B10638, Advises That Extra Time Needed to Respond to Question 4 of NRC Re Measurement Uncertainties Used in Safety Analyses,Since Final Designs for Several Measurement Channels Not Yet Finalized

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Advises That Extra Time Needed to Respond to Question 4 of NRC Re Measurement Uncertainties Used in Safety Analyses,Since Final Designs for Several Measurement Channels Not Yet Finalized
ML20064G083
Person / Time
Site: Millstone Dominion icon.png
Issue date: 01/04/1983
From: Counsil W
NORTHEAST NUCLEAR ENERGY CO., NORTHEAST UTILITIES
To: Clark R
Office of Nuclear Reactor Regulation
References
B10638, TAC-48063, NUDOCS 8301110296
Download: ML20064G083 (2)


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(203) 666-6911 k ' J Y,E eNw$ cw 3anuary 4,1983 Docket No. 50-336 B10638 Director of Nuclear Reactor Regulation Attn: Mr. Robert A. Clark, Chief Operating Reactors Branch #3 U.S. Nuclear Regulatory Commission Washington, D. C. 20555

References:

(1) W. G. Counsil letter to R. A. Clark, dated November 4,1982.

(2) R. A. Clark letter to W. G. Counsil, dated August 19,1982.

(3) W. G. Counsil letter to R. A. Clark, dated March 4,1982.

Gentlemen:

Millstone Nuclear Power Station, Unit No. 2 Revised Schedule, Measurement Uncertainties Responses Reference (1) provided Northeast Nuclear Energy Company's (NNECO) partial response to questions concerning the measurement uncertainties utilized in the Millstone Unit No. 2 safety analyses. Additional time was necessary to complete our response to Questions 4 and 6 of Reference (2) and a schedule for providing this information was agreed to as documented in Reference (1).

It has become apparent since the docketing of Reference (1) that additional time will be necessary to complete our response to Question 4 of Reference (2) beyond the scheduled date of January 1,1983. This is due to the fact that final designs for several of the measurement channels scheduled for modification during the 1983 refueling outage have not been finalized. In addition, the calibration procedure requirements for the modified channels are still being developed. This information is necessary in order to accurately define the channel error allowances to be j utilized in the analysis of the measurement uncertainties for the new equipment.

It is NNECO's intention to provide the information responding to Question 4 of l Reference (2) by February 15, 1983. This information will incluae drif t allowances for the new measurement channels as well as actual drift data for the [ f measurement channels which were modified during the 1981-1982 refueling outage. D1 The channels addressed in the analysis of Reference (3) which were modified during /

'C the 1981-1982 outage include safety pressurizer pressure and steam generator pressure. The operating characteristics of the modified channels have been sxcellent with minimal drif t experienced since startup in March,1982. As such, NNECO does not expect the conclusions of the uncertainty analysis provided in Reference (3) to be affected by the modifications to the channel hardware.

l 8301110296 030104 PDR ADOCK 05000336 P PDR

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We trust you find this revised schedule satisfactory.

Very truly yours,  ;

NORTHEAST NUCLEAR ENERGY COMPANY

/. 44/yt W. G. Counsil '

Senior Vice President l e i

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