ML20154H017

Special Rept:On 880815,B Channel Reactor Vessel Level Instrumentation Inoperable Due to Junction Thermocouple Probe Failure.Replacement Sensors to Be Purchased

ML20154H017
Person / Time
Site:	Fort Calhoun
Issue date:	09/14/1988
From:	Morris K OMAHA PUBLIC POWER DISTRICT
To:	NRC OFFICE OF ADMINISTRATION & RESOURCES MANAGEMENT (ARM)
References
LIC-88-807, NUDOCS 8809210145
Download: ML20154H017 (2)

Text

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Omaha Public Power District 1623 Harney Omaha. Nebraska 68102 2247

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September 14, 1988 LIC-88-807 U. S. Nuclear Regulatory Conimission ATTN: Document Control Desk Mail Station PI-137 Washington, DC 20555

References:

1. Docket No. 50 285

2. Technical Specification 2.21 and Table 2-10 Gentlemen:

SUBJECT:

Special Report on Heated Junction Thermocouple Inoperability Fort Calhoun Station Technical Specification Table 2-10, footnote (k) states that:

"With the number of OPERABLE channels one less than the minimum channels operable requirement,

1. either restore the inoperable channel (s) to OPERABLE status within 7 days of discovery of loss of operability if repairs are feasible during power operation (MODE 1), or

2. prepare and submit a special report to the Commission pursuant to Spec-ification 5.9.3 within 30 days of discovery of loss of operability out-lining the action taken, the cause of the inoperability, and the plans for restoring the system to operable status."

This letter is to inform you of the inoperability of Channel "B" of the Reactor vessel Level Instrumentation, and the actions taken to return the cf.annel to an operable status.

On October 30, 1987, Amendment 110 to the Technical Specifications became effer-tive. This amendment requires that two channels of the Heated Junction Thermo couples (HJTC) be operable for the purpose of indicating reactor vessel level.

A channel consists of eight sensors in a probe; and each sensor has an associ-ated heater element. A channel is considered operable if four or more sensors, two or more in the upper four and two or more in the lower four, are operable.

The probe assemblies are supplied by Combustion Engineering.

On August 15,1988 the 88 sensor of the 'B' channel Heated Junction Thermo-c.ouple Probe failed resulting in the 'B' channel Reactor Vessel Level Instru-mentation to be inoperable. OPPD is currently purchasing replacement senenre from Combustion Engineering to replace the inoperable sensors in the 'B' chan-nel. The 'A' channel Reactor Vessel Level Instrumentation is operable.

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U. S. Nuclear Regulatory Commission ,

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This letter is submitted to meet the requirements of Technical Spacifications 2.21, Table 2-10 and 5.9.3. If you have any questions please contact us.

Sincerely, l~

K.ld ,

fjy .

orris Division Manager Nuclear Operations KJM/rh cc: LeBoeuf, Lamb, Leiby & MacRae 1333 New Hampshire Ave., N.W.

Washington, DC 20036 R. D. Martin, NRC Regional Administrator D. D. Milano, NRC Project Manager P. H. Harrell, NRC Senior Resident Inspector t

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