IR 05000498/1983026

Testimony of Ji Tapia Re Safety Significance of Two Violations in Area of Soil Discussed in Insp Repts 50-498/83-26 & 50-499/83-26.Related Correspondence

ML20127N101
Person / Time
Site:	South Texas
Issue date:	06/28/1985
From:	Tapia J NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION IV)
To:
Shared Package
ML20127N039	List: IR 05000498/1983026 ML20127N036 ML20127N064 ML20127N082 ML20127N125 ML20127N141 ML20127N146 ML20127N149 ML20127N153 ML20127N162 ML20127N168 ML20127N172
References
OL, NUDOCS 8507010432
Download: ML20127N101 (6)

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USNAC 85 JJN 28 P1:43 UNITED STATES OF AliERICA c,rr;cE OF SECht'M NUCLEAR REGULATORY COMMISSION 00C8ETiNG A SERVW BRANCH BEFORE THE AT0f11C SAFETY AND LICENSING BOARD In the flatter of HOUSTON LIGHTING AND POWER COMPANY, Docket Nos. 50-498

_ET _A_L (South Texas Project, Units 1 & 2) )

Testimony of Joseph I. Tapia Please state your name, business address, employer and titl My name is Joseph I. Tapi I am employed by the U.S. Nuclear Regulatory Commission as a Reactor Inspector. My business address is 611 Ryan Plaza Drive, Suite 1000, Arlington, Texas. A statement of my professional qualifications is attache Have your professional qualifications been admitted to this proceeding previously? Yes, My professional qualifications appear following Tr. 9126, ff, p. 6 Are there any changes you wish to make with respect to those qualfications?

0507010432 850626 PDR ADOCK 05000498 T PDR ,

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A. N Q. What is the purpose of your testimony?

A. The purpose of my testimony is to report on the safety significance of the two violations in the area of soils discussed in NRC Inspection Report No.83-26(datedApril 20,1984) and on findings 23 and 24 of the programmatic audit, conducted as a result of the NRC Report, which was filed by HLAP on May 25, 1984 (ST-HL-AE-1095). Specifically, I will report on whether there is reasonable assurance that the backfill placed by Ebasco at the STP is in conformity with the design requirements of the construction permits and NRC regulation Q. Please describe your responsibilities with regard to this inspection report and the programmatic audi A. I was responsible for identifying and documenting the two violations described in NRC Report 83-2 I was also responsible for evaluating findings 23 and 24 of the programmatic audit filed by HL&P on May 25, 198 Q. Please provide your assessment of the safety significance of each of the violations in Report No. 83-2 A. The first violation relates to a deviation from the American Society for Testing and Haterials (ASTM) standard for determining the minimum density

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of backfill. ASTM standard D2049-69, " Relative Density of Cohesionless Soils," requires that a funnel pouring device be used in the minimum density test for backfill samples having a maximum size of soil particle of 3/8 inch. The backfill size used at STP meets this requirement; however, Bechtel, by letter dated April 6,1983, directed Pittsburgh Testing Laboratories (PTL) to modify its test procedure to implement the use of a scoop in lieu of the required funnel pouring device. The change to the scoop resulted in lower values of minimum density which in turn made it easier to satisfy the field requirement for minimum percent compaction. Due to the mechanics of using a scoop rather than a funnel-pouring device, less density occurs in the test sampl In response to this finding, the effects on relative density measurements of both techniques for determining minimum density were quantifie It was determined that the funnel method yielded relative density measurements that were from 4 to 6 percent lower than the scoop metho All affected relative density test values were recalculated after incorporating the reduction in relative densities which would have resulted from the use of the more conservative funnel method. Of 1135 test values,183 were found to be below the 80 percent minimum relative density criteria for Category I structural backfill and 4 were found to be below 70 percent. None of the lower than specified test values were located directly below any structure. This point is important in that the 80 percent criteria was primarily established to provide foundation support characteristics which include bearing capacity, cyclic strength, dynamic shear modulus and damping rati .

-4-For backfill not beneath a building, the most important consideration is whether the material may liquify during a seismic event and potentially adopt a fluid behavior. The four tests below 70 percent are located near the surface and away from any structure. These represent the lowest density measurements. The minimum factor of safety against liquifaction after correction for the scoop method was found to be above 1.7 for all test location This is an acceptable margin of safety against liquification. The lower than specified relative densities are randomly located and contained within denser materia Based on these factors, it is my belief that the deviation from the ASTM standard does not represent a significant degradation in the quality of the backfill material and therefore does not represent a reduction in the safety of the plan The second violation pertained to Ebasco's Quality Control procedure for the inspection of backfill. The procedure only required the monitoring of backfilling operations on a daily basis. Based on ny review of the number of in-place density tests which had to be re-run, I felt that the monitoring requirement was weak in that such a monitoring frequency did not result in sufficient compactive effort prior to in-place density

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testin In addition, as a result of daily basis monitoring, only one inspection form was generated each day and it was found to be inadequate in that the specific locations of the QC inspections could not be determine In response to my observations, the QC procedure was changed to provide increased inspection verification and documentation. The NRC resident

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inspector, Donald Garrison, reviewed this item and closed it in Inspection Report No. 85-04 The technical significance of my observation is minor

. in that, although the procedure was weak, QC inspection was occurrin i' ore importantly, however, the acceptance of the backfill material was based on the in-situ testing of the compacted backfill. Test locations were selected in an unbiased manner and gave a representative sample of field condition It is my belief that the backfill placement was systematic as interpreted with engineering judgment that considers the properties of the backfill material, the construction process, and the in-place density test result _ Please provide your asseisment.of the safety significance of findings 23 and 24 of the prtigrammatic audi _

, Findingy23 states that,the sofis inspection procedure did not provide

criteria for[derisity testing depth and finding 24 notes that the procedure

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did not requi the test elevation to be recorde In response to these

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findings, the 'rocedure p was revised to~ adopt depth criteria and to require that test elevations 'be recorde'd. The FSAR was revised in Amendment 38 to

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indicate thatt" tests Ere selected such that they give representative

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,, y, density inforcation far'all lifts within the fill." These findings are

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repetitions of Noncompiiance No. 4 in NRC Report No. 79-19. The test of

. backfill left the_ selection of the depth to the judgment of the inspector who usually redoved loose material until a level, smooth, firm surface was obtained. Such a testing technique was observed by myself and I found it p ..

. to be satisfactory. The fact' that depth critoria did not exist and

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documentation was not occurring is of minor significance as was previously determined in my review of the response to Noncompliance No. 4 (which I closed out in NRC Report No. 80-17). Nevertheless, both findings have been incorporated into the test procedur Q. ' Is there reasonable assurance that the backfill placed at STP by Ebasco is in conformity with appropriate design requirements of the construction permits and Commission iogulations? Ye Based on my review of the responses to the subject violations and audit findings, in my opinion, these represent minor conditions that have not impacted the adequacy of the backfill material.

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