ML19220B907
| ML19220B907 | |
| Person / Time | |
|---|---|
| Site: | Crane  |
| Issue date: | 01/31/1975 |
| From: | Arnold R Metropolitan Edison Co |
| To: | Knuth D US Atomic Energy Commission (AEC) |
| References | |
| GQL-0725, GQL-725, NUDOCS 7904270645 | |
| Download: ML19220B907 (2) | |
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' CST CFFICE 3CX 542 REACING. PENNSVLVANI A 196C3 ELEP"O'JE 015 - 3:9-:C:
JAN 311975 a1 : 25 Dr. D. F. Knuth, Direccor Directorate of Regulat ory Operations Office of Regulation U.S. Atomic Energy Co=ission
'a'ashington, DC 20545
Dear Dr. Knuth:
SU3 JECT: TFREE MILE ISLAND NUCLEAR STATION L3IT 2 DOCKET No. 50-320 CONSTRUCTION PERMIT CPPR-60 By our letter of Cetober 28,1974 (GQL-0428) your of fice was supplied additional informadon on a deficiency in constr tetion at the' 31ree Mile Island Nuclear Station, Unit 2 involving below standard concrete. This letter supplements that report and completes our action on this iten.
Further documentation is available at the site.
Very truly yours, r
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84-01'5 5 0073 S
ENCI.05URE Metropolitan Edisor. Company Three Mile Island Nuclear Station Unit.2 (TMI-2)
Docket Nc 30-320 Construction Permit CPPR-66 Deficiency Report Submittal Pursuant to 10CFRj0,55(e)(3)
Low Concrete Cylinder Test Strengths (Supplement)
NOTE: This report supplements infor=ation provided in the report of the same title forwarded October 28, 1974 (1) Description of the Deficiency The report dated October 28, 1974 erroneously reported that four of six sets of test cylinders were below standard strength when broken af ter 23 days.
In fact, six of the more than forty sets tested were below standard.
Based on the results of 7 day and 28 day break tests it had been concluded that four of the six sete would reach the 5000 psi strength prior to the 90 day break test and, based on the discussion in the October 28, 1974 report, we believe that this concrete is satisfactory. The 90 day test results on these four sees confirm these expectations. The measured 90 day average strengths were 5370, 5470, 5010 and 5400 psi.
The re=aining two test cylinders were not expected to, and have not reached the 5000 psi requirement af ter 90 days. The measured 90 day average strengths were 4750 and 4820 psi. The quantity of cencrete involved in these two pours represents approximately 200 cu. yds. of the 2773 cu. yds. placed between July 22, 1974 and September 13, 1974.
(2)
Safety Enplications In both of the cases in which 90 day strengths did not reach 5000 psi another set of cylinders from the same truckload did exceed 5000 psi.
One set was
=ade at the truck discharge and another at the purge discharge. Swiss ha==er tests performed on this concrete if3 situ indicate compressive strengths in the 5000 psi range. Based on these facts it is our determination that the concrete is of satisfactory quality and that the reason that certain cylinders failed the test requirement is due to their being mishandled.
(3) Corrective Actions The corrective actions described in our report of October 23, 1974 will be performed in order to prevent a deficiency of this type in the future.84-01G