ML19225C858
| ML19225C858 | |
| Person / Time | |
|---|---|
| Site: | Summer  |
| Issue date: | 07/18/1979 |
| From: | James O'Reilly NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION II) |
| To: | Mary Johnson SOUTH CAROLINA ELECTRIC & GAS CO. |
| References | |
| NUDOCS 7908030019 | |
| Download: ML19225C858 (2) | |
Text
UNITED STATES jyt,}gjg7g
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NUCLEAR REGULATORY COMMISSION REGION 11
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\\v JUL 181979 In Reply Refer To:
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South Carolina Electric and Cas Company Attn:
M. C. Johnson, Vice President Special Services and Purchasiry, Post Office Box 764 Columbia, South Carolina 29218 Gentlemen:
The attached enclosure, Circular 76-06, was inadvertently omitted in the July 17, 1979 issue of Informatio.' Notice 79-19.
Sincerely, B
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V Pett James P. O'Reilly Director
Enclosure:
Circular 76-06 440 15)-
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JUL 181979 4
South Carolina Electric and Gas Company cc w/ encl:
T. B. Conners, Jr.
Conners, Moore and Corber 1747 Pennsylvania Avenue, N.t!.
Washington, D.C.
20006 A. A. Smith Quality Assurance Post Office Sox 8 29065 Jenkinsville, South Carniina O. S. Bradhsm, Manager Nuclear Operations Post Of fice Bo:t J 29065 Jenkinsville, South Carolina 440 153
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November 26, 1976 IE Circular No. 76-06 STFISS CORPOSION CFACKS IN STAGNANT, LOW PRESSURE STAINLESS P1 PING CONTAINING BORIC ACID SOLUTION AT FWR's DESCRIPTION OF C1BCIMSTANCES: During the period November 7, 1974 to November 1, 1975, several incidents of through-wall cracking have occurred in the 10-inch, schedule 10 type 304 stain 2 css steel piping of the Reactor Building Spray and Decay Heat ' Removal Sy-teen at Arkansan Nucir ar Plant No. 1.
- t': 6ober 7, 1976 Virginia Electric and Power also reported through-vall cracking in the 10-inch sche.dule 40 type 304 stainless diccharge piping of the "A" recirculation spray heat exchanger at Surry Unit s
No. 2. A recent inspection of Unit 1 Containnent Recirculatio'1 Spray Piping revealed cracking i,imilar to Unit 2. On October 8, 1976, another incident of similar cracking in 8-inch schedule 10 type 304 stainless piping of the Sefety Injection Pump Suction Line at the Cinna facility was reported by the licensee. Inforration roccived on the r.etallurgical analysis conducted to date indicates that the failures were tho result of intergranular stress corrosion cracking that initiated nn the inaide of the piping. A cormonalj ty of f actorn observed associated with the corrosion nechanism I were: 1 1. he cracks were adjacent to and propagated along veld zones of the thin-valled low pressure piping, not part of the reactor coolant systeu. l 2. Cracking occurred in piping containing rr.3atively stagnant boric acid solution not required for norcal operating conditions. i 3. Analysis of surface proc'ueta at this timc indicate a chloride ion { interaction with oxide formation in the relativaly stagnant boric acid solution as the probable corredant, with the state of stresc l probably due to welding and/or ic'urication, n e source of the chloride ion is not definitely known. However.at LNO-1 the chlorides and sulfide level chucrved in the surface tarnish film near welds is believcd to have been introduced into the piping during tenting of the sodium thinsulf ate discharge valves, or valve Icakage. Similarly, at Cinna th:: chlorides and potential oxygen ( '4.40 159 ~ i. V i, I.
'] ... I Q r USNRC REGi ~ t eTLANTA.6 IE Circular No. 76-eJ U L 17 Pl'3L Nove=ber 26, 1976 availability were cssumed to have been present since original construction of the borated water storage tank which is vented to atmosphere. Corrosion attack at Surry is attributed to in-leakage of chlorides through recirculatior, ray heat exchange tubing, allowing . buildup of contaminated water in an otherwise normally dry spray piping. ACTION TO BE TAKEN BY LICENSEE: 1. Provide a description of your program for assuring continued integrity of those safety-related piping systees which are not frequently flushed, or which contain nonflowing liquids. This program should include consideration of hydrostatic testing in accordance with ASME Code Section XI rule = (1974 Edition) for all active systems required for safety injection and contain=ent spray, including their recirculation mades, frein source of water supply up to the second isolation valve of the primary system. Similar tests should be considered for other safety-related piping systems. 2. Your program should also consider voluraetric exacination of a representative number of circumferential pipe welds by non-destructive examination techniquas. Such examinations should be performed generally in accordance with Appendix I of Section XI of the ASME Code, except that the examined crea should cover a distance of approximately six (6) times the pipe wall thickness (but not 1 css than 2 inches and need not exceed 8 inches) on each side of the weld. Supplementary exaraination technigees, such as radiography, should be used where necessary for evaluation or :nnfirmation of ultrasonic indications resulting f rom such r xamination. 3. A report 4,eeribing your program and schedule for these inspec-tions should he submit ts d sithin M days af ter receipt of this Circular. The NRC lteF onal Office should be informed within"2T hours, i 4. of any adverne findinCs resulting during nondestructive evaluation of the acce u ibic p! ping welds identified above. 5. A sumaty report of the exarcinationc and evaluation of results should be suhrciLted within 60 days f rom the date of completion of proposed testing and examinations. /65 ~440 p4c
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~~ i 3i 1 Noverber 26, 1976 IE Circular No. 76-06 I, should also include r brief dencription of I This st==ary report plant conditions, operating procedures or other activities which provide assurance that the effluent chemistry will it.aintain low levels of potential corrodants in such relatively stagnant l regions within the piping. nubmitted to the Director of this office, Your responsen should be Division with a copy to the NRC Office of Inspection and Enforcement. of Reactor Inspection Programs, Washington, D.C. 20555. Approval of NRC rea.uirements for reports concerning possible generic problems has been obtained under 44 U.S.C 3152 f rom the U.S. General Accounting Office. (GAO n.roval B-180255 (R0062), expires 7/31/77.) J 31diUM b tiuME&" L, 9 i b i k l I 440 W4 li ~ .I -l ,}}