ML20203B009

Ro:On 860708,no Rod Down Indication Received for Transient Rod Until Carriage Driven In,During Performance of Manual Scram for Reactor Shutdown.Caused by Malfunction of Reactor Safety Sys Component.Repairs Underway

ML20203B009
Person / Time
Site:	05000128
Issue date:	07/10/1986
From:	Krohn J TEXAS A&M UNIV., COLLEGE STATION, TX
To:	Johnson E NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION IV)
References
NUDOCS 8607170385
Download: ML20203B009 (1)

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f TEXAS ENGINEERING EXPERIM ENT STATION THE TEXAS A&M UNIVERSITY SYSTEM

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COLLEGE STATION, TEXAS 77843-3575

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k NUCLEAR SCIENCE CENT R 409/845-7551 Mr. Eric Johnson Office of Inspection and Enforcement U.S. Nuclear Regulatory Commission 611 Ryan Plaza Drive, Suite 1000 Arlington, Texas 76012

Reference:

Reportable Occurrence of 8 July 1986 Reactor Safety System Component Malfunction

Dear Mr. Johnson:

On Tuesday, 8 July 1986 at 2326, a manual scram was performed for the purpose of reactor shutdown. The Reactor Operator and Senior Reactor Operator noted that no rod down indication was received for the transient rod until the carriage was driven in. On Wednesday, 9 July, it was noted during the pre-startup checks that raising the transient rod carriage without applying air caused the rod to raise also. A scram time check was then performed on the transient rod which produced a time in excess of the allowable. The Manager of Operations was notified of these results and reactor operations for the day were cancelled and repairs to the transient rod drive were commenced.

The failure of the transient rod to scram was a malfunction of a reactor safety system component and as such is a reportable occurrence under Technical Specification 1.29(b). The reactor has not been operated since the malfunction was discovered. It should also be noted that all other safety rods did scram and the reactor did shut down on the 8 July manual scram and that a shutdown by manual scram was also performed on the previous night at which time the transient rod did successfully scram. Repairs to the system are still underway at this time.

Respectfully submitted, b 0 w John L. Krohn, Manager Reactor Operations JLK/ym 8607170385 DR 860710 I ADOCK 05000128 PDR RESEARCH AND DEVELOPMENT FOR MANKIND gO