ML19274G104
| ML19274G104 | |
| Person / Time | |
|---|---|
| Site: | Prairie Island  |
| Issue date: | 07/30/1979 |
| From: | Schwencer A Office of Nuclear Reactor Regulation |
| To: | Mayer L NORTHERN STATES POWER CO. |
| References | |
| NUDOCS 7908290646 | |
| Download: ML19274G104 (3) | |
Text
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UNITED STATES
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July 30,1979 Docket flos. 50-28 anQ0-306)
Mr. L. O. Payer, Manager tiuclear Support Services florthern States Power Company 414 ilicollat Fall - 8th Floor Minneapolis, Minnesota 55401
Dear Mr. Mayer:
We have reviewed your submittal dated May 4,1978 regarding potential equipment failure due to degraded grid voltage on the Prairie Island fiuclear Generating Plant, Unit tios. I and 2.
We find that additional information as described in the enclosure to this letter is required in order to complete our revies.
Please provide the additional infomation within 60 days.
Sincerely,
/Wh V
T'l A. Schwencer, Chief Operating Reactors Branch #1 Division of Operating Peactors
Enclosure:
Request for Additional Information cc: w/ enclosure See next page 2008 m)
~L.
79082906 %
Mr. L. O. Mayer t.orthern States Power Company July 30,1979 cc:
Gerald Charnoff, Esquire Shaw,' Pittman, Potts and Trowbridge 1800 M Street, N.W.
Washington, D. C.
20036 Sandra S. Gardeoring Executive Director Minnesota Pollution Control Agency 1935 W. County Road 32 Roseville, Minnesota 55113 The Environmental Conservation Library Minneapolis Public Library 300 Nicollet Mall
~
Minneapolis, Mhnesota 55401 Mr. F. P. Tierney, Plact Manager Prairie Island Nuclear Generating Plant Northern States Power Company Route 2 Welch, Minnesota 55089 Joclyn F. Olson, Esquire Special Assistant Attorney General Minnesota Pollution Control Agency 1935 W. County Road 32 Roseville, Minnesota 55113 Robert -. Nyoo, Jr., Chairman Minnesota-Wisconsin Soundary Area Commission 619 Second Street Hudson, Wisconsin 54016 Clarence D. Fieracend U. S. Nuclear Regulatory Commission P. O. Box 374 Red Wing, Minnesota 55066 2008 224
REQUEST FOR ADDITIONAL INFORMATION PRAIRIE ISLAND, UNITS 1 AND 2 DEGRADED GRID VOLTAGE 1.
State the voltaca setpoint and time delay for the second level of degraded votlage protection. These values, with tolerance, will have to be included in a Technical Specification enange.
Provide sufficient information (voltage drop analyses) to allow our independent verification that the undervoltage protection 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, operation and accident condition) due to automatic on manual starting of large motors, bulk or sequential loading or automatic transfer of electrical loads..The analyses should include conditions when the safety buses 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.
2.
In the Northern C+ctes Power Company's letter dated May 4, 1978, two alternatives a. 2 given to comply with Position 2, of NRC letter dated June 3,1977 (Safety Evaluation and Statement of Staff Positions Relative to the Emergency Power Systems for Operating Reactors). The alternative selected for your final design and the appropriate Technical Specification change must be provided for our review and evaluation.
3.
Describe your design for the case of bus de-energization, load rejection, voltage restoration, and load sequencing, given an onsite power interruption when the diesel generators are supplying power. Also, describe your test scheme and explain how the sequence of events can be verified by testing.
2008 225
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