ML021300269
| ML021300269 | |
| Person / Time | |
|---|---|
| Site: | Byron  |
| Issue date: | 05/16/2002 |
| From: | Mahesh Chawla NRC/NRR/DLPM |
| To: | Office of Nuclear Reactor Regulation |
| References | |
| TAC MB4851, TAC MB4852, TAC MB4853, TAC MB4854 | |
| Download: ML021300269 (4) | |
Text
May 16, 2002 MEMORANDUM TO: Biweekly Notice Coordinator FROM: Mahesh Chawla, Project Manager, Section 2 /RA/
Project Directorate III Division of Licensing Project Management, NRR
SUBJECT:
REQUEST FOR PUBLICATION IN BIWEEKLY FR NOTICE -
NOTICE OF CONSIDERATION OF ISSUANCE OF AMENDMENTS TO FACILITY OPERATING LICENSES, PROPOSED NO SIGNIFICANT HAZARDS CONSIDERATION DETERMINATION, AND OPPORTUNITY FOR A HEARING (TAC NOS. MB4851, MB4852, MB4853, MB4854)
Exelon Generation Company, LLC, Docket Nos. STN 50-454 and STN 50-455, Byron Station, Unit Nos. 1 and 2, Ogle County, Illinois Docket Nos. STN 50-456 and STN 50-457, Braidwood Station, Unit Nos. 1 and 2, Will County, Illinois Date of amendment request: April 19, 2002 Description of amendment request: The proposed amendment would revise Technical Specification (TS) 3.6.6 surveillance requirement (SR) to verify each spray nozzle on the containment spray ring headers at the top of containment dome is unobstructed. The current TS 3.6.6.8 requirement is to verify each spray nozzle every 10 years. The proposed requirement is to revise the frequency to Following maintenance that could result in nozzle blockage OR Following fluid flow through the nozzles.
Basis for proposed no significant hazards consideration determination: As required by 10 CFR 50.91(a), the licensee has provided its analysis of the issue of no significant hazards consideration, which is presented below:
- 1. Does the proposed change involve a significant increase in the probability or consequences of an accident previously evaluated?
The proposed change revises the Frequency for Technical Specifications (TS)
Surveillance Requirement (SR) 3.6.6.8 for verifying each spray nozzle is unobstructed from "10 years" to "Following maintenance that could result in nozzle blockage OR Following fluid flow through the nozzles."
Analyzed events are initiated by the failure of plant structures, systems, or components. The Containment Spray (CS) system is not considered as an initiator of any analyzed event. The proposed change does not have a detrimental impact on the integrity of any plant structure, system, or component that initiates an analyzed event. No active or passive failure mechanisms that could lead to an accident are affected. The proposed change will not alter the operation of, or otherwise increase the failure probability of any plant equipment that initiates an analyzed accident. Therefore, the proposed change does not involve a significant increase in the probability of an accident previously evaluated.
The initial conditions of Design Basis Accident (DBA) and transient analyses in the Byron/Braidwood Stations UFSAR assume the CS system is operable. The operability of the CS system in accordance with the proposed TS is consistent with the initial assumptions of the accident analyses and is based upon meeting the design basis of the plant. Since plant safety can be ensured at the proposed Frequency, we are proposing to revise the CS system testing provisions to require nozzle testing only after activities that could result in nozzle blockage, i.e., following maintenance that could result in nozzle blockage or following fluid flow through the nozzles. Nozzle blockage is considered unlikely during periods without maintenance or without fluid flow through the nozzles, since the nozzles are of a passive design and the system is kept in a normally dry state, thus minimizing corrosion susceptibility. In addition, the location of the nozzles at the top of the containment dome limits the possibility of the introduction of foreign material from sources external to the CS system. The proposed Frequency will continue to provide confidence that an unobstructed flow path is available, and will preclude the need for unnecessary testing when no activities have occurred that would introduce debris to the spray ring headers, or when no other active degradation mechanism is present.
Operability of the CS system will not be affected. Therefore, the proposed change does not involve a significant increase in the consequences of an accident previously evaluated.
- 2. Does the proposed change create the possibility of a new or different kind of accident from any accident previously evaluated?
The proposed change does not involve the use or installation of new equipment.
Installed equipment is not operated in a new or different manner. No new or different system interactions are created, and no new processes are introduced.
The current foreign material exclusion practices have been reviewed and judged sufficient to provide high confidence that debris will not be introduced during times when the CS system boundary is breached. The design of the CS system at
Braidwood and Byron Stations precludes borated water from reaching the spray nozzles, except during a CS actuation. Therefore, the proposed change does not create the possibility of a new or different kind of accident from any accident previously evaluated.
- 3. Does the proposed change involve a significant reduction in a margin of safety?
The proposed change does not introduce any new setpoints at which protective or mitigative actions are initiated. No current setpoints are altered by this change. The design and functioning of the CS system is unchanged. Since the system is not susceptible to corrosion induced obstruction nor is the introduction of foreign material from external sources likely, and the design of the CS system at Braidwood and Byron Stations precludes borated water from reaching the spray nozzles except during a CS actuation, the proposed testing Frequency is sufficient to provide high confidence that the CS system will continue to function as designed. Therefore, the proposed change does not involve a significant reduction in a margin of safety.
Therefore, based on the above evaluation, we have concluded that the proposed change does not involve any significant hazards consideration.
The NRC staff has reviewed the licensees analysis and, based on this review, it appears that the three standards of 10 CFR 50.92(c) are satisfied. Therefore, the NRC staff proposes to determine that the requested amendments involve no significant hazards consideration.
Attorney for licensee: Edward J. Cullen, Deputy General Counsel, Exelon BSC - Legal, 2301 Market Street, Philadelphia, PA 19101 NRC Section Chief: Anthony J. Mendiola
Biweekly Notice Coordinator Braidwood and Byron Stations precludes borated water from reaching the spray nozzles, except during a CS actuation. Therefore, the proposed change does not create the possibility of a new or different kind of accident from any accident previously evaluated.
- 3. Does the proposed change involve a significant reduction in a margin of safety?
The proposed change does not introduce any new setpoints at which protective or mitigative actions are initiated. No current setpoints are altered by this change. The design and functioning of the CS system is unchanged. Since the system is not susceptible to corrosion induced obstruction nor is the introduction of foreign material from external sources likely, and the design of the CS system at Braidwood and Byron Stations precludes borated water from reaching the spray nozzles except during a CS actuation, the proposed testing Frequency is sufficient to provide high confidence that the CS system will continue to function as designed. Therefore, the proposed change does not involve a significant reduction in a margin of safety.
Therefore, based on the above evaluation, we have concluded that the proposed change does not involve any significant hazards consideration.
The NRC staff has reviewed the licensees analysis and, based on this review, it appears that the three standards of 10 CFR 50.92(c) are satisfied. Therefore, the NRC staff proposes to determine that the requested amendments involve no significant hazards consideration.
Attorney for licensee: Edward J. Cullen, Deputy General Counsel, Exelon BSC - Legal, 2301 Market Street, Philadelphia, PA 19101 NRC Section Chief: Anthony J. Mendiola DISTRIBUTION:
Non-Public PD3-2 r/f M. Chawla G. Dick C. Rosenberg ADAMS Accession Number: ML021300269 OFFICE PM:LPD3-2 PM:LPD3-2 LA:LPD3-2 SC:LPD3-2 NAME MChawla GDick /RA/ by MChawla CRosenberg AMendiola DATE 05/16/02 05/16/02 05/13/02 05/16/02 OFFICIAL RECORD COPY