ML19242D881

Interim Deficiency Rept Re Concrete Voids Behind Liner Plate in Eighth Lift on Reactor Bldg Exterior Walls.Addl Soundings Will Be Made in Three General Penetration Areas of High Stress Regions & Congestion

ML19242D881
Person / Time
Site:	South Texas
Issue date:	08/15/1979
From:	HOUSTON LIGHTING & POWER CO.
To:
Shared Package
ML19242D880	List: ML19242D879 ML19242D881
References
NUDOCS 7908230422
Download: ML19242D881 (12)

Text

. .

INTERIM REPORT ON THE STPEGS RCS N0. I LIFT 8 CONTAINME.T VOIDS INTRODUCTION On June 5,1979, Houston Lighting & Power Company submitted a final report on the void deficiency that had occur"td on the 15th lift of Unit i RCC Containment Shell. This report contained a description of the methods that were used to identify, analyze, and repair these voids. The report also contained information on those actions taken to preclude the recurrence of this deficiency. Prior to the preparation of this final recort, inforr ation was obtained from site personnel which led to the concern that voids might exist in the 8th lift of the Unit 1 RCB Containment Outer Shell. Soundings were begun and it was determined by drilling that voids did indeed exist.

On June 18, 1979, HL&P notitied the NRC that the condition was reportable under the requirements of 10CFR50.55(e). At this tire, a stop work notice was issued for the placement of all concrete in the Unit 1 and Unit 2 RCS Containment Shells. At this time, a significant amount of investigation has been performed towards the resolution of this deficiency; however, the work has not been completed. Thus, this interim report will provide the status of this activity and will provide information on the work yet to be con-pleted, including an estimated schedule for the completion of these activities.

pjVESTIGATION The investigation of this deficiency was two-fold. One facet of the in-vestigation was directed towart determining the extent of the voids. The

, ,) g 721 79032300 N

Interim Report Page 2 other facet of the investigation was directed tceard determining the cause and providing sufficient corrective action 50 that the placing of concrete in the RCS Outer Shells could resume. A logic diagram was prepared so that this work could proceed in a planned and orderly manner. A copy of this logic diagram is contained in Figure 1.

Initially, B&R Construction plac2d a 2' x 2' grid on the steel Containment liner from El. 57'0" to El. 67'0" for the full circumference of the Cen-tainment. The liner was then sounded for the purpose of detecting potential void areas, using procedures that were developed during the investigation on Lif t 15. All of this activity was conducted under Quality Control sur-veillance. This procedure involves tne tapping of the liner using a metal hammer and identifying areas of "non-contact" between the liner plate and tne concrete based upon the sounds as detected by the human ear. The areas of "non-contact" were physically marked on the liner plate and this informa-tion was then transferred to drawings and transmitted for evaluation. Draw-ings of the liner were prepared showing all penetration and liner stiffening systeT;. Based upon these drawings, direction was provided to drill holes -

in the liner plate to determine if the "non-contact" areas were indeed voids.

A total of 153 holes were drilled and investigated. As the result of this investigation,12 areas were identified in which voids existed. The voids .

were tnen explored using probes and a fiber scope to determine tne extent of "non-contact" These void areas are shown in Figure 2. The majority of the "non-contact" areas were attributed to temporary weldrents attached i7^

i{ f , j r. L

Interin P.eport Fage 3 to the liner, normal concrete settlement / shrinkage, and liner movement.

These findings were consistent with the conclusions obtained during the investigatien of the Lif t 15 deficiency.

The investigation to determine the cause of this deficiency and to provide recurrence control for future pours was conducted in the following manner.

A review of the pour packages (which included inspection reports, test data, and non-conformance reports) which were applicable to Lif t S was conducted.

This investigation was performed for the purpose of identifying any un-expected conditions which may have occurred durino the course of the place-ments and thus, could have contributed to the problen. The information obtained during this investigation was conbined with information obtained during interviews with construction and inspection personnel to provide a basis for assessing the procedures being utilized to control the activities during these ccmplex concrete pours. During the investigation to determine the location of the voids, it was ascertained that the voids of significance were located under the horizontal 8" channel and l" x 8" plate stiffeners in the vicinity of added reinforcing steel around penetra? ions. Such areas -

req; ire an additional amount of attention a'd vibration dur'rg the consoli-dation of the concrete. During this pour, these areas were et the cir; oximate 5' mark of the 10' pour and their accessibility for inspection and vibcation wds ocor. As the result of these investigations, it was determined that recurrence could be affected by providing for better accessibility to those areas of congestion where additional inspection and vibration is required, t ,' (, l,lb

Interim Report P2ge 4 and by strengthening the construction and quality control procedures. A list of recorrendations for corrective action was prepared and was reviewed and approved by both Brown & Root and Houston Lighting & Power Companies.

A sumary of these recomendations is contained in Table 1. Construction and inspection procedures and engineering design documents are currently being revised to accomodate for the implementation of these recorrendations.

CCNTIFUING ACTIVITIES Based upon the information obtained during this investigation of the voids in Lift 8, it was concluded that other void areas could exist beneath pene-trations and the 8" channel and plate stiffeners where additional reinforcing steel is located. Therefore, additional soundings will be made in three general penetration areas of high stress regions and congestior. 1) the equipment hatch, 2) personnel air leci , and 3) the main steam and feedwater lines. The current areas of investi 3n.on are shown in Figure 3.1 and 3.2.

The logic diagran and plan for the completion of this activity is contained in Figure 3.3.

The use of alternate rnethods of sounding the liner was investigated. This investigation consisted of reviewing utility reports to the NRC for similar occurrences on the Wolf Creek, Edward Hatch, and VC Sumer nuclear power -

plants. These reports described similar problems and methods of detecting voids benind the liners. The merits and effectiveness of the alternate methods contained in these reports were discussed with industry personnel 7an a jbN

Interim Feport Page 5 directly involved with their use. It was concluded that physically sounding the liner surface and selectively drilling holes to interpret and verify the soundings is as reliable as other more sophisticated techniques used for void detection. To properly interpret the soundings, the gecmetry of the liner stiffeners, penetrations, and a general configuration and congestion of this reinforcing steel must be considered.

At the present tine, activities are underway to resume the placement of concrete in the RCS Containment Shell. Construction and inspection procedures are being revised to upgrade the control of the concrete placenent during the snell placements. In addition, design drawings are being revised to provide for additional accessibility to areas where additional inspection and vi-bration is required. The clar and logic diagram for this activity is also contained in Figure 3.3.

It has been deternined that the methods used to repair the voids observed on Lif t 15 are appropriate and suitable fo use to repair the voids found on L1ft 8. Final evaluation of the material used in the repair of Lif t 15 will te performed after all information relative to the actual Lif t 8 voids -

is available.

It is estimated that this deficiency, including repair, will be closed out on or before January 19, 1980. The final report will be submitted to the NRC within 30 days thereafter.

., ,, e i} I: N l-

TABLE I RCB SHELL CONCRETE PLACEMENT RECURRENCE CONTROL PRCELEM RECOMMENDED SOLUTICN

1. Conc rete-Uni fo rmi :y A. Buy all produced concrete (batch @ 6").

B. Area Engineer to visually moniter slump consistency at hopper.

C. Use of grout at penetrations as determined by Engineering.

D. Aggregate Moisture - Control for coarse aggregate.

2. Preplace ent Planning A. Drawing and meeting on each placement and document.

B. Define workable section on placement plan.

3. Inspection A. Training of OC inspectors.

B. Increase number of inspectors to a to 6 per pour.

C. Advise foreman of inspectors' authority.

D. Have specific vibrator inspector (s) on pour.

4 Equlpment Breakdown A. Back-up equipment, one to one, located at the pour.

B. Preventive Maintenance Progran identified and followed.

5. Access / Visibility Proolem A. Reduce Lift *7 to approximately 6'-0, with channel at top; subsequent lifts to be 10'-0.

B. Selective shear bar relocation to increase accessibility (10'-0 c. to c.).

C. Lighting available on the form.

D. Engineering to review tie attachment at liner for lifts, at top of forn.

6. Fatigue Start by 9:00 or scrap pour.

7. Vibration A. Crew deposit and vibrate simultaneously, -

responsible for each workable section.

B. Pre-training of vibrator operators.

C. Pencil vibrators at eacn work section for inside and outside face and at penetrations (2 pencil vibrators).

D. Vibrators set-up for each section. .

E. Vibrator / Placement Method written by Construction, includina assignment of vibrator operators to each section.

S. Training A. Vibrator-Placement Foreman - one training placement program on tecnnical aspects,

a. 7 'I f, qr e._v

TABLE I Pace 2 B. Vibrator training field class, demonstrating and explaining technique.

C. Meeting with crews prior to placement af ter prepour meeting, Pour Card signed by the forenan.

9. Production Pressure At prepour meeting, inspector (s) explain "how" identified problems are to be interfaced and solved during the placement.

10. Records Document post placement interviews.

W e

b f.

f-

.ar, a-w rTQ-m ,Vp e

Lza C  : r. r 3 == >

E.EI db 9 3 E

CC 15 y< , - - d g

1 .

v. ..

ig. ;_ a;.

. 11 sig r *

,- 3 i' iis i (__d) r  ! . =h, -

-A

e s.zE a(s. =a e5 . (s_). -

Y t==

• I* N 6er$

si

-  :=.

W13 3.. .

• . .. , e W

• . TE. E 3hN 5 Wz IIe = 3;E  %  ;;3 usu _ _! .!

==

. .5 Egg

. h) es a

=**

I 9

• 2[w

~

I E=!: " E . I

==

z - -as* =5 = a w CIS 3 -  :

O.

- */ . o wsC*

• 4w o a

stat oje 4 as Ng_3 2 o < ?,

O4 22 p at /\  !"  !, e e 2 t  != ! !wg $$ 5u E5 eu

>c z

=

I g

I;I

• m 2

=

2

=

2

.s. o o w o. f l 3.a = .

e *w0

- <, .s -

O g. .

5OM OD

• I Mut O I

-d "5  :- I e -. =48 e E2* a ut2o Ov ==

23

• I III  :,

I

G 42u 5 yZ -

a g

• ~

aw E E

ww w 3 I .y c3 > a I k1rt

.: (o) 3.c 52$ **

< 3 -

1 1

a

- oZbcz *

>=

u. -E $ I 3

. "* * := ; a

.2, -s - 3 2or w d 3 I " g s = =. 2 *2 5 => .g (a) U i

=

2*7

==Z9 s  := "w e> d 3

a L= W = a, 3 wg

. e 3  :%e ss I s

6,d w ,

u 2 g - > g d 5 u

• * = . wZ g

w

-Q 3.2. .

• 8 e g_

4 N1r1 g*

m$o .

55l 556 I

g 53 g**u 0

e y o *C ;<llw E

ce == _ g a

• 2 0 33 j O U 2r 2

~EO Uw 3

g u1rt .

(

o uct 8x - O d*g 0 g33

. 3 f

• E 2*sE 2 g fm e

()

t> E 10 0 C C1 ,

• u E C C *e

. 3*-

3 Mitt e O o

.;2=

< " 2 n> g .o s

~*O Cf

.~es -

• 3 . are. I f a. f , e c

.: 0; ! Is. . u .=

s rg E3 ses.2 e. a:S = m ou

• • =

3 r"$ e. -38=, ;s = = 0L um1 a o w v3 22

=

• :==;. e ea

• ._ . t a=

• f =i ;= *a . =m

.c g. ,: a=

ww w H 0

.E 'E 0-995**18 T1.LAJue03 afLAlf AI ccf1 kS9 O ue 11 C

-/ '? LO it:

t

- ... , _ O b

os + g ig E g g i E I s . a_ .s 5

• 8 E I 1I I l__I II III a x

, eed e.=g. rt R

a W-

%~ ~ _.-

e=

ca ~

n 4 ca U S b"'I

~

a e

(4 O

n-l I /

i 1 a

l O

G-q--

Il .

l l C ll u C

4 C

O Q

1 a a 13'0' y o

= - - A.

O e E ,

m

,s-

g. . .j. . . . . . . . . .

, g3 s> ^

e a ~

m l e Jo u s s C

~

C

% s :ss:)

V*.mj$

er ss '

k

<. - M.t I / O OSI _n-Il \s "

- te] . . e V.1 I

~

~

r a s$.1

'S

. .nh 8 n.eesd l 0 t Y

8 2

i ,,

.[. ... . . ... .. . . . ..

as 2 as l  : et .

wi O

-s Ic _P, il 3 l O.' "

$ j a.s .- J f l

v O :..,. -

- ~

!) i:E g2=t ll 4 vici;5 I t anm O O O O O O O O O O O O O g g

. U $ 9 e . N . W 9 M N D h O e v e4 i

A l-'

ti 7at-?

' L. /

je '

5 LIFT e INVESTIGATION .

I

- - - - - - - w - - - - - - - - Way t$0 0 -

,_ _ ___ __ _ _ 4 _- _ _ _ _ _ __._ __ _ _ _

4 _ _ _ - - _ - -

Wie

- ~ - -

- g 438 0 - Wi$

e

- ~

127 0

- W14 847 0 - -

- W13 607 0 974 _ --

- Wu 870 - - - -

['

77 0 .' ,t _ ,,

i N_.2 , Const. y ,

._,-7 ,, ,

er0

?, b ~ **

b H hh f h, _?)_.f,/N I,k "/, '//' '.( 'h, % .h W~,,l4^' h. .'//

a7 0 b$ . S'//A.f_/i l .

J -

0)enin

'h w7 470 WS 370 --

MAIN STEAM - Ws E PMENT 27 0 PERSONNEL - & FEEDWATER - "'

AIRLOCK PENETRATIONS

" W3

(+) 70 _

wa

(-) 30 _ -

ca. wi t

(-) u3 300 320 344 364 0 40 60 80 400 12 0 44 0 66 0 14 0 230 220 240 260 260 20 FIGURE 3.1 x

.n vas n m

4 b Q )tOIQ!

o u e m .m Ydh: Od d]7I,

e t

b

. ~ . .

'01 4 E E s&

.1

-~$

E E E I.s E s 5 .-~I E E E ll l l- l l l \ll III$ R I

3 i- l- a l I W Ns es mO s l NM N mEC -

-2<

s\ =mm bH o. .

\

ij w\\ e I e'

I g

ll >

m

+ -

m c _ a

~

ll U 8

O E

s j 3 ~ m=-il

$ t .t . .{. . . . . . . ..

. p. j .

[

m E$$

my e lI i 8 G t -

a,.,,

o c t--~,

r- ,

-  ! s -s

^

Il I \ x\ 'd. d lI N 2N' ' - NRlNN: N $ =_ ,

Ty L

Ii x'm >M'N g5  :=

1I l N > N' &NTN

, s .s e s s

"=

3_

C

' ' 5 ti l l i l

e g a[T J I

i I

i , cc P m

am, i:

~

.[. .. . ... .. .. .. .

8 l ,

l i I x\\ N N Si n' t ,

i NN4xW NNh\'); $$

5s I! etxN'tMN u nqx x x xxx- '" ,

~

l i"

'l l l i l .

" . .T 2 p. pg $

zzz 774

' O,. f , j !!

VOID PL AN DAIE. 8 9-79 INV E SilG A l lO!J B 1 19 HH19 H I 1 l'8 H 11 19 (Y l S) O*

• 8719 8379 H l l l'8 GHlO/SI)UNO 10LAll Sill!Wil HIPAlH AS Sf'c Clf it O APPHOVE OHit L fil l4 Ht t i vat tlAll gg , ADCIfl0NAL AHLAS hotiS HOL i S SH. Nil H' AN s vi Hos HI OulHE O f til A uO mO O ;_

Pt R F HF A 1 C 3440 "j -

'Q

_ [hW[51] Call 0ie IF at001EED E5T. 14 be5. ESI 5 W AS i

(10 18 191 i NO 8 ib 19 92019 PHOVIOf

SUMMARY

PHOVIDE SUMtP AHY HIPOF,T HiPOHI ON lli i No !! Of4 P! NL IH AllON AHL AS I \ @yyy >

y 'i n pun n ' '

C B 319 9619 fAEA 1-C-3440 Od ,, d b j3 Il g

[N ttPAh05 Llfi 8 [NVf 5f[$4I[QN 10 INCLUC[: L "g^

as a' ICUIPM(NI PAICH AA[ A fif y. 20* to 118*

ti Pla50hhti AIRLO(E ARIA EL EV. 15' to 95*

c' MA14 51LRi/f LEDWATLR LihES FLEW. 40' to 65*

HESUME SHELL CONCHETE 7 77 ?9 8 I 19 CONSI H OCilt)NIO A 0I INCORPOHAIE 10 T H AIN/H1 Vist PHOVIDE FOHM Ill/SHf AH Gull)t L int S PHOCl OU H1 S/IMPl i MI NI R( $ POND LIF i POOR ist /GHOtti GUIDE L INI $ (N f O PHOCl DOHI $ Itt COMMI NDAllONS T Lifi No 7 O >O -O -OO NHCO SWNH3-0 I

8 H 19 81079 s _. I W.4Ni I RIN G CONSIHUCilON Ht VISI Ht Vit w/ Atthuvi F HL A ON LIF i No 7 r; p 'a'^

INCOHPoit AllNG y' , - peniss HE LOMMt NOAllONS _) E N6epse e noseG acarewst y

( ) cale s u son i enva slocaretm nao o NOTE: The dates shown are intended for internal planning and scheduling FIGURE 3.3 only.

g se s

e