ML20236R610

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Clarifies Util Summarizing 10CFR50.59 Changes to Facility in 1986.Containment Hydrogen Monitor Will Continue to Be Operated,Per Tech Specs.Commitment Made in Will Be Revised Re Operation of Instrument
ML20236R610
Person / Time
Site: McGuire, Mcguire  Duke Energy icon.png
Issue date: 11/19/1987
From: Tucker H
DUKE POWER CO.
To:
NRC OFFICE OF ADMINISTRATION & RESOURCES MANAGEMENT (ARM)
References
RTR-REGGD-01.097, RTR-REGGD-1.097 TAC-51104, TAC-51105, NUDOCS 8711230383
Download: ML20236R610 (2)


Text

- . .

DUKE POWER GOMPANY P.O. Box 33180 CHARLOTTE, N.C. 28242

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November 19, 1987 U.S. Nuclear Regulatory Commission Document Control Desk Washington, D.C. 20555

Subject:

McGuire Nuclear Station 1 Docket Nos. 50-369, -370 (TACS 51104 and 51105)

Gentlemen:

My letter dated October 28, 1987, which summarized the 10CFR 50.59 changes r.ade to McGuire in 1986, incorrectly stated the nature of the change made to Procedure IP/0/A/3250/39. The following discussions are provided to clarify the present design and operational capabilities of the containment hydrogen monitors of McGuire.

By letter dated March 29, 1984, Duke filed a report with the NRC describing how

, the requirements of RG 1.97 either had been or would be. met. In this report, the i containment hydrogen monitors were reported to have an indicated range of from 0-30%, and thus the McGuire Jesign was consistent with RG 1.97. l The monitor is designed to indicate up to 30% hydrogen concentration, if it is calibrated at 30%. However, McGuire technical specifications have always required l that such calibrations be made at 0% and 9% hydrogen concentration. This fact was omitted from the initial Duke RG 1.97 submittal. This requirement limits the i effective range of the monitor to between 0% and 9%.

l The procedure change described in my October 28, 1987 letter should have referred to the total rewrite of the procedure and revision .of the FSAR including the performance of calibrations at zero percent and nine percent as required by technical specifications (3/4.6.4.1) rather than revising the scales of the instrument. While there is no Bases provided in technical specifications for these calibration values, it is known that they are close to the hydrogen con-centrations of interest for explosive gas mixtures. Also, this range envelopes all emergency procedure requirements for the monitoring of hydrogen concentration and subsequent operator action. Calibration at 30% hydrogen concentration (the upper limit of RG 1.97) would reduce the accuracy of readings and the effective-ness of the monitor at lower concentrations of interest.

B711230383 871119 PDR ADOCK 05000369 P PDR u q<7 d6

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  • Document Control Desk -

November 19, 1987 Page 2 )

f Duke believes that the most appropriate course of action at this point is to i continue operation of the containment hydrogen monitor pursuant to the technical specifications and to revise the commitment made in the letter of March 29, 1984 1

regarding the operation of this instrument.

Should the Staff desire any further discussion on this issue, please contact us.

through the normal licensing channels.

Very truly yours,

& 7 J Hal B. Tucker RLG/320/jgc xc: Dr. J. Nelson Grace Regional Administrator U.S. Nuclear Regulatory Commission  !

Region II 101 Marietta Street, NW, Suite 2900 Atlanta, Georgia 30323 l

l Mr. Darl Hood, Project Manager Office of Nuclear Reactor Regulation q i

U.S. Nuclear Regulatory Commission  !

l Washington, D.C. 20555 i

3 Mr. W.T. Orders NRC Resident Inspector McGuire Nuclear Station l

1 l