ML20198R775
| ML20198R775 | |
| Person / Time | |
|---|---|
| Site: | Vogtle  |
| Issue date: | 05/29/1986 |
| From: | Bailey J GEORGIA POWER CO., SOUTHERN COMPANY SERVICES, INC. |
| To: | Youngblood B Office of Nuclear Reactor Regulation |
| References | |
| 0513V, 513V, GN-934, NUDOCS 8606100208 | |
| Download: ML20198R775 (4) | |
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Georgia Powsr Company Routa 2. Box 299A Waynesboro, Georgia 30830 Telephone 404 554-9961 404 724-8114 Southern Company Services. Inc.
Post Office Box 2625 Birmingham, Alabama 35202 Telephone 205 870-6011 Vogtle Proj.ect May 29, 1986 Director of Nuclear Reactor Regulation File: X7BC35 Attention:
Mr. B. J. Youngblood Log:
uN-934 PWR Project Directorate #4 Division of PWR Licensing A U. S. Nuclear Regulatory Commission Washington, D.C.
20555 NRC DOCKET NUMBERS 50-424 AND 50-425 CONSTRUCTION PERMIT NUMBERS CPPR-108 AND CPPR-109 V0GTLE ELECTRIC GENERATING PIANT - UNITS 1 AND 2 SER OPEN ITEM 14: SAFETY PARAMETER DISPLAY SYSTEM (SPDS)
Dear Mr. Denton:
In a meeting with your staff on February 26, 1986, GPC stated that it would provide the SPDS validation algorithms. Attached please find the information requested.
If your staff requires any additional information, please do not hesitate to contact me.
Sincerely, J. A. Bailey Project Licensing Manager JAB /sm Attachment xc:
R. E. Conway G. Bockhold, Jr.
R. A. Thomas NRC Resident Inspector J. E. Joiner, Esquire D. C. Teper B. W. Churchill, Esquire W. C. Ramsey M. A. Miller L. T. Gucwa B. Jones, Esquire Vogtle Project File 0513V h
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4 ATTACIDIENT Vogtle Emergency Response Facility (ERF) Computer System
- Validation algorithm for redundant anelog sensors -
The ERF Computer System has provisions to validate from two (2) to six (6) redundant analog inputs. These inputs are averaged as detailed below to form calculated values, which are used if available to determine the status of the Vogtle Critical Safety Functions (CSFs).
If the validated parameter is bad or questionable (see below), the status of the CSF will be presented to the operator as questionable.
The matrix following shows decisions used for obtaining the validated average. The notes below pertain to comments referenced in the matrix:
NOTE 1:
For all cases below, an input is considered BAD if either:
- 1. The input value is outside the scale range.
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- 2. Hardware failure detection indicates problem, or i
- 3. The input has been manually removed from service.
- The input is considered good if not BAD.
NOTE 2:
For all cases below, delta is defined as a percentage of range. Each calculated value may be assigned a unique value of delta.
NOTE 3:
Calculated value is that of. good input, quality is questionable.
NOTE 4:
If the two inputs agree within delta of each other, calculated value is the average and quality is good. If the inputs are not within delta, calculated value is BAD, quality is BAD.
NOTE 5:
If the two inputs agree within delta of each other, calculated value is the average and quality is questionable.
NOTE 6:
All good inputs are averaged. If all inputs are within delta of the average, the calculated value is the average and quality is good. If all inputs are not within delta of the average, the input with the greatest deviation is discarded, and the remaining inputs averaged again. If all inputs are now within delta of the average, the calculated value is the new average and quality is questionable. If all inputs are still not within delta of the average, calculated value is BAD, quality is BAD.
i NOTE 7:
All good inputs are averaged. If all inputs are within delta of the average, the calculated value is the average and quality is questionable. If all inputs are not within delta of the average, the input with the Treatest deviation is discarded, and the remaining inputs averaged again. If all inputs are now within delta of the average, the calculated value is the new average and quality is questionable. If all inputs are still not within delta of the average, calculated value is BAD, quality d s BAD.
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6 8
e REDUNDANT INPUT MATRIX I
NUMBER OF NUMBER OF GOOD INPUTS INPUTS 0
1 2
3 4
5 6
2 BAD NOTE 3 NOTE 4 3
BAD NOTE 3 NOTE 5 NOTE 6 i
4 BAD NOTE 3 NOTE 5 NOTE 7 NOTE 6 E
1 5
BAD NOTE 3 NOTE 5 NOTE 7 NOTE 7 NOTE 6 6
BAD NOTE 3 NOTE 5 NOTE 7 NOTE 7 NOTE 7 NOTE 6 t
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r Vogtle Emergency Response Facility (ERF) Computer System
- Validation algorithm for dual contacts -
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Many of the ERF digital inputs originate from dual limit switches, i.e.,
two contacts monitccing the same valve, one indicating open/not open and one indicating closed /not closed. In order to provide the operator with the best information, the two inputs are combined to form one calculated digital input. The table below shows the validation logic used for calculated digital inputs:
Digital po.nt 1 Digital point 2 Calculated digital r
Valve open
- BAD -
Valve open, questionable Valve open Valve not closed Valve closed Valve open Valve closed
- BAD _
Valve not open, questionable Valve not open
- BAD -
Valve not open Valve not closed Valve intermediate Valve not open Valve closed Valve closed
- BAD -
- BAD _
- BAD -
- BAD -
Valve not closed Valve not closed, questionable
- BAD -
Valve closed Valve closed, questionable a
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