ML20202E578
| ML20202E578 | |
| Person / Time | |
|---|---|
| Site: | Byron  |
| Issue date: | 11/25/1997 |
| From: | NRC (Affiliation Not Assigned) |
| To: | |
| Shared Package | |
| ML20202E576 | List: |
| References | |
| NUDOCS 9712080083 | |
| Download: ML20202E578 (3) | |
Text
tag O"
- e UNITED STATES g
,g NUCLEAR REGULATORY COMMISSION WASHINGTON, D.C. 2066H001 o
.....,o SAFETY EVALUATION BY THE OFFICE OF NUCLEAR REACTOR REGULATION RELATED TO AMENDMENT NO. 93 TO FACILITY OPERATING LICENSE NO. NPF-37 AND AMENDMENT NO. 93 TO FACILITY OPERATING LICENSE NO. NPF-66 COMMONWEALTH EDISON COMPANY BYRON STATION. UNIT NOS.1 AND 2 DOCKET NOS STN 50-454 AND STN 50-455
1.0 INTRODUCTION
By letter dated April 7,1997, as supplemented on August 7,1997, Commonwealth Edison Company (Comed, the licensee), proposed to amend Appendix A, Technical Specifications (TS) of Facility Operating Licenses NPF-37 and NPF-66 for Byron Nuclear Power Station, Units 1 and 2.
Comed proposed to revise Section 3/4.8.2, D.C. Sources and its Bases Section of the TS to allow the replacement of the existing installed 125 volt de Gould Batteries, which are nearing 85 percent of qualified life, with new 125 volt de C&D Charter Power Systems, Inc. (C&D) batteries, in addition, the licensee proposed to revise the crosstie limitation to reflect the increased capacity of the C&D replacement batteries.
2.0 BACKGROUND
The existing Gould batteries at Byron were installed in 1979. Comed plans to replace these batteries with new 125 volt de C&D cells during upcoming refueling outages because the Gould cells are near 85 percent of their 20 years qualified life. In Amendment No. 59, the NRC approved changes to allow the installation of Lucent Technologies (AT&T) round cell batteries to iplace the Gould batteries. However, the round cells were not installed at Byron due to the problems of loss of capacity of the high specific gravity (1,300) round cells at Braidwood, Palo Verde and McGuire nuclear power plants. As a result, Comed decided to use C&D batteries instead of AT&T batteries and proposed changes to the Byron TS to reflect the installation of the C&D batteries. Corresponding changes are also being proposed by the licensee for the improved Technical Specifications, which are currently in the review process by the NRC staff.
3.0 EVALUATION During the review of Comed's request, the staff identified the need for further information and issued a Request for Additional Information (RAI) dated June 20,1997.
The RAI covered subjects related to specific gravity, charging current, performance and service tests, aging and design margin factors used in sizing the C&D batteries and the results of the last performance test of the Gould batteries to assess the battery degradation. By letter dated August 7,1997, Comed provided the answers to the questions raised in the RAI and revised their proposed TS changes. The proposed changes are:
9712090003 971125 PDR ADOCK 05000454 P
1 (1)
All references to AT&T batteries are deleted since these will not be instal;ed. These include load restrictions provisions of TS 3.8.2.1, Action c.1 and 3.8.2.2 Action b.1, along with Table 4.8.2 (AT&T Battery Surveillance Requirements). AT&T references are also removed from Surveillance Requirements (SRs) 4.8.2.1.2.a.2,4.8.2.1.2.e,4.8.2.1.2.f, footnote to 4.8.2.1.2.b.2,4.8.2.1.2.c.3 and the TS Bases.
(2)
Surveillance Requirement 4.8.2.1.2.a.2 adds the total battery terminal float voltage to be 2127.6 nits for the C&f, battery. This is the minimum recommended value for the total battery float charge voltage range of 2.20 to 2.25 volts per cell. C&D has stated that for the optimum battery life, the float voltage should be at a value that results in positive plate polarizations between 50 and 100 millivolts above open circuit. In C&D lead calcium alloy batteries of LCUN-33 design, this occurs at a float charge between 2.20 and 2.25 volts per cell. The terminal voltage of 2127.6 volts ensures the effecilveness of the battery charger to float charge the battery and to maintain the battery in a fully charged state.
(3) in order to comply with IEEE-450,
- Recommended Practice for Maintenance, Testing, and Replacement or Vented Lead-Acid Batteries for Stationary Applications," and the proposed improved Technical Specifications as they apply to the new batteries, Comed revised SR 4.8.2.1.2.f and SR 3.8.4.4 to perform a performance test or modified performance test at least once per 12 months during shutdown, instead of 18 months for any battery that shows signs of degradation or has reached 85 percent of its qualified service life. Additionally, the Note in SR 3.8.4.3, SR 3.8.4.4 and the Bases for the same are being revised to allow the modified performance test to be performed in lieu of either the normal performance test or the aervice test for the C&D batteries. Surveillance Requirement 4.8.2.1.2.g has been added in order to retain the currant 18 month testing requirements for the Gould battery 111 until entering MODE 4 for Unit 1, Cycle 9. This battery's capacity essentially did not change in 5 years and the results of performance tests of this Gould battery shows that the battery capacity is near the manufacturer's ratec' capacity. Additionally, the Gould batteries are being replaced during the next refueling outage. The above changes comply with IEEE-450.
(4)
Table 4.8.2 (Battery Surveillance Requirements) is being revised so that it applies to both the Gould and C&D batteries. First, a table notation will be revised to state that the manufacturer recommended charging current for the battery is less than 3 amps for the C&D battery. Second, the Table will be revised because C&D recommends correcting for electrolyte temperature for C&D batteries, not for level. Both IEEE-450 and C&D's operating instruotions do not recommend correcting electrolyte specific gravity values for level, but for temperature only. However, Gould operating instructions recommend temperature and level correction. Cince Gould batteries are to be replaced in the next refueling outage, Comed is not requesting changes to Gould battery level corrections.
Table 4.8.2 will be modified to reflect the different operating instructions for C&D and Gould batteries.
(5)
The crosstie provisions, T.S. 3.8.2.1, Action c.1 and 3.8.2.2, Action b.1 provide a load restriction while the battery is crosstied to opposite unit. The limit ensures that the operable battery has the capacity to energize the design basis load of its DC bus while maintaining the limited DC loads of ine inoperable DC bus on the shutdown unit. The proposed crosstie loading limit of 200 ampere reflect the larger capacity of the C&D batteries.
- _ _ ~ _ _ _ _ _. _. _ _ _ _ _ _ _ _
I 3-(6)
The editorial change in 3.8.2.2, Action b (1), 'Opposita Bus' is changed to " Opposite Unit' and is conslatent with Specification 3.8.2.1, Action c (1).
(7)
Comed confirmed in their letter of August 7,1997, that the C&D batteries were sized using an aging factor of 1.25 and a design margin of 10 percent, Comed, in their letter of April 7,1997, states that the C# D batteries meet or exceed the design, functional and qualification requirements of the installed Gould batteries. Using the C&D batteries will not impact the function of the DC system.
4.0
SUMMARY
The C&D batteries are similar in design to the existing installed Gould batteries, are qua9fied for 20 years, and have a significant larger capacity which can provide additional margin.
Additionally, the short circuit current provided by the C&D batteries are within the intermpting capabilities of the existing DC system circuit breakets. After a review of the changes prop',ted by the licensee, the staff concludes that the changes are consistent with manufacturer recommendations and current industry standards (i.e., IEEE-450).
5.0 STATE CONSULTATION
in accordance with the Commission's regulations, the lilinois State official was notified of the proposed issuance of the amendments. The State official had no comments.
6.0 ENVIRONMENTAL CONSIDERATION
The amendments change a requirement with respect to the installation or use of a facility component located within the restricted area as defined in 10 CFR Pstt 20 and change 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 has been no public comment on such finding (62 FR 54868). 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 environmental impact statement or environmental assessment need be prepared in connection with the issuance of the amendments.
7.0 CONCt.USION The Commission has concluded, based on the considerations discussed above, that: (i) 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 ir.suance of the amendments will not be inimical to the common defense and security or to the health and safety of the public.
Principai Centributor: S. Saba Date: November 25,1997
_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ - _ _ _ _ _ _ - _ _ _ _ _ _