ML20028G450

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Responds to 820727 Telcon Re Periodic Verification of Proper Instrument Air Quality.Design of Compressed Gas Sys Assures Proper Instrument Air Quality & High Degree of Reliability to All safety-related Pneumatic Components
ML20028G450
Person / Time
Site: Shoreham File:Long Island Lighting Company icon.png
Issue date: 02/03/1983
From: James Smith
LONG ISLAND LIGHTING CO.
To: Harold Denton
Office of Nuclear Reactor Regulation
References
SNRC-832, NUDOCS 8302090364
Download: ML20028G450 (3)


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SHOREHAM NUCLEAR POWER STATION g 4 E-wr m* w o . . P.O. BOX 618, NORTH COUNTRY ROAD + WADING RIVER, N.Y.11792 Direct Dial Number February 3, 1983 SNRC-832 Mr. Harold R. Denton, Director Office of Nuclear Reactor Regulation U.S. Nuclear Regulatory Commission Washington, D. C. 20555 Periodic Verification of Proper Instrument Air Quality Shoreham Nuclear Power Station - Unit 1 Docket No. 50-322

Dear Mr. Denton:

This letter is in response to the telephone conversation of July 27, 1982 among E. J. Weinkam, R. Lobell and J. Wermeil of the Nuclear Regulatory Commission, J. Riley and R. W. Grunseich of the Long Island Lighting Company. The discussion addressed the NRC concern that individual testing to verify the failure mode of pneumatically operated, safety-related components does not necessarily demonstrate that the particular component will fail in the same manner under postulated deteriorated air quality conditions. The NRC stated that the preoperational loss of air test need not be re-performed, however, they suggested that veri-fication of proper air quality at the dryer discharge outlet be done during refueling outages to preclude potential air quality problems.

The instrument air system supplies compressed air to all safety related air operated components outside primary containment.

The system is designed to minimize the possibility of system air contamination. Three multistage, centrifugal oil free compressors supply a common instrumentation service air header. Compressed air passes through one of two prefilters, a dual tower air dryer and one of two after filters before entering the instrument air header. The dryer operates automatically to shift and reactivate towers. The system is designed to produce air with an exit dew-point of -400F and provide filtering of 100% of all contaminants greater than 1 micron in size. Proper air quality is continuously assured by the control room annunciator which signals air dryer trouble, i.e., high instrument air relative humidity at the dryer outlet.

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  • February 3, 1983 SNRC-832 Page 3 P

Should you have any questions or require further information, please contact this office.

. Very truly yours, J. L. Smith

, Manager, Special Projects

!~ Shoreham Nuclear Power Station RJT:mp 4 cc: J. Higgins All parties i

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.e-February 3, 1983 SNRC-832 Page 3 Should you have any questions or require further information, please contact this office.

Very truly yours,

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J. L. Smith Manager, Special Projects Shoreham Nuclear Power Station ,

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February 3, 1983 SNRC-832 Page 2 The'Shoreham Nuclear Power Station also incorporates administrative provisions to assure proper air quality. Once per shift plant operators inspect the air dryer skid and assure all' local alarms are clear. Every 18 months the instrument air dewpoint is determined independently, using portable instrumentation.-

.The plant preventative maintenance program specifies the following:

The dryer dessicant is inspected once a year and ,

replaced if it is broken up or contaminated with -

oil.

The pre and after filters are inspected every 18 months and cleaned or replaced as necessary.

One dryer tower cycle is monitored every 18 months to assure proper control of the dryer / regeneration sequence.

Proper operation of the air dryer trouble annunciator and the associated. humidity' instrumentation at~the dryer discharger is verified every 18-months.

Nitrogen gas is supplied to pneumatically operated components inside

.pr imary conti a nment via the primary containment inerting system.

j Bulk liquid nitrogen, stored in an 11,000 gallon tank, is vaporized j and heated as necessary to satisfy system demand. Two banks of nitrogen bottles (Active / Reserve) function as redundant supplies in the event that the main tank is unavailable. There is a crosstie to the compressed air system, but locked closedi valves and adminis-trative controls prevent inadvertent usage.

i The nitrogen is supplied from offsite sources. LILCO purchase spe-

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l cifications will be drafted to assure high quality nitrogen-to preclude the possibility of system contamination.

LILCO believes that the design of the compressed' gas systems, in conjunction with preventative maintenance schedules and operator surveillance. requirements, assures proper instrument air quality and a high degree of reliability to all safety related pneumatic components.

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