ML19323F304

Updated LER 80-002/01T-2:on 800227,increasing primary-to- Secondary Leak in Steam Generator A.Caused by Leaking Tube in R18C37 Position.Eddy Current Testing Revealed Defective Tubes in Both Generators.Tubes Explosively Plugged

ML19323F304
Person / Time
Site:	Point Beach
Issue date:	05/16/1980
From:	Fay C WISCONSIN ELECTRIC POWER CO.
To:	NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION III)
Shared Package
ML19323F293	List: ML19323F292 ML19323F304
References
LER-80-002-01T, LER-80-2-1T, NUDOCS 8005280746
Download: ML19323F304 (7)

Text

CRC FORM 364 n.m Mi N UPDATED REPORT - PPEVIOUS REPORT

• StmMITTED MARCH U. S. NUCLE 12, 980 AR &C1Out A ATORY NYL

_ LIGLNSut cVtN i HLPOR )

CONTROL SLOCK: l i

l l l l l

.h l IPLEASE PRINT OR TYPE ALL REOUf REO INFORMATIONI

[T[T]8 l9 N l ILICENSE 8 l P lE CCOE B l !! l 2 l@l 0 l 0 l- l 0LICENSE 14 5%

l 0 lNUMdEH 0 l 0 l 0 l - l 0JSl 026l@[4 l 1 l1 (1 l 1l@l LIG4M4 TYPE 40 l

%7 CA T 58 l@

CON'T f6T'l 3E I L64 @l 061 l 5 l010 l 0l 310 l 1 Q[ 0 l2 l 2 l7 l 3 l0 @l 0 l 5 l 1; 6 l 8 l 0 l@

I 8 6d OOCKET NUMdER 63 EVENT QATE 74 JS REPORT OATE 80 EVENT DESCRIPTION AND PROBAOLE CONSEQUENCES h E I During normal oceration, indication of an increasing primary-to- l g [ secondary leak in the "A" SG was noted on 02-27-80. The decision was l 101 1 l made to shut the unit down at 2 340 hours0.00394 days <br />0.0944 hours <br />5.621693e-4 weeks <br />1.2937e-4 months <br /> on 02-27-80 and the unit was l 10 , s j [ o f f line at 0225 hours0.0026 days <br />0.0625 hours <br />3.720238e-4 weeks <br />8.56125e-5 months <br /> on 02-28-80. Chemistry results of a sample l Io is 1 I taken at 0010 hours1.157407e-4 days <br />0.00278 hours <br />1.653439e-5 weeks <br />3.805e-6 months <br /> on 02-28-80 quantified a primary-to-secondary [

lOlill leak rate of 1,420 callons per day. This event is reportable per i i y1 T.S. 15.6. 9. 2. A. 3 and is similar to previous LER's . 1

. 8 9 SYSTEM

'O CAL'SE CAUSS COMP.

, COOE CODE SU8 CODE VALVE CCMPONENT COOE SUSCOOE SUSCOCE LO.uj .

3 s I C i sto l@ LE_J@

9 in l o l@ .I laa i T l E I x i C l aid l@ IF l@ LZ_J 12 i3 20

, SEQUE NTI AL OCCUARENCE REPORT REViSICN Lgm O EVENTvtAR REPORT NO. CCOE TYPE NO.

@,ag'*af l 810 l

_ 21 22 l-l 22 l010l2l 24 26 y l O ll l lT l l-l [2_j 27 28 TJ 23 31 22 A CTiON PUTURE EPPECT SHUTOOWN A TT ACHM E N T TAKEN ACTION ON PLANT METHCO N P 4 0-4 PAiuf COMP. COSPCNENT MOURS o SuaMiTTE D PC Au sV8. $UPPLIE A uANUPACTURER L2J@L.zJ@ lasa l@

22 2 lal@

a loI313121 se lYl@

u l YlO I.2N I@ lWili2iolg ,

4o 42 u 4, t CAUSE DESCRIPTION AND CORRECTIVE ACTIONS m lA crimary-to-secondarv leak tes t cerfor- ed on 03-01 00 revealed a l  ;

Iiii1lleakina tube in the "A" SG at cosition R18C37. Eddv current testina 1

,,,2, [ becan in both SG's on 03-03-80 and was completed on 03-09-80. One I y l decraded (411 defeet) tube was found in the "3" SG and six de factive l l ti,4 i I (>50%) tubes and 18 tubes with cluccable (409 to 49%) defects were founct

> s :.n ne "A" steam generator, so

'sTAN 4PCWER OTHER STATUS DIS O RY DISCOVERY OESCRiPTION I Is ] l E l@ l '019 l 9 l@l "M/A l l Al@l Operator observation l

'driviTy CCOTENT " **

u LtAsEO OP aELEAsE l1 l6 ] l G l @ Qigl 1.4 7 CuriesAuCUNTeP [ Air ACTiviTv ejector @ l LOCATION CP RELEASE @

l 3 8 3 iG If 44 8%

PERSONNEL EXPOSUAES to NuueEn TYPE O!3CRiPTICN i 7 l0l0l0l@l'l@lN/A '

i l

PE nsONy E't iNau'n'iES **

NUM.ER DESCRIPTION @

Lt J.S.J. l 0 l 010 l@l N/A ii 2 so I

LOSS TV'E CP 04 OAMAGE TO PACILITY Q DE SCDIP TION N,/

lil91lij @l N/A l 3 4 3 to

/ 00 l

PU8tiCITY 1 I1 SUE O OP CCRIP T:CN NRC USE CNLY I j

11L.J LY_J81 nowanana r. TV. and radio covorvra i

> a e i0 I I i i I I I I I I I I 'li C. W. Fay 6.

\ ,....p0 r -

NAME OF PREPARER PHONE:

414/277-2811  !,

_ u o un san 7tb6

. l l

l ATTACHMENT TO LICENSEE EVENT REPORT NO. 80-002/0lT-2 l l

Wisconsin Electric Power Company Point Beach Nuclear Plant Unit 2 Docket No. 50-301 Unit 2 was taken off line at 0225 hours0.0026 days <br />0.0625 hours <br />3.720238e-4 weeks <br />8.56125e-5 months <br /> on February 28, 1980 following confirmation of primary-to-secondary leakage in the "A" steam generator. The leak had begun as a slight indication about noon the previous day and gradually increased to 70 gallons per day (estimated) by 2200 hours0.0255 days <br />0.611 hours <br />0.00364 weeks <br />8.371e-4 months <br /> on February 23. The decision was made to shut down at 2340 hours0.0271 days <br />0.65 hours <br />0.00387 weeks <br />8.9037e-4 months <br /> upon a further large increase in the air ejector radiation monitor reading. A static head leak L check identified the leaking tube at position R18C37 and a subse-quent eddy current inspection placed the defect at eight to ten inches above tha tube end, i.e., 13 to 15 inches deep in the crevice of the tubesheet. The previously scheduled refueling outage steam generator eddy current inspection was performed o during the outage. The extent of the inspection was expanded during the outage as six tubes with greater than 50% through-wall  :

indications, in addition to the leaking tube, were discovered in  !

the "A" steam generator. Eighteen tubes with indications between

• 40 and 49% were also found. The "A" steam generator hot leg j program was first expanded by a 25 sample then to 100% as required by the Technical Specifications.

The 25 defective or degraded tubes in the "A" steam  !

generator were explosively plugged on March 10, 1980. The leaking tube was mechanically plugged on the inlet side. This tube has been pulled during the April 1980 refueling outage for further examination.

Eight tubes which cxhibited 39% defect indications were also explosively plugged as a conservative measure. Two tubes ,

R22C62 and R9C54, also with 39% defects, were plugged on the cold leg only. These tubes were mechanically plugged on the hot leg side during the April 1980 refueling outage.

An 800 psi hydrostatic test of the "B" steam generator ,

revealed no leaking tubes or plugs. Approximately 700 tubes in each of the hot and cold legs of the "B" steam generator were examined and one cold leg tube was found to have a 41% defect indication. The one 41% degraded tube in the "B" steam generator was explosively plugged on March 9, 1980.

Unit 2 was placed on line at 1802 hours0.0209 days <br />0.501 hours <br />0.00298 weeks <br />6.85661e-4 months <br /> on March 13, 1980.

The average radioactive release rate via the Unit 2 air ejector during this event has been calculated to be 0.051%

of the allowable annual release rate of 0.2 Curies per second.

This event is reportable per Technical Specification 15.6.9.2.A.3.

The approximate exposures recorded during the outage are as follows: (All exposure data are based on dosimeter information.)

Steam Generator Manway Work 1.8 Man Rem Visual Inspections '

O.8 Man Rem i

Eddy Current Inspections 14.7 Man Rem Tube Plugging 5.9 Man Rem Health Physics Coverage 3.4 Man Rem I

5 1

G l

i

s EDDY CURRE!!T RESULTS FOR PLUCCED TUBES STEAM CE'IERATOR " A" INLET l Tube  % De fect Location  !

R21C58 42 Top of tubesheet*

R10C59 39 Top of tubesheet R20C59 41 Top of tubesheet R21C59 39 Top of tubesheet R20C61 42 Top of tubesheet R20C63 51 Top of tubesheet R21C6 3 56 Top of tubesheet R10C64 42 Top of tubesheet ,

R21C64 46 Top of tubesheet R19C65 51 Top of tubesheet R18C68 39 Top of tubesheet R12C73 43 Top of tubesheet R34C73 43 First support plate RllC74 39 Top of tubesheet e, R07C21 39 Top of tubesheet

.s R13C19 40 Top of tubesheet R12C31 41 Top of tubesheec R13C34 43 Top of tubesheet R14C34 57 Top of tubesheet R14C35 42 Top of tubesheet R15C 35 44 Top of tubesheet .

R13C36 42 Top of tubesheet l R14 C36 39 Top of tubesheet .

R10C39 45 Top of tubesheet '

3 R13C41 56 Top of tubesheet R18C37 100 9" above tube end i R28C42 45 Top of tubesheet R20C4 3 39 Top of tubesheet R12C44 41 Top of tubesheet R20C4 7 39 Top of tubesheet R21C57 43 Top of tubesheet R22C57 42 Top of tubesheet O R10C58 52 Top of tubesheet STEAM GENERATOR "B" OUTLET R07C36 41 135 " above tubesheet

• The notation " top of tubesheet" refers to defect indications which have been separated from the tubesheet entry eddy current signal using multi-frequency .

techniques. The recent development of this technique, which was used for the j first time on Unit 2 during this inspection, permits much better discrimination i of low volume defect indications from the tubesheet signal. During previous  !

inspections, using only 400 KHZ eddy current signals, the majority of these top of tubesheet indications were referred to as either distorted tubesheet signals or less than 20% indications. In some cases they were not characterized as abnormal signals. In only two of the tubes, R20C47 a,nd R21C64, had previous tube defects at or near the tubesheet been consistently reported and quantified l Table 1 sumarizes the previous inspection reports of these tubes. j 1_

i

, i ED0Y CURRENT RESULTS FOR PLUGGED TUBES - STEAM GENERATOR "A" INLET In order to establish whether the remaining defects had been present in previous inspections, the 400 KHZ eddy current tapes for all previous tube inspections, dating from as carly as 1974, were reviewed and compared to the 400 KHZ signal alone from this 1980 inspection. The object of this comparison was to evaluate whether the 400 KHZ eddy current tubesheet entry signal was essentially un-changed from inspection to inspection. It was concluded from this comparison that the majority of tubesheet entry signals for those tubes having been pre-viously inspected, were unchanged from the 1980 400 KHZ signal. From this comparison it was concluded that the majority of these top of tubesheet defect indications have been present but undetectable in previous eddy current inspect-ions. Table 2 summarizes the results of this comparison, 1

l l

I l

9

• 1

TABLE 1 PREVIOUSLY REPORTED STEAM GENERATOR EDDY CU!! refit IriSPECTION RESULTS UNIT 2, "A" INLET 1980 1979 1978 1977 1976 1974 Pl.W - COL.

l 40 - TTS NI NI NI NI NI 13 19 39 - TTS NI NI NI NI NI 7 21

d 31 41 - ITS til -- DTS -- --

, i3 34 43 - TTS til -- DTS -- --

i4 34 57 - ITS N1 -- DTS --

i4 35 42 - TTS NI -- DTS --

i5 36 44 - ITS NI -- DTS DTS

'. J 36 42 - ITS NI N1 <20-TTS <20-TTS <20-TTS 4 ;4 3b 39 - TTS N1 -- DTS

10 39 45 - ITS -- NI NI --

56 - TTS DTS DTS i i3 41 NI N1 42 45 - ITS NI NI N1 <20-1/2"ATS <20-1/2"ATS

_t d 40 43 39 - TTS COPPER -- DTS <20-1/2"ATS 23-1/2"ATS 12 44 41 - TTS fil -- <20-TTS <20-TTS --

to 47 39 - TTS 30-1/ 2" ATS 31-1/2"ATS 30-1/2"ATS 31 -1/ 2"ATS 23-1/2"ATS 9 54 39 - TTS NI NI DTS <20-1/ 2" ATS <20-1/2"ATS 21 67 43 - TTS til -- <20-TIS <20-TTS - - -

t 67 42 - TTS til -- DTS N1 --

id 58 62 - TTS N1 -- DTS DTS 6d 42 - TTS NI NI <20-1/2"ATS <20-1/2"ATS <20-TTS il 10 59 39 - TTS N1 --

<20-l/2"ATS <20-1/ 2" ATS <20-1/2"ATS 40 69 41 - TTS NI -- <20-TTS <20-TTS <20-TTS cl 59 39 - ITS NI fil DTS DTS --

to 61 42 - TTS til -- DTS DTS --

22 62 39 - TTS N1 -- DTS DTS 63 51 - TTS NI -- DTS DTS 20 63 56 - TTS fil -- <20-TTS <20-TTS <20-TTS 21 64 42 - ITS NI DTS -- Ni 10 fil 21-TTS 22-TTS N1 el 64 46 - TTS 30-tis COPPER 19 65 51 - TTS fil -- DTS NI til Id 68 39 - Ils til N1 til NI N1 12 73 43 - ITS N1 til NI N1 fil 73 43 -#1 TSP til til NI NI Ni 34 39 - TTS til til

• NI NI NI 11 74 TTS = Top of Tubesheet TSP = Tube Support Plate NI = Not Inspected DTS = Distorted Tubesheet Signal ATS = Above Tubesheet -- = Inspected with No Signal Comment

TABLE 2 i

COMPARIS0N OF PREVIOUS EDDY CURRENT SIGNAL The following table presents the results of the visual comparison of previously recorded 400 KHZ tubesheet entry signals to the 1980 inspection 400 KHZ tube-sheet entry signal for the listed tubes from the "A" steam generator inlet.

Tubes R7C21, R13C19, R18C68, R12C73, R34C73 and RllC74 were not inspected prior to 19d0.

NI = Not inspected S = Signal same as 1980 R0W COLUMN 1979 1978 1977 1976 1974 12 31 NI SMALL ALMOST ALMOST SAME AS CHANGE NORMAL NORMAL 1976 13 34 NI S S S CHANGE 14 34 NI POSSIBLE S ALMOST SAME AS CHANGE NORMAL 1976 l 14 35 N1 POSSIBLE CHANGE S S S lb 36 NI SOME SAME AS S CHANGE CHANGE 1978 13 36 NI NI S S S 14 36 NI POSSIBLE SAME AS S S CHANGE 1978 10 39 POSSIBLE NI NI SAME AS CHANGED CHANGE 1979 13 41 NI NI CHANGED SAME AS SAME AS 1977 1977 28 42 NI NI NI S S

20 43 S S S S SMALL CHANGE 12 44 N1 POSSIBLE S S SMALL CHANGE CHANGE 20 47 S S S S S 9 54 NI NI SMALL SAME AS CHANGED l CHANGE 1 977 22 67 NI S S NI S 10 58 NI CHANGED SOME CHANGE SAME AS SAME AS T01978 1977 1977 21 58 NI NI S S S 10 59 NI CHANGE SAME AS SAME AS SAME AS 1978 1977 1977 20 59 NI S S S ,S 21 59 NI NI S S MALL CHANG 20 61 NI S S CHANGE S -

22 62 NI S S S S 20 63 NI POSSIBLE S S S CHANGE 21 63 NI POSSIBLE S S S CHANGE i 10 64 NI NI S CHANGE NI '

21 64 S S S CHANGE N1 19 65 NI S S NI NI l 21 57 NI S S S S

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