ML19323B147

From kanterella
Jump to navigation Jump to search
Forwards Response to Item 2.b of IE Bulletin 79-17,Revision 1, Pipe Cracks in Stagnant Borated Water Sys at PWR Plants. No Intergranular Stress Corrosion Cracking Is Present in Sys at Facility
ML19323B147
Person / Time
Site: Fort Calhoun Omaha Public Power District icon.png
Issue date: 03/26/1980
From: William Jones
OMAHA PUBLIC POWER DISTRICT
To: Seyfrit K
NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION IV)
References
IEB-79-17, NUDOCS 8005120013
Download: ML19323B147 (2)


Text

-_ . _ _ - _ _ _

e, 80 0512 0Od Q bec to DAC:ADM:

CENTRAL F1LES PDR:HQ 2  % NSIC Omaha Public Power District .

STATE 1623 HARNEY e Q M A H A. NESRASMA 68102 e TELEPHONE 536-4000 AREA CODE 402 March 26, 1980 Mr. K. V. Seyfrit, Director U. S. Nuclear Regulatory Comission Office of Inspection and Enforcement Region IV 611 Ryan Plaza Drive Suite 1000 Arlington, Texas 76011

Reference:

Docket No. 50-285

Dear Mr. Seyfrit:

The Omaha Public Power District received IE Bulletin 79-17, Revision 1, requesting information on stress corrosion cracking of safety related piping containing stagnant, oxygenated, borated water. In response to item 2.b of the bulletin, the District has conducted inspections of this piping and the results are forwarded herewith.

The actions required by items 1 and 2.a of IE Bulletin 79-17, Revision 1, are complete as reported in the District's letter dated November 28, 1979.

Sincerely, W.C./ Jones Division Manager Production Operations WCJ/KJM/BJH/TLP:jmm Attach.

cc: 0IE, Washington LeBoeuf, Lamb, Leiby & MacRae e" 4.'~i~T/7 6; g -

,;, 7- i.Zl. b.b_, j

.m, ..

.I APR - 31980 . i:.

OI .

RESPONSE TO IE BULLETIN 79-17, REVISION 1 PIPE CRACKS IN STAGNANT, 0XYGENATED, B0 RATED SYSTEMS AT PWR PLANTS The inspections of item 2.b in IE Bulletin 79-17, Revision 1, have been completed. The systems inspected which include all safety related piping containing oxygenated, stagnant, borated water are:

(1) the Emergency Core Cooling System, (2) the Containment Spray System, and (3) the Shutdown Cooling System.

A total of 10.6% of all welds in the three systems were inspected, such that no one system had less than 10% of its welds inspected. All piping in these systems is austenitic stainless steel. An unbiased mixture of pipe diameters and wall thickness distributed among both horizontal and vertical runs were inspected, following the criteria described below.

Welds in piping with a wall thickness of less than or equal to 0.250" were examined by OPPD personnel using both visual and liquid penetrant (surface) methods. All other welds were volumetrically analyzed by Southwest Research Institute (SwRI) personnel using ultra-sonic testing (UT) techniques.

The UT methods employed by SwRI personnel have a demonstrated ability to detect stress corrosion cracking. The liquid penetrant technique is also a capable way of finding stress corrosion cracking in thinner walled piping. No reportable UT indications and no apparent  ;

liquid penetrant testing defects were observed. I l

It is therefore concluded.that in the stagnant, oxygenated, borated systems at Fort Calhoun Station Unit No.1, no intergranula" stress corrosion cracking is present and continued operation of the systems is justi fied.

l 1

_ _ _