ML20054J641

Forwards Info Re Proposed Changes to Undervoltage Relaying as Result of Studies,Replacing Info in Util . Preliminary Info Re Future Tech Spec Submittal,Scheduled for Oct 1982,also Submitted

ML20054J641
Person / Time
Site:	Fort Saint Vrain
Issue date:	06/23/1982
From:	Brey H PUBLIC SERVICE CO. OF COLORADO
To:	Kuzmycz G Office of Nuclear Reactor Regulation
References
P-82218, NUDOCS 8206290375
Download: ML20054J641 (9)

Text

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r public Service Company @ OcEnImde 5909 East 38th Avenue, Denver, Colorado 80207 8

June 23, 1982 Fort St. Vrain Unit No. 1

, P-82218 FM-G

% -257 Mr. George Kuzmycz, Project Manager Special Projects Branch Division of Project Management Office of Nuclear Reactor Regulation U. S. Nuclear Regulatory Commission Washington, D.C. 20555

SUBJECT:

Electrical Power Systems

REFERENCES:

1) P-82169 2)P-82184

Dear Mr. Kuzmycz:

The purpose of this letter is to provide information regarding proposed changes to Fort St. Vrain's undervoltage relaying as a result of our undervoltage studies.

Also included is preliminary information regarding our future technical specification submittal.

UNDERVOLTAGE RELAYING Table 1 and Figures 1 through 5 provide details concerning the proposed undervoltage relaying modifications. This infonnation replaces the information provided by Figure 4 of Attachment 3 to our letter P-82169 dated May 28, 1982.

FUTURE TECHNICAL SPECIFICATION

1. Limiting conditions for operation of the 480 volt buses will not change.

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(206290375 820623 PDR ADOCK 05000267 p PDR

P-82218 Page 2

2. Limi ting condition for operation of the 480 volt loss of voltage and degraded voltage relays will be provided. Our preliminary thoughts are to place any inoperable relay in the tripped position until repair or replacement is made.

3. Surveillance requirements are preliminarily proposed as i follows:

a) A CHANNEL CHECK will be accomplished by individually annunciating 1oss of vol tage to each undervol tage relay. Loss of voltage to the relays will automatically place them in the tripped position.

b) CHANNEL FUNCTIONAL TEST will be perfonned monthly and will consist of functionally checking each relay for dropout when voltage is removed.

4. Channel Calibration will take place during refueling outages.

5. Loss of Offsite Power Testing will be performed during refueling outages. It is preliminarily proposed that this test will accomplish the following:

a) Verify de-energization of the essential 480V busses and load shedding from the essential 480V buses.

b) Verify the diesel starts from ambient condition on the auto-start signal, energizes the 480V essential busses with permanently connected loads, energizes the auto-connected essential loads through the load sequencer and operates for greater than or equal to 5 minutes while its generator is loaded with the essential loads, c) Verify that on trip of both diesel generators, the loads are shed from the essential busses and the diesels restart on the auto-start signal, the essential busses are energized with pemanently connected loads, the auto-connected essential loads are energized through the load sequencer and the diesels operate for greater than or equal to 5 minutes while its generators are loaded with the essential loads.

d) Verify that all undervoltage relays operated.

Unless you require additional infonnation, the above concludes our responses to the NRC staff's undervoltage questions regarding Fort St. Vrain.

. P-82218 Page 3 As we indicated in our letter P-82169 dated May 28, 1982, a finalized technical specification will be forwarded during October 1982.

If you have any questions, please call.

Very truly yours, d.w o w h H. L. Brey, Manag r Nuclear Engineering Division HLB / MEN:pa Attachments r$

, ,- Attachment to P-82218 TABLE 1 480V UNDERVOLATAGE RELAYS DEGRADED VOLTAGE Trip Value Allowable Value Type Function 104V + SV 99V - 109V ITE 27H Trip Bus Involved 120 Sec j; 5% 114 Sec - 126 Sec AGASTAT .- See Figure 1 LOSS OF VOLTAGE Trip Value Allowable Value Type Function 93V.+ 3%

90V - 95.8V WESTINGHOUSE CV2 480V ATO Time Dial = 5 See Figure 2 82V + 3%

79.5V - 84.5V WESTINGHOUSE CV2 Diesel START Time Dial = 6 Load Shed See Figure 3 72V + 5% 68.4V - 75.6V ITE 27H Rx SCRAM 30 Sec j; 5% 28.5 Sec - 31.5 Sec AGASTAT See Figure 4 um

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