U-601463, Part 21 Rept Re Incorrectly Sized Stem Nut for Actuator of Anchor/Darling Gate Valve.Initially Reported on 890609.Stem Nut for Valve 1E22-FO15 Replaced

Part 21 Rept Re Incorrectly Sized Stem Nut for Actuator of Anchor/Darling Gate Valve.Initially Reported on 890609.Stem Nut for Valve 1E22-FO15 Replaced

ML20245F368
Person / Time
Site:	Clinton
Issue date:	06/13/1989
From:	Hall D ILLINOIS POWER CO.
To:	Davis A NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION III)
References
REF-PT21-89, REF-PT21-89-098-000 21-89-04, 21-89-4, DPH-0362-89, DPH-362-89, PT21-89-098-000, PT21-89-98, U-601463, NUDOCS 8906280119
Download: ML20245F368 (3)

Text

__

. , ) . .

U-601463

, L16-89 (06 -13 )-LP j 1A.120 l l

ILLIN0/S POWER OOMPANY CLINTON POWER STATION, P.O. BOX 678. CLINTON, ILLINOIS 61727 DPH-0362-89 June 13, 1989 10CFR21.21 Docket No. 50-461 Mr. A. B. Davis Regional Administrator Region III U.S. Nuclear Regulatory Commission 799 Roosevelt Road Glen Ellyn, Illinois 60137

Subject:

10CFR21 Defect 21-89-04:

Incorrectly Sized Stem Nut for Actuator of Anchor /Darlina Gate Valve

Dear Mr. Davis:

On June 7, 1909, Mr. J. S. Perry, Illinois Power Company (IP) Assistant Vice President, was informed of a 10CFR21 defect concerning a motor-operated Anchor / Darling valve that was delivered to Clinton Power Station with the actuator stem nut incorrectly sized. NRC Region III  ;

i management was verbally informed of this defect on June 9, 1989. Based on an evaluation of this matter for deportability under the provisions of 10CFR21, IP is providing the information listed below to the Commission in accordance with 10CFR, Part 21.21(b) (3) . Additionally, senior management review of this issue has determined that the investigation and deportability determination of the condition was not completed in an expeditious manner. To ensure that future Part 21 investigations and deportability determinations are completed expeditiously, the IP Part 21 procedure is being revised to add guidelines for duration of interim steps in the investigation and reporting process.

Additionally, key personnel will receive upgraded training on these changes and on the overall importance of the basis for the 10CFR21 reporting process.

(i) D. P. Hall, Senior Vice President of Illinois l Power Company, is informing the Commission of a 10CFR21 defect by means of this report, yfy6280119g99$33 e

hYD g ADOCK 05000461 PNU '

( , l 4' . w L U-301463 I L16-89 (06 - 13 ) -LP i

1A.120 I

(ii) The basic component involved in this reportable defect is valve 1E22-F015, a twenty-inch diameter motor-operated gate valve.

(iii) Valve 1E22-F015 was manufactured by the Anchor / Darling Valve Company for the General Electric Company for use in the High Pressure Core Spray System at Clinton Power Station.

1 (iv) The defect is an incorrectly sized stem nut. This

nut was installed during assembly of the motor-l operated valve to couple the stem of the valve to the Limitorque SB-1 actuator. Specifically, Anchor / Darling assembled the motor-operated valve using a two-inch diameter stem nut to couple the actuator to the one and three-quarter inch diameter stem of the gate valve.

1 IP has reviewed and evaluated the findings '

associated with this defect and has concluded that if this defect had gone uncorrected, the stem nut would have eventually failed because of the ,

minimum thread contact area with the valve stem i and the resulting high wear rate of the stem nut.

The failure of the stem nut would result in the inability to either remotely or manually stroke the valve. This failure would be significant to plant safety because valve 1E22-F015 performs active safesy functions in the opening and closing modes. A failure of valve 1E22-F015 to open would prevent High Pressure Core Spray System suction from the suppression pool. A failure of valve 1E22-F015 to close would prevent the valve from performing its containment isolation function.

(v) On April 8, 1989, while performing corrective maintenance on the Limitorque actuator of valve 1E22-F015, electrical maintenance technicians noted an unusual amount of brass flake build-up on t'.ne valve stem to stem nut interface.

Investigation of this brass flake build-up identified that the stem nut was badly worn.

Further investigation identified that the stem nut was not the correct size for the valve stem.

On April 11, 1989, a representative of the Anchor / Darling Valve Company confirmed that the threads of the stem nut were incorrectly machined for a two-inch diameter valve stem by j Anchor / Darling. 1 1

I

,f *

.]

U-601463 {

_ L16-89 (06 - 13 ) -LP i 1A.120 i

(vi) Based on information provided by the ,

Anchor / Darling Valve Company to IP engineering on '

April 20, 1989, two, twenty-inch diameter motor-operated gate valves manufactured for the General Electric Company could have been assembled with an incorrectly sized stem nut. One of these valves, 1E22-F015, was supplied to Clinton Power Station and the other valve was supplied to the River Bend Station.

(vii) The stem nut for valve 1E22-F015 was replaced with a stem nut of the correct size.in accordance with ,

maintenance work request (MWR) D05092. MWR D05092 )

was completed on April 14, 1989.

At this time IP is not aware of any other mot.or-operated valves that may be subject to the defect of an incorrectly sized stem nut. However, the Anchor / Darling Valve Company has indicated that they are investigating this defect to determine the extent of motor-operated valves involved. IP has requested that Anchor / Darling forward the results of their investigation to IP upon completion so that any additional affected equipment can be identified and corrected.

(viii) On April 20, 1989, IP verbally informed the River Bend Station that a motor-operated valve with an

-incorrectly sized stem nut may have been provided to them by the Anchor / Darling Valve Company. IP is also providing a copy of this report to the River Bend Station.

IP's evaluation of this reportable defect is available for your review at our offices. I trust this letter provides sufficient information for your review and assessment of this reportable defect.

Sincerely yours, D. P. Hall Senior Vice President RSF/dfd cc: NRC Resident Office ,

Director, Office of Nuclear Reactor Regulation I (3 copies)

INPO Records Center Illinois Department of Nuclear Safety ,

Senior Vice President, Gulf States Utilities i l

I