ML20204E561

Forwards Supplemental Response to 860507 Request for Addl Info Re Steam Line Rupture Detection/Isolation Sys.Listed Surveillance & Testing Requirements Will Verify Sys Operability

ML20204E561
Person / Time
Site:	Fort Saint Vrain
Issue date:	07/25/1986
From:	Warembourg D PUBLIC SERVICE CO. OF COLORADO
To:	Berkow H Office of Nuclear Reactor Regulation
References
P-86478, TAC-60421, NUDOCS 8608010134
Download: ML20204E561 (4)

Text

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OPublic Service ~

2420 W. 26th Avenue, Suite 1000, Denver, Colorado 80211 Company of Colorado July 25, 1986 Fort St. Vrain Unit No. 1 P-86478 Director of Nuclear Reactor Regulation U.S. Nuclear Regulatory Commission Washington, DC 20555 Attn: Mr. H. N. Berkow, Director Standardization and Special Projects Directorate Docket No. 50-267

SUBJECT:

Fort St. Vrain Equipment Qualification - SLRDIS

REFERENCES:

1) PSC Letter, Warembourg to Berkow, dated June 10, 1986 (P-86417)

2) NRC Letter, Heitner to Walker, dated May 7, 1986 (G-86246)

Dear Mr. Berkow:

Public Service Company of Colorado (PSC) submitted, in Reference 1, additional information on the Steam Line Rupture Detection / Isolation System (SLRDIS). The letter provided PSC's response to nine (9) of the ten (10) NRC staff questions in Reference 2.

l The attachment to this letter provides PSC's response to the remaining NRC question (No. 2) on SLRDIS.

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- P-86478 Page 2 July 25, 1985 Should you have any questions concerning this matter, please contact Mr. M. H. Holmes at (303) 480-6960.

Very truly yours,

<h /Y- lWu&

D. W. Warembourg, Wanager Nuclear Engineering Division DWW/JS:pa Attachment l

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. e ATTACHMENT TO P-86478

. Attachment to P-86478 NRC Question

2. Discuss your plans to verify continued satisfactory operation of the SLRDIS after initial installation including your proposal to conduct periodic systematic tests of the SLRDIS in place. This niscussion should include the Technical Specification modifications you plan to provide to accomplish periodic, in situ testing. Discuss how you intend to verify the SLRDIS response time assumed in the safety analyses.

Response

Table 5.4-3 of the amended Technical Specification provided in PSC letter, Walker to Berkow, dated June 4, 1986 (P-86227),

includes the surveillance requirements for the Steam Line Rupture Detection Isolation System (SLRDIS). The setpoint for the low level pre-trip alarm will be periodically verified in addition to these requirements. The Safe Shutdown Cooling Power Operated Valve Test Procedures (SR-5.3.4bl-A and SR-5.3.4b2-A) to meet Technical Specification requirements will be revised such that an operability test will be performed on all valves actuated by SLRDIS in addition to the existing safe shutdown cooling valves tested by these procedures. These procedurc. include verification of valve stroke times.

Design verification of the detection rack response time assumption used in the safety analysis will be performed during the initial functional test by providing a simulated rate-of-rise signal to the rack input and recording the difference in time between application of 55 degrees F./ min. rate-of-rise and output contact operation. No periodic response time testing will be performed on the detection rack since the response time of the detection rack is directly related to the system clock frequency of the rack, due to the microprocessor based technology used in the rack. This clock frequency will be checked annually as part of the Technical Specification requirements. Design verification of the thermistor cable response time was performed by Factory Mutual Research Corporation. This information was provided as requested in PSC letter, Warembourg to Berkow, dated June 10, 1986 (P-86417), response to NRC question number 4.

PSC concludes that the above surveillance and testing requirements will verify the SLRDIS system operability and response time to initiate protective actions to mitigate the consequences of a HELB.