ML20107J451
| ML20107J451 | |
| Person / Time | |
|---|---|
| Site: | Hope Creek  |
| Issue date: | 10/15/1984 |
| From: | Martin T Public Service Enterprise Group |
| To: | Murley T NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION I) |
| References | |
| NUDOCS 8411120054 | |
| Download: ML20107J451 (3) | |
Text
.
O Public Service Electric and Gas Cornpany
- Thornes J. Martin 60 Park Plaza, Newark, NJ 07101 201-430-8316 Mailing Address: P.O. Box 570, Newark, NJ 07101 Vice President Engineering and Construction October 15, 1984 Dr. Thomas E.
Murley, Administrator U.
S.
Nuclear Regulatory Commission Office of Inspection and Enforcement Region I 631 Park Avenue
- King of Prussia, Pennsylvania 19406
Dear Dr. Murley:
SIGNIFICANT CONSTRUCTION DEFICIENCY INDUCED VOLTAGE ACTUATIONS IN LOGIC MODULES HOPE CREEK GENERATING STATION On September 14, 1984, a verbal report was made to Region I, Of fice of Inspection and Enforcement representative, Mr. J.
Strosnider, advising of a potentially significant construc-tion deficiency concerning induced voltage actuations of the logic system supplied by Bailey Controls Company.
The following-final report is provided in accordance with 10CFR50. 55 (e).
Description of the Deficiency During preoperational testing performed by Public Service Startup Group, incorrect actuations of Bailey Controls Company Model-862 digital logic modules were noted in lE and non-lE circuits.
Field test results indicate that voltages were induced in the non-energized conductors by energized conductors in the same or adjacent cables.
As presently designed, the logic module circuitry does not adequately suppress or filter the. induced voltages.
The voltage sources causing the misoperations are identified as steady state 120VAC power and voltage spikes from deener-gizing coils used in circuit breakers.
Induced AC voltages varied from 30 to 90 VAC RMS.
Investigations indicate that the induced voltage levels are -sensitive to the number of 8411120054 841015 PDR ADOCK 05000354
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Dr. T. E. Murley 2
10/15/84 conductors energized in a multiconductor cable and several times less sensitive to adjacent energized cables.
It was found that the voltage spike induced by deenergizing the DC coils had a maximum peak amplitude of 200-300 volts and.the dampened discharge waveform had a duration of not more than 30 milliseconds.
- A total of 2,248 Model 862 logic modules, each with a maximum capacity of 8 inputs, are potentially affected.
Public Service has issued Startup Deviation Reports to document and control this design deficiency.
. Safety Analysis At ' Hope Creek the Bailey Controls Company Model 862 digital logic modules are used for input signal isolation for various safety related systems to include the Residual Heat Removal and Core Spray systems.
Had the problem gone uncorrected, inappropriate system actuation could have adversely affected the safe shutdown capability of the plant.
We therefore consider this condition to be reportable in accordance with 10CFR50.55 (e).
Corrective Action Bailey Controls Company has developed a circuit modification to the input signal isolation on the Model 862 logic card to discriminate between valid signals and induced voltages.
The modification consists' of the addition of electronic components to the filtering network (e. g., resistors, diodes, capacitors).
All Model 862 logic modules will be modified.
Very truly yours,
/
C Office of Inspection and Enforcement Division of Reactor Construction Inspection Washington, D.
C. 20555 NRC Resident Inspector - Hope Creek P. O. Box 241 Hancocks Bridge, NJ 08038 l'
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. 10/15/84 Records. Center Institute of Nuclear Power Operations 2100-Circle 75 Parkway, Suite 1500-
-Atlanta,:GA 30339 1
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