ML20112C647

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Unit 2 Gap Insp Plan for Fourth Refueling Outage
ML20112C647
Person / Time
Site: Arkansas Nuclear Entergy icon.png
Issue date: 01/03/1984
From:
ARKANSAS POWER & LIGHT CO.
To:
Shared Package
ML20112C642 List:
References
PROC-840103, NUDOCS 8501110312
Download: ML20112C647 (5)
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ATTACHMENT 4

1 ANO-2 SHOULDER GAP INSPECTION PLAN FOR THE FOURTH REFUELING OUTAGE

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J~ fANO-2 Shoulder Gap Inspection Plan For The Fourth Refueling Outage

. ' 1.-- Introduction Shoulder gap is the distance from the top of a fuel rod to the bottom of the l upper flow plate. . Measurements _of this gap have been made on select ANO-2 fuel assemblies after each cycle of operation to date. At the end of cycle 2, after being exposed to two full cycles of operation, the ga'p closure

rate measured.on some Batch C assemblies indicated that rod to plate contact imight1 occur during their third-cycle of exposure. Accordingly, a modification

.using shims was devised to increase the available gap. In all, 30. Batch C

. ;- . assemblies were shimmed'before cycle ~3 exposure. References'l and 2 present

further information on the measured gaps and the modification procedure.

To assure adequate gap would be available for Batch D assemblies, which were ,

scheduled for their third exposure during cycle 4 an inspection plan for

- theexaminationoftheseassembliesduringthethIrdrefuelingoutagewas

prepared and submitted to the NRC (Reference 3). The results of the in.spection indicated that none of the assemblies in the cycle 4 core would experience gap closure. However, since a fourth cycle of exposure was tplanned for a batch D test assembly (AKD040), as part of a DOE high burnup test, this assembly was shimmed during the 2R3 refueling. References 4, 5,
and 6 present further details on the measurements and our analyses. The NRC concurred that_ shoulder gap spacing would remain adequate for cycle 4 operation; however, they requested that refueling outage surveillance continue until.such time as an approved analytical model for shoulder gap prediction was available (Reference 7).

,- 2 .' Cycle 5 Core Composition

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The' cycle 5 core will be composed of 8 Batch A, 1. Batch D, 52 Batch E, 56

, Batch F and 60 Batch G assemblies. Prior to cycle 5 operation the Batch ti

" "assemb1Ieswillhavetwocyclesofoperation,-theBatchAandFassemblies

j. and the Batch G assemblies will'be
D Jwill

~ new. have a differences Some single cycle of operation,ign in assembly des exist between the batches.Table I

1C lists the major improvements that have been incorporated into the assemblies l'

design to assure adequate shoulder gap.-

g 3. ' Shoulder Gap Inspection Plan For The Fourth Refueling Outage

The peripheral rods'on all four faces of five Batch D assemblies and ten Batch'E assemblies will'be measured for shoulder. gap. The assemblies in

' Batch'D to be measured will be those which have previously been measured after their first and second cycles of operation. 'Of the ten Batch E~

' assemblies to be selected,'seven will have been previously measured after

. .their first exposure cycle. -The remaining three Batch E assemblies will be selected from a group of eight assemblies that will have high fluence
exposures. Batch A and F assemblies do not require measurement this outage t

since they have only been exposed to a single cycle of operation, n

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4. Analysis Procedure With their previous measurements, the Batch D data will cover three exposure cycles. The Batch E data will cover two exposure cycles and will be compared to the Batch D data to determine the extent that the Batch E shoulder gap behavior is characterized by the Batch D behavior. The data base of Batch D and E data will be used to project end-of-cycle 5 shoulder gaps for AKD040 and the Batch E assemblies. All assemblies to be used in cycle 5 will pass the following criterion:

At a 95% probability, the worst rod in the assembly will not have gap closure at the end of cycle.

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- 3 TABLE I DESIGN DIFFERENCES'BETWEEN BATCHES Increase:in Batch Shoulder Gap .From Guide Tube Designation' Orginal Ref.(in.) Fabrication >

2 :A" REFERENCE Annealed (RXA)1 DL +0.302 Annealed (RXA)

E +0.15 Cold Worked (SRA)

F +0.85 Cold Worked.(SRA)

-G +0.85 Cold Worked (SRA)

'1-Ten Batch A assemblies had cold worked, stress-relief annealed (SRA)

guide tubes. One of these 10, AKA104, is a candidate-for cycle 5.

2 The'O assembly, AKD040, was shimmed to provide an additional 0.4 inches during the cycle 3 outage. Therefore, the total' change from the reference. gap is +0.70 inches.

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REFERENCES -

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'1. ohn J R. Marshall to Robert A. Clark, Docket No. 50-368, Letter Number 2CAN128297, dated December 10, 1982.

2. John R. Marshall to Robert A. Clark, Docket No. 50-368, Letter Number

,, J, , s 2CAN938397, dated March 30, 1983.

3. -. John R. Marshall to Robert A. Clark, Docket No. 50-368 Letter Number t 2CAH98398, dated August 19, 1983.

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'4 ~ . John R.' Marshall to J. E. Gagliardo, Docket No. 50-368, Letter Number

2CAN118319, dated December 2,1983 (transniittal of report CEN-260(A)-P).

5. John R. Marshall to J.~E. Gagliardo, Docket Ni 50-368, Letter number 2CAN128386, dated December 16, 1983 (transmittal of report CEN-261(A)).
6. John R. Marshall to James R. Miller, Docket No. 50-368, Letter Number
2CAN948493, aated April 18, 1984.
7. James R. Miller to John H. Griffin, Docket No. 50-368, Letter Number

~2CMA928491, dated Februa'ry 24, 1984 (transmittal of Safety Evaluation Report).

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