ML20140F733

Documents 860305 Meeting Between Util & Region.Info Provided by Util Re Feedwater Sys & Recent Plant Operating History Shows Majority of Problems Solved.Reportable Events Re Operational History Discussed.List of Attendees Encl

ML20140F733
Person / Time
Site:	River Bend
Issue date:	03/18/1986
From:	Gagliardo J NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION IV)
To:	William Cahill GULF STATES UTILITIES CO.
References
NUDOCS 8604010143
Download: ML20140F733 (4)

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-In Reply Refer To:

Docket: 458 Gulf' States Utilities ATTN: William J. Cahill, Jr.

Senior Vice President River Bend Nuclear Group '

P. O. Box 2951 Beaumont, Texas 77704 >

Gentlemen:

This letter documents the meeting held in the Region IV offices on March 5, 1986, between members of the staffs of Gulf States Utilities (GSU) and Region IV. Members of the staff of the Office of Nuclear Reactor Regulation also participated in this meeting by means of a telephone conference connection.

A list of the attendees is attached.

The following paragraphs delineate our understanding of the information provided by the GSU staff concerning the feedwater system and recent plant 1 operating history at River Bend. If you believe that we did not understand the presentations made by your staff, please provide us with additional information within 20 days of the date of this letter.

Feedwater System. River Bend has experienced difficulty with several parts of the feedwater system. The following sunnarizes problems found and corrective actions taken.

o Short Cycle Recirculation. Piping modifications have been made. This appears to have corrected the vibration problems previously experienced at low power, but this is based on limited observations. An additional modification which might be made (if required) would be to relocate some

-valves, but this decision will be made after more data on the currer.t magnitude of the vibration problem is gathered and evaluated.

o Minimum Flow Recirculation Lines. There was an erosion problem in the minimum flow recirculation lines. This erosion primarily occurred in the 4" diameter safe end downstream of the back pressure control valves. G5U has replaced the'4" carbon steel piping downstream of the control valves with 10" stainless steel pipe. This has reduced the erosion damage noted.

A further modification is under review,' but this would not be installed durin the near term.

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Gulf States Utilities o Long Cycle Recirculation Flow. This was used more than had been originally anticipated because of the problems with the other recirculation line and the rainimum flow line. Engineering is evaluating this' operating experience to determine if additional modifications are necessary.

o Feed Pump Lube Oil _ Bypass of Cooler. GSU has installed thermostatically controlled lube oil cooler bypass valves for two of the three feed-pumps. The modification will'be installed on the third feed pump when an outage occurs. This modification prevents overcooling lube oil when heat

. loads on the service water system are low. The bypass valves nominally fail shut, thus directing all lube oil through the cooler.

o Sticking Feedwater Regulation Valves. GSU has modified two'of three

'feedwater regulation valves. The modification consisted of machining the stainless steel plug and the cage assembly and of surface hardening these components. The licensee will modify the third feedwater regulation valve in the near future. The licensee believes that this type of feedwater valve with the soft internals is unique to the River Bend feedwater system.

s o Vibration of the "A" Feedwater Pump. This pump had vibrated during operation, causing a gland seal cooling line to break. Th's cooling line has been modified and repaired. The pump manufacturer has _ informed GSU g.

that the vibration is currently within acceptable limits, but the

' licensee desires to minimize pump vibration. (Each feed pump can supply about 40% of total feed requirements; there are three electric feed pumps).

Feedwater Regulation Valve Position Indication. The control room panel indication of feedwater regulation valve position is a demand signal indication, not actual valve position. The licensee l.is working on a design change which will provide actual valve positibn. For the interim, operators are using a computer indication of actual valve position to compare to the demand signal. The licensee had identified 1 other i

valvesthathavedemandsignalpositionindicationbutdoes"}tonsider these to be as crucial as the feedwater regulation valves. 6 o Feedwater Heater Level Controls. The licensee modified the instrument piping to preclude false signal indications and has provided annunciation of drain valve closure.

In sunnation, GSU believes that the majority of the feedwater problems have been solved and that the remaining problems are well in hand.

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Gulf States Utilities h Operational History. River-Bend site had experienced more reportable events <

- in the period 1 month'before full power licensing to 2 months after full power licensing than did comparable plants. For example, the number _ of events after full power licensing.was 18 per month. The licensee reported that for the month of February 1986, therc had been 4 events reportable undar 10 CFR 50.73.

' These events were discussed.

'rir;n131 au f.14 J. E. Gagliardo, Chief

- Reactor Projects Branch

Attachment:

As stated cc:

S. Stern, NRR J. Jaudon, RIV R. Ireland, RIV W. Butler, NRR S. Newberry, NRR E. Weiss, IE

- bec:

RPB Reading File SRI-RB RIV Docket File T

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. .o ATTENDANCE LIST t

Attendance at the GSU - NRC meeting on March 5, 1986, at the NRC Region IV Office:

Gulf States Utilities

. J. Booker, Manager E. Goldman, Feedwater System Task Force Leade'r T. Plunkett, Plant Manager i W. Reed, Director, Nuclear Licensing M. Reeves Engineer J. Wright, Supervisor, Mechanical Engineering Cajun Electric Cooperative J. Gore NRC l J. Gagliardo, RIV R. Ireland, RIV  !

J. Jaudon, RIV l R. Becker, NRR I W. Butler, NRR l S. Newberry, NRR S. Stern, NRR l 6 - .- .

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