ML19317D201
| ML19317D201 | |
| Person / Time | |
|---|---|
| Site: | Oconee  |
| Issue date: | 09/29/1977 |
| From: | Parker W DUKE POWER CO. |
| To: | Case E, Schwencer A Office of Nuclear Reactor Regulation |
| Shared Package | |
| ML19317D202 | List: |
| References | |
| NUDOCS 7911190595 | |
| Download: ML19317D201 (5) | |
Text
w U.S. NUCLEAR REGULATQ AY COMM*
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NRC DISTRIBUTION pon PART 50 DOCKET MATERIAL rO:
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E G Case Duke Power Company 9_yy Charlotte, NC CATE RECEIVED W 0 Parker JR 10-3-77 d LETTE n ENoTomizE o PacP iNPuTPonM NUM8ER OF CCPIES RECEIVED domQiNAL
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- ESCMIPTicN ENCLCSU ME notarized 9-29-77......trans the following:
Licnese # UPR-38, 47, C 55 Amend:
proposed chant e to tech specs concerning increased flexibility of operation C maintenance of electrical system 4P including the keowee hydroelectric station......
11p DISTRIBUTION OF MATERIAL CONCERNING ONSITE EMERGENCY POWER SYSTEMS PLANT NAME:
Oconee 1-3 10-%77 abf h (f 4.
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s DUKE power COMPANY Powra Burunxo 422 SocTn Cuuncu STazzT, Cn.ARWTTE, N. C. 20242
...uau o. PA R M E R. J R, September 29, 1977 bCt Poggioggt fgtgewomg: Ang^ 704 Sgt.u Peoovenon
?'v4te3 Mr. Edson G. Case, Acting Director Office of Nuclear Reactor Regulation U. S. Nuclear Regulatory Commission Washington, D. C. 20555 f
-r- ~'ss Attention:
Mr. A. Schwencer, Chief Operating React)rs Branch #1
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RE: Oconee Nuclear Station i
Docket Nos. 50-269, -270, -287
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Dear Mr. Case:
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In my letter of October 13, 1976, revisions to the Oconee Nuclear Station Technical Specifications were requested to provide increased flexibility of operation and maintenance of the Oconee electrical system including the I
Keowee Hydroelectric Station. Diesussions with your staff have identified the need for certain changes to this submittal.
The attached change pages incorporate these revisions. They are submitted as a proposed revision to the Oconee Nuclear Station Technical Specifications pursuant to 10CFR50, 550.90.
Discussions with the staff have also indicated the need for a general up-grading of the specifications relating to the operations of the Oconee batteries.
These revisions will be submitted by January 1,1978.
The onsite power system at Oconee Nuclear Station is provided by two 87.5 MVA hydroelectric generators (Keowee Hydro Station) supplying pcwer through two separate, diverse transmission paths.
Additionally, two gas turbines located at the Lee Steam Station and an isolated 100 kV transmission path provide a substitute onsite power source, primarily in instances when the hydro units are not available due to maintenance or testing.
Operation with one Keowee hydro Unit out of service for periods not to ex-l ceed 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br /> or operation with the underground feeder out of service for periods not to exceed 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br /> is requested.
Each of these situations is analogous to the operation of a plant with one diesel inoperable.
As an additional feature, when one Keowee hydro unit is inoperable, the remaining unit will be connected to the underground feeder circuit and will be verified operable within one hour of the loss and every eight hours thereafter by l
energizing the standby buses through the underground feeder circuit.
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Mr. Edson G. Casa j
,j Pegs.Two September 29, 1977 Operation with one Keowee hydro unit out of service from 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br /> up to a maximum of 45 days is also requested. The remaining Keowee unit and both the overhead and underground transmission circuits will be operable at this time and the standby buses will be energized by one of the two Lee gas turbines through the isolated 100 kV transmission circuit. This arrange-ment provides a high degree of reliability and the assurance of the availability of one emergency power source since it is in continuous operation.
The second Keowee hydro unit will be connected to the underground circuit and will be also available to the ove.+ head transmission line, a second independent path, to supply power to Oconee. A comparable condition is not normally designed at other stations nor addressed by current regulatory guidance. The Oconee SER and Technical Specifications state that expected outages for both Keowee units are one day per year and 4 days per ten years. No statement has been made for single Keowee unit maintenance outages. Single unit outages longer than the l
72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br /> are necessary periodically to perform major maintenance.
The primary long term maintenance items are expected to be the hydro turbine runner and i
discharge ring welding repairs which are estimated to be necessary approxi-mately every six to eight years and to require 6 weeks for repairs.
- Also, i
generatar thrust and guide bearings will require replacement approximately every 6 to 8 years with a maintenance period of 6 weeks. These two items can be performed concurrently. Although the potential exists for other maintenance items, these are the only two long term maintenance items which can be planned. Other items which manifest as failures are expected to be ex-tremely rare and could possibly be resolved during the proposed maintenance periods without the need for special licensing actions. Operation under this specification is to be restricted to periods not to exceed 45 days. These provisions could be utilized without prior NRC approval only once in three years per Keowee unit, however, the regional office of the NRC will be notified of operation of Keowee under this specification within 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> after the end of the initial 72 hour8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br /> maintenance period.
Operation with both Keowee hydro units out of service for either planned or unplanned reasons, for 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br /> and 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> respectively, is also requested.
Current regulatory guidance permits removal of both emergency power se trees for two hours but no backup emergency power source is provided. At Oconee, one of tha Lee gas turbines would be in operation energizing the standby buses j
through the 100 kV transmission circuit. Assurance of one emergency power l
source is thus provided. Due to the common penstock of the Keowee units j
maintenance on one Keowee hydro unit may require removing both hydro units from service simultaneously for periods of 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br />.
The envisioned plan for removal of one Keowee hydro unit from service for an extended period of time is:
Keowee head and tailgates would be lowered isolating both Keowee units.
i a.
b.
The hydro units and penstock would be pumped down.
Locking devices would be installed on the wicket gate arms to prevent l
c.
motion.
d.
The wicket gates on the Keowee unit to be recoved from service would be i
sealed.
4
Mr. Ed:on G. C :2 P ge Thres September 29, 1977 e.
The penstock area would be rewatered.
f.
The inoperable Keowee unit is checked for leaks.
g.
The head and tailgates are raised and the operability of the remaining Keowee unit is verified.
A period of 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br /> is considered necessary to properly perform this procedure.
This period of time is acceptable since a Lee gas turbine is in operation and hence its availability is assured.
In the unlikely eyent that a loss of all off-site power should occur in conjunction with the loss of the Lee gas turbine during a planned Keowee outage, both Keowee units could be restored to service in considerably less than 20 hours2.314815e-4 days <br />0.00556 hours <br />3.306878e-5 weeks <br />7.61e-6 months <br />. This is the minimum time that the steam driven emergency feedwater pump could be used for decay heat cooling as analyzed in section 14.1.2.8 of the FSAR.
It is not considered that the original service periods of one day per year and 4 days in 10 years are significantly altered by this procedure.
Indeed, the periods experienced to date with both Keowee units inoperable have been small and largely related to measurement of hydro leakage flow required by technical specifications.
A time period of'24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> for un-planned outages is considered acceptable since the operation of one of the two Lee gas turbines is assured within 1 hour1.157407e-5 days <br />2.777778e-4 hours <br />1.653439e-6 weeks <br />3.805e-7 months <br />.
This period of time will permit a deliberate investigation of the cause for the unplanned outage.
In addition to the two Lee gas turbines available on the loss of both Keowee hydro units, there are several other sources of power available, including six 230 kV transmission lines and two 500 kV transmission lines feeding into their respective switchyards at the Oconee site.
Your prompt consideration of this request is anticipated.
Ve /y truly yoursi j
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William O. Parker, Jr()
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Attachment l
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Mr. Edson G. Ctre O
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Pcgs Four September 29, 1977 WILLIAM 0. PARKER, JR., being duly sworn, states that he is Vice President of Duke Power Company; that he is authorized on the part of said Company to sign and file with the Nuclear Regulatoru Smmission this request for amendment of the Oconee Nuclear Station Technical Specifications, Appendix A to Facility Operating Licenses DPR-38, DPR-47 and DPR-55; and that all statements and matters set forth therein are true and correct to the best of his knowledge.
, O rr. _ O. G t-L. - n '
' William O. Parker, Jr., Vig President ATTEST:
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Subscr' bed and sworn to before me this 29th day of September, 1977.
Luk Vivian B. Robbins Nctary Public My Commission Expires:
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