ML20198D316
| ML20198D316 | |
| Person / Time | |
|---|---|
| Site: | Arkansas Nuclear  |
| Issue date: | 05/05/1992 |
| From: | Peterson S Office of Nuclear Reactor Regulation |
| To: | Carns N ENTERGY OPERATIONS, INC. |
| References | |
| TAC-M82164, TAC-M82165, NUDOCS 9205200111 | |
| Download: ML20198D316 (7) | |
Text
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May 5, 1992 kcket Nos. 50-313 and 50-368 Mr. Neil S. Carns Vice President, Operations ANO Entergy Operations, Inc.
Route 3 Box 137G Russellville, Arkansas 72801
Dear Mr. Carns:
SUBJECT:
REQUEST FOR ADDITIONAL INFORMATION REGARDING OFFSITE POWER SUPPLIES FOR ARKnNSAS NUCLEAR ONE, UNITS 1 and 2 (AfM-l&2)
(TAC NOS. M82164 ANC M82165) g c>
y
. le staff nas reviewed yuur letter dated April 8,1992, and Licensee Event X
"eport (50-313/91-010-01) dated March 27, 1992, regarding the adequacy of the 161 KV of fsite power scurce for ANO-l&2 during summer load conditions.
The information requested in the enclosure is required sa that the staff can
- cmplete its review and determine if the requirements of Generai Desios Criterion 5 will be mei.
The reporting requirements contained in this letter affect fewer than J.
ten respondents; therefore. Of' ice of Management and Budget clearance is not required ur >
Public Law 96-511.
We reauest your response to the questions within 20 days of receipt of this letter to enable the staff to complete its review in a timely manner.
Sincerely, Original signed by Thomas W. Alexion for:
Sheri R. Petersnn, Project Manager Project Directorate IV-1 Division of Peactor Projects - III/IV/V Office of Nuclear Reactor Regulation Original signed ;:
Thomas W. Alexion, Project Manager Project Directorate IV-1 Division of Reactor Projects - III/IV/V Office of Nuclear Reactor Regulation Enchsure:
Request for Additional Information 2 W he ex pa DISTRIBUTI0h.
Docket File NRC & Local PDRs PD4-1 Reading JLarki-BBoger MVirgiiio SLittle RJer. ' is 000 ACRS (10)
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o May 5, 1992 Docket Nos. 50-313 and 50-368 Mr. Neil S. Carns Vice President, Operations ANO Entergy Operations, Inc.
Route 3 Box 137G Russellville, Arkansas 72801
Dear Mr. Carns:
REQUEST FOR ADDITIONAL INFORMATION REGARDING OFFSITE POWER
SUBJECT:
SUPPLIES FOR ARKANSAS NUCLEAR ONE, UNITS I and 2 (ANO-l&2)
(TAC N0f. MS2164 AND MS2165)
The staff has reviewed your letter dated April 8, 1992, auj Licensee Ever.t dated M rch 27, 1992, regarding the adequacy of the Report (50-313/91-010-01) 161 KV offsite power source for ANO-l&2 during summer load conditions.
The information requested in the enclosure is required so that the staff can complete its review and determine if the requirements of General Design Criterion 5 will be met.
The reporting requirements contained in this letter affect fewer than ten respondents, therefore, Office of Management and Budget cl2arance is not required under Public Law 96-511.
We request your response to the questions within 30 days of receipt of this letter to enable the staff to complete its review in a timely manner.
Sincerel,
n, Projet I
s %)
. Alexio Manager Thomas Project Directorate IV-1 Division of Reactor Projects - III/IV/V Office of belear Reactor Regulation r
^
f Sheri R. & son,)Pr LWh.)
Peter et Manager
[A J roject Directorate IV-I Division of Reactor Projects - III/IV/V Office of Nuclear Reactor Regulation
Enclosure:
Request for Additional Information cc w/ enclosure:
See next page
_ _ _ _ _ _ ~ ~ - - '
n Mr. Neil S. Carns Entergy Operations, Inc.
Arkansas Nuclear one, Units 1 & 2 cc:
Mr. Donald C. Hintz Mr. John R. McGaha Executive Vice President Vice President, Operations Support and Chief Operating Officer Entergy Operations, Inc.
Entergy Operations, Inc.
P. O. E 31995 P. v. Box-31995
- Jackson, ississippi 39286 Jackson, Mississippi 39286 Mr. Robert B. McGehee Mr. Jerry Yelverton Wise, Carter, Child & Caraway Gene n1 Manager, Plant Operations P. O. Box 651 Entergy Operations, Inc.
Jackson, Mississippi 39205
' Route 3 Box 137G Russellville,-Arkansas 72801 Mr. Charles B. Brinkman, Manager Washington Nuclear Operations Mr. Nicholas S. Reynolds ABB Combustion Engineering Nuclear Power Winston & Strawn 12300 Twinbrook Parkway, Suite 330 1400 L Street,.N.W.-
Rockville, Maryland 20852 Washington, D.C.
20005-3502 Mr. James J. Fisicaro Mr. Robert B. Borsum Director, Licensing Licensing Represe:itative Entergy Operations, Inc.
B&W Nuclear Technologies Route 3, Box 137G 1700 Rockville Pike, Suite 525 Russellville, Arkansas 72801 Rockville, Maryland 20852 Admiral Kinnaird R. McKee, USN (Ret)
Senior Resident inspector 214 South Morris Street U.S. Nuclear Regulatory Comm' sion Oxford, Maryland 21654 1 Nuclear Plant Road Russellville, Arkansas 72801 Regional Administrator, Region IV U.S. Nuclear Regulatory Commission 611 Ryan Plaza Drive, Suite 1000 Arlington, Texas 76011 Honorable Joe W. Phillips County Judge of Pope County Pope County Courthouse Russellville, Arkansas 72801 Ms. Greta Dicus, Director Division of Radiation Control and Emergency Management Arkansas Department of Health 4815 West Markham Street Little Rock, Arkansas 72205-3867
a v
Enclosure RE0 VEST FOR ADDITIONAL INFORMATION OFFSITE POWER SOURCLS FOR ARKANSAS NUCLEAR ONE. UNITS 1 and 2 (ANO-I&E)
[NI[RGY 3PERATIONS. INC.
DOCKET NOS. 50-313 and 50-368
1.0 INTRODUCTION
On October 5, 1991, an Arkansas Nuclear One (ANO) engineering evaluation identified specific conditions that could render the second source of offsite power, the 161 KV system, unable to supply adequate voltage to engineered safety feature (ESF) loads.
The licensee had determined that during peak summer load conditions the 161 KV offsite power source (5tartup Transformer 2) might not be abic to supply adequate voltage to ANO loads during accident conditions with both units off line and the immediate access.offsite power source (500/161 auto transformer) unavailable. The licensee attributes the
. cause of the deficiency to a load growth that was not identified because of a failure to incorporate the Millstone Degraded Grid Voltage requirements into the Entergy transmission system review criteria.
The licensee estimates that the loading will exceed the analyzed condition in the summer of 1992. The licensee has implemented short-term corrective actions (C/As) and-proposed long-term corrective actions to ensure that adequate voltage can be provided from the 161 KV system under the higher lead conditions.
2.0 EVALVATION By letter dated April 8, 1992, Entergy Operations submitted a report describing-its long-term plan to ensure that the 161 KV offsite power source will meet the requirements of General Design Criterion (GDC) 17 of Appendix A L
'of 10 CFR Part 50 for ANO-l&2 during summer load conditions. The licensee's submittal and the supplement to the Licensee Event Report (50-313/91-010-01) dated March 27,1992,' on this subject list the following C/As to enable full-i power operation from 1992 through 1996 during projected peak (summer) load conditions:
i
_ Voltage tap changes to increase the voltage on the 480 VAC safety L
buses were completed on the 4160/480 VAC load center transformers serving the IE safety-related loads. The tap changes for ANO-2 were completed on March 10, 1992. Those for ANO-1 were completed l
during the IR10 refueling outage-(completed April 1992).
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i A 161 KV transmission capacitor bank will be installed at the ANO
=
switchyard by May 1, 1992.
This capacitor bank is planned to be used in conjunction with administrative procedures fer load shedding actions by the transmission system dispatcher.
Additional transformer taps at the Mayflower substation auto transformer will be changed as necessary.
Since these tap changes may cause overvoltage conditions, the licensee will ensure that a reactor bank at the Mayflower substation is installed as scheduled with the other planned actions. These actions will be performed by May 1, 1992.
The licensee has implemented procedural and operational guidance changes to prevent t icceptable voltages when the auxiliary loads are transferred to Stortup Transformer #2 (S/U-2). These changes require that the control switches for the feeder breakers from S/U-2 to both units be maintained in the " Pull to Lock" position except under carefully analyzed conditions.
This position disables the auto transfer of the auxiliary loads to S/U-2 and allows selective manual loading of the transformer.
At the Entergy Dispatching Center, operating procedures have been established that provide guidance for restoration of the 161 KV offsite voltage levels at ANO.
In addition to the thesc steps, the licensee has committed to perform an engineering reevaluation of the offsite voltage levels every 2 years to ensure that transmission area load growth will not again result in inadeouate offsite voltage levels.
The licensee estimates that the 1992 summer peak load for the Entergy System will be 11955 MW.
The projected annual load growth for the Entergy System is approximately 1.5% per year for tne next 10 years. The 1992 summer peak load level estimate is approximately 20% over the 1978 peak load level used in the initial Millstone Analysis to determine the adequacy of the offsite transmission system.
The licensee stated in the March 13, 1979, letter to NRR that the Millstone Degraded Grid Voltage Study-(MPA B-23) wa: based on the following initial conditions:
AUTO TRANSFORMER (500KV) IS OUT TIE BETWEEN 500 KV AND 161 KV SYSTEMS IS OUT MINIMUM VOLTAGE ON 161 KV SYSTEM 0F 1.0 P.U.
161 KV SYSTEM IS INTACT l
i Contrary to these original assumptions for the MPA B-23 Analysis, the long-term _ plan requires the intervention of the transmission system dispatcher to conduct load shedding actions to maintain acceptable voltages to S/U-2.
1 Further, the maximum MW/MVAR load level that can be maintained nomincily lf' without action by non-licensed personnel is not clear from the licensee's submittal.
Therefore, the proposed actions are at best an interim solution.
In addition, if the current load growth projections underestimate future peak loading, the licensee proposes to take credit for a hydrogenerating unit as a means to maintain adequate voltage on the 161 KV system. This position is contrary to the intent of GDC 5 and GDC 17.
Therefore, based on a review of the proposed long-term plan as outlined above, the staff concludes that the results of the C/As are not distinctive and sufficient for long-term resolution of this issue.
3.0 ADDIT 10t{Al. INFORMATION RE0VIRED The licensee's short-term actions appear to have returned the 161 KV system to compliance with GDC 17.
However, statements by the licensee for the longer term imply that, if load growth projections are underestimated, dispatcher actions will be used to maintain adequate voltage on tM 161 KV system and credit will be taken for a hydrogenerating unit.
This position is contrary to the intent of GDC 5 and GDC 17.
The staff recognizes that transrission systam dispatcher actions and load reductions / additions are necessary during abnormal or emergency conditions on the grid.
external resources is not part of the licensing basis for ANO.However, the credit for or relianc Therefore, the long-term plan as currently proposed by the licensee is not acceptable for final resolution of this issue.
Based on the above review. the staff has concluded that additional information is needed.
To ascertain the adequacy of the proposed C/As to meet the 1992 summer peak load conditions, the licensee should, 1.
Provide the study supporting the licensee's conclusion that, as a result of the corrective actions planned, the 161 KV system will meet the reonirements of GDC 17 and GDC 5; 2.
Discuss specific operational requirements to prevent overvoltage or undervoltage conditions at ANO during extreme variations in transmission voltage and load conditions; 3.
Discuss the results of transmission model validation effort based on tctual test measurements taken when the 500/161 KV auto tr'ansformer was isolated from the 161 KV system and identify the degree of correlation between the transmission model projections and the measured test data; and b
4 4.
Provide a summary of the surveillance procedure implementing ANO-2 Technical Specification 4.8.1.1.1.a. which specifies that
" indicated power availability" of each offsite power source be verified to determine operability.
Given that the 500/161 KV bus tie auto transformer connecting the 500 KV and 161 KV switchyard has masked the inadequacy of the 161 KV system to provide sufficient voltage level (1.0 p.u. minimum) to safety loads during peak load conditions, what additional assurances can you provide to detect potential voltage inadequacies in the future?
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