ML18025A610
| ML18025A610 | |
| Person / Time | |
|---|---|
| Site: | Susquehanna  |
| Issue date: | 06/14/1977 |
| From: | Curtis N Pennsylvania Power & Light Co |
| To: | Parr O Office of Nuclear Reactor Regulation |
| References | |
| 150-1, 840-2, ER 100450, PLA-177 | |
| Download: ML18025A610 (6) | |
Text
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'iud, U.S. NUCLEAR REGUI ATORY COMli
)N (oC NRC D!STRIBUTION FoR PART 60 DOCKET MATERIAL DOCKET NUMBER FILE NUMQER ro:
Mx. Olan DE Parr FROM:
Penna Power
& Light Company Allentown, Pa.
Norman V. Curtis DATE OF DOCUMENT 6/14/77 DATE R ECEIVE D 6/17/77 K@LETTER QOR IGINAt Q cop Y DESCRIPTION ENOTORIZED IsImiUNCLASSI FIED PROP INPUT FORM ENCI OSURE NUMOER OF COPIES RECEIVED Ltro notorized 6/14/77
~ ~ o.trans the following:
Consists of additional information relative to their previous x'equest to establish a cold weather concrete freeze-'protection period of three days.,
ECKNOWj33ogg pLANT iiapu,: susquehanna 1 & 2 DO NOT RFr 'ZQVg RJL 6/20/77 Cl I 5'rrs'-I a.
PF-R P. M.
FOR ACTION/INFORMATION ENVXRNNMENTAL JECT AiANAGER:
i~;FLENSING ASSXSTANT:
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'ROJECT MANAGER:
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ENVIRON ANALYSIS DENTON & MULLER ENGINEERING IPPOLITO OPERATING REACTORS ENVIRO TECH ERNST BALLARD YO TGBLOOD.
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TWO NORTH NINTH STREET, ALLENTOWN, PA. 18101 PHONEs (215) 821-5151 JUN 14 1977 6
ow Director of Nuclear Reactor Regulation Attention:
Olan D. Parr, Chief Light Water Reactors Branch No.
3 U.S. Regulatory Commission Washington, D.C.
20555 Docket Nos.
50-387 and.
50-388 co SUSQUEHANNA STEAM ELECTRIC STATION COLD WEATHER CONCRETE SPECIFICATION ER 100450 FILE 840-2, 150-1 PLA-177
[-IItegulatory Docket File
Dear Mr. Parr:
In accordance with a telephone discussion on June 1, 1977 'between your Messrs.
S. Minos and C. Tan and our Messrs.
R.
McNamara and W. Barberich, we are submitting additional information relative to.our previous request to establish a cold weather concrete freeze-protection period of three days
~
The Portland Cement Association, in their Bulletin entitled "Cold-Weather Concreting" (copy attached) includes the following general requirements "Fresh concrete must be protected against the disruptive effects of freezing.
This danger exists until the degree of saturation of the con-crete has been sufficiently reduced by the withdrawal of mix water in the process of hydration. If no water is available from outside the concrete (curing water, for example), the time at which this reduction is accomplished will correspond approximately to the time at which the concrete attains a
compressive strength of about 500 psi."
In addition, ACI306-66, Par. 1.10.1 states "Prevent damage to concrete from freezing and thawing at an early sage.
The degree of saturation of freshly-placed. concrete, which has no access to an external source of water, will be reduced as the concrete hardens and water is used. in the hydration process.
Under such conditions, the time at which the degree of saturation becomes reduced. below the level which would cause damage by freezing corresponds roughly with the time at which the concrete attains a compressive strength of 500 psi.
At temperatures of 50 F most well proportioned. concrete will reach this strength sometime during the second day."
77f7ioi3sT'ENNSYLVANIA POWER 8
LIGHT COMPANY
4 J
With reference to our Susquehanna concrete mix test program to determine the effects of freezing and cold weather curing on strength, we are enclosing a copy of the test report, as prepared by Bechtel Corporation, which supports the above-mentioned statements.
The two concrete mixes which were tested were designated.
C-1P and C-2P.
These mixes were pro-portioned to give a design strength of 4,000 psi at 90 days.
The normal experience on production tests in that these mixes will develop at least 5,000 psi at 90 days.
They are the two most frequently used mix designs for pro)ect Category I structures.
The primary purpose of this test was to verify that the Susquehanna concrete mix designs behave in the same manner as indicated by the above-mentioned predictions.
This purpose was accompli, shed and. the expected results were verified.
We trust that this additional information addresses your concerns, and that you will find the proposal for three day freeze protection to be acceptable for this prospect.
Norman W. Curtis Vice President-Engineering and Construction Sworn to and subscribed before me I I77",
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Notary Public r My Commission expires, li ~
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