ML19352A119
| ML19352A119 | |
| Person / Time | |
|---|---|
| Site: | Dresden  |
| Issue date: | 09/29/1972 |
| From: | Worden W COMMONWEALTH EDISON CO. |
| To: | Anthony Giambusso US ATOMIC ENERGY COMMISSION (AEC) |
| References | |
| NUDOCS 8103110036 | |
| Download: ML19352A119 (2) | |
Text
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Dresden Nuclear Power Station or s Illinois 60450 h
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September 29, 1972 r
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Mr. A. Giambusso
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Directorate of Licensing
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,s U. S. Atomic Energy Coc: mission 1,t ( 6 Washington, D. C.
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SUBJECT:
LICENSE DPR-19, DRESDEN NUCLEAR POWER STATION, UNIT #2, SECTION 6.6.B.3 0F THE TECHNICAL SPECIFICATIONS.
Dear Mr. Giambusso:
This is to report a condition relating to the operation of the unit in which, on September 19, 1972, the setpoints of two of the reactor low pressure permis::ive switches (for opening core spray and low pressure coolant injection admission valves) drif ted beyond the values established in Table 3.2.2 of the Technical Specifications.
PROBLEM AND INVESTIGATQ,
l On September 19, 1972, during routine calibration of the reactor low pressure permissive switches (required every three months by Technical l
Specifications), two of the switches setpoints were found to have drif ted l
above the Technical Specifications value of 350 psig.
l l
The subject switches, PS-2-263-52A1 and FIS-2-263-52B2, were found set at 357 psig and 352 psig respectively. PS-2-263-51A1 is a Heletron switch, model number 372-6SS-49A-292 with a range of 28-1400 psig and an accuracy of + 17..
PIS-2-263-52B2 is an ITT Barton Switch, serial number 288-5560, with a range of 0-500 psig and an accuracy of + 0.2%.
l CORRECTIVE ACTION At the time of calibration, PS-2-263-52A1, and PIS-2-263-52B2 were l
reset to 345 psig and 346 psig reactor pressure respectively.
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Mr. A. Giambusos Srptember 29, 1972 J
These switches do not have a history of drifting. They have pre-viously been set as close to 350 psig as practical. Since these switches have a 50 psig permissive trip setting span (Table 3.2.2 of the Technical Specifications) they will be set to the center of this span to prevent future recurrences.
Sincerely, bb b Nsb W. P. Worden Superintendent Dresden Nuclear Power Ststion WFW:do f
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