ML18046A204

Forwards Description of Proposed Mods to Auxiliary Feedwater Sys & Implementation Schedule.Mods Will Reduce Potential for Water Hammer During Auxiliary Feedwater Operation & Assure Sufficient Flow to Steam Generators

ML18046A204
Person / Time
Site:	Palisades
Issue date:	12/01/1980
From:	Hoffman D CONSUMERS ENERGY CO. (FORMERLY CONSUMERS POWER CO.)
To:	Crutchfield D Office of Nuclear Reactor Regulation
References
NUDOCS 8012030702
Download: ML18046A204 (5)

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ibirecto~ Nuc1[4r Reactor Regulation Att Mr ~nnis M Crutchfield, Chief Operating Reactors Branch No. 5 US Nuclear Regulatory Commission Washington, DC 20555 DOCKET 50-255 - LICENSE DPR PALISADES PLANT - AUXILIARY FEEDWATER MODIFICATIONS Consumers Power Company, by letter d*ated Oct:ober 2, 1980, agreed to provide a description of proposed modifications to the auxiliary ~eedwater system and a schedule for implementing the proposed modification.

The purpose of this modification is to reduce, by means of rerouting the auxiliary feedwater lines, the potential for water hammer during auxiliary feedwater operation and to assure that sufficient auxiliary feedwater flow is provided to the steam generators to facilitate operation during normal, abnormal, and emergency conditions.

The following is presented to fulfill our commitment to provide the above information by December 1, 1980.

The existing auxiliary feedwater system (described in Palisades FSAR Chapter

9) discharges through two independently controlled branches and through check valves to the main feedwater lines immediately outside the containment.

From this point, the flow of auxiliary feedwater is through the main feedwater lines as they proceed through containment penetrations to the steam generators, and through the existing main feedwater spargers internal to the steam generators.

The modification consists of disconnecting the auxiliary feedwater lines from the main feedwater lines, routing the lines through existing spare containment penetrations to existing auxiliary feedwater nozzles (labeled Emergency Feedwater Nozzle on Figure 1) on the steam generators, and providing a separate auxiliary feedwater sparger inside each steam generator.

The piping arrangement is shown in Figure 2 and the nozzle and sparger assembly are shown in Figure 3.

The additional piping and supports will be designated seismic Category I, designed and supported in accordance with Appendix A of the Palisades FSAR.

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Director, Nuclear Reactor Regulation Palisades Plant December 1, 1980 2

The existing auxiliary feedwater nozzle.forgings will be equipped with thermal I

liners to allow cold feed injections, and the acceptable number of such cycles will be analytically determined.

The piping reaction at the nozzles will also be evaluated for acceptability.

The new spargers for auxiliary feedwater will be designed in accordance with the current design practice for CE steam generators.

A number of design features will be incorporated specifically to reduce the susceptibility to water hammer.

The piping in the vicinity of the steam generators will be sloped down away from the generators (see Figure 2).

The Sparger Will be arranged with a top discharge and provided with a water trap as shown on Figure 3 to prevent the sparger from draining when the steam generator water level drops below the sparger.

A vent will be provided at the highest point of the sparger water trap as shown.

Consumers Power Company plans to install the proposed modification at the next refueli~g outage presently scheduled for late 1981:

David P Hoffman Nuclear Licensing Ad~inistrator CC Director, Region III, USNRC NRC Resident Inspector-Palisades Attachments Figures 1, 2 and 3

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