ML20012A270

Provides Final Rept for Limited Exploration Program of ERCW Roadway Access Cells & Requests Extension for Completion of Pumphouse Foundation Program.Calculation for Foundation Investigation of ERCW Roadway Access Cells a & B Encl

ML20012A270
Person / Time
Site:	Sequoyah
Issue date:	03/01/1990
From:	Wallace E TENNESSEE VALLEY AUTHORITY
To:	NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
Shared Package
ML20012A271	List: ML20012A270 ML20012A303
References
NUDOCS 9003090117
Download: ML20012A270 (3)

Text

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TENNESSEE ViLLEt AUTHORITY l h -.

CH ATTANOOGA. TENNESSEE 374o1 =

0 SN 157B Lookout Place- )

E' WAR 011990 U'.S. . Nuclear Regulatory Comission '

ATTN: - Document Control Desk

' Washington D.C. .205SS

= Gentlemen:

'In the Matter of- ) Docket Nos. 50-327'  ;

Tennessee Valley Authority ) 50-328 j SEQUOYAH NUCLEAR PLANT (SQN) - ESSENTIAL RAW COOLING WATER (ERCW) PUNPHOUSE r FOUNDATION AND ERCW PUMPING STATION ACCESS CELLS o

Reference:

3TVA letter to NRC dated December 28, 1988, "Sequoyah' Nuclear Plant (SQN) - Essential Raw Cooling Water (ERCW) Pumphouse Foundation and ERCW Pumping Station Access cells"

.ThisLl etter provides the final report for the' limited exploration program of .  ;

the ERCW roadway access. cells-and requests an extension for the completion of the pumphouse foundation program.

'The enclosure'contains TVA: Calculation SCGlS299 for the foundation investigation.of ERCW Roadway Access Cells A and B. The conclusions of the  :

calculation are.that the structural integrity of the roadway access cells is '5

.roconfirmed..'the cells will perform their intended function under all design. 7, conditions,iand no additional investigation is necessary. These' conclusions

? were reported previously on an informal basis to Tom Cheng and Jack Donohew of

!~ your staff.

b Additionally, as discussed in a February 6, 1990, telephone conversation with Tom Cheng and Jack Donohew, TVA proposes to extend the completion of the pumphouse: foundation program to September.1, 1990. TVA has encountered difficulties in advancing the drill through the densely packed and/or partially cemented aggregate zones.. The logistics associated with the location-end security of the pump station also significantly increases the time required to get personnel, materials, and equipment into and out of the-

. pump station._ Finally, cold weather-has impacted the drilling and grouting

-since-insulating-or heating the water and grout hoses is not feasible.

To mitigate the effect on the schedule, a second drill rig and operator are being used for the program, and two shifts are being worked. The drilling and 1 grouting procedure has also been revised to allow additional flexibility in the sequence of drilling and grouting.

No voids, cavities, or loose aggregate pockets have been identified in the ,

pumphouse foundation holes completed to date. The voids reported from earlier r borings have been determined to be filled with densely packed and/or partially cemented aggregate. Interpretation of the data from the drilling, the 9003090117 900301 O '9 fDR ADOCK 05000327 PDC 6} 5 fi\

An Equal Opportunity Employer

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U.S. Nuclear Regulatory Commission downhole camera, and grout takes shows that.the condition of the foundation in

'the areas of potential concern is better than assumed in the restart i- evaluation.

As required by TVA's Commitment 3 in Enclosure 1 of the referenced letter, NRC's written concurrence with the schedule extension is requested.

No commitments are contained in this submittal. Please direct questions concerning this issue to Kathy S. Whitaker at (615)-843-7748..

Very truly yours, TENNESSEE VALLEY AUTHORITY E. G. Wallace, Manager Nuclear Licensing and Regulatory Affairs Enclosure cc:(Enclosure):

Ms. S. C. Black, Assistant Director for Projects -

TVA Projects Division U.S. Nuclear Regulatory Commission One White Flint,: North 111555 Rockville Pike Rockville, Maryland 20852 Mr. B. A. Wilson, Assistant Director E for Inspection Programs TVA Projects Division U.S.. Nuclear Regulatory Commission Region.II i

101 Marietta Street, NW, Suite 2900 Atlanta, Georgia. 30323 NRC Resident Inspector

-Sequoyah Nuclear Plant 2600 Igou Ferry Road Soddy Daisy, Tennesseo 37379 )

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' ENCLOSURE TVA CALCULATION SCGIS299

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