05000458/LER-1985-001, :on 850831,reactor Protection Sys Actuated on High Source Range Monitor Counts.Caused by Core Geometry Change When Fuel Initial Bundle Placed in Core.Four Fuel Loading Chambers Relocated to Eliminate High Count

:on 850831,reactor Protection Sys Actuated on High Source Range Monitor Counts.Caused by Core Geometry Change When Fuel Initial Bundle Placed in Core.Four Fuel Loading Chambers Relocated to Eliminate High Count

ML20138A506
Person / Time
Site:	River Bend
Issue date:	09/30/1985
From:	Williamson D GULF STATES UTILITIES CO.
To:
Shared Package
ML20138A454	List: 05000458/LER-1985-001, :on 850831,reactor Protection Sys Actuated on High Source Range Monitor Counts.Caused by Core Geometry Change When Fuel Initial Bundle Placed in Core.Four Fuel Loading Chambers Relocated to Eliminate High Count 05000458/LER-1985-002, :on 850904,reactor Protection Sys Actuated on High Main Steam Line Radiation & High Scram Discharge Vol Level.Caused by Reactor Protection Sys Channel a Manual Trip During Calibr Coupled W/Inadvertent Noise Spikes 05000458/LER-1985-003, :on 850904,full Reactor Protection Sys Actuation Occurred.Caused by Unintentional Shorting of Contact While Attempting to Install Jumper.Fuse C71-F7A Replaced & Jumpers Moved to Terminal Blocks 05000458/LER-1985-004, :on 850906,discovered That APRM Weekly Reactor Protection Sys Tests for Channels B,D,E,G & H Unsatisfactory Per Requirements for Setdown Neutron Trip.Caused by Exclusion of Steps to Verify Half Scram 05000458/LER-1985-005, :on 850913,reactor Protection Sys Actuation Occurred.Caused by Operator Error When Intermediate Range Monitor Channel E Mode Switch Inadvertently Moved from Operate to Standby.Switch Placed in Operate Position RBG-22182, Forwards LERs 85-001-00,85-002-00,85-003-00,85-004-00 & 85-005-00
References
LER-85-001, LER-85-1, NUDOCS 8510080578
Download: ML20138A506 (2)

LER-1985-001, on 850831,reactor Protection Sys Actuated on High Source Range Monitor Counts.Caused by Core Geometry Change When Fuel Initial Bundle Placed in Core.Four Fuel Loading Chambers Relocated to Eliminate High Count

Event date:
Report date:
4581985001R00 - NRC Website

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l At 0350 on 8-31-85, with the unit suberitical during t!.c performance of 1-ST-3 (Fuel Load), the Reactor Protection System actuated on liigh Source Range Monitor (SRM)

This was caused by the core geometry change when the initial fuel bundle was counts.

placed in the core.

The operator on the refueling platform relocated the four fuel loading chambers in the core to eliminate the liigh SRM counts. The health and safety of the public was not affected.

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sace mawnn On 8-31-85, with-the unit suberitical, Operations was performing 1-ST-3 (Fuel Load).

During the performance of this procedure, the Reactor Protection system (RPS) actuated on liigh Source Range Monitor (SRM) counts due to the high count rate on Fuel Load Chamber (FLC) "D".

This occurred when the initial fuel bundle was placed in the core.

The causes of this RPS actuation were the geometry of the fuel bundles, the sources and thg fuel loading chambers together with the lower SRM scram setpoint of 2 X 10 cps.

Because these conservative parameters were dictated by 1-ST-3, which is consistent with USNRC Regulatory Guide 1.68, Technical Specifications, and the River Bend FSAR, the RPS actuation was unavoidable.

The corrective action taken by Operations was to relocate the four FLCs to locations in the core at sufficient distances from the sources and the fuel cells being loaded.

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