ML20072C297
| ML20072C297 | |
| Person / Time | |
|---|---|
| Site: | Davis Besse  |
| Issue date: | 08/12/1994 |
| From: | Office of Nuclear Reactor Regulation |
| To: | |
| Shared Package | |
| ML20072C299 | List: |
| References | |
| NUDOCS 9408170172 | |
| Download: ML20072C297 (1) | |
Text
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Revised by NRC Ictter dated:
fugust 12, 1994 REFUELING OPERATIONS BASES 3/4.9.6 FUEL HANDLING BRIDGE OPERABILITY The OPERABILITY requirements of the hoist bridges used for movement of fuel i
assemblies ensures that:
1 fuel handling bridges will be used for movement of control rods and fuel ass)emblies, 2) each hoist has sufficient load capacity to lift a fuel element, and 3) the core internals and pressure vessel engaged during lifting operations. g force in the event they are inadvertently are protected from excessive liftin 3/4.9.7 CRANE TRAVEL - FUEL HANDLING BUILDING The restriction on movement of loads in excess of the nominal weight of a fuel assembly in a failed fuel container over other fuel assemblies in the storage pool ensures that in the event this load is dropped 1) the activity release will be limited to that contained in a single fuel as(sembly, and (2) any possible distortion of fuel in the storage racks will not result in a critical
. array. This assumption is consistent with the activity release assumed in the I accident analyses, i
' 3/4.9.8 COOLANT CIRCULATION
, The requirement that at least one decay heat removal loop be in operation ensures that (1) sufficient cooling capacity is available to remove decay heat and maintain the water in the reactor pressure vessel below 140*F as required during the REFUELING MODE, and (2) sufficient coolant circulation is maintained through the reactor core to minimize the effect of a boron dilution incident and prevent boron stratification.
The requirement to have two DHR loops OPERABLE when there is less than 23 feet of water above the core ensures that a single failure of the operating DHR
! loop will not result in a complete loss of decay heat removal capability.
With the reactor vessel head removed and 23 feet of water above the core, a large heat sink is available for core cooline.
Thus, in the event of a failureoftheoperatingDHRloop, adequate (imeisprovidedtoinitiate emergency procedures to cool the core.
In MODE 6, the RCS baron concentration is typically somewhat higher than the boron concentration required by Specification 3.9.1, and could be higher than the baron concentration of normal sources of water addition.
The flowrate through the decay heat system may at times be reduced to somewhat less than 2800 gpm.
In this situation, if water with a boron concentration equal to or greater than the boron concentration required by Specification 3.9.1 is added to the RCS, the RCS is assured to remain above the Specification 3.9.1 requirement, and a flowrate of less than 2800 gpm is not of concern.
3/4.9.9 CONTAINMENT PURGE AND EXHAUST ISOLATION SYSTE3 Deleted 1/_4.9.10 and 3/4.9.11 WATER LEVEL - REACTOR VESSEL AND STORAGE P00L i
The restrictions on minimum water level ensure that sufficient water depth is available to remove 99% of the assumed 10% iodine gap activity released from the rupture of an irradiated fuel assembly.
The minimum water depth is consistent with the assumptions of the safety analysis.
DAVIS-BESSE, UNIT 1 B 3/4 9-2 Amendment No. R, R 6,
.1M, 188 9408170172 940812 PDR ADOCK 05000346 P
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