ML20234D384

Special Rept:On 871229,Channel a of Reactor Vessel Level Instrumentation Sys (RVLIS) Declared Inoperable.Caused by Hydraulic Isolator Failure.Adjustment Made.Failed Power Supply in RVLIS Channel B Replaced & Channel Made Operable

ML20234D384
Person / Time
Site:	Trojan File:Portland General Electric icon.png
Issue date:	12/30/1987
From:	Olmstead C PORTLAND GENERAL ELECTRIC CO.
To:	NRC OFFICE OF ADMINISTRATION & RESOURCES MANAGEMENT (ARM)
References
CAO-479-87, NUDOCS 8801070002
Download: ML20234D384 (1)

Text

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December 30, 1987 {-

Portland General lilectric Company .

CAO-479-87 Trojan Nuclear Plant 71760 Columbia River liwy Rainier, Oregon 97048 I (503) 556-37I3 U.S. Nuclear Regulatory Commission Document Control Desk Washington, D. C. 20555 Gentlemen:

1 Special Report Limiting Condition for Operation (LCO) 3.3.3.9 of the Trojan j Technical Specifications requires the submittal of a Special '

Report if less than the minimum number of accident monitoring instrumentation channels shown in Technical Specification Table 3.3-11 are operable. On December 29, 1987, the "A" channel of the reactor vessel level instrumentation system (RVLIS) was declared inoperable due to an apparent hydraulic isolator failure.

Engineering was contacted to review this apparent failure, however, system experts were not available at the time of failure to conclusively determine the effect of the apparent hydraulic '

isolator failure on system operability. Therefore, the conservative decision was made to make an immediate telephone notification of I this condition per LCO 3.3.3.9 at 2145 hours0.0248 days <br />0.596 hours <br />0.00355 weeks <br />8.161725e-4 months <br /> on December 29, 1987.

The "B" channel had previously been considered inoperable due to a failure of the remote indication for that channel.

Subsequent investigation on December 30, 1987 revealed that whi's the "A" channel was in an alarm condition based on hydraulic isolator displacement, the "A" channel was still operable and providing valid indication of reactor vessel water level.

Therefore, since the Technical Specification required minimum l number of channels was met, no entry into the action statement for LCO 3.3.3.9 was required.

A failed power supply in the "B" RVLIS channel was replaced and this channel was declared operable on December 30, 1987.

Sincerely,

, 'A l eg C. A. Olmstead l

mo General Manager '

no

-o l NW CAO/RPS/DW / :fv c: Mr. Dave Yaden, Direc to:: Mr. R. C. Barr

$$ State of Oregon USNRC Resident Inspector go Department of Energy Trojan Nuclear Plant 7, Ne ,6 l y Mr. John B. Martin Distribution gg Regional Administrator k b J

mam US Nuclear Regulatory Commission I l