ML20056A415

Part 21 Rept Re Thomas & Betts Electrical Terminal Lug Cracking Around Barrel.Initially Reported on 900731.All Thomas & Betts Products Currently Stocked in Warehouses Isolated & Ordered Held in Warehouse

ML20056A415
Person / Time
Site:	Calvert Cliffs
Issue date:	08/03/1990
From:	Creel G BALTIMORE GAS & ELECTRIC CO.
To:	Office of Nuclear Reactor Regulation
References
REF-PT21-90 NUDOCS 9008070305
Download: ML20056A415 (4)

Text

-

. BALTIMORE GAS AND ELECTRIC CHARLES CENTER o P.O. BOX 1475 e BALTIMORE, MARYLAND 21203 1475 Gromot C. CRtti vict Pats ct=,

weit 6.t. .., August 3,1990 (300 tec ea66 U. S. Nuclear Regulatory Commission Washington,DC 20555 A'!TTNTION: Director Omcc of Nuclear Reactor Regulation

SUBJECT:

Calvert Cliffs Nuclear Power Plant Unit Nos.1 & 2; Docket Nos. 50-317 & 50 318 10 CFR Part 21.T&B Electrical Terminal Luc Material Deficiency Gentlemen:

Baltimore Gas and Electric Company hereby submits the attached report in accordance with the requirements of 10 CFR Pn " 21. 'Ihis condition was discussed with Region I staff on July 31,1990.  ;

Should you have any further questions regarding this matter, we will be pleased to discuss them with you.

Very truly yours, i

j

(

GCC/CDS/bjd 1

Attachment ec: D. A. Brune, Er.qu re J. E. Silberg. Esqui.:.

R. A. Capra, NRC l D. G. McDonut Jr., NRC T. T. Martin, NRC L. E. Nicholson, NEC ,

R. I. McLean, DNR '

pyl51 Y

>^,

.k 900807000?. 900s03 PDR i l S ADOCR 05000319 (

PDC

Cdvert Cliffs Nuclear Power Plant, Units 1 and 2 i Docket Nos.50 317 and 50 318 '

Page 1 of 3 ,

(1)

Name and Addnss ofIndividual Making Notification:

O " Crect,Vice President Nuclear Energy B ,umore Gas anr! Electric Charles Center i

P. O. Ikix 1475 Baltimore,MD 21203 (11) Hasic Comp < ment Affected: Cast Coppr Two llole Lug . IIcavy Duty 600V

• Catalog h umber $3212; Cable Size 4A) AWG Catalog Number 53210; Cable Size 2A) AWO 1

(111) Firms Supplying Component:

Supplier: Thomas and Betts (T&B) Corporation Electrical Division 1001 Frontier Road Brld cwater,NJ 08807 (201 685 1600 Fabricator: Unknown (iv) Natum of the Defect: The lugs tend to crack around the barrel when crimped which could cause disruption of power to certain safety related equipment. The cracks are randomly distributed throughout the crimped area and are wider, deeper, and more numerous than that which may normally be expected for lugs of this type.

Preliminary laboratory analysis indicates that the cracking was not due to improper crimping practices but was caused by improper manufacturing of the cast copper lugs. Thi copper was noted as being very brittle and having very large grain boundari<.,. These characteristics are usually associated with improper control l during c/ ting. ,

(v) Date On Which Defect Was identitled: The defect was first noticed on May 24, 1990 during a training class which involved the performance of example crimps for 4A) lugs. Members of the class noticed that some of the demonstration lugs exhibited the cracks after being crimped. A probicm report (PR 1826) was initiated. The Procurement Quality Unit placed all 4A) and 2A) lugs in the warehouse on hold. The warehouse was ordered not to issue or restock the item until the problern was resolved. A preliminary analysis was completed on July 27, 1990. The issue was determined to x reportable under Part 21 on July 30,1990.

(vi) Number And Imcation of Components: Currently all cast copper products ,

supplied by T&B are considered suspect to the problem. Based on preSr.iinary

testmg of other T&B products on site we feel that the extent of the defects are .

i limited to 2A) and 4A) lugs. We are taking steps, however, to gain a reasonable assurance that all T&B products at Calvert Cliffs are acceptable for their intended service. Calvert Cliffs has been using cast copper T&B lugs since April,1985.

Prior to that time we used Aluminum lugs.

Cah crt Cliffs Nuclear Power Plant, Units 1 and 2

' Docket Nos.50 317 and 50 318 Page 2 of 3 T&B sup plied the lugs to Calvert Clifts as commercial grade components. BO&E dedicatet the lugs as suitable for safety.rclated use based on internal dedication criteria. We currently know that at least two se aarate orders with defective 4M lugs (100 pieces per order) were received and det icated in 1989. We also have 69 2M lugs in stock. The lugs came from purchase orders in 1985,1987, and 1989 There is no traceability of any particular 1. ; to any particular purchase order so all are considered suspect components.

Our attempts at determining the total number of defective parts delivered has been hampered by a lack of available information from the supplier concerning material control and accountability in their manufacturing and distribution 3rocess. The supplier is a commercial grade vendor and lacks the documented nformation normally available from nuclear grade vendors to trace the material history of the components they supply.

(vil) Cornctive Actions Taken: Calvert Cliffs Units 1 and 2 are both currently shutdown. We are evaluatlog the defective lugs effect on operability of the  :

systems, structures, and components to which they are associated. We have I performed tests to determine the amount of force rec uired to pull a 4/0 AWO cable from the 4M defective lugs. Those tests incicated that the lugs are ocrforming much better than required to satisfy UL standards. Thus, it is our preliminary conclusion that the material defects do not significantly com?romise the mechanicalload carrying capability of the lugs. We also feel that the e cetrical load carrying capability of the lugs remains unaffected. This conclusion is based on the extent of overdesign, with res xet to load carrying capability, of the lugs.

We have noted no failures of the lugs n the pst.

Cortective actions which have been or will be completed include:

o All T&B products currently stocked in our warehouses were isolated and ordered held in the warehouse. These items will be released for i use only after a reasonable confidence is obtained that they contain no defects. All T&B products in the field that have not been installed have been recalled.

l o We are currently in contact with T&B to gain more knowledge about their material control processes and programs. We feel that this may help us to better " bound" the extent of the deficiencies and help us to assure that this deficicney is resolved in a safe and quality manner.

o We are currently in the process of determining the appropriate dedication criteria to identify future similar material deficiencies in electrical terminallugs.

o he testing of the lugs continues at our metallurgical laboratory.

Individual T&B types will be released for field use when they a.e shown to be acceptable, o Based on the results of the metallurgicallaboratory testing, we plan to '

develop inspection criteria for currently installed T&B lugs and specifications for when replaccment lugs are required to be installed.

I

Calvert Cliffs Nuclear Power Plant, Units 1 and 2

,' Docket Nos. 50 3i7 and 50 318 Page 3 of 3 o We ate currently in the process of identifying s l equipment that have suspect terminal lugs This installed.

is being pecific p; performed by a varicty> of methods including reviews of Maintenance Orders and Crimper Usage logs.

o We have initiated an INPO NUCLEAR NETWORK message to ,

notify other licensees of this material deficiency, We are in the process of revising the Field Inspection Criteria for o

crimps to include a visual inspection for t!'is type of cracking phenomena. We feel that this will be one of the most effective methods for futurt assurance that a lug is suitable for installation in the plant. ,

(vill) Other Adtke Related to Purchasers or Lkensees: None.

. - _ ~_