ML20216F895

Proposed Tech Specs Re Fuel Storage Pool Water Level

ML20216F895
Person / Time
Site:	Maine Yankee
Issue date:	04/13/1998
From:	Maine Yankee
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ML20216F888	List: ML20216F883 ML20216F895
References
NUDOCS 9804170273
Download: ML20216F895 (6)

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• ATTACHMENT II PROPOSED CHANGE NO. 208 l ,

Maine Yankee Proposed Technical Specification Pages 3 3 I

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1 i 9804170273 900413 l PDR ADOCK 05000309 W ppR

Fuel Storage Pool Water Level 3.1.1 3.1 DEFUELED SYSTEMS 3.1.1 Fuel Storage Pool Water Level LCO 3.1.1 The fuel storage pool water level shall be 2 21 ft. over the top l of irradiated fuel assemblies seated in the storage racks.

APPLICABILITY: During movement of irradiated fuel assemblies in the fuel storage pool.

ACTIONS CONDITION REQUIRED ACTION COMPLETION TIME A. Fuel Storage pool water A.1 Suspend movement of Immediately level not within limit. Irradiated fuel assemblies in the fuel storage pool.

1 SURVEILLANCE REQUIREMENTS 4 SURVEILLANCE FREQUENCY l

SR 3.1.1.1 Verify the fuel storage pool water level is 2 21 ft 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> l above the top of irradiated fuel assemblies seated in l the storage racks.

I Maine Yankee 3-3 Amendment 464,

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l . ATTACHMENT III PROPOSED CHANGE NO. 208 l

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I Maine Yankee Proposed Technical Specification Basis Pages B 3.1 1 through B 3.1 3 l 1

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4 Fuel Storage Pool Water Level B 3.1.1 B 3.1 DEFUELED SYSTEMS B 3.1.1 Fuel Storage Pool Water Level BASES BACKGROUND The minimum water level in the fuel storage pool meets the assumptions of iodine decontamination factors following a fuel handling accident. The specified water level provides shielding during the movement of spent fuel and minimizes the general area dose.

A general description of the fuel storage pool design and the fuel storage pool cooling and purification system is giver' in the SAR. The assumptions of the fuel handling accident are given in the SAR.

APPLICABLE The Maine Yankee facility is permanently shutdown and the t me SAFETY ANALYSES since the last operation of the reactor has allowed significant decay of fission products (especially the daughter products with short half-lives) contained in the spent fuel. The spent fuel pool water level is adequate to provide necessary shielding for the fuel handlers to minimize occupational dose during normal spent fuel handling activities.

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The accident analysis for the fuel handling accident, as described in the l FSAR, assumes that the accident occurs one-year after shutdown from l operations and a decontamination factor for iodine of 75 (19 feet of I water.) No credit is taken for ventilation air filtration or isolation. For l the purpose of establishing an upper limit on the amount of fuel damage resulting from a fuel handling accident, it is assumed that the fuel assembly is dropped during handling. The number of ruptured fuel l rods which would result depends on several variables including the kinetic energy at impact and fuel assembly orientation during impact.

i The analyses indicate that if a fuel assembly were dropped to the bottom of the fuel storage pool and then rotated and struck a protruding structure, only the outer row of fuel rods would fail. However, to assure l

that the limiting case is considered, it is assumed that all rods in the dropped assembly fail upon impact. The resulting doses calculated for I the fuel handling accident are below the NRC acceptance limit for this l l accident, which is 10% of 10 CFR Part 100 limits. l j

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l Maine Yankee B 3.1-1 Amendment 4M, L

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Fuel Storage Pool Water Level B 3.1.1 BASES APPLICABLE The normal operating water level of the fuel storage pool is SAFETY ANALYSES established at approximately 36.5 (44 foot elevation) feet above the I (continued) floor of the pool. The Technical Specification value of 21 feet over the l top of irradiated fuel assemblies seated in the storage racks is equivalent to 34.7 feet of water above the fuel storage pool floor (42.2 l foot elevation). The top of the fuel assembly is defined as the bottom l of the flow plate, which is the top of the fuel rods. In the case of a fuel assembly dropped to the bottom of the fuel storage pool and standing ,

upright, the Technical Specification Water Level provides more than 19 l 1 feet of water for lodine decontamination. In the case of a fuel assembly l dropped and lying horizontally on top of the spent fuel racks, the l Technical Specification Water Level provides more than 19 feet of I water above the top of the bundle. l A reduction in margin of safety for the fuel handling accident occurs I when the acceptance limit (10% of 10 CFR Part 100 limite) is no longer l ,

met. The margin that exists between the technical specification limit for l the fuel storage pool water level and the fuel handling accident I acceptance limit represents operating margin. l ;

Radiological shielding analysis has determined that five-and-one-half l !

i feet of water above the top of a fuel assembly (bottom of the flow plate) l l raised to its maximum height maintains the radiation dose rates less I i

than 80 mrem /hr at the surface of the water and less than 50 mrem /hr l at the fuel handling hoist platform or the walkway around the pool. l Five-and-one-half feet of water above the top of a fuel assembly l l

(bottom of the flow plate) raised to its maximum height corresponds to l

an elevation of 42.0 feet (34.5 feet above the floor of the fuel storage l l

pool.) {

l A reduction in margin of safety for the radiological shielding analysis l .

! occurs when the acceptance limit is no longer met. The acceptance l l limit is defined as that combination of occupancy time and dose rate l such that no station personnel receive in excess of 5 rem per year (10 l CFR 20.1201). l (Continued) r Maine Yankee B 3.1-2 Amendment 464, l

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Fuel Storage Pool Water Level B 3.1.1 l BASES l LCO The fuel storage pool water level is required to be 2 21 ft. over the top l l of irradiated fuel assemblies seated in the storage racks. The specified

water level preserves the assumptions of the fuel handling accident l

analysis and provides shielding to minimize the general area dose when irradiated fuel is being moved. As such, it is the minimum level required for movement of irradiated fuel within the fuel storage pool.

l APPLICABILITY This LCO applies whenever irradiated fuel assemblies are being moved l in the spent fuel pool, since the potential for a release of fission

i. products exists and increased water level shielding is needed.

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ACTIONS M l

When the initial conditions for 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 i suspended. This effectively precludes a spent fuel handling accident l from occurring. This does not preclude movement of a fuel assembly to a safe position.

SURVElLLANCE SR 3.1.1.1

REQUIREMENTS This SR verifies sufficient fuel storage pool water is available in the l event of a fuel handling accident and to provide shielding to minimize l the general area dose during the movement of irradiated fuel. The water level in the spent fuel pool must be checked periodically when i moving fuel. The 24 hour2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> Frequency is appropriate because the l volume in the pool is normally stable. Water level changes are l controlled by facility procedures and are acceptable, based on 1 operating experience t

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l l Maine Yankee B 3.1-3 Amendment 464, l I

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