ML20147E170
| ML20147E170 | |
| Person / Time | |
|---|---|
| Site: | Sequoyah  |
| Issue date: | 01/07/1988 |
| From: | NRC OFFICE OF SPECIAL PROJECTS |
| To: | |
| Shared Package | |
| ML20147E128 | List: |
| References | |
| NUDOCS 8801210031 | |
| Download: ML20147E170 (3) | |
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[gk& EICqo UNITED STATES fj ,s r I,j t NUCLEAR REGULATORY COMMISSION W ASHINGTON. D. C. 20555
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g%. . . . . f-SAFETY EVALUATION BY ThE OFFICE OF SPECIAL PROJECTS SUPPORTING Al4ENCHENT NO. 64 TO FACILITY OPERATING LICENSE h0 OPR-77 AND AMENDFENT N0. 56 TO FACILITY OPERATING LICENSE NO. DPP-79 TEFhESSEE VALLEY AUTHORITY SE0VOYAH NUCLEAR PLANT, UNITS 1 AhD 2 DOCKET NOS. 50-327 AND 50-328 1.0 IllTRODUCTION By letter dated August 11, 1987, the Tennessee Valley Authority (TVA) submitted proposed change 87-32 to the Tectnical Specifications of the Sequoyah Nuclear Plant Units 1 and 2. The proposed change would revise the loads at which the diesel generaters are tested during various porticos of the surveillance requirements in Section 4.8.1.1.2. These changes would be made te Le consis-tent with upwaro rt; visions of the continuous and short-time kilowatt ratires of the diesel generators necessitated by revised loading analyses. The proposed change also would modifv the nomenclature of the limits to be con-sistent with industry stancards '(IEEE 387-72).
2.0 DISCUSSION The Sequoyah FSAR and Technical Specifications identif continucus limit of 4000 kw (besed on .8 power factor)yand thethe diesci-generator short time limit (2 hcurs per day) at 110% of this value, 4400 kw. TVA rctes that, for the loads actually connected at Seouoyah, the power factors at which the diesel generators operate is censiderably higher. TVA tsserts that, for these higher power factors, the originally specified limits are unwarrantedly conservative.
To support this assertion TVA provided the diesel-generator original design specifications and drawings as well as additional anclyses performed by the manufacturer and by TVA. These analyses were originally submitted by letter dated February 27, 1987 (Enclosure 2 of the August 11, 1987 submittal).
The rated cutput of a diesel-gererator set is dependent on the power forter of the load to which it is connected. The overall diesel generater set capability ray be governed either by limits of the engine or of the generator, depending on the power factor.
880121o031 080107 i PDR ADDCK 05000327 P PDR
2 For power factors from 1.0 down to 0.88, the diesel generator set is engine limited; from 0.88 to 0.8, the set is generator limited. The ratings ir the Technical Specifications are the limiting ratings for a power factor of 0.8.
However, the conditions under which the diesel is normally tested, or runs with a loss of offsite power, are in the range where the diesel generatcr is engine limited. Therefore, TVA proposes that the diesels be testeo at ratings that correspond to a 0.88 power factor, that is, ecuivalent to 4400 kw ane 4840 kw.
The worst-case desion loading conditions for the diesel generator sets, based en revised calculations, would be within the tranufacturer's ratina for the engine (4400 kw continuous), but higher than the value specified in the Technical Specification surveillance (4000 kw) for the diesel generator sets.
Therefore, TVA proposed the Technical Specification change to trake the testing requirements more representative of the manufacturer's ratings and the leading requirements.
The proposed changes to Technical Specifications Section 4.8.1.1.2 are:
'Fevise the oiesel generator continuous rating from 4000 kw to 4400 kw.
' Revise the diesel generator two-hour rating from 4400 kw to 4840 kw.
' Revise the wording for Technical Specification 4.8.1.1.2.d.8 from "2000 neur rating" to "continuous rating."
The continuous rating is the level at which the diese' generators are tasted during the tronthly surveillance and the value used for ?? of the 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> of the run test conducted every 18 months. The 2-hour ratin; is applied fer the first 2 hours2.314815e-5 days <br />5.555556e-4 hours <br />3.306878e-6 weeks <br />7.61e-7 months <br /> of this test.
3.0 EVALUATION Tbc staff has reviewed the request for the Technical Specifications changes and has determined: (1) The generator is limited to 5000 kva on a continuous basis and 5500 kva (110%) for 2 hours2.314815e-5 days <br />5.555556e-4 hours <br />3.306878e-6 weeks <br />7.61e-7 months <br /> per day. At a power factor of 0.8, these limits are equivalent to 4000 kw and 4400 kw; however, at higher power factors, the generator is capable of higher kw loads within its original design envelepe; (2) The engine is limited to 6140 BHP on a continuous basis and 6754 BHP for 2 hours2.314815e-5 days <br />5.555556e-4 hours <br />3.306878e-6 weeks <br />7.61e-7 months <br /> per day. These limits are equivalent to 4397 kw and 4837 kw; (3) Certain other limits exist for the first 3 minutes of operation ano for momentary loadings but these are not relevant for operation in the modes called out in surveillance procedure.
Based on our review of the diesel generator loading calculations and load lists, the NRC stof f concurs with the TVA that, when operating indepenoently of offsite power, the diesel generators will operate at pcrer factors sufficiently high that the engine limit will be reached before the generator limit. Further, the staff firts that, during the paralleled operation called out in the surveillance procedure, the oiesel generator can be operated at sinilar higher power factors without underexciting the generator and, therefore, the engine limits are appropriately used as surveillance test
3 limits. The staff has also rtviewed Seouoyah System Operating Instruction (501) 82.1 (Revision 24) Diesel Generator, and finds the graphical display of limits in Appendix A-C to tse an appropriate and censistent means for operating the diesel generators within the specified limits during testing and normal operation. For these reasons, the staff concludes that the proposed Technical Specification changes are acceptable.
The wording change requested by TVA would provide consistency in terminology between the Technical Specifications requirements and IEEE Standard 387-1972, "Criteria for Diesel Generator (nits Applied as Standby Power Supplies for Nuclear Power Generating Stations." Therefore, the staff finds this change acceptable.
The staff notes that the diesel generator loading calculation (SON-ES-002, Revision 5), which the staff used to obtain operating power factors and loadings, asswes Unit 1 to be in cold shutdown. Therefore, prior to a resumption of power operation of Unit 1, a new analysis will be needed to confirm that the worst-case loading rerains within the manufacturer ratings and the surveillance reouirement limits discussed above for two-unit operation.
4.0 ENVIRONMENTAL CONSIDERATION
These amendments involve a chance to the surveillerce requirements. Tht. staff has determined that the amendments involve no significant increase in the amounts, and no significant change in the types, of sny effluerts that may be released offsite, and that there is no significant increase in individual or cumulative occupational radiation exposure. The Commissien has previously issued a propcsed finding that these arendments involve no significant ha:ards consideration and there has been no public cement on such finding.
Accordingly, the amendments meet the eligibility critoria for categorical exclusion set forth in 10 CFR 51.2?(c)(9). Pursuant to 10 CFR 51.22(b), no environmental impact statement nor environmental assessment need be prepared in connection with the issuance of the amendrents.
5.0 CONCLUSICN Ue have concluded, based on the considerations discussed above, that:
(1) there is reasonable assurance that the health and safety of the public will not be endangered by operation in the prvposed manner, and (21 such activities will be cenducted in compliance with the Commission's reculations, and the issuance of the acendments will not be ininical to the common defense and security nor to the health and safety of the public.
Principal Cor.tributor: E. Goodwin Dated: January 7,1938
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