ML20136J550

Proposed Tech Specs Rev for Section 3.10, Core Alterations Allowing Removal of Suspect Fuel Bundles Out of Planned Sequence

ML20136J550
Person / Time
Site:	Pilgrim
Issue date:	03/07/1997
From:	BOSTON EDISON CO.
To:
Shared Package
ML20136J533	List: ML20136J527 ML20136J550
References
NUDOCS 9703200138
Download: ML20136J550 (1)

Text

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j BASES:

, ' 3.10 CORE ALTERATIONS (Cont) I B. . Core.Monitorino The source range monitors (SRMs) are provided to monitor the core during periods of station shutdown and to guide the operator during refueling operations and station startup. Requiring two operable SRMs in or adjacent to any core quadrant where fuel or control rods are being moved ensures adequate monitoring of that quadrant during such alterations. The requirement of 3 counts per second (cps) provides assurance that neutron flux is being monitored and ensures startup is conducted only if the source range flux level is above the minimum assumed in the control rod drop accident.

The limiting conditions for operation of the SRM subsystem of the neutron monitoring system are derived from the Station Nuclear Safety Operational Analysis (FSAR I Appendix G) and a functional analysis of the neutron monitoring system. The i specification is based on the Nuclear Safety Requirements for Plant Operation in Subsection 7.5.10 of the FSAR.

A spiral unloading program is one by which the fuel in the outermost cells (four fuel bundles surrounding a control blade)is removed first. Unloading continues by 4

removing the remaining outermost fuel cell by cell. The center cell would be the last removed.W A spiralloading program is one by which fuel is loaded on the periphery of l the previously loaded fueled region beginning around a single SRM. Spiral unloading l and reloading will preclude the creation of flux traps (moderator filled cavities surrounded on all sides by fuel).

1 During spiral unloading, the SRMs shall have an initial count rate of > 3 cps with all l rods fully inserted. The count rate will diminish during fuel remova!. Under the special  ;

i condition of complete spiral core unloading, it is expected that the count rate of the SRMs will drop below 3 cps before all of the fuelis unloaded.

Since there will be no reactivity additions, a lower number of counts will not present a hazard. When all of the fuel has been removed to the spent fuel storage pool, the SRMs will no longer be required. Requiring the SRMs to be operational prior to fuel removal assures that the SRMs are operable and can be relied on even when the count rate may go below 3 cps.

During spiral reload, SRM operability will be verified by using a portable external source every 12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br /> until the required amount of fuelis loaded to maintain 3 cps. As an alternative to the above, up to two fuel assemblies will be loaded in different cells containing control blades around each SRM to obtain the required 3 cps. Until these assemblies have been loaded, the 3 cps requirement is not necessary.

4 (1) Prior to initiating spiral unloading, up to five cells may be unloaded, provided the remaining fueled portion of the core is contiguous and connected to all four SRMs.

Fuel bundles are considered contiguous when loaded face adjacent.

Revision 192 Amendment No. A1, 46, 49,137,140 B 3/4.10-2 9703200138 970307 PDR ADOCK 05000293 P PDR t