ML20129J787
| ML20129J787 | |
| Person / Time | |
|---|---|
| Site: | Maine Yankee |
| Issue date: | 07/18/1985 |
| From: | Whittier G Maine Yankee |
| To: | Butcher E Office of Nuclear Reactor Regulation |
| References | |
| 6040L-SEN, GDW-85-199, MN-85-134, NUDOCS 8507230343 | |
| Download: ML20129J787 (4) | |
Text
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EDISON DRIVE MAME HARHEE ATOMICPOWERCOMPARUe avausra. uanne orsas (207) 623-3521 July 18,1985 O
MN-85-134 GDW-85-199 Director of Nuclear Reactor Regulation United States Nuclear Regulatory Commission Washington, D. C.
20555 Attention:
Mr. Edward J. Butcher, Jr.
Acting Branch Chief Operating Reactors Branch No. 3 Division of Licensing
References:
(a) License No. OPR-36 (Docket No. 50-309)
(b) USNRC Letter to MYAPCo, dated June 8,1983 (c) MYAPCo Letter to USNRC, dated December 19, 1983 (MN-83-249)
(d) USNRC Letter to MVAPCo, dated May 25, 1984 (e) MYAPCo Letter to USNRC, dated October 11,1984 (MN-84-176)
(f) MYAPCo Letter to USNRC, dated October 29, 1984 (MN-84-175)
(g) USNRC Letter to MYAPCo, dated March 20, 1985
Subject:
Maine Yankee Offsite Power Supplies Gentlemen:
At a meeting held on May 8,1985, between representatives of Maine Yankee and the staff, the open items contained in Reference (g) were discussed.
The purpose of this letter is to document the results of that meeting.
NRC Open Item Based on our review of the APSV study and your letters dated October 11 and October 29, 1984 we find that you have:
(a) No plans to demonstrate the actual capacity of these lines at the refueling outage.
Maine Yankee Resolution In accordance with the staff's recommendation, Maine Yankee will perform the following test during each refueling outage. Maine Yankee will power the plant auxiliary loads from only the Surowelc 115 kV line and measure the Maine Yankee 115 kV switchyard voltage using installed instrumentation.
1.
Maine Yankee will develop a testing procedure by August 30, 1985.
Testing will be completed prior to start up after the 1985 refueling outage.
8507230343 850718 gDR ADOCK 0500 9
0d 6040L-SEN
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M AINE YANKEE ATOMIC POWER COMPAP$Y a
United States Nuclear Regulatory Commission Page Two Attention: Mr. Edward J. Butcher, Jr.
MN-85-134 NRC Open Item (b) Provided no data to validate your APSV study.
Maine Yankee Resolution Validation of the load flow program and model used for the APSV study will be provided in two parts for simplicity. The first part addresses the on-site portion of the computer model and the second part addresses the off-site portion of the computer model.
o On-Site Computer Model Yankee Atomic Electric Company Report #YAEC-1204, the predecessor of the APSV 7tudy provided the staff with two validations of the load flow program and the on-site portion of the computer model. A copy of the validation data contained in YAEC-1204 (Table 5.1) is provided as an enclosure to this letter.
The YAEC-1204 validations consisted of recording auxiliary power system data while the plant was operating and then using that data with the load flow program and the on-site computer model to predict specific bus voltages. The enclosed results (Table 5.1) show that the deviations between the actual and predicted bus voltages are minimal.
Off-Site Computer Model o
Validation of the off-site portion of the computer model has been achieved through data provided by the Voltage Schedules and Reactive Dispatch Task Force (VSROTF) of the New England Power Exchange (FEPEX).
NEPEX, the control center of the New England Power Pool (NEP00L), is responsible for reliable and economic operation of NEP00L generation and transmission facilities.
The VSRDTF is charged with the responsibility of ensuring that adequate voltage is available at all nuclear power plants in the New England area. Consequently comprehensive analyses have been performed to determine the minimu,m Maine Yankee switchyard voltage for " worst case" conditions.
The results of these analyses predict a Maine Yankee l
switchyard voltage of 110.6 kV when the Mason 115 kV line is out of service and the maximum auxiliary power system load is transferred to the Suroweic 115 kV line alone. The minimum Maine Yankee switchyard voltage calculated by the APSV study is 110.0 for the same plant conditions.
It is clear from this data that the APSV results are valid. Although the APSV study results have been validated, Maine Yankee plans to use the VSRDTF data for future APSV studies because it is considered extremely accurate, more comprehensive and it is continually updated.
6040L-SEN
MAINE YANKEE ATOMIC POWER COMPANY 6
s United States Nuclear Regulatory Commission Page Three Attention:
Mr. Edward J. Butcher, Jr.
MN-85-134 Maine Yankee plans to update our computer models as needed to reflect plant and distribution system changes once per cycle.
2.
Accordingly, by August 30, 1985, Maine Yankee will implement a program for review and updating, as appropriate, of our voltage system computer models.
The purpose.of this program is to periodically verify the adequacy of Maine Yankee's station service power systems.
NRC Open Item (c) Accomplished only 2.5% of the proposed 5% tap settings on the reserve service transformer (X-14) during recent refueling due to misinterpretation of the service order.
Maine Yankee Resolution 3.
Maine Yankee will complete the tap setting change during the 1985 refueling outage.
Until that time, the interim auxiliary power system precaution provided to the plant operators will remain in effect to compensate for the incomplete tap change.
Very truly yours, MINE YANKEE ATOMIC POWER COWANY c
bh AV-G. D. Whittier, Manager Nuclear Engineering & Licensing GDW/bjp Enclosure cc: Dr. Thomas E. Murley Mr. Cornelius F. Holden l
6040L-SEN
r Table 5.1 Predicted Voltage Vs. Measured Voltage Verification #1 - December 6, 1979 - 0400 hours0.00463 days <br />0.111 hours <br />6.613757e-4 weeks <br />1.522e-4 months <br /> Predicted Voltage Measured Voltage Percent Deviation Bus (Volts)
(Volts)
(Percent) 6900 volt bus 1 6762 6800
.56 6900 volt bus 2 6762 6800
.56 4160 volt bus 3 4147 4250
-2.42 4160 vol; bus 4 4147 4300
-3.56 4160 volt bus 5 4147 4200
-1.26 4160 volt bus 6 4147 4250
-2.42 480 volt bus 7 470 467
+.64 480 volt bus 8 471 466
+1.07 Verification 21 - December 8, 1979 - 1200 hours0.0139 days <br />0.333 hours <br />0.00198 weeks <br />4.566e-4 months <br /> Predicted Voltage Measured Voltage Percent Deviation Bus (Volts)
(Volts)
(Percent) 6900 volt bus 1 6731 6800
-1.01 6900 volt bus 2 6731 6800
-1.01 4160 volt bus 3 4131 4230
-2.34 4160 volt bus 4 4131 4280
-3.48 4160 volt bus 5 4131 4200
-1.64 4160 volt bus 6 4131
-1.64 480 volt bus 7 468 462
+1.30 480 volt bus 8 468 466
+.43 620ll-SEN
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