ML20054G629

Forwards Facility Operating Experience Rept for Jan 1981- Jan 1982,including Info Provided by Region 2

ML20054G629
Person / Time
Site:	McGuire
Issue date:	06/18/1982
From:	Birkel R Office of Nuclear Reactor Regulation
To:	Adensam E Office of Nuclear Reactor Regulation
References
NUDOCS 8206220149
Download: ML20054G629 (5)

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JUN 181982 Docket Nos: 50-369/370

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Elinor G. Adensan, Chief ##

MEMORAliDUH FOR:

Licensing Branch No. 4 N Division of Licensing G difyI EC~ D.D3 -

n B FRO?t: Ralph Dirkel, Project Manager g 7882A g-Licensing Branch No. 4  %

Division of Licensing '#$;

SUBJ ECT: MCGUIRE UllIT 1 OPERATING EXPERIENCE !M5('(&

Enclosed is the operating experience report for ItcGuire Unit I which covers the period of January 1,1981 to January 31, 1982. This report includes the information provided by Region II. AE00 could not assist usont51sreport.

f Ralph Birkel, Project Manager Licensing Branch Ho. 4 Division of Licensing

Enclosure:

As stated DISTRIBUTION Docket File (50-369/370)

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. I' MCGUIRE UNIT 1 OPERATING EXPERIENCE INTRODUCTION The McGuire Nuclear Station, Unit 1, is a PWR Westinghouse 4-loop reactor coolant system with a containment that employs a ice condenser pressure-suppression system.

The staff's review of the operating license application was issued in the SER, dated March 1978; however, following the TMI-2 accident the Commission " paused" in its licensing activities to assess the impact of TMI-2 accident.

The McGuire review resumed based on Commission guidance, the requirements derived from the NRC's Action Plant (NUREG-0660) and found in NUREG-0694, TMI-related Requirements for New Operating Licenses. ,

Supplement No. 4, dated January 1981 was issued in support of a Fuel Load and Zero Power License and Supplement No. 5, dated April,1981 was issued in support of a full power license for Unit 1. Unique;to this application was the need to install a hydrogen mitigation system since ice, condenser plants have relatively small containment volumes and a containment design pressure of 15 psig. A TMI-2 type of accident releases large volumes of hydrogen to containment; consequently some means is required to assu/e containment integrity. An interim distributive ignition system is used at McGuire. A permanent hydrogen mitigation system is still under review and McGuire Unit 1 was licensed on the basis that our near tem TMI requirements were satisfied and the longer tem TMI issues would be fulfilled as stipulated under the conditions of the license.

STARTUP AND OPERATING HISTORY Fuel Load and Zero Power License The license was issued on January 23, 1981 and fuel loading was completed on February 4,1981. For the next two months the licensee was engaged in filling and venting of the reactor coolant system and with cold precritical testing. Hot precritical testing was initiated in mid-April and not completed until mid-July due primarily to vario'us caponent leaks in the reactor coolant system. Numerous reactor coolant system check valves failed leakage test criteria. Leaks also developed on the residual heat removal pump flanges requiring disassembly and replac emnt. The abnomal number of leakage problems was attributed to the long lay-up following the TMI-2 accident.

Low Power License (5%)

Although the licensee was issued a 5% operating license on June 12, 1981, precritical testing was not completed until late July due, as mentioned previously, to a series of system problems which required draining, refilling and venting several tims to accommodate repairs. Approximately three months were devoted to these efforts. Initial criticality was reached on August 8,1981. By the end of August low power testing was successfully completed. All testing was completed to our satisf action wi thin the restricted power operation not to exceed 5% of rated core themal power.

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o Full Power License (100%)

The full power license was issued on July 8,1981, which pennitted the licensee to proceed with the normal power ascension program that is described in the licensee's Final Safety Analysis Report. This is a test program of power level escalation in successive stages to closely examine, at each stage of power operation, both the reactor and unit operational characteristics.

There were several incidents which have delayed the McGuire power ascension program. Briefly these are:

a) September 14, 1981: Three day delay due to inability to completely transfer automatic control function of the auxiliary feedwater system to the local station during a loss of control room test. Correction involved circuit modi fications.

b) September 28, 1981: Seven days delay when a drain line on a turbine governor valve failed.

c) October 10, 1981: Ten days delay in repairing a body-to-bonnet leak on valve I

NDl, the first residual heat removal system isolation valve in series off the reactor coolant system.

d) November 15, 1981: Nine days delay perfonning eddy current testing of the tubes in steam generator "A". Inspection was performed as a precautionary measure because of recent findings of significant tube wastage in foreign reactors having steam generators similar to those at McGuire.

e) Decenber 2,1981

Thirty-one days lost due to an unplanned outage for repair of a damaged hydrogen cooler in the main generator. The hydrogen cooler was damaged by water hammer during restoration of secondary systems following an unsuccessful loss-of-offsite power test.

Incidents described i.n' a), b) and c) are not unusual for a new plant starting up. -

However, the additional eddy current testing (d)) and the damage to the hydrogen cooler (e)) are unusual incidents.

The additional eddy current testing resulted following recent tube failures of Westinghouse preheat type steam generators discussed below:

Ringhals Unit 3, a three-loop Westinghouse plant in Sweden, was shut down on October 21, 1981 because of a 2.6 gpm primary-to-secondary l eak . Before the leak, the unit had been operating at power levels l greater than 50% for approximately five months. The steam generators,

! W preheat type, are similar in design (Model D) to those at McGuire Unit 1, the only domestic operating plant with this type of steam l ge nerator.

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The leaking tube was located within the preheater section on the cold leg side of the stean generator. The ECT results revealed -numerous tubes with ECT indications localized within the preheater section at baffle plate loca-tions. The tubes affected are in the peripheral rows (close to the steam generator shell) adjacent to the feedwater inlet. There are approximately 100 tubes with ECT indications for each steam generator. Approximately 45 of the tubes with ECT indications have wall reductions of greater than 50%.

The most recent eddy current testing of the steam generator tubes at Almaraz Unit 1 in Spain also revealed significant tube wall reduction at locations similar to those at Ringhals Unit 3. Almaraz Unit 1, with steam generators similar to those at Ringhals Unit 3 and McGuire Unit 1, had been operating at various power levels, including full power, for about four conths. ,

Westinghouse believes these ECT indications are attributable to excitation of the steam gendrator tubes from high fluid velocities and that the tube walls are being worn down from vibrational rubbing against baffle plates in the preheater sections of these steam generators.

Westinghouse further believes that a reduction of a flow velocity by controlling total feedwater flow should reduce the potential for vibration.

The licensee completed eddy current testing of approximately 170 tubes in steam generator A at McGuire Unit 1 on November 19, 1981 to determine if similar problems are being experienced in the McGuire steam generators. Pre-liminary findings show tube wall degradation no greater than 10%.

Due to potential wastage concerns with the McGuire steam generator tubes, the staff has limited power operation of the unit to no greater than 75% for limited time periods. Between January 3 and January 31, 1982, the unit operated at 50% power for most of the time in order to reduce any potential for flow induced vibration on the steam generator tubes by reducing feedwater inlet flow velocities. 'This was done as a precautionary measure to preclude problems experienced with foreign reactors. Power was escalated to 75% and 90% for a few

. days, and to 100% for one day.

Inspection and Enforcement History During the period of January 26 to August 8,1981, Region Il conducted 18 inspections at the site, including seven report periods for the resident inspector. Twenty-one violations were cited against the licensee, all of the Severity Levels V or VI categories. None of the violations were considered significant enough to warrant an enforcement meeting with the licensee or civil penal ty. Thirteen of the violations involved operational activities, including

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five related to health physics concerns, and eight were related to construction activities. Also, during this period 125 Licensee Event Reports were issued by Duke concerning McGuire 1. The reported events represented no threat to the public safety since the reactor had not yet been made critical.

From August 8 (initial criticality) to the end of 1981, 18 inspections were conducted by Region II. Six violations were identified, all in Severity Levels V or VI category. One violation involved security, two housekeeping,.and three opera tion s. The operational violations involved failure to make an adequate log book entry; and improper tripping of a particular safety circuit, and misinter-pretation of a test prerequisite. There were 15 unplanned reactor trips and three safety injections while the reactor was at some power level. One of the safety injections did not introduce water into the reactor coolant system. There were 134 Licensee Event Reports (LERs) issued during this period. Of the total of 259 issued in 1981, 194 were found, after evaluation, to have been reportable.

Many of the difficulties included above are not unusual and can be expected in starting up a new plant. The items of most concern were poor communication between operations and the support staff, failure to follow procedure, and in some instances, inadequate prodedures.

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