ML20064D949
| ML20064D949 | |
| Person / Time | |
|---|---|
| Site: | North Anna  |
| Issue date: | 10/06/1978 |
| From: | VIRGINIA POWER (VIRGINIA ELECTRIC & POWER CO.) |
| To: | NRC COMMISSION (OCM) |
| References | |
| NUDOCS 7811130149 | |
| Download: ML20064D949 (1) | |
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A similar facility utilf zfeg a Westingttcuse APOMS Monitoring System for calculating LCCA peaking factor shape has discovered a non-conservative error in '.he etcroprecessor progract which determines the alarm setpoint envelope. The error is caused by a calculational round off which may increase in setsoint above the desired value by as muen as 1/2%. This equipment is presently being used at North Anna to nonttor the asial peaking factor. The innedtate action taken upon notification of this situation was to sutetit a devf ation report and to adjust tt'e present setpoint values down at least 1%
i to cort,ensate for this condition. The system has never alarmed to indicate that the setpoint =as exceeded since placed into service and an investigation is presently being conducted to determine if tite ceaking factor was ever within It of the setpoint.
Since the unit is normally at a stable pcwr level with acele margin with respect to the peaking factor lisit it is unlikely that this 11aitt has ever been enceeded considerir.g this error. In the future, this error will be taken into consideration when calculations to determine tne proper setpoints are performed.
j VEPCO North Anna Unit 1 NPF-4 Written Follow p to Event (LER/R0 78-98)
Westinghouse APDtS Deviation Telacopied by Date CCI
'O Time F
1 7811130/4/7 5
.