ML18102A559

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Part 21 Rept Re Defect in NUS Model OCA801 Signal Isolator Modules.Replacement Modules Installed in Reactor Control & Protection Sys
ML18102A559
Person / Time
Site: Salem PSEG icon.png
Issue date: 08/08/1996
From: Eric Simpson
Public Service Enterprise Group
To:
NRC
References
REF-PT21-96741 NUDOCS 9611200167
Download: ML18102A559 (3)
v • d • e


Text

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Initial 10 CFR 21 Notification NUS Summator and Isolator Modules I. NAME AND ADDRESS OF THE INDIVIDUAL(S) INFORMING THE COMMISSION.

NAME: E. C. Simpson Senior Vice Presiqent - Nuclear Engineering ADDRESS: Public Service Electric and Gas Company P.O. Box 236 Hancock's Bridge, NJ 08038 H. IDENTIFICATION OF THE FACILl1Y, ACTIVITY OR COMPONENT WHICH FAILS TO COMPLY OR CONTAINS A DEFECT.

The facility is the Salem Generating Station, Unit 2. The basic components are Reactor Control and Protection System signal isolator and signal summator modules.

  • lit IDENTIACATION OF THE FIRM SUPPLYING THE BASIC COMPONENTW1*UCH FAILS TO COMPLY OR CONTAINS A DEFECT.

The modules were manufactured by:

NUS P.O. Box 50736 Idaho Falls, ID 83405 IV. NATURE OF THE DEFECT OR FAILURE TO COMPLY AND THE SAFETY_,

HAZARD WHICH IS CREATED OR COULD BE CREATED.

NUS Model OCA801 signal isolator modules and Model MTH 801 Signal Summator Modules are being installed as replacements for modules in the Reactor Control and Protection System to provide improved reliability. During bench testing, an electrical connection with no solder was observed on a replacement summator module. All replacement summator and isolator modules for Salem Unit 2 were then inspected. Ten (of 222) modules were found to have unsoldered electrical connections. Another seven modules were found to have insufficient solder on at least one connection. Some of the defective connections

  • were covered by heat shrink insulation.

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The isolator modules function to provide electrical separation b~tween the Reactor Protection System (Class 1E) and the Process Control System (non-Class 1E) portions of the Reactor Control and Protection (RCP) instrument loops. The summator modules are used to algebraically combine analog ~nals, either adding or subtracting inputs in combination with module gain and bias. The summators accept up to four inputs and provide one summed and isolated output.

The reactor protection system is designed to assure that the system can perform its required functions in the event of a design basis earthquake.

The defect could affect the modules' ability to function during a design basis earthquake. It could result in a loss of redundancy sufficient to constitute a major degradation of essential safety related equipment.

V. THE DATE ON WHICH THE INFORMATION OF SUCH DEFECT OR FAILURE TO COMPLY WAS OBTAINED.

The information was obtained on June 28, 1996.

VI. IN THE CASE OF A BASIC COMPONENT WHICH CONTAINS A DEFECT OR FAILS TO COMPLY, IDENTIFY THE NUMBER AND LOCATION OF ALL SUCH COMPONENTS IN USE AT OR SUPPLIED FOR PSE&G FACILITIES SUBJECT TO THE REGULATIONS OF 10 CFR21_

222 replacement modules are being installed in the Salem Unit 2 Reactor Control and Protection System. The replacement modules for Salem Unit 1 have been returned to the vendor.

VII. THE CORRECTIVE ACTION WHICH HAS BEEN, IS BEING, OR WILL BE TAKEN; THE NAME OF THE RESPONSIBLE INDIVIDUAL OR ORGANIZATION; AND THE LENGTH OF TIME THAT HAS BEEN OR WILL BE TAKEN TO COMPLETE THE ACTION.

All replacement modules for Salem Unit 2 have been inspected by the vendor and repaired. All replacement modules for Salem Unit 1 have been returned to the vendor for inspection and repair.

PSE&G is investigating the cause of the defect with the vendor. Results will be provided when the investigation is complete.

VIII. ANY ADVICE RELATED TO THE DEFECT OR FAILURE TO COMPLY THAT HAS BEEN, IS BEING. OR WILL BE GIVEN TO PURCHASERS OR LICENSEES.

None.

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fACIUTY OR ORGANIZATION UNIT (Pog* J cf 2)

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  • lnclud* In accordance with 10 CFR 21.2'1jd1(3)(i), the attached initial notification is provided on the or planned, etc. 1 NUS Summator and Isolator modules. NUS Model OCA801 signal isolator modules and Model MTH 801 Signal Summator Modules are being installed as replacements for modules in the Reactor Control and Protection System to provide improved reliability. During bench testing, an electrical connection with no solder was observed on a replacement summator module. All replacement summator and !solator modules for Salem Unit 2 were then inspected. Ten (of 222) modules were found to have unsoldered electrical connections.

Another seven modules were found to have insufficient solder on at least one connection.

Some of the defective connections were covered by heat shrink insulation.

The iscla!or rmdu:les function to provide electrical separation between the Reaaoc P1ofa::ii0n. Syset\ !C!ass 1 E) and the Process Control System (non-Class 1E) portions of the Rea:::tnr Como! and Protection (RCP) instrument loops. The summator modules are used to algebraicaRy combine analog signals, either adding or subtracting inputs in combination with module gain and bias. The summators accept up to four inputs and provide one summed and isolated outpul The reactor protection system is designed to assure that the system can perform its required functions in the event of a design basis earthquake. The defect could affect the modules' ability to function during a design basis earthquake. It could result in a loss of redundancy sufficient to constitute a major degradation of essential safety related equipment All replacement modules for Salem Unit 2 have been inspected by the vendor and repaired. All replacement modules for Salem Unit i have been returned to the vendor for inspection and repair. PSE&G is investigating the cause of the defect with the vendor.

Results will be provided when the investigation is completed.

YES NO Will. BE ANYTHING UNUSU.t.L OR NOT UMOERSTOOO? YES NO (Explain abo**)

NflC RESIDENT x

STATE(s) (NJ) (DE:L} DID A~ STSrrl.IS FlJNCTION AS REQUIRED?

YES N /yt NO (Explain elbows)

LOCAL (LA.CT}

OTHER GOV. AGENCIES MODE Of OPERATION ESTIMATE FOR ADDITIONAL INFO UMTIL COR.RECT!O: RESTART 04TE: ON PAC£ 27 N ()

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