ML19256A291
| ML19256A291 | |
| Person / Time | |
|---|---|
| Site: | Browns Ferry  |
| Issue date: | 11/20/1978 |
| From: | Fox H TENNESSEE VALLEY AUTHORITY |
| To: | James O'Reilly NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION II) |
| References | |
| NUDOCS 7811280214 | |
| Download: ML19256A291 (2) | |
Text
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TENNESSEE VALLEY AUTHORITY CHATTANOOGA. TENNESSEE 37401 Nov ember 20, 1978 Mr. James P. O'Reilly, Dir tor U.S. Nuc ar Re,ulatory armission Offic of Inspec fon nd Enforcement Rep n II 1
Itarietta Street, Suite 3100 tlantr., Georgia 30303
Dear Mr. O'Reilly:
TENNESSEE VALLEY AUTHORITY - BROWNS TERRY NUCLEAR PLANT UNIT 1 - DOCKET No. 50-259 - FACILITY OPERATING LICENSE DPR REPORTABLE OCCURRENCE REPORT BFRO-50-259/788 The following is a supplement to my letter dated March 31, 1978. The subject reportable occurrence / scribed potential adverse conditions on inplant voltages resulting from higher than designed real and reactive loads and the resulting voltage drop across the high impedance common station service transformers.
Interim corrective measures have been taken to alleviate potential ad'rerse inplant voltage conditions. These interim corrective measures consisted of:
1.
Connection of unit 3 4-kV unit boards to cooling tower transformers as a source of supply.
2.
Installation of a 42-:fvar and a 39-Mvar capacitor bank on the 161-kV systaa to improve power factors under high inplant load demand situations.
3.
Second-level undervoltage protection is to be installed on the 4-kV shutdown boards to ensure that upon a voltage degradation, the shutdown boards are supplied from an onsite power system, i.e.,
diesel generators.
Items 1 and 2 were completed June 12, 1978, before the unit 2 startup from the refueling outage. Since these modifications were completed, we have had various unit shutdowns including one event with three units shut down at the same time.
During these events, all inplant voltages were well above the minimum required.
Item 3 is being reviewed and is presently scheduled for installation on unit 3 this outage and on units 1 and 2 during unit 1 outage scheduled for November this year.
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78 // M D'i k
An Equal Opportunity Employer
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Mr. James P. O'Rei ly, Director Nov ember 20, 1978 Our Division of Engineering Design is presently evaluating further permanent modifications to ensure that, under all plant conditions, inplant voltages are maintained to acceptable levels. This evaluation is indicating that the installation of generator breakers on the individual units is a viable permanent fix.
It is also possible that this evaluation may provide for inplant capacitors on the 4-kV system.
We will continue to keep you advised as to our evaluations of final modifications required to ensure minimum voltage levels.
Very truly yours, TE!iNESSEE VALLEY AUT!iORITY H. S. Fox Director of Power Production cc:
Director (3)
Office of Management Information and Program Control U.S. Nuclear Regulatory Commission Washington, D.C.
20555 Director (40)
Office of Inspection and Enforcement U.S. Nuclear Regulatory Consission Washington, D.C.
20555