ML20024E255

Engine Systems, Inc., Submittal of Selenium Surge Suppressor, Emo P/N 8403049

ML20024E255
Person / Time
Site:	Point Beach, Surry
Issue date:	01/09/2020
From:	Wooland S Engine Systems
To:	Document Control Desk, Office of Nuclear Reactor Regulation
References
Download: ML20024E255 (6)

Text

• ~I. E~GINE SYSTEMS, INC: ..

• 175 Fretght Road ** . : .. Telephone: 2521977-2720 Ro<?i<Y Mount, NC *21804 .:  :* . Fax: 252/446-1134

" ~anuary 9, 202Q.

U.S. Nuclear Regulatory Commission* .*

DoGument Contru1 Desk ..

Washington,* DC 20555-000f.

_: subfect: 10CFR2*1 Reporting of Defects and Non-Compliance -

• Engine Systems; fnc. Report No. 10CFR21-0.1_28; ~ev. O Selenium *surge Suppressor, EMO P/~ 84:0~049

Dear Sir/ Madam:

The enclosed report 'addresses a 'reportable *notification- oh a selenium surge suppressor.,:EMD P/N 84p3049: **

A copy of the report has be~n .mailed to: our _affetjed . . nuclear customers ...

Ple~se sign below, ac~owledglng receipt of.this report, and return a copy to the atten~ion of Document Control at the address above (or, fax to number 252/446-1134) within 10 .working *days after: rE:l~.ipt. * \

• Y9urs.very truly, ENGINE SYSTEM$, .INC.

b~dJ~;e jj;E/9 Susan w.oolard

' Document Control

vi~

• * ' ' '

• I Please let us know If ANY of your malllng Information changes - name of recipient, name * **

of company/faclllty, .address, et~.. Mark the cha!'lges on this acknow.ledgrnent form. ~nd send to u~ by .mall or FA>(: to .ttl~ number a~ove: * ..

• RECEIVED:

93 ~ .. ---------

DATE:

Q*u*ality.Performan~ With Pride

ENGINE SYSTEMS, INC~ ..

175 Fretght Road, Rocky Mount, NC 27804 _ : Telephone': 252/977-2720

. Fax' 252/446-1134

• t*'

Report No. 10CFR21-0128 Rev. 0: 01/08/20

. i10CFR21 REPORTING OF DEFECTS

• I AND NON-COMPLl~.CE

'r .:.

COMPONENT: Selenium Surge Suppressor :* :* :

' P/N 8403049' * *. .* ' .

SYSTEM: Emergency Diesel Genera~or *

. ~ :

CONCLU$10N: Reporta~le in Accordance With 10CFR21 Prep~r~q By:--'-+--'~.___111 """"k,..__*

. C . . . . - - -_

• _

• _ _ _ _ __ Date:

• • ~gineering Manager Review~d.By:* _ _

__._a

__-_-Af;r ____.___~ _*______

.Quality Assurance Manager

• .. : Date: . /

r Jg-/::JOJO Quallfy: Performance Wi_th *Pride

Report No. 10CFR21-0128 Record of Revisions Page: 1 of 1 REV DATE PAGE DESCRIPTION 0 01/08/20 Initial issue.

C

Report No. 10CFR21 -0128 Revision: 0 Date: 01/08/20 Page: 1 of 3 Pursuant to 10 CFR 21.21(d)(4). ESI is presenting the required information as follows:

(i) Name and address of the individual or individuals informing the Commission.

John Kriesel Dan Roberts Engineering Manager Quality Manager Engine Systems Inc. Engine Systems Inc.

175 Freight Rd. 175 Freight Rd.

Rocky Mount, NC 27804 Rocky Mount, NC 27804 (ii) Identification of the basic component supplied with in the United States which fails to comply or contains a defect.

Selenium surge suppressor PIN 8403049.

(iii) Identification of the firm supplying the basic component which fails to comply or contains a defect.

Engine Systems Inc. (ES/)

(iv) Nature of the defect or failure to comply and the safety hazard which is created or could be created by such defect of failure to comply.

Three batches of selenium surge suppressors supplied by ES/ between 2011 and 2013 utilize a thread modification that is inadequate for the application. The design specifies the use of a single 1/4-20 x 2-314" long bolt to compress the stack of selenium cells as well as mount the suppressor (see Figure 1). Contrary to this requirement, the manufacturer used a #8-32 screw through the body of the stack and added a modified bolt to obtain the required 1/4-20 mounting threads. The modified bolt consisted of a 1/4-20 x 518" long bolt that was drilled and tapped in the head to accept

1. 8-32 threads. An attempt to install the selenium surge suppressor by tightening the co"esponding mounting nut may result in failure of the modified bolt threads. See photos 1, 2, & 3.

1/4-20 Bolt

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• H -- -- Figure 1: Outline Drawing of Selenium Surge Suppressor P/N 8403049 Photos 1, 2, & 3: Views of Suppressor with Modified Screw

Report No. 10CFR21-0128 Revision: 0 Date: 01/08/20 Page : 2 of 3 The selenium surge suppressor is a subcomponent of rectifier assembly PIN 8334736 (see Figure 2) used in the Vickers voltage regulator system. The rectifier assembly is shown as components CR1 through CR6 in Figure 3 and each function as a half wave rectifier, used in the static exciter, to furnish DC voltage for excitation of the generator field. The selenium surge suppressor protects the diode from surges by clamping at a voltage below the critical voltage for the diode, thus conducting around the diode at high energy levels.

. - - -- - - - - - -__.' Selenium Surge Suppressor '1--- - - - - - - - - - - ----,

P/N 8403049 ,

1------------------~--------

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I o~l~a-------<J~ -

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+

Figure 2: Rectifier Assembly P/N 8334736 (containing P/N 8403049)

Figure 3: Typical Vickers Voltage Regulator System Schematic

• Report No. 10CFR21-0128 Revision: 0 Date: 01/08/20 Page: 3 of 3 Use of this thread modifier significantly reduces the strength of the mounting threads. Failure of the mounting threads creates the possibility of the suppressor dislodging with the potential to electrically short between the positive and negative plates of the rectifier assembly. An electrical short would affect output of the voltage regulator system which may prevent the emergency diesel generator set from performing its safety-related function. This issue is therefore considered to be a reportable defect as defined by 10CFR-part 21 .

(v) The date on which the information of such defect or failure to comply was obtained.

November 14, 2019 (vi) In the case of a basic component which contains a defect or fails to comply, the number and location of these components in use at, supplied for, being supplied for, or may be supplied for, manufactured, or being manufactured for one or more facil ities or activities subject to the regulations in this part.

ESI Sales Description Customer Customer P.O. Qty C-of-C Date Order 3007242 00031254 3 01 -Nov-11 NextEra Energy - Point Beach Nuclear Plant Selenium Surge 3010498 02313190 1 01 -Mar-13 Suppressor P/N 8403049 Dominion Virginia Power - Surry Power Station 3011367 4500064790 24 27-Sep-13 (vii) The corrective action which has been, is being, or will be taken; the name of the individual or organization responsible for the action; and the length of time that has been or will be taken to complete the action .

For affected users:

• For surge suppressors installed, these are functionally acceptable but may be structurally compromised. The concern is the mounting nut may have unknowingly been tightened beyond the allowable strength of the bolt which could eventually cause the mounting system to fail. ES/

recommends inspection and/or replacement at the next opportunity.

• For surge suppressors not installed, ES/ recommends they be returned for replacement.

For ES/:

This part number has been discontinued and ES/ will offer new selenium surge suppressor PIN 8403049-ESI made by a different manufacturer but to the original drawing and design requirements.

Within the new dedication package, ES/ will include an inspection to verify the issue described in this report is not present. The time frame to source new suppressors and complete dedication activities is 12 weeks.

(viii) Any advice related to the potential defect or failure to comply about the facility, activity, or basic component that has been, is being, or will be given to purchasers or licensees.

NIA