ML20211D580

Concludes That Proposed Mods to Power Block Backfill Will Not Affect Category I Structures.Licensee Compaction Data Confirms Resolution of Sser 1,Item 6, Verification of FSAR Commitments..., Per Encl Evaluations of Submittals

ML20211D580
Person / Time
Site:	Vogtle
Issue date:	06/10/1986
From:	Mark Miller Office of Nuclear Reactor Regulation
To:	Conway R GEORGIA POWER CO.
References
NUDOCS 8606121036
Download: ML20211D580 (5)

Text

1 e l Docket Nos.: 50-424 and 50-425 10 JUN 1986 Pr. Richard Conway, Vice President and Project General Manager Georgia Power Company Box 299A Rt. 2 Waynesboro, Georgia 30830

Subject:

Transmittal of Evaluations of Modifications to Power Block Backfill and Category 1 Backfill Compaction Report By letter dated March 25, 1986, you discussed suggested modifications to the power block backfill. By letter dated April 4,1986, you proposed to dis-continue the evaluation of Category I backfill as required by SER confirmatory item 6 " Verification of FSAR commitments on compaction of Category 1 backfill," based on recent compaction data. The staff's evaluations of these submittals are contained in Enclosures 1 and 2, respectively. The staff has concluded that the proposed modifications to the power block backfill vill not have any affect on Category I structures and that the licensee's recent compaction data confirms the resolution of confirmatory item 6 in SSER 1 and that no further evaluation is necessary.

If there are any questions regarding these evaluations, contact me at (301)492-7357.

Sincerely,

\%

Melanie A. Miller, Project Manager PWR Project Directorate #4 Division of PWR Licensing-A

Enclosures:

As stated cc: See next page

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Docket Nos.: 50-424 end 50-425 Mr. Richard Conway, Vice President and Project General Manager Georgia Power Company Box 299A, Rt. 2 Waynesboro, Georgia 30830

Subject:

Transmittal of Evaluations of Modifications to Power Block Backfill and Category 1 Backfill Compaction Report By letter dated March 26, 1986, you discussed suggested modifications to the power block backfill. By letter dated April 4,1986, you proposed to dis-  ;

f continue the evaluation of Category I backfill as required by SER confirmatory item 6, " Verification of FSAR connitments on compaction of Category 1 backfill,"

based on recent compaction data. The staff's evaluations of these submittals are contained in Enclosures 1 and 2, respectively. The staff has concluded that the proposed modifications to the power block backfill will not have any effect on Category I structures and that the licensee's recent compaction data confirm the resolution of confirmatory item 6 in SSER 1 and that no further evaluation is necessary.

If there are any questions regarding these evaluations, contact me at (301)492-7357.

Sincerely,

~

i Melanie A. Miller, Project Manager PWR Project Directorate #4 Division of PWR Licensing-A

Enclosures:

As stated i cc: See next page l

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l Mr. R. E. Conway

1. Vogtle Electric Generating Plant Georgia Power Company cc:

Mr. L. T. Gucwa Resident Inspector Chief Nuclear Engineer Nuclear Regulatory Commission Georgia Power Company P. O. Box 572 P.O. Box 4545 Waynesboro, Georgia 30830 Atlanta, Georgia 30302 Mr. Ruble A. Thomas Deppish Kirkland, III, Counsel Vice President - Licensing Office of the Consumers' Utility Vogtle Project Council Georgia Power Company / Suite 225 Southern Company Services, Inc. 32 Peachtree Street, N.W. ,

P.O. Box 2625 Atlanta, Georgia 30303 -

Birmingham, Alabama 35202 James E. Joiner Mr. Donald O. Foster Troutman, Sanders, Lockerman, Vice President A Projett General Manager

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& Ashmore Georgia Power Company . Candler Building Post Office Box 299A, Route 2 127 Peachtree Street, N.E.

Waynesboro, Georgia 30830 Atlanta, Georgia 30303  ;

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Douglas C. Teper Mr. J. A. Bailey Georgians Against Nuclear Energy Project Licensing Manager 1253 Lenox Circle Southern Company Services, Inc. Atlanta, Georgia 30306 P.O. Box 2625 Birmingham, Alabama 35202 Billie Pirner Garde Citizens Clinic Director Ernest L. Blake, Jr. Government Accountability Project Bruce W. Churchill, Esq. 303 10th Street Shaw, Pittman, Potts and Trowbridge Augusta, Georgia 30901 1800 M Street, N.W.

l Washington, D. C. 20036

- Mr. G. Bockhold, Jr.

Vogtle Plant Manager Georgia Power Coinpany .

Route 2, Box 299-A ,

Waynesboro, Georgf.* 30830 Regional Administrator, Region II U.S. Nuclear Regulatory Conenission 101 Marietta Street, N.W., Suite 2900 Atlanta, Georgia 30323 I

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ENCLOSURE I

)

Evaluation of Proposed Modifications to Power Block Backfill By letter dated March 26, 1986, the applicant notified the NRC that it was reking minor modifications to the power block backfill. In this letter, the applicant stated that the top layers over the in-situ slopes forming the west side of the power block excavation and above elevation 206' will be backfilled with Category 2 material to 95 percent of the maximu'm density determined in accordance with ASTM D1557. This area was previously considered a part of the Category I backfill area. Review of the applicant's report showed that this area is remote from Category I structures, that it is above the water table and hence not subject to liquefaction, that it is not used to support Cate-gory I structures, and that it will not affect the foundations of Category I structures. Based on the information provided in this submittal, the staff agrees that these modifications are acceptable and that they will not have any affect on the foundations of Category I structures.

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k ENCLOSURE 2 Evaluation of Category 1 Backffil Compaction Report In SSER 1, the staff discussed the resolution of confirmatory item 6 regarding the adequacy of compacted densities for the Category 1 backfill because of the questionable appropriateness of using ASTM D1557 (impact compaction method) in laboratory testing to establish the maximum dry density for cleaner backfill sands. As part of the resolution of this issue, the applicant had comitted in its letter of August 12, 1985, to continue to increase the field laboratory-established maximum dry densities, when computing the percent compaction, as specified in SSER 1 and to provide the staff with a report which sumarizes and updates the compaction contrcl records for Category I backfill placed through December 1985. In SSER 1, the staff indicated that this issue was re-solved unless problems were encountered in meeting FSAR commitments on percent compaction of the Category 1 backfill placed since November 1984 as evidenced in the review of the applicant's report.

By letter dated April 4,1986, the applicant presented a report sumarizing the results of 2,795 tests perforced during the period of December 1984 to December 1985, and for 13,057 tests performed for the period of May 1980 to December 1985.

p Review of this information for the period of December 1984 to December 1985 i

. showed that the average compaction was 101 percent and that the average com-paction of all tests was 100 percent. The sumary showed thgt the evaluation was made by adding to the maximum laboratory densities 3.5 lb/fg for backfill which equaled or exceeded 6% passing the No. 200 sieve,3 4.51b/ft for backfill with less than 6% passing the No. 200 sieve, and 4.5 lb/ft when the percent passing the No. 200 sieve was unknown. Verification of the accuracy of this report was accomplished during onsite inspections while reviewing the applicant's Readiness Review Module 13A, " Foundation Materials and Backfill." During these inspections, the inspectors audited the applicant's test results for backfill materials placed between January 1984 and December 1985, and Calculations X2CF-S-11 and X2CF-S-117 which were completed to comply with the commitments made to the staff in response to SER confirmatory item 6. Review of these items showed that an average com-paction of 100 percent was indicated by the reevaluation program and that this method of reevaluation was conservative. Results of this reevaluation program of the backfill showed that Category 1 backfill meets the FSAR requirements.

In its letter of April 4, 1986, the applicant suggested that no further evaluation is required because (1) the Category 1 backfill is more than 95 percent complete and (2) the backfill which remains to be placed will primarily be in areas which do not support Category I structures. Based on review of the reevaluation program which confirms that the FSAR comitment for compaction of Category I backfill has been met, the staff agrees that no further evaluation is required and that the final resolution of confinnatory item 6, as discussed in SSER 1, remains unchanged.

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