ML20011E148

Responds to NRC Bulletin 89-003, Potential Loss of Required Shutdown Margin During Refueling Operations. Procedural Restriction Added to Refueling Procedure for Unit 2.Unit 1 Refueling Procedure Will Be Revised

ML20011E148
Person / Time
Site:	Arkansas Nuclear
Issue date:	01/29/1990
From:	James Fisicaro ARKANSAS POWER & LIGHT CO.
To:	NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
References
0CAN019013, CAN19013, IEB-89-003, IEB-89-3, NUDOCS 9002080185
Download: ML20011E148 (5)

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d , Arkansas Power & Ught Company "1 " 1 425 West C:Not P O Box 551 Lrme Ra:A AR 7??D3 1el s01377 4033

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L January 29, 1990 pCANP19p13 U. S. Nuclear Regulatory Commission ,

F Document Control Desk

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Mail Station P1-137 Washington, DC 20555

Subject:

Arkansas Nuclear One - Units 1 & 2 Docket Nos. 50-313 and 50-368 License Nos. DPR-51 and NPF-6 i Bulletin 89-03, Potential Loss of Required ,

Shutdown Margin During Refueling Operations .

L Gentlemen:

Pursuant to 10CFR50.54(f), Arkansas Power & Light Company (AP&L) provides ,

this response to NRC Bulletin 89-03 with respect to assurances of maintaining adequate shutdown margin during refueling operations. >

Bulletin 89-03 requested that adequate margin should be accomplished through the following actions that have been or will be taken:

1. Assure that any intermediate fuel assembly configuration (including ,

control rods) intended to be used during refueling is identified and evaluated to maintain sufficient refueling boron concentestion to result in a minimum shutdown margin of approximately 5%; and i

2. Assure that fuel loading procedures only allow those intermediate fuel assembly configurations that do not violate the allowable shutdown margin and that these procedures are strictly adhered to.

AP&L Response:

f' C-E Infobulletin 89-01 (March 14,1989), which addressed the potential

' loss of shutdown margin during refueling, was received during j preparation for the seventh refueling outage (2R7) of Arkansas Nuclear i

One - Unit 2 (ANO-2). As a result of this concern, the final core loading pattern for Cycle 8 was reviewed to determine the maximum grouping of new fuel assemblies. ANO-2 was to be refueled using the /

• total core offload / reload method. It was determined that the new core /

loading would have up to three new fuel assemblies grouped together in ,

an "L" configuration. This configuration was chosen as the limiting grouping of new fuel assemblies, in that support analysis was available which demonstrated that adequate shutdown margin was maintained for this 9002080185 900129 J tPDR--ADOCK Q 05000313 "

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configuration. To provide administrative control over placement of the new fuel assemblies, a procedural restriction was added to the refueling procedure to prohibit the placement of four or more new fuel assemblies in adjacent positions (compact 2 x 2 array).

o The restriction further recommended the use of reactor building fuel storage racks which provide acceptable separation for new fuel assemblies for intermediate storage, or other methods determined acceptable by ANO Reactor Engineering. This procedural change was implemented prior to the performance of refueling during 2R7 in October

. 1989. Except for the two fuel assemblies which contained the neutron sources, fuel assemblies were loaded in sequence into their final core locations for the next cycle and no intermediate locations were to be used. The assemblies which contained the neutron sources were twice burned assemblies and were pbced in intermediate locations which were to contain twice burned assemblies for the next cycle. in addition, a shutdown margin of at least 15% (considering control rod worth) was provided by the minimum required refueling boron concentration for ANO-2.

Prior to fuel movement for future cycles, the core loading pattern will be evaluated to verify that the restrictions implemented for 2R7 are bounding.

The ninth refueling outage (IR9) for Unit 1 (ANO-1) is scheduled to begin in October, 1990. For 1R9, a total core offload / reload is also being planned. Consequently, a review of the Unit I loading pattern has been performed, similar to that performed on Unit 2, to determine

. the maximum grouping of new fuel assemblies. Although the core loading 1 pattern for ANO-l's next cycle has not yet been established, a review of previous core loadings has shown that since Cycle 4 the new fuel has been located in a checkerboard pattern with no new fuel assemblies being placed adjacent to one another. Therefore, the ANO-1 refueling procedure will be modified to include a restriction on new fuel assembly placement, similar to that in the ANO-2 procedure, except that the restriction will prohibit the location of two or more new fuel assemblies in adjacent core locations unless specifically allowed by the new core loading pattern.

During a review of the refueling procedure used in the last ANO-1 refueling outage (Fall 1988), it was noted that some new fuel assemblies were initially loaded into intermediate positions in the core that would later be filled by once burned fuel assemblies. The new assemblies were placed in these intermediate locations to aid in the loading of burned assemblies in adjacent core locations. In the intermediate positions, the new fuel assemblies were not adjacent to other new fuel assemblies. Therefore, the effect on the shutdown

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U. S. NRC Page 3 January 29, 1990 margin by placing the new assemblies in these intermediate positions is considered to be minor. An evaluation of this practice will be i performed prior to 1R9 to assure the minimum shutdown margin is maintained. If it is determined that placement of the new fuel assemblies in these intermediate locations will reduce the shutdown if" margin below 5%, a restriction will be added to the ANO-1 refueling b procedure to prohibit this loading practice or to require an increase in the minimum boron concentration so that a 5% shutdown margin is maintained.

Revision of the ANO-1 refueling procedure to include the appropriate restrictions discussed above will be completed by October 1,1990.

3. Assure that the staff responsible for refueling operations is trained in the procedures recommended in item 2 above and understand the potential consequences of violating these procedures. This training should include the fundamental aspects of criticality control with higher enriched fuel assemblies, o

AP&L Response:

The Fuel Handling SR0s and reactor engineers who will be responsible for the next ANO-1 refueling will be briefed on NRC Bulletin No. 89-03 and the changes made to t h ANO-1 refueling procedure as a result of this concern. This brY Ng will be completed by October 1,1990, p Similarly, the Fuel H $ nag SR0s and the reactor engineers who will be responsible for the next ANO-2 refueling will be briefed on NRC Bulletin No. 89-03 and the related changes made to the ANO-2 refueling

. procedure. This briefing will be completed by February 14, 1991.

'If you have any questions concerning these responses, please do not hesitate to contact me.

Very truly yours, pr . $ c"*

ies J. Fisicaro anager, Licensing

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g s b cc: Mr. Robert Martin . . 1 U. S. Nuclear Regulatory Comission~  !

Region IV i 611 Ryan Plaza Drive, Suite 1000  !

J Arlington, TX 76011 -l l: i E NRC Senior Resident Inspector

' Arkansas Nuclear One - ANO-1 & 2  ;

t Number.1, Nuclear Plant Road  !

x Russellville, AR 72801 Mr. Thomas W. Alexion h NRR Project Manager, Region.IV/ANO-1 ~I U. S. Nuclear Regulatory Comission  !

1 NRR Mail Stop 13-0-18 r

. One White Flint North t I- i 11555 Rockville Pike -

Rockville, Maryland 20852 Mr.-Chester Poslusny

, NRR Project Manager, Region IV/ANO-2 ,

U.. S. Nuclear Regulatory Commission NRR Mail Stop 13-D-18 g- One White Flint North L' 11555 Rockville-Pike

( Rockville, Maryland 20852 r 3 .

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1 STATE OF ARKANSAS.

SS 4 < COUNTY OF PULASKI I, J. J. Fisicaro, being ' duly sworn, subscribe to and say that I am Manager Licensing for Arkansas Power & Light Company; that I have. full authority to execute this oath; that I have read the document numbered r

PCANpl9913 and know the contents thereof; and that to the best of rny knowledge, information and belief the statements in it are true, y

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N. J. Fisicaro i

SUBSCRIBED AND SWORN T0 before me, a Notary Public in and for the-

, . County and State above named, this . 29th day of Januarv ,

1990.

cc (kt W h JbOAWJ Whitaker Ka' thy D{ Notary Public

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] My Connission Expires:

7/14/04 s

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