ML20217E850
| ML20217E850 | |
| Person / Time | |
|---|---|
| Site: | Farley  |
| Issue date: | 10/01/1997 |
| From: | NRC (Affiliation Not Assigned) |
| To: | |
| Shared Package | |
| ML20217E828 | List: |
| References | |
| NUDOCS 9710070254 | |
| Download: ML20217E850 (4) | |
Text
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'a UNITED STATES g
j NUCLEAR REGULATORY COMMISSION "i
,e WASHINGTON D.C. 30666 0001 o% *****[
SAFETY EVALUATION BY THE OFFICE OF NUCLEAR REACTOR REGULATION RELATED TO AMENDMENT NO.129 TO FACILITY OPERATING LICENSE NO. NPF-2 l
AND AMENDMENT NO.122 TO FACILITY OPERATINQ LICENSE NO. NPF-8 AND INTERPRETATION OF EMERGENCY DIESEL GENERATOR TECHNICAL SPECIFICATION 4.8.1.1.2.e EOUTHERN NUCLEAR OPERATING COMPANY. INC.
JOSEPH M. FARLEY NUCLEAR PLANT. UNITS 1 AND 2 DOCKET NOS. 50-348 AND 50-364
1.0 INTRODUCTION
By letter dated May 28,1997, the Southem Nuclear Operating Company, Inc. (SNC) et al.,
submitted a request for changes to the Joseph M. Farley Nuclear Plant (Farley), Units 1 and 2, Technical Specifications (TS). The requested change revises the TS for load rejection testing of the shared emergency diesel generators (EDGs) 12A and 1C at Farley. The proposed TS amendment would add a footnote that the load rejection test for shared EDGs that is performed by aligning the EDGs with one unit may be used to satisfy the same SR requirement for the other unit, thus, avoiding redundant testings for the shared EDGs. This amendment will provide clarification for testing of each shared EDG to comply with SR 4.8.1.1.2.e, which is required once per 5 years on a per EDG basis, not on a per unit basis.
By letter dated May 22,1997, SNC requested an interpretation of the load rejection testing for the two shared emergency diesel generators (EDGs),1-2A and 1C, at Farley. Pertinent portions of each units TS SR 4.8.1.1.2.e require those shared EDGs to withstand a 1200-2400 kW load rejection every 5 years. SNC has been performing the subject SR by aligning one of the shared EDGs (EDG 1-2A) to Unit 1, and aligning the other EDG (EDG 1C) to Unit 2.
Since the load rejection test is performed to verify the operability of the EDG voltage regulator and govemor, the test does not depend on the loadr to which these units are connected. SNC contends that testing both EDGs 1-2A and 1C on a per unit TS basis would represent redundant and excessive testing of the EDGs and is not necessary. Thus, SNC concluded that its current testing method satisfies the TS SR 4.8.1.1.2.e provision for the shared EDGs at
- , 9riey. However, a concem was raised by the NRC rssident inspectors regarding the EDG testing and documented in an NRC Inspection Report 50-348/97-05 and 50-364/97-05, dated June 9,1997. As a result, SNC requestad this TS interpretation.
9710070254 971001 PDR ADOCK 05000348 P
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i 2.0 EVALUATION l;
The current TS SR 4.8.1.1.2.e for Farley Units 1 and 2 states that:
At least once per 5 years, on a staggered basis, by verifying that the emergency 1
i diesel generator can reject a load of 1200-2400 kW without tripping. The emergency diesel generator output breaker (s) must remain closed such that the i
emergency diesel generator is connected to at least one emergency bus. Verify
- that all fuses and breakers on the energized emergency bus (es) are not tripped?
_ The generator voltage shall remain within 3330 and 4990 volts during and following the load rejection.
The licensee proposed to add a footnote (") at the end of the above provision on Unit 1 (Unit 2) j that states:
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Testing of the shared Emergency Diesel Generator (EDG) set (EDG 1-2A or EDG 1C) on Unit 1 (Unit 2) may be useo to satisfy this surveillance requirement i
for those EDGs.
j
~ There are five EDGs for the two units at Farley. Train B of the two units has one large (4075 kW) dedicated EDG for each unit (designated as 18 and 28). In addition, there are three other EDGs, one large 4075 kW (1 2A) and two small 2850 kW (1C and 2C) that are shared by both units and are provided with interlocks to prevent supplying power to Unit 1 and Unit 2-simultaneously. EDGs 1-2A and 1C serve Train A of eittier unit, while diesel 2C is dedicated for i
station blackout events and supplies power to the B train of either unit. Since the B train has no.
j shared EDGs, the interpretation of TS SR 4.8.1.1.2.e applies to the shared EDGs in the A train.
Each EDG is provided with an EDG engine overspeed trip to prevent damage to the engine.
Recovery from the transient caused by the loss of a large load could cause the diesel engine to overspeed, which, if the overspeed is excessive, might result in a trip of the engine.' The load
. rejection test is performed periodically to verify the ability of the EDG voltage regulator and govemor to respond such that voltage and frequency transients continue to remain within acceptable limits and the EDG does not trip during a load rejection. This test would ensure that the EDG govemor and voltage regulator are performing correctly and would va.idate the operability of the EDG.
Because EDGs 1-2A and 1C are designed to be shared between two units and each unit maintains a separate TS at Farley, SNC has been performing the subject SR once per 5 years by aligning EDG 1-2A to a Unit 1 emergency bus and aligning EDG 1C to a Unit 2 emergency bus. -The NRC inspector questioned whether the EDGs 1-2A and 1C should be tested on a per unit basis, such that each shared EDG is tested twice per 5 years; for example, tested once -
with Ur.it 1 and tested again with Unit 2.
3-SNC contends that testing on a per unit basis represents redundant and excessive testing of the EDG and is not necessary for the following reasons:
1.
The load rejection test is conducted to validate the EDG fur.ction by verifying the ability of the voltage regulator or govemor to maintain the load within acceptable limits during a load rejection. Thus, the test results depend on the equipment within the EDGs themselves, not on the EDG loads used for the test. If there is a problem with the EDG voltage regulator or governor, it would be evident reg >rdless of the loads that are connected to it or which unit the load came from.
2.
When the staff granted the load rejection testing frequency from every 18 months to every 5 years as shown in the current TS SR 4.8,1.1.2.e, the testing was intended for each EDG on an EDG by EDG basis, not on a unit by unit basis.
3.
If the shared EDGs, are required to be tested on a per unit basis, the (shared) EDGs in the A train would be performing the load rejection test twice as often as the (dedicated)
EDGs in the B train.
4.
Having five diesel generators that have either an automatic or manual capability to load one of the two safety trains represents much greater flexibility than having four dedicated EDGs installed in two trains as shown in the NRC's Standard TS. Thus, in terms of reduced surveillance and testing requirements for EDGs, credit can be given to the Farley TS in order to avoid redundant testings.
The staff has reviewed the proposed TS amendments and SNC's TS SR 4.8.1.1.2.e interpretation. The staff concludes that the purpose of TS SR 4.8.1.1.2.e is to demonstrate that the voltage regulator and governor in each EDG are performing correctly. TS SR 4.8.1.1.2.e tests the EDGs themselves, not the EDG loads. Therefore, the staff concurs with SNC's interpretation that the testing requirement for the shared EDGs (1-2A and 1C) is satisfied by aligning these EDGs to either Unit 1 cr Unit 2 independently, as long as their operability is confirmed once per 5 years. The staff finds that testing of the shared EDGs on one unit to satisfy SR 4.8.1.1.2.e requirements for both units and the addition of the proposed footnote (")
at the end of SR 4.8.1.1.2.e for Unit 1 and Unit 2 to be acceptable.
3.0 STATE CONSULTATION
in accordance with the Commission's regulations, the State of Alabama official was notified of the proposed issuance of the amendments. The State official had no comments.
4.0 ENVIRONMENTAL CONSIDERATION
The amendments change the surveillance requirements. The NRC staff has 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 nas been no public comment on such finding (62 FR 33135, June 18,1997).
y,
.- 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 environmentalimpact statement or environmental assessment need be prepared in connection with the issuance of the I
amendments.
5.0 CONCLUSION
The Commission has concluded, based on the considerations discussed above, t'.it (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 amendments will not be inimical to the common defense and security or to the health and safety of the public.
PrincipalContributor. P. Kang Date:
October 1, 1997 l
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