ML20134J480

Suppl Response to NRC Request for Addl Info Re Proposed Amends to Units 1 & 2.Calculations Encl

ML20134J480
Person / Time
Site:	Zion  File:ZionSolutions icon.png
Issue date:	11/08/1996
From:	Mueller J COMMONWEALTH EDISON CO.
To:	NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
Shared Package
ML20134J483	List: ML20134J480 ML20134J501 ML20134J536
References
NUDOCS 9611150226
Download: ML20134J480 (4)

Text

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Co'nmonwealth lilison Comp.in)  ;

Zion Generating Station '

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' Zion, J1. (dK199 2 97 Trl H G742084 November 8,1996 U.S. Nuclear Regulatory Commission Attn: Document Control Desk Washington, D.C. 20555

Subject:

Zion Station Units 1 and 2 Supplement to Response to Request for Additional Information Operating Licenses DPR-39 and DPR-48 NRC Docket Nos. 50-295 and 50-304

Reference:

1) Letter from R. P. Tuetken, Commonwealth Edison, to U.S. Nuclear Regulatory Commission, dated July 26,1996, - Application for Amendment to Facility Operating Licenses DPR-39 and DPR-48.

2) Letter from C. Y. Shiraki, U. S. Nuclear Regulatory Commission, to I. Johnson, Commonwealth Edison, dated October 18,1996, Request for AdditionalInformation

3) Letter from J. H. Mueller, Commonwealth Edison, to U. S. Nuclear Regulatory Commission, dated October 22,1996, Response to Request i for AdditionalInformation I This letter supplements Commonwealth Edison's (Comed's) response to an NRC Request for .

Additional Information regarding a proposed amendment to the Zion Station Units 1 and 2 2 Facility Operating Licenses.

Comed previously submitted, in Reference (1), a request to amend the Zion Station Technical Specifications. The proposed amendment would reme . : the requirements governing reactor coolant system pressure and temperature limits for heatup, cooldown, low temperature operation, and hydrostatic testing from the Technical Specifications. These requirements would be governed by a Comed controlled Pressure Temperature Limits Report (PTLR). The NRC subsequently issued a request for additional information (Reference. 2) concerning the proposed amendment. Comed's response to the NRC request was provided via Reference (3).

Comed has revised two of the calculations submitted via Reference (3); Calculation No. 22S- I B-004E-189, " Low Temperature Overpressure Protection (LTOP) Setpoint Calculation." and  ;}

Calculation No. 22S-B-004E-166, Revision 0, "COMS/LTOP Pressure Instrument Loop Accuracy Calculation." Copies of these revised calculations are provided as Attachments A and B to this letter, respectively. Revision bars in the attached copies indicate the specific changes to the calculations. A general discussion of the more significant changes is provided

)] i in the following sections.

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Revision I to Calculation No. 22S-B-004E-189 The calculation has been revised to correct the sign of the pressure difference due to static head, AP,w, as used in Section 6.

l The minimum temperature upon which the calculation is based has been changed from 65 F

to 60 F to be consistent with the minimum steady state temperature data point indicated in j WCAP-14664, " Zion Units I and 2 Heatup and Cooldown Limit Curves for Normal 1

Operation." This change affected the density value, p, used in the determination of static head in Section 4.2.

4 The value for instrument uncertainty, P io.m.,, unwniy, identified in Section 4.5 and used in ,

! Section 6 was changed to reflect the new value determined by a revision to Zion Calculation J

. No. 22S-B-004E-166, "COMS/LTOP Pressure Instrument Loop Accuracy Calculation." The I

revision to this calculation is discussed below.

4 h m I to Calculation No. 22S-B-004E-166 Th .,umption stated in Section 3.1 was revised to reference the applicable Comed methodology document. A new item,5.1.6, was added, to reference ISA-S67.04-1982, which currently is the edition of the standard accepted by the NRC via a Regulatory Guide.

The module temperature effects were recalculated as random variables, as specified by the vendor. The transmitter drift was adjusted to reflect the potential for the surveillance period to be extended 25%. For clarity, statements were added that transmitter bistable drift are 2a random values.

The assumed rage of temperatures to which the pressure instrument will be subjected has been changed from 65'F - 105'F, to a range of 65'F - 90 F, to more realistically reflect the temperatures that will be encountered during COMS operation. This is noted in a new Section 3.6, and affects the M&TE temperature error determination in Section 6.3.1.2.1.2, the pressure instrument temperature error determination in Section 6.3.1.5.2, and ultimately, the summary and conclusions in Section 7.

Overall Effect of Changes The overall effect of these changes, as indicated in the Summary and Conclusions in Section 7 of calculation No. 22S-B-004E-189, is that the minimum acceptable Appendix G Cune Pressure, based upon the current LTOP setpoint is 469 psig at 60"F, rather than 472 psig at 65"F as previously indicated. These values are conservative relative to the values used in WCAP-14664, and therefore the pressure / temperature curves provided in the WCAP remain valid.

j

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

Respectfully, r

i . 'I t *f J. H. Mueller Site Vice President Zion Station Attachments cc: NRC Regional Administrator - RIII  ;

Zion Station Project Manager - NRR  !

Senior Resident Inspector - Zion Station .

Office of Nuclear Facility Safety - IDNS IDNS Resident Inspector Zion NLA Reg. Assurance File -)

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Attachment A Zion Calculation No. 22S-B-004E-189, Revision 1 l

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