ML19323G608

Forwards Detailed Description of Tranverse Fault Beneath Essential Svc Water Spray Pond One Per 800502 & 09 Telcons. Fault Is Not Judged Capable Per App a to 10CFR100

ML19323G608
Person / Time
Site:	Phipps Bend
Issue date:	06/03/1980
From:	Mills L TENNESSEE VALLEY AUTHORITY
To:	Harold Denton Office of Nuclear Reactor Regulation
References
NUDOCS 8006060370
Download: ML19323G608 (4)

Text

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TENNESSEE VALLEY AUTHORITY CH ATTANOOGA. TENNESSEE 374o1 400 Chestnut Street Tower II June 3, 1980 Mr. Harold R. Denton, Director

• Office of Nuclear Reactor Regulation U.S. Nuclear Regulatory Commission Washington, DC 20555 ,

Dear Mr. Denton:

In the Matter of the Application of ) Docket Nos. STN 50-553 Tennessee Valley Authority ) STN 50-554 In a May 2, 1980, telephone conversation, Don Sells of your staff was notified that an additional fault had been discovered at our Phipps Bend Nuclear Plant in the area of the unit 1 essential service water spray pond. A conference call was subsequently made to the NRC geologist, Dick McMullan and the Hartsville project manager, Dino Scaletti, on ,

May 9, 1980, to discuss the fault. The enclosure provides a detailed description of this feature.

We do not consider this minor fault to be capable within the meaning of Appendix A to 10 CFR Part 100.

Very truly yours, TENNESSEE VALLEY AUTHORITY

. M. Mills,, Manager Nuclear Regulation and Safety Enclosure 8006060 3 %

An Eaust Ooportunity Employer

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e l PHIPPS BEND NUCLEAR PLANT Transverse Fault Beneath Essential Service Water Spray Pond Number One Excavation for the Number One Essential Service Water Spray Pond has exposed a transverse fault in the south portion of the Pond. The fault is located approximately 100 feet south and 136 feet west of the intersection of the major and minor axis. This fault is designated as fault 19 on the accompanying map.

The fault trace is defined by a weathered zone approxi-mately eight inches wide striking N 42 degrees W and dipping near vertically. Bedding is offset (right lataral movement) a maximum of eight inches as it intersects the fault zone. It extends south under the overburden and north 35 feet into the excavation where it transitionally terminates into a near vertical joint.

As the zone approaches its transition to a near vertical joint, bedding can be traced through the distorted zone without breakage

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of the beds.

The fault can be traced south to its intersection with the overburden quarternary terrace deposits where no deformation of deposits above the top of rock were present.

4 this type of fault has been described in the Phipps Bend Nuclear Plant PSAR, section 2.5.1.1.2-14, as a minor cross fault and is considered by Rogers (ref. 93 PB PSAR) to be commonplace in the Saltville Fault family area (four miles northwest of the Phipps Bend site).

The fault was formed by stress relief due to pressure from the northwest and southeast directions during the formation of the Saltville Fault family (250 mybp). This fault, having been stable for 250my, is not considered to be capable of pro-3 ducing ground offsets or generating earthquakes. Therefore, we do not classify it as a capable fault, within the meaning of Appendix A to 10 CFR part 100.

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