ML19254F071
| ML19254F071 | |
| Person / Time | |
|---|---|
| Site: | Perry  |
| Issue date: | 10/29/1979 |
| From: | James Keppler NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION III) |
| To: | Davidson D CLEVELAND ELECTRIC ILLUMINATING CO. |
| References | |
| NUDOCS 7911060082 | |
| Download: ML19254F071 (1) | |
Text
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UNITED STATES
'j NUCLEAR REGULATORY COMMISSION
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REGION lli
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799 ROOSEVELT ROAD o
e' GLEN E LLYN. lLLINOIS 60137 Docket No. 50-440 Docket No. 50-441 The Cleveland Electric Illuminating Company ATTN:
Mr. Dalwyn R. Davidson Vice President - Engineering P. O. Box 5000 Cleveland, OH 44101 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,
%20f*
famesG.Kep,"lTr p
Director
Enclosure:
IE Bulletin No. 79-17, Revision 1 cc w/ encl:
Central Files Director, NRR/DPM Director, NRR/ DOR PDR Local PDR NSIC TIC Harold W. Kohn, Power Siting Commission kt l2'/i j4s
'011060082
UNITED STATES SSINS No.
6820 NUCLEAR REGULATORY COMMISSION Accession No.
OFFICE OF INSPECTION AND ENFORCEMENT 79082201)7 WASHINGTON, D.C.
20555 3
October 29, 1979 IE Bulletin No. 79-17 Revision 1 s'
s PIPE CRACKS IN STAGNANT B0 RATED WATER SYSTEMS AT PWR PLANTS Description of Circumstances:
IE Bulletin No. 79-17, issued July 26, 1979, provided information on the tracking R1 experienced to date in safety-related stainless steel piping systems at PWR R1 plants.
Certain actions were required of all PWR facilities with an operating R1 license within a specified 90-day time frame.
R1 After several discussions with licensee owner group representatives and inspection R1 agencies it has been determined that the requirements of Item 2, particularly R1 the ultrasonic examination, may be impractical because of unavailability of R1 qualified personnel in certain cases to complete the inspections within the time R1 specified by the Bulletin.
To alleviate this situation and allow licensees the R1 resources of improved ultrasonic inspection capabilities, a time extension and R1 clarifications to the bulletin have been made.
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, stagnant or essentially stagnant bor-ated water.
Metallurgical investigations revealed these cracks occurred in the weld heat affected zane of 8-inch to 10-inch type 304 material (schedule 10 and 40), initiating on tM piping I.D. surface 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.
The NRC issued Circular No. 76-06 (copy enclosed) in view of the apparent generic nature of the problem.
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.
These cracks were found as a result of local boric acid tailuap and later confirmed by liquid penetrant tests.
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 perfortred by the licensee on a section of cracked and leaking weld joint from the spent fu R1 - Identifies those additions or rev DUPLICATE DOCUMENT Entire accument previously entered into system under.
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No. or vases:
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b November 26, 1976 IE Circular No. 76-06 STRESS CORROSION CRACyd IN STAGNANT, LOW PRESSURE STAINLESS PIPING CONTAINING BORIC ACID SOLUTION AT PWR's DESCRIPTION OT CIRCD1 STANCES:
q During the period November 7,1974 to November 1,1975, ceveral incidents of through-vall cracking have occurred in the 10-inch, schedule 10 type 304 stainless stael piping of the Reactor Building Spray and Decay East
~
Re= ova) Syster.s at Arkansas Nuclear Plant No. 1.
On October 7,1976, Virginia Electric and Power also repcrted through-
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wall cracking in the 10-inch schedule 40 type 30!. stainless discharge piping of the "A" recirculation spray heat exchanger a: Surry Unit No. 2.
A recent inspection of Unit 1 Containment Recirculation Spray Piping revealed cracking similar to Unit 2.
On October 8,1976, another incident of similer cracking in 8-1=:h schedule 10 type 3Cf. stainless piping of the Srfety injection Punp Suction Line st the Cinna facility was reported by the licensee.
Infomation received on the netallurgical analysis conducted to date indicates that the f ailures were the result of intergrenular stress corrosion cracking that initiated on the inside of the piping.
A cc==:nclity of f acters observed associated with the corrosion =ethr.:.isz were:
1.
The cracks were adjacent to and propagated along veld zones of the thin-valled lov pressure piping, not part of the reactor coolant system.
2.
Cracking occurred in piping containing relatively stagnant bori:
acid solution tot required for normal operating conditions.
3.
Analysis of surface products at this P.
indicate a chloride ion interaction with oxide forr.ation in
.elatively stagnant -boric acid solution as the probable corrodtat, with the state of stress probably due to velding and/or fabrication.
The source of :he chloride ion is not dafinitely knovn.
Bovaver,,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 so/.tum thiosulfate discharge valves, or valve leakage.
Si=ilarly, at Gs.nna the chlorides and potential oxygte DUPLICATE DOCUMENT Entire document previously entered into system under:
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