05000285/LER-1950-285, Documents Deletion of Licensing Basis Commitment in LER 50-285/77-5 Re Failure of Reactor Protective Sys Trip Unit to Trip Prescribed Setpoint,Due to Improper Pretrip & Trip Indication Bulbs in Trip Unit Circuitry

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Documents Deletion of Licensing Basis Commitment in LER 50-285/77-5 Re Failure of Reactor Protective Sys Trip Unit to Trip Prescribed Setpoint,Due to Improper Pretrip & Trip Indication Bulbs in Trip Unit Circuitry
ML20065P697
Person / Time
Site: Fort Calhoun Omaha Public Power District icon.png
Issue date: 04/21/1994
From: Gates W
OMAHA PUBLIC POWER DISTRICT
To:
NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
References
LIC-94-0086, LIC-94-86, NUDOCS 9404290242
Download: ML20065P697 (2)


LER-2050-285, Documents Deletion of Licensing Basis Commitment in LER 50-285/77-5 Re Failure of Reactor Protective Sys Trip Unit to Trip Prescribed Setpoint,Due to Improper Pretrip & Trip Indication Bulbs in Trip Unit Circuitry
Event date:
Report date:
2852050285R00 - NRC Website

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Omaha Pubilc Power District 444 South 16th Street Mall Ornaha, Nebraska 68102-2247 402/636-2000 April 21, 1994 LIC-94-0086 U. S. Nuclear Regulatory Commission AT'IN : Document Control Desk Mail Station Pl-137 Washington, DC 20555

References:

1. Docket No. 50-285
2. Letter from OPPD (W. C. Jones) to NRC (E. M. Howard) dated February 24, 1977 (LIC-77-0024)

Centlemen:

SUBJECT:

Deletion of Ongoing Commitment The purpose of this letter is to document deletion of a licensing basis commitment. Omaha Public Power District (OPPD) submitted Licensee Event Report (LER) 50-285/77-5 for Fort Calhoun Station (FCS) via Reference 2. This report concerned failure of a Reactor Protective System Trip Unit to trip at its prescribed setpoint, due to improper pretrip and trip indication bulbs in the trip unit circuitry. As a corrective action in the LER, OPPD wrote "...where two similar appearing bulbs are able to be installed in the RPS, the RPS trip unit's pretrip and trip lights will be checked and relamped as necessary on a weekly basis."

OPPD has reviewed the action quoted above as part of the FCS Ongoing Commitment verification program, in retrospect, the action is inappropriate and should be deletud as a licensing basis commitment. The resistance of the indication bulb contributes to the channel setpoint, such that installation of an incorrect bulb can result in an out-of-specification setpoint; however, a burned-out bulb will not change the setpoint significantly. Therefore, thc assurance that proper bulbs are used is more important than replacement of burned-out bulbs. A weekly illumination check and relamping does not in itself assure that proper bulbs are installed and setpoints are maintained within specifications.

The current procedures used at FCS provide configuration control by requiring that any proposed change to system or component design or characteristics, including bulb voltage or wattage, be evaluated and documented. In addition, the periodic functional tests of the trip units confirm proper setpoints and systera operability.

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U. S. Nuclear Regulatory Commission LIC-94 0086

~Pagd 2 To summarize, OPPD is deleting the ongoing commitment described above in LER 50--

285/77-5, since other administrative controls better address the cause of the event. Please contact me if you have.any questions.

Sincerely, lh&'-bh?yhhol2G1 W. G. Gates Vice President WCG/tcm c: LeBoeuf, tamb, Greene & MacRae L. J. Callan, NRC Regional Administrator, Region IV R. P. Mullikin. NRC Senior Resident Inspector S. D. Bloom, NRC Project Manager 1

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