ML20086E185

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AO 50-267/74/4A:on 740419,during Replacement of Control Rod Drive 6,manual Retract Tool Jammed W/Manual Retract Gear. Cause Unknown.Tool Redesign May Be Required
ML20086E185
Person / Time
Site: Fort Saint Vrain Xcel Energy icon.png
Issue date: 04/19/1974
From: Mathie F, Swart F
PUBLIC SERVICE CO. OF COLORADO
To:
Shared Package
ML20086E183 List:
References
AO-50-267-74-4A, NUDOCS 8312060244
Download: ML20086E185 (4)


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April $I,1974 O ABNORMAL OCCURRENCE X FORT ST. VRAIN NUCLEAR GENERATING STATION PUBLIC SERVICE COMPANY OF COLO7uWO P. O. BOX 361 PLATTEVILLE, COLORADO 80651 REPORT NO. 50-267/74/4A Interitu X Final IDENTIFICATION OF OCCURRENCE:

This report is submitted to describe difficulties encountered in attempting to remove a modified manual retract tool from Control Rod Drive serial number 6 during SUT A-0.

This event is considered to be associated with the remedial action i suggested in Report of Abnormal Occurrence No. 50-267/74/4, submit.ted Feb-ruary 12, 1974.

l l CONDITIONS PRIOR TO OCCURRENCE: Steady State Power Routine Shutdown f ,

Hot Shutdown atoutine Load Change Cold Shutdown X Other (specify)

I? Refueling ' Shutdown - Initial cold physics tests -

Routine Startup in air.

8312060244 740610 PDR ADOCK 05000267 S PDR . _

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The major plant parameters at the time of the event were as follows:

Power PTR, N/A Wth ELECT, N/A We Secondary Coolant Pressure N/A psig Temperature N/A 'F Flow N/A #/hr.

Primary Coolant Pressure N/A psig Temperature N/A *F Core Inlet N/A 'F Core Outlet Flow _

N/A #/hr.

DESCRIPTION OF OCCURRENCE:

i During the 4:00 pm to midnight shift, April 19. 1974, Control Rod Drive serial number 6 was replaced in Refueling Region number 9 as a part of

,j Startup Test A-0.

The Control Red Drive :ns removed from region 9, using the special l

l Il bypass box and a manual retract tool, the day before, and had been stored in en equipment storage well awaiting reinstallation.

f When the Control Rod Drive was seated in the penetration, the special bypass box was connected and the drive-brake energized. At this point,

'i with the brakes holding the rods, it is normal to remove the manual retract tool. The tool, however, could not be removed, and appeared jammed with the manual retract gear.

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The Control Rod Drive was removed to an equipment storage well and other rods placed in the core in region 9.

The drive has not been disassembled to determine the cause of the binding.

APPARENT CAUSE OF OCCURRENCE: jDesign Unusual Service Cond.

Including Environ.

I Manufacture Component Failure Installation /Const. X Othar (specify)

Operator Unknown i Procedure ANALYSIS OF OCCURRENCE:

To be reported later.

! CORRECTIVE

! ACTION:

l To be decided later.

i FAILURE DATA /SIMILAR REPORTED OCCURRENCES:

No similar failures of this type-have been experienced.

PROGRA'.DIATIC IMPACT:

The loss of one Control Rod-Drive will not affect the program, but should the problem be generic, a tool rc-design may be required, which would delay the program.

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CODE IMPACT
None.

Prepared by: Approved:

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mbauv Frank M. Mathie FpdericE. Swart Maintenance Engineer Shperintendent

.' Fort St. Vrain Nuclear Fort St. Vrain Nuclear Generating Station l Generating Station I

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