ML18025A235

Letter Responding to the Commission Letter of December 29, 1977 Regarding Cold Weather Concrete Requirements

ML18025A235
Person / Time
Site:	Susquehanna
Issue date:	01/19/1978
From:	Curtis N Pennsylvania Power & Light Co
To:	Parr O Office of Nuclear Reactor Regulation
References
Download: ML18025A235 (10)

Text

REGULATORY INFORMATION BISTRIBUTION SYSTEM

< RIDS)

DISTRIBUTION FOR INCOMING MATERIAL 50-387/388 ORG:

CURTIS N

N PA PNR 8c LIGHT REC:

PARR 0 D

NRC DOCTYPE:

LETTER NOTARIZED:

YES

SUBJECT:

INFO CONCERNING THE CURING PERIOD AND PROTECTION DURING COLD HEATHER CURING.

BOCDATE: 01/19/78 DATE RCVD: 01/31/78 COPIES RECEIVED LTR 1

ENCL 0 FROM FREEZING OF CONCRETE PLANT NAME:SUSQUEHANNA UNIT 1

SUSQUEHANNA UNIT 2 REVIEWER INITIAL:

XBT DISTRIBUTER INITIAL:

DISTRIBUTlON OF THIS MATERIAL IS AS FOLLOWS +++++++>++~+>+>>>+

PSAR/FSAR AMDTS AND RELATED CORESPONDENCE (DISTRIBUTION CODE 8001)

FOR ACTION:

lNTERNAL:

EXTERNAL:

ASST DIR VASSALLO++LTR ONLY<i)

PRO J MGR MINER++LTR ONLY(1)

FG FIL LTR ONLY(1 >

I 4

++LTR ONLY<2)

P.

COLLINS++LTR ONLY(i)

HELTEMES++LTR ONLY<i)

MIPC>>LTR ONLY(1 >

BOSNAK+~~LTR ONLY< 1)

PAWL ICKI++LTR ONLY(2>

NOVAK4+LTR ONLY<i)

CHECK++LTR ONLY(i>

BENAROYA<+LTR ONLY(1)

IPPQLITO++LTR ONLY(1>

GAMMILL4~+LTR ONLY(2)

BUNCH~~LTR ONLY(1')

KREGER44LTR ONLY(1)

LPDR'S WILKES BARREi PA++LTR ONLY(i)

TIC++LTR ONLY<i)

NSIC++LTR ONLY(1 >

ACRS CAT 8+4LTR ONLY<16)

BRANCH CHIEF PARR<4LTR ONLY< 1)

LIC ASST RUSHBROOK+>LTR ONLY(i)

NRC PDR%%LTR ONLY(i)

QELD44LTR ONLY(i)

HOUSTON++L'TR ONLY(i>

CASE44LTR ONLY< 1)

KNIGHT~~LTR ONLY(i>

SIHWEIL++LTR ONLY< 1)

ROSS++LTR ONLY(i>

ROSZTOCZY++LTR ONLY<i)

TEDESCO++LTR ONLY(i>

LAINAS4+LTR ONLY< 1)

F.

ROSA+4LTR ONLY(i>

VOLLMER4+LTR ONLY(i)

J.

COLLINS+>LTR ONLY(i>

KIRKWOOD++LTR ONLY< 1)

DISTRIBUTION:

LTR 54 ENCL 0 SlZE:

4P THE END CONTROL NBR:

780310167 4%%44%44444%4%0I44%%%%%%%%%$

.Pt/

1 l,

2

't PPslLg@(~-,I>>,.f p I,~~

TYPO NORTH NINTH STREET. ALLENTQTTN, PA.

10101 PHONE, (RIEL 021-2121 MR January 19, 1978 Director of Nuclear Reactor Regulation Docket Nos. 50-387 50-388 Attention:

Olan D. Parr, Chief Light Water Reactors Branch No. 3 U.S. Regulatory Commission Washington, D.C.

20555 "w ~>s>)y~

+/@4 80~

fO~

SUSQVEHAKVA STEAM ELECTRIC STATION COLD WEATHER CONCRETE REQUIREMENTS ER 100450 FILES 840-2 5 150-1 PLA-210 We have received your letter of December 29, 1977, and note that your staff agrees with our proposal to provide a minimum period of 3 days for protection of concrete from freezing.

However, there has obviously been a misunderstanding by your staff of the state-ments in our letters regarding cold weather curing of concrete.

We assure you that we did not have "... the misconception that freezing protection and curing of concrete are one and the same..."

This is a misleading conclusion apparently drawn from the combined statement of PROPOSAL in our letter of March 30, 1977, our letter number PLA-168, which is worded "Proposal Co reduce the minimum required period of curing and. protective measures for concrete

members, 22 feet or less in the least dimension, during cold weather, from seven days to three days and. the requirements of Table 1.4.2 of ACI 306."

We particularly must take exception to the accompanying staff statement which reads "Because of this misconception, the stipulations in various ACI specifica-tions have been erroneously interpreted as indicated in the following comments...".

Freeze protection and cold weather curing during the first few days must occur within the same environmental space and must occur simultaneously.

Freeze protection of concrete is defined. as the implementation of procedures to ensure that the water in freshly placed. concrete does not crystallize due to freezing prior to the time when the concrete has attained a strength level of 500 psi.

ACI 306<<66 recognizes this, as we previously stated in our letter of June 14, 1977.

~Curds of concrete is defined as the protection of new concrete from dryi'ng oue so that adequate, hydration may be a'chievede P E N N S Y L YA N l A P 0 W 8 R 8

L I G H T C 0 M P + td 'SP-780310167 The rate of hydration which takes place in new concrete generally determines the rate at which the concrete will gain strength, all other mix design features being equal.

Hydration is primarily influenced by the cement content, heat, and JOETP f~

,(o

~ Ef Affj

. ~Etfhrf r

r (r),

-'-KE 1

~ r rfr hu E,<,

r ~hh 1

ht t>>

~ s l t',

t1 fr l,

r f nhr yr Af t

~ '>t 'f rh lg lf>>r>> f I'

nfl f Tf-r r

\\t" Ar r l

E n

f A

I rn

(

f jS I'l>>h>>

fll C*EA I

1 f

1 s

rf sf ffs

~ tt

>>A f- -f r ntf

'I

~

~

h h ~

\\ g

<<t ~

8 r.

h

~

~

l

=l I

~

~ f

~

1

~ft r

1=

h>>~<<

f" s>>th fP ~"

~f Af,sr'f, f

r, f rfft

~ y.

r t

lP "f-rtst

~

s +-h h f r

~

11

~

~

Ir r rf',

>> - f rhf( rs'r

~ frf>>

r rhf 'r t

• ff f

t h

~

h

~ t

~,( <<J' r>>

s

~

t

~

sh A

's A

Affll P,

hf s)

> ther

'>>ff

'I r r>>

Art(

Ar l

~.1 f'tf

>Ad Eh s f ry(

f t ~

1

=I (s

A(f h r

"f' r-

~

~ - >>~f

">>s t" r+

E r

1 h

~

1 Af Q A

t l frrh

"'f

>> rr

~

~

A At

'I-r 1

l>>

ff 1>>

r>>

t'-

~

f h

(

>>r

~ I a

t- '

~

r

'*h>>,

ht

Page 2

water content in the freshly mixed concrete.

We reiterate the statements of ACI 306-66, Chapter 9, COLD >RATHER CURING REgUIREZENTS AND METHODS:

1)

Paragraph 9.1:

"It is essential that new concrete in all weather be protected. from drying out so that adequate hydration may be achieved.

This requirement normally means that positive measures must be, taken to prevent excessive evaporation of moisture from concrete.

During the winter however when the air temperature is below 50 F 10 C

, atmospheric conditions in most parts of the country are such that undesirable dryin will not occur.

Furthermore, new concrete is vulnerable to freezing in a saturated condition.

Therefore, all concrete should-be allowed. to undergo some drying before being exposed to freezing temperatures."

2)

Paragraph 9.2:

"Although concrete exposed to cold weather is not likely to dry out at an undesirable rate, particular attention should. be given to concrete that is undergoing the protection required by Table 1.4.2.

As long as forms remain in place, surfaces adjacent to the forms are adequately cured in cold weather...".

We have restated these fundamentals because we wish to make it perfectly clear that we have no misconception about the similarities or differences in the requirements for protection from freezing and/or the requirements for cold weather curing.

We have been placing high quality concrete - generally much higher than required by existing codes and regulatory requirements - since the beginning of our construction project in 1973.

We have no desire to reduce this high quality standard - either now or in the future.

However, when we have sufficient evidence that supports an improvement in field. procedures and the implementation of this improvement will meet regulatory requirements as well as reduce project costs, without sacrificing the high quality of our

concrete, we are obligated in the interest of maintaining our costs as low as possible, to implement these improvements.

We strongly believe that a minimum cold weather curing time of three days is, 3 6.66!

9, to Paragraph 9.3, "Following the removal of the temperature protection, no positive measures to prevent excessive evaporation are required as long as the air temperature remains below 50 F (10 C).

An exception is coscrete 0

placed in extremely arid regions where the relat)ve humidity at 50 F (10 C) may be expected. to be below 40 percent and at 40 F (4'5 C) below 60 percent...".

Weather records from the AVOCA, Pennsylvania Airport weather station confirm that the average winter humidity for the region near our project job site is above these minimums and. meets the requirements of this specification.

We have submitted extensive test data to verify that our own project concrete mixes will comply with the curing requirements of ACI 306-66, Chapter 9 when

Ital(

. 'f~,,AJ( nst

()t r

4

~ )('

)

6 (r

r'

(

4'AM 4

~

)N

~

A

~

~ '

"(

1 ~

'1 ~

1 'I 1 J

~

~

~ "'p '>>

g rl 1

>>In 1 4*n vt

\\f Jg

'I

()1

>>A

~

~ I 1

6 1 r Jk

'1 ~

g 't,g J ff(

Jnt

\\

I n II n ~ \\

(f

~,,

-Anrr I (n'lr,r 6) ~

l 1 rlr

~ 4 1 >>f~

1 I

nr C

AI I "'ran ln

)

(n

(

'n A(f I\\

j "

..In t,fl'f>>.,

r(A '(I q

- (( f rrr 4

6

Iltl, lr t

~

(/4>>

$ FM'-nf(r)r,fA r>> ~ n nf

~

p

'l

(

s

~

~

~

~

~.A f(

~ ~

nt n'4 6,')'

~

6 4

>>r)

~l (n 4

>>A( r jJ II<,

~

sl=lrtt '

~ lr I g r '1 II tf)

~ I 6

6

(

I A%.>>A 6 I I

C 6'('

~

f,

( fsfnnrr I ~

Ir)f 6>>n 6 '

n t

ra Jr f t "ff Jl A At I

~ F It

'I 4

~ >>6 IV) ff (P 'ln II F

I a

n

>>gr J n

~ -r

\\

-rf>>

,. nttf 1

o JI

~

kt

\\

~ '

lf r

(

tl C

~ I

~r(ft 6

I "ar' n

6 I 1

t A ~

~

A

~

4 nfrJ n T))4 6

rs

• -n) f f>> I

~

r 6

6 6

C ta rgtlrl

(

', 6

~ 1 I

J

~

-'last F'

tts-Hn noser) 6\\4 6 6

A nf 1

4 F I4 64

O.

K

\\

< ~

~

cc-Messrs:

R. W. McNamara H. L. Harris J. R. Schmiedel M. R. Muir R. J. Shovlin W. E. Barberich E. M. Mead A. M. Male A. R. Sabol J.

W. Geiling G. E. Shamis Letter File

'<<5 Susq.

SES Bechtel Bechtel N-4.

N-4 N-5 N-5 N-4 N-5 N-2 N-3 NWC/RWN/oaf

~

~

~ t JI 5

~,

C't

=, ~

1 h

II )

w 1

I

~ g f

h P

~

~

Page 3

cured for the minimum 3-day period.

Although ACI 301-72, Chapter 12, refers to a minimum concrete curing -period of 7 days, it also refers to ACI 306 for detailed recommendations concerning cold. weather concrete curing procedures.

We have previously submitted justification to you for the use of flyash in our concrete and the establishment of. a minimum curing period of 7-days for massive structural -concrete, as well as other specific design requirements supplemental to the ACI 301-72, ACI 306-66, and, ACI 318-71 specifications.

These modifications have been approved by your staff, PSAR changes have been submitted, and the field construction work is being performed. accordingly, as verified by your compliance inspectors.

Please refer Co our letter (PLA-70) to NRC dated July 1, 1975.

Amendment 417 to our PSAR, dated, March, 1975, Paragraph 5.2.5.1

d. states "Admixtures shall conform to ASTM C-618 for pozzolans...".

Almost all of'ur concrete, since the beginning of our pro-ject concrete work in 1974, has contained pozzolan (flyash) and has a design strength specified to be attained at 90 days.

PSAR Amendment No. 16 dated November 11, 1974, contained this specification, but it was inadvertently omitted from subsequent PSAR Amendments.

It has been incorporated, into the PSAR Amendment No. 20 which was submitted recently.

We request that you review the above mentioned considerations, including the intent of ACI 306-66, and concur with our proposed minimum cold weather curing period of 3-days for the Susquehanna Steam Electric Station Project concrete.

This procedure is also subject to the conditions of Paragraphs 9.3 and. 9.4 of ACI 306-66.

If you would like further clarification or justification for our statements on cold weather curing of concrete, we would be happy to discuss these with you, either by telephone or in a meeting at your convenience.

Very truly yours, Vice President - Engineering end Construction S'w'n to end subscr ed before me this otary Public rc '71 My commission expires:

xmas 3'0

.. "'.-, -- DAVIDM. LANDIS, Notary Public Allentown, Lehlgh County, Pa.

MyCommission Expires March 16,19'f pa~~~

, 1978.

g

~( Il fy e'ef g

< v (

efe e,e I<

I ei fl n

l+

')e r r

I e

nf* ~

()

e fe)f e

ee r

I(f nfl

+,e

e e "'f n

, ~e

'I "

~

~

I*" L'"'

f 'n" l'

"I "

>>('<ee " '>

- f.'(

" ".f'l.,'(((f '

"((

n*n,e feg e,

I

~, l,\\I <M

<r

~ I

,)

(

n.

~

f f

lf

() ')

I J

I.

(

e ~

, e l l

~

II n f wet't e

+nf)

I f' f"~

0>>

f,r, I" f

',.f

(

L fe,*!

f.ef ttt

(

~

(

, T

~

(

<<,>> ,Itf>>(1

. ~ c "r.e

~

f '

r frn fh I"

f fe<.

(

~

'I

~ e nt I

>> ~ ( 8(

~ <

~

~

. r n

II )I.

4 1

~ 4

~

~.

f"

~

l f(

~

I r

yf I

frn e

( (

I

\\

= ~

g)

<e( ( n

)C

~ ~

4 e eyn >,

n I

I I rlee r.e n J 1

~ I U

>>t 'Il 1

e

) lfee lf

.r f

((

r t*nt I r)ee e) ff((h

~ ('r<'

'<<r <<f1

~'f'

\\

~

0f,r,

)

\\

tl r ~ -e

~ r e ~

e )

Cgg.

~ >

~

>>j ef<

~

\\

~

eI

~ e e

e'l(eee j

r

~I