ML20002D290
| ML20002D290 | |
| Person / Time | |
|---|---|
| Site: | Summer  |
| Issue date: | 01/16/1981 |
| From: | Nichols T SOUTH CAROLINA ELECTRIC & GAS CO. |
| To: | Harold Denton Office of Nuclear Reactor Regulation |
| References | |
| NUDOCS 8101200258 | |
| Download: ML20002D290 (3) | |
Text
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SOUTH CAROLINA ELECTRIC a GAS COMPANY
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cost omer son re4 COLUMBIA, SOUTH CAROLINA 292i8 T. C. NICHOLs, Ja.
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Mr. Harold R. Denton, Director Office of Nuclear Reactor Regulation l
-U. S. Nuclear Regulatory Commission Washington, D. C. 20555-
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Subject:
Virgil C. Summer Nuclear Station Docket No. 50/395 Service Water Line Survey
Dear Mr. Denton:
l Representatives from South Carolina Electric and Gas Company, I
Gilbert Associates, and Woodward-Clyde Consultants attended a meeting
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in Bethesda on November 19, 1980, with Messrs. Kane, Chen and Heller j
of the Staff to discuss issues surrounding the service water intake structure,pumphouse and associated connecting lines for the Virgil C.
1 Summer Nuclear Station. At that meeting the Staff requested that the
j service water intake lines from the service water pumphouse to the plant itself be surveyed to reconfirm its existing elevation for assur-ance that there had been no unanticipated differential settlement since its placement in 1978.
We have thoroughly evaluated several alternative methods to accom-j plish the survey. To minimize adverse effects on plant startup, unneces-l sary delays, damage to equipment and other existing facilities,along with re-testing and acceptance of these lines and still accomplish the re-verification of the elevation of these lines, South Carolina Electric l
and Gas Company proposes the following survey program. This program will i
provide adequate assurance that the service water intake lines are properly located and can safely perform their intended functions.
Brief Description of Service Water Intake Lines The service water intake lines convey cooling water from the service water pumps to safety systems and components necessary to achieve and main-tain a safe shutdown from normal plant operation or following a design basis accident. This system is composed of two 30" diameter steel (corrosion protected) pipes which are embedded in compacted select fill material and are located between the service water pumphouse and the diesel generator building (ref: Figure 21, Report No. 2, Service Water Intake Structure Settlement Effects and Related Work). These lines run east-west, are I
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Mr. Harold R. Denton Janua ry 16, 1981 Page Two Brief Description of Service Water Intake Lines (con't) 3'-6" center-to-center and are buried approximately 7' below the existing plant grade. The lines were originally placed to their design elevation under QC surveillance with a tolerance of 3" vertically. There are a series of flexible Dresser couplings on each end of these lines where they enter the buildings. There is a straight section on these lines in the plant yard area (approximately 320') which lies between the flexible Dresser couplings.
Proposed Survey of Service Water Intake Lines I
(A)
The two lines were placed under identical conditiens and are parallel to each other with a 3'-6" center-to-center spacing. Any settlement which has occurred since its installation would affect both lines equally. Thus, survey data for either line would be sufficient to determine if there was any settlement for either line. We therefore propose to survey the north line since the south line has other service lines running parallel to and directly above it.
(B)
We intend to survey only the approximately 320' straight section of line lying between the flexible Dresser couplings. The remainder of the line lies primarily under permanent pavement and contains a series of the flexible Dresser couplings which can accommodate large movements or deflections; therefore, these sections of line should not require investigation.
(C) of the 320' section of line, we plan to excavate along its length all sections which are not obstructed by roadways, duct banks, railroad tracks, piping, etc.
Survey data of the elevation of the top of the pipe will be made at approximately 5' intervals in the excavated sections.
It is estimated that approximately 55% of the 320' length will be accessible for survey. The largest section for which it is not feasible to survey is the approximately 60' length which is overlain by the electrical duct bank.
We feel this survey is a reasonable approach to provide positive assurance that no differential settlement has taken place sufficient to impose significant stress in the pipe. The survey data will be reviewed for its acceptability and a determination will be made if any additional investigation is required.
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Mr. Harold R. Denton January 16, 198?
.Page Three
. South Carolina Electric and Gas Company plans to proceed with this survey-by the end of January unless there are any further comments.
The results of this investigation will be submitted to you 'at the com-pletion of the survey and data analysis.
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Very truly yours, T. C. Nichols, Jr.
RBW:TCN:rh cc:
V. C. Summer G. H. Fischer T. C. Nichols, Jr.
E. H. Crews, Jr.
O. W..Dixon, Jr.
W. A. Williams, Jr.
O. S. Bradham D. A. Nauman R. B. Clary A. R. Koon A. A. Smith J. B. Knotts, Jr.
J. L. Skolds B. A. Bursey F. Waller.
I J. Lisney H. Radin S. Bailey J. Woods NPCF/Whitaker File l
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