ML20093M823

Forwards geotechnical-related Questions Pertaining to FSAR, Vols 1-16 & Responses to NRC Questions,Vols 1 & 2

ML20093M823
Person / Time
Site:	South Texas
Issue date:	10/19/1984
From:	Denys A ARMY, DEPT. OF, CORPS OF ENGINEERS
To:	Heller L Office of Nuclear Reactor Regulation
References
CON-NRC-03-82-102, CON-NRC-3-82-102 NUDOCS 8410230309
Download: ML20093M823 (7)

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t 10 p\g DEPARTMENT CF THE ARMY SOUTHWESTERN DIVISION. COCPS OF ENGINEERS

• - F 1114 COMMERCE STREET DALLAS, TEXAS 75242-0216 REPET TO ATTENTION OFs Engineering Division Geotechnical and Material Branch

[f)- kTY kSf Dr. Lyman Heller U.S. Nuclear Regulatory Commission Office of Nuclear Reactor Regulation Mail Stop P-214 Washington, DC 20555

Dear Dr. Heller:

Please reference Interagency Agreement (IA) No. NRC-03-82-102; Work Crder No. Five (5), South Texas, Units 1 and 2. Attached as Eu i ure 1 is a list of geotechnical related questions pertaining to the South Texas Project Final Safety Analysis Report (Volumes 1 through 16 and Responses to NRC Questions Volume 1 and 2). Responses to many of the questions may be contained in the requested references shown on Enclosure 2. The Project and Financial Status report is at Enclosure 3.

As a part of this work order, we are required to prepare a draft Safety Evaluation Report (SER) and SSER. Please provide any standard formats, requirements, instructions, etc. for preparation of these documents. We would also like to make a visit to the site at your earliest convenienet.

If you have any questions, please contact David E. Wright (FTS 729-2377, commercial 214-767-2377).

Sincerely,

, k

/ Arthur D. Denys, P.E.

Chief, Engineering Division Enclosures Copy furnished:

DAEN-ECE-G, ATTN: Mr. Dale Munger U.S. Nuclear Regulatory Commission Contracting Officer, DC Director, Division of Engineering, ATTN: Mr. C. Poslusny Mr. J. Knight, DE Mr. B. L. Grenier, NRR 8410220309 841019 I PDR ADOCK 05000499 A PDR

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Engineering Division Geotechnical and Ifaterial Branch Dr. Lyman Heller U.S. Nuclear Regulatory Comtission Ofi' ice of Nuclear Reactor Reguistion Mail Stop P-214 Washington, DC 20555 Dear Dr. Heller Please reference lateragency Agreement (IA) No. NRC-03-82-102; Work Crder No. Five (5), South Texas, Units 1 and 2. Attached as Enclosure 1 is a list of gootechnical related questions pertaining to the South Texas Project Final Safety Analysis Report (Volumes 1 through 16 and Responses to NRC Questions Volume 1 and 2). Responses to many of ,the questions nay be contained in the requested references shown on Enclocure 2. The Project and Financial Status report is at Euclosure

'3.

As a part of "this work order, we are required to prepare a draf t p Safety Evaluation Report (SER) and SSER. Please provide any standard formats, requirements, instructions, etc. for preparation of these documents. We would also like to'make a visit to the site at your 5

earliest convenience.

If you have any questions, please contact David E. Wright (FTS 129-2377, commercial 214-767-2377).

Sinceroly.

Arthur D. Denys, P.E.

Chief, Engineering Division Enclosures Copy furnished:

DAEN-ECE-G, ATTH: Mr. Dale Munger

, U.S. Nuclear Regulatory Comnission Contracting Officer, DC Director, Division of Engineering, ATTN: Mr. C. Posluany Mr. J. Knight, DE .

Mr. B. L. Grenior, URR N ,

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Questions STP - FSAR I.: Chapter 2, Section"2.4 - " Hydrologic Engineering" il.: Page 2.4-29. - For- the conservative failures postulated, the Cooling Reservoir embankment section is assumed to translate, intact, downstream for a distance of 200 feet. ' ' Once -flow begins through the breach, the embankment material will erode and ' soil, debris, etc. would be deposited against and adja-cent to the plant facilities. What effects, if any, would this material have on the operation or safety of the structures?

=2. Page 2.4-80 and 2.4-81. Potential problems (seepage, slides, overtopping,

-etc.) which could lead to an embankment-failure are generally slow developing thereby, allowing sufficient time for safe shutdown ors to take necessary remedial h action. ' Constant-surveillance throughout the operational life of the project L .should provide early warning of any potential problem. Nevertheless, the postu-

! Isted embankment failure was assumed to be instantaneous with a subsequent s' instantaneous flood wave against the plant structures. For such a remote occurrence, what' plans could or would be implemented to provide for safe L.. shutdown?

II. Chapter 2," Section 2.5.4 " Stability of Subsurface Materials"

1. Page 2.5.4-52, paragraph 2.5.4.5.5.2, subparagraph 2. The E layer was g ' compacted to a minimum dry unit weight of 98 lbs/f tJ. Based upon all labora-

: tory te.:ts cf the subgrade material, what range of percent relative density does

l. 98 lbs/ft3 correspond to?

l' i 2. Page 2.5.4-53, paragraph 2.5.4.5.5.2, Table 2.5.4-23, and Figure 2.5.4-57. What method or procedure was used to correlate in place density tests with-laboratory compaction data? For example, Table 2.5.4-23 indicates a mim-i mum dry density of 95.7 lb/ft3 was accomplished for the Unit 1 Turbine Gener-ator' Building (cohesive subgrade). From compaction curves for. Layer B'(figure l

L 2.5.4-57),;95.8 lb/ft3 would correspond to a loose 76.9 to 83.1' percent ~

! . compaction" depending upon which compaction test was most applicable.

~3. -Page 2.5.4-57, ASTM Standards. Since density control of structural fill

'or backfill was based on relative density, what is the purpose of " Moisture /

density relationship according to modified Proctor procedure (ASTM D 1557-70)."

14. ~ Page 2.5.4-105, paragraph 2.5.4.12.2. Since foundation verification was egenerally accomplished using rapid or standard test methods on the subgrade, what' conditions were encountered that led to the suspicion that the density was L not satisfactory at depth throughout the E layer?

l ;5. Page 2.5.4-106, paragraph 2.5.4.12.2. Information presented on Figure

. 2.5.B.5.3-5 indicates lenses or. seams of clay within layer E. What maximum

-_ thickness were these seams and did any of these affect the penetration rate of

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'the Vibroflot' probe such that prolonged jetting action may have created voids immediately beneath the clay seams? Such a condition could account for the introduction of such large amounts of new'soi1' material in the probe holes.

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Page 2.5.4-183, Table 2.5.4-23. (1)- Please distinguish, by Unified '

_ Soils Classification symbols,.between non-cuhesive and cohesive material. (2) f Required dry densities for -non-cohesive materials correspond to what per-E nu l. 'l s e- <- . , , - -, ,_ , , _. . . , _ . , . ., 7 , ,-r, r.. _ 3._ ,, .

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-l cent 1 relative density? (3) Please provide the results for Unit 1 Mech-Elec.

. Aux. Buf1 ding and the Unit 2 Reactor Containment and Fuel-Handling Buildings.

'7. Figures 2.5.4-54 and 2.5.4-54A. From a construction standpoint (speci-fications), what is the difference between Category I and Noncategory I struc-

.tural backfill?

, .8. ~ Figures 2.5.4-59 and 2.5.4-60. The actual gradation band plotted on

'these figures needs some clarification. Page 2.5.4-55 indicates gradation tests

'" prior to delivery of backfill to the project site" or at the site "before it was placed." Page 2.5.4-57 indicates classification tests were obtained from "the placed material" and page 2.5.4-60 indicates gradations on material

" delivered from the Parker Brothers plant." Which valves are actually plotted on the figures? 1

9. Figures 2.5.4-61 and 2.5.4-62. In conjunction with the data shown on these figures, pl. ease provide a brief discussion of the following:

(a) Was the structural backfill saturated during placement and com-paction?

(b) Were relative density max-min valves determined on material from a stockpile or on material af ter it has been placed and compacted?

(c) What approximate range or. band of maximum and minimum densities

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were obtained from all relative density tests?

(d) What procedure was used to correlate in place density tests with laboratory nax-min values?-

(e) Were any relative lensities less than 80 percent continuous over any. lift or zone or were these randomly oriented . vertically and horizontally?

10. Figure 2.5.4-93 (original " Ultimate Settlement by H-Space Analysis) and Figure 2.5.4-93 (Amendment 36). Ultimate settlement (1983 projections) based on construction data is generally 'about 0.5 inch ' greater than originally estimated. Please provide.a brief discussion for.the difference between the two results.

III. Chapter 2 - Section 2.5.5 " Stability of Slopes" i

1. Page 2.5.5-2, paragraph 2.5.5.2.1. This paragraph' indicates "no. weak soil strata are present in the surface soils." Page 2.5.6-11, paragraph 2.5.6.4.2.5 indicates, however, the ECP embankment material was placed at +3 percent to +8 percent of optimum moisture and compacted ~to a minimum 80 percent modified Proctor. Were any undisturbed samples and subsequent shear testing performed on materials that represented these conditions?

IV . ' ' Chapter 2 - Section 2.5.6 " Embankments and Dams"

1. Page 2.5.6-10, paragraph 2.5.6.4.1.5. What procedure was used to

correlate in place densities with laboratory compaction data or laboratory  !

max-min valves for relative density?

2. _Page 2.5.6-10, paragraph 2.5.6.4.1.6. Was the embankment over built to compensate.for the anticipat'ed 1 to 2 feet of settlement?

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• Page 2.5.6-12, paragraph 2.5.6.4.2.6.2 Was the computed 1 to 2 in.

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• ultimate settlement based on material compacted to a minimum 80 percent at +3 to r  ;+8 percent.of optimum. moisture?

, 4 .- Page 2.5.6-24~,' Table 2.5.6-2. Are strength valves for the embankment criginal design values or from record samples from the compacted embankment? If original valves, what percent compaction and moisture content was used? Also, in Table .2.5.6-4, what strengths we're used 'for: the post-construction analyses?

5 '. Figure 2.5.6-15; The " Interior Berm Detail" for Type '"A" Embankment

' indicates 45 or 55 feet width for-pore. pressures greater than 25 percent.whereas page '2.5.6-8 indicates. 35 feet was used. Please clarify. Also, are provisions,

' incorporated for future inspection and cleanout of the collector pipe beneath

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the dow_ stream bean?

Chapter 2 - Section 2.5. A " Foundation Verification" s

General Comment. In addition to the foundation verification field work

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performed, there are many references to a "geotechnical engineering evaluation" to determine.the adequacy of zones not verified. Briefly describe or present l

typical exampleu of what constituted a "geotechnical engineering evaluation."

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.2. Page '2.5. A-13, paragraph 2.5. A.7. Normalized data indicate 10 percent

- of the' foundation verification strength test results and 11 percent of the dry ~

idensities did not meet ~ minimum field acceptance criteria. What actual percen-

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tages .would these valves correspond to? _ Also, please provide a 'brief discussion

- of any, adverseL eonstruction conditions which may have prevented meeting the

, - minimum field acceptance criteria. The same comments also apply to paragraph' 2.5.A.8.

3. Tables 2.5.A.2-1 and 2.5.A.3-1. (1) Indicate by Unified Soils Classi-l fication symbols which materials' were considered cohesive and which were con-

'sidered cohesionless'. (2) Did-both the rapid method and standard method have

-~to meet-acceptance criteria? If not, which governed? (3) What range of

< percent compaction (cohesive material) and percent relative density (cohesion- ,

less material):do' the standard method test valves correspond to?

4. Table 2.5.A.5-1. 'This table indicates that much of the E layer required

. . some type of remedial action before verification. 'Please briefly describe the field or construction: conditions leading to these remedial actions.. Under the

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Remarks Column, what does the letter "M" represent (see page 2.5.A-31c, zones

'230 and 231)?

U ' Chapter 2 - Section 2.5.C "Geotechnical Monitoring"

[$( 1. ' General Comment'. Please provide a time plot of-settlement measured to -

74 0 date for,the Main Cooling Reservoir and Essential Cooling Pond embankments.

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, u, , , STP - FSAR-Request Copy of Following References j h .'E

= Reference No.' . Title e

s ;2.4.13-12' McClelland Engineers Inc., Geotechnical j Study Cooling Water Reservoir, South s

s Texas Project Supplements, Engineering

• k, Analyses and Recommendations, Embank-

, e ments, Dikes, and Borrow Areas, Volume t 3, October 31, 1975, and Addendum 1, February 25, 1976.

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- 2.5.4-63 '

Stanley D. Wilson, Consulting Engineer,

_ " Expert Comaittees Final Report on'the Adequacy of Category I Structural Backfill, South Texas Project," TPNS

'Y310KR1378 ASH, January 30, 1981.

. .2.5.5-13 A . letter report from Woodward-Clyde Consultants to Brown & Root Inc.,

dated August 1,1979 (Y570KR1378 AWC). . . <

2.5.6.7- McClelland Engineers, Inc.,'Geotechnical

- < Study, Cooling Water Reservoir, South Texas Project,. Volume 1, " Engineering i'

Analysis and Recommendations,

. Structurts," report to Brown & Root, 6: . Inc. (1975).

= 2.5.6-8. McClelland Engineers, Inc., Geotechnical

+ - ' Study, Cooling Water Reservoir, South Texas Project, report to Brown & Root,

. Inc. (1975).

2.5.6-13 Brown & Root Inc., Technical Reference-

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. Document, "ECP Earthwork Design and 1

Construction," TPNS 5Y570SQ005-1, January 31, 1980.

_ - 2.5.6-14 McClelland Engineers, Inc., Geotechnical Study, Cooling Water Reservoir, South Texas Project, "Underseepage Control,"

report to Brown & Root Inc., (1975).

.2.5.C-1 Brown & Root, Inc. Calculation No.

7Y310SC267-2B, " Subsidence Study",

i 8/6/31.

STP Construction Procedure A040KPCCP-14

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"Vibrofloatation".

. .-- QA Vibrofloatation Inspection Report, dated 5/3/76.

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"In'teragency Agreement ~ No. NRC-03-82-102; Work Order No. Five (5);

-South 1 Texas Project,- Units- 1 and 2; July 1984 to Sept. 30, 1984

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LI.. PROJECT STATUS

. 1.: Efforts completed: Received-16' Volumes of Final Safety Analysis =

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. Report, Volumes I.and LII of Responses to NRC Questions, and

= Amendments 1 through 40. Completed initial review of these

- documents and developed . list of questions.

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2.; No problems anticipated. ,

-3. Progress to date: Approximately 15. percent complete.

II. FINANCIAL STATUS

1. Total.COE-proposal - $36,850.

2. Funds expended to date . $5,212.66.

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