ML15112A558
| ML15112A558 | |
| Person / Time | |
|---|---|
| Site: | Oconee  |
| Issue date: | 01/26/1998 |
| From: | Labarge D NRC (Affiliation Not Assigned) |
| To: | Mccollum W DUKE POWER CO. |
| References | |
| TAC-M93550, NUDOCS 9802040089 | |
| Download: ML15112A558 (5) | |
Text
Mr. William R. McCollurJanuary 26, 1998 Vicie President, Oconee n
Duke Energy Corporation P.tO. Box 1439 Seneca, SC 29679
SUBJECT:
REQUEST FOR ADDITIONAL INFORMATION RELATED TO DUKE ENERGY,,
CORPORATION RESPONSE TO THE NRR DRAFT REPORT ON THE OCONEE EMERGENCY POWER SYSTEM (TAC NO. M93550)
Dear Mr. McCollum:
By letter dated October 31, 1996, Duke Energy Corporation (formerly Duke Power Company) responded to the NRR Draft Report on the Oconee Emergency Power System dated July 8, 1996. As a result of our review of this information, we have determined that additional, information and clarification is needed to close out open issues and help finalize our report on the Oconee/Keowee emergency electrical distribution system. We request that you respond to the enclosed request for additional information within 30 days of receipt of this letter. This request replaces a request for additional information on the same subject dated January 22, 1998.
Sincerely, ORIGINAL SIGNED BY:
David E. LaBarge, Senior Project Manager Project Directorate 11-2 Division of Reactor Projects - 1/Il Office of Nuclear Reactor Regulation Docket Nos. 50-269, 50-270, and 50-287
Enclosure:
As stated cc w/encl: See next page DISTRIBUTION w/enclosure:
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RE UNITED STATES NUCLEAR REGULATORY COMMISSION WASHINGTON, D.C. 20555--001 January 26, 1998 Mr. William R. McCollum Vice President, Oconee Site Duke Energy Corporation P. 0. Box 1439 Seneca, SC 29679
SUBJECT:
REQUEST FOR ADDITIONAL INFORMATION RELATED TO DUKE ENERGY CORPORATION RESPONSE TO THE NRR DRAFT REPORT ON THE OCONEE EMERGENCY POWER SYSTEM (TAC NO. M93550)
Dear Mr. McCollum:
By letter dated October 31, 1996, Duke Energy Corporation (formerly Duke Power Company) responded to the NRR Draft Report on the Oconee Emergency Power System dated July 8, 1996. As a result of our review of this information, we have determined that additional information and clarification is needed to close out open issues and help finalize our report on the Oconee/Keowee emergency electrical distribution system. We request that you respond to the enclosed request for additional information within 30 days of receipt of this letter. This request replaces a request for additional information on the same subject dated January 22, 1998.
Sincerely, David E. LaBarge, Senior Project Manager Project Directorate 11-2 Division of Reactor Projects - 1/11 Office of Nuclear Reactor Regulation Docket Nos. 50-269, 50-270, and 50-287
Enclosure:
As stated cc w/encl: See next page
Oconee Nuclear Station cc:
Mr. Paul R. Newton Mr. J. E. Burchfield Legal Department (PBO5E)
Compliance Manager Duke Energy Corporation Duke Energy Corporation 422 South Church Street Oconee Nuclear Site Charlotte, North Carolina 28242 P. 0. Box 1439 Seneca, South Carolina 29679 J. Michael McGarry, Ill, Esquire Winston and Strawn Ms. Karen E. Long 1400 L Street, NW.
Assistant Attorney General Washington, DC 20005 North Carolina Department of Justice Mr. Robert B. Borsum P. O. Box 629 Framatome Technologies Raleigh, North Carolina 27602 Suite 525 1700 Rockville Pike L. A. Keller Rockville, Maryland 20852-1631 Manager - Nuclear Regulatory Licensing Manager, LIS Duke Energy Corporation NUS Corporation 526 South Church Street 2650 McCormick Drive, 3rd Floor Charlotte, North Carolina 28242-0001 Clearwater, Florida 34619-1035 Mr. Richard M. Fry, Director Senior Resident Inspector Division of Radiation Protection U. S. Nuclear Regulatory North Carolina Department of Commission Environment, Health, and 7812B Rochester Highway Natural Resources Seneca, South Carolina 29672 3825 Barrett Drive Raleigh, North Carolina 27609-7721 Regional Administrator, Region II U. S. Nuclear Regulatory Commission Atlanta Federal Center 61 Forsyth Street, S.W., Suite 23T85 Atlanta, Georgia 30303 Max Batavia, Chief Bureau of Radiological Health South Carolina Department of Health and Environmental Control 2600 Bull Street Columbia, South Carolina 29201 County Supervisor of Oconee County Walhalla, South Carolina 29621
REQUEST FOR ADDITIONAL INFORMATION DUKE ENERGY CORPORATION (DEC)
OCONEE NUCLEAR STATION ELECTRICAL DISTRIBUTION SYSTEM Quedtions 1 - 4 are follow-up to responses in DEC letter dated May 22, 1997:
- 1.
The response to question 2 indicates that, depending on the type of start and speed of the Keowee unit during the start, the gate limit is 0 percent, 25 percent, 50 percent, or 100 percent. It is not clear, however, what hardware establishes these limits. From other documentation the staff has seen, it appears that a partial shutdown solenoid and a gate limit motor set the limits. The partial shutdown solenoid appears to establish the 25 percent and 50 percent limits when the solenoid is respectively deenergized and energized. Does the gate limit motor set the other limits? Briefly describe how this, or other hardware, interfaces with the governor during the course of emergency and normal starts to change the gate limits.
- 2.
The response to question 2, Part 2b, states that the acceptance criteria for the Keowee monthly technical specification start test (PT/0/A/0620/09) is 57 to 63 Hz. This is
+/- 5 percent of the nominal frequency. Regulatory Guide 1.9 specifies a frequency of
+/- 2 percent. Why is +/- 2 percent not specified for the frequency in this surveillance? Are all the electrical equipment qualified for +/- 5 percent steady state frequency?
- 3.
The response to question 2, Part 2e, indicates that there are three emergency power switching logic tests, one for each Oconee unit; and of these, one test starts Keowee from a dead stop, while the other two tests start Keowee from grid generation. It is stated that the tests are all basically the same. Explain how all the tests are basically the same. If only a dead stop or grid generation start is performed on a particular unit, is the unit-specific switching logic tested in all modes, or is this logic independent of the initial condition of the Keowee units? Briefly explain.
It is also stated in the response that PT/1/A/0610/01J results in a black run of the associated Keowee unit instead of a black start. A black run of a Keowee unit does not result in a test of the Keowee field flash capability when the charger is unavailable and the dc system is only supported by the battery. It is also not clear if these tests challenge (test) the automatic transfer capability of the Keowee 1X and 2X switchgear in the manner they would be required to operate for various loss of offsite power scenarios that would require their operation. Discuss how the field flash and automatic transfer capabilities are routinely tested to demonstrate their required operation during various loss of offsite power scenarios.
- 4.
The response to question 9 states that the upper bound for the Keowee Air Circuit Breaker (ACB) reclosure timers is 23 seconds, which is consistent with the maximum required time for the Keowee units to be available to deliver emergency power. Should 23 seconds, therefore, be specified as the upper bound in the annual Keowee emergency start test?
-2
- 5.
In the NRR Draft Report, the staff was concerned that the demand frequencies of components such as relays, for which plant-specific data were calculated by combining all components of the same type into a type code, range from daily (for system grid generation) to quarterly to every refueling outage. Ideally, all components in the same group or type code should have the same or similar periodic testing frequencies. At Keowee, some components that are only challenged every refueling outage are applied the same failure probability as components that are demanded daily. Therefore, the staff concluded in the NRR Draft Report that the results of the generic data sensitivity study are more robust than the base case. In its response dated October 31, 1996, DEC agreed that for an ideal and precise characterization of the reliability of a component, the failure rate data should come from identical components with identical operating, service, testing, and maintenance conditions. DEC also stated that the generic data sources contain no statement of limitations for using the data for any specific test frequency or class of equipment. The staff believes that the purpose of gathering plant-specific data is to understand what kind of failures are contributing to the plant-specific failure data, how they occur, and when they occur. Analysis of plant specific data allows the analyst to determine whether a set of similar components of one type should be statistically modeled as one population.
In Table E3 of the Keowee Probabilistic Risk Assessment (PRA), DEC identified 12 components that are demanded during an emergency operation with a black start but not during normal operation and are tested less than every week, including ACBs 3-8.
DEC stated (in the October 31, 1996, submittal) that the Keowee PRA data base had been reviewed and only one failure of an infrequently test/demanded component was identified.
In the Augmented Inspection Team (AIT) report dated July 30, 1997, several ACB failures involving ACBs 7 and 8 (Section E.2.2.b.2 of the AIT report) were listed. The AIT concluded, based on its review of the historical data, that fuse and circuitry design interactions may have contributed to breaker failures.
The staff requests that DEC discuss this discrepancy. Since it appears that failure data for the X and Y relays for these ACBs were quantified using pooled data (as described in Tables C.1-3 and C.1-5), the staff requests that DEC requantify the applicable basic events for ACBs 5, 6, 7, and 8 using plant-specific data specific to the ACBs.