ML20206G539

SER Supporting Employee Concern Element Rept OP 30204, Ground Detector Problem

ML20206G539
Person / Time
Site:	Sequoyah
Issue date:	11/04/1988
From:	NRC OFFICE OF SPECIAL PROJECTS
To:
Shared Package
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References
NUDOCS 8811220309
Download: ML20206G539 (2)

Text

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i SAFETY EVALUATION REPORT BY THE OFFICE OF SPECIAL PROJECTS EMPLOYEE CONCERN ELEMENT REPORT OP 30204, "GROUND DETECTOR P10BLEM" TENNESSEE VALLEY AUTHORITY l

SEQUOYAH NUCLEAR POWER PLANT UNITS 1 & 2 1

DOCKET NOS. 50-327 AND 50-328 4

1 1.

Ebfect Category:

Oner4tions (30000) i Subca tegory:

Cable and Contuit (30200)

Elerent:

GroundbetectorProblem(30204) i 1

The basis for Element Report 302.0? - SQN, Rev. I datec September 30,1986, is the following erployee concern SQN-86-013-001 which states.

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"Changing out the Sy!vania bulas in various group detector causes t.

resistance change which shows a ground between all three phases on the boarc when the test button is pushed. This false ground signal l

i otershadows an actual ground on the board, since the bulb lights up trighter than the other bulbs indicating a ground although an actal j

ground cay be on one of the other phases."

y II. Summary of Issue 1

i Ccncern 50M-60-013-001 references the potential of replacement bulbs in i

t various grcuna fault detectors giving false indications.

III. Eva'uation

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The evaluator conducted interviews with various singineering, raintenance, and cperations personnel and rev ewed schematic ciagrims of the grouno detection

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i circuits.

The concern was substantiated that both partial and full false i

grounc fault indicetions on the ground detectors have vccurred in the past.

l TVA has committee to have plastic tags placed near the ground detector bulbs en the unit anc shutdown beards stating "Replace Grcund lights as a set of tnree SYL 1%0V Bulbs Cnly" and "Verify all Greund Lights good prior to

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IV. Conclusion The fiRC staff believes that the TVA investigation of the concern was adequate, and their resolutien of the cor.cern as described in Element Report OP 30?O4 is acceptable for rcstart.