ML19320D506

LER 80-018/01T-0:on 800701,unit Was Shut Down Due to Leaking Tube in Hot Leg of Vertical Steam Generator 12,Westinghouse Series 51.Cause Not Stated.Defective Tube Will Be Plugged

ML19320D506
Person / Time
Site:	Prairie Island
Issue date:	07/15/1980
From:	Hunstad A NORTHERN STATES POWER CO.
To:	NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION III)
Shared Package
ML19320D501	List: ML19320D500 ML19320D506
References
LER-80-018-01T, LER-80-18-1T, NUDOCS 8007210444
Download: ML19320D506 (2)

Text

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't Pagle 1 of 2 y NRC FORM 304 U.L NUCLE AR REiUL ATCGY COMMISSION  ;

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(j LICENSEE EVENT REPORT CONTROL BLOCK: l 1

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EVENT DATE 74 75 REPORT DtTE to EVENT OESCRIPTION AND PROB ABLE CONSEQUENCES h O 2 I On June 29th, a small primary-to-secondary leak was indicated by trace readines of I O 3 I xenon gas in the air eiector discharge and by tritium and other radioisotones in 1 0 4 l secondary side water samoles in #12 Steam Canerntor. Thd lankago una decarmined l I

O 6 l to be about 0.004 nom. The lankage incranaad alnuly une41 nn .Tn1 v 1 4e uno l 0 6 l cn1cn1 mend en ho n1 on. on, tw .m4 g ug g g g .ay ._, l 0 7 i The leaking tube is in the hot leg of No. 12 Steam Generator. Row 2 Column 21. I O a l Eddy current examination of the tube showed the defect to be 10 inches down into I 7 8 9 80 E CO E $ SC E COMPONENT CODE S SU O 9 l C l B l@ y@' y @ l H l Tl E lX l C l H l@ USCODEW@ W@

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44 47 CAUSE DESCRIPTION AND CORRECTIVE ACTIONS 27 1 o l Tube failure in a Westinnhouse Series 51 Vertical Steam Generator. Defective tube l 1 i l will be niunned. Tube inanection in accordance with Tech Snec 4.12. A.3.a is beine I i 7 1 done. 1 i a l I gi I 7 8 9 80 STA S %PCWER OTHER STATUS DSO Y DISCOVERY DESCRIPTION i 6

(.XJ@ l1l010l@l NA l (_Aj@l Operator Observation l ACTIVITY CONTENT RELEASED OF RELEASE AMOUNT OF ACTIVITY LOCATION CF RELEASE i e l_M_j @ d @ l 0.75 Ci I l Air Eiector Discharge l 7 8 9 10 ft 44 45 80 PERSONNEL EXPOSURES NUM8ER TYPE DESCRIPTION i i 1010l0' h d @l" NA l

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LOSS OF OR DAMAGE TO FACILITY TYPE DESCRIPTION 1 9 l.L_j@l 1.oss of neneratina caoability for about 20 days. l 7 8 9 10 80 DESCRIPTION e 2 O [.y ISSU]E @lPress release 6 30 80 - - l lIll1llll1Ill}

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NAME OF PREPARER A k nstad PHONE:

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Northern States Power Company 80-018 Prairie Island Nuclear Generating Plant Page 2 of 2 LICENSEE EVENT REPORT (con't) 7-15-80 EVENT DESCLIP's'10N AND PROBABLE CONSEQUENCES (con't) the (21") tube sheet and about 1-1/2 inches long (100% defect indicated) .

Eddy current examination is nearly complete. Two indications of tube degradation (30-35%) at the tube support plates in the cold leg of No. 11 Steam Generator have also been found.

A similar event is RO 77-40. The effect of this event on the health and safety of the public is minimal.

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