ML19207A392

Responds to IE Bulletin 79-13,Item 5a Re Adequacy of Procedures to Respond to Feedwater Line Breaks.Review Indicates Procedures Adequate to Respond to Accidents.Insp Planned During Sept 1979 Shutdown

ML19207A392
Person / Time
Site:	Millstone
Issue date:	07/13/1979
From:	Counsil W NORTHEAST UTILITIES
To:	Grier B NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION I)
References
NUDOCS 7908170365
Download: ML19207A392 (2)

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July 13, 1979 Docket No. 50-336 Mr. Boyce H. Grier, Director Region I Office of Inspection and Enforcement U. S. Nuclear Regulatory Commission 631 Park Avenue King of Prussia, PA 19406

References:

(1) B. H. Grier letter to W. G. Counsil dated June 25, 1979, ,

I transmitting I&E Bulletin #79-13.

(2) W. G. Counsil letter to R. Reid dated June 18, 1979.

Gentlemen:

Millstone Nuclear Power Station, Unit No. 2 Feedwater System Piping In Reference (1), the NRC Staff summarized relevant industry experience regarding examination of feedwater piping welds, and requested action of Northeast Nuclear Energy Company (NNECO) to address the postulated incr2ased likelihood of a feedwater line break.

Specifically, Item 5.a of Reference (1) requested a response on three items within twenty (20) days. Accordingly, the following information is provided,

a. "Your schedule for inspection if required by Item 1."

In accordance with the Reference (1) request, NNECO is preparing to perform the examination within the 90-day period. Plant shutdown is tentatively scheduled for September 1, 1979, subject to change based upon such considera-tions as system-wide reserve generating capacity and plant status during the period between the date of this letter and the scheduled inspection,

b. "The adequacy of you_ operating and emergency procedures to recognize and respond to a feedwater line break accident."

Emergency procedur s 2509, Steam Line Rupture, discusses and provides procedure guidance for feedwrter line breaks, as well as steam line breaks, as to their location, either upstream or downstream of their respective isolation valves, and requires the same response for similarly located failures on either line.

815 358 Q)

The specific provisions of the procedure include:

(1) Isolation. of the break, if possible, (2) Termination of feedwater flow through the break to minimize the cooldown rate and associated recctivity increase, and (3) Retention of a sub-critical condition via emergency boration flowpaths.

NNECO's review has concluded that the existing procedures are adequate to recognize and respond to a feedwater line break. They remain, of course, available for NRC Staff review on-site.

c. "The methods and sensitivity of detection of feedwater leaks in containment."

Detection of small feedwater leaks would be accomplished ith equipment which is also utilized for reactor coolant system leakage determination. The in-strumentation available is containment sump level, containment low range _

pressure, temperature and dew point. All four of these indications are monitored in the control room. If these parameters indicate an in-crease in high temperature fluid leakage, a containment inspection would determine the source. The sensitivity of these devices was indicated recently when a 1.4 gallon per minute reactor coolant system leak was reflected in all of the above-mer.tioned parameters. Detection of large feedwater leaks is covered by the symptoms indicated in the above-referenced emergency procedure 2509.

A report of the results of the examinations is scheduled to be provided within 30 days of completion of the inspection. As documented in Reference (2),

NNECO's conclusion that Millstone Unit No. 2 can continue to operate safely in accordance with the provisions of DPR-65 remains unchanged.

Very truly yours, NORTHEAST NUCLEAR ENERGY COMPANY dhNA W. G. Counsil Vice President 815 359

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