ML19352A832

Provides Addl Info Requested in NRC 801112 Ltr Re Low Flow Feedwater Control & Reactor Water Cleanup Sys Reroute.Low Flow Control Sys Meets Intent of Section 3.4.4.3 of NEDE- 21821-A.Rerouting Warm Cleanup Water Sys Unwarranted

ML19352A832
Person / Time
Site:	Oyster Creek
Issue date:	05/22/1981
From:	Finfrock I GENERAL PUBLIC UTILITIES CORP.
To:	Eisenhut D Office of Nuclear Reactor Regulation
References
RTR-NUREG-0619, RTR-NUREG-619 NUDOCS 8106020193
Download: ML19352A832 (2)

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Parsicoany New Jersey 07C54 201 263-6500 TELEX 136-432 Wnter s Direc: Cia Numoer May 22, 1981

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51r. Darrell G. Eisenhut, Director I Division of Licensing

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Dear Mr. Eisenhut:

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Subject:

Oyster Creek Nuclear Generating Station '< ', ' ' V Docket No. 50-219 NUPEG-0619 By letter dated April 9,1981, w provided you with a partial response to your letter of Noverter 12, 1980. This letter provides the additional info mation requested.

1. Ecw Flow Feedwater Ccntrol The NFC reccrmerds having a low-flow controller with the characteristics described in Section 3.4.4.3 of NEDE-21821-A. At Cyster Creek there is installed two electropneumatic main feedeater control valve bypass valves. A single centroller, which can only be selected to one valve at a time, on panel 5F/6F in the control rocm supplies a signal to two 1/P converters for operation of these valves. Their purpose is to provide low flow feedwater control during startup, standby, and shutdown periods when fee &ater demand is lcw.

The Oyster Creek Feedwater icw flow controller does not have the capability for autcmatic control and therefore can only be operated in the manual mode.

This precludes themal cycling due to hunting in the autccutic centrol logic.

Oteraticn in the manual mcde requires the operatcr to establish a feedficw and then it is only adjusted as steam ficw demand changes.

We have reviewd our installed system and feedwater system operating procedures against the concepts cutlined in NEDE-21821-A and have determined that the low flow control system at Oyster Creek dces meet the intent of Sc< tion 3.4.4.3 by minimizing feedwater en-off events at icw powr levels. g

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2. Reactor Water Cleanup System Fercute The NBC has rectemended the rerouting of the reactor water cleanup systen to all feedwater nozzles. We do not consider that rercuting of the cleanup water return line to the feedwater cystem is necessary. The reasons for this are as follows:

1. 'Ihe design of the Oyster Creek spargers incorporates flow baffles which limit rapid tenperature cycling in the feedwater nozzle such that resulting alternating stresses are less than the endurance limit even for continuous flow of 100* F feedwater. (Test data supporting this is presented in GE report NEDE-21821, see Figure 4-33). As a result, the slight increase in feedwater temperature which is cbtained by rerouting the reactor cleanup water return to the feedwater system is not required.

2. In the case of Oyster Creek, rerouting of cleanup water to the feedwater systen would have to be dere inside contamnent in order to preserve the cleanup function during refueling when the feedwater system is isolated.

(This function has been found to be necessary to achieve adequate water clarity). Rerouting of the cleanup water inside contairrent is a significant piping change and requires adding two mixing tees in the feedwater lines near the reactor vessel. These mixing tees wculd be subjected to relatively severe thermal duty in locations which are non-isolable frcm the reactor and which are not readily accassible for in-service inspections.

Based on the above, we consider that for Oyster Creek the marginal imprevement achieved by rerouting the warm cleanup water return line to the feedwater system is not a sufficient improvement to warrant this change.

Should you have any questions concerning this letter, please contact Mr. Jim Knubel, BWR Licensing Manager at 201-299-2264.

Very truly yours,

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IvanR.Finfrddk, .

Vice President - JCP&L Director, Oyster Creek ij J

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