ML20135A534

Supplemental Application for Amend to Licenses NPF-11 & NPF-18,changing Tech Specs Re Safety Relief Valve Setpoint & Setpoint Tolerances.Further Justification Provided

ML20135A534
Person / Time
Site:	LaSalle
Issue date:	09/05/1985
From:	Turbak M COMMONWEALTH EDISON CO.
To:	Harold Denton Office of Nuclear Reactor Regulation
References
0608W, 608W, NUDOCS 8509100186
Download: ML20135A534 (2)

Text

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. C N Commonwealth Edison -

) one First Nati nal Phza, Chicago. lifinois

[0 t 7 Address Reply to: Post Office Box 767 (j' Chicago, Illinois 60690 September 5, 1985 Mr. Harold R. Denton,. Director Office of Nuclear Reactor Regulation U. S. Nuclear Regulatory Commission Washington, DC 20555

SUBJECT:

LaSalle County Station Units 1 and 2 Proposed Amendments to Technical Specification for Facility Operating License NFP-ll and W F-18 Revision to SRV.Setpoint and Setpoint Tolerances - Supplemental Information NRC Docket Nos. 373 and 50-374 --

REFERENCE (a): August 19, 1985 letter from H. Massin to H. Denton transmitting Tech Spec change request

Dear Mr. Denton:

- This letter supplements our submittal of August 19, 1985 (Reference a) by providing further justification in support of our request for a Technical Specification change.

The implication of retaining a lower bound of -l% on the SRV setpoints is the_ possibility of unnecessary testing of valves. For example, when the SRV's are removed and sent to the test facility at the upcoming Unit 1 outage, if any of the valves fall to meet the +1% set pressure tolerance, an additional sample of valves must be removed and tested. If any of these valves fail, then the remainder of the valves must be removed and tested. This would unnecessarily increase the length of time the unit is shutdown and would also increase the man-rem exposure during the additional valve removals and installations.

Test data from Crosby indicates the valves are set to +0%, -2% from nameplate. Therefore, valvet might very well be found outside the current Tech Spec lower limit tolerance (-l%) resulting in unnecessary additional testing.

The ASME rating practice requires an approved, preheated test loop where the accuracies are demonstrated. An SRV is preheated in the loop, then tested four times in a row. These four readings must fall within a 4%

scatterband or'the valve is rejected. By definition, the +1% and -3%

apportionment of the scatter band defines the nameplate setting of the SRV.

This is conservative because it~is the upper limit that assures the protective opening action of the SRV occurs at or below that particular J ,

pressure.

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l H. R. Denton September 5 1985 The LaSalle SRV's were rated in Crosby's ASE qualified test loop.

Valves that didn't meet the 4% scatterband were rejected. The valve ratings were engraved on the nameplate according to this +1%, -3% ASME procedure.

This gives about 95% confidence that the valves operate at or below the nameplate setting.-

Amendment 64 to the FSAR revised the 1146 psi set point to 1150 psi. These valves are set to a nameplate setting of 1150 psi.

1150 psi is the analytical limit used by General Electric in the SRV overpressure protection transient. analysis.

Commonwealth Edison is notifying the State of Illinois of this supplement to our request by transmitting a copy of this letter to the designated State Official.

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

One (1) signed original and ten (10) copies of this transmittal is provided for your use.

Very truly yours, i

g .E. CA M. S. Turbak Operating Plant Licensing Director HLM/crh cc: Region III Inspector-LaSalle A. Bournia - mR M. Parker - State of Ill.

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