ML20213E800
| ML20213E800 | |
| Person / Time | |
|---|---|
| Site: | Brunswick  |
| Issue date: | 11/07/1986 |
| From: | Cutter A CAROLINA POWER & LIGHT CO. |
| To: | Muller D Office of Nuclear Reactor Regulation |
| Shared Package | |
| ML20213E802 | List: |
| References | |
| NLS-86-337, NUDOCS 8611130292 | |
| Download: ML20213E800 (4) | |
Text
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CD&L CaroHna Power & Light Company SERIAL: NLS-86-337 NOV 7 36 86TSBt4 Director of Nuclear Reactor Regulation Attention:
Mr. Dan Muller, Director BWR Project Directorate #2 Division of BWR Licensing United States Nuclear Regulatory Commission Washington, DC 20555 BRUNSWICK STEAM ELECTRIC PLANT, UNIT NOS.1 AND 2 DOCKET NOS. 50-325 & 50-324/ LICENSE NOS. DPR-71 & DPR-62 REQUEST FOR LICENSE AMENDMENT D. C. DISTRIBUTION SYSTEM
Dear Sir:
SUMMARY
In accordance with the Code of Federal Regulations, Title 10, Parts 50.90 and 2.101, Carolina Power & Light Company (CP&L) hereby requests a revision to the Technical Specifications (TS) for the Brunswick Steam Electric Plant (BSEP), Unit Nos. I and 2.
The proposed change revises Surveillance Requirement 4.8.2.3.l(b), deleting specific reference to 37.5 KVA power conversion modules and more clearly defining acceptable loading of the B division battery bus. The modification discussed below effects both the A and B division batteries. However, since the Technical Specifications address only the B division batteries, only the effect to that division is addressed by this submittal. The modification was also reviewed per 10 CFR 50.59 for its impact on the A division batteries.
DISCUSSION The B division battery bus for each of the Brunswick units is configured such that it is the normal feed for a unit's lighting inverter and standby Uninterruptible Power Supply (UPS). In addition, the B division bus serves as the alternate feed for the opposite unit's lighting inverter. Each of the lighting inverters and the power conversion module for the UPS is currently rated at 37.5 KVA.
In 1984, CP&L completed a detailed DC Battery Load Study for BSEP. This study evaluated the actual sequential loading of the batteries during the design basis event.
The design basis event assumed for the study is a loss of offsite power coincident with a large and/or small break loss of coolant accident on one unit and an orderly safe shutdown of the other unit. One assumption of the study is that no more than two of the possible three 37.5 KVA power conversion modules can be aligned to the B division bus at at any time. The actual loading of the power conversion modules were determined and the combination which placed the greatest load on the battery system was used for the Load Study. The largest load on the battery occurs when two lighting inverters are aligned to the B division bus.
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Director of Nuclear Reactor Regulation NLS-86-337 / Page 2 In an effort to ensure that no more than two of the 37.5 KVA power conversion modules are aligned to the B division bus at any time, the Company incorporated Surveillance Requirement 4.8.2.3.l(b) into the BSEP Technical Specifications. This surveillance requirement currently requires verification at least once per seven days that there are no more than two 37.5 KVA power conversion modules aligned to the B division bus.
In addition to amending the Technical Specifications as indicated, provisions for 3
evaluating any change which could affect the Battery Load Study were incorporated into BSEP Procedure ENP-03. Section 4.3.3 of this procedure states in part:
An evaluation shall be performed to assess the effects of the modification on the 125/250 VDC Electrical Distribution System and the DC Battery Load Study (9527-FP-81457). The review shall determine if the modification:
Adds, changes, or deletes any DC loads.
Changes the starting, stopping, or cycling intervals or frequency (load sequencing) of existing DC loads.
1 Changes the design basis or assumptions for the report on battery loading for loss of off-site power coincident with large break LOCA/small break LOCA (Report No. 7579-139-S-E-002, FP 9527-FP-81457), also known as the DC Battery Load Study.
This evaluation is done in accordance with the provisions of 10 CFR 50.59.
The UPS system is a Non-lE system which feeds various loads throughout the Brunswick Plant, including equipment located in the electronic equipment room, the computer room, and the filter house. The existing UPS system is approaching obsolescence and is considered to be beyond reasonable maintainability. Therefore, the plant intends to replace the existing 37.5 KVA UPS system, which includes a primary power converter unit, a standby power converter unit, and a switching module with new equipment rated at 50 KVA and with the same functional capabilities. The UPS system modification is currently scheduled to be completed on Unit No. I during the upcoming refueling
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outage. A similar modification for Unit No. 2 is expected during a future outage.
In accordance with the plant procedure discussed above, the proposed modification of the UPS System was evaluated for its impact on the DC Battery Load Study. The loads fed from the UPS power conversion module are not altered by this modification. However, 3
there is a slight increase in the load to the batteries due to a decrease in the efficiency of the new 50 KVA system. The efficiency of the existing 37.5 KVA UPS is 89.2 percent.
4 The efficiency of the proposed new 50 KVA UPS is 76 percent. This difference in efficiency results in a net additional load to the batteries of approximately 20 amps.
Even with the additional 20 amps, due to the new UPS, the configuration of two lighting inverters is still the most conservative loading of the B division bus. Therefore, the proposed modification has no impact on the results of the Battery Load Study. The capacity margin of the batteries is unaffected.
As a result of the upgrade of the UPS as described above, Surveillance Requirement 4.8.2.3.l(b) is revised to delete reference to 37.5 KVA power conversion modules and to I
more clearly define the acceptable configurations. The surveillance requirement is rewritten to encompass both the 37.5 KVA modules associated with the lighting inverters i
and the 50 KVA modules associated with the UPS.
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Director of Nuclear Reactor Regulation NLS-86-337 / Page 3 SIGNIFICANT HAZARDS ANALYSIS The Commission has provided standards in 10 CFR 50.92(c) for determining whether a significant hazards consideration exists. A proposed amendment to an operating license for a facility involves no significant hazards consideration if operation of the facility in accordance with the proposed amendment would not: (1) involve a significant increase in the probability or consequences of an accident previously evaluated;(2) create the possibility of a new or different kind of accident from any accident previously evaluated; or (3) involve a significant reduction in a margin of safety. CP&L has reviewed this request and determined that:
1.
The proposed amendment does not involve a significant increase in the probability or consequences of an accident previously evaluated. The 37.5 KVA power conversion modules of the Uninterruptible Power Supply are being replaced with functionally equivalent equipment. The UPS is not a safety-related system. However, the bus which fecas the UPS also feeds safety-related equipment. A fault on the UPS system would not adversely atfect the safety-related equipment. Each system on the bus is equipped with its own breaker such that a fault on that system would isolate the system from the bus, thereby, prohibiting interaction with other systems on the bus. As stated above, the capacity of the batteries to function as required in an accident situation is unaffected by this change. Although the load on the battery with the 50 KVA UPS would be slightly increased (~20A), the combination of two lighting inverters on the B division bus continues to be the most conservative loading. Therefore, the design basis event for the Battery Load Study is unaffected by this change.
2.
The proposed amendment does not create the possibility of a new or different kind of accident from any accident previously evaluated because the function and capabilities of the UPS will not change significantly. The 37.5 KVA power conversion modules are being replaced with functionally equivalent 50 KVA equipment. Deleting reference to the rating (i.e.,37.5 KVA) of the power conversion modules does not create the possibility of additional loading of the B division batteries. Plant Procedure ENP-03 prohibits any modification to the battery load without prior evaluation of the impact on the Battery Load Study in accordance with 10 CFR 50.59.
3.
The proposed amendment does not involve a significant reduction in a margin of safety. As stated above, the additional load on the existing 125/250 volt B division batteries due to the reduced efficiency factor of the larger UPS conversion modules has been evaluated and determined not to af fect the capacity margin of the battery system. The combination of two lighting inverters continues to be the most conservative load on the B division batteries.
Based on the above reawning, CP&L has determined that the proposed amendment does not involve a significant hazards consideration.
ADMINISTR ATIVE INFORM ATION The revised Brunswick Technical Specification pages are provided in Enclosures 1 and 2.
The Company has evaluated this request in accordance with the provisions of 10 CFR 170.12 and determined that a license amendment application fee is required. A check for $l50 is enclosed in payment of this fee. Issuance of this amendment is requested by April 22,1987, in order to support restart of Brunswick-1.
Director of Nuclear Reactor Regulation NL5-86-337 / Page 4 f
Carolina Power & Light Company has evaluated this request in accordance with the j
provisions of 10 CFR 170.12 and determined that a license amendment application fee is j
required. A check for $150 is enclosed in payment of this fee.
Please refer any questions regarding this submittal to Mr. Sherwood R. Zimmerman at 1
(919) 836-6242.
Yours very trul,
$d h A. B. Cutter - Vice sident 4
Nuclear Engineering & Licensing ABC/RWS/bmc (4077RWS)
Enclosures
- cc: Mr. W. H. Ruland (NRC-BNP)
Dr. 3. Nelson Grace (NRC-Ril)
Mr. E. Sylvester (NRC)
Mr. Dayne H. Brown
- All With Enclosures 1 and 2 1
A. B. Cutter, having been first duly sworn, did depose and say that the information contained herein is true and correct to the best of his information, knowledge and belief; and the sources of his information are officers, employees, contractors, and agents of Carolina Power & Light Company.
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