ML19254F077
| ML19254F077 | |
| Person / Time | |
|---|---|
| Site: | Bailly |
| Issue date: | 10/29/1979 |
| From: | James Keppler NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION III) |
| To: | Shorb E NORTHERN INDIANA PUBLIC SERVICE CO. |
| References | |
| NUDOCS 7911060120 | |
| Download: ML19254F077 (1) | |
Text
4'pa arcq*
UNITED STATES NUCLEAR REGULATORY COMMISSION
,,, 7 c
REGION ill o,
f 799 ROOSEVELT ROAD e
4 j'
GLEN ELLYN. BLLINOIS 60137 Docket No. 50-367 007 2 r 1979 Northern Indiana Public Service Company ATTN:
Mr. Eugene M. Shorb Senior Vice President 5265 Hohman Avenue Hammond, IN 46325 Gentlemen:
The enclosed IE Bulletin No. 79-17, Revision 1 is forwarded to you for information. No written response is required. However, the potential corro-sion behavior of safety related systems as it regards your plant over the long term should be taken into consideration.
If you desire additional information concerning this matter, please contact this office.
Sincerely, A Ma = MN ve ames G. Keppler Director
Enclosure:
IE Bulletin 1:o. 79-17, Revision 1 cc w/ encl:
Central Files D; rector, NRR/DPM Director, NRR/ DOR PDR Local PDR NSIC TIC Mr. Dean Hansell, Office of Assistant Attorney General lJ g g o 60 l N
UNITED STATES SSINS No. 6820 l4UCLEAR REGULATORY COMMISSION Accession No. Office OF INSPECTION AND ENFORCEMENT 79082201) WASHINGTON, D.C. 20555 y October 29, 1979 IE Bulletin No. 79-17 Revision 1 J PIPE CRACKS IN STAGNANT BORATED WATER SYSTEMS AT PWR PLANTS Description of Circumstances: IE Bulletin No. 79-17, issued July 26, 1979, experienced to date in safety related stainless steel piping systems at PWRprovi plants. R1 license within a specified 90-day time frame.Certain actions were required o R1 R1 After several discussions with licensee owner group representatives and inspection R1 agencies it has been determined that the requirements of Item 2, particularly the ultrasonic examination, may be impraci.ical because of unavailability of R1 qualified personnel in certain cases to complete the inspections within the time R1 specified by the Bulletin. R1 To alleviate this situation and allow licensees the R1 resources of improved ultrasonic inspection capabilities, a time extension and clarifications to the bulletin have been made. R1 affected items of the original bulletin. These are referenced to the R1 R1 During the period of November 1974 to February 1977 a nuraber of cracking inciaents have been experienced in safety-related stainless steel piping systems and por-tions of systems which contain oxygenated, stagnant or essentially stagnant 5or-ated water. Metallurgical investigations revealed these cracks occurred in the weld heat affected zone of 8-inch to 10-inch type 304 material (schedule 10 and 40), initiating on the piping I.D. surf ace and propagating in either an inter-granular or transgranular mode typical of Stress Corrosion Cracking. Analysis indicated the probable corrodents to be chloride and oxyger, contamination in the affected systems. Plants affected up to this time were Arkansas Nuclear Unit 1, R. E. Ginna, H. B. Robinson Unit 2, Crystal River Unit 3, San Onofre Unit 1, and Surry Units 1 and 2. of the apparent generic nature of the problem.The NRC issued Circular No. 76-During the refueling outage of Three Mile Island Unit I which began in February of this year, visual inspections disclosed five (5) through wall cracks at welds in the spent fuel cooling system piping and one (1) at a weld in the decay heat removal system. and later confirmed by liquid penetrant tests.These cracks were found as a resu This initial identification of cracking was reported to the NRC in a Licensee Event Report (LER) dated May 16, 1979. A preliminary metallurgical analysis was performed by the licensee on a section of cracked and leaking weld joi R1 - Identifies those additions or re Entire document previously entered into system under: ANO No. of pages:
O t \\ U 1 November 26, 1976 IE Circular No. 76-06 STRESS CORROSION CRACKS IN STAGNANT, I4W PRESSURE STAINLESS PIPING CONTAINING BORIC ACID SOLUTION AT PWR's DESCRIPTION OT CIRCD1 STANCES: q During the period Nove=ber 7,1974 to November 1,1975, ceveral incidents of through-vall cracking have occurred in the 10-inch, schedule 10 type 304 stainless st'ael piping of the Reactor Building Spray and Deesy Eeat Re= ova) Systems at Arkansas Nuclear Plant No.1. On October 7,1976. Virginia Electric and Power also reported through-vall cracking in the lo-inch schedule 40 type 30!. stainless dischar;e piping of the "A" recirculation spray heat exchanger at Surry D:ft No. 2. A recent inspection of Unit 1 Containment Recirculation Spray Piping revealed cracking zinilar to Unit 2. On October 8,1976, another incident of similer cracking in 8-inch schedule 10 type 30I. stainless, piping of the Srfety Injection Pump Suction 1.ine st the Cinna facility was reported by the licensee. Inforation received on the netallurgical analysis conducted to date indicates that the failures were the result of intergrenular stress corrosion cracking, that initiated on the inside of the piping. A cecnennlity of facters observed associated with the corrosion = ether.iss were: 1. The cracks v*re adjacent to and propagated along weld zones of the thin-vallad low pressure piping, not part of the reactor coolant system. 2. Cracking occurred in piping containing relatively stagnant boric acid solution tot required for normal operating cenditions. 3. Analysis of surface products at this time indicate a chloride ion interaction with oxide formation in the relativaly stagnant boric acid solution as the probable corrodant, with the state of stress probably due to velding and/or f abrication. The source of the chloride ion is not dafinitely knesa. Bovever,at ANO-1 the chlorides and sulfide level observed in the surface tarnish film near velds is believed to have been introduced into the piping during testing of the sodiu:n thiosulfate discharge valves, or valve leakage. 54-41arly, at Ginns the chlorides and potential oxygen DUPLICATE DOCUMENT Entire document previously entered into system under: I ANO u / No. of pages: 6 O}}