Text

Updated LER 80-002/01T-01:on 800311,during 800 Psi Secondary to Primary Hydrostatic Leak Test,Tubes R23C44 & R8C37 & Plug End R23C50 Found Leaking.Eddy Current Insp Performed.Tube Holes & Leaking Explosive Plugs Were Plug Welded
	ML19309F345
Person / Time
Site:	Point Beach
Issue date:	04/17/1980
From:	Fay C; WISCONSIN ELECTRIC POWER CO.
To:	; NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION III)
Shared Package
ML19309F341	List: ML19309F340; ML19309F345;
References
	LER-80-002-01T, LER-80-2-1T, NUDOCS 8004290306
	Download: ML19309F345 (9)
	v • d • e

NRC FORM 366 U. S. NUCLEAR REGULATORY COMMISSION

(7 77:

UPDATED REPORT - PREVIOUS REPORT DATED MARCH 25, 1980

. uutWdet tytN i HtVUM I B 0 04290 30s CONTROL BLOCK. l l l l l l 6

lh (PLE ASE PRINT OR TYPE ALL f!EQUIRED INFORMATION) l0 lij lWlIl P lB lHl 1 l@[ 010 l- l 0 l 0 l 0 l 0 l 0 l- l 0 l 0 25l@l 4 l1 l1 l1 l 1 l@l l lg 7 8 9 LICENSEE CODE 14 15 LICENSE NUMBER 26 LICENSE TYPE Jo 57 CA T $a CON'T 101il 57,RC,' l L @l 0 l 510 l 010 l 2 l 6 l 6 @l 0 l 3 l 1 l1 l 8 l0 l@l 0l 4 l 1l 7 l 8 l 0 l@

7 8 60 63 OOCKET NUMBER tW 69 EVENT DATE 14 75 REPORT DATE 80 EVENT DESCRIPTION AND PROBABLE CONSEQUENCES h Fo 121 pith the unit in cold shutdown for a reauired 60 effective full power dayl iOi3 isteam generator testing program, an 800 psi secondary-to-primary hydro- l

[ O [4 ] istatic leak test of the steam generators was performed on 3-11-80. No l

[ O 1 s i l leaks were identified in the " A" steam generator. Inspection of the "B"l 10 l6 l l steam generator revealed one tube (R23C44) leaking approximately 3 drops /l 10171Imin., one tube (RSC37) that appeared wet and one wet plug end (R23C50). l l O is i !This event is reportable per T. S. 15. 6. 9. 2. A. 3 and similar to others . l 7 8 9 80

C$o'E '#'c'I C0 Sv8C05E COvPONENT COoe SueSEoE SEoE 10191 7 8 l Cl Bl@ W@ l D l@ l HlT lE lX l C l H l@ lF l@ [_XJ 9 10 11 12 13 18 1.) 20

,_ SEQUENTI AL OCCURRENCE REPORT REVISION LEq p0 E REPOR T NO CODE TYPE N O.

hag y l 8VENT 21 l 0l YEl-l 22 23 AR l010l21 24 16 l/l 27 l0 11 l 28 29 lT l Ju

[.--J 31 y

32 TA EN A Ti N GN PLANT VET HOURS S8 IT FOn e 8. SUPPL 1 R MANUFACTURER

[B 33 l@l342 l@ [_CJ@

35 lAl@

36 l 010 l O l 0 l 3/ 40

(_Y_j @

43 lYl@

42 W@ lWl1l2l0l@

43 44 47 CAUSE DESCRIPDON AND CCRRECTIVE ACTIONS h l i l o l lA previously scheduled eddy current insoection orogram was cerformed. 241 lililItubes in the "A" SG and 36 tubes in the "B" SG were exolosively clugaed I it 12i pxcept for the hot side of three tubes in the "B" SG which were pulled l

[ijal lfor examination. The 3 tube holes , along with 4 leaking explosive plugs l ii ;4i iwere weld plugged and hydrostatic test was performed af terwards. I 7 8 9 80 ST S "6 POWER OTHER STATUS DISCO RY DISCOVERY OESCRIPTION I i I 5' I [.G_J@' l 0 l 0 l 0 l@l N/A l lC l@l Observed by inspector l ACriviTY CO0 TENT RELEASE AMOUNT OF ACTIVITY LOCATION OF RELEASE y lZ l @o CF RELEASE (Z j@l N/A l l N/A l PERSONNi t e xPOSOES NuvaeR TYPE cESCRiPTiON@

l1171 l0 l 0 l 0 l@lZ l@l N/A i l

PE RSONNE L imu'n'iES Nuv6ER oESCRiPTiON@

li la 8l l0 7 9 l 0 l 0 l@l N/A 11 12 l

80 LOSS OF OR DAMAGE TO FACILITY TYPE DESCHIPTION l

l 1 l 98 I9 [Z_J@l N/A l I 7 10 80 l NRC USE oNLY ,

12 l oiSSuto l [N_j@oESCaiPTiON@

l N/A l lllllllllllll{

7 8 9 10 68 69 80 7.

NAME OF PREPARER

. . ay PHONE:

ATTACHMENT TO LICENSEE EVENT REPORT 80-002/0lT-1 Wisconsin Electric Power Company Point Beach Nuclear Plant Unit 1 Docket No. 50-266 Unit 1 was placed in cold shutdown at 0215 hours0.00249 days 0.0597 hours 3.554894e-4 weeks 8.18075e-5 months on March 6, 1980, for the 60 effective full power day steam generator testing program required by the Confirmatory Order of November 30, 1979. When taken off line the unit had primary-to-secondary leakage of approximately 30 gallons per day, which is well below the Technical Specification and Con-firmatory Order limits. The leak rate had been stable at this value since the unit returned to service on December 23, 1979, following steam generator repair work.

Prior to performing the 800 psi secondary-to-primary leak test, a 2000 psi primary-to-secondary dif ferential pressure leak test was conducted.

At 0400 hours0.00463 days 0.111 hours 6.613757e-4 weeks 1.522e-4 months on March 11, 1980, the 800 psi secondary-to-primary hydrostatic leak test of the Unit 1 "B" steam generator was completed. The "A" steam generator leak test was completed at 2020 hours0.0234 days 0.561 hours 0.00334 weeks 7.6861e-4 months the same day. No leaks were identified in the "A" steam generator. In the "B" steam generator, one tube (R23C4 4) was observed to be leaking approximately three drops per minute. Another tube (R8C37) appeared to be wet, but no water was dripping from the tube; a defect was later identified in this tube. The end of an existing explosive plug (R23C50) was wet, but no water was dripping from the plug.

Af ter performing the leak test, an eddy current inspection was performed in compliance with the Confirmatory Order of November 30, 1979. The eddy current program performed was mutually agreed upon with the NRC and was similar to the inspection program conducted in December 1979. The program consis ted of approximately 1,000 tubes in each steam generator concentrated mainly in the region where deep crevice tube defects have been found in the past. However , ove r 100 o f the tubes inspected in each generator were randomly located throughout the generator including the wedge area and the full length of these tubes was inspected. All the other tubes were inspected through the first support only.

Of the tubes inspected in the " A" steam generator, 24 were identified as having indications in the hot leg deep crevice region. Included in the 24 tubes are six tubes with undefinable indications which were plugged as a conservative measure. No eddy current indications were found at or above the top of the tubesheet. No degraded tube indications were l found in the cold leg side of those tubes which were inspected l for the full length. l All tubes in the " A" steam generator with indications were explosively plugged on March 17, 1980.

Of the tubes inspected in the "B" steam generator, 26 were identified as. having indications in the hot leg deep crevice region; one tube had a defect one-half inch above the tubesheet, and no defect was identified in the leaking tube.

Included in the 26 tubes are three tubes with undefinable indications which were plugged as a conservative measure.

No degraded tube indications were found in the cold leg side of those tubes which were inspected for the full length.

All tubes with indications, including the leaking tube, were explosively plugged on March 17, 1980 (see Table 2 for details) except for the hot leg side of three tubes which were pulled for labcratory examination. The three tubes pulled are:

R19C37 with a 5 8% de fect located one-half inch above the tubesheet.

R30C41 with a 47% deep crevice defect.

R26C5 3 with a 86% deep crevice defect that is similar to other undefinable indications.

All defects detected in both steam generators were extremely small volume. The experience accumulated during recent outages with multi-frequency eddy current equiprent and familiarity with Point Beach tubesheet signals had made definition of these small defects possible.

Four tubes located near tube R30C41 were explosively plugged as a' precautionary measure because R30C41 had not been completely cut prior to pulling it down about five inches. Plugging of these four tubes removed from service all adjacent tubes which may have been damaged.

Two explosive plugs were repaired on March 25, 1980.

These two plugs included the one identified as having a wet end during the March 11, 1980, hydrostatic leak test (R23C50),

and one (R29C41) which started to leak after removal of an adjacent tube.

Manual weld plugging of the removed tube holes was completed on March 28, 1980. An 800 psi secondary-to-primary hydrostatic leak test of the Unit 1 "B" steam generator was completed at 0400 hours0.00463 days 0.111 hours 6.613757e-4 weeks 1.522e-4 months the following morning.

Two leaking tubes (R25C48 and R23C55), one leaking explosive plug in the hot leg (R25C5 3) , and one leaking explosive plug in the cold leg (R22C48) were identified. The leaking tubes were explosively plugged and the plugs weld repaired on March 30 and 31, 1980. All of these tubes and plugs, except for the one in the cold leg, are adjacent to where a tube was pulled, an explosive plug installed or a weld repair made during this outage.

T +

A second 800 psi secondary-to-primary hydrostatic leak test was performed on March 31, 1980. This leak test identified a leaking tube (R26C52) and a leaking manual weld, both adjacent to a weld repair made after the March 28, 1980 leak test. The manual weld is one of the three made this outage to plug a removed tube hole, and the leak appeared to be from an area where some weld metal was possibly removed while preparing the adjacent tube for weld repair. The tube was explosively plugged on March 31, 1980, and the manual weld repair was completed on April 3, 1980.

A final 800 psi secondary-to-primary hydrostatic leak test of the Unit 1 "B" steam generator was performed at 1700 hours0.0197 days 0.472 hours 0.00281 weeks 6.4685e-4 months April 3, 1980. One tube (R29C53) was observed to be dripping at a very slow rate and two explosive plugs (R23C53 and R20C46) and one manual weld plug ( R19C37) were observed to be wet, but no water was dripping. The leaking tube was mechanically plugged on April 3. The wet plugs were not repaired since a wet end does not pose a significant primary-to-secondary leakage potential.

Tables 1, 2, and 3 give a summary of the tube plugging, eddy current results, and extent of examination in Unit 1 "A" and "B" steam generators for the effective full power day shutdown.

The total exposure accumulated during this outage was 268.9 man rem. Table 4 gives a breakdown of this exposure by job function.

The unit returned to line at 0312 hours0.00361 days 0.0867 hours 5.15873e-4 weeks 1.18716e-4 months on April 6, 1980 with a primary-to-secondary leakage rate of approximately ten gallons per day.

This event is reportable in accordance with Technical Specification 15.6.9.2.A.3.

1 1

J TABLE 1 "A" STEAM GENERATOR TUBES PLUGGED

, Tube Defect Location R12C19 80% 19-21" above tube end R07C22 29/96% 12/17" above tube end R18C22 66% 20" above tube end R10C23 41% 20" above tube end R07C24 83% 17-20" above tube end R08C24 79% 17-21" above tube end R25C45 69% 12-20" above tube end R20C48 85% 21" above tube end R09C49 90% 21" above tube end R17C50 85% 19" above tube end R19C50 97% 11" above tube end R20C50 97% 11" above tube end R12C59 87% 21" above tube end R12C61 83% 17" above tube end R14C6 3 83% 19" above tube end R15C66 60% 18" above tube end R20C41 91% 19" above tube end R25C4 3 73% 17" above tube end R15C28 Undefinable Indication 21" above tube end R28C34 Undefinable Indication 18-20" above tube end R28C35 Undefinable Indication 17" above tube end RllC46 Undefinable Indication 12-21" above tube end R29C32 Undefinable Indication 14" above tube end R08C27 Undefinable Indication 15-20" above tube end i

TABLE 2 "B" STEAM GENERATOR TUBES PLUGGED Tube De fect Location R18C26 75% 18" above tube end R13C26 73% 21" above tube end R13C33 71% 20" above tube end R06C34 91% 11" above tube end R20C35 68% 21" above tube end R08C37 89/100% 10-17"/3-6" above tube end R19C37 58% 1/2" above tubesheet R10 C41 70% 21" above tube end R30C41 47% 21" above tube end R30C42 48% 21" above tube end R22C46 76% 15" above tube end R24C48 84% 12" above tube end R30C48 85% 21" above tube end R25C49 84% 5" above tube end R20C51 99% 16" above tube end R23C54 86% 4-21" above tube end R23C57 56% 17" above tube end R21C58 83% 21" above tube end R02C72 92% 3" above tube end R14C59 75% 21" above tube end R21C63 62% 21" above tube end R12C6 7 66% 21" above tube end .

R25C55 74% 15" above tube end R26C53 86% 18" above tube end R30C43 Undefinable Indication 21" . above tube end R22C63 Undefinable Indication 21" above tube end R22C64 Undefinable Indication 20" above tube end R2 3C4 4 Leaking tube; no defect identified R25C48 Leaking tube; no defect identified R23C55 Leaking tube; no defect-identified R26CS2 Leaking tube; no defect identified R29C53 Leaking tube; not inspected R29C42 Plugged as a precautionary measure; possibly damaged during tube pulling.

R31C42 Plugged as a precautionary measure; possibly damaged during tube pulling R28C40 Plugged as a precautionary me as ure ; possibly damaged during tube pulling l

~!

l l

4 Tube Defect Location R30C40 Plugged as a precautionary measure; possibly damaged during tube pulling Explosive Plugs Repaired j R23C50 R25C53 R29C41 R22C48 (Cold Leg) i I

e I

i i

TABLE 3 EXTENT OF EDDY CURRENT AND RESULTS "A" Steam "B" Steam Tubes Plugged Generator Gene rator Deep Crevice Defects 18 23 Undefinable Indications (located within the tubesheet) 6 3 Defect above the Tubesheet 0 1 Leaking Tubes 0 5 Tubes Plugged as a Conservative Measure 0 4 Total Tubes Plugged 24 36 Explosive Plugs Repaired 0 4 Extent of Inspection Tubes Inspected Through the First Support 936 794

~

Tubes Inspected the Full Length 167 141 1,103 935 Indications Identified

<20% (Cold Leg) 1 0 20-39% 1** O 40-49% 1 2' 50-59% 0 2 60-69% 3 3 70-79% 2 7 80-89% 7' 7*

90-99% 5** 3 100% 0 1*

No Defects Detected 1,078 909

One tube contained both a 89% and a 100% defect.

- 0ne tube contained both a 29% and a 96% defect.

l l

., e TABLE 4 60 EFFECTIVE FULL POWER DAY SHUTDOWN

STEAM GENERATOR ACCUMULATED EXPOSURES Function Exposure (Man Rem)

Plant Steam Generator Support 3.8 Visual Inspections 3.3

{

Eddy Current 14.7 1 Tube Plugging 18.4 l Tube Pulling and Associated Repair 214.9 Health Physics Coverage 13.8 TOTAL 268.9 NOTE: The above values are based on dosimeter readings; actual TLD values should be somewhat less.

i i

).

i 1

e k

(

i a

i I

i i

- - - . ,io. . .- , --

, - _. . . , , ~ v

ML19309F345

Text

Navigation menu

Search