ML20236W828

Special Rept:Channel B Heated Junction Thermocouple Inoperable in Violation of 871030 Amend 110 to Tech Spec 2.21.Caused by Defective Heater Elements in Probe.Heaters Jumpered.Inoperable Sensors Will Be Replaced

ML20236W828
Person / Time
Site:	Fort Calhoun
Issue date:	11/30/1987
From:	Andrews R OMAHA PUBLIC POWER DISTRICT
To:	NRC OFFICE OF ADMINISTRATION & RESOURCES MANAGEMENT (ARM)
References
LIC-87-802, NUDOCS 8712080252
Download: ML20236W828 (2)

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Omaha Public Power District 1623 Harney Omaha. Nebraska 68102 402iS36 4000 November 30, 1987 LIC-87-802 U. S. Nuclear Regulatory Commission I Attn: Document Control Desk Washir.gton, 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 Specification 5.9.3 within 30 days of discovery of loss of operability outlining 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 it to an operable status.

On October 30, 1987, Amendment 110 to the Technical Specifications became offective. This amendment requires that two channels of the Heated Junction Thermocouple (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 associated 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.

Channel "A" HJTC has been operable since Amendment 110 went into effect; however, Channel "B" has not been operable for this period due to three (3) 8712080252 871130 /

PDR ADOCN 05000285 ' " * """" " """Y"

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9 U. S. Nuclear Regulatory Commission LIC-87-802-Page'2 defective heater elements in the probe. The heaters for the probe are electrically wired in series and powered from the Qualified Safety Parameter Display System (QSPDS) cabinet. In order to supply power to the intact heater l- elements, the defective elements must be "jumpered" with an equivalent resistor. Heater No. 4 was jumpered on October 22, 1987 and Heaters No. 5 and 7 were jumpered on November 16, 1987; therefore, Channel "B" was restored to operability on November 16, 1987 with two of the lower four sensors, and three of the upper four sensors operable. OPPD is in the process of purchasing replacements for those that are inoperable.

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

Sincerely,

@d a f**

R. t. Andrews Division Manager Nuclear Produrtion RLA/me cc: LeBoeuf, Lamb, Leiby & MacRae 1333 New Hampshire Ave., N.W.

Washington, DC 20036 R. D. M!rtin, NRC Regional Administrator A. Bon.'nia, NRC Project Manager P. H. Harrell, NRC Senior Resident Inspector l

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