ML20137E848

Application for Amends to Licenses NPF-11 & NPF-18, Revising RCS Safety/Relief Valve Setpoint & Setpoint Tolerances.Fee Paid

ML20137E848
Person / Time
Site:	LaSalle
Issue date:	08/19/1985
From:	Massin H COMMONWEALTH EDISON CO.
To:	Harold Denton Office of Nuclear Reactor Regulation
Shared Package
ML20137E852	List: ML20137E848 ML20137E858
References
0527K, 527K, NUDOCS 8508260087
Download: ML20137E848 (4)

Text

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OO Commonwe:lth Edison

) One First National Plaza. Chicago. Ilknois O Address Reply to: Post Office Box 767 Chicago, Illinois 60690 August 19, 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 W F-ll and W F-18 Revision to SRV Setpoint and.Setpoint Tolerances NRC Docket Nos. 50-373 and 50-374 Reference (a): Technical Specification 3/4.4.2

Dear Mr. Denton:

Pursuant to 10 CFR 50.59, Commonwealth Edison proposes to amend Appendix A, Technical Specification, to Facility Operating Licenses W F-ll and NPF-18. These amendment 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.

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

Commonwealth Edison requests that you consider this to be a high priority item. Review and approval, if appropriate, is required by the end of October,1985.

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

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H. R. Denton August 19, 1985 Please direct any questions you may have concerning this matter to this office.

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

Very truly yours,

%i H.L).Massin Nuclear Licensing Administrator 1m Attachments (A): Background and Discussion (B): Technical Specification Change to tPF-11 and tFF-18 (C): Evaluation of-Significant' Hazards Consideration cc: Region III Inspector - LaSalle A. Bournia - NRR M. Parker - State of 111.

SUBSC BED and S N to befor me this. - dav of.;t avisf- , 1985' G . 01^4 Notary Public

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ATTACHMENT-A

SUBJECT:

Revision to SRV SEtpo' int and Setpoint Tolerance BACKGROUND: The LaSalle County Station Technical Specifications and the BWR/5 Standard Technical Specifications require the reactor

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coolant system safety / relief valve (SRV) tolerence be + 1% of I the setpoint. This tolerance is excessively restrictive and should be revised to +1%, -3%.

DISCUSSION: The General Electric Company (GE) has reviewed the tolerance provisions of the setpoint for the Crosby SRV's used at LaSalle to see if they were consistent with the GE equipment specification 22A 6441 paragraph 3.2.1. The conclusion is that.

Technical Specification 3.4.2 which specifies the opening talerance for the LaSalle SRV setpoint can be changed from +1%

to a revised value of +1%/-3% based upon the following reasons:

1. By inherent design, the Crosby SRV has'a setpoint opening scatter band range of 4%. This was measured during life cycle qualification tests. This small range indicates good repeatability over prior models.

2. GE design specification required an initial ~ service tolerance between plus one percent (with confidence of more than 0.95) of the nameplate ASIE value and a low limit of 1067 psig. The 6XRX10 valve met this specification.

3. GE design specification on blowdown (paragraph 3.2.4) required that the blowdown be within the range of 2 to 11 percent of the nameplate permitted set pressure popping range. Crosby determined that this requirement was met by a tolerance of +1%/-3% on the ASME nameplate pressure setting (VPF #6115-18-2,' paragraph 6.3.6.5 in Crosby Instruction Manual I-11069).

4. The A94E Code (1983 Edition) Subsection NB-7000 identifies that the opening pressure tolerance for safety valves shall not exceed plus or minus 1% of the nameplate value for pressure settings over 1000 psi, unless a greater tolerance is established in the overpressure protection report and in the safety valve design specification. The overpressure protection evaluation considers only the maximum or high (limit) value of the opening pressure because the lower opening pressure (limit) is not pertinent to overpressure protection. The 1% number represents this upper tolerance limit.

~The lower setpoint pressure limit is to assure that the blowdown requirements (amount of pressure cecrement) minimizes or precludes valve fatique, mechanical mismatching of attachments /pertinances due to thermal effects, and fatique introduction into piping via flow / thermal / pressure cycling. Fatique usage for LaSalle SRV's are conservatively very low as shown in UFSAR Table 3.9.8 where the code required number of thermal cycles is 2000 but the LaSalle design is good for over 106 cycles.

5. LSCS overpressure protection reports (22A4342 Rev. 3) referenced in UFSAR Chapter 5 were based upon the +1% high tolerance limit as required by ASME Code. Therefore, there is no need to change that report nor the FSAR overpressure write-up.

The above information provides adequate basis for revision to Technical Specification 3.4.2 to the +1%/-3% set pressure tolerance range for the LaSalle SRV's.

The revision of the lowest SRV setpoint pressure from 1146 to 1150 psig reflects the latest GE design documents. The UFSAR Table 5.2-9 and 15.0-1 specifies these values.

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