ML20134B252
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- UNITED STATES OF AMERICA 4-
~~
NUCLEAR REGULATORY COMMISSION,
3 6
BEFORE THE ATCMIC SAFETY AND LICENSING BOARD 7
3 1
9 10 f In the Matter of:
5 1
11 5
12
- EOUSTON LIGHTING & POWER 5
Docket Nos.
50-4980L 13,
5 50-4990L 14 -
5 L3,
(South Texas Project, 5
1g,
Units 1 & 2) 5 17 l 5
i
! LE l Is i 20 TESTIMONY ON B N OF ECUSTON LIGHTING & POWER CCMPANY, ET AL.
21 l 1
21 :
)
23 !
OF
' 24 !
23 5l MR. C. BERNT PETTERSSON
,fi MR. TIMOTHY K. LOGAN l
! 23 ;
'MR. CHARLES S. HEDGES 29 j MR. W. STEPHEN McKAY l 30 ON THE 32,
J 33 '
i 34 !
STRUCTURAL BACKFILL PROGRAM 32 '
AT STP
' 36 ;
, 37 ;
38 1 39 :
, 40
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$2 43 1
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if i 3'
~ 47 i 8508150562 850703 48
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) l LEIGHTOB4-293 PDR 4q, J
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- 4-L/zii i
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3 UNI 55D STATES OF AMERICA i
- - - 4.;.
. NUCLEAR. REGULATORY COMMISSICN 5,
6' 7i BEFORE Tm' ATOMIC SAFETY AND LICENSING BOARD 39l
~O In the Matter of:
5 3 ;
5
- o
. L2 '
1 ECUSTON LIGHTING & PCWER 5
Docket Nos.
50-4980L j
~
5 50-4990L 14 5
L3 (South Texas Project, 5
i 16 i Units 1 &,2) 5
.17 5
4
' LE !
19 1 20 !
TESTIMONY OF C. BERNT PETTERSSON, TIMOTHY K. LOGAN, CU R S S.
nj EEDGES and W.
STEPHEN McKAY ON THE STRUCTURAL BACKFILL PROGRAM
'y!
AT STP l
Q. 1 Please state your names.
23 '
A. 1 C. Bernt Pettersson, Timothy K. Logan, Charles S.
25 17!
Hedges, and.W. Stephen McKay.
- 23. !
29 i Q,. 2 Mr. Petterson, Mr. Hedges, Mr. McKay and Mr..
i 10 '
t 31 l Logan, by whom are you each employed?
32 '
} 33 f A. 2.
(CBF): I am employed by-Browrt & Root, Inc. (3&R)
-34 i (TKL): I am. employed by Houston Lighting & Power Company 33.
16 (g ),
37 i
38 '
(CSH): I am ergployed by Woodward-Clyde Consultants
- 19 !
' 10. l._...(WCc)., 4. consulting firm specializing in geotechnical en _.. _
41 !
12 i gineering.
13 i
'44.l (WSM): I am employed by Pittsburgh Testing Laboratorf is I gg -
(m), an independent -testing agent which performs earthworJc-47 l
- Lnspection and testing and other services at nuclear power 4g ;
39 i plants.
=0 i
/
. il l 2m 5
1
Q. 3 What is your position and what are your current
[
responsibilities?
A. 3 (CSP):
'I am Assistant Discipline Project Engineer I
(Civil Structural Discipline) for the South Texas Project (ST?).
Since 1974, 'I have been group leader for geotechnical f
engineerhg.
My responsibilities include development of B&R specificiations for selection of structural backfill materials, I
and for backfill placement, compaction, inspection and
?
L
'i testing.
I report directly to the Structural Discipline Project Engineer for STP.
(TKL): I am Project QA Supervisor for Rt.p 's W.A.
i Parish Unit #8 Project, a 650 MWe coal fired generating unit l
under construction at Thompsons, Texas.
I have primary t
l i
responsibility for the implementation of the QA program on
~
)
ll the project.
7
[
(CSE):
I am Project Manager for WCC's work at STP.
I I
have been Project Manager at STP for the past Sh years, and l l 1
for 2-k years prior to that I was periodically involved in I
I the site studies and preparation of the ST? PSAR documents.
l As Project Manager,for WCC, I supervise other task leaders
- l l'
. and staff engineers working at STP.
I also perfor:n engineer-1 Ll ing work related to STP geotechnical activities.
'I
)'
(WSM): I am the Corporata Manager for Quality Assurance l
(QA) at ETL.
I am responsible for the development and.
! l implementation of PTL's QA programs at several nucleitr i
t I
t r
. i l i, l
l I
l l
L 2
3 plants.
.I have worked for ST? since March 1976, when I 4, '
5 became PTL's Site Manager.
In July 1976, I left the STP 6.
7, site, but have remained involved with the Project by perform-S.
9' ing regular QA audits'of PTL activities at STP, selecting 10 PTL personnel for STP, and reviewing all of PTL's correspon-
., g U
dance between the site to the home office.
i 13 14 !
Q. 4 Please summarize your professional qualifications.
13
~
16 <
A. 4 (CBP): I have a degree in civil engineering from 1
17,
15 i the Technical Gymnasium in Norrkoping Sweden, and_ degrees is
~
19 \\
20 i geology with geotechnique and business administration from 2 ~' t g
[
Stockholm University.
I am a Registered Professional Engineer
-in Texas, and am. a member of the American Society of, Civil 23 I Engineers (ASCE), the Geological Society of America (GSA)
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t 47~ !
and the Swedish Geological Society.
Prior to joining B&R in i 2S I
~ - 29 ! ' " - I977,=I spent approximeteFf eleven years as.a geologist,. and.
'. 3 0 i as a civil and geotechnical engineer in the United States i
31 i 32 i and Sweden.
j 33 j
- '14 35 (TE) :
I have--a -Sachelor of Science degree from. the 6
36 j University of Houston (1972) and have taken post-baccalaureate I
37 38,}
courses at the same, university, specialiring in structural
,. 39,
- t 40' !
"and geotechnical engineering.
r am a registered Professional 41 l
, 42 j Engineer in Texas. and a past member of the Texas SocietI of
. 43 l
Professional Engineers and the American Society of Civil 44 45
. a. g i n e e r s..
46 47 l
48 j
49 l
30 l
51
19h7 From &466 until 1973 I was employed by EISP in rhe engineering departnent, where I'perfo'rmed civil / structural *
~
design work involving foundations and structures for trans-7, I'i mission, distribution, and substation facilities.
From 1973 until 1976 I was employed by Raymond Technical Facilities, Inc., an engineering consulting firm, as a designer and design engineer, performing civil and stfuctural design for l;
industrial facilities.
i I rejoined EIAF in June of 1976 as a Senior Engineer
'i in the QA department assigned to STP.
I was responsible for I,
l!.
including backfill placement and PTL activities.
In June, performing QA surveillance of all civil related activities, I I yt ll 1977 I was promoted to Lead Engineer.
In this capacity, I i i rj supervised the two to three EL&P personnel who performed QA Ii surveillance of all civil related activities at the.s.ite..
I I,
1i j
served in this capacity until June, 1978.
From January to E!
July, 1980, I returned to STP to serve on various task.
Ir forces and audit teams ~as. a technical advisor, EL&P QA 5!
I; representative, and Group Leader.
I!
5:
(CSE):
I have, a Bachelors degree and a Master of 7 i 3 i Science-degree in Civil Engineering from Georgia Institute of Technology, with specialiration in geotechnical engin'eer-
{
f j
ing.
I. am a. registered Professional Engineer in Illinois, l
I {
Georgia, Florida and Louisiana..
I am a member of the American 6
Society of civil Engineers (ASCE), the American. Society for 7
8 l
1 l
3 L
j i
ege
~ ~ - -
mu s s
L I
l 2
3 Testing and Materials (ASTM), the Louisiana Engineering 4
the American Council of Engineering Consultants the g
Society,.
6 7
Sigma XI Research Fraternity, and the American Nuclear 3
Society.
I am a past member of the ASCE Nuclear Structures g
10 '
Subcommittee for which I helped draft industry guidelines-11 L2 '
and standards relating to geotechnical engineering for 13 14 nuclear power plants.
v_o 16 I have twenty-four years of experience in geotechnical 97 l
{g engineering and civil construction, including sixteen years experience in the geotechnical engineering aspects of nuclear 20 2 '-
22l!
power plants.
This experience includes preparation of site
, 23 selection studies starting with Florida Power & Light's 24 ;
' 25 t Turkey Point Nuclear Power Plant, and preparation of licens--
26 l
- 23. j ing studies, geotechnical engineering designs and operating 7
29 procedures.
30 y
3gl (WSM): I have a Bachelors degree in civil engineering from the Carnegie Institate of Technology, and. an a Registered.
3.4 ;
Professional Engineer in Virginia and South Carolina..
I ait 35 36 ;
37 l a former member of the ASCE and a present member of the 38 American Concrete I,nstitute (ACI) and the American Society 39 '
for Quality control (ASQC).
I am a Certified Level III 40 j 41 '
Inspection Engineer under the American Society of'Nechanical
'~
42 43 '
44 l Engineering (ASME.) Code and under the American. National.
N!'
Shm4=% Institute- (-ANSI) criteria.
I an also.a;c # #ied.
16 47 lead auditor under ANSI standards.
48 49 50 i
.il
_3
r l
1 i
I have nineteen years of inspection and testing experi-
-[
enca including four years in PTL's soil mechanics department, r !
seven years as its District Manager in Roanoke, Virginia,
. l and eight years associated with PTL contracts for nuclear 0
[
power plant construction services.
l
' Q. 5 Mr. Hedges, please describe WCC's long-term Of relationship with STP.
0V l
A. 5 (CSE):
s :
^
WCC has been a subcontractor to B&R on STP since early 1973.
Following initial STP work relating l
@l l
g to geotechnical exploration techniques, WCC became involved
,'l in site exploration and geotechnical evaluation of.the STP
'f site.
This site related work by WCC led to the engineering, p
-i geology and seismology analyses and evaluations for plant Fj design and PSAR preparation.
After the STP Construction s
Permits were issued in 1975, WCC ccntinued its involvement as consultant to B&R during the construction phase of ST2 r
l and assistad. in the ESAR preparation.
WCC has worked with t
i bf the B&R geotechnical group in performing. studies, analyses 3!
f' and consultation.
At the same time, WCC regularly has made 3,
independent recommendations to B&R based on its own evalua-pr B
tions.
- q. 6 Panel, what is the purpose of your testimonyY ~
~
3 A.
6 (Panes.) :
The purpose of our testimony is to
~
describe the respective activities performed. by MAP, B&R, PTL and WCC in developing and implemenH ng the Category I
. I l
8 4
a_
e h e.
1 2
3 structural backfill program at STP, the Task Force review and 5
i 5
other special evaluations conducted in response to the NRC Show 6'
7i cause order, and the results of all the show cause activities.
S 9
Q. 7 Please describe briefly how backfill is placed at 90 h,
STP.
A. 7 (Panel):
The backfill is placed, compacted, and 14 '
accepted in individual layers or lifts.
The backfill placed 19,
l 15 at one tima in a specific area is called a placement and 1
17,
lg !
several placements of backfill are generally required to 143 complete one lift over an entire building foundation area.
21,
Depending upon the work space requirements for other construc-32
- 23 tion activities, a liit over an entire building area may not 24 25 he completed before an overlying lift is started.
In.any 26 7!
event, all placements are compacted before an overlying 21 !
29 !
placement is.made.
30 '
31 l Q. 8 Mr. Pettersson, Mr. Hedges and Mr. Logan, please 32 '
33-describe the development of the requirements and specifica-34 i 35 l n
at g vern ma er a se e n, p a ement and compac-36 j 37 :
tion of backfill at STP.
33 '
A. 8 (CBP, CSE and TKL): No specific code or standard 39 I
40 i governs placement and compaction of Category I structural 41 i 42 backfill for the safety-related structures at STP.
The 43,
44, j physical properties of the backfill must be consistent with 45 I
.6'!
' ' the structural design-criteria for foundations and embedded.
walls f all Category I structures.
49 :
- O j s1. I
f, e
s requires rhat soils supporting nuclear power plant foundations m'ust be able to w'ithstand certain types of loads without
~
~
p excessive settlement; i.e.,
the backfill must have sufficient 9..
pf density to provide an' adequate safety factor against liquefac-ff tion.
I!
To satisfy these general provisions, specification 3,
4 requirements were developed jointly by B&R and WCC based in 5,i 5I large part on WCC's selection of backfill material and its 7I Ll testing, evaluation and analysis of the backfill material g':,
3;{
ultimately used at STP.
EL&P then reviewed and approved all
~
specifications prior to their implementation.
The.specifica-3-f tient nave not varied significantly since the beginning of 4,;
5:j the Project.
5!
7 L WCC, in cooper.
.an with S&R,. conducted a regional
!!}l investigation of possible structural' backfill material 3: !
L:
sources in 1974.
The Eagle Lake Area (Colorado River alluvium),
g!
i g;
approximately 55 miles from. the STP site, was determined to
$. i be the best source area based on the type and volume of i
5 ~. j Ol material available.
F!
l!
Based on laboratory testing of this material, WCC F
3l recommended._that an 80%. relative density requirement for ti backfill at STP would provide an ample factor of safety I lL g
agas.nst liquefaction.
This. requirement was. based on the STP i
- g..
design. basis Safe Shutdown Earthquake (SSE') cri?M-a., and r
l P
I l
3
c.
L 2
3 was considered conservative in view of geotechnical engineer-4' 5!
~~
ing practice'and the low seismicity at ST?.
This 80% require-i 6'
7l ment was incorporated into 5 2.5.4 of the PsAa, and is the 8'
g only commitment regarding granular backfill compaction in the construction permit licensing documents.
~
12 i WCC performed additional analyses and recommended, 13 14 consistent with the PSAR, that backfill compacted to a
- 13
'- 16 :
mimmum relative density of 75% and an average relative 17 '
l ig l density of 80% would provide a more than adequate safety 99 \\
20 factor against liquefaction.
To be conservative, B&R adopted a specification requirement for STP providing for a minimum 23 i relative density of 80% and an average relative density of
- 24 i 25 84%.
WCC also recommended gradation limits for the backfill 25
'7 7
material to be used at STP, and these gradation criteria 4E j 23 l were incorporated by B&R into the specification.
EL&?
30 !
_ 31 p reviewed and approved the material, gradation and density 32 :
73 requirements. of the specific 7. tion.
34 Based on WCC recommendations, B&R Engineering then 25 !
76 '
developed a construction specification requiring that uncon-37 38.
pacted backfill lifts be limited to an 18 inch maximum 39 !
40 thickness.
Under the specification, uncompacted lifts of 24 41 l
~
i 42 !
inches are permitted to be used at the option of Construction 43 p,
if the adequacy of the backfill compactiert is demonstrated 4Si 46' !
by a documented. test fill (field test) program.
.7 l 48 i 49 l 50 ;
.1. i i
1.
.g.
?
L l
Based on additional recommendations by WCC, a specifi-
)
i ;
cation was developed requiring at least one field density iir!
test for every 20,000 square feet of unrestricted backfill
'f lift.
The specification criterion was based on the uniform I
gradation of the STP backfill, the planned placement and compaction operations and the volume of material contained in each density test area.
This testing provides data j
demonstrating the relative density of the total volume of 1i'l Category I compacted structural backfill.
1 i
(!
For every fourth field density test, at least one
!!'l laboratory maximum-minimum test and one gradation test is to i
be performed.
The decision to require one test in four was
//
based on the degree of uniformity of the STP backfill, and i
(
t lt war considered conservative by industry standards.
The purpose of the maximum-minimum laboratory test is to deter-l mine a material's maximum density when well compacted, and l !
l its minimum density when uncompacted in its most loose
!Iil state.
The actual in-place relative density value is deter-i mined by a mathematical formula utilizing the laboratory
.i determined maximum,and minimum density values and the in-place j
density value determined by the field density tests.
The i
l actual relative density value is then compared to the 80% -
iI!
acceptance criteria.
The purpose of the gradation test is to determine the particle size distribution in backfill material.
The results of this test must meet applicable i
specification requirements.
l 3
l L
2 3
Q. 9 Mr. Pettersrson and Mr. Hedges, please describe the development of the construction procedures governing 6
7i backfill at STP.
3' A.
9 (CEP, CSE):
Construction procedures were de-g 70gl veloped in 1976 based on the STP specification requirements 12 and on standard industry practice.
It has always been
~
13 14 understood by Construction that these are "end product" l 1S,
15 i procedures requiring backfill to be compacted until the 17 I ig !
proper density is achieved.
It is the result of testing 13 ;
20 l that we rely upon to assure adequate density has been achieved, 2' '
i not the number of passes of the compaction equipment.
22 23 l Except for minor editorial variations, the procedures origi-24 j.
25 !
nally developed were the same as those in effect at the time 25 1 7l 43 i of the NRC Order to Show Cause.
i 29 l A
10-ton steel drum vibratory roller was selected to i 30 i l
31 l ensure effective compaction of 18-inch lifts.
The decision 32 l was made to limit the lifts.to 18 inches., thereby rejecting
- 33 34 !
the option of using 24-inch lifts.
.35 i 36 l Although the specification does not require use of a 37 38 !
formal test fill pr,ogram to verify the acceptability of 39 i 40 i
- compaction of 18-inch lifts-prior to placement in Category I
~
41 l 42 1 areas, construction decided to conduct an informal, voluntary 43 '
g; test fill program to confirm the adequacf of the compaction 4 5 :l methodss This: tes.t fill program: was conducted: in.197'6 by-
,g
, I-
'I placing several lifts and compacting them with the roller 43 !
49 i 80 !
1I
-u-
S 2
8I planned to be used in actual construction of the fill.
The
)
45' ' - ~ number o-f roller passes-on each lift was varied on different 6 I7l portions of the lift.
Density tests were then taken at 3i l
9; several depths to determine the density achieved by the Of different compaction effortsf.
1, 1!
3&R's -Site Geotechnical Engineering representative 1) 6i evaluated the results of this program and conservatively 5
g recommended that a minimum of 12 roller passes be incorpo-F' y
rated into the construction procedures.
construction, in 15 developing the construction procedures, concluded that a g
minimum of 12 passes would be necessary only on the surface 13 lift, which. would not receive further densification.by 6;
5' compaction of overlying lifts, and that a minimum of 8 l9 7
passes would be acceptable for the lower lifts.
of course, J
g p
if the 8 or 12 passes did not compact the structural backfill
@i gl to the required density,. additional passes were required f.
until a minimum of 80%. relative density and an 84% average I.
relative density had been achieved.
9!
After 8 or 12 passes, it would be appropriate to begin
^
T!
@l in-place density test-hg to evaluate the adequacy of compac-
@l g
tion.
The first twenty field density tests made in unre--
b stricted category I areas verified the adequacy of the 8g relative density achieved by this procedure.
b Q. 10 Mr. Pettersson, Mr. Logan and Mr. McKay, please-
@7 describe how the backfill program at ST? was monitored to e1 l
l l
I
i l.
2 3
assure compliance with applicable specifications and proce-
)
1 dures..
s 6'
7t A. 10 (CSP, TKL, WSM): An Earthwork Inspection and 3*
g Testing Specification was developed and was to be imple-10Q' mented by PTL.
This specification das developed to provide 2
general criteria for quality control of th'e backfill. place-ment and compaction activities, and has not been signifi-16 ;
cantly modified since it was first developed.
Specifically,
( 17 i LE l PTL Inspectors are to provide continuous inspection of the 19 i 20 l placement of all backfill material, which means that the
,n
!]l Inspectors are required to be present in the general work area where backfill is being placed or compacted, and are D
required to observe the type of material used, lift thick-25 i
7!
nesses and operation,of compaction equipment to ensure d!
29 l compliance with applicable specifications and procedures.
' 10 i J2,,
With B&R review and approval, PTL developed procedures 32 !
i 13 ;
to implement the specification requirements relating-to 34 '
35 i inspection and tesH ng of the backfill.
In addition, PTL 16 j developed several procedures relating to all 18 criteria of 17 38 ;'
10 C.F.R. Part 50,. Appendix B and other specified codes.
19 10 i These procedures include provisions for personnel certifica-4t r
12 -
tion, equipment control and documentation.
\\3 l 4.$ l First, as backfill material was placed in excavated is. i ig l areas., PTL QC Inspectors determined the actual lift thickness 1:
to assure that it did not exceed 18 inches.
If deviations
,$8 !
19 !
30l
.l 1
I 9
were observed, B&R Construction personnel corrected then before. compaction began,.-and. the PTL Inspectors reviewed the.
o..
work for final compliance.
The Inspectors then recorded their observations on checklists and on Earthwork Inspection i
Reports (EIR's).
The latter provide a narrative description i
of the entire placement and compaction process.
In completing these checklists, the PTL Inspectors generally marked that 4
the lift thickness was 18 inches, indicating thy it was 18 hI inches or less and that it satisfied the applicable B&R
)!
)
specifications.
This procedure subsequently was amended as r !
a result of the NRC Inspection Report 79-19, which. is dis-I!
cussed later in this testimony.
L!
il Compaction generally was performed for several hours i i Ii depending on the sire of the rolled areas.
Before this i!
s
) !
process was. started, PTL QC Inspectors checked the equipment 3!
Lj to be used, and before the process was completed, the Inspectors tI gl checked to be sure that the minimum required number of 6i 5i
.11er passes had been hade and that the compaction process Ii was uniform.
Again, a11 observations were recorded on r
Ii checklists and in the EIR's, and deviations were corrected F:
I and reviewed before the next backfill placement could begin.
i PTL Inspectors remained in the area where compaction-I g
was taking place until the process was completed.
- However, i
g because the B&R procedure requires only a minimum. number of i
roller passes, the Inspectors only observed the actual 1
Fl I
. i.
_a_
l l
l
L 2
3 performance of the roller passes long enough to assure 4
~5' themse1Ves that this' minimum numberhad'been achieved..
~
~
6 7
After that time, consistent with their understanding of the 3'
g continuous inspection requirement, they generally observed iGg the compaction efforts but,did not necessarily observe each
~
and every pass.
When compaction was completed and they were 14 satisfied, they indicated on the checklist that the compac-t LG
~
16 ;
tion effort was " acceptable" under the applicable construc-
-17 i j Ig l tion procedure.
This procedure was amended as a result of 19 ;
20 NRC Inspection Report 79-19.
' 22, j To determine the density of each lift after compaction, 22 U
PTL Inspectors generally performed at least one field density i
2 4 !.
25 :
test in accordance with the specification requirements.
. 26 ;
'7 i Although there originally was no specified test depth, the
/.S i
, 29-i Inspectors generally tested at the top of the immediately 30 !
underlying lift.
If the tests revealed a relative density 21 ;
of less than 80% or less. than an 84%.' average, 32 :
additional 33 h
rolling had to be performed until acceptable test results 36 '
37 !
were achieved.
As a result of NRC Inspection Report 79-19, 38 !
B&R amended its specification to provide for specified test 39 40 i depths, and PTL amended its procedures accordingly.
41 l 42 :
Inspectors indicated on the checklist, in the EIR, and
~
43 44 in separate Density Test Reports whether the test confirmed 45 1 46 i that the-compaction had been successful; i.e., whether the-l required relative density had been achieved.
They also 49 l CO 11 j
t i
- 1.
obtained backfill field samples for the laboratory tests.
~
To verify that' the backfill met ~ the' 80% relative density requirement, PTL QC Inspectors established field acceptance criteria by averaging twenty maximum-minimum laboratory tests.
The twenty-test sample, which was based on considera-tion of the gradation uniformity of the STP backfill material, provided a sufficient. data base from which to derive represen-tative field acceptance criteria.
The results of the laboratory tests were recorded
, - in separate Laboratory Test Reports.
Although it was not required, the Inspectors generally kept informal, Field Density Test Log Books which list all the tests by number
- .- ancL inM e ate which. -test locations have been. used..to obtain samples for laboratory testing l
l Completed EIR's, checklists, Densit'I Test Reports and
'i Laboratory-Test Reports were provided to-the PTL STP. Site Manager for his review.
They were then transmitted to the i
B&R QA/QC Supervisor in' charge of PTL activities for his f
review and signature.
Finally, these reports were transmitted' l :
to B&R Construction,and Engineering Supervisors. for their i
information and to the STP QA vault for filing as Project QA l
records.
i i
Since August 1976, the B&R QA/QC Supervisor has been l
located. in the PTL facilities. at the STP' site where he has had daily contact with the PTL site manager and other PTL l
personnel.
Accordingly, B&R QA/qc has additionally monitored I
i
! l.
- J. 6 --
3, 2
3 PTL activities and has i= proved the QA program implementation 4
-5u through daily discussions with PTL personnel at the site.
6, 7,
In addition to this daily monitoring activity, B&R QA 8
9; personnel have performed regular surveillance of PTL's
]O 9
inspection and testing activities, and B&R's Audit Group has 12 performed audits of the STP backfill program at least annually.
13,
, 14 PTL also has an internal audit program, and has audited its 15
' 16 -
own activities at least annually.
The results of these 17.
,I 15 '
audits have been transmitted to B&R.
i 19 i
~
20 ;
Q. 11 Mr. Logan, please describe the surveillance i 31 !
i t.9, performed by BL&P QA on the Category I structural backfill-23
[ I4 ;
program at STP?
- l. 23 l A. 11 (TKL):
Backfill material qualification, placement,
~ 26 j 17 I inspection and testing were monitored by HL&P QA personnel 3i 29 ;
through the use of prepared. surveillance checklists.
The
)
30 !
' 31 i checklists consisted of specific questions regarding require-4 31 !
. y ;,
ments from the B&R specifications and B&R and PTL procedures.
l There were two checkIists which covered all the major aspects
,36 described above..
Cne of these checklists dealt with field i
i 37 l 38 !
activities; i.e., m.aterial placement, compaction, inspection, 29 l
' 40 l and in-place density testing.
The other QA checklist covered 41 l
, 42,
laboratory analysis; i.e.,
material qualification testing,
~
13 '
44 compaction testing, and. B&R QA surveillance of PTL.
Another 45 checklist that also affected.the-backfill area covered.
. gg 7~
48 j calibratien of laboratory equipment as a part of all measuring 49 l 90 i
-9 I,
j 1 l
.,,.,,,.,n,-v,--,. -,,. - -- -,, - - - - -, - - - -, - -, - - - - - -
i gn__a.~L fbf M.. t:4 V
and test equipment., Surveillance using the checklists was
~' performed a minimum of"once~ per' month.
~
~ Between March 1976 and September 1980, EL&P utilired the checklists to perform surveillance on the PTL laboratory 57 times.
Between May 1976 and September 1980, surveillance of field activities utilizing the checklists was performed 53 times.
In addition to the formal, documented surveillance l
described above, EL&P QA personnel performed random daily informal monitoring of project activities.
Findings from.
the informal monitoring activities were generally transmitted orally to the proper B&R or PTL personnel.
Any resulting
. documentation was generated by the affected organization.
Q. 12 Mr. Pettersson and Mr. Hedges, were backfill i
l placement and compaction methods other than those described 1
l
. __in. the previous aniswer ever used?_ U so, explain these__
i l,
methods..
A. 12 (CBP, CSH)i In areas close to plant structures i
- or otherwise too confined to permit use of the-vibratory 1
rollers,. backfill was placed using hand operated compaction cquipment.
Specific procedures describe how the placements
- chould be made-ande tested in-these restricted -areas.
'~
In isolated areas, methods other than the ones pre-i l
vicusly described were used to densify the structural backfill i
- or to provide adequate foundation support.
The methods _ _ _ _ _ _ -
'L
.2 3
employed were.vibroflotation, _sratic rolling and grouting --
'5
all three of which 'are' comhon construction industry' practices.
'~
6 7,
vibroflotation is a field procedure identified in the 9
Structural Backfill specification which may be used when i
approved by Engineering.
The vibroflotation procedure 12 employs mechanical vibration and simultaneous water-jetting 13,
14 ta. densify a_ soil. mass.
This process was used. to: densify. _...
15 !
16 !
Category I backfill loosely placed in an exploratory trench
~
17 i Ig ;
approximately 10 feet deep which was dug to evaluate the 9a i Q;
extent of suspected contaminated backfill; i.e., backfill -
containing soil types different from the granular material.
23 l ITse of 18-inch lifts compacted by a vibratory roller was not 24 :
- 25. !
-feasible-in-this instance because o-f the depthe small area -
26 !
~
and moisture conditions in and around the trench.
Following 2h j 29 i the vibroflotation treatment, ten borings including Standard 30 ;
'1i
-Penetration Tests (SPT) were-made.
The-results-of the tests-3 32 33 verified that a: satisfactory densitf had been achieved for 34 the vibrofloated hackfill material.
35 i
~
36 :
Static Rolling' refers to the use of the 10-ton vibratorf-37 I 38 !
roller with the vibrator shut off.
The first lift placed 39 i
- 41 l 40 over natural subgrade was statically rolled when necessarf i
42 j to prevent subgrade pumping, and the first lift placed over 43 '
44 concrete mudseals.was. statically rolled when necessary to 1
45 prevent damage to those-items.
In.some cases, static rolling 4g,
l 4.
was employed along with water saturation to densify the 48 49 final backfill surface more thoroughly.
i 00 :
l I
-u-l
L 1
s i
To verify that the reported statically rolled lifts rece'ived' adequate comp ction', WCC conducted ~an~ evaluation of r
the incidents of static rolling, and confirmed that the
)i
)
vibratory rolling of succeeding lifts had taken place until the statically rolled lift satisfied the density requirements.
I Grouting refers to placement of a cement-sand-water shrink mix into small voids which are otherwise inaccessible
[
for backfill placement and compaction.
This method was used i
rit STP to fill surface voids which had developed under the edges of previously poured concrete slabs due to erosion from rainwater runoff.
"'he grout in these small areas is j
inherently stronger than the backfill it has replaced and is therefore considered to be acceptable.
(
i As discussed below and in the testimony of Mr. Stanley D.
]
Wilson and Mr. Thomas Kirkland, these bac.Kfill placement h
methods were reviewed in response to the NRC Show Cause i((
Order by an EL&P/B&R Task. Force and an independent F.xpert t
Committee.
The Expert committee composed of Mr. Wilson and l
Drs. H. Bolton Seed. and A. J. Hendron reviewed the use of
'l Bl these methods and f,ound them to be appropriate in all Di 3'
instances.
L g
Q. 13 Mr. McKay and Mr. Logan, were there problems' -
1 I
- 6. I identified by Project personnel regarding QA activities:
prior to the NRC's Order to Show Cause?
If so, what were-I those problems and how were they resolved?
EFj s
L
I 1,
l
- 2:
l A. 13 (WSM, TKL): Both B&R Audit Group personnel and
' BL&P QA"per'sonnel identified procedural and h'ardware problems
~
H 6'
1 y
regarding the QA program.
For example, a stop Work order 9
was issued in 1976 when B&R's QA auditors discovered that h
PTL had not correctly calibrated their sand cones used for
~
12 i in-place density tests.
Consequently, several density tests 13 !
14 '
previously accepted by PTL were found not to meet tha accep-L5
~
16 l tance criteria established when the sand cones were recali-17 ig i brated, and the tests were dispositioned as nonconformances.
ta{
After B&R reviewed-the situation and found the. tests"to be gf 2T acceptable, the nonconformances were closed out.
To prevent 23 a recurrence of such problems, PTL increased the frequency 24 25
- of its.. internal audits and provided additional. home offica 26 i 2a i support to'STP.
29 !
In.1976, pursuant to a different. B&R audit of PTL 30 1 31, l
-activities,- the B&R-QA Department found several procedural 32 !
discrepancies in. PTL's inspection and testing program.
33 Equipment was identified incorrectly, forms were not completed 16 and. equipment was not always calibrated with sufficient 37
~
38 frequency.
As a re,sult of these problems, PTL clarified its 39 !
40 j procedures for ease of underst=_nd4 ng, improved its overall 41 4
~
42 i management control, increased its on-site technical support, 43 '
.g j and. implemented a. trai ning program.
In addition, tha B&R 45 !
4 l
QA/QC Department. become more closel'f involved in the daily
+!
~ management and surveillance of PTL's on-site work.
i 48 !
i 49 '
en i
\\
\\
l
-2 2.-
l L
EL&P surveillance also discovered a few problems with
~
( e.
respect to the B&R QA and PTL activities.
The problems, ff which had no effect on the quality of the backfill, generally concerned minor errors in completing, reviewing and filing forms.
These discrepancies all were corrected.
{
Q. 14 Mr. Logan and Mr. McKay, what did the NRC audits reveal about the STP backfill program prior to late 19797
~
l A. 14 (TKL, WSM) The NRC audited the backf.'.ll program I[j at STP several times between 1976 and late 1979.
Generally, if these audits found the activities at STP to be in compliance i
((
with specifications and procedures concerning placement and compaction of backfill.
For example, in Inspection Report i!
76-07 dated December 21, 1976, the NRC reviewed the STP i!
sieve analyses, the relationship between laboratory and
~
l!
>l field *.esting, and backfill placement and compaction ac*dvi-l,I ties..The backfill quality and construction activities were r 1
[j found to meet applicable specifications and procedures.
In i
f
-Inspection Report 77 dated May 16, 1977, the NRC found (j
that the STP in-place density tests were in compliance with I!.
applicable specific,ations.
In Inspection Report 78-10 dated l'(
June 20, 1978, the in-place density tests, laboratory maximum-
[j minimum tests and gradation tests were found satisfactory.
\\!
1 In. addition, B&R QA surveillance of BTL activu.!es was found p
I to comply with applicable procedures.
In Inspection Report g
l 79-18 dated January 16, 1980, the NRC found backfill compac-I I
l P
l tion and in-place density testing to be satisfactory.
{
L
-22.-
?
n, 2
'I Inspection Report 77-06 dated May 16, 1977 did note
- 4. p
~.
5i noncompliances regarding the QA program in that B&R surveil-6' 7 !
lance of PTL activities was not conducted frequently 8
-l9{
enough, improper peersonnel were reviewing the surveillance 10
,gl reports, and those reports were not filed and retained
~ IU[
as required.
These noncompliances were resolved and closed L3 I, 1 4 '
out in the subsequent NRC Inspection Report 77-09, dated 1.5 l 16 t October 12, 1977.
? 17 Ig !
Q. 15 Panel, what actions were taken as a result of 13 i 20 f findings regarding the STP backfill program contained in the n,gf NRC Inspection Report 79-19 dated April 28, 19807 t 23 {
A. 15 (Panel):
The NRC reported six items of noncom- -
I 24 25 pliance regarding the STP backfill program in Inspection 26:l T!
Report 79-19: (1) PTL's procedures did not provide instruc-
' 28 l 29 1
- tions for depth. of in-place density testing; (2) B&R construc-g 30 l 1* 31, l
, tion procedures failed to set forth an identified and docu-
' 32. !
33 i mented basis for the acceptability of the required minimum
\\
--' 34 l ^ - of 8 roller passes for embedded lifts; (3) PTL did-not -
42-35
' 36 !
record the actual number of roller passes or the actual lift
- 37
, 38 !
thicknesses in the,EIR's; (4) the PTL relative density test 39 i l
I 40 '
apparatus was broken for a period between November 1979 and
-- 1 41 l 43 42 January 1980, and backfill placement proceeded although the required 5.aboratory tests could not be performed; (5) WCC 44
' 45 used. a nonconforming-hammer for Standard Penetration Tests 5,
,48lI
'7 of the backfill from January 28, 1980 to Februarf 4,
- 1980,
. 49 '
"O 1I i
i..
--v,y
--,----.m_4w5
L 2
s 3;
and (6) WCC used a nonconforming split spoon for its Standard 4)
~
5)
Penetration Testing'. ' All of these ' items have been sa'tisfac'-
6I 7[
t rily closed out by the NRC in Investigation Reports 80-17 8'
and 80-19, dated July 16, 1980 and August 8, 1980, respectively.
1 9j
(
First', B&R, with EL&P, review and approval, amended its L2 i backfill. specification to provide criteria 'or the density L3,
L4 '
testing depth of embedded and surface lifts.
Out of every L5 V L6 l ten tests, six tests must be taken near the top of the L7 L gl underlying lift, two tests near the center of tw underlying LS i lift and two tests near the bottom of the surface lift.
gg 21 Tests near the bottom of surface lifts must always be ac-22 22 companied by tests in the underlying lift to ensure that all 24 l 25 !
lifts are actually tested.
Density tests of surface lifts 26 !
7j located immediately below foundations must be taken at a
$3 depth of six to twelve inches.
PTL subsequently amended its
% :j procedures to conform to the revised specification.
a t
Second, the NRC examined the results of the 1976 and q
Ok 1980 test fill programs and concluded that B&R did in fact 35 Of have an adequate basis for its procedural requirement that a BT
@8 minimum of eight roller passes be made for 18-inch embedded 1
89 i
'40-l lifts.
The densiry test-results obtained from these programs bl verified that the incremental gain in density rapidly Emin-62 03 ishes for each. roller pass beyond eight and that the overall g
OI density in an embedded lift is. greatly increased after 8 l0 G,
lO7 passes on the overlying lift.
Therefore, B&R's procedure 48 l69 So
'51 l'
_u l
[
l
~
1 1
3 requiring at least eight passes before beginning in-place i
1
.. 4, 5-density 't'esting. was found to be' appropriate.
~
^
6' 7i Third, B&R, with HL&P review and approval, amended its 39[
Earthwork Construction Specification in June 1980 to require
{'O' that the PTL Inspectors. determine and record the actual number of roller passes and the actual uncompacted lift
~
14 thicknesses.
The number of roller passes must be determined 13 ;
' 16 l either by actually counting the passes or by inspection to 17 i ig l ensure adherence to a specific roller pattern defined in the
'9, 20,
newly amended backfill specification and in construction 21 !
i pr cedures.
21 23[
Fourth, PTL replaced its defective equipment used for 24,
25 maximum density determination and obtained back-up equipment.
26 l 27' !
The untested backfill samples which had been collected 23 !
29 !
during the period when the equipment'was not functioning 30' !
31 l were subsequently tested and accepted.
32 I Finally, the two nonconforming pieces of equipment used 33 34-l in several of WCC's Standard Penetration Tests were repl. aced 35
- 36 '
with conforming equipment.
The WCC test procedures were 37 38 '
modified to include dimension and weight tolerances.
WCC 39 !
40 i also evaluated the tests performed with those nonconforming 41 !
~~
42 !
items and found that the test results were not significantly 43 !
44 '
affected by the nonconformances.
45 l As. a; result of NRC's. description of these findings. at.
4g 47 !
the exit interview on January 26, 1980, B&R and EL&P asked 48 i i
49 '
SO i 51 l i
! l y----
---w.---y,-%.w,. -
e
,,w,,,
py
____y_
y,_
,y
___,,o.,
nm,---.y m--
L
- 2 3,
WCC in Januarf 1980 to begin a soil test. boring progran to
/
4,.
.. evaluate"the'overail backfill quality at STP.
The results
~
5 6i 7
of this program indicated that all of the backfill in the
'I Unit 1 area had relative densities equal to or greater than I
9 i 0l 80%, but that there were four small areas in the vicinity of L2 ;
Unit 2 with a relative density less than 80%.
Further tests
[3 l L4 ;
of the four questionable areas were made. by B&R and WCC with L5 !
LS j the assistance of Dr. E. B. Seed, a noted authority on the L7 '
behavior of soils.
These tests indicated that the backfill gg O!
in the four areas was sufficiently dense to provide a sub-to &
$1 !
stantial degree of safety against liquefaction, and that no 12,
13[
further testing or remedial work was necessarf.
Z4 l 15j Q. 16 Mr. Pettersson, as a result of Inspection Report Z6 a s
17 ".
79-19, were any additional changes made to B&R's surveillance j
13 i gg j progrant regarding STP backfill?
30'l A. 16 (CEP):
Yes.
Effective June 20, 1980, B&R 3,. 1 Ul Resident Engineering personnel are required co review on a 13 -
34 daily basis PTL's inspection and testing activities and to is 36 (
review PTL's documentation prior to issuance.
These personnel 37 33 also are required to note all observations in reports and 19 i 40 document any deficiencies and subsequent corrective actions.
41 i 42 !
Q. 17 Mr. Pettersson, Mr. Logan and Mr. Hedges, please I
describe the actions taken with respect.to the STP backfill 43 !
program in response to the Show Cause ordsr.
46 I 67 !
48 I 49 '.
50 l
EL l
=
- e. o -
j "s
1 2
3 A. 17 (CEP, TU., CSE):
Immediately after the NRC 4
"5L issued"its o der td'show' Cause, a join 'S&R/EI.&P ' Task Force
~
6-7i was set up to respond to the specific items in the order S
9 !
regarding the backfill program.
This Task Force subsequently 10 '
g spent approximately seven months reviewing thousands of 2
~
quality control documents to verify the overall adequacy of L3
, 14 the backfill material and the backfill placement, compaction, iJt
! 1 6 i, testing and inspection.
In addition to the Task Force, an
,17 i
!.g '
independent Expert committee of acknowledged leaders within 69 \\
20 ;
the geotechnical profession was retained to review the I (1 !
ig j backfill placement and compaction program at ST? and to I
determine the overall engineering adequacy of the in-place
'di backfill.
Finally, WCC performed additional special studies 25 !
~ 7~ !
necessary for the show cause effort, including a co pm rehen-
.S 4 29 l sive-statistical analysis of the category I structural
.' 10 :
' J2, -
backfill field density results.
32.!
ii,,
The following activities were conducted with respect to f
category I structural backfill placement in response to the
.r,6 :
Show cause order:
i7 l-38 (1)
A test f411 program was established to confirm the
'79 i
- 0
. adequacy of the construction methods used during the category i 41
- 2 '
structural backfill placements;
.3i sg t (2)
The. backfill material tested for the design studies
^; '5g, was compared to the material actually placed for-the Category I 7 '!
structures; 48 !
19 !
60l L
- i..
,,-n-, - -
---,--,----py er---
w
,-----w-
---ey g
---me
1 l
~ '
f L
1' 3-(3) cross-sectional drawings were developed to show 4.I
' 'the sequence of backfill' placemen'ts and liff tiiicknesses and 5
6; 7;
to show the locations of the in-plat.e density tests and S
9 results; (4)
EIR's were reviewed to detemine whether the reported 2 ',
work demonstrated compliance with the backfill specifications
.3 A'
and the construction procedures;
.6 '
(5)
The field density tests were analyzed to determine
.7.'
,g !
the density distribution and the representativeness of the 9!
EQ L tests; f
(6)
The relative density requirements of the. backfill L3!
were evaluated to determine the effect of localized areas
[4 !
L5 !
with relative densities of less than 80%;
LG \\
L7 '
(7)
The density distributions within the surface lift LS t
[3l immediately below structural foundations were analyzed; EG I g1 -
(8)
WCC's previgusly-performed boring programs were
[2 !
reexamined to obtain additional data on the engineering g
I4f adequacy of the backfill;
~
15 ;
16 !
(9)
The maximum / minimum 5.aboratory density test results 17 l L8 i were verified by a,different laboratory from the on-site QC
~
[9 64 i soils Laboratory; and b1 i 62 ;
(10)
Data concerning generic or specific problems with 42 '
the backfill construction and QC procedures was evaluated, g ;
63 and corrective actions were developed as required.
66 1
67 68 69 E0 l
El I
i. _.. _.....
s.
'l 2
3 I Q. 18 What were the results of the Show Cause verifica-4'
~
^
0 tion activities?
6' 7
A.
18 (CSP, TKL and CSE) The results of these Show f.
Cause verification activities demonstrate that the str'actural 9
10 backfill at STP has a relative density which exceeds the 11 12 :
design requirements, that the. frequency of backfill testing
~
13 '
14 has exceeded the specification requirement, and-that the IS
- 16 '
construction procedures utilired have been adequate to 17 i 1g '
ensure that the quality of the in-place backfill satisfies 13 i ja applicable specifications.
2t 22 ;-
In-place Category I structural backfill material at STP 23 L was confirmed to be from the same geologic formation and to 24 i 25 ;
have the same gradation. and particle shape as the material 26 ;
tested for the ST? design studies.
Minor changes which have J.S r i
29.;
occurred during the-last four years in the gradation and 30 '
33,. l
-uniformitf of-the backfill have slightly changed the minimum 3
3j~,
and maximum dry density of the backfill, but the liquefaction 3
analysis performed for the ST2 design and presented in the.
36 FSAR was still found to be valid.
37 l 38 The results of, B&R's June 1980 test fill pr,ogram confirm 39.
40 l that: (a) the STP vibratory rollers are capable of compacting 41 l 42,
the specified lift thicknesses to the required densif.ies; 43 44 (b) the compaction throughout the backfill is unifor=; and I
45 !
(c) eight roller passes on. underlying lifts and twelve g
i roller passes on stirface lifts provide satisfactory minimum 48 1 49 ;
EQ 1
i.
- 2. 9 -
~
~;
I l'
s lt compaction criteria to ensure safety.
The Expert committee 4..
.. ~,
confirmed these conclu*sions.
r
~ The Expert Committee's findings as to the quality of i
the STP backfill are presented in a separate piece of testi-f mony.
The Task Force found that relative density tests were not performed on the backfill p, laced for the Essential Cooling Water (ECW) system piping trench as a result of a PTL and B&R QA misinterpretation of the STP specification
[
requirements.
This backfill material, however, was the same as the material placed concurrently in the STP plant area, l
where samples were obtained and subjected to relative density testing.
The tests from the plant area were then used by t
PTL for acceptance of the ECW system piping backfill.
s l
Because PTL used acceptance criteria from the i
plant area, and because the backfill used at STP is especially uniform, the deviation with respect to testing on the ECW area was of no great concern.
Nevertheless, pursuant to a i
program to reexamine welds in the buried ECW pipe, the l
backfill in the ECW trench is being removed to uncover the i
pipe.
Backfill below.the pipe will be tested and relative l
l density tests will be performed during replacement of the backfill in the trench.
Q. 19 Mr. Pettersson, Mr. McKay and Mr. Logan, were-l l
any programmatic changes made in the STP backfill QA/QC
!O I
---w.,wn.
e.------
--=e
-n- - - -, - -
=m---wwv mw--
.6 f.
~
1 2
1i program as a result of the Show Cause verification acuivities?
.-l
. If so, please explain those changes.
5 6
7i A. 19 (CBP, WSM, TKL):
Included in the B&R/E&P Task g' '
Force studies was a review of the PTL EIR's to determine 10 whether the inspection activities meet applicable specifi-11 1 1
12 i cations and procedures.
While the sequence of backfill
~
13 '
14 construction could be established from these records, the 15,
~
16 :
Task Force uncovered several deficiencies in the EIR's 17 i
' ig ;
including inconsistent or missing test numbers, test 19 '
1 cations and dates, and a failure to document certain 20 t
22 [
completed lifts, compaction efforts, and ratests.
21 23 !
The Expert Committee concluded that the foregoing
( 24 !
t 25 deficiencies are of no technical significance.
Nevertheless, 25 46 i B&R issued Corrective Action Requests (CAR's) on these matters 29 l to assure that the quality control records for future backfill
' 30 '
ni construction will provide self-supporting evidence of the 32
, 33 adequacy of the backfill.
Specific corrective actions to be 34 !
implemented include amplified reporting for work in progress, 35 36 !
37 !
logsr for tracking work requiring remedial' action, systematic 38 !
verification of loc,ation descriptions, advance inspection 39 !
40 l schedules and control of reporuing, and indoctrination of 41 i
~
42 i PTL Inspectors regarding the necessity of filling out accurate 43 l y
and complete reports.
- q. 20 Mr. Hedges., what is your professional. opinion of the testing and overall qualitf of the in-place cackfill at 48 49 I STP7
.G0 i V
l l
,,, ~ _, _. _
_,.._,_m-.
,-,_~.__--,___,______.,-~_._,--y--......__-.
c-
I.
L, g,
3 A. 20 (Csa):
The in-place backfill at STP is generally
)
i y;
of equal or higher quality, has a more consistent gradation 5 !
7i and is. more highly compacted than backfill I have evaluated i!
9l st other nuclear power plants.
In addition, the high density 3
achieved gives the STP backfill a factor of safety well Ll I!
beyond the design requirements.
3!4' The STP backfill testing and inspection program has 5l 6l been well-planned from its inception, and provides for more 7i gi frequent and systematic field and laboratory tests than i
9i programs I have observed at other nuclear power plants.
g, 1
Q. 21 Mr. Pettersson and Mr. Logan, what is the present 2
3l status of the backfill program at STP?
14!
5i A. 21 (CBP and TKL):
The backfill construction activi-6 ties at STP have continued uninterrupted.
Backfill placement 7
g>
9 and compaction for Category I areas, including the ECW D!
b system piping, is 75% completed.- Approximately 560,000 yards of backfill have been placed for the Units 1 and 2
~
Roactor Containment, Fuel Handling, Mechanical-Electrical Auxiliary and Diesel Generator Buildings.
Approximately O;
20,000 cubic yards remain to be placed in the main plant pf area, and 120,000 cubic yards remain to be placed around the l
ECW system piping.
All future backfill activities will b'e performed in accordance with the amended specifications and procedures, and w11.1 be monitored closely pursuant to B&R's.
QA program to ensure compliance with applicable specifications.
Oi These activities also will be audited by saa and at&P.
0' 1
TH:10 E j
l".
-n-l l
_