ML20084F287
| ML20084F287 | |
| Person / Time | |
|---|---|
| Site: | Dresden  |
| Issue date: | 01/29/1973 |
| From: | Worden W COMMONWEALTH EDISON CO. |
| To: | Anthony Giambusso US ATOMIC ENERGY COMMISSION (AEC) |
| References | |
| 904, NUDOCS 8304210078 | |
| Download: ML20084F287 (2) | |
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SUBJECT DPR-19 DRESDEN NUCLEAR 80iER sTAIIUh Ua1T %:
THIS WILL CONFIRM A CONVERSATION WITH MR MAUHA 0F YOUH OFFICE e
AT 1530 HOURS THIS DATE COhCERNING CONDENSun Luw VnCUUM l
SCRAM St.NSUR DrtlF r. ROUTINE SURVEILLANCE l-23-75 FOUND SETTING OF PSL-2-505D HAD DRIFTED BELOW TECH. SPEC. OF 24 INCHES 1
l HIGH TO A SETTlhG OF 22.45 INCHES IGH. SWIICH n' AS RESET TO 2 3.25 1
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72 WEST ADAMS STREET
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POST OPPICE 802 F47* CH IC AG O, ILLINOl$40490 Dresden Nuclear Power Station R. R. #1 Morris, Illinois 60450 January 29, 1973 a
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SUBJECT:
LICENSE DPR-19, DRESDEN NUCLEAR POWER STATION, UNIT 2, V S_ECTION 6.6.B.3 0F THE TECHNICAL SPECIFICATIONS. /!7 c 6R
Dear Mr. Giambusso:
This is to report a condition relating to the operation of this ~h unitwhich,onJanuary13,197J,thesetpointofoneofthefourreactor I low pressure permissive switches (core spray and low pressure coolant injection initiation) drif ted slightly below the value given in Table 3.2.2 c of the Technical Specifications. 1 RJc PROBLEM AND INVESTICATION gg On January 13, 1973, during a routine calibration of the subject VW switches, one of the four switches setpoint was found to have drifted slightly below the Tech. Spec. limit of 300 psig. 4 The subject switch, PS-2-263-52Al, drifted from the previous setting l of 321 psig to 298 psig decreasing pressure. This switch is a Meletron, model 372-6SS-49A-292 with a range of 28-1400 psig and a stated accuracy of + 1%. The switch being 2 psig below the specified limit has no effect on the safe operation of the system. This is the first setpoint drift exceeding the lower limit (as l specified in the Tech. Spec's.) since the stations target setpoint was lowered from 350 psig to 325 psig in September,1972. / G . [ )% COPY SENT REGIONf y., 8304210078 750129 PDR ADDCK 05000237 3 PDR l 904 L I
c m - =. za= = =. :.= z===-- =.- = .-. m o . o Mr. A. Giambucco January 29, 1973 _ CORRECTIVE ACTION The switch setpoint was immediately recalibrated to trip at 324 psig decreasing pressure, approximately the center of the 50 psig allowable i span. l The investigation defined below will be instituted. 1. Analyze the procedure used by the Dresden instrument i mechanics to assure that no errors are introduced as a result of surveillance technique. 2. Test a Neletron model 372-6SS-49A-292 pressure switch under controlled laboratory conditions to verify its performance characteristics. 3. Consult with a Meletron Technical representative for their assistance in analyzing the problem. 4. Perform monthly calibration checks of all switches of this type until sufficient data is obtained to curtail the investigation. Sincerely, k.>tc.k.. &Y W. P. Worden Superintendent WPW:do N - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - ' - - - - - - - - - - - - - - - - - - - - - - - ~ - - - - ' - ^ - - - ' - - - - - - - - - - - ' ' ' " - - - - ' - - - - - - -}}