ML19263B925

Formal Rept Per 10CFR50.55(e) Re Apparent Inadequate Bolting Design for 2 Emergency Diesel Generator Exciter Cubicles. Seismic Test Review Found Hold Down Bolting Inadequate,Due to Incorrect Vendor Drawings & No Interface Review

ML19263B925
Person / Time
Site:	Summer
Issue date:	12/22/1978
From:	Mary Johnson SOUTH CAROLINA ELECTRIC & GAS CO.
To:	James O'Reilly NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION II)
References
NUDOCS 7901250147
Download: ML19263B925 (3)

Text

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O I $$5 j;> El5 SOUTH CAROLINA ELECTRIC a GAS COMPANY r .o., o ,,a . o . s . .

COLumalA, SQUTH CAROUN A 29218 M.C. JOHNSON

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December 22, 1978

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United States Nuclear Regulatory Commission ATTN: Mr. James P. O'Reilly Director Region II - Suite 1217 230 Peachtree Street, Northwest Atlanta, Georgia 30303 Re: V. C. Suncer Nuclear Station Unit #1 Reportable Items in Accordance with 10CFR50.55(e)

Centlemen:

On November 23, 1978, SCE6C identified to Region Il apparent inadequate bolting design for two (2) emergency diesel generator exciter cubicles.

The purpose of thin letter is to provide our formal report on this matter and to update the status of previous reportable items.

During a review of the seismic tests for the exciter cubicles, it was discovered that the hold down bolting which was shown on design drawing;s would not adequately carry the necessary loads which would occur during the design basis event. It has been shown that failure of the hold down bolting could have resulted in loss of power f rom the emergency generators.

Inadequate design of the subject bolting resulted due to the following:

1) Vendor drawings which did not specify bolting material and torquing requirements as required by the specification (SP-546); 2) Lack of inter-face review of drawings by proper design engineers; 3) Detailing of bolting (size and material) by ot her than proper design personnel; i.e.

electrical draf ting personnel revised design drawings to show above h" Nelson Studs or equal.

Immediate corrective action includes issuance of a Corrective Action Request to Colt Industries relative to their failure to comply with the specification and re-evaluation of the foundation hold downs resulting in a design which will carry the loads imposed by the seismic event.

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3 Mr. James P. O'Reilly Page 2 Dec, ember?22, 1978 Further long term corrective action will include 1) additional indoctrination of project design engineers as to proper implementation of interface deeign reviews and design responsibilities; and 2) review by project s tructural engineer to investigate equipment anchorages of seismic Category I electrical equipment.

Subsequent to discovery and raporting of this deficiency, an audit was performed on December 13-15, 1978, by SCE&G/QA on our Architect /Engineet.

During that audit, the subject hold down bolting problem was forther investigated and documented. An audit finding was generated relative to the design control aspects of this problem and incluaed recommendations for indoctrination as indicated above. This finding will be closed out after proper and complete corrective action by the Architect / Engineer has occured. We consider the above information our final report on this item.

As an update of our September 29, 1978 letter to you, we would like to appraise you of the current status of the items there-in discussed.

1. Pipe Whip Rupture Restraints _ - Continuing investigations of the problem encountered revealed that the condition was caused by the facts previously transmitted in our letter of August 14, 1978. The repair program instituted at that time is virtually complete and SCE&G/QA has verified via the audit of the Architect / Engineer mentioned above, appropriate design control program elements were exercised during the establishment of the examination criteria for the repair program.

SCESG/QA established resident surveillance at APCO from mid September until December 1, 1978, at which time surveillance of APCO resorted again to an as needed basia. During this period, the surveillance representative verified that required UT, grind out, MT examination, reweld, sample UT of repaired restraints, and subsequent preparation for return to the V. C.

Summer Station were performed adequately. Documentation associated with the rework of restraints was compiled by APCO, examined by the SCESC/QA representative and transmitted to the V. C. Summer Station with shipment of restraints to supplement original docu-mentation.

As a result of the above actions, SCE&G has cenfidence that accepta-ble restraints are now at the construction site, and considers that potential affects on the safety of operations of the plant under pipe rupture conditions have been climinated. SCESG considers action on this item complete.

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3 Mr. James P. O'Reilly Page 3 DecembeF 22, 1978

2. Rockwell Valve Operator Q_ualification - Rework cf all affected actuators is complete at Rockwell. Final testing and shipment is anticipated in January. As was discussed with Region II on December 1, 1978, efforts in relation to evaluation of Rockwell procurement control have established that inadequate QA controls were imposed by contract on the Rockwell supplier of limit switches (Namco) and that insufficient objective evidence exists in the Namco QA Program to confirm manufacturing repeatability of the switches. However, based on direct discussions with Namco, a testing program has been formulated which SCE6G/QA believes,1f successful, will establish the repeatability of the process control system imposed. Ef forts are now in process to have this testing program implemented for limit switches on SCE&G valves.

3. Emergency Diesel Generator Deficiencies - Fuel lines on the Summer diesels have been replaced and the removed units taken by the field representatives. Discussions with the supplier on 12/20/78, confirmed that a letter would be transmitted indicating the results of the supplier evaluation of the fuel lines. A SCESG/QA release to work for injection pumps, and exhaust rocker arms was transmitted to the supplier on 12/18/78. Release of lube oil header examina-tion is pending. Results of inspections of these items by the supplier will be reported to SCESG. We understand that the supplier has kept the NRC abreast of generic status through the Region III office.

In summary, we consider this letter the final report on two items as indicated above. You may be assured that we will continue to work toward the complete resolution of the remaining items.

Please feel free to contact me if you have any questions or desire clarification of any information contained in this report.

Very truly; ours,

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DAN /MCJ/jls cc: C. J. Fritz G. C. Meetze Office of Director of Inspection & Enforcement U. S. NRC Washington, D. C. 20555 I2