ML20137C299

Application for Amend to License NPF-11,revising Tech Spec by Changing Instrument Response Time for Main Steam Line Low Pressure Trip Function in Table 3.3.2-3 from 1 to 2 S.Fee Paid

ML20137C299
Person / Time
Site:	LaSalle
Issue date:	01/09/1986
From:	Allen C COMMONWEALTH EDISON CO.
To:	Harold Denton Office of Nuclear Reactor Regulation
Shared Package
ML20137C303	List: ML20137C299 ML20137C316
References
0892K, 892K, NUDOCS 8601160270
Download: ML20137C299 (3)

Text

'

• Commonwealth Edison -

O Oni First Nationsi Pit 2a. Chicago. Ilknois O- Address Riply to: Post Office Box 767 Chicago, lilin-ais 60690 January 9, 1986 Mr. Harold R. Denton, Director Office of Nuclear Reactor Regulation U.S. Nuclear Regulatory Comission Washington, DC 20555

Subject:

LaSalle County Station Unit 1 Proposed Amendment to Technical Specification for Facility Operating License NPF-11 Main Steam Line Low Pressure Instrument Response Time NP.C Docket No. 50-373 References (a): W. R. Butler letter to D. L. Farrar dated July 1, 1985 transmitting NRR approval of Amendment 12 to NPF-18.

(b): B. Rybak letter to H. R. Denton dated June 14, 1985.

Dear Mr. Denton:

Pursuant to 10 CFR 50.90, Comonwealth Edison proposes to amend Appendix A. Technical Specification, to Facility Operating License NPF-ll.

These changes are being submitted for your staff's review and approval.

Attachment A provides background and discussion. The proposed change is enclosed in Attachment B. The attached change has received both On-Site and Off-Site review and approval. We have reviewed this amendment request and find that no significant hazards consideration exists. Our

! review is documented in Attachment C.

r Conunonwealth Edison is notifying the State of Illinois of our i request for this amendment by transmitting a copy of this letter and its attachments to the designated State Official.

The proposed Unit 1 change revises the instrument response time for the Main Steam Line Low Pressure trip function in Table 3.3.2-3 from 1 to 2

~

1 seconds. This change has already been approved for Unit 2, when the l

Barksdale MSL low pressure switches were replaced with environmentally j

qualified SOR switches. The same modification will be performed on Unit 1 during the current refueling outage. Therefore we request approval of the attached technical specification change prior to startup for Cycle 2 at Unit i 1. This is currently scheduled for March, 1986.

~

6 f 9601160270 860109 ADOCK 05000373

'Fgl pin dey ((

PDR p PDR l/, #

. l H. R. Denton January 9, 1986 ,

l In accordance with the requirements of 10 CFR 170, a fee remittance in the amount of $150.00 is enclosed.

Please direct any questions you may have concerning this matter to this office.

Threc (3) signed originals and thirty-seven (37) copies of this transmittal and its attachments are provided for your use.

Very truly yours, C. M. Allen Nuclear Licensing Administrator im Attachments A: Background and Discussion B: Technical Specification Change to NPF-11 C. Evaluation of Significant Hazards Consideration ec: Region III Inspector - LSCS Dr. A. Bournia - NRR M. Parker - State of Ill.

SUBSCRIBED AND to bef te me this. day -

of a nuAllA- , 1986 Ofh Notaty Public {

0892K

ATTACHMENT A

SUBJECT:

LaSalle County Station Unit 1 Main Steam Line Low Pressure Response Ti me BACKGROUND The Main Steam Line (MSL) Low Pressure Switches are part of the Primary Containment Isolation System circuitry. These switches protect the Reactor Core by closing the Main Steam Isolation Valves during a depressuri-zation transient caused by a failure of the pressure regulator. The MSL low pressure switches, on Unit 1, are scheduled to be changed from the Barksdale model currently installed, to an environmentally qualified Static-0-Ring (SOR) pressure switch, during the first refuel outage. (License Condition 2.c.11)

The installation of these same SOR switches was completed on Unit 2 in June, 1985. It was observed at that time that the SOR switches could not consistently meet the Tech Spec required response time (TS Table 3.3.2.3.A.l.c.2). Commonwealth Edison requested and received an emergency Technical Specification Change for Unit 2 at that time to increase the maximum response time limit from _1 second to _2 seconds (Reference (a)).

Commonwealth Edison is now requesting that the same change be made to the Unit 1 Technical Specification.

DISCUSSION:

Commonwealth Edison replaced the Barksdale MSL low pressure switches on Unit 2 with environmentally qualified SOR switches during an outar,e in May and June 1985. The new switches were initially response time tested during May in accordance with Inctrument Maintenance Department procedure LIS-PC-17.

The switches met the response time acceptance criteria for fast ramp rates

(-25 psi /sec), however, they exceeded the acceptance criteria at slow ramp rates (-5 psi /sec).

Assistance was requested from the Commonwealth Edison Station Nuclear Engineering Department and General Electric to help determine a course of action. GE responded with a recommendation that the Tech Spec maximum response time limit for the MSL low precsure switches be increased to _2 seconds. The justification was included with the Unit 2 submittal (reference (b)).

No new nor unanalyzed safety issue results from the extension of this sensor response time to 2 seconds versus 1 second. It is a matter of allocation within the pre-analyzed envelope. The purpose of this low pressure isolation is to protect the fuel by restricting reactor operation ao pressure regimes at which the GEIL fuel correlation is beyond serious question. The use of 2 seconds for instrument response, as determined according to Tech Spec definitions, does not challenge nor violate this fuel protection criteria.

0892K