ML19294B485

Final Deficiency Rept Re Electrical Conduit Supports Attached to Concrete Structures W/Anchor Bolts That Did Not Meet Tolerance Criteria.Engineering Change Implemented to Include Tables Developed in Specs.Supports Being Repaired

ML19294B485
Person / Time
Site:	Summer
Issue date:	02/11/1980
From:	Crews E SOUTH CAROLINA ELECTRIC & GAS CO.
To:
References
NUDOCS 8003030458
Download: ML19294B485 (2)

Text

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SOUTH CAROLINA ELECTRIC & gas COMPANY post onica som re.

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mes Pension v ..o Gaove tascume c u o c..... cri 7 February 11, 1980 Ly ,_

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Mr. James P. O'Reilly, Director .. ]

United States Nuclear Regulatory Commission e_

Region II, Suite 3100 c/

101 Marietta Street, N. W.

Atlanta, GA 30303

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Subject:

Virgil C. Summer Nuclear Station, Unit 1 Reportable Significant Deficiency Nuclear Engineering File 3.1051

Dear Mr. O'Reilly:

On February 4,1980, a significant deficiency was reported to Mr.

Jack Skolds, NRC resident inspector, by Mr. J. A. Wactor of SCE&G. The deficiency involved electrical conduit supports that were attached to concrete structures with anchor bolts. These supports were required to be installed with certain tolerances so that an additional force would not be exerted on the anchor bolts if the conduit was forced inte place.

The deficiency was discovered when field personnel complained about the tolerance imposed and claimed it to be impractical to meet. The original tolerance specified that the supports in the same plane be within 1/4 of an inch. This requirement did not take into account possible bends in the conduit or bends at joints and would require surveyor type instruments to verify.

Since the problem was actually one of limiting the " cold spring" of the conduit and not getting the supports straight, the specifications were changed to measure the offset of the conduit rather than alignment.

Also, the amount of " cold spring" allowable was broken down for each size conduit and produced in a table. When this was done, it was discovered that the larger conduits could not be allowed 1/4" of cold spring.

After more study it was realized that the cold spring criteria should also include supports around a bend in the conduit. An investigation was made on the installed conduit in which supports were loosened and the cold spring measured. A total of 71 conduits were found with supports that did not meet the criteria. Some of these conduits were mutually redundant. If this deficiency had gone undetected, the deficient supports could have failed during a seismic event causing loss of redundant functions. Therefore, the deficiency is considered reportable under 10CFR50.55(e). jpg/9 65

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s Mr. James P. O'Reilly Page 2 February 11, 1980 Corrective action consists of an engineering change to include the tables developed in the specificatio'a,and epair of the deficient supports by shimming or rework. This is now in pr gress. Based on the actions described above, this is considered to be fidal report on the item.

i ery ruly yours,

. . Ctews, Jr.

JAW:rm

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