ML20129B588
| ML20129B588 | |
| Person / Time | |
|---|---|
| Site: | Beaver Valley |
| Issue date: | 10/18/1996 |
| From: | Brinkman D NRC (Affiliation Not Assigned) |
| To: | Cross J DUQUESNE LIGHT CO. |
| References | |
| TAC-M95689, NUDOCS 9610230056 | |
| Download: ML20129B588 (4) | |
Text
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i October 18, 1996 Mr. J. E. Cross President-Generation Group a
Duquesne Light. Company e
Post Office Box 4 Shippingport, PA 15077
[
SUBJECT:
REQUEST FOR INFORMATION CONCERNING POROUS CONCRETE SUB-FOUNDATION, BEAVER VALLEY POWER STATION, UNIT NOS. 1 AND 2 (TAC NO. M95689)
Dear Mr. Cross:
The NRC has been evaluating the reported erosion of cement from under tne 1
containment foundation basemat of Millstone 3.
The Millstone Unit 3 containment foundation basemat is supported on rock; however, between the rock j
i surface and the underside of the structural concrete basemat there are several layers of material, one of which is a 9-inch thick porous concrete layer 4
consisting of coarse stone aggregates and high alumina cement.
Six-inch diameter porous concrete pipes are installed in this porous concrete layer.to collect and drain ground water.which may seep down along the periphery of the containment wall. The collected water drains into two sumps inside the Engineered Safety Features building. Cement slurry has been observed in these sumps.
Based on our review of the information provided to us so far, there is no immediate safety concern because the amount of cement estimated to have i
possibly eroded since the plant was built in 1975 is only a small fraction of j
the total cement weight'of the porous concrete, and because no adverse i
consequences of the cement erosion are either predicted or have been observed at Millstone 3.
With regard to any generic implication of this issue on other containment foundations with 'similar design, the staff has identified additional plants for which it requires more detailed information, including Beaver Valley Power Station, Unit Nos. I and 2.
Enclosed is a request for additional information (RAI).
Please provide your response within 14 days from receipt of this letter.
Sincerely, L. 01shan /S/ for Donald S. Brinkman, Senior Project Manager i
Nft Do b bo00$34 Project Directorate I-2 l
P PDR Division of Reactor Projects - 1/II Office of Nuclear Reactor Regulation i
Docket Nos. 50-334/412
Enclosure:
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.i October 18, 1996 Mr. J. E. Cross President-Generation Group Ouquesne Light Company Post Office Box 4 Shippingport, PA 15077 SL'BJECT:
REQUEST FOR INFORMATION CONCERNING POROUS CONCRETE SUB-FOUNDATION, BEAVER VALLEY POWER STATION, UNIT NOS.1 AND 2 (TAC N0. M95689)
Dear Mr. Cross:
The NRC has been evaluating the reported erosion of cement from under the containment foundation basemat of Millstone 3.
The Millstone Unit 3 containment foundation basemat is supported on rock; however, between the rock surface and the underside of the structural concrete basemat there are several layers of material, one of which is a 9-inch thick porous concrete layer consisting of coarse stone aggregates and high alumina cement. Six-inch diameter porous concrete pipes are installed in this porous concrete layer to collect and drain ground water which may seep down along the periphery of the containment wall. The collected water drains into two sumps inside the Engineered Safety Features building. Cement slurry has been observed in these sumps.
Based on our review of the information provided to us so far, there is no immediate safety concern because the amount of cement estimated to have possibly eroded since the plant was built in 1975 is only a small fraction of the total cement weight of the porous concrete, and because no adverse consequences of the cement erosion are either predicted or have been observed at Millstone 3.
With regard to any generic implication of this issue on other containment foundations with similar design, the staff has identified additional plants for which it requires more detailed information, including Beaver Valley Power Station, Unit Nos. I and 2.
Enclosed is a request for additional information (RAI).
Please provide your response within 14 days from receipt of this letter.
Sincerely, P
Donald S. Brinkman, Senior Project Manager Project Directorate I-2 Division of Reactor Projects - I/II Office of Nuclear Reactor Regulation Docket Nos. 50-334/412
Enclosure:
RAI cc w/ encl:
See next page
J. E. Cross Beaver Valley Power Station Duquesne Light Company Units 1 & 2 cc:
Jay E. Silberg, Esquire Bureau of Radiation Protection Shaw, Pittman, Potts & Trowbridge Pennsylvania Department of 2300 N Street, NW.
Environmental Resources Washington, DC 20037 ATTN:
R. Barkanic i
Post Office Box 2063 l
l R. K. Brosi, Manager Harrisburg, PA 17120 Nuclear Safety Department (BV-A)
Duquesne Light Company Beaver Valley Power Station Mayor of the Borrough of PO Box 4 Shippingport Shippingport, PA 15077 Post Office Box 3 Shippingport, PA 15077 Commissioner Roy M. Smith West Virginia Department of Labor Regional Administrator, Region I Building 3, Room 319 U.S. Nuclear Regulatory Commission i~
Capitol Complex 475 Allendale Road Charleston, WVA 25305 King of Prussia, PA 19406 John D. Borrows Resident Inspector Director, Utilities Department U.S. Nuclear Regulatory Commission Public Utilities Commission Post Office Box 298 180 East Broad Street Shippingport, PA 15077 Columbus, OH 43266-0573 Director, Pennsylvania Emergency Duquesne Light Company Management Agency Beaver Valley Power Station Post Office Box 3321 PO Box 4 Harrisburg, PA 17105-3321 Shippingport, PA 15077 ATTN:
S. C. Jain, Vice President Ohio EPA-DERR Nuclear Services (BV-A)
ATTN: Zack A. Clayton Post Office Box 1049 Columbus, OH 43266-0149 Dr. Judith Johnsrud National Energy Committee Sierra Club 433 Orlando Avenue State College, PA 16803
RE0 VEST FOR INFORMATION REGARDING CEMENT EROSION UNDER CONTAINMENT FOUNDATION BEAVER VALLEY POWER STATION. UNIT NOS. 1 AND 2 DOCKET NOS. 50-334 AND 50-412 Your plant appears to have a porous concrete layer below the containment basemat.
1.
Have you found slurry in the drainage from this layer?
2.
Has there been any settlement of the containment basemat?
3.
Have you noticed any unusual conditions which may be related to the porous concrete sub-foundation layer?
4.
Are you monitoring anything related to the drainage from the porous concrete sub-foundation layer (s) below the containment basemat?
ENCLOSURE
"