ML20203F706
| ML20203F706 | |
| Person / Time | |
|---|---|
| Site: | Hope Creek  |
| Issue date: | 02/09/1999 |
| From: | NRC (Affiliation Not Assigned) |
| To: | |
| Shared Package | |
| ML20203F700 | List: |
| References | |
| NUDOCS 9902180263 | |
| Download: ML20203F706 (5) | |
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- 4 UNITED STATES s
j NUCLEAR REGULATORY COMMISSION
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WASHINGTON, D.C. 200eNm01 SAFETY EVALUATION BY THE OFFICE OF NUCLEAR REACTOR REGULATION RELATED TO AMENDMENT NO.114TO FACILITY OPERATING LICENSE NO. NPF-57 PUBLIC SERVICE ELECTRIC & GAS COMPANY i
i ATLANTIC CITY Ft FCTRIC COMPANY HOPE CREEK GENERATING STATION DOCKET NO. 50-354 i
1.0 INTRODUCTION
By letter dated September 8,1998, as supplemented December 8,1998, the Public Service Electric & Gas Company (the licensee) submitted a request for changes to the Hope Creek Generating Station (HCGS), Appendix C," Additional Conditions." The requested changes would revise Appendix C, " Additional Conditions," and would allow the performance of single cell charging and the use of non-Class 1E single cell battery chargers, with proper electrical isolation, for charging connected cells in OPERABLE Class 1E batteries. The single cell chargers would be used to restore individual cell parameters to the normal limits specified in TS Table 4.8.2.1-1. Specifically, Appendix C would be revised to add the following additional license condition:
"The licensee is authorized to perform single cell charging of connected cells in OPERABLE class 1E batteries as described in the licensee's application dated i
September 8,1998, as supplemented by letter dated December 8,1998, and evaluated in the staff's safety evaluation attached to this amendment."
The December 8,1998, letter provided clarifying information that did not change the initial proposed no significant hazards consideration determination.
2.0 BACKGROUND
As described in the HCGS Updated Final Safety Analysis Report (UFSAR), Section 8.3.2, the Class 1E de system is designed to comply with General Design Criteria 17, and has sufficient capacity, capability, independence, redundancy, and testability to ensure the performance of its safety functions assuming a single failure.
The Class 1E de system distributes power at 125 V de and 250 V dc. The Class 1E 125 V de system is divided into four independent channel systems while the Class 1E 250 V de system is divided into two independent channel systems. The 125 V de system includes six batteries each consisting of 60 lead acid cells. The 250 V de system includes two batteries each 9902100263 990209 PDR ADOCK 05000354 P
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consisting of 120 lead acid cells. The 125 V de and 250 V de systems also include Class 1E battery chargers that are capable of supplying the largest combined demand of the various continuous steady-state loads plus the charging current to restore the capacities of the
. associated batteries.
4 Under normal operating conditions, the installed Class 1E battery chargers supply the i
operating de loads and a float charge to their respective batteries. The float voltage is the
' voltage applied to a battery to maintain it in a fully charged condition during normal operation.
. When the batteries are being float charged the normal 125 V de system voltage will be 132 to 135 V and the normal 250 V de system voltage will be 264 to 270 V.
t When an individual battery cell or a small number of cells exhibit low voltage or low specific gravity, the normal corrective action is to apply an equalizing charge to the entire battery. The equalizing charge (which is at a voltage higher than the float voltage) helps to correct l
inequalities that may develop in service among battery cells. When the batteries are being equalize charged, the 125 V de system voltage will be 140 V and the 250 V de system voltage will be 280 V. The 140 V and 280 V values are considered the maximum design operating voltages for the 125 V and 250 V de systems respectively.
Technical Specification (TS) 4.8.2.1 requires weekly surveillance of each designated pilot cell and quarterly surveillance of each connected cell of the Class 1E batteries to verify that the electrolyte level, float voltage, and specific gravity of the cells meet normal limits. The normal limits are specified in TS Table 4.8.2.1-1 and are designated as Category A (limits for each designated pilot cell) and Category B (limits for each connected cell). TS Table 4.8.2.1-1 also provides Allowable Values for electrolyte level, float voltage, and specific gravity for each connected cell. The Allowable Values are designated as Category C. With the parameters of one or more cells in one or more batteries not within normal limits (i.e., Category A, Category
. B), the battery is considered degraded but is still OPERABLE provided that the Cate0ory C Allowable Values are met. Operation with a battery cell's parameter outside the normallimits 1
but within the Allowable Value is permitted for up to 31 days before battery cell parameters
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must be restored to within normallimits.
The 31-day ACTION time was derived taking into consideration that, while battery capacity is degraded, sufficient capacity exists to perform the intended function while providing a time period adequate to permit full restoration of the battery cell parameters to normal limits.
As discussed above, when an individual battery cell or a small number of cells exhibit low voltage or low specific gravity, the normal corrective action is to apply an equalizing charge to l
the entire battery bank (i.e., via the use of the permanently installed Class 1E battery charger).
However, the effectiveness of an equalizing charge decreases when only a single cell or a small number of cells require equalizing. As stated in the Institute of Electrical and Electronics Engineers' Standard 450-1995, Section 4.4.2, " Equalizing Charge," single cell charging is an acceptable method of correcting low voltage or low specific gravity cell conditions.
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The proposed change would permit the use of non-Class 1E single cell battery chargers, with proper electricalisolation, for charging connected cells in OPERABLE Class 1E batteries. The single cell chargers would be used to restore individual cell parameters to the normal limits specified in TS Table 4.8.2.1-1, 3.0 EVALUATION The Nuclear Regulatory Commission (NRC) staff r6 viewed and evaluated the proposed performance of single cell charging and the use of non-Class 1 battery chargers as described below.
3.1 ' Performance of Sinole Cell Charoino The licensee's submittal dated September 8,1998, stated:
"An equalizing charge applied to the entire battery bank is the normal corrective action to restore the battery from a condition involving low cell voltage or low specific gravity. The effectiveness of an equalizing charge decreases when only a single cell or a small number of cells require equalizing. A more effective method of restoring the 5:;ticiy in that case is to perform single cell battery charging."
Single cell charging is an accepted industry practice to restore low cell voltage or low specific i
gravity. The staff finas the performance of single cell charging of single cells or a small number of cells in OPERABLE Class 1E batteries to be acceptable in order to restore individual cell parameters to the normal limits specified in TS Table 4.8.2.1-1.
3.2 Use of Non-Class 1E Battery Charoers The licensee requested that non-Class 1E battery chargers be used for performance of single cell charging of Class 1E batteries. The licenses submittats commit to the following equipment provisions and procedures with respect to the use of these battery chargers, a.
Eauipment (1)
At least two Class 1E properly rated fuses in series will be used on both the positive and negative leads between the battery charger and the cell (s) to protect the battery if a fault
. should develop in the charger. The fuses will be bolted to the frame of the battery charger. One set of the fuses will be used to connect the positive lead of the charger to the positive terminal of the battery cell and one set of fuses will be used to connect the negative lead of the charger to ther negative terminal of the battery cell.
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.(2)
The insulation of the charging cables between the charger and the cell will be rated 240V or greater. The voltage sensing leads between the charger and the cell will be #18 l_
or #20 AWG These leads will be non-Class 1E, however, the plant procedures will i
provide adequate as. urance that the leads or connecting clips will not cause a short circuit.
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(3)
Insulating material will be used to minimize the possibility of shorting leads or clips at the cell. The insulation of the matting which will be placed near the low voltage cell connections will be rated for a minimum of 1000V.
(4)
The charger design is such it will not be a load on the connected cell (s) in the event of loss of the charger input voltage or a short circuit in the 120 V ac source. The charger i
intemal design includes diodes and power transformer which will not allow current to flow from the de side to the ac side.
b.
Procedures (1)
Single cell charging will be limited to one OPERABLE Class 1E battery bank at a time.
Also single cell charging for an OPERABLE Class 1E battery will not be permitted if less i
than the minimum number of Class 1E batteries are OPERABLE as required by the TSs.
(2)
During single cell charging procedwJ controls will ensure the proper functioning of the charger. Monitoring will be performed at least once every eight hours.
(3)
Cells that have been charged using the single cell charging method will be checked weekly for four weeks after single cell charging. The increase of surveillance will ensure that the use of single ce!! charging will not cause long-term cell degradation to go undetected.
The staff reviewed the equipment provisions and procedures for the use of non-Class 1E battery chargers to perform single cell charging of Class 1E batteries. The licensee has provided adequate protection of the Class 1E battery from the non-Class 1E charger. In addition the licensee has included adequate procedures to implement the use of the non-Class 1E charger. Therefore, the staff finds the use of non-Class 1E battery chargers given the equipment provisions and procedures described above to be acceptable.
4.0 STATE CONSULTATION
in accordance with the Commission's regulations, the New Jersey State Official was notified of i
the proposed issuance of the amendment. The State official had no comments.
5.0 ENVIRONMENTAL CONSIDERATION
The amendment changes a requirement with respect to installation or use of a facility component located within the restricted area as defined in 10 CFR Part 20. 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 Commission has previously issued a proposed finding that the amendment involves no significant hazards consideration, and there has been no public comment on such finding (63 FR 53954). Accordingly, the amendment meets the eligibility criteria for categorical i
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exclusion set forth in 10 CFR 51.22(c)(9). Pursuant to 10 CFR 51.22(b) no environmental
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- impact statement or environmental assessment need be prepared in connection with the issuance of the amendment.
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6.0 CONCLUSION
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The Commission 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 I
operation in the proposed manner, (2) such activities will be conducted in compliance with the Commission's regulations, and (3) the issuance of the amendment will not be inimical to the common defense and security or to the health and safety of the public.
Principal Contributors: S. Saba R. Ennis Date: February 9, 1999 l