ML14342A142
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McGuire Units 1 and 2 B 3.7.13-1 Revision No. 115 Spent Fuel Pool Water Level B 3.7.13 B 3.7 PLANT SYSTEMS B 3.7.13 Spent Fuel Pool Water Level BASES BACKGROUND The minimum water level in the spent fuel pool meets the assumptions of iodine decontamination factors following a fuel handling accident. The specified water level shields and minimizes the general area dose when the storage racks are filled to their maximum capacity. The water also provides shielding during the movement of spent fuel.
A general description of the spent fuel pool design is given in the UFSAR, Section 9.1.2 (Ref. 1). A description of the Spent Fuel Pool Cooling System is given in the UFSAR, Section 9.1.3 (Ref. 2). The assumptions of the fuel handling accident are given in the UFSAR, Section 15.7.4 (Ref. 3).
APPLICABLE The minimum water level in the spent fuel pool meets the assumptions of SAFETY ANALYSES the fuel handling accident described in Regulatory Guide 1.183 (Ref. 4).
The resultant 2 hour2.314815e-5 days <br />5.555556e-4 hours <br />3.306878e-6 weeks <br />7.61e-7 months <br /> TEDE dose per person at the exclusion area boundary is a small fraction of the 10 CFR 50.67 (Ref. 5) limits.
According to Reference 4, there is 23 ft of water between the top of the damaged fuel bundle and the fuel pool surface during a fuel handling accident. With 23 ft of water, the assumptions of Reference 4 can be used directly. In practice, this LCO preserves this assumption for the bulk of the fuel in the storage racks. In the case of a single bundle dropped and lying horizontally on top of the spent fuel racks, however, there may be < 23 ft of water above the top of the fuel bundle and the surface, indicated by the width of the bundle. To offset this small nonconservatism, the analysis assumes that all fuel rods fail, although analysis shows that only the first few rows fail from a hypothetical maximum drop.
The spent fuel pool water level satisfies Criterion 2 of 10 CFR 50.36 (Ref.
6).
LCO The spent fuel pool water level is required to be 23 ft over the top of irradiated fuel assemblies seated in the storage racks. The specified water level preserves the assumptions of the fuel handling accident analysis (Ref. 3). As such, it is the minimum required for fuel storage and movement within the spent fuel pool.
Spent Fuel Pool Water Level B 3.7.13 BASES McGuire Units 1 and 2 B 3.7.13-2 Revision No. 115 APPLICABILITY This LCO applies during movement of irradiated fuel assemblies in the spent fuel pool, since the potential for a release of fission products exists.
ACTIONS A.1 Required Action A.1 is modified by a Note indicating that LCO 3.0.3 does not apply.
When the initial conditions for prevention of an accident cannot be met, steps should be taken to preclude the accident from occurring. When the spent fuel pool water level is lower than the required level, the movement of irradiated fuel assemblies in the spent fuel pool is immediately suspended to a safe position. This action effectively precludes the occurrence of a fuel handling accident. This does not preclude movement of a fuel assembly to a safe position.
If moving irradiated fuel assemblies while in MODE 5 or 6, LCO 3.0.3 would not specify any action. If moving irradiated fuel assemblies while in MODES 1, 2, 3, and 4, the fuel movement is independent of reactor operations. Therefore, inability to suspend movement of irradiated fuel assemblies is not sufficient reason to require a reactor shutdown.
SURVEILLANCE SR 3.7.13.1 REQUIREMENTS This SR verifies sufficient spent fuel pool water is available in the event of a fuel handling accident. The water level in the spent fuel pool must be checked periodically. The Surveillance Frequency is based on operating experience, equipment reliability, and plant risk and is controlled under the Surveillance Frequency Control Program.
During refueling operations, the level in the spent fuel pool is in equilibrium with the refueling canal, and the level in the refueling canal is checked in accordance with SR 3.9.7.1.
Spent Fuel Pool Water Level B 3.7.13 BASES McGuire Units 1 and 2 B 3.7.13-3 Revision No. 115 REFERENCES
- 1.
UFSAR, Section 9.1.2.
- 2.
UFSAR, Section 9.1.3.
- 3.
UFSAR, Section 15.7.4.
- 4.
Regulatory Guide 1.183, Rev. 0.
- 5.
- 6.
10 CFR 50.36, Technical Specifications, (c)(2)(ii).