B10421, Third Interim Deficiency Rept Re Min Charging Pump Flow Design,Initially Reported on 800614.Util Is Evaluating Proposal by Westinghouse to Upgrade Automatic Actuation of Power Operated Relief Valve.Final Rept by 820618

Third Interim Deficiency Rept Re Min Charging Pump Flow Design,Initially Reported on 800614.Util Is Evaluating Proposal by Westinghouse to Upgrade Automatic Actuation of Power Operated Relief Valve.Final Rept by 820618

ML20054J404
Person / Time
Site:	Millstone
Issue date:	06/09/1982
From:	Counsil W NORTHEAST NUCLEAR ENERGY CO.
To:	Haynes R NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION I)
References
10CFR-050.55E, 10CFR-50.55E, AEC-MP3-274, B10421, NUDOCS 8206280584
Download: ML20054J404 (2)

Text

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l c. es General Offices e Selden Street, Be lin, Connecticut 1 CONNECTICUT 06101 l ,

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June 9, 1982 Docket No. 50-423 AEC-MP3-274 B10421 Mr. Ronald C. Haynes Region 1 Office of Inspection and Enforcement U. S. Nuclear Regulatory Commission 631 Park Avenue King of Prussia, PA 10406

References:

(1) W. G. Counsil letter to B. H. Grier, Reporting of Potential Significant Deficiencies in Design and Construction, dated June 14, 1980.

(2) W. G. Counsil letter to R. C. Haynes, Reporting of Potential Significant Deficiencies in Design and Cciatruction, Interim Report; Minimum Charging Pump Flow, dated February 18, 1982.

Centlemen:

Millstone Nuclear Power Station, Unit No. 3 Third Interim Report in the Reporting of a Potential Significant Deficiency in Design; Minimum Charging Pump Flow As required by Title 10, Code of Federal Regulations Part 50, Paragraph 55(e), Northeast Nuclear Energy Company (NNECO) reported a potential significant deficiency in the design of Millstone Unit No. 3 in Reference (1). Reference (2) stated that after detailed evaluations by both Northeast Utilities Service Company (NUSCO) and Westinghouse it was concluded that for the case of a steam line or feedwater line break, concurrcnt with a loss of offsite power, adequate charging pump flow would be provided by the safety grade PORV's used on Millstone Unit No. 3.

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<s - sa The above conclusion is correct, but it should be noted that the safety grade PORV's are safety grade for the manual mode only. Presently we are evaluating a proposal by Westinghouse to upgrade the automatic l actuation of the PORV's to safety grade. There is still the question l

that, given the environment caused by a high energy line break inside containment, what will be the effect on the accuracy of the pressure transmitters. This is not known yet since the environmental qualifica-tion of these transmitters is still in progress. Because of the above question and economic considerations, we are reevaluating the develop-ment of an alternate solution to ensure minimum flow of the charging pumps which involves a modified recirculation flow path.

One additional concern was raised in Reference (2). That was whether or not a pressure transient would occur if off-site power was available and the auxiliary feedwater system functioned as designed. The evaluation of this concludes that a pressure transient will not occur if off-site power is available.

Per a May 24, 1982 telephone conversation between your Mr. E. J. Brunner and our Mr. J. M. Powers we have provided this update to Reference (2) on or before June 18, 1982 because insufficient information was available to provide an update sooner. It was intended that a final report would be provided by June 18, 1982. However, this is not possible since a final decision on which available alternative to implement, has not been made. As such, we will continue to inform you of further developments.

Very truly yours, NORTHEAST NUCLEAR ENERGY COMPANY

/ (MLdt '

W. G. Counsil Senior Vice President 4

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