ML19208C799
| ML19208C799 | |
| Person / Time | |
|---|---|
| Site: | Wolf Creek  |
| Issue date: | 08/31/1979 |
| From: | Varga S Office of Nuclear Reactor Regulation |
| To: | Moody C AFFILIATION NOT ASSIGNED |
| References | |
| NUDOCS 7909270519 | |
| Download: ML19208C799 (2) | |
Text
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UNITED STATES NUCLEAR REGULATORY COMMISSION k
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I Docket No. STN 50-482 AUG 311979 d kWE ll i:,i/dI
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- i Ms. Chri s R. Ecedy u
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Dear Ms. Moody:
Your mailgram of June 29, 1979, to Mr. Harold Dente. concerning the concrete in the base mat at Wolf Creek, has been referred to me for a reply.
In your mailgram, you express concerns and raise questions regarding the strength of the concrete and request an independent study on the matter.
The matter of the concrete strength of the Wolf Creek base mat dealt with the fact that the results of tests performed on the concrete at 90 days indicated that scr.e of the concrete batches had strengths of less than the 5000 pounas per square inch value specified by the architect-engineer to meet the design criteria in the Wolf Creek Preliminary Safety Analysis Report (PSAR).
In some cases, the results of the 90-day tests were lower than the results of the 28-day tests.
As a result of the above situation, the Kansas Gas & Electric Company (the lead applicant for the Wolf Creek plant) had a number of strength tests and petrographic analyses performed on the concrete samples originally tested at 28 days and 90 days to detemine the cause of the situation and to determine if the concrete was becoming weaker with time. The applicant concluded that the results of these tests and analyses indicated no signs of substandard concrete, inadequate mixing or adverse chemical reaction, or that the concrete was getting weaker with time.
At our request, an independent petrographic analysis was also performed on the concrete samples by the U. S. Army Corps of Engineers. The results of the analysis performed by the Corps of Engineers agreed with the applicant's results.
Additionally, the apolicant performed a reanalysis of the base mat, at our request, to detemine if the indicated strength of concrete based on the 9C-day test results would satisfy the design criteria specified in the Wol f Creek PSAR. The applicant calculated this st ength to be 4460 pounds per square inch as compared to the 5000 pounds per square inch value criginally specified by the architect-engineer.
The applicant then cerferred a reanalysis of the base Cat based on a concrete strength of 4460 ;c cds per scuare inch tc demonstrate that the design criteria in the FSM were met.
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Ms. Chris R. Moody Ayg 3 7 737g We have performed an evaluation of the Wolf Creek base mat, including the tests and analyses discussed above. The results of our evaluation were issued in a docur: tnt, dated July 12, 1979. A copy of this document is encl (sed for your information. As stated in the document, we conclude that The base mat concrete strength has not retrogressed, that the strength of the base mat meets the original design criteria in the Wolf Creek PSAR, and that the mat will withstand the specified design loads and loading combinations without irnpairment of its structural integrity or its safety function.
I am pleased to have had this opportunity to respond.o your concerns and your request.
Sincerely, h
b arh
'A g Assistant Director for Li_ t Water Raactors Division of Project Management
Enclosure:
As Stated
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