ML19254F069
| ML19254F069 | |
| Person / Time | |
|---|---|
| Site: | Zion File:ZionSolutions icon.png |
| Issue date: | 10/30/1979 |
| From: | James Keppler NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION III) |
| To: | Reed C COMMONWEALTH EDISON CO. |
| References | |
| NUDOCS 7911060071 | |
| Download: ML19254F069 (1) | |
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UNITED STATES E'
'n NUCLEAR REGULATORY COMMISSION
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E REGION lli 0
8 799 ROOSEVELT ROAD
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GLEN ELLYN. 8LLINOIS 60137 4
Docket No. 50-295 Docket No. 50-304 OL: a N3 Commonwealth Edison Company ATTN:
Mr. Cordell Reed Manager of Nuclear Operations Post Office Box 767 Chicago, IL 60690 Gentlemen:
The enclosed IE Bulletin No. 79-17, Revision 1 is forwarded to you for action. A written response is required.
If you desire additional information regarding this matter, please contact this office.
Sincerely,
- h. 0
['ames G. Kepp1'er u Director
Enclosure:
IE Bulletin No. 79-17, Revision I cc w/ encl:
Mr. D. L. Peoples, Director of Nuclear Licensing Mr. N. Wandke, Plant Superintendent Central Files Director, NRR/DPM Director, NP.R/ DOR PDR Local PDR NSIC TIC Mr. Dean Hansell, Office of Assistant Attorney General 1291 110 7011060 07{
UNITED STATES 551NS No.
6820 NUCLEAR REGULATORY COMMISSION Accession No.
OFFICE OF INSPECTION AND ENFORCEMENT 79082201$7 WASHINGTON, D.C.
20555 j
October 29, 1979 IE Bulletin No. 79-17 Revision 1
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PIPE CRACKS IN STAGNANT BORATED WATER SYSTEMS AT PWR PLANTS C.scription of Circumstances:
IE Bul atin No. 79-17, issued July 26, 1979, experienced to date in safety-related stainless steel piping systems at PWRprov 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 c. Item 2, particularly the ultrasonic examination, may be inipractical 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 li:ensees 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 number of cracking incidents have been experienced in safety-related stainless steel piping systems and por-tions of systems which contain oxygenated, stagnar.t or essentially stagnant bor-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 oxygen 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 1 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 resul 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 jcint from the spent fuel cooling s stem.
R1 - Identifies those additions or rev DUPLICATE DOCUMENT j}gj
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Ent!re document Previously entered into system under. g ANO of pagesi s N o. ._.q..---.
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~ 3' 3 h P 6 November 26, 1976 II Circular No. 76-06 STRESS CORROSICS CRACK.S IN STACNANT, i s PRESSURE STAIXLISS PIPlNG CONTAINING BORIC ACID SOLUTION AT PVR's DESCRIPTION OF CIRCD1 STANCES: [ During the period November 7,1974 to November 1,1975, ceveral incidents of through-vall cratking have occurred in the 10-inch, schedule 10 type 304 scal.nless steel piping of the Reactor Building Spray and Decay Ees,t Re= ova 3 Systems at Arkansas Nuclear Plant No. 1. On October 7,1976, Virginia Electric and Power also reported through-vall cratking in the 10-inch schedule 40 type 30!. stainless dischar:p piping of the "A" recirculation spray heat exchanger at Surry Unit No. 2. A recent inspection of Unit 1 Containment Reef.rculatiot. Spray Piping revealed cracking zinilar to Unit 2. On o cober 8,1976, another incident of similar cracking in 8-inch schedule 10 type 304 stainless piping of the S-fety injection Pump Suction Line te the Cinna facility vah reported by the licensee. Infort.ation received on the metallurgical analysis conducted to date indicates that tbc failures were the result of intergranular stress corrosir.,n crackh g that initiated on the inside of the piping. /, coc:::nolicy ef facters observed associated with the corrosion =etht:.is2 were: 1. The cracks were adjacent to and propagated along weld zoner of the thin-valled low pressure piping, not part of the reactor coolant system. 2. Cracking occurred in piping containing relatively stagnant hori: acid solution tot required for normal operating conditions. 3. Analysis of surface produ.:ts at this time indicate a, chloride ion interaction with oxide formation in the relatively stagnant boric acid solution as the probable corrodant, with the state of stress probably due to velding and/or fabrication, The source of the chloride ion is tot dafinitely knova. Bovaver,,et ANO-1 the chlorides and sulfide lavel observed in the surface tr.:r.ish film near velds is bal.ieved to have been introduced into the piping during testing of the sodium thiosulfate discharge valvet, or valve leakage. Si=ilarly, at Cinna the chlorides and poteatial cryget ~ lgl g DUPLICATE DOCUMENT Entire document previously entered into system under: 7 73/ 3h ANO No. of pages: .}}