ML20217N451

Forwards Response to Request for Addl Info Re 961028 Amend Application to Revise TS on Electrical Sys

ML20217N451
Person / Time
Site:	Davis Besse
Issue date:	08/19/1997
From:	Jeffery Wood CENTERIOR ENERGY
To:	NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
References
2481, TAC-M97391, NUDOCS 9708260174
Download: ML20217N451 (7)

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5501 N State Route 2 414249 2300 John K. Wood Oak HartxA oH 43449 FAX 4143214337 Vce Presdent Nuc ear oavis Beste License Number NPF-3 Docket Number 50 346 Serial Number 2191 -

August 19, 1997 .

United States Nuclear Regulatory Commission Document Control Desk l Washington, D. C. 20555-0001

Subject:

Response to Request for AdditionalInformation Regarding License Amendment Application to Revise Technical Specifications Regarding Electdcal Systems (LAR 95-0021; TAC Na, M97391)

Ladies and Gentlemen:

On October 28,1996, Toledo Edison (TE) submitted an application for an amendment to the Davis-Besse Nuclear Power Station (DBNPS), Unit Number 1, Operating License Number

- NPF-3, Appendix A Technical Specifications, regarding electrical systems for conversion to a 24 month fuel cycle (TE Serial Number 2403). On June 25,1997, TE received from the NRC (TE Log Number 5086) a request for additional information regarding the license arrendment application. Enclosed is a response to the request for additional information. I Should you have any questions or require additional information, please contact Mr. James L. Freels, Manager - Regulatory AfYairs, at (419) 321-8466.

-Very truly yours, l b ' Cl $$ y(h- ,;

n aj Enclosure cc: A. B. Beach, Regional Administrator, NRC Region III A. G. Hansen, DB-1 NRC/NRR Project Manager S. Stasek, DB-1 NRC Senior Resident Inspector 1..

J. R. Williams, Chiefof Staff, Ohio Emergency Management Agency, State of Ohio (NRC Liaison?

Utility Radioloyhl Safety Board

• ?708260174 970e19

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Docket Number 50-346 License Number NPF-3 Serial Number 2481 Enclosure RESPONSE TO REQUEST FOR ADDITIONAL INFORMATION REGARDING LICENSE AMENDMENT hEQUEST (LAR) 95-0021, FOR DAVIS-BESSE NUCLEAR POWER STATION UNIT NUMBER 1 This letter is submitted pursuant to 10 CFR 50.54 (f) . Attached is Toledo Edison's response (Letter Serial Number 2481) to the NRC letter dated June 25, 1997 (Toledo Edison Log Number 5086) requesting additional information regarding License Amendment Request 95-0021.

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By:  ! /1 #

T. J. Mye s or J. K. Wood, Vice President - Nuclear Sworn and Subscribed before me this 19th day of August, 1997.

L w Notary Public, St Nora Lynn Flood [e of Ohio My Commission expires September 3, 1997.

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Docket Number 50-346 License Number NPF-3

, Serial Number 2481

, Attachment

! Page1

( RESPONFE TO REQUEST FOR ADDI~IONAL INFORhiATION REGARDING LICENSE Ah1ENDhiENT REQUEST (LAR) 95-0021, FOR DAVIS BESSE NUCLEAR POWER STATION UNIT NUMBER 1 NRC Reouest for Information:

(1) Regarding Surveillance Requirement (SR) 4.8.2.3.2.e:

(a) Please explain how the battery discharge test will be performed once per 60 months while the unit is operating without going beyond the limits of the LCO (which requires restoration of the battery to operable status within 2 hours2.314815e-5 days <br />5.555556e-4 hours <br />3.306878e-6 weeks <br />7.61e-7 months <br />).

(b) This SR states: ,

Once per 60 month interval this performance discharge test may be perfc.rmed in lieu of the battery service test.

Does the performance discharge test envelop the battery service test?

Toledo Edhon Resnonse:

Although the proposed revision to SR 4.8.2.3.2.e removes the restriction to conduct performance discharge testing "during shutdown," the DBNPS does not plan to perform battery discharge testing while the plant is operating. Under a 24 month fuel cycle, performance discharge testing is planned to be performed during every other refueling outage, or approximately every four years. The purpose of the proposed revision is to bring the SR mto conformance with NRC i Generic Letter (GL) 91-04, " Changes in Technical Specification Surveillance Intervals to Accommodate a 24-Month Fuel Cycle," dated April 2,1991, wherein the NRC Staff concluded that the TS need not restrict surveillances as only being performed during shutdown, and that licensees are to give proper regard for performing refueling interval surveillances during power operation or during another mode that is consistent with the safe cont et of that surveillance.

With regard to the second part of the question, the performance test load profile does not completely envelop the service test load profile, in particular during the first minute of the service test load profile. Ilowever, the total ampere-hours discharged during the performance test exceeds th total ampere-hours discharged during the service test. In other words, the

, Docket Number 50 346 License Number NPF 3

'Se4ial Number 2481

. Attachment Page2 performance test is more thallenging in terms of battery capacity, but the service test is more challenging in terms of voltage drop during the first minute high current demand.

As stated in TS Bases 3/4.8, the Surveillance Requirements for demonstrating OPERABILITY of the station batteries are based on the recommendations of Regulatory Guide 1.129,

" Maintenance Testing and Replacement of Large Lead Storage Batteries for Nuclear Power Plants,' February 1978, and IEEE Std. 450-1980,"IEEE Recommended Practice for Maintenance, Testing, and Replacement of Large Lead Storage Batteries for Generating Stations and Substations." The DBNPS is aware that the more recent IEEE Std. 450-1995 discusses a

" modified" performance test which would envelop the load profile of the service test. This

" mod:fied" performance test is a worst case load profile of the traditional service test and performance test combined.

However, the purpose of LAR 95-0021 is to propose changes pertinent to the increased operating cycle duration, consistent with the NRC's guidance in Generic Letter 91-04. Adoption of more current testing techniques is outside the scope of the proposed License Amendment Request and beyond the current Licensin Basis. However, the DBNPS may consider the adoption of a later version ofIEEE Std. 450 during the course of the conversion of the current DBNPS Technical Specifications to the improved " Standard Technical Specifications for Babcock and Wilcox Plants," as contained within NUREG-1430 (ISTS). As stated in it's November 26,1996 letter to the NRC (TE Serial Number 2418), the DBNPS presently plana to submit a License Amendment Request relative to conversion to the ISTS in 1999.

N"J Reauest for Information:

(2) Regarding SR 4.8.2.3.2.f:

This SR states:

Degradation is indicated when the battery capacity drops more than 10% of rated capacity from its average on previous performance tests, or is below 90%

of the manufacturer's rating.

Should this read "...previc i performance test..." as per IEEE Standard 450, instead of

"... average on previous perb u nce tests...," as noted in your application?

Toledo Edison Resnonse:

The existing SR was added to the DBNPS TS via License Amendment No.100 dated March 12,1987, based on by model Technical Specifications for station batteries guidance provided by the NRC to Toledo Edison (TE Log Number 756, dated July 16,1981), and is e ,

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, Docket Number 50 346 License Number NPF 3 t . Serial Number 2481 l . Attachment l Page 3 I

consistent with IEEE Std. 430-1980, llowever, the more recent IEEE Std. 450-1995 bases the degradation determination only on the most recent test, rather than the average of previous tests.

As noted above, the purpcm of LAR 95-0021 is to propose changes pertinent to the increased operating cycle duration, consistent with the NRC's guidance in Generic Letter 91-04. Adoption of more current testing requirements is outside the scope of the proposed License Amendment Request and beyond the current Licensing Basis. However, the DBNPS may consider the adoption of a later version ofIEEE Std. 450 during the course of the conversion of the current DBNPS Technical Specifications to the ISTS.

NRC Reouest for information:

(3) Regarding Table 4.8-1:

(a) Is the restriction on " level" in F. atnote (a) necessary?

(b) Is the restriction "...following a service or performance discharge test..." in Footnote (c) necessary?

Toledo Edison Response:

Technical Specification Table 4.8 1, including current Footnote (a), was added to the DBNPS TS via License Amendment No.100 dated March 12,1987, based on the model Technical Specifications for station batteries guidance provided by the NRC to Toledo Edison (TE Log Number 756, dated July 16,1981). Although the Footnote (a) correction of the specific gravity parameter for electrolyte level is not required in the more recent IEEE Std. 450-1995, the purpose of LAR 95-0021 is to propose changes pertinent to the increased operating cycle duration, consistent with the NRC's guidance in Generic Letter 91-04. As indicated above, adoption of more current testing requirements is outside the :. cope of the proposed License Amendment Request and beyond the current Licensing Basis. However, the DBNPS may consider the adoption of a later version ofIEEE Std. 450 during the course of the conversion of the current DBNPS Technical Specifications to the ISTS.

Footnote (c) to TS Table 4.8-1, " Battery Surveillance Requirements," was added via License Amendment No.158 dated July 16,1991, in response to the Toledo Edison license amendment application dated March 1,1991 (TE Serial Number 1898). This footnote adds exceptions to the specific gravity requirements. As stated in the portion of TS Bases 3/4.8 also added via License Amendment 158, the exceptions to the specific gravity requirements are taken to allow for the normal devie. ions experienced after a battery discharge and subsequent recharge associated with a service or performance discharge test, and the specific gravity deviations are recognized and discussed in IEEE Stu. 450-1980.

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[ Docket Number 50-346 License Number NPF-3 SerialNumber 248!

, Attachment Page 4 ,

As further described in the March 1,1991 license amendment application and in the NRC Safety Evaluation accompanying License Amendment No.158, a float charging current ofless than 2 amperes is an acceptable method to declare the battery operable after a discharge test; other battery parameters, i.e., specific gravity, take longer to stabilize and cannot provide an immediate and an accurate determination of state-of-charge. In addition, data has shown that battery charging current responds more quickly than specific gravity readings to changes in the state-of-charge. Therefore, using charging current to determine the state-of-charge of the battery following a discharge test reduces the amount of time required to declare a battery operable. The March 1,1991 license amendment application was requested to allow for a potential reduction of critical path duration during a refueling outage.

The words "...following a service or performano discharge test..." are necessary since they preclude use of the float charging current measuremen: in lieu of specific gravity measurement for the 7-day (SR e. 8.2.3.2.a.1) and 92-day (SR 4.8.2.3.2.b.1) surveillance tests, when the {

specific gravity would reasonably be expected to be stable and capable of providing an immediate and accurate determination of state-of-charge.

NRC Reauest for information:

(4) Regarding Enclosure 3, Page 3:

The second paragraph indicates that the sizing of the batteries includes approximately 20%

overcapacity to compensate for loss due to aging of batteries over a 20-year period. Please provide details on how this conclusion was reached.

Toledo Edison Response:

Section 8.3.2.1.2 of the DBNPS Updated Safety Analysis Report (USAR) describes the station batteries and cites the referenced statement regarding sizing of the batteries. USAR Section 8.3.2.1.2 also includes a detailed load list for each battery, taken from DBNPS Calculation C-EE-002.01-010. The calculatior. shows that the battery is adequately sized to accommodate anticipated aging degradation to 80% of rated capacity, while still being capable of performing its safety function. The calculation utilizes an aging factor of 1.32 for cell sizing, which includes the 1.25 aging factor recommended in IEEE Std. 485-1983," Recommended Practice for Sizing Large Lead Storage Batteries for Generating Stations and Substations," plus additional conservatism to compensate for a battery charged to only 95% of capacity (1.25 x 100%/95% = ,

1.32).

The "20 year period" refers to the design life of the current station batteries. However, the manufacturer-provided qualified service life of the current station batteries is actually a more conservative 16 years. Since a capacity test result ofless than 80% (reference TS SR 4.8.2.3.2.e)

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Docket Number 50-346 License Number NPF-3 Serial Number 2481

. Attachment Page 5 is actually what indicates end of battery life, the reference to "20 year" life for aging considra*. ion does not have any correlation to a Technical Specification requirement. Technical Specification SR 4.8.2.3.2.f requires that performance discharge tests of battery capacity be given to any battery that shows signs of degradation or has reached 85% of the service life expected for the application. Since 16 years is the service life expected, this SR is required to be performed at 85% of 16 years, or 13.6 years from installation.

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