ML20203M870

Nonproprietary Waterford Unit 3,Cycle 2 Shoulder Gap Evaluation

ML20203M870
Person / Time
Site:	Waterford
Issue date:	07/31/1986
From:	ABB COMBUSTION ENGINEERING NUCLEAR FUEL (FORMERLY
To:
Shared Package
ML19292F837	List: ML20203M870 W3P86-1685, Forwards Nonproprietary CEN-335(C)-NP & Proprietary CEN-335(C)-P, Waterford Unit 3,Cycle 2 Shoulder Gap Evaluation. Shoulder Gaps in All Fuel Acceptable Through Cycle 2.Proprietary Rept Withheld (Ref 10CFR2.790)
References
CEN-335(C)-NP, NUDOCS 8609050091
Download: ML20203M870 (6)

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WATERFORD UNIT 3, CYCLE 2 i SHOULDER GAP EVALUATION l

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COMBUSTION ENGINEERING, INC.

WINDSOR, CT.

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n, 8609050091 860902 PDR ADOCK 05000382 PDR P .

LEGAL NOTICE ~

4 THIS REPORT WAS PREPARED AS AN ACCOUNT OF WORK SPONSORED BY COMBUSTION ENGINEERING, INC. NEITHER COMBUSTION ENGINEERING "

NOR ANY PERSON ACTING ON ITS BEHALF:

A. MAKES ANY WARRANTY OR REPRESENTATION, EXPRESS OR

,- IlWLIED INCLUDING THE WARRANTIES OF FITNESS FOR A PARTICULAR PURPOSE OR MERCHANTASILITY, WITH RESPECT TO THE ACCURACY, COMPLETENESS, OR USEFULNESS OF THE INFORMATION CONTAINED IN THIS REPORT, OR THAT THE USE OF ANY INFORMATION, APPARATUS, METHOD, OR PROCESS DISCLO&ED IN THIS REFORT MAY NOT INFRINOf PMIVATELY OWNED RIGHTS;OR ,

' B. ASSUMES ANY UA81LITIES WlTH RESPECT TO THE USE OF, OR FOR i

DAMAGES RESULTING PROM THE USE OF, ANY INFORMATION, APPARATUS,

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METHOD OR PROCESS DISCLOSED IN TH6 3 REPORT.

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Waterford-3 Cycle 2 Shoulder Gap Evaluation The Cycle 2 core loading for Waterford-3 includes Batch B, C and D fuel assemblies. The initial shoulder gaps of the various fuel designs are shown in Table 1. The table shows the fuel design with the smallest initial shoulder gap is the unmodified Batch B design. An unmodified Batch B fuel

assembly will contain the fuel rod with the maximum fast fluence at the end of 21 Cycle 2. This peak axially averaged fuel rod fluence is 6.8x10 nyt(E>.821

- Mev), which includes physics uncertainty and which bounds the anticipated Cycle 2 operation. Therefore, since the unmodified Batch B fuel assemblies have the smallest initial shoulder gaps and the peak E002 fuel rod fluences, justification of the shoulder gap adequacy for the unmodified Batch B design to a rod fluence of 6.8x10 21 nyt verifies the acceptability of the shoulder gaps of all fuel designs in Cycle 2.

Reference 1 discusses a technique employing the existing measured data base for evaluating the adequacy of 16x16 shoulder gaps. This technique is based on the minimum available shoulder gap at the beginning of life, a conservatively high fuel rod growth prediction, and a conservatively low guide tube growth prediction. This methodology was employed in the justification of the ANO-2 Cycle 5 fuel (Reference 3). The three parameters identified above are discussed in more detail below:

a. The minimum available shoulder gap at the beginning of life accounts for component dimensional tolerances, elastic compression of the guide tubes, and differential thermal expansion between the fuel rods and the guide tubes. The result is to reduce the nominal initial shoulder gap (cold) by [ ] inches (hot).

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b. The limiting fuel rod growth rate observed on 16x16 fuel was in AN0-2 Batch C fuel. This limiting rate is [ ] inches of fuel rod growth per r 21 nyt. This value is assumed to be bounding for the Waterford-3 fuel 10 I

rods.

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c. Because Waterford-3 and SONGS-2 fuel assemblies have the same guide tube design (dimensions and material) and the same holddown spring forces on the guide tubes, the Waterford-3 and SONGS-2 fuel assemblies are expected to have the same guide tube growth. Therefore, the measured guide tube

? growth of the SONGS-2 fuel bundles is used to establish a conservatively low guide tube growth prediction for Waterford-3. The minimum predicted

• growth for Waterford-3 is conservatively selected as the growth associated with the lower 95/95 SONGS-2 growth rate through two cycles and the high end of the range in guide tube fluence of the SONGS-2 data.

Figure 1 shows the SONGS-2 data, the lower 95/95 of the two cycle data, the high end of the fluence range and the resulting predicted growth for Waterford-3([ ] inches). This method conservatively ignores the additional guide tube growth that the Waterford-3 fuel assembly will 21 obtain during its irradiation from 4.8x10 nyt (peak SONGS 2 value) to 21 5.6x10 nyt (minimum guide tube fluence associated with the peak fuel 21 rod fluence of 6.8x10 nyt).

Employing this technique with the bounding assumptions described above results in the shoulder gaps of the unmodified Batch B fuel assemblies being 21 acceptable at a rod fluence of 6.8x10 nyt.

To provide further assurance, the shoulder gap adequacy of the unmodified Batch B fuel assembly design was also evaluated using the SIGREEP model. This model is discussed in Reference 1 which demonstrates the acceptability of the SIGREEP model for 16x16 fuel assembly designs with Stress-Relief Annealed (SRA) guide tubes. Additional data on 16x16' fuel assemblies with SRA guide tubes has continued to show favorable comparisons to SIGREEP predictions, to the point that the justification of the SONGS-2 Batch C fuel through Cycle 3 was based on the SIGREEP model (Reference 2). The SIGREEP evaluation of the unmodified Batch B assemblies for Waterford 3 shows a fuel rod fluence capability of over 8.7x10 21 nyt (E>.821 Mev), well in excess of the peak E0C2 rod fluence.

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Since the unmodified Batch B fuel design is the limiting design in Waterford 3 Cycle 2 with regard to shoulder gap and it b" been shown to be acceptable through Cycle 2 by both the technique using the existing measured data base and the SIGREEP model, it is concluded that the shoulder gaps in all the fuel

are acceptable through Cycle 2.

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- Fuel Design h Shoulder Gap (in) r 1.332 Batch B (unmoC fied)

BatchB(modified)). 2.032

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• These fuel types had 0.7 ir.ch shims installed between the outer j guide tubes and the upper end fitting flow plate prior to operation of the fuel.

s References _

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(1) CENPD-269-P, Rev. 1-P, " Extended Burnup Operation of Combustion Engineering PWR Fuel", issued July, 1984._

(2). ;CEN-332(S)-P, " SONGS-2 End of Cycle 2 Shoulder Gap Evaluation", issued May, 1986 m (3) CCN-309(A)-P, " Arkansas Nuclear One, Unit 2 Cycle 5 Shoulder Gap 4

Evaluation", issued July, 1985'/ /

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Selection of Waterford-3 Guide Tube -

Growth Based on SONGS-2 Data i

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