ML20102A675

Clarifies App D,Tmi Item Ii.K 3.18, Automatic Depressurization Sys Actuation Logic, (SER Confirmatory Issue 28).ADS Initiates on Low Reactor Pressure Vessel Water Level Signal Alone When Bypass Timer & 105 Timer Out

ML20102A675
Person / Time
Site:	Clinton
Issue date:	02/01/1985
From:	Spangenberg F ILLINOIS POWER CO.
To:	Schwencer A Office of Nuclear Reactor Regulation
References
TASK-2.K.3.18, TASK-TM U-0791, U-791, NUDOCS 8502080507
Download: ML20102A675 (2)

Text

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U-0791 P04-85(02-01)-L i- N33-85(02-01)-L ILLINDIS POWER 00MPANY IP CLINTON PCmER STATION. P.O. BOX 678. CLINTON. ILLINOIS 61727 February 1, 1985 o

Docket No. 50-461 Director of Nuclear Reactor Regulation

. Attention: Mr. A. Schwencer, Chief

~ Licensing Branch No. 2'

. Division of Licensing.

U.' S. Nuclear Regulatory Comission ,

Washington, D. C. 20555

Subject:

Clinton Power Station (CPS) Unit 1 Autmatic Depressurization System Actuation logic

-(SER Confirmatory Issue # 28)

Dear Mr. Schwencer:

This is in response to a request fr m the NRC Staff regarding clarification of Appendix D, IMI Action Plan Its II.K.3.18 of the

~C linton Power Station (CPS) Final Safety Analysis Report (FSAR).

The following clarifies our response to Its II.K.3.18. The high drywell pressure portion of the logic-circuit is bypassed and the

. Automatic Depressurization System (ADS) initiates on the low reactor ressure vessel (RPV) water level (Irvel 1) signal alone, when the

- p' bypass" timer and the 105 second timer are out. A time delay of six udnutes for the high drywell pressure bypass logic was chosen,

. consistent with the calculated analytic limit. The detailed analysis performed was based upon:

1. Avoidance of excessive fuel cladding heatup using 10CER50 Appendix K models and the most limiting transient as described in Figure 6.3-72 of the CPS FSAR Section 6.3.3 (assm es no operator action).

2. Providing sufficient time to allow recovery of the RPV water level above level 1 during an ATWS event.

Following receipt of level 1 signal and.once the bypass timer and the system level timer times out, the ADS initiation is sealed in and h ' the system does not automatically reset. For additional information see CPS FSAR Section 7.3.1.1.1.4.

M 8502080507 850201 /

1 PDR ADOCK 05000461 y E PDR;_ -

godt ilo r

. . U-0791 P04-85(02-01)-L N33-85(02-01)-L 1A.120 It is our understanding that the above information provides the clarification requested by the NRC Staff regarding TMI Item II.K.3.18.

required to close SER Confirmntory Issue # 28. The CPS FSAR Appendix D will be revised to reflect the above clarification.

Sincerely yours,

(:

V F. A. Sp enb'rg )

Director Nuc ear Licensing and Configuration Nuclear Station Engineering TIE /ls cc: B. L. Siegel, NRC Clinton Licensing Project Manager NRC Resident Office Regional Administrator, Region III USNRC Illinois Department of Nuclear Safety m -- -