ML17261A139

LER 79-008/03X-1 on 790406:during Maint on Boric Acid Flow Control Valve,Leaks Noted on Valve Outlet 1-inch Nipple. Caused by External Caustic Pitting.Actions to Minimize Caustics & Chlorides Are Being Taken

ML17261A139
Person / Time
Site:	Ginna
Issue date:	08/21/1979
From:	Spector S ROCHESTER GAS & ELECTRIC CORP.
To:	NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION I)
Shared Package
ML17244A791	List: ML17244A790 ML17261A139
References
LER-79-008-03X, LER-79-8-3X, NUDOCS 7908280731
Download: ML17261A139 (4)

Text

INRC FORM366 U. S. NUCLEAR REGULATORY COMMISSION l

I7377I LER 79-008/03X-1 Update Report Previous Report Date 5/7/79 CONTROL BLOCK:

~ENSEE Qi EVENT REPORT

~

(PLEASE PRINT OR TYPE ALL REQUIRED INFORMATIONI (CAR 2229)

I I~!0 7

1 8 9 NY RE LICENSEE CODE G1Q200 '14 15 LICENSE NUMBER 0 - 0 0

'25 Q'4 26 LICENSE TYPE

' 30 PE~QE 57 CAT 58

<<CON'T i~Oi 7 8

~LQB 60 61 0 5 0 0 0 DOCKET NUMBER 2 4 4 68 7

69 0 4 0 EVENT DATE 6 7 9 74 s

75 0 8 2 1 REPORT DATE 7 9 80 Q

EVENT DESCRIPTION AND PROBABLE CONSEQUENCES Q10 During maintenance on boric acid flow control valve leaks were noted on valve outlet 1~03 1 nipple (T. S . 6.9.2 .b. (4)) . Two flow paths from boric acid tanks to RCS were

<<~ 4 verified. Nipple was replaced with sch 40 nipple. Later, nipples, check valve and coupling from control valve to coupling were replaced.

~ ~<<0 e

(~O7 I~os

.7 8 9 80 SYSTEM CAUSE CAUSE COMP. VAI.VE CODE CODE SUBCODE COMPONENT CODE SUBCODE SUBCODE I~Os ~PC Q<<1 E Q12 Uc Q13 P I P E X X Q<<4 UA P<<6 ~Z Q16 7 8 9 10 11 12 13 18 19 20 SEQUENTIAL OCCURRENCE REPORT REVISION EVENT YEAR U

REPORT NO. CODE TYPE Q17 LER)RO REPORT L77I 21 22 23 UOOOSJ 24 26 UH 27

~03 28 29 UX 30 U

31 NO.

32 1

ACTION FUTURE EFFECT SHUTDOWN ATTACHMENT NPRDQ PRIME COMP. COMPONENT TAKEN ACTION ON PLANT METHOD HOURS Q22 SUBMITTED FORM SUB. SUPPLIER MANUFACTURER UcPT.UcPE UzPE UZP21 37 o o o o ~XP23 UNQ24 UNP>> z 9 9 9 P26 33 34 35 36 40 41 42 43 44 47 CAUSE DESCRIPTION AND CORRECTIVE ACTIONS Q27 o Severe external caustic pitting probably started process causing leaks. Metallurgical analysis identified this combined with throughwall chloride stress corrosion cracking.

j~j2 The 1" nipple is 3-'," long sch 10 SS, heat traced, normal operating pres sure 100 psig .

3 Other heat traced piping areas involving similar conditions examined; no problems found. Actions to minimize caustics and chlorides on pipe due to insulation, heat 4 trace and other materials are bein taken.

'.7 8 9 80 FACILITY METHOD OF STATUS  % POWER OTHER STATUS DISCOVERY DISCOVERY DESCRIPTION Q32 7~18 E Q28 ~09 2 Q28 NA ~AQ31 Noticed durin maintenance on ad acent 7 8 9 10 12 13 44 45 46 v ve 80 ACTIVITY CONTENT RELEASED OF RELEASE AMOUNT OF ACTIVITY LOCATION OF RELEASE Q

(~16 ~ZP33 ~ZP, NA 7 8 9 10 11 44 45 80 PERSONNEL EXPOSURES NUMBER TYPE DESCRIPTION Q39

~00 0 Q37 ~ZQ38 NA 7 8 9 11 12 13 80 PERSONNEL INJURIES NUMBER DESCRIPTIONQ l~<<8 ~00 0 Q46 NA 7 8 9 11 12 80 LOSS OF OR DAMAGE TO FACILITY TYPE DESCRIPTION Q43 Lz IQE NA 790838073 (

8 9 10 80

'H~Z ISSUED PJQ44 PUBLICITY DESCRIPTION ~ NA 4

NRC USE ONLY 8 9 10 68 69 80 48 NAME OF PREPARER S. Spector PHoNE. 7 1 6 546-2 700 ext . 2 9 1-2 1 5

1 Attachment to LER 79-008/03X-1 Rochester Gas and Electric Corporation R. E. Ginna Nuclear Power Plant, Unit No. 1 Docket No. 50-244 W9ile performing maintenance on boric acid flow control valve PCV-llOA, a leak was noted on the adjacent piping. Two flow paths from the boric acid tanks to the Reactor Coolant System were verified.

The leaking pipe section was a 3-'," long 1" schedule 10 stainless steel. It is heat traced and normal operating pressure is 100 psig. The external surface exhibited numerous deep pitting holes. The nipple was replaced, and later the. nipple, adjacent check valve, nipple and coupling were replaced.

Metallurgical analysis has identified the mechanism causing the leaks to be severe caustic pitting combined with throughwall chloride stress corrosion cracking. Seventeen sections of heat traced stainless steel piping, containing varying concentrations of boric acid, have been randomly selected for external visual inspection to determine the extent of the problem. Parti-cular interest was given to areas of high stress and areas that may have had numerous wetting/drying cycles due to accidental spills or leaking valves.

These inspections revealed that all the piping was in excellent condition, with no signs of this phenomenon.

These findings indicate that local external causes probably initiated this process, and the replacement of piping, valve and fittings in this area should resolve the problem. Actions to further minimize chloride and caustics on the piping due to insulation, heat tracing and other materials are being taken.