ML17037C530

Confirms 09/18/1973 Telephone Conversation with P.A Burt Regarding Possibility of Inverted Poison Tubes in the Control Rods at the NMP Unit 1

ML17037C530
Person / Time
Site:	Nine Mile Point
Issue date:	09/25/1973
From:	Skovholt D US Atomic Energy Commission (AEC)
To:	Raymond P Niagara Mohawk Power Corp
References
Download: ML17037C530 (4)

Text

Docket No. 50-220 Niagara kfohawk Power Corporation ATTN: Hr. Philip D. Raymond Vice President Engineering 300 Erie Boulevard Hest

Syracuse, New York 13202' Gentlemen:

This is to confirm our telephone conversation with Hr. P. A. Burt, General Superintendent, Nuclear Generation, on September 18, 1973, regarding the possibility of inverted poison tubes in the control rods at the Nine Nile Point Nucleax Station Unit 1 (NHP-1). It was agreed that in the event of an unscheduled shutdown of NHP-1 within the next 90 days, you would conduct shutdotm margin tests on all control rods to verify f:hat the minimum shutdown margin is at least 0.0075 delta k/k at cold, xenon-"free, operating samarium conditions.

It is expected that, these tests willbe performed making adequate allowance for the shutdown worths of xenon and samarium.

In the absence of an unscheduled shutdown, you are requested to schedule a shutdown to perform-these shutdown margin tests within 90 days from the date of this letter.

You are requested also to provide this office with a written.report.of the results of these tests within, 10 days of their completion. If any anomaly is found, report in accordance with the requirements of the Technical Specifications of Incense No. DPR-17 for NHP-1.

Successful completion of these shutdown reactivity margin measurements assures. that an adequate shutdown margin exists at the time of the measurement.

Our review of the inverted poison rod occurrence indicates that insufficient data exists to conclude. that further poison redis-tribution cannot occur.

Therefore, you are requested to submit, the following information for our review:

(1) analyses of possible length and location of poison voids which could be caused by boron carbide redistribution, (2) the effect of such redistribution on normal operation',.

transients, and accidents, (3) proposed changes to technic'al specifi-cations which.will assure that all safety margins stated or implied in your PSAR are maintained, (4) surveillance requirements to maintain adequate shutdown reactivity margins and monitor changes in poison distribution, (5) your plans and schedules for changeout of contxol

rods, and (6) expected curve of reactivity vs burnup for remainder of current operating cycle.

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Magara Hohawk Power Corporation SEP 2 5 1973 Copies of the "Reactor'ontxol Blade Evaluation" special report and supplement submi'tted by The Hillstone Point Company along with our reply and safety evaluation axe enclosed to serve as guidance in the preparation of your submittal.

Xt is requested that any proposed changes within your Technical Specifications to account far poison redistribution in inverted poison tubes be implemented upon submittal pending completion of our review of your proposed changes.

- Your response in this axea is requested within 45 days from the date of completion of the initial shutdown margin testing and,should be sub-mitted as thr'ee signed and thirty-seven additional copies.

Sincerely, Ortginal,"Signorl by D. 7. Shnrholt Donald J. Skovholt Assistant Director for Operating Reactors Directorate of Licensing J

Eaclos urea:

l, Hillotone ltrs dtd 7/23 & 7/26/73 transmitting Reactor Contxol Blade Evaluation and Supplement 2.

AEC ltr to Hiklstone dtd -7/27/73 and Safety Evkluation cc w/enclosures s

J. Bruce HacDonald, Esquixe Deputy Commissiancr and Counsel Hew York State Department of Commerce and Counsel to the Atamic Energy Council Axvin E. Upton', Esquire LeBoeuf, Lamb, Leiby & HacRae Dr. William Seymour Staff Coordinator Hew York State Atomic Energy Council Hcv York State Department of Commerce Oswego City Library Distribution ocket F

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