ML20217N347
| ML20217N347 | |
| Person / Time | |
|---|---|
| Site: | Vogtle  |
| Issue date: | 10/25/1999 |
| From: | NRC (Affiliation Not Assigned) |
| To: | |
| Shared Package | |
| ML20217N344 | List: |
| References | |
| NUDOCS 9910280190 | |
| Download: ML20217N347 (3) | |
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UNITED STATES g
.I [qj NUCLEAR REGULATORY COMMISSION
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t WASHINGTON. D.C. 2055H001
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o SAFETY EVALUATION BY THE OFFICE OF NUCLEAR REACTOR REGULATION RELATED TO AMENDMENT NO. 109 TO FACILITY OPERATING LICENSE NPF-68 AND AMENDMENT NO. 87 TO FACILITY OPERATING LICENSE NPF-81 SOUTHERN NUCLEAR OPERATING COMPANY. INC.. ET AL.
VOGTLE ELECTRIC GENERATING PLANT. UNITS 1 AND 2 DOCKET NOS. 50-424 AND 50-425
1.0 INTRODUCTION
By letter dated May 18,1999, as supplemented by letter dated September 22,1999, Southern Nuclear Operating Company, Inc., et al. (SNC/the licensee) proposed license amendments to change the Technical Specifications (TS) for the Vogtle Electric Generating Plant (Vogtle),
Units 1 and 2.
The proposed changes would revise Surveillance Requirements (SR) 3.8.1.3 and 3.8.1.13 to mduce the loading requirements for the emergency diesel generators (EDGs). Revised SR 3.8.1.3 requires that the EDGs be loaded and operated for 260 minutes at a load 26500 kW and s7000 kW at least every 31 days. The revised SR 3.8.1.13 requires that the EDGs be loaded 26900kW and s7700 kW and operated as close as practicable to 3390 kVA for 2 hours2.314815e-5 days <br />5.555556e-4 hours <br />3.306878e-6 weeks <br />7.61e-7 months <br />.
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For the remaining hours of the test, the EDGs would be loaded 26500 kW and s7000 kW and i
operated as close as practicable to 3390 kVA. Changes to the associated Bases Section are also included.
The supplemental letter dated September 22,1999, provided clarifying information that did not change the scope of the May 18,1999, application and the initial proposed no significant hazards consideration determination. The September 22,1999, letter specifically proposed to include an upper limit of 7700 kW for the DG loading for the 2 hour2.314815e-5 days <br />5.555556e-4 hours <br />3.306878e-6 weeks <br />7.61e-7 months <br /> portion of SR 3.8.1.13. It also provided an updated calculated value for the maximum expected DG loading. This value is 6447 kW and 3248 kVAR, or 7216 kVA at 0.893 power factor.
2.0 EVALUATION The current surveillance requirements were based on Regulatory Guide (RG) 1.108, Revision 1, " Periodic Testing of Diesel Generator Units Used as Onsite Electric Power Systems at Nuclear Power Plants." Regulatory position C.2.a.(3) of RG 1.108 calls for demonstrating full-load carrying capability for an interval of not less than 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br />, of which 22 hours2.546296e-4 days <br />0.00611 hours <br />3.637566e-5 weeks <br />8.371e-6 months <br /> should be l
at a load equivalent to the continuous rating of the EDG and 2 hours2.314815e-5 days <br />5.555556e-4 hours <br />3.306878e-6 weeks <br />7.61e-7 months <br /> should be at a load equivalent to the 2-hour rat;ng of the EDG. The EDGs at Vogtle are rated at 7000 kW for continuous operation and 7700 kW for a short-term period (2 hours2.314815e-5 days <br />5.555556e-4 hours <br />3.306878e-6 weeks <br />7.61e-7 months <br />). Therefore, consistent with Regulatory Position C.2.a.(3), existing SR 3.8.1.13 requires, at least every 18 months, each EDG to be operated at a load between 7600 kW and 7700 kW for at least the first 2 hours2.314815e-5 days <br />5.555556e-4 hours <br />3.306878e-6 weeks <br />7.61e-7 months <br /> of the test and between 6800 kW and 7000 kW for the remainder of the 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br />.
9910280190 971025 PDR ADOCK 05000424 P
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. Subsequently, guidance from RG 1.108 was integrated into RG 1.9, Rev. 3. Item 2.2.2,
" Load-Run Test," of RG 1.9 calls for demonstrating 90 to 100 percent of the continuous rating of the EDG for an interval of not less than 1 hour1.157407e-5 days <br />2.777778e-4 hours <br />1.653439e-6 weeks <br />3.805e-7 months <br />. Item 2.2.9, " Endurance and Margin Test,"
calls for demonstrating full-load capability at a power factor between 0.8 and 0.9 for an interval of not less than 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br />, of which 2 hours2.314815e-5 days <br />5.555556e-4 hours <br />3.306878e-6 weeks <br />7.61e-7 months <br /> are at a load equal to 105 to 110 percent rating of
' the continuous rating of the EDG and 22 hours2.546296e-4 days <br />0.00611 hours <br />3.637566e-5 weeks <br />8.371e-6 months <br /> are at a load equal to 90 to 100 percent of its continuous rating.
The worst case scenario for EDG loading at most nuclear power plants is to assume a loss of offsite power in conjunction with a loss-of-coolant accident (LOCA). The worst case scenario for Vogtle is a loss of offsite power without a LOCA. This is due to the fact that during a loss of offsite power, the non-1E busses that provide power to the pressurizer heaters are initially shed from the 1E buses and then automatically sequenced back onto 1E buses. On a safety injection signal, these non-1E buses are not automatically loaded onto 1E buses. The maximum expected EDG loading under the worst case scenario for Vogtle was determined to be 6447 kW and 3248 kVAR, or 7216 kVA at 0.893 power factor. Therefore, the licensee chose to test the EDGs on a monthly basis loaded at 26500 kW and s7000 kW. This load band is consistent with the recommendations of RG 1.9, item 2.2.2, that '; alls for monthly testing a loads 90 to 100 percent of the continuous rating. For the Vogtle EDGs, this would corresp-
- to a load band of 6300 kW to 7000 kW. Therefore, the proposed change to the i
load bt for SR 3.8.1.3 bounds the maximum expected load, is consistent with the guidance of RG 1.v, Revision 3, and is, acceptable.
Item 2.2.9 of RG 1.9, Revision 3 calls for testing for 2 hours2.314815e-5 days <br />5.555556e-4 hours <br />3.306878e-6 weeks <br />7.61e-7 months <br /> at loads of 105 to 110 percent of the continuous duty rating for the EDG. For Vogtle, this would correspond to 7350 kW to 7700 kW. The licensee states that the EDG is capable of maintaining loads in the range of 7600 kW to 7700 kW for 2 hours2.314815e-5 days <br />5.555556e-4 hours <br />3.306878e-6 weeks <br />7.61e-7 months <br />. Some instances of increased cylinder head and turbocharger wear and lear have occurred and were attributed, by the vendor, to operating the EDG at these loads. The vendor has recommended that the licensee should reduce loading requirements for the 2-hour short-time rating of the EDG. Therefore, the licensee is proposing to operate the EDGs for 22 hours2.546296e-4 days <br />0.00611 hours <br />3.637566e-5 weeks <br />8.371e-6 months <br /> at loads that are equivalent to or greater than 105 percent of the maximum expected load in the worst case scenario (i.e.,105 percent of 6500 kW = 6900 kW) rather than the continuous rating of the EDG (i.e.,105 percent of 7000 kW = 7350 kW). This would represent an exception to the originallicensing basis of RG 1.108 and its replacement, RG 1.9, Revision 3. However, it would continue to c%monstrate an Adequate Endurance and Margin Test as described in item 2.2.9 of RG 1.5. die reducing the wear and tear. The proposed load band for the remaining 22 hours2.546296e-4 days <br />0.00611 hours <br />3.637566e-5 weeks <br />8.371e-6 months <br /> of SR 3.8.1.13 is consistent with the guidance of RG 1.9, Revision 3. Therefore, the proposed change is acceptable.
Based on the above, the staff finds that the proposed load bands for SRs 3.8.1.3 and 3.8.1.13 represent an e::ception to the original licensing basis commitment to RG 1.108. However, with the exception of the 2-hour load band proposed for SR 3.8.1.13, they are consistent with the guidance of RG 1.9, Revision 3, which has replaced RG 1.108. For the one exception to Section 2.2.9 of RG 1.9 for the 2-hour portion of loading (SR 3.8.1.13), the loading still exceeds the maximum expected loading on the EDGs under the worst case scenario. The proposed changes will continue to demonstrate that the EDGs are capable of perfornJng their intended safety functions under worst case conditions, while reducing wear and tear due to testing.
Based on our evaluation, we conclude that the proposed changes are acceptable.
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3.0 STATE CONSULTATION
in accordance with the Commission's regulations, the Georgia State official was notified of the proposed issuance of the amendments. The State official had no comments.
4.0 ENVIRONMENTAL CONSIDERATION
The amendments change requirements with respect to installation or use of a facility component located within the restricted area as defined in Title 10 of the Code of Federal Regulations (10 CFR) Part 20 and change surveillance requirements. The NRC staff has i
determined that the amendments involve no significant increase in the amounts and no significant change in the types of any effluents that may be released offsite and that there is no significant increase in individual or cumulative occupational radiation exposure. The Commission has previously issued a proposed finding that the amendments involve no significant hazards consideration, and there has been no public comment on such finding (64 FR 43780). Accordingly, the amendments meet the eligibility criteria for categorical exclusion set forth in 10 CFR 51.22(c)(9). Pursuant to 10 CFR 51.22(b) no environmental impact statement or environmental assessment need be prepared in connection with the issuance of the amendments.
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5.0 CONCLUSION
i The Commission has concluded, based on the considerations discussed above, that: (1) there j
is reasonable assurance that the health and safety of the public will not be endangered by operation in the pr'oposed manner, (2) such activities will be conducted in compliance with the Commission's regulations, and (3) the issuance of the amendments will not be inimical to the common defense and security or to the health and safety of the public.
Principal Contributor: N. Trehan Date:
October 25, 1999 l
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