NUREG-0611, Forwards Safety Evaluation Finding Auxiliary Feedwater Sys Adequately Designed,Maintained & Operated.Finding Predicated on Implementation of Listed Recommendations Agreed to During 860929-1002 Visit

Forwards Safety Evaluation Finding Auxiliary Feedwater Sys Adequately Designed,Maintained & Operated.Finding Predicated on Implementation of Listed Recommendations Agreed to During 860929-1002 Visit

ML20214S344
Person / Time
Site:	Prairie Island
Issue date:	11/26/1986
From:	Lear G Office of Nuclear Reactor Regulation
To:	Musolf D NORTHERN STATES POWER CO.
Shared Package
ML20214S348	List: ML20214S413 NUREG-0611, Forwards Safety Evaluation Finding Auxiliary Feedwater Sys Adequately Designed,Maintained & Operated.Finding Predicated on Implementation of Listed Recommendations Agreed to During 860929-1002 Visit
References
REF-GTECI-124, REF-GTECI-NI, RTR-NUREG-0611, RTR-NUREG-611, TASK-124, TASK-OR TAC-61519, TAC-61520, NUDOCS 8612080258
Download: ML20214S344 (4)

Text

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Mr. Dave M. Musolf, Manager Nuclear Support Services Northern States Power 414 Nicollet Mall Midland Square, 4th Floor Minneapolis, MN 55401

Dear Mr. Musolf:

Ref: Reliability of Auxiliary Feedwater (AFW) Systems The comission has completed its assessment of the overall reliability of auxiliary feedwater (AFW) systems of the Prairie Island Nuclear Generating Plant Unit Nos. I and 2. The review is related to our Generic Issue No.124,

" Auxiliary Feedwater System Reliability" which indicates that the AFW systems at Prairie Island fall in the low reliability range based on an analysis presented in NUREG-0611 (January 1980).

The approach adopted by the staff to resolve this issue included an audit of plant variables that directly or indirectly affect the availability and reliability of the AFW system. The audit were (1) design configuration, (2)maintenance, plant variables (3) considered surveillance in the and testing procedures and practices, (4) operating procedures, (5) personnel training, (6) system layout, (7) instrumentation and controls, and (8) accessibility for operator recovery actions following potential malfunctions. Our review also included the reliability analysis (RA) submitted by your letter dated April 24, 1986, the system modifications that resulted from that RA, and all of the post-TMI modifications.

Based on our review we find that the auxiliary feedwater systems of the Prairie Island Nuclear Generating Plant Unit Nos. 1 and 2 are adequately designed, maintained and operated. In addition, the system design, maintenance and operating practices adequately address the concerns of our Generic Issue 124.

On this basis we conclude that the AFW systems at Prairie Island are sufficiently reliable to perform their intended design function under normal operating conditions and during transient and accident conditions. This conclusion is predicated on implementation of the following recommendations discussed in the enclosed safety evaluation which we understand you agreed to during our recent site visit (September 29, through October 2,1986).

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8612080258 861126 PDR ADOCK 05000282 p PDR v j

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1. The main' isolation valves of the three condensate storage tanks are

'"normally blocked open by thin wire clips. . These thin wire clips on each valve should be replaced with positive locking devices.

2. The cooling water supply valves for the four AFW pumps are not easily accessible for potential manual recovery action. Physical means in assisting the operator to manually operate these valves should be provided and adequate training should be performed.

3. The emergency lighting in the turbine driven AFW pump cubicles is not adequate, and should be improved.

4. Engineering and operating personnel should receive more maintenance training to enhance their trouble-shooting capability.

5. Emergency procedures dealing with the loss of heat sink instruct the operator to isolate the broken steam generator and guide the. operator to perform several safety functions that finally resort to the " Feed and Bleed" cooling mode without reference to the possible use of the broken steam generator. The use of the broken steam generator before resorting to the " Feed and Bleed" cooling mode should be evaluated and be included in the emergency procedures, if appropriate.

44 6 The updating of maintenance and surveillance procedures between the two units should be closely coordinated between the systems engineers and revisions to these procedures should be done in a timely manner.

7. The emergency operating procedures require that the motor driven auxiliary feedwater pump be started with the discharge valves in an open position when the pumps are in a cross connected mode. There appears to be discrepancy in the procedures in that the pumps should be started against a closed valve. This discrepancy should be resolved in the next procedure update.

8. The eight motor-operated throttle valves downstream of the AFW pumps are not easily accessible for manual operator recovery action. Since these valves would be used to control the AFW flow during the course of' postulated transients, access to these valves should be improved and physical means to assist the operator to manipulate them should be provided. Adequate training should also be performed.

The implementation of the system modifications that resulted from the AFW reliability analysis and the resolution of these recommendations are to be addressed in the next revision to the updated safety analysis report in order to complete the resolution of GI 124 for your plant.

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This completes our work efforts.on the reliability of the auxiliary feedwater systems at the Prairie Island Nuclear Generating Plant and TAC Nos. 61519 and 61520 are closed.

A copy of our Safety Evaluation is enclosed.

Sincerely, Original signed Agt Jiorge E. Leat George Lear, Director

PWR Project Directorate #1 Division of PWR Licensing-A

Enclosure:

Safety Evaluation Report Distribution Central File RSIB R/F DSR0 C/F

TNovak i HThompson HDenton RVollmer SDiab PNorian WMinners

! DCDilanni BSheron Glear PWR PD#1 R/F SDiab c/f

• See previous concurrenc RSIB:DSR0* RSIB:DSR0* RSIB:DSR0* PD#1:DPWR-A* D D: :PD#1:DPWR-A SDiab:sm PNorfan WMinners DCDilanni BS n tsp is Glear 11/19/86 11/19/86 11/17/86 11/20/86 11/g/86 11/4686 11/,2f/86 l

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Distribution Copies: .

' Docket Files:

NRC PDR Local PDR PAD #1 r/f PAD #1 p/f TNovak, Actg. DD NThompson, DHFT OGC-Bethesda EJordan BGrimes JPartlow Glear PShuttleworth DDilanni SDiab PNorian WMinners BSheron TSpeis RHerman ACRS (10)

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