn T.8.OWBN i STATION MANAORR = CNS ! i !

SSQUENCE OF BVBNTS R. N. CASLER - l SUPERINTANDENT OF OPERATIONS !

. I WBARNESSES ADENTIFIED/ R. N. CARLER 'r i conasCTIVs ACTIONS TAERN SUPERINTENDENT OF OPERATIONS f !

SAFSTY SIGNIFICANCE O. B. SWINDLREURST DaSION sNORNaamrNO ! SUuuAmY T.B.OWBN STATION MANAORA = CMS {

CLOS 8HO Rau Aara J. W. MAMPTON MANAORE OF NUCt. EAR amt.4TIONS j t , t l-l l t l [ P .-------_-_.,m_____-m___-______..--._.~.-----_,_...-_.m-.---. ..-,. . ,m-. -. - -, ...mm-s. -. -,--~m, - - - -.. _,,,,. - - -.. -

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D- ) .. NDeunAL ALIGNISEffT l RN-NUCLEAR SERVICE WATER l CA-AUX.FEEDWATER RC-CONDENSER CIRCULATING WATER N X TuRe:Ne DRivEu CA-7A - [ AUX. FEEDWATER (

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1.In. .m n. . ! 3,PMSCD .,PmS$(0 .,Pattt0 .r?mb.tD .,PellCD ,PASMD i . LIGHTED PUSHBUTTON PANEL - 1BP'1 LOC e OPimical OLSK. Isa!N Comi% A00W .

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' lO a l'.' ' i ' t SEQUENCE OF EVENTS f-i O kN to CA Piping Clan Flush PT in progress o CA Pump Turbine steam supply and water suction valves are closed during this PT o 0ATC places 2CA15A and 2CA18B switches to "CLOSE" o About 5 minutes later, DATC notices 1.47 Panel lights for "A" and "B" train - CA lit ' o Having a light is not always an accurate operability indication o Some PT's cause panel lights to come on o 0ATC needed STA assistance to determine reason for lights o STA was not in control room at that time o STA assistance is normally required o CATC was sure lights were caused by the CA activities o 0ATC did not fully understand the lights but did not immediately consider them' abnormal e o About 15 minutes later, NRC resident questions panel lights o CATC looks at PT steps and logic drawings o About 10 minutes later, DATC determines switches for 2CA15A and 2CA18B not being in "AUT0" could have caused the panel lights o OATC recognizes an abnormal condition und immediately notifies the Control Room SRO . o About 5 minutes later, OATC returns switches to " AUTO" o Thorough review of PT and personnel safety had to be conducted ! --

-- -. - - ., e '. . ,. . . L OATC ACTIONS WITHOUT l NRC ASSISTANCE f ' Time (Min) i

o OATC places switches to "CLOSE"

5 o DATC recognizes lights are lit s ! 5-45 o CATC needs STA assistance ! I - STA not in Control Room i ' ! . o 0ATC places higher priority on other ongoing l , ' activities j - acknowledging some annunciators ) l - clam flush PT i I - stroking CA pump turbine steam valves for I&E

- receiving phone calls concerning CA clam flush i activities

mJ 45 0 OATC gets assistance from STA - priority activities are decreasing { 45 - 60 o After review of logic drawings and ongoing CA

activities, switches are placed in "AUT0" , l t NOTE: At shift turnover (as1900) all annunciators and 1.47 Panel lights are analyzed by oncoming shift.

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4 WEAKNES8ES IL)ENTIFIED AND j . CORRECTIVE ACTIONS TAKEN l m , j , Y' Procedure i , Weaknesses ' o Fairly new procedure. Only perfomed once per month per unit ! ., - v " ' o' Step-stated " Ensure" instead of " Verify"

- ' , .;; ' o'Did not caution operator to significance of "AUT0" position f ,. - , t Corrective ~ Actions l . s -

o Procedure step was changed to' " Verify" t i o caution was added to proce, dure ' ' o Review of. control board switches and other procedures was conducted i, . , -{. s

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' WEAKNESSES IDENTIFIED AND ] CORRECTIVE ACTIONS TAKEN l Operator Weaknesses ' o Concern over lake water contamination of CA blocked the thought process on the " AUTO" position r o OATC did not immediately recognize these lights as " abnormal" and as a < , result did not take immediate action to notify the Control Room SRO or to ',' determine cause of the lights o OATC stated STA involvement would have occurred within a short, F period of time (within one hour)

Corrective Actions o operator was individually counseled t e Purpose and importance of "AUTC" position of these switches o Prompt assistance must be attained for unexpected 1.47 Panel lights o Immediate notification of the Control Room SRO must be made for all abnormal alarms and indications ' ! c Prior to performing a step, a full understanding of taking the ! specified action must be attained L o Operator update was distributed ' V y o Incident to be thoroughly covered in requal during let segment of next - t year j o More emphasis will be placed on the 1.47 Panel during classroom and l simulator training in the future

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. , .. ' WEAKNESSES IDENTIFIED AND ' .. <.,

CORRrCTIVE' ACTIONS TAKEN i

. , .

, < $ . . i 1.47 Bypass Panel , , i Weakn'ess

o Audibl'e alarm f eature was' not' functional .'{'t , o Reliability ' I.

< > Lo Not user friendly . ' . f ' ' e

Corrective Action I o Wrote' work requests to get audible alarm functional

o significant improv.iments in reliability has occurred over the last j > year , o Will pursue improvements that will make it easier and faster for the OATC to determine cause of lights . , . . '\\ I i ! w I 't It-I., l, t.

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. ,. .. ANNUNCIATORS VERSUS 1.47 PANEL LIGHTS . , 1.47 Panel Lights Annunciators o cause is not clear o cause' is clear o No audible alarm o Audible alarm , o Not reliablw in past o Reliable' o Trained to respond quickly o Not emphasized in training o Behind CATC o Face OATC o.Small, hard to read o Large, easy to read . O e

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,j, J CA OPERATION WHILE ) y SWITCHES WERE'" CLOSED" i o' All' normal' CA suction supplies were available and aligned to the CA pumps { u-o' AnnJnciator response ' for-" Loss of' Normal CA Suction" directs operator to '" ensure these valve have opened

t i o Emergency procedures direct operator on how to ensure a suction source is maintained as normal suction sources are depleted i t < i o Turbine driven pump would have been realigned for service within a two hour period of time after the governor valve was reinstalled ! .. . . E o CA Pung Turbine is protected from a loss of suction event due to the PT i-alignment !

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s s. 7 , m ,. e, s,.; lb..sI : ' ?, ' w . N' : [ ISSUES < , , i (

  1. 1 - Safety significance of having three CA pumps inoperable will be

, it discussed by.Greg;Swindlehurst '

,s < ' .

  1. 2 - RN'to CA piping flush procedure,was inadequate'

l t 4 ', , . l o Procedure stop was changed to " Verify" ) o Caution'was added to the procedure .. , i 'o other procedures' were reviewed and changed as necessary

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  1. 3 - Apparent lack of understanding of system design on the part of the

' r,3, DATC.

, o OATC had a good understanding of system design ' ' O OATC's concern over lake water contamination of CA caused a memory block of " Auto" function . , "o , o Procedure weakness was the primary reason for the mispositioning [ of the switches . I' o Individual was thoroughly counseled s' . o Update issued and roqual training for all operators , L .,. '

  1. 4 - OATC did not immediately notify the co-workers or the Control Room

' SRO and did not take Lumediate action to return the CA pumps to

service when the 1,47 Pansl lights were noticed o OATC did not immediately recognize the lights as " Abnormal" } !i o Usually need assistance to determine reasons for the lights

o When reason for lights was discovered, the Control Room SPO was notified and the switches were repositioned to Auto o operator priority of panel lights was not high enough i ! P .. l

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.

< l , SAFETY' SIGNIFICANCE -

1

, EVALUATION OF A FAILURE OF.THE TRANSFER.

! ' -

TO THE ASSURED SUCTION SUPPLY FOR THE- - AUXILIARY FEEDWATER SYSTEM ' - . % e BACKGROUND AND SCENARIO . e PROBIBILITY l

. L' s CONCLUSIONS \\

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L ' BACKGROUND AND SCENARIO . ' . i i THE. PURPOSE OF THE NUCLEAR SERVICE WATER CONNECTION TO THE AUXILIARY FEEDWATER PUMP SUCTION IS TO PROVIDE AN ! ASSURED SUCTION SUPPLY FOLLOWING A SEISMIC EVENT i ! i.

e A SEISMIC EVENT CAN RESULT IN: l

' LOSS OF NORMAL AFW SUCTION SOURCES -

STATION BLACK 0UT { - , .; . e THIS SCENARIO IS WITHIN THE DESIGN BASIS , , , L e: A FAILURE OF THE AUT0-TRANSFER TO THE ASSURED SUCTION r SUPPLY RENDERS THE AFW SYSTEM INCAPABLE OF MEETING THE

DESIGN BASIS .

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PROBABILITY ~ u , , t

' ! L e THE SAFE. SHUTDOWN EARTHQUAKE IS 0.15G

> . ' e THE NORMAL AFW SUCTION SUPPLY CAN WITHSTAND A , 0.3G EARTHQUAKE FROM A REALISTIC. PERSPECTIVE ' ' , . > e THE PROBABILITY OF AN EARTHQUAKE STRONGER THAN , $, 0.3G IS asl X 10-4/YR

.

e THE INADVERTENT VALVE ALIGNMENT EXISTED FOR ' 35 MINUTES e THE PROBABILITY OF THE EARTHQUAKE OCCURRING AND <1 LOSS OF AFW SUCTION IS ' f-s 1 X 10~4 X 1 HR EE 1 X 10-8

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.., _ - . . _.. _. - - m n ,c

' .. , ,. t l - r -

? CONCLUSIONS

s ! e NORMAL AFW SUCTION SUPPLY WAS AVAlLABLE THROUGHOUT THE [ , '

INCIDENT t i L e THE TRANSFER OF SUCTION T0 THE NUCLEAR SERVICE WATER L SYSTEM IS ONLY REQUIRED FOLLOWING A MAJOR EARTHQUAKE

e.THE PROBABILITY OF A MAJOR EARTHQUAKE OCCURRING L COINCIDENT WITH THE VALVE MISALIGNMENT IS NEGLIGIBLE I

l e IF THE SCENARIO 0F CONCERN OCCURRED, CORE COOLING COULD BE MAINTAINED VIA FEED AND BLEED (EP-2C1)

L e DUE TO THE EXTREMELY LOW PROBABILITY OF THIS SCENARIO, l AND THE AVAILABILITY OF A BACKUP CORE COOLING METHOD, - THIS INCIDENT IS NOT SAFETY SIGNIFICANT '

f -.... - - -. -.... ~.. .. . - .~.--------- ----------------! . --

.. _.

. ..._.

- . _ _. _. -... _.

_ _ _ i

1 4:;*> s < N r... c

, ., ENCLOSURE 4 i g p.

, .. , o.., _,

, , lt?, k.. I V: )i- ' p'. ! , I ' AGENDA g.; g.

NRC ENPORCBMENT CONFERENCE f UNIT 2 AUXILIARY PEEDWATER PUMP TURBINE (CAPT) OVERSPEED TRIP i [

, - r - DUKE POWER COMPANY

CATAWEA NUCLEAR. STATION OCTOBER.I1. I989 , \\

,

OPENING REMARES T.E.OWEN STATION MANAGER * CMS ' f t PHYRICAL DESCRIPTION OF CAPT W. R. TOMLINSON t MAINTENANCE ENOR BREVICES

SEQUENCE OF, EVENTS R. A. JdNES ( .. PART HISTORYi PRIOR TO JULY 31.'1989 MAINTENANCE ENOR BERVICES MOR . EVENTS ; JULY' It-AUGUST 7. !989 ROOT CAUSE/IMMEDIATE AND-W..R. McCOI' LUM LONG TERM CORRNCTIVE ACTION 8 surERiNTENbENT OF MAINTENANCE ANALYSIS OF SYSTEM PERFORMANCE G. E. SW!NDLERURST . , DESIGN ENGINEERINO

SUMMARY T.E,OWEN , a.

CLOSING REMAREB, J. W. HAMPTON MANAGER MUCLEAR REI.ATI' NS O , ! . . I e.

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, . .-. - -. _ _ - - - ..-. , u - ..f ,,-,. - -,

-

' ., i fl., , , ' -! - " - SA" SYSTEM DESCRIPTION . . - i ' "SA", MAIN STEAM TO AUXILIARY EQUIPMENT.

! - . l

.- AUX. FEEDWATER TURBINE ASSURES AUX. FEEDWATER AVAILABILITY

^

- STEAM TO OPERATE THE TURBINE IS DRAWN FROM TWO (2) MAIN STEA

FOR REDUNDANCY

, - .

- UPON SIGNAL TO START, SA2 AND SAS OPEN TO PROVIDE STEAM ' -i - SUPPLY LINES ARE HEAT TRACED TO PREVENT CONDENSATION , , P - AFTER 'STARTUP, CONDENSATE IS REMOVED BY AN ORIFICED DRAIN'NEAR TH TURBINE

,f.

. l . . i- . i-k - ... - ~ ..-..,.~,,. ,e,,,, ,,, - - -,,,,,, r,,, y ,-,_,.-,,,..,,,.-,.,,-.r,m...

.

. ,, _ _ _ .. _ . . _.. _ _ _... _. _. _ , .. ' ' . . u,' '- j . . r ! COMPONENTS OF THE SYSTEM ' , , " i - SA2 AND SAS ARE AIR OPERATED, BORG-WARNER, 4' GATE VALVES.

f . - TRIP AND THROTTLE VALVE IS A GIMPEL, 4' GLOBE VALVE WITH A ., LIMITORQUE OPERATOR, NORMALLY OPEN.

,. ! t - CONTROL VALVE IS A TERRY CORP./ DRESSER-RAND, 3' CONTROL VALVE AND IS CONTROLLED BY A PG-PL (MECHANICAL / HYDRAULIC) WOO .. --THE TURBINE IS A TERRY CORP / DRESSER-RAND, GS-2N WITH 1160 BHP.

ELECT. TRIP IS 4140 RPM ' MECH. TRIP IS 4500 RPM - GOVERNOR CONTROLS - CONTROLS ARE LOCATED IN THE CON

! THE LOCAL PANEL.

l . r . _... - -. - - , _.,,...,,.. _.., --.,,_.._.._.._..-...._..,...-.._.____________________ y.

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n- - L i ' y OPERATION , , j.' ' , l

SA2 AND SAS RECEIVE SIGNAL T0 OPEN.

i , c

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. 'WITHIN'4 TO 5 SEC. STEAM REACHES THE TURBINE.

H -

. a !

L 'uT - AFTER APPR0X.1.5 SEC. GOVERNOR STARTS TO CONTROL THE TURDINE.- ! o l o' 'AFTER APPR0X.:3 SEC.: l ' -

' ! - L ' FAST START RAMPS UP ' l ~

  • SLOW START DECREASING SPEED.

~ .

m.

! - -1AFTER APPROX. 6'SEC.: L i B

  • FAST' START STILL RAMPING UP i

L

  • SLOW-START REACHING MINIMUM SPEED.

t L '

AFTER APPR0X. 32 SEC.:

- ,u, ,

  • FAST START REACHING FULL SPEED.

,

  • SLOW START STABILIZING AT 1250 RPM.

> s ' .. e '

?& L - ALL OF CATAWBA NUCLEAR's TRIPS HAVE OCCURRED IN THE FIRST 1.5 SEC.

0F TURBINE ROLL.

THE FIRST 3 SEC. OF A FAST OR SLOW START ARE THE c SAME.

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.

.. > ly u -

~ n" SV' Ol25 ORIFICES, i SA8 X ' lw . .:.: ,,

' ORIFICE "O,o40 o <

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. 1-u y 1; CV) TURBINE H ' ^

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i DRAIN g j r ~ LINE

+1 l . ..

' i:- .. 0.020

~ ,. - ORIFICE ' h i , !

.. e*l 6.

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9r,

.; ... 7. x..: , s < , . -PAST HISTORY - PRIOR TO JULY 31, 1989 ! o'. - , .? 1; . . . A b i t f i GOVERNOR VALVE PROBLEMS THAT-HAVE BEEN SEEN AT' CATAWBA l t . % ' -l \\ ' UNIT 1:

s -

{ 's,

,I 11/84 - REPLACED DAMAGED STEM AND PACKING m & i ' ' ' pl t '

. M - 10/87'- REPAIRED PACKING LEAK ON GOVERNOR VALVE [

r,., ' ! , ..',. '. f.

01/89 - REPLACED PUMP ROTATING ELEMENT-(LER 413/89-007)

' ~

i

.o 'V DISCOVERED' GOVERNOR -VALVE LINKAGE BINDING DUE TO - PACKING LEAK WASHING OFF LINKAGE LUBRICATION

  • f-i I

i i , ', [ \\ , . .* f f ,3f5 p i( ' l-l , ,., t i y o' ,"yt -

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.,

... ,

. . .';;t ' , . ' i ' J.

UNIT!2:'- + . 2/88. >. BROKEN SNAP. RING CAUSED' GOVERNOR VALVE STEM BINDI! ..

3/89 - PREVENTIVE -MAINTENANCE lhSPECTION OF GOVERNOR VALVE ' ! , - PERFORMED' ' ,, , [[' ' '

' i - , i l'. > i n 'r.

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._.

. .__ -.. _ _ - _. _ ___ . _.. ,

. " . .;

. SUMMARY OF PAST llISTORY: '

- HAD SEEN LIMITED VALVE STEM CORROSION IN THE PAST ,

- CORROSION WAS NEVER SEVERE EN0 UGH TO CAUSE ANY OPERATIONAL I " PROBLEMS , i . , - IN ADDITION, CORROSION HAD OCCURRED OVER A FAIRLY LONG 'I - PERIOD OF TIME (0NE TO TWO YEARS) ! < - HAD NOTICED PACKING LEAK-0FF LINE ISOLATION VALVE TENDING TO ' CLOG 'UP OVER TIME AND HAD INITIATED ACTION TO REMOVE VALVE < FROM SYSTEM.

.P

l.

' - NO PAST HISTORY OF DOING SAFETY RELATED WORK AT CATAWBA

WITHOUT USING PROPER WORK CONTROL PROCESS (VERIFIED THROUGH SEARCH OF PROBLEM INVESTIGATION REPORTS AND LER's)

! i.

' , , . . . -. . . - -. -. - . - - - -

_ . . . _.. _-. .. ., p [" . SEQUENCE OF EVENTS y., JULY 31, 1989 TO AUGUST 7, 1989 l MONDAY,' JULY 31ST - U2 CAPT TRIPS ON MECHANICAL OVER-SPEED , - MES STAFF ENGINEER INVOLVEMENT ! --OPERABILITY DETERMINATION ' . i - FACTORS T0: CONSIDER . ' TUESDAY, AUGUST.1ST

L - MES MANAGEMENT REVIEW 0F PROBLEM i i - PLAN OF ACTION ESTABLISHED TO INVESTIGATE LONG TERM ! IMPLICATIONS ' , ~ - RE-EVALUATION OF PUMP OPERABILITY i ' ! ! WEDNESDAY,-AUGUST 2ND j ! - STATION MANAGEMENT REVIEW 0F PROBLEM . - DISCUSSIONS WITH VEND 0R i , - LUBRICATION ISSUE ! , + - PLAN OF ACTION CONCERNING LINKAGE LUBRICATION - UNIT 1.CAPT VISUAL INSPECTION PERFORMED .. -- ., _ . .. - -- _ - - - _ _ - - _ _ _ _ _ _ _ _ _ _ _ _,

, , ., ,v i t w.- -, . ' THURSDAY, AUGUST 3RD

' [ s .. i "

- ESTABLISHED SCHEDULE FOR PREVENTIVE CLEANING / DISASSEMBLY OF ! ,, , UNITS 1 s 2 CAPT GOVERNOR VALVE LINKAGES

. FRIDAY, AUGUST.4TH i '

dH - MEETING WITH-STATION GROUPS TO OUTLINE WEEKEND WORK SEQUENCE L .,

s

- MEETING WITH NRC AND MAINTENANCE MANAGEMENT i ' f ' SATURDAY, AUGUST STH

, L

L' - SUCCESSFUL PRE-MAINTENANCE START ON UNIT 1 CAPT ! H '

, , f SUNDAY, AU6UST 6TH n

' . =- UNIT 1~ CAPT. LINKAGE CLEANED, RELUBRICATED, AND SUCCESSFULLY RETESTED'

. m.

. MONDAY, AUGUST 7TH o s - UNIT

CAPT TRIPS ON ELECTRICAL OVERSPEED DURING t ' PRE-MAINTENANCE START, SECOND START ATTEMPI IS SUCCESSFUL ' . - BEGAN GOVERNOR LINKAGE DISASSEMBLY - DISCOVERED VALVE STEM CORROSION PROBLEM i m.. .... . .. .. .. .. ... . . .. . . . . . .. .

' - ! .r ' - ,

,

. i ,. .. , ., TUESDAY, AUGUST 8TH . . COMPLETED REASSEMBLY OF GOVERNOR VALVE ! . - ! REMOVED INTERNALS FROM PACKING LEAK-0FF LINE lSOLATION VALVE - - TO AID ~IN DRAINING OF MOISTURE i " POST MAINTENANCE RETEST WAS SUCCESSFUL -

, ? f, x i . ! -. - , ,__ _ _ ._ _ _ _ _. _,,, _ _. . . .. . . -

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.-c.

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PROBLEM AREA: , 't.

i [ f.

' FAILURE TO USE WdRK REQUEST PROCESS TO

' TCONTROL. WORK ON JULY 31, 1989.

y

L N,

' i L.',. L7' ROOT CAUSE: ~ . l

M - MES STAFF ENGINEER FAILED TO INITIATE i o* WORK REQUEST PRIOR TO EXERCISING LINKAGE.

p i <. -

m

.; . ' s o ' s J < g

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  • !

l: L l., l' .., , . ' e*Me we he v-Wwme lir a w-ww-w y w r--wg-ew k ww w-y--,-- w-t - - -wew e-- en--w3-we r-- er,, w w ap,,i,--e w yw,yed-iw , e ye-wwg .y,,, - -ry,--tv w w w -+e e,w--- w ---D ww-" r

. . ._ ~ .... _... - --...- -. . .. 'A,- , .r 'h s' - s.

, .: ' ' j . in CORRECTIVE ACTIONS: . ' tt . 'MES STAFF ENGINEER COUNSELLED.

' STATION MANAGER STAFF NOTES DISCUSSED .c THROUGHOUT ORGANIZATION: q ' ' > , ' EMPHASIZED NEED TO FIND ROOT CAUSES.

< u-x- 'NEED TO USE PROPER PROCESSES.

i ' . 'MES SECTION MANAGER MET WITH SECTION l MEMBERS: LA t + DISCUSSED NEED TO USE APPROPRIATE WORK i , ' + " CONTROL PROCESS.

\\ + DISCUSSED NEED TO BE SENSITIVE TO i FINDING REAL ROOT CAUSE.

< .- , + REINFORCED NEED TO INVOLVE ENGINEERING i SUPERVISORS IN SAFETY-RELATED OPERABILITY

DECISIONS.

'l l

0 , r4" - - -'vv-*'--- ---+--***+-****-eve r

  • - - = ' - - * - *~

~ -- - -- - * ~ - -'------ - - - - - - - - - - - -

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- PROBLEM AREA:

m , . BINDING OF GOVERNOR VALVE z , . a, . . L .j

.; ROOT CAUSE: .

i s.. CORROSION.OF NITRITED' LAYER OF 410-STAINLESS STEEL-VALVE STEM.

m .1 f ',, t iI

b.

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< .- , . ) - .

IMMEDIATE i CORRECTIVE ACTIONS:

t 'NEW GOVERNOR VALVE STEM WAS INSTALLED.

ON UNIT 2.

' t ' MOISTURE DRAIN PATH WAS IMPROVED BY IMMEDIATELY REMOVING DRAIN LINE VALVE , l - INTERNALS, THEN SUBSEQUENTLY MODIFYING DRAIN LINES TO DELETE VALVES.

'

1 ' COMPENSATORY ACTION TO PERFORM LINKAGE [ AND PACKING DRAG TEST AND START TEST Y OF PUMP ON 2 WEEK INTERVAL WAS PUT INTO . . PLACE.

,

~ , t l D l " L L

L . _ _. _... _.. _ - -.., _... - _.. _. - ~. _ _. _. _ - . -

._ _ _ .. _ _ - . . _ .. . . ._.. . - , .. i , t-

l 8-

, .. . - - l

.

- ,

. E.L.

I t 'l

, - PERFORM MODIFICATIONS TO INCREASE RELIABILIT: ' 0F DRAINAGE FLOW PATHS.

z t . - - PERFORMED ON BOTH UNITS " - REORIENTED-LEAK-OFF LINE ! ? L - DELETED' LEAK-OFF LINE ISOLATION VALVE .

, . MODIFIED STEAM SUPPLY VALVE STROKE TIME ,

- SLOWED DOWN VALVE STROKE TIME L I - ALLOWS SLOWER RATE OF STEAM ADMISSION

TO TURBINE - EASIER FOR GOVERNOR TO CONTROL

3-i i l

. ' I t, I ' I '. t

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, - . . . .. .. - , , y.y.. , , N* 5.

._ ',. G ! ' , , t q FOLLOW-UP ACTIONS: . ' . PERFORM PACKING. DRAG TESTS EVERY TWO e WEEKS AND TREND RESULTS.

- SUCCESSFUL LINKAGE / PACKING-DRAG TEST-i ' PERFORMED ON BOTH UNITS l , > ' . - 3 ON UNIT 1 l'l - 2 ON UNIT 2

- TESTS HAVE SHOWN NO INCREASE IN DRAG' FORCE f GOVERNOR VALVE STEM INSPECTIONS u - INSPECTED VALVE. STEMS ON BOTH UNITS . - MINIMAL CORROSION ON UNIT 1 STEM (HAD BEEN IN SERVICE FOR 2 YEARS) - NEGLIGIBLE CORROSION ON UNIT 2 STEM ' (DISCOLORATION) , ... . e n.+ s .,-.,,. _,. ,..,n,.,,.,,,,,,,-,,,,.,,,en,,, , -. ,n,., ,,,e.,. ,-,, n .- .

- - ._ . __ . - _ - -- - - - - - .. .,. .. . . - . . i '3-LONG - TERM ACTIONS: i l !l ' INITIATED AUX FEED PUMP WORKING GROUP k TO DEVELOP LONG TERM ACTION PLAN TO ENHA RELIABILITY: (SIMILAR TO D/G EFFORTS) ! A.

LINKAGE AND GOVERNOR CONTROL \\ ' ' , ! - B.

GOVERNOR VALVE i, ! STEAM SUP;)LY AND DRAINAGE PATHS.

! c.

I D.

MATERIALS AND COMPONENT CONCERNS.

E.

PROCEDURES F.

TRAINING t i ! INCREASED ATTENTION TO TIMING OF G.

! ! aux. FEED PUMP STARTUP AFTER PACKING DRAG TEST.

l , !

> . . -... . - -. . _. _ _ . . - . . - . . -... .. ~ -

. l (

  • :,.

. ,

1, o

- . , - .

b " i I

- ' ! SAFETY SIGNIFICANCE l i l ' !

! i L ANALYSIS OF THE IMPACT OF A ! l DEGRADED AUX 1LIARY FEEDWATER SYSTEM L ON THE LIMITING FSAR TRANSIENT ' , I ' e BACKGROUND . e WORST CASE SCENARIO I ! e ANALYSIS METHODOLOGY

. t e RESULTS j ! e CONCLUSIONS

! > ! i ! L f ! ! , t . - -_ _ - .-. ., -. -,,.

. '. -

. BACKGROUND L i e FSAR STATES THAT AT LEAST TWO STEAM GENERATORS CAN BE SUPPLIED WITH A MINIMUM 0F 490 GPM OF AUX 1LIARY FEEDWATER e THE DEGRADED SITUATION RESULTS IN N0 AUXlLIARY FEEDWATER IMMEDIATELY AVAILABLE - ONE MOTOR-DRIVEN PUMP INOPERABLE i - ONE MOTOR-DRIVEN PUMP ASSUMED LOST AS THE LIMITING SINGLE FAILURE , - THE TURBINE-DRIVEN PUMP TRIPS ON OVERSPEED e LESS AUXILIARY FEEDWATER FLOW THAN ASSUMED IN THE FSAR CHAPTER 15 TRANSIENT AND ACCIDENT ANALYSES, e OPERATOR ACTION REQUIRED TO RESTORE ADEQUATE AUXILIARY FEEDWATER FLOW i

. e' '.

l..* ' WORST CASE SCENARIA , n ! i h THE LIMITING SCENARIO IS A MAIN FEEDWATER LINE BREAK IN e EITHER STEAM GENERATOR 'B' OR 'C' , l ALL MAIN FEEDWATER LOST AT TIME ZERO - ALL FOUR STEAM GENERATORS BLOW DOWN - i UNTil MSIV CLOSURE ON LOW STEAM LINE PRESSURE NO AUXlLIARY FEEDWATER IMMEDIATELY - AVAILABLE e OPERATOR ACTIONS , ISOLATE AUXILIARY FEEDWATER TO THE - FAULTED STEAM GENERATOR (0-600 SECONDS) RESTART TURBINE-DRIVEN AUX 1LIARY - FEEDWATER PbMP (600 SECONDS) - PROVIDES A MINIMUM FLOW 0F 298 GPM TO ONE STEAM GENERATOR AllGN TURBINE-DRIVEN PUMP TO A SECOND - , STEAM GENERATOR (900 SECONDS) - PROVIDES A MINIMUM FLOW 0F 554 GPM REC 0VERY ACTIONS INVOLVE THROTTLING - AUXILIARY FEEDWATER FLOW AND TERMINATING SAFETY INJECTION . i

p -

c !. o - -

, ,- i c

.. . ' i , ! ': ANALYSIS METHODOLOGY ! '

' s PLANT-SPECIFIC SIMULATION OF THE WORST CASE SCENARIO USING l A THREE-LOOP CATAWBA UNIT 1 RETRAN-02 MODEL ! ! e BOUNDARY CONDITIONS

! ! MAIN FEEDWATER LINE BREAK TO EITHER STEAM l - GENERATOR 'B' OR 'C' l , .. ' NO AUXILIARY FEEDWATER UNTil 600 SECONDS - AUX 1LIARY FEEDWATER FLOW FROM 600-900 . - SECONDS CORRESPONDING TO FLOW TO ONE STEAM l GENERATOR AUXILIARY FEEDWATER FLOW FROM 900-2400 - i SECONDS CORRESPONDING TO FLOW TO TWO STEAM ! GENERATOR

! REALISTIC HIGH DECAY HEAT I - L ! l

!

I I ! . I I .r.

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. ... . .' I ' * ! \\ l RESULTS i , i SEQUENCE OF EVENTS ! . T!ME (SEC) EVENT ! O FEEDWATER LINE BREAK

2.6 PZR SPRAY ON

'14.5 RX TRIP ON LOW-LOW SG LEVEL 14.7 TURBINE TRIP .l 15.8 PZR SPRAY OFF i 16.7 PZR HEATERS ENERGlZE ' ' '181 SAFETY INJECTION ON LOW PZR PRESSURE . 191 NV AND NI PUMPS START t 300 MINIMUM RCS PRESSURE = 1816 PSIG '392 MAIN STEAM ISOLATION ON LOW SG PRESSURE [ L '490 SPDS RED ALARM - LOSS OF HEAT SINK l 554 PZR HEATERS OFF i 563 PZR SPRAY ON f L '600 TD AUX FDW PUMP STARTED

900 TD AUX FDW PUMP ALIGNED TO SECOND SG l

  • 1490 PZR WATER SOLID

1496 PZR PORVS BEGIN CYCLING - - 1596 MAIN STEAM SAFETY VALVES BEGIN CYCLING l l 2400 END OF SIMULATION [

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o . _ i e i !, ~ CNS FWLB WITH TD AUX FDW @ 600 SEC i -

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  1. #**

u,"' ' , l I ! l ) ! CONCLUSIONS ] ! ! e UNIT STATUS AT 40 MINUTES IS NOT SERIOUSLY DEGRADED [- RCS IS WATER SOLID WITH S1 INJECTING

- AUX FDW FLOW IS BEING SUPPLIED TO TWO

- L STEAM GENERATORS IN EXCESS OF DESIGN l REQUIREMENTS - RCS T-AVE IS 570 F AND HAS BEEN STABLE j

' - FOR TEN MINUTES

i e UNIT REC 0VERY TO ATTAIN NORMAL POST-TRIP CONDITIONS CAN ! ' PROCEED ! e ALTHOUGH THE DESIGN BASIS AUXILIARY FEEDWATER FLOW

REQUIREMENT WAS NOT MET FOR FIFTEEN MINUTES, THE PLANT TRANSIENT RESPONSE DID NOT APPROACH ANY SAFETY LIMITS -

, > , E $ L -,. _ -,,,, ,. . -, -. _. _ . -.., _,,., - - - _ _ _ _ _. _ _. _. _ - _. - - _ _ _ - - - - - _ _ - _. }}

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