ML19250A104
| ML19250A104 | |
| Person / Time | |
|---|---|
| Site: | Crane  |
| Issue date: | 04/13/1971 |
| From: | Howard E US ATOMIC ENERGY COMMISSION (AEC) |
| To: | Henderson J US ATOMIC ENERGY COMMISSION (AEC) |
| References | |
| NUDOCS 7910160608 | |
| Download: ML19250A104 (2) | |
Text
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.APR131971 J. B. Henderson, Chief, Reactor Construction Branch, Division of Compliance, HQ INQUIRY IIMOPJ.NDLS!
1ETROPOLITAN EDISO:t CO'! pal f (Ii! PIE MILE I. LWD UNIT No. 1), 289/71-A CONCPITE FOUR UHEN TIE lEl 3UPID SURFACE TE!!PERATURE IN C0:7 FACT WITH TIE CONCRETE WAS IISS T1!AN 32 F On January 8,1971, approximately 230 cubic yards of concrete was placed in a fuel handling. building wall at cicvation 331 to 346 feet running north and south from 17 feet west of the reactor centerline.
At the time of this placement the measured surface tecperature of the surfaces to be in contact with the concrete was below 32 F at the beginning of the sche-duled pour.
The concrete placement under the conditions stated above is contrary to Volume II, Sectica 5 of the FSAR which invches ACI 318-63 and 301-66.
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CDM was issued by C0:I and answered by the licensco as the intended cor-rective action, uhich was considered adequate.
Subsequent to the issuance of the CDN and tt.c licensee's reply, four coro samples were recoved from the fuct handling building vall along the joint between the concrete belou 32 F and the 230 cubic yard scheduled pour for evaluation. Those sampics ucre designated Tcla, TC2a, TC3a and TC4a.
The dimensions of samples No. TCla and TC4a which were damaged during rer.nval are not recorded in the PIL Test acport, PG-2642, dated March 19, 1971, nor other availabic documentation at Three Mile Island.
Sacple No. TC2a was 3.75 inches in diameter and the capped icngth was 7-1/2 inches. The sampic was tested for compressive stronrth and failed at 4050 psi. The direction of loading was para 11c1 to the construction joint. The age of the sampic was nine weeks.
(Unit No. 1 FSAR, Volu=c II, states that Clasa I concrete will have a minimum strength of 5000 psi at 28 days.)
PTL Test Report No. FH-87, dated February 10, 1971, states that the test cylinders uere seven-day moist cured and the balance of the curing period was in air. All ten of the test cylinders taken during the 230 cubic yard pour failed at r.reater than 5000 pst during the compressive strength tests on the 28 day old cylinders.
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2-4 Sample No. TC3a was 3.75 inches in diameter and the length was reported to be 8.12 inches. The splittin2 tensile strength of the ca=ple was 395 psi.
A double split occurred during the test simultaneously, one in the construction joint and another approximately 1/2 inch from, but parallel to the construction joint in the adjacent concrete.
The age of the sa=ple was nine weeks.
All four samples were examined under 10 power magnification at the bonded and fractured surfaces to determine any signs of freezing.
There vere no frost prints or other indications of freezing which would adversely affect the concrete bond.
The licensee sected that the wall was accepted on the basis of FIL's " Test and Evaluation Program", Order No. PG-2642, dated March 19, 1971, and a research paper by T1NES entitled " Investigation of !!ethods of Preparing Horizontal Construction Joints in Concrete" Technical Report No. 6-518, U.S. Ar=y Engineers, Ualenway's Experimental Station, published in July, 1959.
Since one ' sample was ce=pression tested and one sempic was tensile pulled, chere appears to be no basis on which to accept or refute a one sample evaluation.
e Further, no sample cores were removed frem the central por-tion of the five foot thick wall for evaluation, and cores verc not taken from previously accepted concrete pcurs for co=parison and evaluation.
Apparent-ly Met Ed has no plans to take additional samples for evaluation and/or comparison.
E. M. Howard CO:I:DMH Senior Reactor Inspector cc:
E. G. Case, DRS (3)
P. A. Morris, DRL R. S. Boyd, DRL (2)
R. C. DeYoung, DRL (2)
D. J. Skovholt, DRL (3)
P. W. Howe, DRL (2)
A. Ciambusso, CO L. Kornblith, Jr., CO R. H. Engelken, "O Regional Directors, CO 1408 5
REG File 9
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