ML19305E284

Forwards Request for Addl Info Re Degraded Grid Voltage. Also Requests Revised Schedule for Submission of Design of long-term Mods Re Adequacies of Station Electric Distribution Sys Voltages

ML19305E284
Person / Time
Site:	Browns Ferry
Issue date:	04/08/1980
From:	Ippolito T Office of Nuclear Reactor Regulation
To:	Parris H TENNESSEE VALLEY AUTHORITY
References
NUDOCS 8004230283
Download: ML19305E284 (3)

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April 8,1980 Docket Nos. 50-259 50-260 and 50-296 Mr. Hugh G. Parris Manager of Power Tennessee Valley Authority 500 A Chestnut Street, Tower II Chattanooga, Tennessee 37401

Dear Mr. Parris.:

Reference is made to your' letters of May 12, 1978 and September 4, 1979 regarding the adequacies of station electric distribution system voltages for Browns Ferry Units 1, 2 and 3.

Your letter of September 4,1979 noted that you were planning to submit a description of the proposed long-term modifications to us for approval in early 1980.

In the interim,.we have reviewed the information in the referenced submittals. -Our comments are enclosed. Within 60 days of receipt of this letter, you are requested to respond to the enclosed request for information and provide the revised schedule for submission on the design of the long-term modifications.

Sincerely, Thomas M. Ippolito, Chief Operating Reactors Branch #3 Division of Operating Reactors

Enclosure:

Request for Additional Information cc w/ enclosure:

See page 2 8004230 2 F3

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r Mr. Hugh G. Parris April 8,1980 cc:

H. S. Sanger, Jr., Esquire Gene'ral Counsel Tennessee Valley Authority 400 Commerce Avenue E 118 33 C Knoxville,. Tennessee 37902 Mr. Ron Rogers Tennessee Valley Authority 400 Chestnut Street, Tower II Cha+tanooga, Tennessee 37401 Mr. H. N. Culver 4

249A HSD 400 Commerce Avenue Tennessee Valley Authority Knoxville, Tennessee 37902 Robert F. Sullivan U. S. Nuclear Regulatory Commission

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P. O. Box 1863 Decatur, Alabama 35602 Athens Public Library South and Forrest Athens, Alabama 35611 4

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REQUEST FOR ADDITIONAL INFORMATION BROWNS FERRY UNITS 1, 2 and 3 DEGRADED GRID V0LTAGE DOCKET NOS. 50-259, 50-260 AND 50-296 Upon review of your submittal dated May 12, 1978, for second level _

undervoltage protection it has been determined that the following addi-tional information is required to complete our evaluation:

1.

Staff position (1)(f) requires that the Technical Specifications shall include limiting conditions for operation, surveillance requirements, trip setpoints with minimum and maximum limits, and allowable values for second level undervoltage monitors.

Staff position 3 states the criteria for testing requirements. of our June 3,1977 letter shows all the criteria of staff positions (1)(f) and 3 in Model Technical Specification (MTS) format.

A review of your Technical Specifications reveals that the criteria will not be met without changes. Please furnish proposed changes to comply with the criteria including loss-of-voltage setpoints, allowable limits and testing capabilities. These changes should also bliow MTS format as close as possible.

2.

Staff position (1)(e) states that the voltage monitors shall be designed to satisfy the requirements of IEEE 279-1971. Confirm that your design satisfies these requirements by documenting and describing such requirements as seismic and environmental qualification, class 1E qualifications, independence, redundant, reliability and testability and others pertinent to the design.

j 3.

Provide sufficient information (voltage drop analyses) to allow our independent verification that the undervoltage protection i

voltage setpoint and time delay selected will not cause spurious separation of safety buses from offsite power during all modes of plant operation (start-up, shutdown, power operation and accident condition) due to automatic or manual starting of large motors, bulk or sequential loading or automatic transfer of electrical loads. The analyses should include conditions when the safety bases are supplied power from the Unit Auxiliary Transformer, the Start-up/ Reserve transformer or other available offsite connections and assuming the need for electrical power is initiated by an anticipated transient (e.g., unit trip) or an accident,,

whichever presents the largest load demand.

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