ML20069J315

Application for Amend to License DPR-29,changing Safety Relief Actuating Setpoint of Target Rock Valve to 1,135 Psig & Changing Setpoint of Two Electromatic Relief Valves to 1,115 Psig

ML20069J315
Person / Time
Site:	Quad Cities
Issue date:	10/18/1982
From:	Rausch T COMMONWEALTH EDISON CO.
To:	Harold Denton Office of Nuclear Reactor Regulation
Shared Package
ML20069J320	List: ML20069J315 ML20069J364
References
5260N, NUDOCS 8210250114
Download: ML20069J315 (3)

Text

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s Convronwealth Edison j ~ one First Natiortal Plats. Chcago.pnoys i ) Address Rep:y to: Post Othc3 Box 767

/ Chicago Ilknois 60690 October 18, 1982 14r . Harold R. Denton, Director Office of Nuclear Reactor Regulation U.S. Nuclear Regulatory Commission Washington, D.C. 20555 Subjec t : Quad Cities Station Unit 1 Proposed Technical Specification Change Concerning Safety /Related Valve Setpoints NRC Do cket - No . 50-254 -

Dear Mr. Denton:

Pursuant to 10 CFR 50.59, Commonwealth Edison proposes to amend the Appendix A Technical Specifications to Facility Operating License DPR-29 for Quad Cities Station Unit 1. The requested amend-ment changes the safety / relief actuating setpoint of the Target Rock valve to 1135 psig and changes the setpoint of two Electromatic Relief (EMR) valves to 1115 psig.

In analyses associated with the Mark I Containment Program, it was discovered that excessive loads could be subjected to the torus if a relief valve actuation occurs shortly a f ter it closes.

This loading is the result of a water leg entrapped in the relief valve discharge line from the vacuum caused by the condensed steam in this line. To prevent such loading, a modification to the EMR valve logic is currently being installed which will delay automatic opening of two EMR valves up to ten seconds from the last closure of i the valve. In order to maintain very similar overall Target Rock cnd EMR valve performance with this logic change and prevent exces-Give loading, the two af fected (EMR) valves Techical Specification pressure setpoints must be lowered so that they are the first to actuate and the setpoint of one valve (Target Rock) will be raised.

General Electric has evaluated this modification and has

determined that it will have an insignificant impact on transient end ECCS evaluations

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H. R. Denton October 18, 1982 Transients For the limiting transient (Load Rejection w/o Bypass) the pressurization is estimated to be milder because there is a net relief valve setpoint decrease, thus _slightly lowering the peak pressure and power for the transient. This change is expected to have no impact on the increased subcooling events.

Overpressure The ASME overpressurization event (no credit for EMR valve actuation) is estimated to have a slightly increased peak pressure (no more than 5 psi) because the Target Rock Safety /

Relief valve setpoint is slightly increased. This peak pressure increase is insignificant compared to the calculated margin for QC 1 Cycle 7 (about 50. psi margin to peak vessel allowable pressure of 1375 psig).

ECCS No impact is expected on the PCT for the limiting break (i.e.

large break LOCA). The impact on the worst case small break LOCA). The impact on the worst case small break LOC A is expected to be less than + 20 0F. This increase is not significant, and cannot make the SBLOC A more limiting than the LBLOCA. Also, the ten second delay is not expected to have any impact on peak pressure as the steam generation is much reducted after the seram.

Although the net e ffect on transients and accidents is insignificant for the reasons described above, future cycle specific reload analyses will explicitly account for the actual setpoints in place. Because these changes do not affect the design basis LOCA (large break), no explicit ECCS reanalyses are necessary.

The attached changes have received On-Site and Of f-Site review and approval. Installation of this modification is required in the current Unit 1 outage by the Mark I orders; your approval of this request is therefore necessary prior to startup (early December 1982).

We have determined that this request is a Class III 10 CFR 170 amendment request. As such, a fee remittance of $4,000 is i Gnclosed.

Please direct any questions you may have concerning this )

catter to this office.  !

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H. R . Denton October 18, 1982 Three (3) signed originals and thirty-seven (37) copies of this transmittal are provided for your use.

Very truly yours,

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Thoma s J. Rausch Nuclear Licensing Administrator 1m Attachment cc: Region III Inspector - Quad Cities SUBSCRIBED and SWORN to before me this -/f ~

day of M M J , 1982

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