ML20137V492
| ML20137V492 | |
| Person / Time | |
|---|---|
| Site: | Millstone  |
| Issue date: | 04/15/1997 |
| From: | NRC (Affiliation Not Assigned) |
| To: | |
| Shared Package | |
| ML20137V479 | List: |
| References | |
| NUDOCS 9704170319 | |
| Download: ML20137V492 (3) | |
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k UNITED STATES
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j NUCLEAR REGULATORY COMMISSION l
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WASHINGTON, D.C. 30566-0001 I
.....,o SAFETY EVALUATION BY THE OFFICE OF NUCLEAR REACTOR REGULATION RELATED TO AMENDMENT NO.137 l
TO FACILITY OPERATING LICENSE NO. NPF-49 NORTHEAST NUCLEAR ENERGY COMPANY. ET AL.
MILLSTONE NUCLEAR POWER STATION. UNIT NO. 3 l
DOCKET NO. 50-423 i-1.0
. INTRODUCTION By letter dated March 4, 1996, the Northeast Nuclear Energy Company, et al.
(the licensee), submitted a request for changes to the Millstone Nuclear-Power Station, Unit No. 3 Technical Specifications (TS). The requested changes would modify Surveillance Requirements (SR) 4.8.1.1.2.a.6, 4.8.1.1.2.b, and 4.8.1.1.2.g.7 by specifying load bands in loading the diesel generator (DG) in lieu of the present requirement to load the DG greater than or equal to a given value.
A footnote is being added to the three surveillance requirements to indicate that a moment 0ry transient outside the load range shall not invalidate the test. The essociated Bases sections have been revised to reflect the above changes.
2.0 EVALUATION 2.1 Surveillance 'Reauirement 4.8.1.1.2.a.6 This SR currently requires that every month the DG be synchronized and gradually loaded in accordance with the mardfacturer's recommendation to i
greater than or equal to 4986 kW, operating with a load greater than or equal to 4986 kW.for at least 60 minutes. The licensee has aroposed to replace the current load of " greater than or equal to 4986 kW' wit 1 a load range "between 4800-5000 kW."
The staff finds that DG testing in the load range of 4800-5000 kW provides adequate assurance of the DG's capability to carry continuous rating load while ensuring that the DGs will not be overloaded.
The load range also accounts for the instrument error, operational control capabilities, and human factor characteristics. This is consistent with Regulatory Guide (RG) 1.9, Revision 3, " Selection, Design, and Qualification of Diesel-Generator Units used as Standby (Onsite) Electrical Power Systems at Nuclear Power Plants;" therefore, the staff finds this change acceptable.
2.2 Surveillance Reauirement 4.8.1.1.2.b This SR currently requires that at least once every 184 days, it should be verified that the DG starts and attains generator voltage and frequency of 4160 i 420 volts and 60 i 0.8 Hz within 11 seconds after the start signal.
9704170319 970415 PDR ADOCK 05000423 P
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t The generator shall be synchronized to the associated emergency bus, loaded to greater than or equal to 4986 kW, in accordance with the manufacturer's recommendations, and operated with a load greater than or equal to 4986 kW for at least 60 minutes. The licensee has proposed to replace the current load of
" greater than or equal to 4986 kW" with a load range "between 4800-5000 kW."
As siated above, the staff finds the DG testing in the load range of i
4800-5000 kW consistent with the recommendations of RG 1.9, Revision 3, and
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j acceptable.
-2.3 Surveillance Reauirements 4.8.1.1.2.a.7 i
This SR currently requires that the DG operate for at least 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br />. During 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, the DG should be loaded to greater than or equal to 5485 kW, and during the remaining 22 hours2.546296e-4 days <br />0.00611 hours <br />3.637566e-5 weeks <br />8.371e-6 months <br /> of this test, the DG i
should be loaded to greater than or equal to 4986 kW.
The licensee has proposed to replace the current load of " greater than or equal to 5485 kW" with a load range "between 5400-5500 kW" for 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 l
and replace the current load of " great.ar than or equal to 4986 kW" with a load range "between 4800-5000 kW" for the remaining 22 hours2.546296e-4 days <br />0.00611 hours <br />3.637566e-5 weeks <br />8.371e-6 months <br /> of this test. The
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staff finds the above load ranges consistent with the recommendations of i
RG 1.9, Revision 3, and acceptable.
2.4 Other The licensee has proposed adding a footnote, which will be applicable to all the SRs. This footnote will allow momentary excursions outside the load ranges specified in the SRs without invalidating the test. The staff finds that the footnote clarifies the specific SR requirements, as will as provides more operational flexibility.
In addition, this footnote is consistent with the Improved Standard Technical :;pacifications and, therefore, is acceptable.
Bases Sections 3/4.8.1, 3/4.8.2, and 3/4.8.3 have also been revised to reflect the above changes to SRs 4.8.1.1.2.a.6, 4.8.1.1.2.b, and 4.8.1.1.2.g.7.
This change is administrative in nature and has no impact on plant safety.
2.5 Overall The staff concluded that use of open-ended language such as " greater than or equal to" has the potential for overloading the DGs because of tb9 instrument inaccuracies and human factor characteristics.
Specifying a load range could eliminate this potential and ponibly improve DG reliability. The specified load range of 4800-5000 kW for a coctinuous rating of approximately 5000 kW and 5400-5500 kW for 110 percent of a continuous load rating of approximately 5500 kW provides adequate assurance of tia DG's capability to carry continuous and overload rating while ensuring that the DGs will not be overloaded.
These load ranges also take into account the instrument error, operational control capabilities, and human factor characteristics. Additionally, the above changes are consistent with RG 1.9, Revision 3, which recommends loading of the DGs between 90-100 percent of the continuous and short-term rating to avoid overloading of the DGs due to instrument inaccuracies. On this basis, the staff finds the proposed changes acceptable.
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3.0 STATE CONSULTATION
In accordance with the Comission's regulations, the Connecticut State official was notified of the proposed issuance of the amendment. The State i
official had no coments.
4.0 ENVIRONMENTAL CONSIDERATION
The amendment changes-surveillance requirements. The NRC staff has determined that the amendment involves no significant increase in the amounts, and no significant change in the types, of any effluents that may be released i
offsite, and that there is no significant increase in individual or cumulative occupational radiation exposure. The Comission has previously issued a proposed finding that the amendment involves no significant hazards consideration, and there has been no public coment on such finding (62 FR 11496 dated March 12,1997). Accordingly, the amendment meets 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 amendment.
5.0 CONCLUSION
The Comission has 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 proposed manner, (2) such activities will be conducted in compliance with the Comission's regulations, and (3) the issuance of the amendment will not be inimical to the comon defense and security or to the health and safety of the public.
Principal Contributor: Om Chopra Date: April 15, 1997
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