ML19332A541

Requests Relief from LCO 4.3.10 for 60 Days,After Return to Power,To Check & Readjust Hangers & Snubbers for Main Steam & Cold & Hot Reheat Lines.Many Hangers Will Require New Position Settings Which Must Be Made at Full Steam

ML19332A541
Person / Time
Site:	Fort Saint Vrain
Issue date:	09/08/1980
From:	Warembourg D PUBLIC SERVICE CO. OF COLORADO
To:	Kuzmycz G Office of Nuclear Reactor Regulation
References
P-80304, NUDOCS 8009160364
Download: ML19332A541 (2)

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.t 50-0 67 public service company ce cancMe September 8, 1980 Fort St. Vrain -

Unit No. 1 P-80304 Mr. George Kuzmycz, Project Kanager U. S. Nuclear Regulatory Commission Division Project Management Special Projects Washington, D. C. 20555

SUBJECT:

Fort St. Vrain Unit No. 1 Technical Specification Relief LC0 4.3.10

Dear Mr. Kuzmyc:

Just prior to our scheduled maintenance shutdown we discovered that nine (9) of our hydraulic oil snubbers on the main steam line had bottomed out due to thermal growth of the main steam line. We entered into LCO 4.3.10 and were unable to correct the problem within the 72 hour8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br /> time allowed by LCO 4.3.10 which forced us to shutdown one day earlier than planned.

Investigation of the problem revealed that our constant support hangers (spring hangers) were not prcperly adjusted for the hot position, and consequently these hangers wre not carrying the appropriate load in the hot position which in turn affected the stroke position of various hydraulic snubbers.

During the 72 hour8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br /> period of LCO 4.3.10 we were able to check and record the position of the snubbers and the constant support hangers and we have now been able to check the cold position of hangers and snubbers. It appears that many of the nangers will require new position settings, but the settings must be made at full steam conditions.

The nine snubbers which caused the original problems will be adjusted and restroked during our present outage; however, we expect that many of the other snubbers may be affected when we begin readjustment of the hot settings for the constant suoport hangars upon return to power operations. Due to the number of hangers involved it will be impossible to effect all necessary hanger adjustments within 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br /> allowed by LCO 4.3.10, and at the same time we must have full steam conditions in order to make the adjustments. The two situations are not compatible.

We are requesting, therefore, relief from LCO 4.3.10 for a period of N 60 days following return to power after the present outage. This .5

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[ relief will allow time tol check and' readjustias necessary_the-hangers

and snubbers for the main ^ steam,. cold reheat, and hot reheat lines.

We willL plan our work. so that no more than -15% of snubbers on a given

line (i.e. 13 main steam snubbers, 9 hot reheat snubbers, or 9 cold

. reheat-snubbers) are inoperable.at-any given time. Should.the number of inoperable snubbers increase beyond these limits ~during the 60 day

. relief -period we would apply the provisions of LCO 4.3.10 until the number-of, inoperable snubbers could be returned to a number less than

. the 15%. _ Keeping the ' number. of inoperable snubbers to a minimum

- coupled with_the low probability-of seismic events should ensure safe

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operation of the unit during~ the sixty (60) day period.

Your immediate attention -to this request will be appreciated as we are presently _ scheduled ;to return to po'wer operation beginning September 22, 1980.

Very truly yours WW Don W. Warembourg Manager, Nuclear Production Fort St. Vrain Nuclear Generating Station DWW/dkm

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