ML20135G405

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Notifies of Mod to Helium Circulator Auxiliary Sys to Mitigate Pcrv Moisture Ingress.Digital Test Valve Removed from Main Drain Sys & Will Not Be Reinstalled
ML20135G405
Person / Time
Site: Fort Saint Vrain Xcel Energy icon.png
Issue date: 09/04/1985
From: Warembourg D
PUBLIC SERVICE CO. OF COLORADO
To: Hunter D
NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION IV)
References
P-85285, TAC-59936, NUDOCS 8509180541
Download: ML20135G405 (2)


Text

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2420 West 26th Avenue, Suite 1000, Denver, Colorado 80211 September 4, 1985 Fort St. Vrain Unit No.1 P-85285 Regional Administrator "

Region IV i U.S. Nuclear Regulatory Comission SEP I ?. E 611 Ryan Plaza Drive Suite 1000 Arlington, Texas 76011 .

Attention: Mr. Dorvin Hunter Docket No. 50-267

SUBJECT:

Modification Concerning Moisture Ingress

REFERENCE:

PSC Letter, 0. R. Lee to E. H. Johnson, dated 3/12/85 (P-85082)

Dear Mr. Hunter:

Attachment 3 of the referenced letter provided a brief description of helium circulator auxiliary system modifications designed to mitigate PCRV moisture ingress. This letter provides notification of a change to one of those modifications. The test valve referred to as a Digital valve in the attachment has been removed from the 'A' circulator main drain system and will not be reinstalled at this time. The original conventional globe valve has been reinstalled and will be in operation for plant restart.

The test valve in the 'A' circulator and electronic controls on all

^ four circulator positions were installed and limited performance testing completed prior to startup. The electronic control in conjunction with controlling main drain strictly by the main drain to buffer helitm pressure differential has provided a significant system response improvement for the conventional globe valves. Performance of the test valve was found to be very satisfactory in the area of response. However, after only thirty days operation, it developed significant mechanical problems which indicated a disappointingly short service life. The test valve was, therefore, removed for evaluation by the valve manufacturer and possible reliability testing.

dh 8509180541 850904 PDR ADOCK 05000267 @d[ p P PDR ,p.m 04")p y

Should you desire further clarification of this issue, please contact Mr. M. H. Holmes at (303) 571-8409.

Very truly yours, A0$*/YLuntAW D. W. Warembourg, Manager Nuclear Engineering Division DW/ELh/deh

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