ML20008G206

Part 21 Rept,Originally Reported on 790913,re Defective Topaz Inverters Mfg for Ge.Cause Unknown.Mod Kits Providing Ceramic Type Capacitors to Protect Against Line Transients Were Supplied by NSSS Vendor

ML20008G206
Person / Time
Site:	Grand Gulf
Issue date:	06/19/1981
From:	Mcgaughy J MISSISSIPPI POWER & LIGHT CO.
To:	James O'Reilly NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION II)
References
REF-PT21-81-456-000 10CFR-50.55E, 81-456, 81-456-000, AECM-81-164, PT21-81-456, PT21-81-456-000, NUDOCS 8107020445
Download: ML20008G206 (6)

Text

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l MISSISSIPPI POWER & LIGHT COMPANY

Helping Build Mississippi l

EmadMdednE P. O. B O X 1640, J AC K S O N MIS SIS SIP PI 3 9 2 05 l

aysy,;g,c,qyg.f e- 19, 1981 _

~9 /q l Office of Inspection & Enforcement g b .- --C d O U. S. Nuclear Regulatory Commission h

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(C Region II 101 Marietta Street, N.W.

C 17t v JUL 011981 m omme's

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Suite 3100 ,$.s.s. secue nsamana ,J. I Atlanta, Georgia 30303 i

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Attention: Mr. J. P. O'Reilly, Directo ' l' -

SUBJECT:

Grand Gulf Nuclear Station f Units 1 and 2

-(D - Y Docket'Nos. 50-416/417

.h O ~ p / File 0260/15525/15526 PRD-79/17, Final Report, Defective Topaz Inverters AECM-81/164

References:

1) AECM-79/1'16, 10/16/79 ' '

2) AECM-80/32, 1/31/80

3) AECM-80/103, 5/15/80

4) AECM-80/192, 8/18/80

5) AECM-80/297, 12/1/80

6) AECM-81/121, 3/25/81 On September 13, 1979, Mississippi Power & Light Compeny notified Mr. J.

C. Bryant, of your office, of a Potentially Reportable Deficiency (PRD) at the Grand Gulf Nuclear Station (GGNS) construction site. The deficiency concarns defective inverters manufactured by Topaz Electronics for equipment supplied by General Electric. This deficiency has been previously reported under the.

meaning.of 10CFR50.55(e) in Reference 2 above. We have now determined that this deficiency is also reportable under the provisions of 10CFR21.

We have determined that the GE modification plan to provide capacitance l

on the inverter input is accaptable as a permanent resolution to this problem.

I Attached is our final report to PRD-79/17.

l Yours truly L--

g y J. P. McGaughy, Jr.

KDS:dr Attacha nt cc: See page 2 fN

$Il 4, ,!8t1M.O.LQO -

M' ember Middle South utilities sys sm /CY S __

i Mr. J. P. O'Reilly AECM-31/164 NRC Page 2 cc: Mr. N. L. Stampley Mr. R. B. McGehee -

Mr. T. B. Conner Mr. Vi'etor Stello, Director Office of Inspection & Enforcement U. S. Nuclear Regulatory Commission ,

Washington, D.C. 20555 Mr. G. B. Taylor South Miss. Electric Power Association P. O. Box 1589 -

Hattiesburg, MS 39401 O

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Dr. D. C. Gibbs Mr. D. C. Lutken Mr. J. N. Ward Mr. W. A..Braun Mr. R. Trickovie Mr. J. W. Yelverton Mr. L. F. Dale Mr. C. K. McCoy Mr. T. H. Cloninger Mr. R. A. Ambrosino e Mr. R. C. Fron

, Yr. G. B. Rogers

! Mr. M. R. Williams l , Mr. L. E. Ruhland i Mr. D. L. Hunt -

l Mr. A. G. Wagner Mr. P. A. Taylor PRD File .

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Attachment to AECM-81/164 Page 1 of 3 FINAL REPORT FOR PRD-79/17 REPORTABLE UNDER 10CFR50.55(e) AND 10CFR PART 21 L _

1. Name and address of the individual... informing the commission:

T.'E. Reaves, Jr.

Manager of Quality Assurance '

P.O. Box 1640 j

Jackson, Mississippi 39205 1

Notification of Part 21 applicability made to Mr. Pete Taylor, NRC, 7

Region II, at 3:55 PM June 19, 1981. -

2. Identification of the facility...which. . .contains a defect:

! Grand Gulf Nuclear Station (GCNS) Units 1 & 2 i Port Gibson, Mississippi 39150 -

3. -Identification of the firm... supplying the basic component which...

contains a defect:

Supplied to Grand Gulf by the General Electric Company, San Jose, California. GE obtained them from Topaz Electronics, San Diego, California.

4. Na ture of the defect...and the safety hazard which... could be created by such defect...:

A. Description of the Deficiency Topaz inverters are used to supply essential divisional power from station batteries to the Emergency Core Cooling Spray (ECCS) transmitters / trip unit analog sensors. The Model GZ inverter has l been found to fail because of transient signals such as those gene-l rated on the 125 volt DC bus from switching relay coils. High frequency voltage spikes can be generated in the DC system. This

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could lead to 'a blown fuse and a failed Silicon Control Rectifier (SCR) on one or more Topaz inverters.

l Inverter failure could prevent the initiation of the ECCS. The

. Model GZ inverter in question is used on GE supplie. equipment on both Units 1 and 2.

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Our Architect / Engineer has also determined that Topaz Model GZ in-verters were used _n some non-NSSS systems, but it has been deter-mined that they were not used in control circuitry involved in safe shutdown or accident mitigation.

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Atttchm2nt to AECM-81/164 Page 2 of 3 l

B. Analysis of Safety Implications The Topaz Inverter Model GZ is used to supply essential divisional power from station batteries to the Emergency Core Cooling Spray transmitters / trip unit analog sensors. In a normal operating condi- -

tion, the loss of an ECCS system inverter /SCR would be covered by the other redundant system. However,- if all inverters /SCR's failed, this would prevent automatic Energency Core Cooling Spray initiation, j thus affecting adversely the safety of operations of the plant. ,

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This' deficiency had previously been determined to be reportable within the meaning of 10CFR50.55(e) and was reported as such in AECM-80/32, January 31, 1980. Mississippi Power & Light Company has now deter-l mined t'. tat this condition is also reportable under the provisions of i 10CFR21.

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5. The date on which the information of such defect... was obtained.

The deficiency was originally identified and reported to Mr. J. L. Crews of the Region V, Nuclear Regulatory Commission under the provisions of 10CFR21 by General Electric on September 5,1979.

l After receipt of a copy of GE's letter to the NRC, Mississippi Pownr &

Light Company reported the deficiency to Mr. J. C. Bryant of your office as a Potentially Reportable Deficiency on September 13, 1979. Since that

date, MP&L has filed six (6) interim reports to inform the Commission of the progress and status of this deficiency. An evaluation for Part 21 has been completed and the MP&L " Responsible Officer", Mr. J. P. McGaughy, Jr.,

has been notified.

- 6. In the case of the basic component... the number and location of all such components.

The Topaz Model GZ Inverter in question is used on General Electric sup-Our Architect / Engineer has also plied equipment on both Units 1 and 2.

l determined that the same model inverters were used in some non-NSSS l systems, but is has been determined that they were not used in control

( circuitry involved in safe shutdown or accident mitigation.

! We do not have knowledge of the location of defective equipment located othes than GGNS.

l 7. The corrective action which has been taken. .. .the name of the individual...

l responsible for the action; and the length of time that has been...taken to complete the action.

A. Corrective Actions Taken This deficiency will be corrected by our NSSS supplier providing kits for implementation into the circuits at GCNS. These kits will provide ceramic type capacitors on the inverter input to protect the devices from the line transients. GE has written Field Disposition e b, e tf '  %  % 84 4 'n* I ' Y* I '

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Atttchment to AECM-81/164 Page 3 of 3 Instructions for the installation of the modification kits for Unit 1 and Unit 2 at Grand Gulf Nuclear Station. Since all deficient safety related Topaz Inverters c.t GGNS will be modified, recurrence of the deficiency will not occur. _

MP&L's engineering organization has completed their evaluation of the modification kits and the corrective action taken by GE and concurs that this modification is an acceptable permanent "fix".

l B. Responsible Individual l

G. B. Rogers, Jr.

l l Site Manager Mississippi Power & Light Company .

C. Length of Time to Complete Actions The problem was identified in September, 1979. General Electric -

issued Field Disposition Instructions WAMX (Unit 1) and WBJF (Unit

2) to the GGNS site in July, 1980. Work *on WAMX was completed on April 23, 1981. Work on WBJF will begin when work is resumed on Unit 2 at GGNS.

8. Any advice related to the -defect... that has been, is being, or will be given to purchasers or licensees:

As the deficiency did not originate with MP&L, we have no advice to -

offer. ,

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