ML19322E837

LER 80-002/01T-0:on 800311,during shutdown,800 Psi secondary-to-primary Hydrostatic Leak Test of B Steam Generator Revealed Tube R23C44 Leaking,Tube R8C37 Wet & Plug End R23C50 Wet.Tube Holes Will Be Weld Plugged

ML19322E837
Person / Time
Site:	Point Beach
Issue date:	03/25/1980
From:	Fay C WISCONSIN ELECTRIC POWER CO.
To:	NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION III)
Shared Package
ML19322E829	List: ML19322E828 ML19322E837
References
LER-80-002-01T-01, LER-80-2-1T-1, NUDOCS 8004020344
Download: ML19322E837 (5)

Text

NRC FORM 366

• U. S. NUCLE AR REGULATORY COMMISSION (7 7M

• LICENSEE EVENT REPORT ,

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7 8 NLM86 R 63 EVENT OATE T OArE EVENT DESCRIPTION AND PROBABLE CONSEQUENCES h f5T 1IWith the unit in cold shutdown for a required 60 effective full power l PT31 I day steam generator testing program, an 800 psi' secondary-to-primary

,o,,,; hydrostatic leak test of the steam generators was performed on 3-11-80. ,

No leaks were identified in the "A" steam generator. Inspection of the "B" steam generator revealed one tube (R23C44) leaking approximately 3 drops / min., one tube (R8C37) that appeared wet .nd one wec plug end (R23C50). This event is reportable per T. S. 15.6.9.2.A.3 and similar 7 8 Sto otners. So

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4J lWl1l2l0lg 44 47 CAUSE DESCRIPTION AND CORRECTIVE ACTIONS h g lA previously scheduled eddy current inspection program was performed.  ;

24 tubes in the "A" steam generator and 32 tubes in the "B" steam generator were explosively plugged except for the hot leg side of three tubes in the "B" steam t,Tenerator which have been pulled for laboratory examination. The three tube holes will be weld plugaed and two leakina ITTTI 1 oreviously T)1ucced tubes wi11 be recair welded. A h9drostatic test willi 7 e abe m

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l ATTACHMENT TO LICENSEE EVENT REPORT 80-002/OlT-0  :

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 <br />0.0597 hours <br />3.554894e-4 weeks <br />8.18075e-5 months <br /> on 1 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 I l

leakage of approximately 30 gallons per day, which is well below the Technical Specification and Confirmatory Order limits. The  ;

leak rate haJ been stable at this valta 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 differential pressure leak test was conducted.

At 0400 hours0.00463 days <br />0.111 hours <br />6.613757e-4 weeks <br />1.522e-4 months <br /> 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 <br />0.561 hours <br />0.00334 weeks <br />7.6861e-4 months <br /> the same day. No leaks were identified in the "A" steam generator. In the "B" steam generator, one tube (R2C44) 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.

After 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 nutually agreed upon with the NRC and was similar to the inspection program conducted in December 1979. The program consisted 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, over 100 of 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 a're 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 found in the cold leg side of those tubes which were inspected for the full length.

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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 idencified 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 indica-tions 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 are being pulled for laboratory examination. The three tubes being pulled are:

' R19C37 with a 58% defect located one-half inch above the tubesheet.

R30C41 with a 47% deep crevice defect.

R26C53 with a 86% deep crevice defect that is similar to other undefinable indications.

The hot leg ends of these tubes have been weld plugged following tube pulling. Two previously plugged tubes (R23C50 and R29C41) have also been weld repaired. Four tubes which may have been damaged during tube pulling were also plugged as a precautionary measure.,

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

The unit is expected to return on line on approximately March 29 after tube pulling, weld plugging, hydrostatic testing, and crevice flush operation.

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

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 R14C63 80% 19" above tube end R15C66 60% 18" above tube end R20C41 91% 19" above tube end R25C43 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 R29C52 Undefinable Indication 14" above tube end R08C27 Undefinable Indication 15-20" above tube end e

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TABLE 2 "B" STEAM GENERATOR TUBES PLUGGED Tube Defect Location s

R18C25 75% 18" above tube end R13C2d 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% 5" above tube end R19C37 58% 1/2" above tubesheet R10C41 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 tubo 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 R12C67 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 R23C44 Leaking tube; no defect identified R21C42 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 measure; possibly damaged ,

during tube pulling R30C40 Plugged as a precautionary measure; possibly damaged during tube pulling S 8 semedp en =<e .-

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