ML20140A386

Application for Amends to Licenses NPF-2 & NPF-8,clarifying That Testing of Each Shared EDG to Comply W/Sr 4.8.1.1.2.e Is Only Required Once Per Five Years on a Per EDG Basis,Not on Per Unit Basis

ML20140A386
Person / Time
Site:	Farley
Issue date:	05/28/1997
From:	Dennis Morey SOUTHERN NUCLEAR OPERATING CO.
To:	NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
Shared Package
ML20140A390	List: ML20140A386 ML20140A393
References
NUDOCS 9706040191
Download: ML20140A386 (12)

Text

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3 e 1 D:ve Mirey Southern Nuchar Vice President OpIr: ting Comp:ny Farley Project P0. Box 1295

, Birmingham. Alabama 35201 Tel 205.992.5131 May 28,1997 SOUTHERN L COMPANY Energy to Serve Your%rld" Docket Numbers: 50-348 10 CFR 50.90 50-364 U.S. Nuclear Regulatory Commission ATTN: Document Control Desk Washington, DC 20555 Joseph M. Farley Nuclear Plant Request For Technical Specification Changes Diesel Generator Load Rejection Testing Ladies and Gentlemen:

In accordance with the provisions of 10 CFR 50.90, Southern Nuclear Operating Company (SNC) proposes to amend the Farley Nuclear Plant (FNP) Unit I and Unit 2 Technical Specifications (TS), Appendix A to Operating Licenses NPF-2 and NPF-8. This amendment j revises and clarifies surveillance requirements (SRs) for the Emergency Diesel Generators (EDGs) that are shared between Unit I and Unit 2.

1 Recent NRC inspections have raised questions regarding the proper application of TS SR )

l 4.8.1.1.2.e, for load rejection testing of the two shared EDGs at FNP. The proposed change inserts a footnote to clarify that load rejection testing of the shared EDG set on either unit may be  ;

used to satisfy TS 4.8.1.1.2.e surveillance requirements for both units. This clarifies that each EDG is only required to be tested once every five years.

, Enclosure 1 provides a safety assessment for the proposed changes. Enclosure 2 provides the basis for a determination that the proposed changes do not involve significant hazards considerations pursuant to 10 CFR 50.92. Enclosure 3 provides the proposed changes to the Unit 1 TS. Enclosure 4 provides the proposed changes to the Unit 2 TS. Enclosure 5 provides the Units 1 and 2 marked-up TS pages.

As denoted in 10 CFR 50.92(c), SNC has determined the proposed changes to the TS do not l

involve a significant hazards consideration. The basis for this evaluation is provided in Enclosure

2. SNC has also determined that the proposed changes will not significantly affect the quality of the human environment. A copy of the proposed changes has been sent to Dr. D. E. Williams, the t Alabama State Designee, in accordance with 10 CFR 50.91(b)(i). )

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K S. Nuclear Regulatory Commission Page 2 SNC requests that the NRC review and approve the proposed TS changes on an expedited basis.

SNC plans to implement the proposed changes within 30 days ofissuance by the NRC.

Mr. D. N. Morcy states that he is a vice president of SNC, and is authorized to execute this oath on behalf of SNC and that, to the best of his knowledge and belief, the facts set forth in this letter and enclosures are true. ,

I Respectfully submitted, SOUTHERN NUCLEAR OPERATING COMPANY hh hb6 Dave Morey l

Sworn to andwbscribedb re me this Ye? -- dav of _ kW l997 7Ma.ude 3W

( Notary Public F My Commission Expires:N L

[ NYY EFB/ cit:dgtsame2. doc Enclosures- I I

1. Basis for the TS Change i

2. 10 CFR 50.92 Evaluation

3. Unit 1 Technical Specification Page

4. Unit 2 Technical Specification Pages

5. Units 1 and 2 Marked-Up Technical Specification Pages cc: Mr. L. A. Reyes, Region II Administrator j

Mr. J.1 Ziminerman, NRR Project Manager l

Mr. T. M Rass, Plant Sr. Resident Inspector Dr. D. E. Williamson, State Department of Public Health l

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,.,- - t Enclosure 1 Joseph M. Farley Nuclear Plant Emergency Diesel Generator Load Rejection Testing Technical Specification Changes Basis for the TS Chanee I

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Enclosure 1 Joseph M. Farley Nuclear Plant Emergency Dicel Generator Load Rejection Testing Technical Specification Changes Basis for the TS Chance Description of Chances;

{ Recent NRC inspections have raised questions regarding the proper application of TS SR 4.8.1.1.2.e, fo.

I lo; 1 rejection testing of the two sbared EDGs at FNP. The purpose of this TS change is to clarify that testing of each shared EDG to comply with SR 4.8.1.1.2.c is only required once per five years on a per EDG basis, not on a per unit basis. The proposed changes include a footnote for clarification. The footnote states that the testing of the shared emergency diesel generator (EDG) set (EDG l-2A or EDG 1C) on one unit may be used to s-tisfy the other unit',3..rveillance requirement for those EDGs."

General Discussion:

'The EDGs that are shared between Unit I and Unit 2 ar; nDG l-2A and EDG IC. Testing of the shared EDGs in accordame with SR 4.3.1.1.2.e can be satisfn d in testing the EDGs on either unit. The load rejection of 1200-2400 kw is accomplished by opening dreaker other than the EDG output breaker. This keeps the EDG connected to at least one emergency bus such that the effects of the load rejection are i.pposed upon that bus. Therefore, assurance is given that each EDG is operable, and that the effect of load rejection on cach EDO does not cause adverse impacts to the emergency buses and the connected loads of each unit. This testing assures that EDG governor and voltage regulators are performing correctly. SR 4.8.1.1.2.e is a test of the EDGs themselves, not the EDG loads. EDG loads are subjected to more severe testing as noted in the following technical discussion. Testing each unit with bo'.h the 1-2A and 1C EDGs j would require that each shared EDG be tested twice per five years instead of once per five years. This represents redundant and excessive testing of the ECGS and is not required.

Technical Discussion:

The load rejection testing validates that the EDGs ftmetion as required and do not subject plant loads to unacceptable transient, dynamic, and steady state effects due to generator output voltr.ge and frequency.

Th:s position is supported by the similarity in design between Units 1 and 2 distribution systems. The following is an assessment of the requirements in step SR 4.8.1.1.2.e of the TS: (Note: The B train EDGs have no shared components and are therefore not addressed.)

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Hasis fdr the TS change i

i SR 4.8.1.1.2.e requires verification that the EDG can reject a load of 1200 - 2400 KW without tripping.

The purpose of this requirement is to test the EDGs themselves. Testing each unit with both the 1-2A and 1C EDGs every five years would represent redundant and excessive testing of the EDGs (twice the frequency of the B-train EDGs) and is not required. EDG l-2A is tested at least once every 5 years by rejecting a load of 1200-2400 KW without tripping. EDG IC is tested at least once every 5 years by rejecting a load of 1200-2400 KW without tripping. Therefore, each EDG that aligns to Unit I and Unit 2 meets this requirement.

SR 4.8.1.1.2.e requires that the EDG breaker (s) remain closed such that the EDP is connected to at least I one emergency bur ' Die purpose of this requirement is to insure that the load rejection test is not accomplished by tripping the respective EDG output breaker. Rather, the EDG output breaker is to remain closed such that after the load rejection, at least one bus with representative emergency loads is connected and subjected to the transient, dynamic, and steady state impacts that occur due to the EDG voltage

, regulator and governor response to the load rejection. The TS do not identify the specific bus and loads tc

be subjected to these efTects, only the KW amount ofload. At least one emergency bus of Unit I and Unit i I

2 is connected and subjected to an EDG load rejection and corresponding dynamic transient (s).

When EDG IC and EDG l-2A are tested on either unit, their respective output breaker remains closed such that the connected loads (which are similar for each unit) have been subjected to the various dynamics mentioned above. This is acceptable because the purpose of the testing is to periodically check the ability of the EDG voltage regulator and governor to respond such that voltage and frequency transients continue to remain within acceptable limits during a load rejection. Each EDG dynamic transient (vol" ige and speed) is recorded and checked to insure that it is v h. the acceptance criteria. The acceptance criteria for dynamic response is based upon industry standM:, diat define acceptable limits and provide assurance that output breakers, connected loads, and protective bices will not be adversely impacted.

The purpose of the load rejection test is not to test each EDG output breaker. The breaker itself(on each

unit) is tested by other surveillance testing at least once every 1 L months.

SR 4.8.1.1.2.e requires verification that all fuses and breakers on the energized emergency bus (es) are not tripped. The purpose of this requirement is to serify that tle EDG voltage regulator rM governor responses to the load rejection remain within acceptable limits. In addition to the recordings of the frequency and vohage transient.c mentioned above, verification that the fuses and breakers do not trip provides validation that the regulator and governor are continuing to function properly. Validating dat the dynamic response characteristics of each EDG are within acceptable limits also provides assurance that each of the EDG dynamic response characteristics are similar.

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0 Basis fdr the TS change The proposed testing will monitor each EDG voltage and frequency response to the specified load rejection and insure that at least one emergency bus and representative loads are subjected to the resulting (transient, dynamic; and steady state) efTects of a load rejection. 'Ihis demonstrates that these effects do not cause the loads to be disconnected. The TS do not identify the specific bus and loads to be subjected to these effects.

The specific loads may vary from one test to the next on any given EDG. For example, in one case, a charging pump may be operating, in the next case a CCW pump may be operating. Typical low voltage loads will generally be in operation during the test, such as MCC loads, battery chargers and inverter AC bypass circuits. I In addition, the connection of specific loads (to verify the impact to these loads of an EDG load rejection) is  !

not necessary for the following reasons. First, the loads and associated fuses and breakers are very similar ,

between Unit I and Unit 2. Next, the protective device settings provide sufficient setpoint margin such that I they should not trip for normally expected variations in supply voltage and frequency. This would include those generated by the EDGs during load rejections (The acceptance criteria for EDG dynamic response is based upon industry standards that are written to provide guidance on the allowable dynamic tolerances '

such that adverse impacts to operating loads and protective devices do not occur). Therefore, verification that the tested voltage and frequency variations continue to remain within the EDG Load Rejection STP acceptance criteria, and that representative loads do not trip, is sufficient to meet the stated requirement. .

Furthermore, the LOSP tests and SI/LOSP tests subject a larger number ofloads, including MOVs, to l comparable, and usually more severe, transient and dynamic effects than the load rejection tests. For I example, based on test data, the peak 4160V bus voltage that occurred in step 1 of a recent SI/LOSP test for the 1-2A DG was 112% of 4160V vs. only 108% for the last 1-2A DG load rejection test (Voltage time responses were comparable for both tests).

SR 4.8.1.1.2.e requires that the generator voltage rem .in wit hin 3330 and 4990 volts during and following the load rejection. The purpose of this requirement is to verify that the EDG voltage regulator continues to function properly so that it does not expose the equipn ent loads to unacceptable voltages and resultant currents in the event of a load rejection. The voltage transient from the load rejection is recorded during each load rejection test. The recordings are checked to insure that the voltage transient remairs within the acceptanca criteria. I A proble n in the voltage regulator would be evident for a 1200-2400 KW step change in load, regardless of the plant or unit specific loads connected. (Note: A representative mix of resistive and reactive loads is desired, but the exact proportions of each is not critical. However, testing assures that at least 712 KVARs are present.) Again, the connection of specific buses and loads is not necessary to verify the impact to these loads of the EDG response to a load rejection (EDG l-2A is tested at least once every 5 years by rejecting a load of 1200-2400 KW without exceeding the voltage limits specified. EDG IC is also tested at least once every 5 years by rejecting a load of 1200-2400 KW without exceeding die voltage limits specified). Therefore, each shared EDG on Unit I and Unit 2 meets this requirement.

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Conclusion* )

To minimize testing of the shared EDGs, the proposed TS change clarifies that testing of the shared EDG set on one unit may be used to satisfy SR 4.8.1.1.2.e requirements for both units. This is allowed since the j main purpose of the surveillance can be met by performing the test on either unit. The proposed testing '

validates that the EDGs function as required and do not subject plant loads to unacceptable transient, dynamie, and steady state ef9 cts due to generator output voltage and frequency. Therefore, this TS ch=ge ,

is acceptable.

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i Enclosure 2  :

i Joseph M. Farley Nuclear Plant  !

Emergency Diesel Generator Load Rejection Testing -

Technical Specification Changes j l

10 CFR 50.92 Evaluation i

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Enclosure 2 Joseph M. Farley Nuclear Plant Emergency Diesel Generator Load Rejection Testing Technical Specification Changes l

10 CFR 50.92 Evaluation .

Pursuant to 10 CFR 50.92, SNC has evaluated the proposed amerant.nte and has determined that operatice of the facility in accordance with the proposed amenk.cnts would not involve a significant

! - hazards consideration. The basis for this determination is as fsilows:

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l 1 l 1. He proposed changes do not involve a significant increase in the probability or consequences of an accident previously evaluated.

The proposed changes clarify that load rejection testing of the shared emergency diesel generator set is only required once per five years, and that testing of the shared EDG set on, one unit may be used to satisfy SR 4.8.1.1.2.e requirements for both units. These changes do not affect the probability or consequences of an accident. There are no changes being made to the emergency diesel generator testing program. These changes simply clarify the existing test program and the intent of the test requirements.

Therefore, the proposed TS changes do not involve a significant increase in the probability or l consequences of an accident previously evaluated.

2. The proposed changes do not create the possibility of a new or different kind of accident from any )

accident previously evaluated. I The proposed changes clarify that load rejection testing of the shared emergency diesel generator set is only required once per five years, and that testing of the shared EDG set on one unit may be used to satisfy SR 4.8.1.1.2.e requirements for both units. No new testing configuration is being proposed that could create the possibility of any new or differ.:nt kind of accident from any accident previously evaluated. There are no changes being made to the emergency diesel generator testing program. These changes simply clarify the existing test program and the intent of the test requirements.

Therefore, the proposed changes do not create the possibility of a new or different kind of accident from any accident previously evaluated.

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I Enclosure 2  ;

10CFR50.92 Evaluat!on .

3. The proposed changes do not involve a significant reduction in a margin of safety.

The proposed changes clarify that load rejection testing of the shared emergency diesel generator set is only required once per five years, and that testing of the shared EDG set on one unit may be used to satisfy SR 4.8.1.1.2.e requirements for both units. A similar technical specification change has been l previously approved by the NRC for Hatch Nuclear Plata. The technical specification bases and the t Final Safety Analysis Report have been reviewed. Clarification of the testing requirements has no  ;

effect on the margin of plant' safety since no reduct.on in the test program is involved.

Therefore, the proposed changes do not involve a sir,nificant reduction in a margin of safety.

Conclusion Based on the preceding analysis, SNC has determined that operation of Farley Nuclear Plant in accordance  ;

with the proposed change to the Technical Specificaticas will not significantly increase the probability or l consequences of an accident previously evaluated, create the possibility of a new or different kind of l accident from any accident previously evaluated, or involve a significant reduction in a margin of safety.

SNC therefore concludes that the proposed change meets the requirements of 10 CFR 50.92(c) and does not involve a significant hazards consideration.  ;

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Joseph M. Farley Nuclear Plant

! Emergency Diesel Generator Load Rejection Testing

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! Technical Specification Changes

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Unit 1 Technical Specification Paecs

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Changed Pages Page # Instnictions 3/4 8-2 Replace

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