ML20217B677

Exam Rept 50-327/OL-91-01 on 910220.Exam Results:Retake Requalifications Simulator Exams Were Administered to One RO & Three Sros.All Operators Passed Exam.No Crew Simulator Evaluations Performed

ML20217B677
Person / Time
Site:	Sequoyah
Issue date:	03/05/1991
From:	Lawyer L, Moorman J NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION II)
To:
Shared Package
ML20217B653	List: ML20217B648 ML20217B677
References
50-327-OL-91-01, 50-327-OL-91-1, NUDOCS 9103120181
Download: ML20217B677 (4)

Text

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U%1TED STATES

/g Mooq4. NUCLEAR REGULATORY COMMISSION

~' REGION 11

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101 MARIETTA STREET, N.W.

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MC10SURE 1 EXAMINATION REPORT N0. 50-327/0L-91-01 Facility Licensee: Tennessee Valley Authority P. O. Box 2000 Soddy-Daisy, TN 37379 Facility Name: Sequoyah Nuclear Plant Facility Docket Nos.: 50-327 and 50-328 Retake requalification operating tests were administered at the Sequoyah Nuclear Plant near Soddy-Daisy, Tennessee.

Chief Examiner: L ~-

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James H. Moorman,'III V Da~te Approved By: MD 4 7/

Lawrence L. Lawyer, Chief (/ Date Operator Licensing Section 1 Division of Reactor Safety

SUMMARY

Simulator examinations were administered on February 20, 1991.

Retake requalification simulator examinations were administered to one Reactor Operator and three Senior Reactor Operators. All operators passed their examination. There were no crew simulator evaluations performed.

9103120181 910306 PDR ADOCK 0D000327 l V PDit a _ - _ -__- -___- _ _ _ ____ _ _ _ _ _ _ - _ _ _ - - _ _ _ - _ _ - - _ _ _ _ - - _ _ _ __ _ -

1 REPORT DETAILS

1. Facility fmployees Attending Exit Meeting M. Lorek, Operations Superintendert C. Benton, Operations Training Manager R. King, Operations Training Instructor G. Sanders, Operations Training In;tructor

2. Examiners

• J. Moornan, NRC, Region 11 R. McWhorter, NRC, Region 11 C. Casto, Chief, Operator Licensing Section 2, Region 11

• Chief Examiner

3. Exit Meeting At the conclusion of the site visit, the examiners met with representatives of the plant staff to discuss the results of the examination.

The operators showed improvement in the areas of emergency plan usage and emergency procedure implementation which were identified as generic weaknesses during the previous requalification exams.

Although there wre no exas failures, operator performance was noted as weak in some areas. In two of the three scenarios, the Assistant Shift Operations Supervisor (AS05) caused significant delays in accident mitigation by setting artificial limits on plant parameters during cooldown a"d/or depressurization phases of accident mitigation. During the scenario which involved a faulted and ruptured steam generator, the AS0S chose to maintain primary systeni (RCS) pressure at 1200 psig in an effort to maintain a largo subcooling margin when the procedure directs a rapid cooldown and depressurization of the RCS. The procedure does not specify the pressure to be maintained. The intent of a rapid cooldown and depressurization is to lower the differential pressure between the ruptured steam generatcr and the RCS. By keeping RCS pressure at 1200 psig, the operator delayed the process of lowering the differential pressure and allowed the RCS leak, and hence offsite release, to continue longer than was necessary.

In the scenario involving a loss of heat sink, the ASOS chose to keep steam generator pressure at 600 psig while reestablishing feedwater to the generator with the condensate system. The loss of heat sink procedure does not specify a pressure to use. Since 600 psig is only slightly lower than the condensate booster pumps' shutoff head, thir

aused a lower flow into the steam generators than would have occurred if there was a lower steam generator pressure. This caused an unnecessary delay in exiting the heat sink recovery procedure.

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., aport Details 2 The Shift Technical Advisor kept abreast of plant conditions by independently following a copy of the emergency procedures. The operators rarely used the STA to assist with technical or other problems during the scenarios.

Telephone communications in the simulator do not allow board operators to communicate directly to in-plant operators as they do in the plant.

This requires all communications to go through the ASOS, and on occasion the Shift Operations Supervisor, and becomes a burden during emergency plant operations. This could also result in negative training since the plant communications are arranged differently. '

Although E0P usage was seen to have improved, there was another aspect which could be improved. Reports from the board operators to the procedure reader often did not directly answer the step that the procedure reader was reading. For example, if the step read, "Is pressurizer pressure greater that 1750 psig?", the board operator would reply "It is 1810 psig" instead of merely replying in the affirmative.

'This caused one ASOS te request clarification which delayed procedure implementation.

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ENCLOSVRE'2 SIMVLATION FACIllTY FIDEllTY REPORT Facility Licensee: Tennessee Valley Authority Facility Docket Nos.: 50-327 and 50-328 Operating Tests Adn.inistered On: February 20, 1991 This form is used only to report observations. These observations do not constitute audit or inspection findings and are not, without further

-verification and review, indicative of noncompliance with 10 CFR 55,45(b).

These observations do not affect NRC certification or approval of the simulation facility other than to provide information which may be used in future evaluations. No licensee action is required in response to these '

observations.

During the conduct of the simulator portion of the opera; ng test, the following items were observed:

This exam used the simulator model which will be completely replaced prior to certification. There were no new problems identified.

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