ML19254F064
| ML19254F064 | |
| Person / Time | |
|---|---|
| Site: | Wolf Creek  |
| Issue date: | 10/29/1979 |
| From: | Seyfrit K NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION IV) |
| To: | Koester G KANSAS GAS & ELECTRIC CO. |
| References | |
| NUDOCS 7911060042 | |
| Download: ML19254F064 (1) | |
Text
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o UNITED STATES
/pRREc,%,,
NUCLEAR REGULATORY COMMISSION
[S REGION IV n
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611 RY AN PL AZA DRIVE, SUITE 1000 3U
- E j ARi.INGTON, TEXAS 76012 f
'%,n October 29, 1979 In Reply Refer To:
RIV Docket No.
STN 50-482/IE Bulletin No. 79-17, Revision 1 Kansas Gas & Electric Co.
Attn:
Mr. Glenn L. Koester Vice President-Operations Post Office Box 208 Wichita, Kansas 67201 Gentlemen:
The enclosed IE Bulletin No. 79-17, Revision 1 is forwarded to you for information. No written response is required. However, the potential corrosion behavior of safety-related systems as it regards your plant over the long term shoulu be taken into consideration. If you desire additional information concerning this matter, please contact this office.
Sincerely, f.?
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/lLk Karl V. SeyfrM Director
Enclosures:
1.
IE Bulletin No. 79-17, Revision 1 2.
List of IE Bulletins Issued in Last Six Months cc: w/ enclosures Messrs. Nicholas A. Petrick, SNUPPS D. T. McPhee, Kansas City Power and Light Company Gerald Charnoff, Shaw, Pittman, Potts & Trowbridge E. W. Creel, Kansas Gas and Electric Company 12 2 083 1900 G77 0 60 0 0 g 911
UNITED STATES SSINS No.: 6820 NUCLEAR REGULATORY COMMISSION Accession No.:
OFFICE OF INSPECTION AND ENFORCEMENT 79082201)7 WASHINGTON, D.C.
20555
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IE Bulletin No. 79-17 Revision 1 Date: October 29, 1979 Page 1 of 5 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 cracking 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 El inspection agencies it has beea determined the the requirements of Item 2, R1 particularly the ultrasonic examination, may be impractical because of R1 unavailabil#.ty of qualified personnel in certain cases to complete the R1 inspections within the time specified by the Bulletin.
To allevitte this R1 situatior. and allow licensees the resources of improved ultrasonic inspection R1 capabilities, a time extension and clarificaticas to the bullet *n have been R1 made. 7hese are referenced to the affected items of the origiaal bulletin.
During the period of November 1974 to February 1977 a number of cracking incidents have eeen experienced in safety-related stainless steel piping syste-s 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 zone cf 8-inch to 10-inch type 304 material (schedule 10 and 40), initiating on the 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 vice of the apparent generic nature of the problem.
During the rsfueling outage of Three Mile Island Unit I which began in Febrt.ary of this yeai; visual inspections disclosed five (5) through-wall cracks at welds in the spent fuel coo:ing system p' ping and one (1) at a weld in the decay heat removal system. These cracks were found as a and later confirmed by liquid penetra cracking was reported to the NRC in a 1979. A preliminary metallurgical an DUPLICATE DOCUMFFT aection of cracked and leaking weld j Entire document previously j ")C)2 084 enterea.nte system under:
7,,9a_ re_ c,o,/37, R1 - Identifies those additions or rev ANO g r) O n74 No. of pages:
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IE Circular 76-06 November 24, 1976 t
STRESS CORROSION CPaCKS IN STAGNANT, LOU PRESSURE STAINLESS PIPING CONIAINING EORIC ACID SOLUTION AT PUR's DESCRIPTION OF CIRCUMSTANCES:
During the period November 7,1974, to November 1,1975, ceveral inci-dents of through-wall cracking have occurred in the 10-inch, schedule, * '
10 type 304 stainless steel piping of the Reactor Building Spray and Decay Heat Systens at Arkansas Nuclear Plant No. 1.
On October 7,1976, Virginia Elcetric and Power also reported through-vall cracking in the 10-inch schedule 40 type 304 stainless discharge piping of the "A" recirculation spray heat exchanger at Surry Unit No. 2.
A recent inspection of Unit No. 1 Containment Recirculation Spray Piping revealed cracking similar to Unit No. 2.
On October 8,1976, another incident of similar cracking in 8-inch sched-61e 10 type 304 stainless pf ping of the Safety Injection Pump Suction Line at the Ginna facility was reported by the licensee.
Information received on the metallurgical analysis conducted to date indicates that the. failures were the result of intergranular stress corrosion crdelfing"that initiated on the inside of the piping. A
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co:rnonality of f actors observed associated with the corrosion mechanism were:
1.
The cracks were adjacent to and propagated along ueld zones of the thin-valled low pre.sure piping, not part of the reactor coolant
. system.
2.
Cracking occurred in piping containing relatively stagnant boric acid solution not required for norcal operating conditions.
3.
Analysis of surface products at this time indicate a chloride ion interaction with oxide forcation in the relatively stagnant boric acid solution as the probabic corrodant, with the state of stress probably due to velding and/or fabrication.
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( s ANo 79@736256 No. of pages:
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