ML20052J076

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RO P-RO-82-7:on 820501,rod Control Sys Component Failed Causing Loss of Drive Motion for Some Rods.Caused by Failed Bridge Thyristor in Power Cabinet 1BD.Unit Brought to Hot Shutdown & Rod Control Sys Repaired on 820502
ML20052J076
Person / Time
Site: Prairie Island Xcel Energy icon.png
Issue date: 05/14/1982
From: Tierney F
NORTHERN STATES POWER CO.
To: James Keppler
NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION III)
References
RO-P-RO-82-07, RO-P-RO-82-7, NUDOCS 8205240403
Download: ML20052J076 (1)


Text

NSD NORTHERN STATES POWER COMPANY PilAllllE ISLAND NUCLEAll GENEllATING PLANT 1111 # 2

\Velch, 31N 55089 May 14, 1982 D-Mr. James G. Keppler, Director Region III Office of Inspection & Enforcement U.S. Nuclear Regulatory Commission 799 Roosevelt Road Glen Ellyn, IL 60137 Attention: J. F. Streeter Reportable Occurrence No. P-RO-82-7 On May 1, 1982, during conduct of the biweekly Control Rod Exercise Test, a component in the Unit 2 rod control system failed, resulting in loss of drive motion for some control rods. Analysis determined that the problem was in the control rod drive mechanism power supply system and that all control rods were capable of being tripped.

On bby 2nd the unit was brought to hot shutdown to repair the rod control system. A Notification of Unusual Event was declared at 1220 on bby 2nd; it was lif ted at 1451.

The problem was determined to be a failed bridge thyristor in power cabinet IBD. This resulted in insufficient power to actuate the movable grippers for control rods in Control Bank B, Control Bank D and Shutdown Bank B.

Since it was determined that no control rods were inoperable, it has been concluded that this event is not reportable.

Since ely p l

F. . 'icrn . .v' Plant Mana r ()

Prairie Island Nuclear Plant FPT/jm cc: L. O. Mayer Director, MIPC (2)

% Distribution Services Branch, DDC, ADM C. D. Feierabend 8205240400 820514 -

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