ML20215J702

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Comments on 870413,14 & 0508 Util Ltrs Re Proposed Revs to FSAR Sections 2.5.4.6.2, Groundwater Control Criteria & 2.5.6 Embankment Settlement. Concludes That Changes Should Not Affect SER Conclusions Previously Reached
ML20215J702
Person / Time
Site: South Texas  STP Nuclear Operating Company icon.png
Issue date: 06/18/1987
From: David Wright
ARMY, DEPT. OF, CORPS OF ENGINEERS
To: Pichumani R
Office of Nuclear Reactor Regulation
References
CON-NRC-03-82-102, CON-NRC-3-82-102 NUDOCS 8706250082
Download: ML20215J702 (2)


Text

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'k DEPARTMENT OF THE ARMY '

SOUTHWESTERN DIVISION, CORPS OF ENGINEERS 1114 C O M M E R C E ST R E E T D ALLAS. TEXAS 75242 0216 MEE - 18 JUN 1987 Geotechnical and Materials Branch Mr. Raman Pichumani i United States Nuclear Regulatory Commission Structural and Geosciences Branch Division of Engineering and Systems Technology Washington, D.C. 20555  !

Dear Mr. Pichumani:

Please reference our telephone conversation on May 22, 1987 )

and your letter dated June 1, 1987, subject: South Texas Project -!

- Safety Evaluation Report (Interagency Agreement No. NRC-03 102, Work Order No. 5).

I have reviewed the information in three letters (dated April 13, 1987, April 14, 1987 and May 8, 1987) from Houston Lighting &

Power Company (HL&P) which deal with proposed revisions to FSAR Section 2.5.4.6.2 (Groundwater Control Criteria) and FSAR Section  ;

2.5.6 (Embankment Sett,lement). My comments are as follows:

a. . Letter dated April 14, 1987 - FSAR Revisions Concerning ,

Section.2.5.6: EAb3_rthmentt_S_ettl ement The Essential Cooling Pond (ECP) is a low, relatively flat sloped embankment constructed primarily of select clay fill and protected with either reinforced concrete or soil cement.

Some of the estimated ultimate settlement occurred during con-struction - the remaining long term settlement will occur over a period of years. The low, clay filled embankment is sufficiently flexible to withstand settlements of 2 to 4 inches. Concur that the increase in the estimated ultimate settlement will not affect the integrity of the ECP embankment,

b. Letter dated April 13, 1987 - FSAR Revision Concerning'

-Section 2.5.4.6.2; Groundwater Control Criteria and Letter dated .,k May 8, 1987 - Supplemental Information Regarding ,

GI911ndWattar_Anntrol Clllarin The excavations involve only non-Category I, secondary lightly loaded structures. During excavations, the watertable will be monitored and, if required, a local dewatering system will be installed to maintain the groundwater table 2 feet below the bottom of the excavation.

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i For these conditions, concur that " Raising the piezo-metric surface from 5 feet below the bottom of an excavation to 2 feet below the bottom of an excavation has no effect on sub-sequent factors of safety after the foundation is completed and the excavation has been backfilled." Likewise, concur that these changes should not " affect conclusions previously reached in the South Texas Project SER."  :

If I can be of any further service, please call me at FTS 729-2377. 1 Sincerely, thus -

David E. Wrig ., P.E.

Civil Engineer Geotechnical and Materials Branch i

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