ML20198J958
| ML20198J958 | |
| Person / Time | |
|---|---|
| Site: | Davis Besse  |
| Issue date: | 10/16/1997 |
| From: | Jeffery Wood CENTERIOR ENERGY |
| To: | NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM) |
| References | |
| 2492, TAC-M97391, NUDOCS 9710220266 | |
| Download: ML20198J958 (10) | |
Text
. _ _ _
9 e
Ge w w t
$501 N State Route 2 -
41$ 249 2300 John K. Wood ook Hams,OH 43449 FA)(; 419-321-8331 -
Vce Proscert. Nucleaf ons s.se License Number NPF-3 Serial Number 2492 Docket Number 50 346 Oct.ober 16. 1997 United States Nuclear Regulatory Commission Document Control Desk Washington, D. C. 20555-0001'
Subject:
Second Response to Request for Additional Information Regarding the License Amendment Application to Revise Technical Specifications Regarding Electrical Systems (LAR 95-0021; TAC No. 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 (RAl) regarding the license amendment application. On August 19,1997, TE responded to the RAI (TE Serial Number 2481).
During subsequent telephone conversations with the NRC staff on September 29, October 1, October 8, and October 15,1997 the issues identified in the RAI were further explained, a new issue was identified and addressed, and additional information regarding the DBNPS surveillance test program for the station batteries was presented.- As agreed in these discussions and summarized in the enclosure,TE will submit a future License Amendment application to propose
- additional Technical Specification changes to address the issues identified by the NRC staff.
Based on this commitment, TE requests the continued processing and timely NRC approval of the License Amendment application submitted on October 28,1996.
5.. s0
~
9710220266 971016
" PJ' ignypppu N
ao"
- =
Docket Number 50446 License Number NPF Serial Number 2492 Page 2 Should you have any questions or require additional infonnation, please contact Mr. James L. Freels, Manager - Regulatory Affairs, at (419) 321-8466.
Very truly yours, MKUlaj Enclosure cc:
A. B. Beach, Regional Administrator, NRC Region 111 A. G. Ilansen, DB-1 NRC/NRR Project Manager S. Stasek, DB 1 NRC Senior Resident inspector J. R. Williams, Chief of Staff, Ohio Emergency Management Agency, State of Ohio (NRC Liaison)
Utility Radiological Safety Board
=..
s
- bocket Number 50-346
. License Number NPF-3 Serial Number 2492 Enclosure.
= SECOND RESPONSE TO Tile REQUEST FOR ADDITIONAL INFORMATION REGARDING LICENSE AMENDMENT REQUEST (LAR; 95-0021 FOR DAVIS BESSE NUCLEAR POWER STATION UNIT NUMBER 1 Attached 's Toledo Edison's second response (Toledo Edison letter Serial Number 2492) to the
- NRC letter dated June.,1997 (Toledo Edison Log Number 5086) requesting additional
- information rega' ding License Amendment Request 95-0021. The initial msponse was submitted r
by letter dated August 19,1997 (Toledo Edison Serial Number 2481). The Attachment also addresses an additional issue identified by the NRC staff during a subsequent telephone
- conversation on October 1,1997.
By:
J. K /'ood, Vicc President, uclear Sworn and Subscribed before me this 16th day of october, 1997.
rf w&
n Notary Public, Stafe of Ohio Nora Lynn Flood My Commission' expires September 4, 2002.
Docket Number 50 346 License Number NPF-3
- Serial Number 2492
- Attachment-Page 1.
SECOND RESPONSE TO Tile REQUEST FOR ADDITIONAL INFORMATION REGARDING LICENSE AMENDMENT REQUEST (LAR) 95-0021 FOR DAVIS BESSE NUCLEAR POWER STATION UNIT NUMBER 1
- NRC Reauest for Information:
1(1). Regarding Surveillance Requirement (SR) 4.8.2.3.2.e:
-(a)
Please explain how the battery discharge test will be perfenced 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 performed in lieu of the battery service test.
Does the performance discharge test envelop the battery service test?
Toledo Edison initial Response of Aucust 19.1997:
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 perfonn battery discharge testing while the plant is operating. Under a 24 month fuel cycle, battery discharge testing is planned to be performed during every other refueling outage, or approximately every four.
s.
The purpose of the proposed revision is to bring the SR into conformance with NRC Gene 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 perfonned 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 conduct of that surveillance.
With regards 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 the total ampere-hours discharged during the service test. In other words, the performimcc test is more challenging in terms of battery capacity, but the service test is more challenging in terms of voltage drop during the first minute high current demand.
- - + - -
Docket Number 50-346 License Number NPF-3 Serial Number 2492 Attachment Page 2 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, "lEEE 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 " modified" perfonnance test is a worst case load profile of the traditional service test and performance test combined.
Ilowever, the purpose of LAR 95-0021 is to propose changes pertinent to the increased operating cycle duration, consistent with the NRC's g.Mance in Generic Letter 91-04. Adoption of more current testing techniques is outside the scope of the proposed Licenre 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 improved " Standard Technical Specifications for Babcock and Wilcox Plants," as contained withia NUREG-1430 (ISTS). As stated in it's November 26,1996 letter to the NRC (TE Serial Number 2418), the DBNPS presently plans to submit a License Amendment Request relative to conversion to the ISTS in 1999.
Toledo Edison Second Resoonse:
Regarding the first part of the question, TE believes that the proposed change, re:noving the phrase "during shutdown" from the SR, is consistent with the NRC's recommendation in GL 91-04, llowever, should the NRC staff choose to not approve this portion of the License Amendment application, it would not impact the conversion of the DBNPS TS to a 24-month fuel cycle.
Regarding the second part of the question, TE notes that the last battery performance discharge tests were performed in the Fall of 1994 during the Ninth Refueling Outage (9RFO) for station batteries "2P" and "2N", and in the Spring of 1996 during 10RFO for station batteries "lP" and "lN". Hence, given the 60 month surveillance interval of SR 4.8.2.3.2.e, battery performance discharge testing is not due during the upcoming i!RFO, which is scheduled to commence in April,1998. The results of the last performance discharge tests for these batteries were as follows: 124.5% capacity for station battery "lP",121.1% capacity for station battery "IN",
118.9% capacity for station battery "2P", and 123.3% capacity for station battery "2N". The oldest of these batteries was installed in September,1986.
Considering the above, TE preposes to submit a separate License Amendment application for a change to SR 4.8.2.3.2.e to reflect the modified perfonnance discharge test described in IEEE Std. 450-1995 and NUREG-1430. This License Amendment application will be submitted by the end of 1998, which should allow ample time for NRC review and approval prior to the next scheduled performance of SR 4.8.2.3.2.e in the Spring of 2000 (12RFO), for station batteries
bocket Number 50-346 License Number NPF-3 Serial Number 2492 Attachment Page 3 "2P" and "2N". The additional time afforded for preparation and submittal of the application will also potentially allow the submittal to include pending NUREG-1430 changes presently under NRC review, in particular Technical Specification Task Force (TSTF) Standard Technical Specification Change Traveler Numbers 198 through 203.
NRC Request 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 "... previous performance test..." as per IEEE Standard 450, instead of
" average on previous performance tests...," as noted in your application?
Igledo Edison Response of Aucust 19.1997:
The existing SR 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), and is consistent with IEEE Std. 450-1980. Ilowever, 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 purpose of LAR 95-0021 is to propoce changes pertinent to the incr:ased 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, llowever, the DBNPS may consider the adoption of a later version of IEEE Std. 450 during the course of the conversion of the current DBNPS Technical Specifications to the ISTS.
Toledo Edison Second Response:
As previously noted, given the 60 month required surveillance interval for SR 4.8.2.3.2.c only service testing and no battery p:rformance discharge testing is scheduled during the upcoming iiRFO, which is scheduled to commence in April,1998. The oldest station batteries,"1P" and "lN", which were installed in September,1986, will not reach 85% of their service life until 12RFO. They will then need to be performance tested under the current SR 4.8.2.3.2.f, if they are not replaced.
Docket Number 50-346 License Number NPF-3 Serial Number 2492 Attachment i
Page 4 Toledo Edison proposes to include in the above-mentioned separate License Amendment application a proposed change to SR 4.8.2.3.2.f to reflect that the test criteria should be based on the most recent test rather than based on the average of previous testing. This is consistent w;th IEEE Std. 4501995 and NUREG-1430. As noted above, this License Amendment application will be submitted by the end of 1998. This should allow ample time for NRC review and approval prior to the next scheduled battery perfonnance testing in the Spring of 2000 (12RFO).
NRC Request for Informatios (3) Regarding Table 4.8-1:
(a) is the restriction on " level" in Footnote (a) necessary?
(b) is the restriction "...following a service or performance discharge test..." in Footnote (c) necessary?
Toledo Edison Response of Aucust 19.1997:
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 used 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 scope of the proposed License Amendment Request and beyond the current Licensing Basis. However, the DBNPS may consider the adoption of a later version of IEEE 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 deviations experierced 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 Std. 450-1980.
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 of less than L
l 4
Docket Number 50-346-License Number NPF 3 Serial Number 2492.
Attachment Page 5 2 amperes is an acceptable method to declare the battery fully recharged 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 e.harging 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 performance discharge test..." are necessary since they preclude use of the float charging current measurement in lieu of specific gravity measurement for the 7-day (SR 4.8.2.3.2.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.
Toledo Edison Second Resnonse:
Based on discussions with the NRC staff, although the NRC does not believe that the noted restrictions in footnotes (a) and (c) of TS Table 4.8-1 are necessary, the NRC does not require that TE revise these footnotes.
Toledo Edison plans to reevaluate this issue during preparation of the above-mentioned separate License Amendment application, and may include additional proposed changes in the scope of that applicatian,if warranted.
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 Resoonse of Aucust 19.1997:
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 calculation 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 l
" Docket Number 50-345 License Number NPF 3 Serial Number 2492 Attachment Page 6 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. Ilowever, the manufacturer-provided qualified service life of the current station batteries is actually a more conservative 16 years. Since a capacity test result of less than 80% (reference TS SR 4.8.2.3.2.e) is actually what indicates end of battery life, the reference to "20 year" life for aging consideration 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.
Toledo Edison Second Response:
The station batteries were initially sized to meet the original plant loads. Although " design margin" is not exphcitly included in the current battery sizing calculation, the plant modification process, which is conducted in accordance with DBNPS procedure NG EN-00301," Plant Modifications," ensures that any plant modification affecting battery capacity is evaluated to ensure that all DC design parameters are properly addressed. Further, a battery aging correction factor of 1.32 is used to accommodate a battery aged to 80% capacity and charged to 95%
capacity. This value corresponds to the operability criterion defined in the TS, which establishes that the battery is declared inoperable once it falls below SO% of rated capacity.
NRC Reauest for Information (as provided by telephone call on October 1.1997k (5) Regarding SR 4.8.2.3.2.f:
This SR presently states:
Every 18 months, during shutdown, performance discharge tests of battery capacity shall be given to any battery that shows signs of degradation or has reached 85% of the service life expected for the application. 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.
The October 28,1996 License Amendment application proposes to change the surveillance interval from "Every 18 months" to "Every REFUELING INTERVAL."
bocket Number 50-346 License Number NPF-3 Serial Number 2492 -
AttacInnent Page 7 Ilowever, the underlying purpose of this surveillance requirement is to increase the frequency of conducting performance discharge tests when the battery has reached 85% of its service life or when degradation is indicated. The proposed License Amendment would not increase this test frequency.
Toledo Edison Response:
Toledo Edison has reviewed this issue and concurs with the NRC staff's conclusion. In light of the underlying purpose of this surveillance requirement, should the NRC not approve this portion of the License Amendment,it would not impact the conversion of the DilNPS TS to a 24 month fuel cycle. This is because the surveillance requirement for an increased test frequency is only applicable after the battery performance has degraded (as defined in SR 4.8.2.3.2.f), or reached 85% of its service life. The oldest station batteries,"lP" and "lN", whicii were installed in Septembec,1986, will not reach 85% of their service life until 12RFO. They will then need to be performance tested under the current SR 4.8.2.3.2.f, if they are not replaced.
Toledo Edison will include proposed changes that would make the present SR 4.8.2.3.2.f consistent with the increased test frequency as specified in IEEE Standard 4501995 and NUREG 1430,in the scope of the above mentioned separate License Amendment application.
The proposed SR 4.8.2.3.2.f wouki read:
Except as noted below, an annual performance discharge or modified performance discharge test of battesy capacity shall be given to any battery that shows signs of degradation or has reached 85% of the service life expected for the application.
Degradation is indicated when the battery capacity drops more than 10% from its capacity on the previous performance discharge or modified performance discharge test, or is below 90% of the manufacturer's rating, if the battery has reached 85% of service life, delivers a capacity of 100% or greater of the manufacturer's rated capacity, and has shown no signs of degradation, performance testing at two year intervals is acceptable until the battery sho,vs signs of degradation.
--