ML20057D593
| ML20057D593 | |
| Person / Time | |
|---|---|
| Site: | Farley  |
| Issue date: | 09/22/1993 |
| From: | Office of Nuclear Reactor Regulation |
| To: | |
| Shared Package | |
| ML20057D592 | List: |
| References | |
| NUDOCS 9310050022 | |
| Download: ML20057D593 (5) | |
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. [*S%s UNITED STATES 3
NUCLEAR REGULATORY COMMISSION g.,,e WASHINGTON, D.C. 20555-0001 f
SAFETY EVALUATION BY THE OFFICE OF NUCLEAR REACTOR REGULATION RELATED TO AMENDMENT NO. 101 TO FACILITY OPERATING LICENSE NO. NPF-2 l
AND AMENDMENT N0. 93 TO FACILITY OPERATING LICENSE NO. NPF-8
'I SOUTHERN NUCLEAR OPERATING COMPANY. INC.
I JOSEPH M. FARLEY NUCLEAR PLANT. UNITS 1 AND 2 I
DOCKET NOS. 50-348 AND 50-364 i
1.0 INTRODUCTION
I By letter dated March 4, 1993, as supplemented June 29, 1993, the Southern Nuclear Operating Company, Inc. (the licensee), submitted a request for f
changes to the Joseph M. Farley Nuclear Plant, Units 1 and 2 (Farley),
i Technical Specifications (TS).
The June 29, 1993, letter provided clarifying information that did not' change l
the initial proposed no significant hazards consideration determination.
On July 21, 1988, Part 50 of 10 CFR was amended to include a new Section 50.63, Loss of all alternating current power.
This condition of a complete loss of AC electrical power to a nuclear power plant is referred to as a i
station blackout (SB0).
The SB0 rule requires each nuclear power plant to be capable of maintaining core cooling and appropriate containment integrity to withstand and recover from an SB0 of a duration' based upon the specific site l
characteristics.
l The licensee provided a response to the SB0 rule by letters dated April 12, 1989, and March 8, 1990. They proposed modifications to the emergency electrical power system to designate one of the existing emergency diesel
. generators (EDG) as an alternate AC (AAC) power source as defined in Regulatory Guide (RG) 1.155, " Station Blackout."
In its Safety Evalt/ation (SE) dated April 25, 1991, the NRC staff concluded that.the proposed use of an existing EDG as an AAC is an acceptable means of resolving the SB0 issue.
Additional information about hardware and procedural modifications was requested by the NRC staff and was subsequently providad by the licensee's June 5, 1991.
In this letter, the licensee stated that the SB0 modifications i
that will designate existing diesel generator (DG) 2C as an AAC will be' implemented during the Unit I twelfth and Unit 2 ninth refueling outages.
l These modifications will ensure that the train 8 safe shutdown loads in the i
SB0 unit can be powered by DG 2C by manual actions from the control room
'l within 10 minutes of the determination of a blackout event. When designated as the AAC power source the DG 2C will not automatically start during any design basis event. Staff approval of the licensee response to the SB0 rule 4
was provided by the staff in a letter dated August 14, 1992.
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. Following the SB0 modifications, DG 2C will no longer be relied upon to perform the function of an emergency power source for design basis events (i.e., automatically starting upon a safety injection or loss of offsite power (LOSP) signal). Therefore, in a letter dated March 4, 1993, the licensee proposed to revise TS 3/4.8.1 and 3/4.8.2 to delete all references to its use as a design basis diesel generator.
DISCUSSION As provided in the June 5,1991, licensee response, DG 2C will be dedicated as an AAC power source for SB0 events and will be connectable from the control room to the train 8 safe shutdown buses in either unit.
The few safe shutdown loads (approximately 150 kW total for both units) currently being supplied by DG 2C will be supplied by EDGs IB or 2B. With the remaining four EDGs, both units will continue to comply with the licensing basis for all design basis accidents, considering a single failure, without taking credit for DG 2C.
The capacity of the remaining EDGs and their alignment will provide adequate power for safe shutdown loads during the worst case loading scenarios (i.e., LOSP in both units concurrent with a loss-of-coolant accident in one unit).
The loads previously powered by DG 2C will now be powered by EDGs IB or 28.
The impact of the additional shutdown loads formerly supplied from DG 2C has been analyzed by the licensee. This analysis determined that EDGs 18 and 2B will continue to have sufficient capacity to energize a complete safety train of shutdown loads of one unit during its worst case scenario.
Further, this analysis contains a revised diesel generator loading calculation.
The results from this calculation were provided to the staff by the licensee.
These results show that for the worst case loading scenarios the continuous rating (4075 Kw) of EDGs 18 and 2B.is not exceeded.
The train A EDG loading will be unaffected by the SB0 modifications and will continue to have sufficient i
capacit.y to supply power to a complete safety train during all design basis events.
Therefore, the elimination of DG 2C from the TS as an emergency power i
source during design basis events so it may be used as the AAC in case of SB0 will not significantly diminish the ability of the emergency. electrical power system to cope with the worst case design basis event.
2.0 EVALUATION t
Proposed revisions to the Unit I and Unit 2 TS Sections 3/4.8.1, A.C. Sources, are addressed below.
References To Diesel Generator 2C Deleted From TS Sections 3/4.8.1 and 3/4.8.2. and Revisions to TS Section 6.8.1 The current TS for Farley contain five EDGs for both units.
Each of these EDGs has a 10 day allowed outage time (A0T).
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, l The 10 day A0T was approved by the NRC staff based on the flexibility of the Farley onsite electrical power system design.
Three EDGs identified as 1-2A, IB, and 2B are rated at 4075 kW each, and two EDGs identified as IC and 2C are rated at 2850 kW each.
Emergency diesel generators 1-2A and IC are assigned to the load group Train A, while EDGs IB, 28, and 2C are assigned to load group Train B.
Emergency diesel generator 1B is dedicated to Unit 1, while EDG 2B is dedicated to Unit -2.
Emergency diesel generators 1-2A and 1C swing between the two units and EDG 2C is shared between the two units in certain accident scenarios.
Prese.
'y, DG 2C automatically starts upon a LOSP or a safety injection signal and pc.
only some small miscellaneous safe shutdown loads (150 kW for both The elimination of DG 2C as an emergency power source, as pro) posed, 4
units.
does not significantly impact the remaining four EDGs ability to supply all needed shutdown loads during the worst case design basis accident.
The licensee asserts that a high degree of flexibility is provided in the Farley.
i design because of the ability to align DG 2C to both B-train emergency buses and manually connect shutdown loads, if necessary. When this argument is examined in light of the SB0 modifications that included the addition of an automatic sequencer for shutdown loads and removal of the automatic start feature from DG 2C, it remains valid.
Ordinarily, the staff would not accept a DG that was neither covered by the TS, nor had an automatic start feature as acceptable for mitigating a design basis event and because DG 2C is used not only for an AAC power source, but also as a basis for extended A0Ts, this was an issue that the staff carefully evaluated.
Nevertheless, the loss of the automatic start feature is compensated for by a number of other factors.
i Following completion of implementation of the SB0 modifications, the operator continues to have the ability to manually start DG 2C and the flexibility to select and add shutdown loads to either of the Unit 1 or Unit 2 B-train emergency buses from the control room.
In H 'ition, the operator will not i
have to perform any breaker realignments in order to connect DG 2C to the B-train safe shutdown emergency buses (i.e., 1G or 2G and ll and 2L) as is currently required.
Thus, the degree of flexibility of the Farley emergency AC electrical power system design is not significantly diminished.
- Further, i
in order to ensure that DG 2C is maintained in a high state of readiness so that the flexibility afforded by its use is not significantly diminished, the i
licensee is to implement a reliability program that will ensure its reliability is maintained at.95 or greater.
This program defines the l
testing, maintenance, and parts procurement requirements necessary to maintain the AAC as a Class lE component.
In a submittal dated June 29, 1993, the licensee provided revisions to TS Section 6.0, Administrative' Controls.
}
These revisions revise Section 6.8.1 to address the AAC reliability program and to indicate that NRC is to be notified if the AAC is out of service for greater than 10 days.
This submittal also documents the licensee's policy of 4-
y 9 l 1
not intentionally removing two diesel generators from service at the same time.
In sumary, the four. factors mitigating the removal of the DG 2C from the TS and the removal of the auto start from DG 2C are:.(1) the capacity of the remaining four EDGs incl ~uded in the TS is sufficient to handle design basis accident loads without exceeding their continuous ratings, (2) the addition of an automatic sequencer to DG 2C increases the speed and simplicity of loading that DG, (3) maintenance of the 2C DG as a Class IE diesel generator, and (4) the flexibility available for manually loading DG 2C.to handle a wide variety of accidents.
l l
On the bases of the above, the staff finds the proposed. revisions to the delete references to DG 2C in TS Sections 3/4.8.1 and 3/4.8.2 are acceptable.
In addition, the staff finds the proposed revisions to TS section 6.8.1 to be acceptable.
l Revisions to the Emeroency Diesel Generator Accelerated Testina Schedule Based Voon Nuclear Management and RR19.MT_G.tL.G.9.RDgi l MAELG u i d Nig -
The licensee proposed revisions to TS Table 4.8-1 that revises' the diesel generator accelerated testing schedule. A proposed revision requires testing-an EDG every 7 days if the number of failures in the last 25 valid tests is i
greater than or equal to 4.
If the number of failures is equal to or less than~ 3 in the last E voiiu tests, an EDG is to be tested every 31 days.
The staff is currently performing a generic review involving the issue of j
accelerated testing of EDGs and the related specific staff guidance has not been finalized. Therefore, the_ staff is unable to complete its review of this issue at this time.
Deletion of 600 Volt load Centers J and H as listed in TS Section 3/4.8.2 By letter dated December 30, 1982, the licensee requested that the requirements associated with the river water system be _ deleted from the Farley TS.
This request was approved by the NRC staff by License Amendments 45 and 36, for Units 1 and 2, respectively.
The justification for removing 600 volt i
load centers J and H from the TS was provided in the Safety Evaluations for these license amendments. However, references to the 600 volt load centers J.
and H, which supply power to the river water pump auxiliaries, were not deleted from TS Section 3.8.2.1.
Therefore, the proposed deletions provide corrections and are administrative changes. Thus, the staff finds them acceptable.
Revision of the Reauirements of TS Section 6.9.1.12 for the' Annual Emeroency Diesel Generator Reliability ReDort The licensee proposed revisions to TS Section 6.9.1.12.
These revisions revise the information that should be contained in the Emergency Diesel Generator Reliability Report. that is submitted annually to the NRC. The proposed revisions change the content of this annual report to include the calculated unit reliability as required by the SB0 rule.
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6 The staff is currently performing a generic review related to the special reporting requirements of EDGs and the related specific staff guidance has not been finalized. Therefore, the staff is unable to complete its review of this I
issue at this time.
SUMMARY
The proposed revisions to the Farley electrical power system TS resulted from licensee's resolutions to the SB0 rule. These resolutions have been previously reviewed and approved by the NRC staff.
Regarding the proposed revisions to TS Table 4.8-1 and the proposed revisions to TS Section 6.9.1.12, the staff is currently performing a generic review and related staff guidance has not been finalized at this time.
With the exception of the above two issues, we conclude that the proposed revisions will not significantly increase the probability or consequences of any accident previously evaluated, create the possibility of a new or different kind of accident from any accident previously evaluated, or involve a significant reduction in the margin of safety.
Thus, these proposed revisions for the Farley TS are acceptable.
3.0 STATE CONSULTATION
In accordance with the Comission's regulations, the State of Alabama official l
was notified of the proposed issuance of the amendment. The State official had no coments.
4.0 ENVIRONMENTAL CONSIDERATION
The amendment changes a requirement with respect to installation or use of a j
facility component located within the restricted area as defined in 10 CFR i
Part 20 and changes the 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 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 (58 FR 39060). 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:
D. Nguyen F. Ashe Date:
September 22, 1993 i