ML17328A445
| ML17328A445 | |
| Person / Time | |
|---|---|
| Site: | Cook  |
| Issue date: | 09/13/1990 |
| From: | Colburn T Office of Nuclear Reactor Regulation |
| To: | Office of Nuclear Reactor Regulation |
| References | |
| NUDOCS 9009240079 | |
| Download: ML17328A445 (33) | |
Text
UNITED STATES NUCLEAR REGULATORY COMM(SSION WASHINGTON, D. C. 20555 September 13, 1990 Docket No. 50-315 and 50-316 LICENSEE:
Indiana Michigar: Power Company FACILITY:
Donald C. Cook, Units 1 and 2
SUMEC7:
THIMBLE TUBE INSPECTION RESULTS MEETING
SUMMARY
On August 29, 1990 from 8:30 a.m. until 10:30 a.m. representatives of Indiana Michigan Power Company (licensee),
1!estinghouse Electric Corporation (NSSS vendor) and Cramer 8 Lindell (corItractor for the licensee) met vrith members of the staff and cur consultant Brookhaven NatiorIal Laboratory to discuss the results cf a recent eddy current inspection of the D. C.
Cook Unit 2 thimble tubes anc'the implicatiorI of those results on current Unit 1 operatiorI and upcon;ing Unit 2 Cycle 8 operation.
A list of attendees is corItained in Enclosure 1.
Region III representatives atterIded by teleconference.
A copy Gf slides shown during the licensee's preserItation is included as Enclosure 2.
The staff requested this meeting with the licerisee to discuss the apparent "accelerated" v,ear evidenced on the thimble tubes at D. C.
Cook Unit 2 as reported by the licensee.
All thiIrble tubes for both D. C. Cook Units 1 and 2
had been replaced during the previous refueling cutage for each urIit.
This was due to aggressive wear observed on the thimble tubes as a result of eddy current inspections conducted during those refueling outages.
The cause of the vrear appear's to be flew-induced vibration fretting.
The licerIsee provided the results of a finite element ar,alysis corIducted by MestiIIghcuse to evaluate the viorn thimble tubes.
Based on the results of the ar;alysis, which were verified by preliminary collapse test data, the licensee corIcluded that t,himble tubes with up to 65% peak wall loss Iray be kept in service provided further wall loss is prevented.
This could be done by axially repositiorIirIg the thimble tubes to realign wear surfaces to a location which is free of wear.
The licensee ccmnIitted as short term corrective actions, to replace 10 thimble tubes, axially reposition 19 other thinible tubes and reexamine all thimble tubes in Unit 2 at the rIext refueling outage.
The staff solicited an additional connIitmerIt tc ccnsider reexamining Unit 2 thimble tubes prior to the next refuelirIg cutage if (1) an outage of sufficierIt. duration were to occur prior to the refuelirig outage and (2) if the results of UrIit 1 eddy current testing or Unit 2 operational experience indicated that such an earlier reexarr:ination of UrIit 2 thimble tubes would be warranted.
The licensee also coneIitted to provide the staff with the UrIit 1 eddy current test results following the upcoming Unit 1 refueling outage.
9009240079 900913 PDR ADOCK 05000315 0
'l f~
complete with their analysis in early 1991.
The licensee committed to provide the staff with the results of their root cause analysis and long term recommendations as soon as they are available.
Th t ff 1
d d that the licensee's analysis to date resolved any concerns for operation of Unit 1 until the scheduled refueling outage and or p
esa concue f r o eration 0
nl f U 't 2 during the upcoming Cycle S.
The staff further agreed that the licensee's short term corrective actions and root cause analysis app roach appeared reasonable.
Enclosures:
1.
List of Attendees 2.
Iteeting slides cc:
See next page DISTRI BUT ION DDDCKET FILE NRC 8
LOCAL PDRs Fl<IRAGLIA JPARTLOH DCRUTCHFIELD RPIERSON OGC EJORDAN ACRS(10)
JCLIFFORD TCOLBURN JZMOLINSKI PD31 R/F SIPEADOR NRC ATTENDEES
/s/
Timothy Colburn, Sr. Project Vianager Project Directorate III-1 Division of Reactor Projects III, IV, V 5 Special Projects LA/PD31:D S SNEADOR 9/(/90 Pl</PD31: DRSP TCOLBURN 9/g /90 D/P
- DRSP RPI ON 9/')5/90 COOK NTG.
SUf4lf<ARY ",
GF~
~lt,
)
C 1
k I
The licensee also discussed the preliminary results of their root cause analysis of the accelerated wear phenomenon.
The licensee indicated that it was investigating a number of potential
- causes, some generic to the thimble
- tube, some specific to Unit 2 design and indicated that they expected to be complete with their analysis in early 1991.
The licensee committed to provide the staff with the results of their root cause analysis and long term recommendations as soon as they are available.
The staff concluded that the licensee's analysis to date resolved any concerns for operation of Unit 1 until the scheduled refueling outage and for operation of Unit 2 ouring the upcoming Cycle 8.
The staff further agreed that the licensee's short term corrective actions and root cause analysis approach appeared reasonable.
Enclosures:
1.
List of Attendees 2.
Vieeting slides Timothy Colb rn, Sr. Project Hanagel Project Directorate III-1 Division of Reactor Projects III, IV, V & Special Projects cc:
See next page complete with their analysis in early 1991.
The licensee comitted to provide the staff with the results of their root cause analysis and long term recommendations as soon as they are available.
The stzff concluded that the licensee's analysis to date resolved any concerns for operation of Unit 1 until the scheduled refueling outage and for operation of Unit 2 during the upcoming Cycle 8.
The staff further agreed that the licensee's short term corrective actions and root cause analysis approach appeared reasonable.
Enclosures:
1.
List of Attendees 2.
Vieeting slides cc:
See next page DISTRIBUTION DOCKEl FILE NRC 8 LOCAL PDRs FhIRAGLIA JPARTLOIJ DCRUTCHFIELD RPIERSON OGC EJORDAH ACRS(10)
JCLIFFORD TCOLBURN J Zl<OLI ASKI PD31 R/F SKEADOR NRC ATTENDEES
/s/
Timothy Colburn, Sr. Project Banager Project Directorate III-1 Division of Reactor Projects III, IV, V 5 Special Projects LA/PD31: D S
SI~EADOR 9/(/90 PN/PD31: DRSP TCOLBURN 9/g /90 D/P,
.:DRSP RPI ON 9/ )s/90 COOK (4TG.
SU)~VARY
~
Mr. Milton Alexich Indiana Michigan Power Company Donald C.
Coo k Nuclear Plant CC:
Regional Administrator, Region III U.S. Nuclear Regulatory Commission 799 Roosevelt Road Glen Ellyn, Illinois 60137 Attorney General Department of Attorney General 525 West Ottawa Street Lansing, Michigan 48913 Township Supervisor Lake Township Hall Post Office Box 818 Bridgman, Michigan 49106 Al Blind, Plant Manager Donald C.
Cook Nuclear Plant Post Office Box 458 Bridgman, Michigan 49106 U.S. Nuclear Regulatory Commission Resident Inspectors Office 7700 Red Arrow Highway Stevensville, Michigan 49127 Gerald Charnoff, Esquire Shaw, Pittman, Potts and Trowbridge 2300 N Street, N.W.
Washington, DC 20037 Mayor, City of Bridgman Post Office Box 366 Bridgman, Michigan 49106 Special Assistant to the Governor Room 1 - State Capitol Lansing, Michigan 48909 Nuclear Facilities and Environmental Monitoring Section Office Division of Radiological Health Department of Public Health 3500 N. Logan Street Post Office Box 30035 Lansing, Michigan 48909 Hr. S. Brewer American Electric Power Service Corporation 1 Riverside Plaza
- Columbus, Ohio 43216
Enclosure I LIST OF ATTENDEES NAME TIHOTHY COLBURI<
ROBERT PIERSON JOkH RAMSEY TAD tlARSH SHOU-HI EN HOU TERENCE CHAN GEORGE GEORGIEV CL1FFORD SELLERS GJLIAHO DeGRASSI BRttCE BURGESS
)i'AYttE DANIELSOH STEVE BREWER N VID VAIL DEUSEH DOUG tlALIt'AN)FL t'IERKOUSKY RAt'DY KEPPLER ALBER10 VERTERAflO LEE S1ERt'hRISllt/k VERTAS 1! ILLlAt'RAt'kk ORGANIZATION NRC/NRR/PD31 NRC/HRR/PD31 NRC/NRR/OGCB NRC/NRR/EthEB NRC/HRR/EYiEB NRC/NRR/EttEB HRC/NRR/EtiTB NRC/NRR/EYiCB HRC/BROOKHAVEH NATIONAL LAB NRC/REGION III HRC/REGION III AEP/NS8L AEP/NUCLEAR FUELS 5 At!ALYSIS AEP/NUCLEAR FUELS 8 ANALYSIS 1JESTINGHOUSE/ttATD/t'lECH ~
EQUIP DESIGN INP/DC COOK/REACTOR ENG.
ll'1P/DC COOK/REACTOR ENG.
SECT.
SUPV.
WESTIHGPiOUSE/PROJkCT ENGINEER VEST INGkOUSE/PLANT LI CENSING CRAtiER 5 Lit<DELL ENGINEERS INC.
BO TOM MOUNTED INSTRUMENTATION FLUX THIMBLE MfEAR DONALD C. COOK NUCLEAR PLANT AUGUST 29, 1990
~ 'f(
~
~
UNIT 2 THIMBLE TUBE WEAR ISSUE o
AGGRESSIVE WEAR OBSERVED o
ALL THIMBLE TUBES REPLACED LAST REFUELING o
- UPGRADED, LARGER THIMBLE TUBE DESIGN o
THIMBLE TUBE LEAK DETECTED END OF CYCLE 7 o
'EDDY CURRENT TESTING INDICATED APPARENT ACCELERATED WEAR
t
REPLACE
$ 0 TUB~
AXtALLY REPOSlTION 19 TUBES EXAMtNE TUBES AT NEXT REFUELING OUTAGE
THIMBLE TUBE EDDY CURRENT EXAMINATIONRESULTS THIMB1E TUBE PERCENT WEAR THROUQH 100%
>90%
60%<X<90%
40%<X<60%
NUMBER OF THtMBLFTuSZS 18
PROVIDES NEtLIIf NEAR SURFACE
@NORW TUBES Cm VriTHSTAHO PRESSURE
REPOSlTIONING FINlTE ELEMENT ANALYSES (MED-PCE-9428)
Dt=MQNSTRATE STRENGTH OF TUBE VflTH 66% NV.L LOSS EXTERNAL PRESSURE OF 2g00 PSl PEAK STRESS INTENSITY 26,236.6 Pal ASME BOILER AND PRESSURE VESSCt. l.ODF CISE H-6O-S 26,700 Pal
- THIV)BLE CLASSIFICATION AND DESIGN INITIAL THIMBLE DESIGN 'IN ACCORDANCE WITH THE DESIGN FOR EXTERNAL PRESSURE RULES OF SECTION III, NC-3000 WORN THIMBLES ARE EYALUATED USING FINITE ELEMENT ANALYSIS ANALYSIS PERFORMED USING A 2-D MODEL MODEL REPRESENTS A 180 DEGREE SEGMENT THE SCAR COYERS A TOTAL ARC OF 108
- DEGREES, WITH A MAXIMUMWALL LOSS OF 65'o
0 EXTERNAL PRESSURE OF 2500 PSI RESULTS IN A MAXIMUMMATERIAL STRESS INTENSITY OF 25235.5 PSI VERSUS A MATERIAL ALLOWABLE OF 25700.0 PSI
l,'br i ab 1c-SIHT 1~v., -25235. 5 t1in.=1838.69 j~t'l
<t
~ ~
rt)L 25235.5 23511.4 21782. 9 20654.3 1 A3?6.
16597.
1 14868. 6 13148.
11411.4 9682.86 7954.29 C~225,71 4497.'14 2768.57 18%0, fry A
S
~
l
4
~
~o r
CS AMERICAN ELECTRIC POWER BOTTOM MOUNTEO INSTRUMENTATION THIMBLE WEAR 3S eoO 30 CO 60 70 HalfAngle Degrees
~ 60% ~ 65% ~ 70% ~ 75%
~
~
0
~
THIMBLE REPOSITIONING IN ORDER TO MAXIMIZE THIMBLE LIFE, IT MAY BE NECESSARY TO REPOSITION A THIMBLE AFTER IT HAS BEGUN TO WEAR REPOSITIONING MOVES THE WEAR SCAR AWAY FROM THE SURFACE ON WHICH IT HAS BEEN WEARING rI SURFACE IN THE WEAR LOCATION BASED ON FINITE ELEMENT ANALYSIS RESULTS, IT IS ACCEPTABLE TO KEEP THIMBLES WITH UP TO 65:
WALL LOSS IN SERVICE, IF FURTHER WEAR IS PREVENTED.
~,
~ 4
~'
FEA RESULTS HAVE BEEN VERIFIED BY PRELIMINARY COLLAPSE TESTING CONDUCTED FOR THE WESTINGHOUSE OWNER'S GROUP TUBE WITH 0.002" REMAINING WALL (>90>a WALL LOSS)
WITHSTOOD 8000PSI BEFORE COLLAPSE, IT DID NOT RUPTURE TUBE WITH 0.013" REMAINING WALL (74'o WALL LOSS)
COLLAPSED AT A PRESSURE OF 13,600 PSI.
FURTHER PRESSURIZATION TO 17,140 PSI DID NOT RESULT IN ANY LEAKAGE
0 SUBSEQUENT ECT INSPECTION RESULTS HAYE CONFIRMED THAT REPOSITIONED WEAR SCARS DO NOT INCUR ADDITIONALWEAR
l c~
~
PLANT 1 - '4 LOOP, 0.300" THIMBLE, 0.468" COLUMN
SUMMARY
OF THIMBLES WITH >191'ALL LOSS AFTER 1 CYCLE CORE LOCATION J7 Hl1 DB K12 H13 CS L13 K2 F14 N13 R6 All N14 CYCLE 1 20 20 30 20 20 20 30 20 26 20 26 20 23 CYCLE 2 CYCLE 4 33 28 19
<20 38 36 19
<20 19 0
18 20 48 48 22
<20 24
<20 22
<20 16 25 15
<20 37 37
D. C. COOK NUCLEAR PLANT HAS INITIATED A PROACTIVE PLAN FOR ADDRESSING THE FLUX THIMBLE TUBE WEAR ISSUE NEW UPGRADED THIMBLES INSTALLED FOR BOTH UNITS SPARES ON SITE REPLACEMENT AND REPOSITION IN PROGRESS E/C TESTING AT REFUELING OUTAGES LONG TERM ACTIONS UNDER CONSIDERATION I
UNIT 2 CONDITIONS ANF FUEL, NEVf THIMBLES SLIGHTLY DIFFERENT FLOVf FROM HEN STEAM GENERATORS SMAt.L OEBRIS (6 X1 X 5l8)
ROOT CAUSE SCHEDULED OCT 1990 UNIT 1 TEST RESULTS VIDEO CONF IRMATION COLO SEGHENT VETALmmHV SAHPLES TAKEN HOT SEGMENT HETALLOGRAPHY SAHPLES TAKEN SEGREGATED STORAGE SHIPHENT EXPECTED NEXT MEEK FUEL GUIDE TUSE INSPECTION
~.
POTENTIAL SOLUTIONS SLEEYE EXTENSIONS THICKER THIMBLE TUBES OTHER
I I
0 SAFETY CONSlDERATIONS A FLUX THIMBLE LEAK, IF IT VfERE TO OCCU IS NOT A SIGNIFICANT SAFETY CONCERN LOVf LEAK RATE CAPABILITY OF ISOLATING THE LEAK VflTH EXISTING ISOLATION VALVES THE FLUX THIMBLE VfILL DEVELOP A FLUID LEAK BEFORE A GUILLOTINE BREAK OCCURS DEMONSTRATED BY LEAKS THAT OCCURRED IN U.S. AND EURO< E (<4)
UNIT 2 CAN BE SAFELY OPERATED UNTIL THE NEXT SCHEDULED REFUELING OUTAGE %HEN EVALUATION NILL BE PERFORMED AGAIN
CONCLUSION UNIT 2 CAN BE SAFELY OPERATED UNTIL THE NEXT SCHEDULED REFuELING OUTAGE NHEN TESTING AND EVALUATION VfILL BE r ERFORMEO PGAIV