ML19247B659
| ML19247B659 | |
| Person / Time | |
|---|---|
| Site: | Farley  |
| Issue date: | 07/18/1979 |
| From: | James O'Reilly NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION II) |
| To: | Clayton F ALABAMA POWER CO. |
| References | |
| NUDOCS 7908130062 | |
| Download: ML19247B659 (2) | |
Text
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'o UNITED STATES E,
NUCLE AR REGULATORY COMMISSION 8'
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ATLANT A, GEORGIA 30303 JUL 181979 In Reply Refer To:
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5 Alabama Power Company Attn:
F. L. Clayton, Jr.
Executive Vice President Post Office Eox 2641 Birmingham, AJabama 35291 Gentlemen:
The attached enclosure, Circular 76-06, was inadvertently omitted in the July 17, 1979 issue of Information Notice 79-19.
Sincerely, "w'J V
Pett James P. O'Reilly Director
Enclosure:
Circular 76-06 t ;'
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'79081300 6
JUL 181979 Alabama Power Company
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A. R. Barton Executive Vice President Post Office Box 2641 Birmingham, Alabama 35291 J. T. Young Vice President-Production Post. Office Box 2641 Birmingham, Alabama 35291 C. Biddinger, Jr.
Manager-Corporate Quality Assurance Post Office Box 2641 Birmingham, Alabama 35291 H. O. Thrash Manager-Nuclear Generation Post Office Box 2641 Birmingham, Alabama 35291 H. G. Hairston, III Plant Manager Drawer 470 Ashford, Alabama 36312 R. E. Hollands, Jr.
QA Supervisor Post Office Box U Ashford, Alabama 36312
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p{. [9 JVlli Novembe r 26, 1976 IE Circular No. 76-06 STRESS CORPOSION CRACKS IN STAGNANT, LOW PPESSURE STAINLESS PIPING CONTAINING BORIC ACID SOLUTION AT PWR's DESCRIPTION OF CIBCimSTANCES: During the period November 7,1974 to November 1,1975, several incidents of through-wall cracking have necurred in the 10-inch, schedule 10 type 304 stainJess steel piping of the Reactor Building Spray and Decey Heat RRemoval Systeen at Arkansas Nuclear PJ ant No.1. On October 7, 1976, Virginia Electric and Power also reported through-wall cracking in the 10-inch schedule 40 type 304 stainless dicchstge piping of the "A" recirculation spray heat exchanger at Surry Unit No. 2. A recent inspection of Unit 1 Containnent Recirculation Spray Piping revealed cracking similar 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 1.ine at the Cinna facility vah reported by the licensee. i l Information received on the retallurgical analysis conducted to date indicates that the fs13ures were the result of intergranular stress corrosion cracking that initinted on the inside of the piping. A commonality of f actors observed associated with the corrosion mechanis: l vere: 1. The cracks were adjacent to and propagated along veld zones of the thin-walled low pressure piping, not part of the reactor coolant i system. i 2. Cracking occurred in piping containing relatively stagnant boric acid solution not required for normal operating conditions. i 3. Analysis of surface producta at this time indicate a chloride ion l interaction with oxide formation in the relatively stagnant boric acid solution as the probable corrodant, with the state of strese probably due to welding and/or fabrication. The source of the chloride ion is not definitely known. However.at ANO-1 the chlorides and sulfide level observed in the sur f ace tarnish film near velds is believed to have been introduced into the piping during testing of the sodium thinsulf ate discharge valves, or valve Icakage. Similarly, at Cinna the chlorides and potential oxygen 0 [ 9 ~ 't 0 DL' 9 1 I.
o 9 USNRC REGt' ATtANTA e.c IE Circular No. 76h06dg[ (7 P l. 3 (- November 26, 1976 availability were assumed to have been present since original construction of the borated vator storage tank which is vented to atmosphere. Corrosion attack at Surry is attributed to in-leakage of chlorides through recirculation spray 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 systccs which are not frequently flushed, or which contain nonflowing liquids. This program should include consideration of hydrostatic testing in acccrdance with ASME Code Section XI rules (1974 Edition) for all active systecc required for safety injection and containment spray, including their recirculation modes, from source of water supply up to the second isolation valve of the primary system. Similar tests should be considered for other safety-related piping systecs. 2. Your program should also consider volunetric examination of a representar.ive number of circumferential pipe welds by non-destructive examination techniques. Such examinations should be perf ormed generally in accordance with Appendix I of Section XI of the ASME Code, except that the examined area should cover a distance of approximately six (6) times the pipe wall thickness (but not 3 css than 2 inches and need not exceed 8 inches) on each side of the weld. Supplementary examination techniqvcs, such as radiography, should be used where necessary for evaluation or confirmation of ultrasonic indications resulting f rom such cxamination. 3. A report describing your program and schedule for these inspec-tions should he submitted within 30 days af ter receipt of this Circular. 4. The NRC Regional Of fice should be informed within"24 hours, of any adverne findings resulting during condestructive evaluation of the accensibic piping welds identified above. 5. A summaty report of the examinations and evaluation of results should be subm1Lted within 60 days from the date of ccepletion of proposed testing and examinations. 9 4 J ') I r J e i r
O -7 1. ~ ,}' U Sf1 R C R E Gi % A TI ' N T/.. f ~ ~ ' IE circuler No. 76-06 ; 9 'IU L 17
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3 November 26, 1976 i should also include a brief description of } Tais sum =ary report plant conditions, operating procedures or other activities the ef fluent chemistry will naintain which provide assurance that 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. i Approval of NRC requirements for reports concerning possible Eeneric [ problems has been obtained under 44 U.S.C 3152 f rom the U.S. Ceneral Accounting Of fice. (GAO Approval B-180255 (R0062), expires 7/31/77.) a h i a i e I f 4 f 9 .i I}}