ML20059J227
| ML20059J227 | |
| Person / Time | |
|---|---|
| Site: | Waterford  |
| Issue date: | 11/02/1993 |
| From: | Office of Nuclear Reactor Regulation |
| To: | |
| Shared Package | |
| ML20059J224 | List: |
| References | |
| NUDOCS 9311120101 | |
| Download: ML20059J227 (3) | |
Text
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UNITED STATES
[
T,j NUCLEAR REGULATORY COMMISSION
(
WASHINGTON. D.C. 20556-0001 l
\\.... /
SAFETY EVALUATION BY THE OFFICE OF NUCLEAR REACTOR REGULATION i
RELATED TO AMENDMENT NO. 88 TO l
FACILITY OPERATING LICENSE NO. NPF-38 ENTERGY OPERATIONS. INC.
I WATERFORD STEAM ELECTRIC STATION. UNIT 3 DOCKET NO, 50-382
1.0 INTRODUCTION
l By application dated May 6, 1993, Entergy Operations, Inc. (the licensee),
i submitted a request for changes to the Waterford Steam Electric Station, i
Unit 3, Technical Specifications (TS). The requested changes would revise the surveillance requirement to increase the emergency diesel generator (EDG) voltage limit during the load rejection test to address the safety issues identified in NRC Information Notice (IN) 91-13, " Inadequate Testing of Emergency Diesel Generators."
2.0 BACKGROUND
NRC Information Notice (IN) 91-13, " Inadequate Testing of Emergency Diesel Generators," was issued to alert licensees to inadequacies in the testing of emergency diesel generators (EDGs) at nuclear power plants.
Specifically, some EDG testing had not adequately verified the capability of the EDG to carry the maximum expected loads; the reactive power delivered by the EDG on loss of load had not been adequately addressed in determining the maximum EDG load rejection test voltage. Upon evaluating IN 91-13, Waterford 3 subsequently increased the reactive power delivered by the EDG during surveillance testing, which resulted in a higher steady-state EDG voltage.
The increase in the higher steady-state EDG voltage in turn resulted in the need to increase the TS limit for the maximum EDG voltage during the load rejection test, thus prompting the following proposed change.
3.0 EVALUATION Information Notice 91-13 was intended to alert addresses to inadequacies in the testing of emergency diesel generators at nuclear power plants.
Specifically, some EDG testing has not adequately verified the capability of the EDG to carry maximum expected loads. The intent of the required testing is to assure that the EDG can dependably carry accident loads.
It is important that the worst-case conditions (frequency, voltage, electrical power factor, and environment) be considered when the EDG is tested. Waterford TS Surveillance Requirement 4.8.1.1.2.d.6 requires loading the EDG between 4200-4400 kW for 22 hours2.546296e-4 days <br />0.00611 hours <br />3.637566e-5 weeks <br />8.371e-6 months <br />, and between 4700-4900 kW for 2 hours2.314815e-5 days <br />5.555556e-4 hours <br />3.306878e-6 weeks <br />7.61e-7 months <br />. The 9311120101 931102 PDR ADOCK 05000382 p
current Waterford 3 TS does not adequately account for reactive power loading i
on the EDG. The EDGs at Waterford 3 have been tested at approximately 4400 kW and 1000 kVARS for 22 hours2.546296e-4 days <br />0.00611 hours <br />3.637566e-5 weeks <br />8.371e-6 months <br /> and approximately 4840 kW and 1000 kVARS for j
4 2 hours2.314815e-5 days <br />5.555556e-4 hours <br />3.306878e-6 weeks <br />7.61e-7 months <br />. The 4400 kW load is in accordance with the practices described in l
IN 91-13; however, the 1000 kVAR load is less than the expected reactive loading during a worst-case accident at Waterford 3 (2600 kVARS is expected during the worst-case accident).
In response to the IN, Waterford 3-increased the reactive power load to a range of 2700 to 3300 kVARS during surveillance testing. However, this increase in reactive power resulted in a higher l
EDG steady state voltage and the EDG exceeding the TS limit of 4875 volts i
during the subsequent load rejection test.
The licensee discussed the test results with the manufacturer and it was l
determined that the EDG was being tested in accordance with limits that were too stringent. The manufacturer claimed that it may not be possible for the EDG voltage to be less than the present limit of 4784V during the load rejection test if the steady state voltage prior to the test is greater than 4160V. The manufacturer recommended that the maximum steady state voltage 1
(4400V) of the EDG plus 15% (5060V) would be an acceptable upper limit for the EDG voltage during the load rejection test and would not-result in component damage.
In order to determine a conservative EDG voltage limit during the load rejection test, EDG performance was considered at its upper steady state 1
voltage. The EDG is rated to perform within the limits of its capability l
curve at a maximum voltage of 4160V plus 5% (4368V). Thus, a value of 4368V plus 15% (5023V) was chosen. This value for the EDG voltage limit satisfies the capability curve of the diesel, the manufacturer recommendations, and will also allow the EDG to be tested in accordance with the practices described in NRC IN 91-13.
In our review, we had concerns regarding the length of time at the voltage level of 5023V, load damage, and high starting currents of large motors due to the increased voltage.
It was confirmed by the licensee that the EDG would only remain at the voltage level of 5023V for a few seconds and that there would be no damage to the EDG or its connected loads due to the short duration of the increased voltage.
Finally, there would be no risk of large motor starting currents because no motors would be started during EDG surveillance testing.
The TS change permits more meaningful EDG load rejection testing without risk of damage to the EDG or its connected loads.
Further, the change is supported by the manufacturer and enables the licensee to address issues identified in NRC IN 91-13. Based on the above information, the proposed change is acceptable.
4.0 STATE CONSULTATION
In accordance with the Commission's regulations, the Louisiana State official was notified of the proposed issuance of the amendment. The State official had no comments.
5.0 ENVIRONMENTAL CONSIDERATION
i The amendment changes a requirement with respect to installation or use of a facility component located within the restricted area as defined in 10 CFR Part 20 and 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 l
occupational radiation exposure. The Commission has previously issued a pro-posed finding that the amendment involves no significant hazards consideration and there has been no public comment on such finding (58 FR 34078).
Accordingly, the amendment meets the eligibility criteria for categorical i
exclusion set forth in 10 CFR 51.22(c)(9).
Pursuant to 10 CFR 51.22(b) no i
environmental impact statement or environmental assessment need be prepared in connection with the issuance of the amendment.
i
6.0 CONCLUSION
The Commission 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 Commission's regulations, and (3) the issuance of the amendment will not be inimical to the common defense and security or to the health and safety of the public.
Principal Contributor:
M. D. Pratt i
Date: November 2, 1993