ML20055E249

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Summary of 900625 Meeting W/Util & C-E Re Control Element Assembly Failures & Corrective Actions.Major Topics Presented Listed,Including Visual Exam Results & Fuel Insp Activity & Results.List of Attendees & Briefing Matls Encl
ML20055E249
Person / Time
Site: Maine Yankee
Issue date: 07/05/1990
From: Leeds E
Office of Nuclear Reactor Regulation
To:
Office of Nuclear Reactor Regulation
References
NUDOCS 9007110215
Download: ML20055E249 (60)
v • d • e


Text

{{#Wiki_filter:W {, i y < -, July 5,1990 ,~ c, - ,_s 1 Docket No. 50-309 LICENSEE: Maine Yankee Atomic Power Company FACILITY: Maine Yankee Atomic Power Company

SUBJECT:

MEETING

SUMMARY

ON CONTROL ELEMENT ASSEMBLY FAILURES AND CORRECTIVE ACTIONS On June 25,1990, the NRC staff met with representatives of Maine Yankee and Combustion Engineerin elementassemblies(CEAs)gtodiscusstherecentfailuresofseveralcontrol at Maine Yankee and the licensee's corrective actions. The licensee's presentation included the following major topics:

1. The CEA Surveillance Program
2. The CEA Replacement Program
3. The Discovery sf the Failed CEA
4. The Eddy Currt it Exam Results
5. The Visual Exatination Results
6. The Fuel Inspection Activity and Results
7. Plans for Cycle 12 Operations

'A copy of the licensee's briefing material and a list of meeting attendees-is enclosed. Eri 0. Lee 8s"PrjectManager Project Directorate I-3 Division of Reactor Projects I/II

Enclosures:

As stated cc w/ enclosures: See next page 7 PDI-3 ( /DIR MR(sjbro, Ele ,mw i/pec / /90 ~~/ 90 /90 1 0FFICIAL RECORD COPY Document Name: MTG.

SUMMARY

6/25/90 MAINE YANK /DI Y, 1 78R72 = M Mc&7' e P PDC

Enclosure i i BACKGROOND CEA DESIGN CEA MEASUREMENTS CEA REPLACEMENT PROGRAM DISCOVERY OF FAILED CEA .h l l l. l l-r l

.g t _ O. e CEA DESIGN .0 I i h n 1 i 1+ 1 i l

... - - -. ~ -.. l e 3 at j . r SPIDER HUB i I. d i kj l i S i Od 5 v i l ~ ~ \\_/ / C l ( ) i d d M B4C v V, y 3D V AG-IN-CD g SLUG 7 4 J 8" r OUTER FINGER Y. l r l C O N END CAP i. CENTER SPACER FINGER' E ( uist nuxEr. Figure R CO. me'c P Control Element Assembly (CEA) 3.6-6 Atomic Power Station [. ( l .... ~ ~.. _..,.

j I

SUMMARY

OF CEA CONFIGURATION CYCLES 1-6 I 1 N.UNIBER OF CEAS J FULL STRENGTH 69 REDUCED STRENGTH TWO (2) 84C FINGERS 4 i ONE (1) 83C FINGERS 4 ) l TOTAL 77 4 1 'i i ? ? i l .t I- -..~

i + l i NEW CEA DESIGN L I i PROPOSED BY CE IN 1981 i l REPLACEMENT FOR LEAD GROUP CEAS FOR CYCLE 7 l DESIGN INCORPORATED FEATURE TO EXTEND LIFETIME OF CEA Substituted Ag-In-Cd for 84C in Lower 8 inches Of Center Finger Center Finger Identical To Outer Finger i i ) 4 ? ( i s i

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SUMMARY

OF CEA HISTORY THROUGH CYCLE 9 NUMBER OF CEAS IN REACTOR UI 1 ) i' i CYCLEIS) I 7 _3_ 1 l ORIGINAL DESIGN 77 ) 73) 73 68 2 i REPLACEMENT CEAS PURCHASED - 8 0 5 NEW DESIGN CEAS 0 8 8 13 TOTAL 77(2) g3 g3 g3 s [ i i (1). EXCLUDES PART LENGTH CEAS .(2); INCLUDES ElGHT (8) REDUCED STRENGTH CEAS (3) INCLUDES FOUR (4) REDUCED STRENGTH CEAS (2 B4C FINGERS) i

s s-aa.nu 1 n. ~a-.+- -a. . -.. ~.. >-.--e -" ~ <e-i.e. s m.ma -b, g 4 4 i P l r e i t t CEA MEASUREMENTS i I h t i t 1 . i C r f f/ . s.

e. e I i CEA MEASUREMENT HISTORY AT MAINE YANKEE I i 4 MEASUREMENT NUMBER OUTAGE ... TECHNIQUE. OF CEAn i EOC2 l ~3/77 Batelle Columbus Hot Cell 1 t EOC4 ~1/80 Single Frequency Eddy Current 6 EOC5 t ~ 5/81 Differential Transducer 19 (with Eddy Current) EOC6 + ~1/83 Multi Frequency Eddy Current 79 i EOC6 ~ Late 84 Battelle-Columbus Hot Cell 1 1 EOC8 ~8/85 Eddy Current (Encircling Coll) 61 Profiling ECT Profiling Colls u

1 c. i, [ MAINE YANKEE CEA CENTER FINGER EOC 8 WEASURED STRA!N j 28 t AVERACE = 0.47 26 SIGMA = 0.19 j-24 j>7 22 20 m 18 b O' 16 e - g. i 14 w ^ 5 ~ l 3, a 10 p E o ' I, 8 5 s 4 O.0-0. 2 0.2-0. 4 0.4-0. 6 3 -0.S 0.8-1. 0 1.0- 1. 0 STRAIN (X) l L t i-i

SUMMARY

OF CEA STRAIN RATES FOR CENTER FINGER BASED ON MEASUREMENT PERFORMED THROUGH EOC 8 i CE RECOMMENDED RATE: 0.19%/ CYCLE l MY ANALYSIS: I BASED ON FlVE PAlRS OF DATA POINTS FOR EOC 5,6, & 8 MEASUREMENTS RESULTS e l AVERAGE RATE 0.10%/ CYCLE STANDARD DEVIATION 0.06%/ CYCLE MAXIMUM RATE

  • 0.20%/ CYCLE RECOMMENDED VALUE TO PROJECT REPLACEMENT REQUIREMENTS:

O.20%/ CYCLE Small deviations (approximately 5%) from this rate is allowed if projections are I over several cycles.

  • Rate corresponding to a CEA in the lead group

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-a w --.,w----=A 4 -u-how a ..a,4A 4 a om; I h e j t 4 e 'i i t 1 CEA REPLACEMENT PROGRAM k I t D i i 1 k 1 h - [ 9/ - o

.r -l t 1 METHODOLOGY USED TO DETERMINE REMAINING LIFETIME i i Determine Reinsertion Criteria (Umit Rate / Cycle) 1 . Strain 1.2. 0.2 = 1.0% Wear 14.4 2.0 = 12.4% Project Measured EOC 8 Strain and Wear into Future Cycles i X,i, u = X, + (N 9) x Rate oy Discharge Prior to Cycle N If Reinsertion Criteria Exceeded' CEAs Replaced Each Cycle is A " Cut Set" of Those Replaced for Strain and Wear 't t L l l' p i l

t TOTAL ORIGINAL CEA's REPLACED BOC 10 VERSUS CYCLE OF OPERAT1CN 60 i t 50 - i 5 "O ~ m t U .30 . s-2o N. io l l 9 o L to it i: CYCLE OF OPERATION PREDICTED IN 1986 E ACTUAL REPLACEMENT I t l l l l' l v \\ c3 .4 s --..-,....---n- ~,.. _.,. - - - _. --,-~~~,-.-,,+_-.----.,n

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SUMMARY

OF CEA HISTORY i l-NUMBER OF CEAS IN REACTOR 0) e i i C.YCLE(S) 1 g., 7 ,,,g,_, ,,,g_, 10,, 11 ._12. t l. L ORIGINAL DESIGN 77(') 73(3) 73 68-53 38 23 l REPLACEMENT CEAS PURCHASED - 8 0 5 15 15 15 NEW DESIGN CEAS ' 0 8 8 13 28 43 5 TOTAL-77 ) 81 81 81-81 81 81 8 i e t l (1) EXCLUDES PART LENGTH CEAS (2) INCLUDES ElGHT (8) REDUCED STRENGTH CEAS (3) INCLUDES FOUR (4) REDUCED STRENGTH CEAS (2 B4C FINGERS) L i ...-........,_._...--._._...-_.,,,..._,.,_.l.,

a a..- e ..s-w.-s.s.s. -ww-4-a a w e a+. - -s-a a +1 m a.~aa.Aa-~.. > -.s- --s.aa-. --Lsaa-_ sr.r.g s .m.,a

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<.e- + i ' 4 l-1 I ? ? 2 DISCOVERY OF FAILED CEA 4 ) i L k I E f L ( t - A s t

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o r l SEQUENCE OF EVENTS STUCK CEA #79* o CEA Exercised 1 30 Inches After CEAs Latched i o Cold CEA Exercises initiated a CEDM 53 Exercised From Fully inserted To Fully Withdrawn o CEDM 53 Inserted Does Not Drive Beyond 38 Steps (28 inches from Bottom o CEA Position Indication Trouble Shooted Indication Verifled o CEDM 53 Coll Currents Measured While Operating to Diagnose Problem Results inconclusive o Decision Made To Remove Head To Diagnose Problem o Head Removal o TV Camera Lowered into Dupl CEA Shroud o Verifled CEAs Latched - o No Visible Obstruction Observed o CEAs Unlatched o TV Camera Lowered into Dual CEA Shroud o Verified CEA 79 Position Unchanged o Vertfled Twin CEA Bottomed Out o Upper Guide Structure (UGS) Raised Approximately One-Foot Verifled CEA #79 Free of UGS o UGS Removed CEA #79 Position Unchanged o Applied Uplift Force on CEA #79 While Fdel Assembly R011 Resident in Core CEA. #79 Removed from R011. o Visual Inspection of CEA #79 Identified Four (4) Inch Axlal Crack and Remainder of Finger Components (Upper Spacer Diso and Spring) o B4C Pellets Missing CEA 79 is one of two CEAs Operated by Control Element Drive Mechanism CEDM 53 i

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SUMMARY

OF COMPARISONS- ~ 1 I 4 PREDICTED TO MEASURED STRAIN f-t 5 l j eo '[ i <i 4 ) ' '3). .s-i 32 rif 'T i l 'j t t 1 .o l { 1 6 -{ r a- - t P s; 'l q I I r

y sp~ c.; +' M,;) MAlNE YANKEE CEA CEtCER F:NGER sy. ECC 11 DISCH ARGED AREDICTED STDAING ,,)h. 19 D L. AVERAGE'= 1.01 SIGMA = 0.11 16 l t 15 14 G 13 -= -{ 10 11f o j .h. 10 ~5 S{ j .h 7 ~ '2 j -0 AVERAGE = 0.83 l la ME. (TRED - SIG% = 0.21 17 - I

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.16 ^' 39-l- g3 ]. j ^ ! g4 l 40 33 I ~P [9 g 10 U 11 j h to l !5-8 8 4- . MAX.. STRAIN 7 1.23 l I 6 S-4 3 - i ' O.1 -0.3 0.3-0.5 0.5-0. 7 - 0.7-0.9 - 0.9 - 1.1 1 ' 1 - 1,3 ' 1.3-1.5 I STRMN. d i U

m ^" ,{. ' ( y f - ? + 1 f f. COMPARISON OF PREDICTED l e TO m 1 L MEASURED STRAIN e t a-j I' RATE USED TO PREDICT F*1P'.ACEMENTS,_0.20%/ CYCLE . i. o Bounded Average Measure Rate (0.16%/ Cycle)- Did Eg1 Bound Maximum Rate (0.26%/ Cycle) o 1 1 Resulted in. Approximately'Two (2) CEAs Exceeding The Discharge-A o Limit of 1.20% Strain 1 3 CEA# Cvele Discharae 8 11 37 10

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Enclosure = ; g + 1 AGENDA-1 - NRC/ MAINE YANKEE MEETING j June 25,1990 ~ a 1 ^ W Introduction + , I, \\

===. Background=== l \\ Surveillance Program. .I Replacement Program ) p', H ) Discovery of Failed CEA Eddy Current Exam Results Visual Examination Results H Fuel Inspection i v, y:.'i e (.- 9< Cycle 12 Operations. o r } L' ', ' r Conclusion I t,, I.ii > 1 J. ': 3,F. l^ 1 1 2'i ________Li,_____..

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k'i ; "" c e; s ] fD-! .p c i INITIAL PLAN 1 m iv' il i CEA'S l Examination ~ u Replacement ) 'l !{ FUEL e Examination-J 1 i Reconstitution Removal of CEA Parts 1

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t ? s t f-in CEA INSPECTION c L 4 .s D ~ 1 E b' Design Description l New Cycle 12 2'o Reference Original Cycle 12 Now Discharged. 15 Reference ' Discharged Cycle 11 15 - Reference Discharged Oycle 10 u 4 ? 16-Reference ' Discharged Cycle 8-l- p1 L . Evaluated all fingers in each F ?6 't. ii .l! I 1 I); t $) /

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CYCLE 12 CEA CONFIGURATION 1 l- - Number Design Cycles 8 New 5 5 New 3 l 15 New 2 . 15: Now: 1 ~ 37. New 0 1 Reference - 0 ~ +. s b [l 'i .I i sww a 4 r--

j '.;',, ;- a i., .n im.. p g' ' ^j ' p i f 4 'I' \\. ~ :L L BASIS FOR CYCLE 12 OPERATION U s: ? s ? ^ - New Design CEA's Highest exposure - 5 cycles .i Demonstrated 11 cycles j 1 Examination of CEA's Reference Design CEA's .1 CEA'- unused i Demonstrated 8 cycles j 7 Non-trippable group. CEA Parts Removed from Core t i ~ s J 8 0 4 .,~ i

N 6 9)+ t t o 4 x m -1 gun,,# 4 4 ~. I it l ei q;; .i. ' j i': lll 4 T. \\ FUTURE PLANS

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. t ,u d Hot Cell Examination. Future Inspection Plans -i fa Continued Ants; sis .f' i j J a -t~ , i.,' ! j s i n l? I I l.; t 1 k ie i i y r )b 7 1

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. +." LOWER Elm 0F CEA CENTER FINGER j s x u N \\ .N =J l<! ,/ / /s .s u ,/ s' ,/ / s .q N gg -l s s g / N -j s ,/ s \\ /' /N [/ N N /// i ~ V// / / i /./ / i / 6, / N .i j,,/ .f u. s i f.e l j, ' , s s /,! b'}h e f M,,. \\! U-r4\\,\\x\\\\\\ [ t.- N i // i / / 4 l L(,

p St3 MARY OF FAILED MAINE' YANKEE CEAS

  • .c AT EOC-11 (CEnitR FINGERS ONLY)'

MISSING CEA ~ CYCLES Els CAP STRAIN ML IN CORE EEER YES HD 111 79 9 3415 X 154 39 11 4492 X !GI 40 11 4492 X iG4 06 11 .4492 X ISI 64 11-4492' X 0.63 90 7 2732 X. 0.43 30 11 4492 X 1.05 l 65 11 .4492 -X 1.05 18 11 4492 X 0.74 )

+ u-l . 6.- i SUMARY OF OBSERVATIONS ON CENTER FINrJRS l WITH EW PLUG CIRCINERENTIAL CRACKS ~ EXPOSURE i HISTORY. RESIDENT FUEL ASSEM LYs- ~ CEA CYCLES (EFPD)- CYCLE-11 . CYCLE-10 INSPECTION RESULTS ~ 79 9 (3415) P852 M419-3.7" LONG AXIAL CRACK, NO PELLETS i IN FINGER, EW CAP, SPACERS A M i 32-33 B C PELLETS RECOVERED-4 39 11 (4492) P870 P432 4.5" LONG AXIAL CRACK, PROBE .l CONTACTS PELLETS 1" FROM BOTTOM 0F FINGER, EW CAP AW SPACER RECOVERED. 06 11 (4492) P871 P008 6.5" AXIAL CRACK Am 2500 CIRCLMFERENTIAL CRACK IN WELD REGION 40 11 (4492) N867 N413 4" LONG AXIAL CRACK, PROBE ) CONTACTS PELLETS 11" FROM BOTTOM OF FINGER, EW CAP A W SPACER NOT FOUW l u ~

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~ - _ kfh s ,g 4, a' Schematic of the Bottom'of a CEA Center 1~'- - Finger Showing the Axial 1.ocation of Cracks -l Maine Yankee. 7.o ; s.: Calvert Cliffs 2

  • EOC EOC-11 l

l ~ 4.8 t r r.; S t Pellet g 4.4 r j 4.0 .] '. 0 3.6 Set Pellet I ..M y;1 1-W C.' i 3.2 d l 8: '*e e. r 8.. 2.8 - J. S C 8ellet.- T ,e: 4 . x. , 3.4 1) C,4, $l ' 2.0l- 'IA AE gg C .., A CE u<,I, S t Pellet 'l ' - 1.6 g I I l l 1.2 $7Alst(11 Sit!L 0.8 Specta en se en dm 2.e t ) n no n as i \\ l l I j m -- l'

m. s ~ ' < '~. m'~ s 7 w ~ ~ P.. INCONEL-625 CEA CLAD TUBING FAILURE MODES ~ ~ ~ 01 INITIAL PREMISE WAS T01:l"lT TOTAL STRAIN OF CEA CLAD r ,s l

FAILURE ECHANISMS ASSINED TO BE BRITTLE FRACTURE

~ l -(1% E CHANICAL STRAIN LIMIT) OPPD DATA UP TO-APPROX. 3000 EFPD USED TO DEVELOP j L STRAIN LIMIT MODEL d 1 i o NO CRACKS-SEEN AT:OPPD q o PREMISE VALID FOR E CHANICAL STRAIN LIMIT j o UNEXPECTED FAILURES OBSERVED Ill 1986-1987 AT CC-2 ~ FAILURES ATTRIBUTED TO IASCC ] 1 EARLIEST FAILURE OBSERVED AFTER APPROX. 2900 ErW EXPOSURE 1 MATERIALS SUSCEPTIBILITYtTO IASCC EVALUATED 1 l o MATERIAL MORE SUSCEPTIBLE IF HIGH. YIELD STRENGTH I Als HI-SIL CONTENT (ALL1WIDlIN SPEC.) a o IASCCiSUSCEPTIBILITY INCREASES WITH FAST NEUTRON FLUENCE y i . =. m.

= M.Y.~CEA FAILDR3 --POSIULATED SCENARIO ~ ^ - 1 o SOMETIE DURING CYCLE 9, '10, LOR 11,: AXIAL THRU WALL CRACKING OCURRED I i NEAR BOTTOM 0F CENTER CEA FINGER l 8 C SELLING PROVIDED STRESS / STRAIN l 4 IASCC CRACKING MECHANISM o AFTER SOE OPERATING TIE AXIAL CRACK PROPAGATED Am INITIATED CIRCIMFERENTIAL CRACKING IN LOWER EW PLUG WELD REGION STRESS PRODUCED 8Y: COOLDOWN STRESSES AM/0R 8 C/ WATER REACTION 4 PRODUCTS l l 0 CRACK PROP 0GATION IN EW CAP WEID REGION PROGRESSES UNTIL CAP FALLS l OFF 1 BRITTLE FRACTURE FROM C00LDO W t IASCC OR OTHER:CHEMISTRYLIWUCED CRACKING ECNANISM l i ..J

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o - y, ~ i WORK IN PROGRESS OR PLAMED ~ o CC CEA #3 OPERATED FOR 1 FULL CYCLE WITH AN AXIAL CRACK b (ECT-INSPECTION DONE) 'j 4, VISUAL EXAMINATION REQUESTED BY THE RRG PERFORED ON 6/23/90-0- NO CIRCIMFERENTIAL CRACK o NO.SIGNIFICANT PROPAGATION OF OtB AXIAL CRACK I 1 CC CEA #3 WILL BE SUBSTITUTED FOR A CEA SCHEDULED TO BE SHIPPED-TO A HOT CELL-BY LATE JULY, 1990 AS PART 0F A BG&E/CE/EPRI PROGRAM I o HOT CELL EXAMINATION OF MY CEAS BEING EVALUATED. BEST SAW LES ARE CEA i i

  1. 6 A W AVAILABLE EW CAPS FROM CEA #79 AW #39 l

SCOPE HIGH MAGNIFICATION VISUALS-j FRACTURE CAUSE DETERMINATION i o ETALL0 GRAPHIC - o SEM FRACTURE: SURFACE OXIDE THICKhESS o DATE CRACKS A W CRACKING SEQUENCE I q i = _., _ ~. -.~m. - .i

= ~ ~ '~ ,J wn ~ ~ mr O my ' [t ~I o M.Y. EOC-11 ECT INSPECTION 1 I OUTER FINGERS NO INCIPIENTLOR THRU CRACKS L(~4500 EFPD)' l CENTER FINGERS HAVE 5LIIBICATIONS OF THRU CRACKS HEAR TIP AT STRAINS LESS'THAN 1.05%; L i r l 0 H.Y. EOC-11 VISUAL. EXAMINATION l CENTER FINGER i ~. I o EVIDENCE 0F-AXIAL CRACK AT ~ 2730 EFPD 1 o EVIDENCE OF: PROPAGATION ~OF AXIAL CRACKS l l AT GREATER THAN ~3200 EFPD l o EVIDENCE OF DIFFERENT TILES OF FAILURES ~ i 0F BOTT(M EIS CAPS -.2- - l.s .m. _,_.,.4.. ,,__,..;_ _ _.,...___ L .n s

,x ~ 1 1 SWMARY (CONTINUED) ~ o IASCC OF INCONEL-625 CEA CLAD CAN OCCUR AFTER EXPOSURE OF ~3000 EFPD l 8 C SWELLING RESULTS IN AXIAL THRU WALL CRACK ~ j 4 ?INITIALIAKIAL CRACK PROPAGATES TO LOWER Els: PLUG q CIRCtMFERENTIAL' CRACK PROPAGATION BEGINS, MOST LIKELY ON C00LDOW 'I o AFTER INITIAL FAILURE OF CEA CLAD, COOLANT WATER REACTS WITH B C i 4 PELLETS RATE OF REACTION INEGIOW l LITHIIM AVAILABLE FROM B-10 FISSION' COUIE CHANGE ~ LOCAL CHEMISTRY WITHIN CEA CLAD AT TIP a a l ~ i f i u.~. .a...-.-~.

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~,. -l ~ F CEA~EXPoa g MIsF N --14x14 OLD DESIGN v. i MILESTONE EFPD CW9 BITS o HIGHEST OPPD DUTY E0C-9 2988 BASIS'FOR K CHANICAL i STRAIN ~ LIMIT o EXPOSURE'0F EARLIEST OBSERVED 2890 ATTRIBUTED TO IASCC -o AXIAL CENTER FINGER CRACK i CC-2, E0C-7 i ) '~ o MAINE YA KEE LAST ECT 3229 NO CRACKS OBSERVED INSPECTION E0C-8 i I i I o MAINE YA KEE FAILED EIS .3415 CEA #79 l CAP OBSERVATION EOC-11 l CEA #39, 40 Als 6 I 4492-o MAINE YAKEE LOWEST 2732 CEA #90 h . EXPOSURE AXIAL CRACK' I 1 i _..x__

';.a y_; ...... ~.... - -. -........ i '1 "I 3~, Enclosure.

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') 1 MAINE YANKEE E0C-11 CEA INSPECTION RESULTS u i o-115 CEA'S INSPECTED, ALL FINGERS, FULL LENGTH - 43 NEW DESIGN ALL FINGERS WITH AG-IN-CD IN THE "IP -- 68 OLD DESIGN- , > CENTER. FINGER WITH.B C'TO-THE TIP. 4 OUTER' FINGERS WITH AG-IN-CD IN THE TIP I i jf

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'A 8- 's i MAINE YANKEE E0C-11 CEA INSPECTION RESULTS O' 43 NEW DESIGN CEA'S l NO INDICATION:0F CRACKS NO INDICATION OF SWELLING (I.E.,. NO STRAIN) 24 FINGERS OF THE 215 FINGERS INSPECTED HAVE SOME MINOR FRETTING WEAR, 1 18 FINGERS HAVE INDICATIONS CLASSIFIED AS GEOMETRY CHANGES DUE TO SMALL OVALITIES?0R DENTS-BUT WITH N0 WALL -LOSS i NO.OTHER INDICATIONS q H L THE' CALIBRATION STANDARD S 90 DEGREE. 3 e ' CIRCUMFERENTIAL' EXTENT-WEAR SCARS WERE. i USED TO DETERMINE FRETTING WEAR DEPTH THEREFORE ARE CONSIDERED ' CONSERVATIVE \\; .1 l i

t MAINE YANKEE E0C-11 CEA INSPECTION RESULTS 'o 72 OLD DESIGN CEA'S: FINGERS WITH-B C TO THE TIP 4 -STRAINS?FROM 0.2% TO 1.27%. A TOTAL 0F 3. MISSING N0SE CAPS AND 1" NOSE CAP WITH A CIRCtMFERENTIAL CRACK IN THE WELD. ALL 4"0F THESE FINGERS HAVE AXIAL CRACKS VERY-MINOR WEAR ON SOME FINGERS A TOTAL OF.26 INDICATIONS, EXCLUDING THE 4 FINGERS MENTIONED AB0VE' 1 l l P

4,;+, Q^J.l 1JA i q t[ ~, ,L MAINE YANKEE E00-11 I T CEA INSPECTION RESULTS t ,i i %1I l0F THE TOTAL 0Ft26 INDICATIONS \\ -i o 5 ARE' AXIAL THRU-WALL CRACK INDICATIONS: l I t ALL ARE LOCATED IN THE RANGE l FROM 1.2 TO 2.0' INCHES FROM u .THE TIP:OF THE NOSE CAP 1 FROM 1/4 TO 1/2 P C3 AXIAL LENGTH e ALL ARE " TEXTBOOK" CRACK INDICATIONS 1; o 21 ARE-INDICATIONS FROM UNKNOWN SOURCES 1 ALL ARE LOCATED AT 0.5 INCH FROM THE TIP OF THE-NOSE ~ CAP y NO CRACKS WERE FOUND DURING A VISUAL INSPECTION i w .t f -f j!. 'j C

e MAINE YANKEE E00-11 CEA INSPECTION RERULTS o-72 OLD DESIGN CEA'S i FINGERS WITH AG-IN-CD NO CRACK INDICATIONS p MULTIPLE MINOR FRETTING WEAR SCARS STRAINS RANGING FROM 0.1% TO 0.3% ALL STRAINS GREATER THAN 0.1%.ARE 21 INCHES OR NIGNER ON THE FINGER NO OTHER INDICATIONS FOUND l -o M t. b =

Enclosure FUEL INSPECTIONS / COMPONENT RETRIEVAL 1. QUALIFICATION OF NEW FUEL ASSEMBLY RO11 FOR SERVICE 11. INSPECTION OF IRRADIATED FUEL FOR CEA PARTS 111. RETRIEVAL OF CEA PARTS IV. CEA FINGER COMPONENT ACCOUNTABILITY l u

____.__.__.______._.._.__...._...y .c

1. QUALIFICATION OF NEW FUEL l

ASSEMBLY RO11 FOR SERVICE I CONSEQUENCES OF FAILED CEA I CENTER GUIDE TUBE OBSTRUCTION CENTER GUIDE TUBE /CEA INTERACTION CEA PARTS RECOVERY PARTS REMOVED BY PUSHING UP INTO THE CENTER GUIDE TUBE WITH RIGID NYLON TUBE i DEBRIS CONSISTED OF 31 WHOLE AND APPROXIMATELY 2 BROKEN BORON CARBIDE PELLETS ASSEMBLY INSPECTION PRELIMINARY INSPECTION DETAILED VISUAL INSPECTION USING CE AND YANKEE CRITERIA 1 f f i l' l i

i ~0 ] ) RESULTS OF QUALIFICATION INSPECTIONS l j i CENTER GUIDE TUBE FREE & CLEAR OF i ALL OBSTRUCTIONS l SUPERFICIAL. EVIDENCE OF CEA/ GUIDE TUBE INTERACTION NO VISIBLE OR MEASURABLE DEFORMATION l OF ASSEMBLY COMPONENTS l NO ADVERSE IMPACT ON FUEL ASSEMBLY MECHANICAL INTEGRITY ASSEMBLY RO11 ACCEPTABLE FOR OPERATION j i l 1 l ..r h l l l l I . ~. d

= II. INSPECTION OF IRRADIATED FUEL FOR CEA PARTS IDENTIFICATION OF HOST FUEL ASSEMBLIES SINCE EOC8 ALL FAILED CEAs DETERMINED TO BE INTACT AT EOC8 BY EC AND PROFILOMETRY INSPECTION FOR MISSING CEA PARTS ASSEMBLIES P870 AND P852 CONTAINED CENTER GUIDE TUBE OBSTRUCTIONS FROM CEAs #39 AND #79 RESPECTIVELY l ALL HOST ASSEMBLIES FOR CEA # 40 WERE CLEAR BACK TO INITIAL CORE l l l i E ~.

[L. .e RESULTS OF IRRADIATED FUEL INSPECTIONS MISSING PARTS FROM CEAs #39 AND #79 LOCATED IN ASSEMBLIES TARGETED FOR o ~ CYCLE 12 OPERATION PARTS FROM CEA #40 NOT LOCATED, HOWEVER, HIGH DEGREE OF CONFIDENCE NOT IN CORE 12 L NEVER RESIDED IN CORE 12 FUEL DISCHARGED WITH FUEL EOC 11 i NOT HANDLED DURING CORE 11/12 COMPONENT SHUFFLING 1 1 l L i l l 1: 1

i c t Ill. RETRIEVAL OF CEA PARTS FROM IRRADIATED FUEL DESCRIPTION OF TOOLING . TOOLING SET-UP/ OPERATION i RETRIEVED CEA PARTS e I k [ f .i ) i 7 t ( i 1 (. I'

( ! e I ~ .v s \\ / .k /a 3 CATCH BASrJT i 1/2 INCH RIGID NYLON TUBE ~< r ~ ~ Ill f h01nfinprin'05 ( irl ueillfr [ 1 INCH ALUMINUM CONDUIT (mFvkf--Y%(( ) H ,~ CATCH BASKET / ASSEMBLY INTERFACE DETAILS ~ ..r"# e i ,I i l ..ep.. ili!Ii( ! v U@I .J. l L i 12 - PEDESTAL p 4 i. j (; t l ' l e L

] RETRIEVED CEA PARTS FROM IRRADIATED FUEL ASSEMBLY P852 FIVE BORON-CARBIDE-PELLETS SS SPACER NOSE CAP ASSEMBLY P870 SS SPACER NOSE CAP l t i e h t i _ _. _ -. -., -. ~. - _,.

1 o e, o i CONCLUSIONS s I SUCCESSFULLY RETRIEVED ALL CEA PARTS FROM THE CENTER GUIDE TUBES OF TWO ( ASSEMBLIES TARGETED FOR CYCLE 12 OPER ATION-POSITIVE INDICATION OF CLEAR GUIDE TUBE THROUGH FULL-LENGTH NYLON TUBE PROBE ] HIGH PRESSURE BACK OUT FLUSH TO REMOVE. CRUD AND SMALL DEBRIS IF PRESENT CLEAN. BILL OF HEALTH FOR ASSEMBLIES-i P852 'AND P870 e l

  • j' s

I t

l 1 IV. CEA FINGER COMPONENT ACCOUNTABILITY LOCATION METHOD l CEA - FINGER PERISCOPE, CEA PROBE l TOOL FUEL - GUIDE TUBES FUEL PROBE TOOL - TOP OF FUEL TV CAMERA SPENT FUEL POOL - TOP OF FUEL TV CAMERA - EMPTY RACK LOCATIONS VISUAL - UPENDER AREA TV CAMERA s REFUELING CAVITY - CAVITY FLOOR TV CAMERA, VACUUMING VESSEL - LOWER HEAD TV CAMERA, VACUUMING - CORE SUPPORT PLATE TV CAMERA, VACUUMING i 5 L l b i

VERIFICATION OF ASSEMBLY S/N AND COMPONENTS VIDEO VERIFICATION PERFORMED i ? FOLLOWING ORIGINAL COMPONENT l TRANSFERS IN SFP FOLLOWING ORlt3lNAL CORE LOADING IN CAVITY FOLLOWING FINAL CORE LOA']ING IN CAVITY NO MISSING CEA PARTS OBSERVED f-L i l l, <, 1

w .ew s,&--A w4,, ss-Ae O --2------vs- -em 3-A a de---a--me-AA4-s- <-ua-- a A-4a om-m,-n._ A + .n aL j ... e s I CEA FINGER COMEONENT ACCOUNTABILITY RESULTS LOCATION RESULTS END . LOWER PELLETS UPPER SPRING CAP DISK DISK CEA 0 0 0-270 3 3 FUEL 2 2 38 0 0 SFP O O O O O CAVITY 0 0 0 0 0 VESSEL 0 0 0 0 0 MISSING 1 1 100-380 0 0 t n s ? t P 2

y x. CONCLUSIONS .l HIGH DEGREE OF CONFIDENCE THAT NO ASSEMBLY WITH LOOSE CEA PARTS WAS RETURNED TO CORE UNLIKELY THAT A SIGNIFICANT NUMBER OF PELLETS ARE ON FLOOR OF SFP OR CAVITY ,j REMAINDER OF PELLET STACK (ABOUT 100 INCHES) FROM CEA #79 UNACCOUNTED END CAP AND LOWER SPACER FROM CEA e

  1. 40 UNACCOUNTED UNKNOWN INVENTORY OF PARTS REMAIN IN CEAs 39 AND 40 1

i l ) l I

5 s DISTRIBllTION: 59NietIBM!i. NRC PDR Local PDR F. Miraglia J. Partlow .PD1-3 R/F 'Y. Herses E. Leeds OGC E. Jordan J. Johnson, Region I R. Freudenberger L. Phillips A.~ Young D. Fieno W. Koo ACRS(10) M. Rushbrook J. Caldwell M. Snodderly 1 S. Magruder M. Huang T. Litton J. Larkins-l M. Campbell J. Norris-T; Attard i R. Winters,-' Region.I i G. Vissing S. Long S.H. Wu. j ' Steven Long i ll i t [ I t e t f ,}}

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