ML19296C168
| ML19296C168 | |
| Person / Time | |
|---|---|
| Site: | Wolf Creek  |
| Issue date: | 12/06/1979 |
| From: | Koester G KANSAS GAS & ELECTRIC CO. |
| To: | Seidle W NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION IV) |
| References | |
| NUDOCS 8002250321 | |
| Download: ML19296C168 (2) | |
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KANSAS GAS AND ELECTRIC COMPANY menacmocamsw GLENN L. KOLSTER veC E pmESIDE*eY oPEm ATIO*st December 6, 1979 Mr. W.C.
Seidle, Chief Reactor Construction and Engineering Support Branch U.S. Nuclear Regulatory Commission Region IV 611 Ryan Plaza Drive, Suite 1000 Arlington, Texas 16012 Re:
Docket No. STN 50-48?
Subj: Inspection Report 7
.t3 - Unresolved Item, Fireproofing Material on Stain-less Steel Piping. Koester ltr to Seidle dated 9/11/79 and Koester letter to Seidle dated 12/3/79.
Dear Mr. Seidle:
As reported in the above-referenced letters, investigations have been conducted by our Architect / Engineer (Bechtel) in relation to our selection of Albi Duraspray for fireproofing of structural steel. The results of these studies were reviewed with a Region IV Inspector during the week of November 26, 1979.
One portion of the investigation was an extensive survey of other fire-proofing products compared with Albi Duraspray.
Two new products were identified which can provide the required 3-hour UL fire rating and which have lower chloride content.
However, these products have other charac-teristics such as the tendency to produce dust, tendency to absorb water, low durability and low adhesion which makes them less desirable than Duraspray.
The second portion of the investigation was a study of the effects of in-advertent application of Duraspray to stainless steel piping and of pro-cedures for removal of such inadvertent applications.
This work was undertaken because, in spite of explicit requirements for masking of stain-less steel dur ing application of the fireproofing material, small quantities of Duraspray have been deposited upon stainless steel pipe. The investigation showed that there is no deleterious effect on stainless steel pipe from the r esence of Duraspray of varying times, from 1 hour1.157407e-5 days <br />2.777778e-4 hours <br />1.653439e-6 weeks <br />3.805e-7 months <br /> to 8 days.
The in-vestigation also served to cualify a removal and cleaning process which results in residual chlorides on the steel approximately equal to background chloride levels. The cleanup process has been incorporated into applicable specifications and will be subject to QA audit by KG&E.
8 0 0 2 25 03pg 201 N. Market - Wichita, Kansas - Mail Adduua: P. O. Box 208 ! Wichita. Kansas 67201 - Telephone: Area Code (316) 264-1111
1 I
Mr. W.C. Seidle December 6, 1979 Despite these precautions, your inspector has questioned the consequences of long-term contact between Duraspray and stainless steel.
The be-havior in this hypothetical situation is uncertain. There is no conclusive evidence from tests recently performed under direction of our Architect /
Engineer that any damage would occur. Power plants are in service on or near sea water and brackish water and have been subject to fairly high background levels of chlorides on stainless steel surfaces with no apparent problem of stress corrosion cracking.
On the other hand, the possibility of stress corrosion cracking can not be ruled out.
At most, only small areas of piping could be so affected.
If leaks should develop, as have developed for example in boric acid piping in operating nuclear plants, it is reasonable to expect that those leaks would be observed during periodic plant inspections and remedial actions taken at that time.
In our judgment there is no safety-related concern.
Unless new information becomes available, no further correspondence on this subject is contemplated.
Very truly yours, l
N GLK:bb