ML20043B030
| ML20043B030 | |
| Person / Time | |
|---|---|
| Site: | FitzPatrick  |
| Issue date: | 05/18/1990 |
| From: | Labarge D Office of Nuclear Reactor Regulation |
| To: | Brons J POWER AUTHORITY OF THE STATE OF NEW YORK (NEW YORK |
| References | |
| NUDOCS 9005240100 | |
| Download: ML20043B030 (2) | |
Text
t Dock,et No. 50-333 v'
May 18,1990 Mr. John C. Brons Executive Vice President - Nuclear Generation Power Authority of the State of New York 123 Main Street White Plains, New York 10601
Dear Mr. Brons:
SUBJECT:
RELIABILITY OF MANUAL BUS TRANSFERS BETWEEN ONSITE AND OFFSITE POWER SUPPLIES - JAMES A FITZPATRICK NUCLEAR POWERPLANT-(JAFNPP)
The Safety Evaluation. supporting Amendment 120 to Facility Operating License No. DPR-59 for JAFNPP, issued on November 18, 1988, expressed the staff's concern related to the onsite and offsite power sources.
Specifically, the staff indicated it believes that there are potential design weaknesses affecting the reliability of manual bus transfers between onsite and offsite power supplies. Manual transfers, in certain operating modes, result in undesirable power source (s) phase and voltage conditions which could result in damage to safety-related buses and electrical equipment.
Our concern was again expressed to your staff during our review of your January (UVR) 1990, amendment request relating to Degraded Voltage under-voltage 20 relay setpoints and the removal of the operating restrictions previously-imposed by Amendment 120. As the result of discussions relating to our concerns, we indicated that specific details of our concern would be 4
identified and provided to your staff for resolution. Enclosed are the details related to our concern.
Since the manual bus transfer concern was identified in November of 1988 and sufficient information has not been provided to the staff for resolution, we request that a meeting be scheduled to address the issue due to the potential impact on safety-related buses and electrical equipment.
Sincerely,
% 2. N k d*
cufcl David E. LaBarge, Project Manager Project Directorate I-1 Division of Reactor Projects - I/II Office of Nuclear Reactor Regulation i
Err.losure:
j As stated cc: See next page
- See previous concurrence l
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i ENCLOSURE I
OUTSTANDING.I$$UES. RELATING TQ.
' N ;.JAMFi.A..FITIPATRICK NUCLEAR P'JWER P. ANT PUWER SUPPLIES 1.
Motors rated at 575 Volts are powered from the 600V buses at the Fitzpatrick facility. Motors are usually rated for continuous service over a range of.90 pu to 1.10 p(u of their rated voltage.PPS),isat122kVthe600Vbusesare When the offsite Preferred Power System j
648V which is 1.13 pu. Neglecting any tolerance contributions, this i
exceeds the allowed 1.10 pu. Under some conditions e.g., when the motor load is less than rated, this excess could be-acceptable; however the licensee must provide justification to support the adequacy of the FitzPatrick design.
In addition, the basis to support that 122kV is the absolute maximum grid voltage is also required. No mention is made in the FSAR or Technical Specifications (TS) of overvoltage protection.
It appears that, in attempting to avoid transient low voltages, NYPA may be continuing the >ractice of allowing 1.13 pu as a potential steady state motor voltage wille attempting to minimize low voltage conditions in parts of the distribution system.
2.
During the past two years the NRC and NYPA have discussed the 25a phase shift between the Normal Power Supply (NPS) (i.e., the main generator and T4) and the PPS wbri the Main Generator is above some power level and near full power. This phase shift was reason for the request to eliminate the TS requirement to manually transfer one safety division to the PPS when the emergency diesel generator (EDG) associated with that safety division was inoperable. Provide details of all current operating
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conditions, including-testing and emergency conditions, which require manual transfer.
i 3.
Provide details of any long term corrective actions,.such as Automatic fast transfer, that is being considered to improve the overall system reliability.
4 Provide details on the coordination of the Fitzpatrick reactor operations' i
with the system load dispatchers, during all seasonal conditions, to assure that the PPS is adequate to provide power to the unit's safety-related buses and loads.
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