ML17261A158

LER 79-022/01T-0:on 791201,during Normal Operations,Found Two Leaking Tubes & Eleven Other Tubes W/Pluggable Defects. Caused by Possible Thermal,Hydraulic & Mechanical Loading in Wedge Area & by Possible Residual Caustics Concentration

ML17261A158
Person / Time
Site:	Ginna
Issue date:	12/14/1979
From:	Curtis A ROCHESTER GAS & ELECTRIC CORP.
To:	NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION I)
Shared Package
ML17261A157	List: ML17261A156 ML17261A158
References
LER-79-022-01T, LER-79-22-1T, NUDOCS 7912190521
Download: ML17261A158 (4)

Text

9 717 NRC FORM 366 I7 77 I,4 8 CONTROL BLOCK:

I t 6 Q1 79-022/01T-0 LlCENSEE EVENT REPORT U. S. NUCLEAR REGULATORY COMMISSION (PLEASE PRINT OR TYPE ALL REQUIRED INFORMATION)

Q4~

~O 7 8 9 NY RE 61Q20 LICENSEE CODE 14 15 0 0 0 0 LICENSE NUMBER 0 0 0 0 25 Q3 26 4 1 1 1

!.ICENSE TYPE 1

30 57 CAT 58 QE CON'T

~01 """'~LQ60 5 0 0 0 2 4 4Q71 2 0 EVENT DATE 1 7 9QB1 74 75 2 1 4 REPORT DATE 7 9 80 QB 7 8 60 61 DOCKET NUMBER EVENT DESCRIPTION AND PROBABLE CONSEQUENCES Q10 During normal operations air ejector and blowdown rad monitors alarmed. Analysis of B

~O3 steam gen. (SG) blowdown verified activity from calculated 0.007 gpm leak rate. Hydro est located leaking tubes (R43C54 & R15C37). Eddy current test located defects just

~O6 bove tube sheet in R43C54 and approx. 4 in. below top of tube sheet in R15C37, and

~OB 1 other tubes with pluggable defects. (T.S. 6.9.2.a. (3)) Defects in periphery were

~O7 similar to those reported in LER's 77-08, 78-03 and 79-006, and others with defects

~OB below top of tube sheet, also reported in 79-006. 80 7 8 SYSTEM CAUSE CAUSE COMP. VALVE CODE CODE SUBCODE COMPONENT CODE SUBCODE SUBCODE

~OB ~Qg 10 Qll E Q12 UDI 12 Q13 13 H T E X C H 18 Q14 UF 19 OEE UZ 20 Q18 7 8 9 11 SEQUENTIAL OCCURRENCE REPORT REVISION Q17 LERIRO REPQRT EVENT YEAR

~79 U ~02 REPORT NO.

2 U~

CODE LODIJ TYPE UT 30 31 U0 32 NO.

21 22 23 24 26 27 28 29 ACTION FUTURE EFFECT SHUTDOWN ATTACHMENT NPRDQ PRIME COMP, COMPONENT TAKEN ACTION UOE ON PLANT

~AO29 METHOD UO2 0 HOURS Q22 2 4 9 SUBMITTED UO>>

FORM SUB.

UOE SUPPLIER UHO>>

MANUFACTURER'18

' '28 33 34 35 36 37 40 41 42 43 44 47 CAUSE DESCRIPTION AND CORRECTIVE ACTIONS Q27 o Possible thermal, hydraulic and mechanical loading in wedge area, and possible con-centration of residual caustics. The 13 tubes were plugged. SG is Westinghouse series 44 with inconel tubes size 0.875 in. OD, 0.50 in. walls.

~l5 7

7 8

8 9

E ACTIVITY 9

Q28 Q33

~

10 CONTENT RELEASED OF RELEASE z ~ZQ34 10 12 Q29 13 AMOUNT OF ACTIVITY NA Q

44 44 METHOD OF DISCOVERY

~CQ31 45 45 46 Rad monitors and sample NA DISCOVERY DESCRIPTION +32 LOCATION OF RELEASE Q36 anaIysis 80 80 80 PERSONNEL EXPOSURES NUMBER TYPE DESCRIPTION 7 ~00 0 O37 UZQ38 13 NA

'80 7 8 9 11 12 PERSONNEL INJURIES NUMBER DESCRIPTIONQ41 7 8 L0 9

o ojO 11 12 NA 80 LOSS OF OR DAMAGE TO FACILITY TYPE DESCRIPTION Q43 z NA 7 8 9 ISSUED Q42 10 PUBLICITY DESCRIPTION Q46 News release was made December 3, 1979.

'F 918190 NZ ].2 o O ~YQ44

'7 10 68 69 80 o 8 9 A. E. Curtis III 716/546-2700,ext. 2329 o NAME OF PREPARER

~, r Rochester Gas and Electric Corporation R. E. Ginna Nuclear Power Plant, Unit No. 1 Docket No. 50-244 Event Descri tion During normal operations air ejector and blowdown rad monitors alarmed. Analysis of B steam generator (SG) blowdown verified activity from calculated 0.007 gpm leak rate. Hydrostatic test located leaking tubes (R43C54) and (R15C37). Eddy current testing located the defect just above the tube sheet on R43C54 and approximately four (4) inches below the top of the tube sheet on R15C37. The eddy current examination of over 27% of the generator revealed eleven (ll) other tubes with pluggable defects, R43C57 in the periphery and R15C38, R16C47, R17C37, R17C38, R17C42, R17C43, R18C37, R18C40, R18C43 and R18C44 in the area of the other leaker. The defects found in the periphery tubes, R43C54 and R43C57, were similar to those reported in March 1979 (LER 79-006) with defect depth of 100% and approximately 80% respectively. The other leaker, R15C37, and the other ten tubes with multiple (OD) crack indications were also simi-lar to what was reported in LER 79-006. These thirteen tubes were plugged.

There were no health or safety consequences to the public or to plant personnel due to this event.

Cause Descri tion The OD indications below the top of the tube sheet of tubes R15C37, R15C38, R16C47, R17C37, R17C38, R17C42, R17C43, R18C37, R18C40, R18C43 and R18C44 are apparently due to a stress corrosion mechanism caused by a probable concentration of caustics during previous years opera-tion. The defect indications ranged in through wall penetration from 20% to approximately 60% multiple crack indication from 3 inches to 15 inches below the top of the tube sheet.

The leak associated with R43C54 is apparently a large volume type of OD defect just above the top of the tube sheet. A similar 80% defect in R43C57 was also a large volume type of eddy current indication. These tubes are located in the same area (wedge area $ 4) where there has been primary to secondary leakage in the past and other tubes have been plugged for similar defects. The probable cause for these defects is a thermal hydraulic and mechanical loading of these tubes in this wedge area. No other indications similar to these defects were found in other periphery tubes examined.

With the exception of these thirteen tubes, the B steam generator continues to show no significant changes. The full flow condensate polishers are doing an excellent job at maintaining optimum chemistry in the feedwater system. Rochester Gas and Electric will continue to be involved in the Steam Generator Owners Group to apply any new applicable technology which will assist in maintaining steam generator integrity.