ML19247A637
| ML19247A637 | |
| Person / Time | |
|---|---|
| Site: | Peach Bottom  |
| Issue date: | 07/17/1979 |
| From: | Grier B NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION I) |
| To: | Daltroff S PECO ENERGY CO., (FORMERLY PHILADELPHIA ELECTRIC |
| References | |
| NUDOCS 7908010519 | |
| Download: ML19247A637 (1) | |
Text
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Docket Nos. 50-277 JUL 17 ms 50-278 Philpielphia Electric Company AT'ti:
Mr. S. L. Daltroff Vice President Electric Production 2301 Market Street Philadelphia, Pennsylvania 19101 Gentlemen:
This Information Notice is provided as an early notification of a possibly significant matter.
It is expected that recipients will review the information for possible applicability to their facilities.
No response is requested at this time however licensees should be aware that the NRC is evaluating the issuance of a Bulletin to operating PWR's requesting information on previous inservice inspections of stagnant borated water systems and requesting inspection of systems which have not been inspected recently.
If you have questions or comments regarding this matter, please contact the Director of the appropriate NRC Regional Office.
Sincere!v,
/o s/
c B
e H. Grier Director
Enclosures:
1.
IE Information Notice No. 79-19 2.
List of Information Notices Issued in 1979 cc w/encls:
W. T. Ullrich, Station Superintendent Troy B. Conner, Jr., Esquire Eugene J. Bradley, Esquire Raymond L. Hovis, Esquire Warren Rich, Esquire b/E27S 7 90801 dI
UNITED STATES NUCLEAR REGULATORY COMMISSION OFFICE OF INSPECTION AND ENFORCEMENT WASHINGTON, D. C.
20555 IE Infonnation Notice No. 79-19 Date:
July 17, 1979 Page 2 of 2 PIPE CRACKS IN STAGNANT BORATED WATER SYSTEMS AT PWR PLANTS Description of Circumstances:
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 portions of systems which contain oxygenated, stagnant or essentially stagnant borated 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. surface and propagating in either an intergranular or transgranular mode typical of Stress Corrosion Cracking.
Analysis indicated the probable corrodents to be chloride and oxygen contamin-ation 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 76-06 (copy attached) 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 build-up 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 performed by the licensee on a section of cracked and leaking weld joint from the spent fuel cooling system.
The conclusion of this analysis was that cracking was due to Intergranular Stress Corrosion Cracking (IGSCC) originating on the pipe I.D.
The cracking was localized to the heat affected zone where the type 304 stainless steel is sensitized (precipitated carbides) during welding.
In addition to the main through-wall crack, incipient cracks were observed at several locations in the weld heat affected zone including the weld root fusion area where a miniscule lack of fusion had occurred.
The stresses responsible for cracking are believed to be primarily residual welding stresses in as much as the calculated applied stresses were found to be less than code design limits.
There is no conclusive evidence at this time to identify those aggressive chemical species which promoted this IGSCC attack.
Further analytical efforts in this area and on other system welds is being pursued.
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ENCLOSURE 1 UNITED STATES NUCLEAR REGULATORY COMMISSION OFFICE OF INSPECTION AND ENFORCEMENT WASHINGTON, D.C.
20555 IE Circular No. 79-13 Date:
July 16, 1979 Page 1 of 1 REPLACEMENT OF DIESEL FIRE PUMP STARTING CONTACTORS Description of Circumstances:
On May 28, 1978, the Diesel Fire Pump failed to start remotely at DavisBesse, Unit 1 facility operated by Toledo Edison Company.
The cause for failure was defective starting conta: tors.
A subsequent investigation into the cause of a similar failure on January 18, 1978, at Commonwealth Edison Company's Dresden 2/3 Diesel Fire Pump identified a generic problem with Cummins Industrial Fire Pump Engines.
Discussion:
The investigation revealed that Cummins Engine Company issued a Service / Parts Topics No. 74T 133A announcing new components available for Industrial Fire Pumps (NH2201F, N855F, N855F1, NT855F2 series engines) to improve operation of inline 6 cylinder Industrial Fire Pump Engines.
In this topic, Cummins recom-mends that when replacing the 118848 magnetic switch and 199573 DC relay contactor, use the new 217588 magnetic switch.
The new design component has a 6 ampere draw whereas the old combination has approximately 3 amperes draw.
Davis Besse and Dresden sites have implemented the corrective action recommendea by Cummins.
Recommended Actions for Licensees' Consideration:
All holders of operating licenses or cor.struction permits should be aware of the potential problem of the type discussed above.
Because of the generic implications in this matter, it is recommended that both licensees of operating facilities and holders of construction permits conduct a review to determine if the above diesel fire pump engines are in use or planned for use at your facility (ies).
If these engines are in use or planned for use, determine if the Cummins type 118848 Magnetic Switch and 199573 DC relay contactors are also employed.
For those engines which have these components, develop a pro-gram for their replacement with the new 217588 Magnetic Switen.
No written response to this Circular is required.
If you require additional information regarding these matters, contact the Director of the appropriate NRC hegional Office.
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