IR 05000413/1989025
| ML19325E154 | |
| Person / Time | |
|---|---|
| Site: | Catawba  |
| 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) | |
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
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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
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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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' .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 , ,'
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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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' 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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, < $ . . 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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- 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'
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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- 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 .,. '
- 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
YR 8760 h3/YR t f t , _,,,, ,,m.
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? 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 '
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, ., ENCLOSURE 4 i g p.
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NRC ENPORCBMENT CONFERENCE f UNIT 2 AUXILIARY PEEDWATER PUMP TURBINE (CAPT) OVERSPEED TRIP i [
, - r - DUKE POWER COMPANY
CATAWEA NUCLEAR. STATION OCTOBER.I1. I989 , \\
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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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' ., i fl., , , ' -! - " - SA" SYSTEM DESCRIPTION . . - i ' "SA", MAIN STEAM TO AUXILIARY EQUIPMENT.
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.- AUX. FEEDWATER TURBINE ASSURES AUX. FEEDWATER AVAILABILITY
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- STEAM TO OPERATE THE TURBINE IS DRAWN FROM TWO (2) MAIN STEA
FOR REDUNDANCY
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- 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
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. ,, _ _ _ .. _ . . _.. _ _ _... _. _. _ , .. ' ' . . 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.
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. 'WITHIN'4 TO 5 SEC. STEAM REACHES THE TURBINE.
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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.
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! - -1AFTER APPROX. 6'SEC.: L i B
- FAST' START STILL RAMPING UP i
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- SLOW-START REACHING MINIMUM SPEED.
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- 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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' ORIFICE "O,o40 o <
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i DRAIN g j r ~ LINE
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~ ,. - ORIFICE ' h i , !
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.; ... 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
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UNIT!2:'- + . 2/88. >. BROKEN SNAP. RING CAUSED' GOVERNOR VALVE STEM BINDI! ..
3/89 - PREVENTIVE -MAINTENANCE lhSPECTION OF GOVERNOR VALVE ' ! , - PERFORMED' ' ,, , [[' ' '
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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 -
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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.
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. . ._ ~ .... _... - --...- -. . .. '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.
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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.
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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.
,
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._ _ _ .. _ _ - . . _ .. . . ._.. . - , .. i , t-
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, - 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
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._ ',. 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.
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- ' ! 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 -
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.. . ' 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
!
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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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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 -,. _ -,,,, ,. . -, -. _. _ . -.., _,,., - - - _ _ _ _ _. _ _. _. _ - _. - - _ _ _ - - - - - _ _ - _. }}