ML17037B640

Letter Regarding a Determination That the Technical Specifications Should Be Revised to Incorporate Instrumentation System Requirements Which Meet the Enclosed NRC Staff Technical Position

ML17037B640
Person / Time
Site:	Nine Mile Point
Issue date:	02/04/1977
From:	Goller K Office of Nuclear Reactor Regulation
To:	Rhode G Niagara Mohawk Power Corp
References
Download: ML17037B640 (6)

Text

Docket Ho.60-220 Niagara Hoha~ik Power Corporation

'TTN: Hr. Gerald K. Rhode Vice President - Engineering 300 Erie Boulevard West Syracuse, Nev~ York 13202 Gentlemen:

RE: MINE ttILE POINT NUCLEAR STATION UHIT NO. 1

'Je have completed our preliminary review oi'he information you submitted on November 0, 1976, regarding the instrumentation systems available at your facility to monitor drywell to torus differential pressure (AP) and torus water level. This information was provided in response to our letter dated September 30, 1976, regarding Technical Specification requirements associated with the Hark I Containr>ent Short Tem Program Plant Unique Analyses.

Based on our revie~i of the information provided in your response and your existing Technical Specification requirements for instrumIentation systems I;hich could be used to monitor drywell to torus AP and torus water level, we have determined that. your Technical Specifications should be revised to incorporate instrumentation system requirements which meet the HRC staff technical position detailed in the enclosure. Consequently, you are requested to provide the following information and commitments within 20 days of receipt of this letter:

a. Your commitment to instal't instrumentation systems to monitor drywell to torus hP and torus siater level which meet the minimum requirements of the enclosed NRC staff technical position;

b. Your schedule for completion of the installation of such systems; and

c. Your commitment to request appropriate Technical Specification changes relating to this instrumentation follow)ng installation.

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Niagara Mohawk Po>ver Corporation - 2-Installation of the above-mentioned instrumentation systems and your request for appropriate Technical Specification changes should be accomplished in an expeditious manner but no later than April 15, 1977.

Karl R. Goller, Assi'stant Director for Operating Reactors Division of Operating Reactors

Enclosure:

NRC Staff Technical Position cc: Arvin E. Upton, Esquire LeBoeuf, Lamb, Leiby 8 ttacRae 1757 N Street, N. W.

t/ashington, D.,C. 20036 Anthony Z. Roisman, Esquire Roisman, Kessler and Cashdan 1025 15th Street,'. I$ .

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Mashington, D. C. 20005 ftr. Eugene G. Saloga, Applicant Coordinator Nine Nile Point Energy Information Center P. 0. Box 81 Lycoming, New York 13093 DISTRIBUTION:

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ENCLOSURE 1 NRC Staff Technical Position On Instrumentation S stems to Honitor Torus to Drywell Differential Pressure and Torus Water Level I

l In consideration of the significance of drywell to torus differentia'1 pressure (LP) control and torus water level control to the results of the Hark I Contaiment Short Term Program Plant Unique Analyses, we have concluded that a minimum of two narrow range instrument channels should be provided to monitor each of these plant parameters.

Operational experience indicates that pressure transducers tend to drift and water level indicators tend to stick; these observations, together with standard instrument calibration frequency requirements, form the basis for our requirements for a minimum of two instrument channels per parameter.

The significance of variations in drywell to torus zP and torus water level an/

the magnitude of the LOCA-related hydrodynamic loads on torus support systems forms the basis for our requi rement for narrow range instrumentation to accurately measure these parameters. The error-band of the instrumentation used to moni tor the drywell-wetwel differential pressure and the torus 1

water level should be small in comparison to the absolute value of the parameter being measured. Based on the load sensi tivity curves presented in Addendum 2 to the tlark I Containment Short Term Program Final Report and typical instrument accuracies, we conclude that the error in the hP measurement should be no greater than +0.1 psid and that the error in the torus water level measurement should be no greater than 10" of the difference between the maximum and minimum torus water level (i.e., if the difference between maximum level and minimum level = 4", then the instrument error should be <.4").

The Technical Specifications for each Hark I BWR facility (except Brunswick Units Nos. 1 and 2) should include requirements consistent with this position. Action to be taken in the event that one or both of the instrument channels is out of service should be consistent with other requirements for surveillance instrumentation.

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