ML20105C860
| ML20105C860 | |
| Person / Time | |
|---|---|
| Site: | Catawba  |
| Issue date: | 09/15/1992 |
| From: | Tuckman M DUKE POWER CO. |
| To: | NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM) |
| References | |
| GL-88-14, NUDOCS 9209230015 | |
| Download: ML20105C860 (3) | |
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UUKE POWER September 15, 1992 U.S. Nuclear Regulatory Commission ATrN: Document Control Desk Washington, D.C. 20555
Subject:
Catawbr. Nucle. Station, Units 1 and 2 Docket Nos. 50-413 and 50-414 Generic Letter 88-14, Instrument Air Supply System Problems Affecting Safety-Related Equipment Response Correction / Clarification Gentlemen:
Duke Power Company's initial response to Generic Letter 88-14, " Instrument Air Supply System Problems Affecting Sat' ty Related Equipment", was submitted by letter on May 8,1989. As e
a result of an independent dewpoint testing analysis performed at Catawba by the instrument air system (VI) System Engineer and the McGuire VI System Engineer during March 1992, an error in dewpoint icadings was identified in the Catawba portion of the response.
Accordingly, this letter constitutes a correction to the May 8,1989 response. Regarding the subject submittal's Attachraent 1, data results and first paragraph, the revised material should read as follows (the information pertaining to particulates and oil content data has not been changed):
SilmPJLPSIll DEpflitlllD Dryer Outlet A 42.4 Dryer Outlet B 47.2 Dryer Outlet C 5?.8 Dryer Outlet D 47.9 Unit 1 Turbine Bldg 42.9 Unit 1 Cont Mech Equip Bldg 51.3 Unit 1 Oil Skid 67.5 Unit '2 Turbine Bldg 43.9 Unit 2 Cont Mech Equip Bldg 51.3 Unit 2 Oil Skid 46.4 Auxiliary Bldg Elev 522' 8).8 9209230015 920915 PDR ADOCK 05000413 P
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Jl Document Control Desk Page 2 September 15,19%:
" Air quality testing is performed per a performance test procedure.
Per this procedure, dewpoints in the instrument air system are determined every six months, while oil concentration and particulate contamination are determined once per year. Sample locations for dewpoint monitoring include the Turbme lluildings, Auxiliary Buildings, Containment Mechanical Equipment BuFdings, and the Oil Skids."
For clarification purposes, it should be noted that the discovery of the error in dewpoint readings was made when questions were posed as to how Catawba was obtaining VI system dewpoint readings of 28F to 32F when the refrigerated air dryers are designed to produce 35F to 39F dewpoint.
This data indicated that the old Catawba l100DP hygrometer was not indicating properly. The actual dewpoints were much higher and exceeded the maximum allowed by ISA-Si.3-1975, Generic Letter 88-14, and SOER 88-01.
After the above sample testing, General Eastern, the manufacturer of the dewpoint hygrometers, was contacted in an effort to determine why the readings of the 1100DP hygrometer were different from those obtained by the Hygro-Mi hyerometer. The manufacturer recommended several suggestions, but the hygrometers still read approximately 10F - 15F difference.
Catawba's method of testing and the equipment used has not changed much over the last five years and the equipment is routinely calibrated.
The instrument air system will be monitored on a frequent basis to check for moisture in the lines by Operations performing a periodic blowdown of the system until a station modification is implemented in 1994 to replace the present four 700 CFM refrigerated air dryers with two 2000 CFM air purge dessicant dryers. With dess c.nt dryers in the instrument air system, the nuclear industry is observing dewpoint readings as low as -110F, depending on their location.
Shou'd there be any further questions concerning this matter or if additional informatioa is desired regarding this submittal, please contact LJ. Rudy at (803) 831-3084.
Very truly yours, we%
M.S. Tuckman IJR/s
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Do;ument Control Desk Page 3 September 15, 1992 xc:
S.D Ebneter, Regional Administrator Region II i-f W.T. Orders, Senior Resident inspector R.II. Martin ONRR s
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