PNO-III-89-049, on 890731,reactor Operators Manually Scrammed Reactor from 25% Power as Water Level in Reactor Approached High Level Reactor Trip Point.Caused by Rupture in Bellows on Feedwater Header.Outage Expected to Last Approx 4 Days

PNO-III-89-049 on 890731,reactor Operators Manually Scrammed Reactor from 25% Power as Water Level in Reactor Approached High Level Reactor Trip Point.Caused by Rupture in Bellows on Feedwater Header.Outage Expected to Last Approx 4 Days

ML20247R225
Person / Time
Site:	Clinton
Issue date:	08/01/1989
From:	Knop R, Ring M NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION III)
To:
References
PNO-III-89-049, PNO-III-89-49, NUDOCS 8908070396
Download: ML20247R225 (1)

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PRELIMINARY NOTIFICATION OF EVENT OR UNUSUAL OCCURRENCE PHO-III-89-49 Date August 1, 1969 9t9 This preliminary notification constitutes EARLY notice of events of POSSIBLE safety or public interest significance. The infctmation is as initially received without verification or evaluation, and is basically all that is

-known by the Region III staff on this date.

Facility: Illinois Power Company Licensee Emergency Clinton Classification:

Clinton, IL 61727 Unusual Event Alert Docket No. 50-461 Site Area Emergency General Emergency X Not Applicable

Subject:

FEEDWATER HEATER RELIEF VALVE REPAIR OUTAGE On July 31, 1989, the reactor operators manually scrammed the reactor from about 25 percent power as water level in the reactor approached the high level reactor trip point.

Prior to the shutdown, the plant had been operating at 100 were experienced with the moisture separator reheater (MSR) percent power and feedwater when difficulties heater systems.

Operators began reducing power to remove the MSR from service when they observed an increase in the level in the reheater drain tank, an increase in the flow in the off-gas system, and a decreasing vacuum in the main condenser. Operators continued to rapidly decrease power because of the decreasing condenser vacuum. At about 25 percent power with the turbire being taken offline, bypass valves being placed in operation and a main feedwater pump being taken off line, difficulties were experienced in controlling reacter water level with the feedwater control system. When operators were unable to control the increasing reactor water level, the operators manually scrammed the reactor before the level reached the automatic scrcm point.

Inspection of the feedwater heaters and drain system disclosed that the bellows on two relief valves one feed water hea?er had ruptured. This created an air in leakage path and contributed to the decreasing condenser vacuum. The licensee expects the outage to last about four days for repair of the valves, inspection of other relief valves, and other maintenance. The resident inspectors will monitor the licensee's activities.

The State of Illinois will be notified.

The Headquarters Operation Center was notified of the scram at 11:40 p.m. (CDT) on July 31, 1989. This information is current as of 1 p.m., August 1, 1989.

CONTACT:

4fff M. Ring 7

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R. Knop FTS 388-5602 FTS 388-5547 DISTRIBUTION:

WHITE FLINT NORTH 1 MNBB REGIONS FAX TO:

Chairman Carr CA XEUU RI IHP0 4 .l; 6 Comm. Roberts OGC ARM RII NSAC w.a 1 4

Comm. Rogers OI OIA RIV Licensee G :A g 3 i Comm. Curtiss SECY EDO NRR NL RY Mali. TO:

NRC Ops Ctr .

PDR (8/634-u q:30 6

gg GPA/SLITP/PA NMSS RES DCS (Orig.)

ALSAP ACRS DOT (Trans. Only)

OE Rev. 07/05/89 8908070396 890801 PDR I&E

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