ML20085M582

AO 50-267/75/21:on 750911,control Rod Drive Inserted Into Pcrv Rotated 180 Degrees from Required Orientation During Control Rod Drive Mod.Caused by Design & Procedure Error. Procedures Modified

ML20085M582
Person / Time
Site:	Fort Saint Vrain
Issue date:	09/22/1975
From:	Hillyard H, Mathie F, Swart F PUBLIC SERVICE CO. OF COLORADO
To:	Howard E NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION IV)
References
AO-50-267-75-21, NUDOCS 8311090026
Download: ML20085M582 (6)

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o P. O. Box 361, Platteville, Colorado 80651 i

September 22, 19 T y

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C Mr. E. Morris Howard, Director r

Nucicar Regulatory Commission

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Region IV

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Office of Inspection and Enforcement f

Suite 1000 3)g.

Arlington, Texas 76012

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Reft Facility Operating License No. DPR-34 Docket No. 50-267 Dear Mr. Howard Enclosed please find a' copy of Abnormal Occurrence Report No. 50-267/75/21, 1

Final, subuitted per the requirements of the Technical Specifications.

Very truly yours, Frederic E. Swart Superintendent, Nuclear Production s

Fort St. Vrain Nucicar I.

Generatin's Station

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8311090026 750922 gDRADOCK 05000267 PM

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O REPORT DATE:

September l'8, 1975 ABNORMAL OCCURRENCE 75/21 OCCURRENCyDATE:

September 11, 1975 FORT ST. VRAIN NUCLEAR CENERATING STATION PUBLIC SERVICE COMPANY OF COLORADO P. O. BOX 361 PLATTEVILLE, COLORADO S0651 REPORT 540.50-267/75/21 Final IDENTIFICATION OF.

OCCURRENCE:

A control rod drive was inserted into the PCRV rotated 180* from its required orientation during the control rod drive modification (CWP-51).

This is identified as an abnormal occurrence per Section 2.1 (g) of the Fort St. Vrain Technical Specifications.

CONDITIONS PRIOR TO OCCURRENCE:

Steady State Power Routine Shutdown Hot Shutdown Routine Load Change X

Cold Shutdown Other (specify)

Refueling Shutdown Routine Startup The major plant parameters at the time of the event were as follows:

Power RTR 0

MWth ELECT 0

MWe

- f Secondary Coolant Pressure 250 psig Temperature 100

• F I

Flow 65,000 f/hr.

• Primary Coolant Pressure _

-0.1 psig If

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Temperature 98

• F Core Inlet y

100

• F Core Outlet.

s Flow 1

.'.tre. 0 4,000 r'pm 1

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ABNORMAL OCCURRENCE 75/21 Pags 2 of 5 e

DESCRIPTION OF OCCURRENCE:

The control rod drive for region 5 had been set in place, bolted down, rods inserted into the core, and the isolation valve removed from the reactor.

A mechanic was attempting to connect the helium purge and reserve shutdown pigtails (1/2" stainicss steel tubing) when trouble was reported. The re-fueling floor, supervisor was notified and he immediately noted the position of; the manus. rewind tool port in the rod drive was'not properly oriented in j

the penetration (see attached drawing) and concluded that the control rod drive had been inserted 180* from its required position.

APPARENT CAUSE 0F OCCURRENCE:

X Design Unusual Service Cond.

Including Environ.

Manufacture Component Failure l

_ Installation /Const.

Other (specify)

Operator X

Procedure The apparent causes of this occurrence are:

l.

Design - The keys on the control rod penetrations, are 180* apart.

There is nothing to prevent the control rod drives from being in-serted at 180* from its proper orientation.

2.

Procedure - The procedure in use did not require a check of the con-trol rod drive orientation prior to being lifted out of the equipment storage well by the auxiliary transfer cask.

ANALYSIS OF OCCURRENCE:

n The control rod drive had been removed from the PCRV and modified (reference Unusual Event No. 50-267/75/10). After cold checkout the drive was placed in an equipment storage well prior to reinsertion in the PCRV.

In the process of performing the modification to the control rod drive, it was rotated 180*.

Since the drive was placed in an equipment ' storage well rotated 180* out of proper orientation, it was returned to the PCRV 180* out of proper orientation because the equipment storage well dowels and auxiliary transfer cask rails maintain the same orientation during pickup.

The miscrientation of the control rod drive was realized when the workman attempted to reconnect the purge and reserve shutdown tubing. The stainless steel tubing is made to fit each individual. penetration but would not fit due to the improper orientation.. Although this 180* rotation did not affect the operation of the~ control rods, it did render the reserve shutdown inoperable because the reserve shutdo'wn tube was not mated to the reserve shutdown channel.

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Reserve NOTE 1: Control rod channels Shutdown are sy=etrical about Hole I

both axes.

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Control Control Rod Rod Channel _2 Channel 1 (Note 1)

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Reserve Shutdown guide TOP EW k

tube position with control COLUMN 1 M

rod drive installed 180' REGION 5 O

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ABNORMAL OCCURRENCE 75/21

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CORRECTIVE ACTION:

Procedures that deal with installing control rod drives in the reactor (CWP-51 and S0P 13-04) will be modified'to include a check of control rod drive orien-tation in an equipment storage well just prior to removal by the auxiliary transfer cask for return to the PCRV.

FAILURE DATA /SIMILAR REPORTED OCCURRENCES:

None PROGRAMMATIC IMPACT:

None CODE IMPACT:

Nonc Submitted By:

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__g liarvey. Ilillyard J r.

Technical Services Supervisor Reviewed By:

Frank M. Mathic Superintendent, Maintenance 7

Approved By:

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Fyederic E. Swart

%perintendent, Nuclear Production I