ML20127K137

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Discusses Insp of 10 Bottom Longitudinal Tendon End Caps. Tendons Visually & Magnetic Particle Inspected for Evidence of Corrosion,Concavity,Water,Apparent Failures & Cracking.No Raised Buttonheads Found.All Tests Negative
ML20127K137
Person / Time
Site: Fort Saint Vrain Xcel Energy icon.png
Issue date: 06/07/1985
From: Warembourg D
PUBLIC SERVICE CO. OF COLORADO
To: Johnson E
NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION IV)
References
IEIN-85-10, P-85193, TAC-54639, NUDOCS 8506270277
Download: ML20127K137 (2)


Text

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h PublicService .iio s.,*.

Company of Colorado 16805 WCR 19 1/2, Platteville, Colorado 80651 June 7, 1985 Fort St. Vrain Unit No. 1 P-85193 Regional Administrator Region IV U. S. Nuclear Regulatory Commission ff,3 j

ggggg 611 Ryan Plaza Drive, Seite 1000 /I Arlington, Texas 76011 6 M l 8E Attention: Mr. Eric H. Johnson _

M Docket No. 50-267

SUBJECT:

Fort St. Vrain Additional Tendon Inspection

REFERENCES:

1) PSC Letter, D. W. Warembourg to E. H. Johnson, dated 5/~20/85 (P-85176)
2) IFE Information Notice 85-10 (G-85053)
3) I&E Information Notice 85-10 Supplement 1 (G-85098)

Dear Mr. Johnson:

As per Reference 1, ten of the bottom longitudinal tendon end caps were removed for inspection. The visual inspection consisted of examining the tendon end caps, prestressing anchor assembly stressing washer, shims, bearing plate and buttonheads for evidence of general corrosion, concavity, water or apparent failures. The inspection showed no evidence of concavity, cracking, water, or general ,

corrosion. No raised buttonheads were found during this inspection. -

To insure that there was no cracking similar to that at Farley, five y of the anchor assemblies were magnetic particle inspected for cracking. The tendons inspected were VM1, VI3, Vill, VM17, VM18, ]

VM22, VI27, VM31, VI34 and VI38. The tendons which were subjected to (6

v the examination were VM1, VM17, VM22, VM31 and VI34. #

gh 8506270277 850607 PDR ADOCK 05000267 / )b G PDR

Due to bleedout associated with liquid penetrant tests, Public Service Company considers magnetic particle testing to be more sensitive for this application. The magnetic particle tests showed-no discontinuities.

During this inspection, no visible evidence of pitting was found in the tendon caps. As per Reference 3, a galvanic cell was established at Farley between their galvanized caps and the stressing washers.

The zinc in Farley's prostressing system was essential in the establishment of the galvanic cell, which resulted in stressing washer failure. Since we have no zinc coated components associated with our prestressing system and based on all previous inspections to date, it is Public Service Company of Colorado's conclusion that Fort St. Vrain'is not susceptible nor exhibiting evidence of zinc related ,

galvanic cell corrosion.

If you have any further questions, please do not hesitate to contact Mr. M. H. Holmes at (303) 571-8409.

Very truly yours, D. rv. rviAm9 D. W. Warembourg, Manager, Nuclear Engineering Division

  • Ref. Corrosion Engineering by Fontana/Greene, 1978.

DWW/MJF/ksc Attachments

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